Design and Implementation of an AC to High DC Voltage Generation Circuit Using Voltage Multiplier

Md. Mohasin Siddique

Department of Electrical and Electronic Engineering

Dhaka University of Engineering & Technology, Gazipur

February, 2019

Design and Implementation of an AC to High DC Voltage Generation Circuit Using Voltage Multiplier

A dissertation submitted in partial fulfillment of the requirements for the degree of

Master of Engineering in Electrical and Electronic Engineering

Md. Mohasin Siddique Student No. 112273-P

Under Supervision of Dr. Md. Raju Ahmed Professor, Dept. of EEE, DUET, Gazipur

Department of Electrical and Electronic Engineering

Dhaka University of Engineering & Technology, Gazipur

February, 2019

Declaration

I declare that this project is my own work and has not been submitted in any form for another degree or diploma at any university or other institute of tertiary education. Information derived from the published and unpublished work of others has been acknowledged in the text and a list of references is given.

Date: 25th February, 2019 Md. Mohasin Siddique

Acknowledgements

All praise is to Almighty Allah (S. T.) for having guided us at every stage of our life. I would like to convey my sincere feeling and profound gratitude to my supervisor, Dr. Md. Raju Ahmed for his guidance, encouragement, constructive suggestions, and support throughout the span of this project. Among many things I learned from Dr. Md. Raju Ahmed, that persistent effort is undoubtedly the most important one, which enables me to sort out several important issues in the area of DC voltage generation and long range wireless transmission. I also want to thank Dr. Md. Raju Ahmed for spending so many hours with me in exploring new areas of research and new ideas and improving the writing of this dissertation. I am also thankful to all my colleagues of Summit Bibiyana II, and staffs of the Department of EEE of Dhaka University of Engineering & Technology for their support and encouragement.

Most importantly, I wish to thank my parents for being my driving force and standing with me through thick and thin. Without them I would never have come so far in pursuing my dream. After all, I would like to express my gratitude to EEE Department of Dhaka University of Engineering & Technology, Gazipur for providing an excellent environment for research.

Md. Mohasin Siddique

Abstract

High voltage DC is indispensable for testing of dielectric strength of different electrical appliances and equipment’s. In this project, single phase AC to high voltage DC generation circuit is developed. Ladder network of capacitors and diodes on the basics of Cockcroft–Walton circuit is used for generation of high DC voltage.

The measurement of High Voltage DC is not easy due to risk of deadly shock. Generally, voltage divider is used to measure the high voltage. In this project wireless data monitoring system is designed for the measure of high voltage. A simple low cost Arduino, GSM and GPRS shield has been used for wireless monitoring. The Arduino is connected to the shield using GPRS wireless network internet. Real-time data is sent to a server during operation the HVDC using the GSM and GPRS shield which is stored for monitoring purposes. Therefore, the designed wireless monitoring system is save and data can be store for future use.

Temperature and short circuit current protection feature is added to the designed circuit. Therefore, if the high voltage generation circuit exceeds a temperature range or occur a short circuit then the system will disconnect the input source and save from possible damage to the system. Consequently, the designed circuit will be reliable and save.

This paper presents a voltage-doubler cascade circuit with wireless monitoring system in a compact device approach. The proposed circuit is simulation by using Proteus 8, simulation software then practically implemented in laboratory. The performance of the designed circuit is analyzed.

List of Contents

Page

Declaration IV Acknowledgments V Abstract VI List of Contents VII List of Figures XII List of Tables XV List of Abbreviations XVI

Chapter 1 Introduction

1.1 Overview 1 1.2 Importance of high voltage in power system 2 1.3 Motivation of this project 3 1.4 Objective of the project 3 1.5 Organization of the project 4

Chapter 2 Literature review

2.1 Introduction 5 2.2 Study of existing system 5 2.3 Conventional methods for high voltage DC generation 7 2.3.1 Voltage doubler 9 2.3.1.1 Half wave voltage doubler 9 2.3.1.2 Full wave voltage doubler 11 2.3.2 Voltage tippler and quadrupler 13

VII

2.4 Conventional methods for remote monitoring. 14 2.4.1 Key points of process 14 2.5 Breakdown voltage 15 2.6 Voltage divider 16

Chapter 3 System design and simulation of high voltage DC

3.1 Theory of major components used 17 3.2 Transformer 17 3.2 Capacitors 19 3.3 Diodes 20 3.4 Resistor 21 3.4.1 Potentiometer 22 3.5 Arduino-uno-R3 23 3.6 GSM/GPS/GPRS module 26 3.7 Voltage sensor 28 3.8 LM35 Temperature Sensor 29 3.9 LCD Display 29 3.10 Relay 31 3.11 Block diagram of the propose system 32 3.12 Voltage measuring system 34 3.13 Temperature measuring system 36 3.14 Over temperature protection system 37 3.15 Short circuit current (Isc) protection system 38 3.15 Final simulation 38

VIII

Chapter 4 Hardware development and performance analysis of high voltage DC

4.1 Developed hardware 50 4.2 Performance analysis 57

Chapter 5

Conclusions and Future Works

5.1 Conclusions 61 5.2 Future Works 62

REFERENCES 63 APPENDIX 66

List of Figures

Figure No. Name of Figure Page No.

Fig 2.1: Cockcrof-Walton cascade voltage-doubler circuit 7 Fig 2.2: Dickson charge pump circuit 8 Fig 2.3: Karthaus-Fischer cascade voltage-doubler circuit. 8 Fig 2.4: Half wave voltage doubler circuit 10 Fig 2.5: Full wave voltage doubler circuit 12 Fig 2.6: Voltage tripler and quadrupler circuit 13 Fig 2.7: A simple voltage divider 16 Fig 3.1: Transformer and correction constructional view 17 Fig 3.2: Phasor diagram of transformer 18 Fig 3.3: Capacitor AC response and electrolyte capacitor respectively. 19 Fig 3.4: Phasor diagram of capacitor 19 Fig 3.5: Diode IN4007 20 Fig 3.6: Resistor and phasor diagram respectively 21 Fig 3.7: Potentiometer and circuit-diagram respectively 22 Fig 3.8: Pin diagram of Arduino Uno R3 23 Fig 3.9: The schematic diagram of Arduino Uno R3 25 Fig 3.10: Pin diagram of the microcontroller ATmega328P 26 Fig 3.11: GSM/GPS/GPRS module (SIM908 Kit) and pin diagram respectively 27 Fig 3.12: Voltage sensor module and pin diagram respectively 28 Fig 3.13: Temperature sensor (LM35) and pin diagram 29 Fig 3.14: Pin diagram and front view of LCD display (16*2) 30 Fig 3.15: Single channel opto isolated relay module and SPDT relay working 31 Fig 3.16: Block diagram of high voltage dc generation circuit using voltage multiplier with LCD display. 32 Fig 3.17: Block diagram monitoring system at wireless display terminal. 33 Fig 3.18: DC voltage measuring circuit 35 Fig 3.19: AC voltage measuring circuit 35 Fig 3.20: LM35 and Arduino interfacing 37

Fig 3.21: Single channel relay module connection 37 Fig 3.22: The simulation circuit diagram 39 Fig 3.23: The simulation result and waveform during device is in service. 41 Fig 3.24: Simulation result and waveform during over temperature protection is 42 activated. Fig 3.25: Wave shapes of input AC volt & output DC volt for 1st stage 43 Fig 3.26: Wave shapes of input AC volt & output DC volt for 2nd stage 43 Fig 3.27: Wave shapes of input AC volt & output DC volt for 3rd stage 44 Fig 3.28: Wave shapes of input AC volt & output DC volt for 4th stage 44 Fig 3.29: Wave shapes of input AC volt & output DC volt for 5th stage 44 Fig 3.30: Wave shapes of input AC volt & output DC volt for 6th stage 44 Fig 3.31: Wave shapes of input AC volt & output DC volt for 7th stage 45 Fig 3.32: Wave shapes of input AC volt & output DC volt for 8th stage 45 Fig 3.33: Wave shapes of input AC volt & output DC volt for 9th stage 45 Fig 3.34: Wave shapes of input AC volt & output DC volt for 10th stage 45 Fig 3.35: Wave shapes of input AC volt & output DC volt for 11th stage 46 Fig 3.36: Wave shapes of input AC volt & output DC volt for 12th stage 46 Fig 3.37: Wave shapes of input AC volt & output DC volt for 13th stage 46 Fig 3.38: Wave shapes of input AC volt & output DC volt for 14th stage 46 Fig 3.39: The simulation diagram shown the results of every stage DC output volt 47 for 55V AC input. Fig 4.1: Photograph of high voltage DC generating circuit 50 Fig 4.2: Photograph of the voltage divider circuit 51 Fig 4.3: High voltage DC generation circuit hardware prototype installation 51 Fig 4.4: First stage output 52 Fig 4.5: Second stage output 52 Fig 4.6: Third stage output 52 Fig 4.7: Fourth stage output 52 Fig 4.8: Fifth stage output 52 Fig 4.9: Sixth stage output 52 Fig 4.10: Seventh stage output 52

Fig 4.11: Eighth stage output 52 Fig 4.12: Ninth stage output 52 Fig 4.13: Tenth stage output 52 Fig 4.14: Eleventh stage output 52 Fig 4.15: Twelfth stage output 52 Fig 4.16: Thirteenth stage output 52 Fig 4.17: Fourteenth stage output 52 Fig 4.18: The LCD display of the developed system, showing different parameters 53 Fig 4.19: High voltage DC generation circuit trip massage in LCD display 53 Fig 4.20: The oscilloscope output waveform of input AC voltage and output DC 54 voltage of high voltage DC generation circuit. Fig 4.21: The oscilloscope output waveform of input AC voltage and output DC 55 voltage of high voltage DC generation circuit when device is tripped. Fig 4.22: Parameters, displaying in the PC screen 56 Fig 4.23: Running, alarm and tripping condition parameters in zoom view 56 Fig 4.24: Parameters of remote monitoring station. 60 Fig 5.1: Electricity generation coupled at DC micro bus with remote monitoring 62 station.

XII

List of Tables

Table No. Title Page No.

Table 3.1: Arduino specification table 24 Table 3.2: GSM/GPS/GPRS module specification table 27 Table 3.3: Simulation output DC voltage of each 14th stage for fixed 48 input AC voltage. Table 3.4: Simulation output DC voltage for variable input AC voltage of 14th 49 stages voltage multiplier circuit. Table 4.1: Laboratory tested DC voltage output for different input voltage. 57 Table 4.2: Laboratory tested DC voltage output for fixed input voltage at 58 different stages. Table 4.3: Comparison between ideal output DC voltage, simulation output DC 59 voltage and device output DC voltage Table 4.4: Shown the developed high voltage DC generating circuit input AC and 59 output DC voltage as shown in LCD screen.

XIII

List of Abbreviations

HVDC High Voltage Direct Current LCD Liquid Cristal Display HV High Voltage CW Cockcroft–Walton CRT Cathode Ray Tube EEPROM Electrically Erasable Programmable Read Only Memory PWM Pulse with Modulation ICSP In Circuit System Programming GSM Global System for Mobile Communication GPRS General Packet Radio Service GPS Global Positioning System SPDT Single Pole Double Throw

ISC Short circuit current PHP Hypertext Preprocessor

XIV

Chapter 1 Introduction

1.1 Overview

Power systems now a day consists of large scale complex structures which comply with various applications such as research work, bulk transmission of power, HV cable and electric breakdown strength testing, particle accelerators, lasers systems, x-ray systems, electron microscopes, photon multipliers, electrostatic systems are required for high voltage levels [1]. There are two basic approaches that are generally used to generate dc high voltage for high- voltage/low-current applications. Existing power supplies produces voltages lower than their requisite based on the energy sources or insulation limits. For this reason, there has been many ongoing research to produce a voltage greater than the supply voltage [2], [3]. This is usually achieved by step-up transformers, voltage doubler, multiplier circuits, charge pump circuits, switched-capacitor circuits, and boost or step-up converters [3]. Voltage multipliers are AC- to-DC power conversion devices, comprised of diodes and capacitors that produce a high potential DC voltage from a lower voltage AC source. Voltage multiplier circuits are widely used in many high-voltage/low-current applications besides, it has lesser voltage drop and faster transient response at start-up, when compared with conventional high voltage DC generation circuit [5]. High voltage DC is achieved by using the voltage multiplier circuits. Each stage is comprised of one diode and one capacitor. The half-wave series multiplier is most commonly used in this category [8]. On the other hand, data acquisition and processing plays an important role in the area of modern industry. System precision and performance is required depending on application. Real-time monitoring of electrical parameters is needed beside the high performance and precision of measurements with the development of modern industry towards networking [9].

The project is to designed and to develop a high voltage DC generation circuit using capacitors, diodes and 230V AC circuit with remote monitoring equipment and over

P a g e | 1 temperature protection. A ladder network connection using the capacitor and diodes is done for this voltage multiplier circuit. Low current and high voltage are the conditions developed using voltage multipliers. The electronic power meter is based on an Arduino from Microchip Technology Inc. PIC family, which help to monitor data through internet and after measuring the temperature if it is exceed the set value it will cut the power supply to protect the DC generation circuit. Main purpose of this project is to design and implement a Voltage multiplier that can produce a high voltage DC power supply from a single phase AC with remote interface and over temperature protection. The multiplication factor to 14 stages will produce an output within 1000 volt for safety reasons.

The hardware used in this project is meant for laboratory use even though we are to produce a high voltage DC power supply. This design can be used in industrial applications. Voltage doubler principle is also used in this project which is used to double the output voltage [9], [10]. The output of the voltage doubler is introduced into a series of cascaded circuit to generate a maximum of 1KV, however we could generate up to 10KV but due to safety concerns we will keep the maximum as low as possible [11].

1.2 Importance of high voltage in power system

High voltage DC power supplies meet a wide range of high performance demands. A high voltage power supply is a very useful source which can be effectively used in many applications like biasing of gas-discharge tubes, radiation detectors, electron microscopes, photon multipliers, metal cuttings, bio-medical field, industries, electrolysis process, electronic megger, laser guns, LCD backlighting, cameras, lighters, electric fencing, testing sparkplug also to check breakdown strength of transformer oil etc. Such a power supply could also be used for protection of property by electric charging of fences. Here the current requirement is of the order of a few micro amps.

In such an application, high voltage would essentially exist between wire and ground. When wire is touched, the discharge occurs via body resistance and it gives a non-lethal but

P a g e | 2 deterrent shock to an intruder. The circuit is built around a single transistorized blocking oscillator.

A simple series voltage multiplier is used to boost up this voltage in steps to give a final DC. The output voltage, however, is not very well regulated. But if there is a constant load, the final voltage can be adjusted by varying the supply voltage.

This project can be enhanced by increasing the number of stages and high voltages can be produced. The usage of transformers can be replaced by this circuit. This can be implemented very cheaply using diodes and capacitors. The circuit is also very simple and small that the disadvantages of bulky transformers can be eliminated and the voltage can be obtained very effectively and efficiently.

1.3 Motivation of this project

In the present scenario, there exists a huge demand for the production of high voltage, but unfortunately the conventional techniques are not meeting the current demand. Mostly transformers are being used for the production of high voltage AC which has to be rectified to DC. This method is both costly and bulky. Our project could be efficient both the ways. Here we are generating high voltage DC using a single phase AC with capacitors and diodes. With the increase in cascading very high voltages can be obtained. On the other hand, we implement remote monitoring systems which save time, increase work efficiency, help proactive maintenance and can help to minimize disruptions.

1.4 Objective of the project

The main objective of this project is to design and set up a high voltage DC generation circuit from single phase AC using voltage multiplier technique with long range remote interface.

P a g e | 3 The specific aims are summarized as follows:

 To design a high voltage DC generation circuit using simulation software (Proteus 8 Professional).  To implement the high voltage DC generation circuit practically in the laboratory and analyze the performance.  To design a voltage divider and GSM remote interfacing unit to monitor the parameters remotely and safely.  To design an over temperature and short circuit current protection for high voltage DC generation circuit.

1.5 Organization of the project

This project is organized as follows;

First chapter gives brief discussion of the introduction of the overall project.

Second chapter focuses on the literature & comprehensive review of high voltage DC generation circuit from single phase AC using voltage multiplier technique with remote interface.

Third chapter describe system design and simulation results and quantitative performance of the proposed methods in details.

Fourth chapter deals hardware implementation issues, experimental results and performance analysis of the developed system. Finally, fifth chapter summarizes the overall project outcome with conclusion and recommendations for future work.

P a g e | 4 Chapter 2 Literature review

2.1 Introduction

The Cockcroft–Walton (CW) generator or half wave voltage doubler is an electric circuit that generates a high DC voltage from a low-voltage AC or pulsing DC input. It was named after the British and Irish physicists John Douglas Cockcroft and Ernest Thomas Sinton Walton, who in 1932 used this circuit design to power their particle accelerator, performing the first artificial nuclear disintegration in history. They used this voltage multiplier cascade for most of their research, which in 1951 won them the Nobel Prize in Physics for "Transmutation of atomic nuclei by artificially accelerated atomic particles". Less well known is the fact that the circuit was discovered much earlier, in 1919, by Heinrich Greinacher, a Swiss physicist [2], [10]. For this reason, this doubler cascade is sometimes also referred to as the Greinacher multiplier. Cockcroft–Walton circuits are still used in particle accelerators. They also are used in everyday electronic devices that require high voltages.

2.2 Study of existing system

To generate a high voltage DC from a single phase AC using voltage multiplier circuit with remote interface, the theory and all application about CW voltage multiplier circuit has been studies and understanding make a research about circuit theory and the characteristic of each component to redesign the CW circuit. Later, some literature review will use to compare this project with previous experiment and related project for this title.

The buck–boost converter is a type of DC to DC converter that has an output voltage magnitude that is either greater than or less than the input voltage magnitude. It is equivalent to a fly-back using a single inductor instead of a transformer. Both of them can produce a range of output voltages, from an output voltage much larger (in absolute magnitude) than the input voltage, down to almost zero. Like the buck and boost converters, the operation of the buck-

P a g e | 5 boost is best understood in terms of the inductor’s” reluctance” to allow rapid change in current. From the initial state in which nothing is charged and the switch is open, the current through the inductor is zero. When the switch is first closed, the blocking diode prevents current from flowing into the right hand side of the circuit, so it must all flow through the inductor. However, since the inductor doesn’t like rapid current change, it will initially keep the current low by dropping most of the voltage provided by the source.

Over time, the inductor will allow the current too slowly increase by decreasing its voltage drop. The output voltage is of the opposite polarity than the input. This is a switch with a similar circuit topology to the boost converter and the buck converter. The output voltage is adjustable based on the duty cycle of the switching transistor. One possible drawback of this converter is that the switch does not have a terminal at ground; this complicates the driving circuitry. Neither drawback is of any consequence if the power supply is isolated from the load circuit (if, for example, the supply is a battery) because the supply and diode polarity can simply be reversed. The switch can be on either the ground side or the supply side.

A buck (step-down) converter combined with a buck (step-down) converter. The output voltage is typically of the same polarity of the input, and can be lower or higher than the input. Also during this time, the inductor will store energy in the form of a magnetic field. A study and design of a monitoring system for the continuous measurement of electrical energy parameters such as input voltage, output voltage and temperature. This system is designed to monitor the data over internet using Arduino Uno R3 and GSM/GPS/GPRS which also can be use PIC microcontroller, Raspberry Pi with Wi-Fi module [20]. The design takes into consideration the correct operation showing digital display is used to show the acquired measurements. A computer will remotely monitor the data over internet.

P a g e | 6 2.3 Conventional methods for high voltage DC generation

Voltage multiplier power supplies have been used for many years. Some of the most commonly applied methods for producing a voltage larger than the power supply voltage include step-up transformers, voltage doubler, multiplier circuits, charge pump circuits, switched-capacitor circuits, and boost or step-up converters. Among these methods, diode- capacitor topologies are more suitable [23].

In 1932, Cockcrof and Walton introduced a complex cascade voltage-doubler that is shown in Figure 2.1 [24] and they received the Nobel Prize in 1951 for this work. Tis circuit could produce a steady potential of about 700 kV that was three times greater than the applied input voltage. However, due to existence of series connected coupling capacitances, the high coupling voltage drop happens in this configuration. Tis phenomenon causes a small voltage gain for the circuit of Figure 2. Furthermore, series connected output capacitor causes a low output capacitance. In this circuit, except Cs1, other output capacitors were holding a ﬂoating voltage. Therefore, employing the stored electrical charge in each capacitor, individually, for other applications was complex.

Fig 2.1: Cockcrof-Walton cascade voltage-doubler circuit

In 1976, Dickson proposed a cascade diode-capacitor circuit, which was an improvement for the Cockcrof-Walton circuit (Figure 2.1) [25]. Tis circuit configuration, known as “charge pump,” required clock pulses as the input of the coupling capacitors. The presented topology of the Dickson circuit was simpler than the Cockcrof-Walton circuit. However, requiring the clock pulses can limit utilizing this circuit for high-voltage applications. Figure 2.2 shows the Dickson charge pump, which is a kind of cascade voltage- doubler.

P a g e | 7 Fig. 2.2: Dickson charge pump circuit

In 2003, Karthaus and Fischer have simplified and improved circuit of the Cockcrof- Walton (Figure 2.1) as shown in Figure 2.3. Tis improved circuit configuration was modifying the Dickson circuit [26] transformation. However, in Karthaus-Fischer cascade voltage- doubler, the clock pulses were eliminated, as the numbers of coupling and stray capacitors were reduced. Therefore, the essential requirements of the circuit became less than the Dickson circuit (Figure 2.2). Based on the achievement, the Karthaus Fischer circuit can even be utilized for high-voltage applications. In addition, the input impedance of the Cockcrof Walton circuit was reduced by changing the connection of the coupling capacitors, and its output capacitance is increased by using an independent grounded stray capacitor for each stage, in Karthaus-

Fischer circuit [23].

Fig 2.3: Karthaus-Fischer cascade voltage-doubler circuit.

P a g e | 8 The recent technological developments have made it possible to design a voltage multiplier that efficiently converts the low AC voltage into high DC voltage comparable to that of the more conventional transformer-rectifier-filter-circuit. The voltage multiplier is made up of capacitors and diodes that are connected in different configurations. Voltage multiplier has different stages. Each stage is made up of one diode and one capacitor. These arrangements of diodes and capacitors make it possible to produce rectified and filtered output voltage whose amplitude (peak value) is larger than the input AC voltage.

Based on the review, the existing cascade voltage doublers can produce an output voltage higher than the applied input voltage. Depending on the output voltage Cockcrof- Walton multipliers can be classified into three types:

2.3.1 Voltage doubler A voltage doubler is an electronic circuit which charges capacitors from the input voltage and switches these charges in such a way that, in the ideal case, exactly twice the voltage is produced at the output as at its input. The simplest of these circuits are a form of rectifier which take an AC voltage as input and outputs a doubled DC voltage

2.3.1.1 Half wave voltage doubler

As its name suggests, a half-wave voltage doubler is a voltage multiplier circuit whose output voltage amplitude is twice that of the input voltage amplitude. A half-wave voltage doubler drives the voltage to the output during either positive or negative half cycle. The half- wave voltage doubler circuit consists of two diodes, two capacitors, and AC input voltage source.

The input wave form, circuit diagram and output waveform is shown in Fig 2.1. Here, all through the positive half cycle, the forward biased D1 diode conducts and diode D2 will be in o off condition. In this time, the capacitor (C1) charges to VSmax (peak 2 voltage). All through the negative half cycle, the forward biased D2 diode conducts and D1 diode will be in off condition. In this time C2 will start charging.

P a g e | 9 By kirchoff’s voltage law, -Vsmax-Vc1+Vc2=0 (Outer loop)

Vc2=Vsmax+Vc1

=Vsmax+Vsmax (sine Vc1=Vsmax) =2Vsmax  twitch the maximum value of the 20 voltage of transformer

Throughout the next positive half cycle, D2 is at reversed biased condition (open circuited).

In this time C2 capacitor gets discharged through the load and thus voltage across this capacitor gets dropped. But when there is no load across this capacitor, then both the capacitors will be at charged condition. That is C1 is charged to VSmax and C2 is charged to 2VSmax. Throughout the negative half cycle, the C2 gets charged yet again (2VSmax). In the next half cycle, a half wave which is filtered by means of capacitor filter is obtained across the capacitor C2. Here, ripple frequency is same as the signal frequency. The DC output voltage of the order of 3 KV can be obtained from this circuit.

Fig 2.4: Half wave voltage doubler circuit

P a g e | 10 Advantages of half-wave voltage doubler: o High voltages are produced from the low input voltage source without using the expensive high voltage transformers. Disadvantages of half-wave voltage doubler o Large ripples (unwanted fluctuations) are present in the output signal.

2.3.1.2 Full wave voltage doubler

The full-wave voltage doubler consists of two diodes, two capacitors, and input AC voltage source.

During positive half cycle:

During the positive half cycle of the input AC signal, diode D1 is forward biased. So the diode D1 allows electric current through it. This current will flow to the capacitor C1 and charges it to the peak value of input voltage i.e. Vm.

On the other hand, diode D2 is reverse biased during the positive half cycle. So the diode D2 does not allow electric current through it. Therefore, the capacitor C2 is uncharged.

During negative half cycle:

During the negative half cycle of the input AC signal, the diode D2 is forward biased.

So the diode D2 allows electric current through it. This current will flow to the capacitor C2 and charges it to the peak value of the input voltage i.e. Vm.

On the other hand, diode D1 is reverse biased during the negative half cycle. So the diode

D1 does not allow electric current through it. Thus, the capacitor C1 and capacitor C2 are charged during alternate half cycles. The output voltage is taken across the two series connected capacitors C1 and C2.

If no load is connected, the output voltage is equal to the sum of capacitor C1 voltage and capacitor C2 voltage i.e. C1 + C2 = Vm + Vm = 2Vm. When a load is connected to the output terminals, the output voltage Vo will be somewhat less than 2Vm.

P a g e | 11 The circuit is called full-wave voltage doubler because one of the output capacitors is being charged during each half cycle of the input voltage.

Fig 2.5: Full wave voltage doubler circuit

P a g e | 12 2.3.2 Voltage tippler and quadrupler Using the method of extension of half-wave voltage doubler circuit, any voltage multipliers (Tripler, Quadrupler etc) can be created. When both the capacitor leakage and load are small, we can achieve tremendously high DC voltages by means of these circuits that include several sections to step-up (increase) the DC voltage.

Fig 2.6: Voltage tripler and quadrupler circuit

Here; all through the first positive and negative half cycle is same as that of half-wave voltage doubler. Throughout the next positive half cycle, D1 and D3 conducts and C3 charges to 2VSmax. Throughout the next negative half cycle, D2 and D4 conducts and C4 charges to

2VSmax. When more diodes and capacitors are added, every capacitor will get charged to

2VSmax. At the output; odd multiples of VSmax can be attained, if measured from the top of o transformer 2 winding and even multiples of VSmax can be attained, if measured from bottom of 2o winding of transformer.

P a g e | 13 2.4 Conventional methods for remote monitoring

The term wireless refers to the communication or transmission of information over a distance without requiring wires, cables or any other electrical conductors. The Communication is set and the information is transmitted through the air, without requiring any cables, by using electromagnetic waves like radio frequencies, infrared, satellite, etc., in a wireless communication network tropology.

At the end of the 19th century, the first wireless communication systems were introduced and the technology has significantly been developed over the intervening and subsequent years. Now a day the term wireless refers to a variety of devices and technologies ranging from smart phones to laptops, tabs, computers, printers, Bluetooth, etc.

In recent days, the wireless data transfer technology has become an integral part of several types of communication devices as it allows users to communicate even from remote areas. In our project we have used GSM/GPS/GPRS module (SIM900A Kit) and an Arduino [22]. By interfacing this two device we send data to a remote server which helps us, monitor real time values.

2.4.1 Key points of process

 Some conventional methods to send/receive for short distance (infrared, Bluetooth); medium distance (WiFi, Wmax) and long distance Um, satellite are used.  Read live data using C code base library from GSM/GPRS module (SIM908 Kit)  Save into MySQl Database  Write php code to display data into website  Host php site into php server with dedicated domain.  Browse site and read/check live device data

P a g e | 14 Device details:

This is a GPS/GPRS/GSM shield from DFRobot. This shield with a Quad-band GSM/GPRS engine works on frequencies EGSM 900MHz/DCS 1800MHz and GSM850 MHz/PCS 1900MHz. It is controlled via AT commands (GSM07.07 ,07.05 and SIMCOM enhanced AT Commands). And the design of this shield allows you to drive the GSM & GPS function directly with the computer and the Arduino Board. It includes a high-gain SMD antenna for GPS & GSM which send data to MySQL database.

MySQL Database:

A database is a collection of related data which is organized so that it can be manipulated, updated and stored very easily. MySQL is a database system used on the web, that runs on a server and is very fast, reliable, and easy to use standard SQL. MySQL compiles on a number of platforms is developed, distributed, and supported by Oracle Corporation. PHP + MySQL Database System combined with MySQL are cross-platform.

Hypertext Preprocessor (PHP):

PHP is a widely-used, open source scripting language. It is scripts are executed on the server and generate dynamic page content for create, open, read, write, delete, and close files on the server. PHP can collect form data, send and receive cookies, modify encrypt data in database to control user-access and runs efficiently on the server side.

2.5 Breakdown voltage

While the multiplier can be used to produce thousands of volts of output, the individual components do not need to be rated to withstand the entire voltage range. Each component only needs to be concerned with the relative voltage differences directly across its own terminals and of the components immediately adjacent to it. Typically, a voltage multiplier will be physically arranged like a ladder, so that the progressively increasing voltage potential is not given the opportunity to arc across to the much lower potential sections of the circuit.

P a g e | 15 Note that some safety margin is needed across the relative range of voltage differences in the multiplier, so that the ladder can survive the shorted failure of at least one diode or capacitor component. Otherwise a single-point shorting failure could successively over- voltage and destroy each next component in the multiplier, potentially destroying the entire multiplier chain.

2.6 Voltage divider A voltage divider is a simple circuit which turns a large voltage into a smaller one. Using just two series resistors and an input voltage, we can create an output voltage that is a fraction of the input. In electronics, a voltage divider (also known as a potential divider) is a passive linear circuit that produces an output voltage (Vout) that is a fraction of its input voltage (Vin). In fig 2.7 shown voltage divider, fig (a) is a simple voltage divider where fig (b) is another voltage divider with bridge rectifier.

aaaa

aasdddsc s

(a) (b)

Fig 2.7: A simple voltage divider

A voltage divider referenced to ground is created by connecting two electrical impedances in series, as shown in Fig 2.7. The input voltage is applied across the series impedances Z1 and Z2 and the output is the voltage across Z2. Z1 and Z2 may be composed of any combination of elements such as resistors, inductors and capacitors. If the current in the output wire is zero then the relationship between the input voltage, Vin, and the output voltage,

푍2 Vout, is: VOUT = VIN 푍1+ 푍2

P a g e | 16 Chapter 3

System design and simulation of high voltage DC

3.1 Theory of major components used

The design aims to generate high voltage DC from single phase AC which can be monitored in real time data at a local LCD along with remotely over internet. The overall system requires a single phase step down transformer, capacitors, diodes, resistors, Arduino, GSM module, voltage sensor & a temperature sensor.

3.2 Transformer

Fig. 3.1: Transformer and correction constructional view

P a g e | 17 The transformer that used in the project is centrifugal transformer. It has the input voltage capability of 230 V. The maximum current that draws by the transformer is 500 mA. This is a step down transformer. The three terminals of the transformer are (6-0-6). The output voltage of the transformer is 54.23 V. There are many sizes, shapes and configurations of transformers from tiny to gigantic like those used in power transmission. Some come with stubbed out wires, others with screw or spade terminals, some made for mounting in PC boards, others for being screwed or bolted down. The faster the voltage changes, the higher the frequency. The transformer phasor diagram is shown below in Fig. 3.2

Fig. 3.2: Phasor diagram of transformer

If we are given currents, IS and Io, we can calculate the primary current, IP by the following methods. Horizontal components, Ix=I0 sin + I1 sin and Vertical components, IY=I0 cos + I1 cos. Transformers can be built so they have the same number of windings on primary and secondary or different numbers of windings on each. If they are the same, the input and output voltage are the same and the transformer is just used for isolation so there is no direct electrical connection (they are only linked through the common magnetic field). If there are more windings on the primary side than the secondary side, then it is a step down transformer. If there are more windings on the secondary side, then it is a step up transformer.

P a g e | 18

3.2 Capacitors A basic capacitor has two parallel plates separated by an insulating material. A capacitor stores an electrical charge between the two plates. The unit of capacitance is Farads (F). It has different capacitance with different voltage ratings withstand temperature up to 85- degree C.

Fig 3.3: Capacitor AC Response and electrolyte capacitor respectively.

Fig 3.4: Phasor diagram of capacitor

In this proposed project, the size of capacitors used in multiplier circuit is directly proportional to the frequency of input signal. Capacitors used in off line, 50 Hz applications;

P a g e | 19 say 10 kHz are typically the range in different microfarad according to market availability. The voltage rating of capacitor must be capable of numbers of staged used. A good thumb rule is to select capacitor whose voltage rating is approximately twice that of actual peak applied voltage. For example, a capacitor which will see a peak voltage of 2E should have a voltage rating of approximately 4E.

3.3 Diodes The diode used in the project is IN4007.It is used in order to withstand the reverse voltage. High surge current capability. Low for voltage forward drop. It is the simplest semiconductor device. It is a nonlinear one. Mostly used in power supplies. It is also work as voltage limiting circuits. A rectifier diode is used as a one-way check valve. Since these diodes only allow electrical current to flow in one direction, they are used to convert AC power into DC power. When constructing a rectifier, it is important to choose the correct diode for the job; otherwise the circuit may become damaged. Luckily, a 1N4007 diode is electrically compatible with other rectifier diodes, and can be used as a replacement for any diode in the 1N4007 family.

Fig. 3.5: Diode IN4007

Reverse breakdown voltage: A diode allows electrical current to flow in one direction from the anode to the cathode. Therefore, the voltage at the anode must be higher than at the cathode for a diode to conduct electrical current. In theory, when the voltage at the cathode is

P a g e | 20 greater than the anode voltage, the diode will not conduct electrical current. Some diodes such as the 1N4007 will break down at 50 V or less. The 1N4007, however, can sustain a peak repetitive reverse voltage of 1000 V.

Forward current: When the voltage at the anode is higher than the cathode voltage, the diode is said to be “forward-biased,” since the electrical current is “moving forward.” The maximum amount of current that the diode can consistently conduct in a forward-biased state is 1 ampere. The maximum that the diode can conduct at once is 30 A.

Forward voltage and power dissipation: When the maximum allowable consistent current amount is flowing through the diode, the voltage differential between the anode and the cathode is 1.1 V. Under these conditions, a 1N4007 diode will dissipate 3 watts of power (about half of which is waste heat).

3.4 Resistor:

Resistors are common elements of electrical networks and electronic circuits and are ubiquitous in electronic equipment. Practical resistors as discrete components can be composed of various compounds and forms. Resistors are also implemented within integrated circuits. The electrical function of a resistor is specified by its resistance: common commercial resistors are manufactured over a range of more than nine orders of magnitude. The nominal value of the resistance falls within the manufacturing tolerance, indicated on the component. In this project we used resistor due to voltage divider purpose.

Fig 3.6: Resistor and phasor diagram respectively

P a g e | 21 Working of Resistor: The working of a resistor can be explained with the similarity of water flowing through a pipe. Consider a pipe through which water is allowed to flow. If the diameter of the pipe is reduced, the water flow will be reduced. If the force of the water is increased by increasing the pressure, then the energy will be dissipated as heat. There will also be an enormous difference in pressure in the head and tail ends of the pipe. In this example, the force applied to the water is similar to the current flowing through the resistance. The pressure applied can be resembled to the voltage.

3.4.1 Potentiometer

A variable resistor is the type of resistor which changes the flow of current in a controlled manner by offering a wide range of resistances. As the resistance increases in the variable resistor the current through the circuit decreases and vice versa. They can also be used to control the voltage across devices in a circuit too. Therefore, in applications where current control or voltage control is needed, these type of resistors come handy. Fig. 3.9 shows some real life variable resistors.

Fig 3.7: Potentiometer and circuit diagram respectively

Working Principle and Construction: A typical variable resistor has 3 terminals. Out of the three, two are fixed terminals at the ends of a resistive track. the position of this terminal on the resistive track that decides the resistance of the variable resistor. These resistors offer a different resistance value, which means their resistance values can be adjusted to different values so as to provide the necessary control of current and voltage.

P a g e | 22 3.5 Arduino-uno-R3

Microcontroller used for our project is Arduino Uno R3. The R3 is the third, and latest, revision of the Arduino Uno. The Arduino Uno is a microcontroller board based on the ATmega328. The ATmega328 has 32 KB (with 0.5 KB occupied by the boot loader). It also has 2 KB of SRAM and 1 KB of EEPROM (which can be read and written with the EEPROM library). It has 20 digital input/output pins (of which 6 can be used as PWM outputs and 6 can be used as analog inputs), a USB connection, a power jack, an in-circuit system programming (ICSP) header, and a reset button. It is simply connected to a computer with a USB cable. Pin diagram Arduino Uno board is shown in Fig 3.8.

Fig 3.8: Pin diagram of Arduino Uno R3

The Vin is the input voltage to the Arduino board when it's using an external power source (as opposed to 5 V from the USB connection or other regulated power source). The 5 V pin outputs a regulated 5V from the regulator on the board. The microcontroller board can be supplied with power either from the DC power jack (7 – 12 V), the USB connector (5 V), or the Vin pin of the board (7-12 V). Supplying voltage via the 5 V or 3.3 V pins bypasses the regulator, and can damage your board. So it is advised not to do so. Maximum current draw is 50 mA. An Arduino board is based on a AVR microcontroller chip and when the board with

P a g e | 23 nothing wired or attached to it consumes around 80 mA of 5 V current. The Clock speed of the Arduino is 16 MHz so it can perform a particular task faster than the other processor or controller.

Table 3.1: Arduino specification table

Specification Table:

Microcontroller ATmega328P Operating Voltage 5 V Input Voltage 7-12 V (recommended) Input Voltage (limit) 6-20 V Digital I/O Pins 14 (of which 6 provide PWM output) PWM Digital I/O Pins 6 Analog Input Pins 6 DC Current per I/O Pin 20 mA DC Current for 3.3V Pin 50 mA Flash Memory 32 KB (ATmega328P) of which 0.5 KB used by boot loader SRAM 2 KB (ATmega328P) EEPROM 1 KB (ATmega328P) Clock Speed 16 MHz LED_BUILTIN 13 Length 68.6 mm

P a g e | 24 The schematic diagram of Arduino Uno R3 board and pin diagram of the microcontroller ATmega328P are shown in Fig. 3.9 and fig. 3.10 respectively.

Fig. 3.9: The schematic diagram of Arduino Uno R3

P a g e | 25

Fig 3.10: Pin diagram of the microcontroller ATmega328P

3.6. GSM/GPS/GPRS module

GPS/GPRS/GSM shield from DFRobot with a Quad-band GSM/GPRS engine works on frequencies EGSM 900MHz/DCS 1800MHz and GSM850 MHz/PCS 1900MHz. It also supports GPS technology for satellite navigation. It's possible for your robot and control system to send messages and use the GSM network. t is controlled via AT commands (GSM07.07 ,07.05 and SIMCOM enhanced AT Commands). And the design of this shield allows you to drive the GSM & GPS function directly with the computer and the Arduino Board. It includes a high-gain SMD antenna for GPS & GSM as shown in fig 3.11. The specification table of GSM/GPS/GPRS module shown in table 3.2.

P a g e | 26

Fig 3.11: GSM/GPS/GPRS module (SIM908 Kit) and Pin diagram respectively

Table 3.2: GSM/GPS/GPRS module specification table

Specification table:

GSM/GPS/GPRS module SIM908 Kit Power supply 6-12 V@ 2 A Low power consumption 100 mA @ 7 V - GSM mode Quad-Band 850/900/1800/1900MHz GPRS multi-slot Class 10 Support GPS technology Satellite navigation Embedded high-gain SMD antennas GPS & GSM Directly support 4*4 button pad USB/Arduino control With switch Board Surface Immersion gold Size 81x70mm

P a g e | 27 3.7 Voltage sensor

The Arduino analog input is limited to a 5 VDC input. If you wish to measure higher voltages, you will need to resort to another means. One way is to use a voltage divider. The Voltage sensor can detect the supply voltage from 0.0245V to 25V. This module is based on resistor divider principle. This module allows the input voltage to reduce 5 times. As the Arduino or microcontroller analog input voltage is normally maximum 5V, the input voltage of this module cannot exceed 5Vx5 which is 25V. If you give 25V DC to Vin, you will get 5V output in the 'Sig' pin. It is fundamentally a 5:1 voltage divider using a 30K and a 7.5K Ohm resistor. We are restricted to voltages that are less than 25 volts. More than that and it will exceed the voltage limit of your Arduino input.

Fig 3.12: Voltage Sensor module and pin diagram respectively

P a g e | 28 3.8 LM35 Temperature Sensor

The LM35 series are precision integrated-circuit temperature sensors, whose output voltage is linearly proportional to the Celsius (Centigrade) temperature. This temperature sensor calibrated directly in ° Celsius (Centigrade), linear + 10.0 mV/°C scale factor. 0.5°C accuracy guarantee able (at +25°C) and rated for full −55° to +150°C range

Fig. 3.13: Temperature sensor (LM35) and pin diagram

3.9. LCD Display

A Liquid crystal display (LCD) is a flat display that uses the light modulating properties of liquid display. LCDs are available to display arbitrary images (as in a general-purpose computer display) or fixed images with low information content, which can be displayed or hidden, such as preset words, digits, and 7-segment displays, as in a digital clock. They use the same basic technology, except that arbitrary images are made up of a large number of small pixels, while other displays have larger elements. A (16x2) LCD panel consists of 16 columns and 2 rows. It can show up to 16 characters in 2 lines

The LCD screen is more energy efficient and can be disposed of more safely than a CRT. Its low electrical power consumption enables it to be used in battery power electronic equipment. Liquid crystal were first discovered in year 1888. The photograph of LCD PIN diagram, front view and back view shown in Fig 3.20; Fig 3.21 and Fig 3.22 respectively.

P a g e | 29

Fig 3.14: Pin diagram and front view of LCD display (16*2)

Pin Description:  Pin 7 to pin 14-All 8 pins are responsible for the transfer of data.  Pin 4-This is RS i.e., register select pin.  Pin 5-This is R/W i.e., Read/Write pin.  Pin 6-This is E i.e., enable pin.  Pin 2-This is VDD i.e., power supply pin.  Pin 1-This is VSS i.e., ground pin.  Pin 3-This is short pin

P a g e | 30 3.10 Relay

The standard single channel 12 V, 30 A opto isolated relay module using of high-level voltage signals to trigger, only needs 3 mA current signal to drive the 30 A load relay. Use of high-quality power relay, high-withstand voltage transistor, red & green signal lights assures accurate and stable performance. Can be used in various types of power control occasions.

Fig 3.15: Single channel opto isolated relay module and SPDT relay working

Relay is an electromagnetic switch, which is controlled by small current, and used to switch ON and OFF relatively much larger current. Means by applying small current we can switch ON the relay which allows much larger current to flow. A relay is a good example of controlling the AC (alternate current) devices, using a much smaller DC current. Commonly used Relay is Single Pole Double Throw (SPDT) relay, it has five terminals as shown in above figure 3.15.

When there is no voltage applied to the coil, COM (common) is connected to NC (normally closed contact). When there is some voltage applied to the coil, the electromagnetic field produced, which attracts the Armature (lever connected to spring), and COM and NO (normally open contact) gets connected, which allow a larger current to flow. Relays are available in many ratings, here we used 5 V operating voltage relay, which allows 7 A-250 VAC current to flow. For this project we have used 5 V Relay module.

P a g e | 31 3. 11 Block diagram of the proposed system

The proposed high voltage DC generating system with wireless monitoring feature can be divided into part: First part is the high voltage DC generating system with LCD monitor as shown in Fig. 3.16 and Second part is PC based monitor at the wireless display terminal as shown in Fig. 3.17.

Diode & Capacitors Voltage Doubler Relay In Circuit Ladder Networks AC Supply

Cascade Temp. Sensor Circuit

Arduino Uno R3

Voltage Potential Divider Sensor 236:1

LCD Display

Fig 3.16: Block diagram of high voltage dc generation circuit using voltage multiplier with LCD display.

P a g e | 32

Fig 3.17: Block diagram monitoring system at wireless display terminal.

The DC generator comprises of 3 parts. (1) Diode and Capacitor in Ladder Network (2) Voltage Doubler Circuit (3) Cascade Circuit. The Diode and capacitor converts the AC supply to DC. The output voltage is doubled using the voltage doubler and circuit is further multiplied by cascade circuit to produce output voltage of 1 KV DC output. A temperature sensor senses the temperature of the cascade circuit and sends to the Arduino Uno R3 to show on the LCD display and give feedback to the relay for over temperature protection of the capacitor bank. The voltage sensor senses the output voltage through a potential divider which scales down the output voltage within the sensing range. The voltage is displayed on the LCD display using the Arduino Uno R3.

On the other hand, to monitor the output using PC monitor terminal, the Arduino Uno R3 is connected to a GSM/GPRS module, which sends data to a server. The server stores the data continuously which is displayed through a PC. The PC shows the parameter and shows the trip signal feedback in computer screen through web browser. This data can be monitored from any location through the internet.

P a g e | 33 3.12 Voltage measuring system

It is not possible to measuring high voltage DC through Arduino without changing the higher voltage range. Arduino analog inputs can be used to measure DC voltage between 0 and 5 V (on 5 V Arduino such as the Arduino Uno when using the standard 5 V analog reference voltage). The range over which the Arduino can measure voltage can be increased by using two resistors to create a voltage divider. The voltage divider decreases the voltage being measured to within the range of the Arduino analog inputs. The voltage sensor is used to measure voltage for Arduino within its range. The Sensor Unit takes two inputs, DC voltage and AC voltage. The Sensor Unit scales down the input DC and AC voltages into a DC voltage in the range of 0 to 5 V and provides the same as output.

The Processor Unit takes input voltage in the range of 0 to 5 V. This unit takes the Sensor Unit’s output as input voltage and uses the ADC to read this voltage. An Algorithm is then applied to calculate the voltage. The unit then sends a 4bit data to the Display Unit which includes the AC and DC voltage values.

AC/DC Voltage Sensor Unit: A basic voltage divider circuit is used as the AC/DC Sensing Unit to scale down the input DC and AC voltages into a DC voltage in the range of 0 to 5 V. The Processor Unit can read this scaled down voltage and calculate the actual AC/DC voltages.

Design the value of R1: Let us consider maximum voltage that could be measured as 500 V.

When we apply 500V as ‘V’, the ‘V2’ should not be more than 5 V and hence ‘V1’ will be 500 – 5 = 495 V. At very high voltages like 495 V, the first thing to be taken care of is the power rating of the resistor. We are using resistors with the power rating 5 W, and the power consumed by the resistor ‘R1’ should be less than this, otherwise the resistors get heated up and catch fire. 2 The equation for power is, P = V1 / R1. Where;

P = Power rating of the resistor V = Voltage across the resistor R = Resistance of the resistor

P a g e | 34 For the resistor R1 with power rating 5 W and 495 V across it,

0.25 = 495 * 495 / R1

Or, R1 = 980100 ohms, take 1 M ohm standard resistor.

Design the value of R2:

Now the value of R2 can be calculated using the previous equation, V = V2 * (1 + R1 / R2) as follows;

R2 = R1 / ((V / V2) – 1)

R2 = 1000000 / ((500 / 5) – 1)

R2 = 10101 ohms, take 10 K ohm standard resistor.

DC voltage as input:

R1 V1

V2 R2

Fig 3.18: DC voltage measuring circuit

The voltage ‘V2’ is a fraction of the actual applied voltage ‘V’. The applied voltage ‘V’ can be calculated from the fraction of applied voltage ‘V2’ with the help of the following equation.

DC voltage, V dc = V2 * (1 + (R1 / R2))

AC voltage as input:

R1 V1

R2 V2

Fig 3.19: AC voltage measuring circuit

P a g e | 35 When we are applying an AC voltage we use a rectifier diode in series with the Voltage divider circuit to prevent the negative cycles from entering the circuitry. No need for step down transformers because we are already getting a voltage ‘V2’ in the range of 0 to 5 V only, across

R2.

Requirement for Range selector: We require multiple ranges in a voltmeter due to the error appears in readings because of resistance tolerance. a) Decrease in the ratio of R1/ R2 decreases the error b) There is a limit beyond which the R1/ R2 cannot decrease further:

To measure different values of V with minimum error we need different set of R1 with a common R2. The voltage V whose value need to be measured is connected with an R1 which gives the least ratio of R1/ R2, taking care of the fact that V2 should not go above 5 V range.

(R1 / R2) > (V / 5) – 1

For example, to measure V = 500V, R1 / R2 > 99, hence we can use the set R1 = 1M and R2 =

10K which gives R1 / R2 = 100.

3.13 Temperature measuring system

Measuring temperature of a place through Arduino is easy by using any of the commercial temperature sensor. We are going to measure the temperature using low cost and efficient LM35 analog output temperature sensor with Arduino. LM35 is three terminal linear temperature sensor from National semiconductors. LM35 output voltage is proportional to centigrade/Celsius temperature. LM35 Celsius/centigrade resolution is 10 mV. 10 mills volt represent one degree centigrade/Celsius. So if LM35 outputs 100 mV the equivalent temperature in centigrade/Celsius will be 100/10 = 10 centigrade/Celsius. Lm35 can measure from -50 degree centigrade/Celsius up to 150 degrees centigrade/Celsius. It gives a voltage signal that is actually the temperature of the particular place. The voltage output of the LM35 increases 10 mV per degree Celsius rise in temperature. LM35 can be operated from a 5 V

P a g e | 36 supply and the stand by current is less than 60 u A. The pin out of LM35 is shown in the figure below.

Fig 3.20: LM35 and Arduino interfacing

3.14 Over temperature protection system

This temperature protection system consists of various components like Arduino, LCD display, relay, and thermistor. The working mainly depends on the relay and thermistor as the temperature increased the relay will be turned on through Arduino and if the temperature decreased below the preset value then Relay will be turned off. The whole triggering process and temperature value setting is performed by the programmed Arduino Uno. It also gives us details about the change in temperature status in every moment on the LCD screen.

The analog pin (A3) is used to check the voltage of thermistor pin at every moment and after the calculation using Stein-Hart equation through the Arduino code we are able to get the temperature and send a signal to relay for switching high to low.

Fig 3.21: Single channel relay module connection

P a g e | 37 As the temperature increases more than set value Arduino makes the Relay Module Turned On by making the pin X HIGH (where the Relay module is connected) when the temperature goes below 40 Degree Arduino turns off the Relay Module by making the Pin LOW. High voltage generation circuit will also turn on and off according to Relay module.

3.15 Short circuit current (Isc) protection system

Arduino algorithm is used as short circuit current (ISC) protection. If the device temperature rises due to short circuit, the current will become high and device output voltage will decrease trend to zero. By this time device temperature will increase rapidly. By the help of over temperature protection circuit, Arduino makes the Relay Module Turned On by making the pin X HIGH. Thus the way device is able to give protection against Isc.

3.16 Final simulation

To design the HVDC generation circuit transformer, diode, capacitors are used. To protect to circuit from over temperature we use relay controlled by Arduino. Transformer is used to step down the input voltage then the diode capacitor cascade precision rectifier is used to convert to HVDC. The simulation circuit diagram is shown in Fig 3.22.

P a g e | 38 RL1 5V C1 C3 C5 C7 C9 C11

470uF 100uF 22uF 4.7uF 2.2uF 2.2uF C13 2.2uF V1 VSINE D1 D2 D3 D4 D5 D6 D7 D8 D9 D10 D11 D12

1N4007 1N4007 1N4007 1N4007 1N4007 1N4007 1N4007 1N4007 1N4007 1N4007 1N4007 1N4007

C2 C4 C6 C8 C10 C12

220uF 47uF 10uF 2.2uF 2.2uF 2.2uF

C D13 Q1 1N4007 D R5 C14 2.2uf R1(2) 1N4007 1k1 R1 V=885.142 D14 3M LCD2 2N2222 LM016L

1 U1 C17 32.0 100u U1(VOUT)

S 2 V=0.321878 E

S VOUT W

D ARD1 D

1 3 LM35 R3

N 30900R R

BR1 B

. AREF

G D16(K) h 13

e e PB5/SCK V=2.66802 12

E C15 R4 n PB4/MISO

u n 11 100u 1080R ~ PB3/MOSI/OC2A

i g

n 10

i ~ PB2/OC1B

o D16 n 9 ~ PB1/OC1A

1N4733A U 8

e PB0/ICP1/CLKO

1 U

A BRIDGE i

- 1 7

g PD7/AIN1

2 L 6

A0 A ~ PD7/AIN1

G G 5

PC0/ADC0 r

~ PD5/T1/OC0B

A1 o

M N 4

PC1/ADC1 T

j A2 A PD4/T0/XCK PC2/ADC2 e 3

C16(1) c ~ PD3/INT1/OC2B A3 2 PC3/ADC3 t PD2/INT0 V=2.93933 A4 s PC4/ADC4/SDA 1 RXD . PD1/TXD

A5 c R2 PC5/ADC5/SCL 0 10k o PD0/RXD TXD C16 D15 m 1u RTS 1N4733A GENUINO UNO CTS Fig 3.22: The simulation circuit diagram

To generate high DC voltage, 55 V AC input is used by using step down transformer. A relay is used which operate with Arduino signal, when capacitor temperature gets higher than the set value. When diode capacitor cascade circuit put into operation, during the first positive half cycle of the input AC signal, the diode D1 is forward biased whereas diodes D2, D3 and D4 are reverse biased. Hence, the diode D1 allows electric current through it. This current will flow to the capacitor C1 and charges it to the peak value of the input voltage I.e. Vm. During the first negative half cycle, diode D2 is forward biased and diodes D1, D3 and D4 are reverse biased. Hence, the diode D2 allows electric current through it. This current will flow to the capacitor C2and charges it. The capacitor C2 is charged to twice the peak voltage of the input signal (2Vm). This is because the charge (Vm) stored in the capacitor C1 is discharged during the negative half cycle. Therefore, the capacitor C1 voltage (Vm) and the

P a g e | 39 input voltage (Vm) is added to the capacitor C2 I.e Capacitor voltage + input voltage = Vm + Vm = 2Vm. As a result, the capacitor C2 charges to 2Vm.

During the second positive half cycle, the diode D3 is forward biased and diodes D1, D2 and D4 are reverse biased. Diode D1 is reverse biased because the voltage is negative due to charged voltage Vm, across C1 and, diode D2 and D4 are reverse biased because of their orientation. As a result, the voltage (2Vm) across capacitor C2 is discharged. This charge will flow to the capacitor C3 and charges it to the same voltage 2Vm. During the second negative half cycle, diodes D2 and D4 are forward biased whereas diodes D1 and D3are reverse biased. As a result, the charge (2Vm) stored in the capacitor C3 is discharged. This charge will flow to the capacitor C4 and charges it to the same voltage (2Vm). The capacitors C2 and C4 are in series and the output voltage is taken across the two series connected capacitors C2 and C4. The voltage across capacitor C2 is 2Vm and capacitor C4 is 2Vm. So the total output voltage is equal to the sum of capacitor C2 voltage and capacitor C4 voltage I.e. C2 + C4 = 2Vm + 2Vm = 4Vm. In this way the increase in diode capacitor stages, connected in series, ultimately increase the output voltage. Therefore, the total output voltage obtained is XVm, where X is the number of diode capacitor stages. For displaying the parameters in LCD through Arduino it is required to maintain Arduino readable voltage range. To meet the Arduino readable sensor voltage range, we use voltage divider. Finally, Arduino send signals which help to display the input voltage, output voltage and device temperature.

Then input AC voltage, output DC voltage and device temperature are measured by Arduino (ATmega328P microcontroller). In the simulation we use resistor R1as a load to show charging and discharging phenomenon and convert pulsating dc to pure dc by adding capacitor C17 as filter.

The complete simulation diagram with results of a single phase ac to high voltage dc generation circuit using voltage multiplier with over temperature protection is shown in two different pictures in Fig 3.23, the LCD display shows the parameter and the oscilloscope shows input AC voltage and output DC voltage in waveforms, when the generation circuit is in service.

P a g e | 40

Fig. 3.23: The simulation result and waveform during device is in service.

When the over temperature protection relay acts in generation circuit, it cuts the input AC supply and saves the generation circuit from overheating; It can be seen in the LCD display and in oscilloscope as shown in Fig 3.24,

P a g e | 41

Fig. 3.24: Simulation result and waveform during over temperature protection is activated.

The comparison waveform of each stage of diode capacitor cascade circuit are different for the odd and even stage and almost symmetric for themselves. The output voltage produced by a half wave rectifier is not constant; it varies with respect to time. In practical applications, a constant DC supply voltage is needed.

The odd stage capacitors are cupping each other which charging and discharging with sinewave without rectification that’s why the output waveform is sinusoidal. For the even stage it will rectify by both connected diode and send rectified charge to capacitor and in capacitor even side the ground is connected that’s why output form comes DC waveform for the simulation. Without ground simulation can’t be possible.

P a g e | 42 A filter converts the pulsating direct current into pure direct current. In half wave rectifiers, a capacitor or inductor is used as a filter to convert the pulsating DC to pure DC. In order to produce a constant DC voltage, we need to suppress the ripples of a DC voltage. This can be achieved by using either a capacitor filter or inductor filter at the output side. In the below circuit, we are using the capacitor filter. The capacitor placed at the output side after 14th stage to smoothen the pulsating DC to pure DC. The Oscilloscope Output wave form at different stages of high voltage DC generation circuit are shown Fig. 3.25 to Fig. 3.39 respectively. Input AC voltage and output DC voltage waveform cooler are yellow and blue respectively.

Output DC Output DC

Input AC Input AC

Fig 3.25: Wave shapes of input AC volt & Fig 3.26: Wave shapes of input AC volt & output DC volt for 1st stage output DC volt for 2nd stage

P a g e | 43 Output DC Output DC

Input AC Input AC

Fig 3.27: Wave shapes of input AC volt & Fig 3.28: Wave shapes of input AC volt & rd output DC volt for 3 stage output DC volt for 4th stage

Output DC Output DC

Input AC Input AC

Fig 3.29: Wave shapes of input AC volt & Fig 3.30: Wave shapes of input AC volt & output DC volt for 5th stage output DC volt for 6th stage

P a g e | 44 Output DC Output DC

Input AC Input AC

Fig 3.31: Wave shapes of input AC volt & Fig 3.32: Wave shapes of input AC volt & output DC volt for 7th stage output DC volt for 8th stage

Output DC Output DC

Input AC Input AC

Fig 3.33: Wave shapes of input AC volt & Fig 3.34: Wave shapes of input AC volt & output DC volt for 9th stage output DC volt for 10th stage

P a g e | 45 Output DC Output DC

Input AC Input AC

Fig 3.35: Wave shapes of input AC volt & Fig 3.36: Wave shapes of input AC volt & output DC volt for 11th stage output DC volt for 12th stage

Output DC Output DC

Input AC Input AC

Fig 3.37: Wave shapes of input AC volt & Fig 3.38: Wave shapes of input AC volt & output DC volt for 13th stage output DC volt for 14th stage

P a g e | 46 In the bellow simulation after every stage we add voltage probe to know the output DC voltage for each 14th stage. The simulation diagram shown the results of every stage DC output voltage for 55 V AC input shown in Fig 3.39, the LCD display shows the parameter showing the input AC voltage and 14th stage DC output voltage, when the generation circuit is in service.

Fig 3.39: The simulation diagram shown the results of every stage DC output volt for 55V AC input.

P a g e | 47 In order to check of our developed simulation, we conduct experiments two different ways. Firstly, we measured the output DC voltage for each 14th stage of high voltage DC generation circuit and secondly we change the input AC voltage for ten different steps and take reading for generated different output DC voltage as final output DC voltage. This two data comparison are shown in Table 3.3 and Table 3.4 respectively.

Table 3.3: Simulation output DC voltage of each 14 stages for fixed input AC voltage.

SI. No. Number of Input AC voltage Simulation Output Device temperature Stage DC voltage 1 1st Stage 55 73.58 30.3o C

2 2nd Stage 55 154.23 30.3o C

3 3rd Stage 55 231.92 30.3o C

4 4th Stage 55 308.78 30.3o C

5 5th Stage 55 385.56 30.3o C

6 6th Stage 55 460.27 30.3o C

7 7th Stage 55 537.23 30.3o C

8 8th Stage 55 605.20 30.3o C

9 9th Stage 55 682.29 30.3o C

10 10th Stage 55 738.50 30.3o C

11 11th Stage 55 813.12 30.3o C

12 12th Stage 55 861.30 30.3o C

13 13th Stage 55 952.05 30.3o C

14 14th Stage 55 1048 30.3o C

P a g e | 48

Table 3.4: Simulation output DC voltage for variable input AC voltage of 14th stages voltage multiplier circuit.

SI. No. Input AC Voltage Simulation Output DC Device Temperature Voltage

1 10 196 30o C 2 15 285 30o C 3 20 368 30o C

4 25 463 30o C 5 30 587 30o C 6 35 683 30o C 7 40 768 30o C 8 45 865 30o C

9 50 966 30o C

o 10 55 1048 30 C

P a g e | 49 Chapter 4 Hardware development and performance analysis of high voltage DC

4.1 Developed hardware

The proposed system described in chapter 3 is implemented in a vero board and a breadboard. The photograph of the developed high voltage DC generating diode capacitator cascade circuit system is shown in Fig 4.1

Fig 4.1: Photograph of high voltage DC generating diode capacitator cascade circuit

After generating high voltage DC with diode capacitator cascade circuit we found the voltage range above 1K which is not measurable by conventional voltmeter. To measure the voltage for Arduino voltage sensor range (0.0245 V to 25 V) we use to divided voltage by voltage divider circuit. The photograph of the developed voltage divider circuit is shown in Fig 4.2

P a g e | 50

Voltage divider

Voltage divider with bridge rectifier.

Fig 4.2: photograph of the voltage divider circuit

The developed system is connected and tested in prototype method. Here we generate the high voltage DC from single phase AC supply. In the generating device we connected a temperature sensor, which sense the temperature and send it to Arduino for tripping the input AC supply. The photograph is showing the prototype arrangement in Fig. 4.3

Diode capacitator cascade circuit

Transformer

Arduino & GPRS module Relay

Voltage divider circuit divider Voltage

Voltage Voltage sensors

16*2 LCD LM35

Fig. 4.3: High voltage DC generation circuit hardware prototype installation.

P a g e | 51 In order to test the performance of our developed system, we conduct experiments in laboratory environment. We measured the output DC voltage of high voltage DC generation circuit for every single stage. We have generated the output voltage for same 55 V AC inputs, are shown in table 4.4 to 4.17 respectively.

P a g e | 52 When the generating circuit is connected to the supply, it will generate high voltage DC and the algorithm loaded in Arduino will help to monitor, compare the temperature and send the signal; which shown continuously in LCD display. The photograph is an example of such an LCD display, as shown in Fig. 4.18

Fig. 4.18: The LCD display of the developed system, showing different parameters.

When device temperature excites the set value it will trip the device and send the massage to LCD display. The photograph with trip massage is shown in Fig 4.19.

Fig 4.19: HVDC generation circuit trip massage in LCD display

P a g e | 53 As per design scheme if the device temperature become high and cross the set limit/value the device will be trip and save the circuit. Ensuring this device safety issue we add another protection (in Arduino algorithm) as short circuit current (ISC) protection. If the device temperature rises due to short circuit the device output voltage will decreasing trend to zero, it will also trip the device. After act the protection scheme we can differentiate the over temp or short circuit current protection by looking at the voltage and temperature values. If over temperature protection act device will directly tripped from higher voltage value, on the other hand if device tripped due short circuit current protection first voltage will be in decreasing trend to zero, then the temp become high and tripped the HVDC generation circuit. If device tripped due short circuit current protection it will be shown in the LCD display. Thus the device is able to give protection against over current or short circuit current (Isc).

The experimental Oscilloscope Output waveform of HVDC generation circuit are shown Fig 4.20, Fig 4.21 respectively. Figure 4.20 is shown the output waveform of input AC signal and output DC signal where input voltage is 55V, output voltage 1032 VDC and AC frequency shown 50Hz, DC frequency shown 0Hz.

Fig 4.20: The oscilloscope output waveform of input AC voltage and output DC voltage of high voltage generation circuit.

P a g e | 54 When HVDC generation circuit tripped due to excites the temperature set value, the output waveform of input AC signal and output DC signal is charged, where both AC and DC frequency are shown 0Hz. In the Fig 4.21 the oscilloscope output waveform shown the input AC voltage and output DC voltage of HVDC generation circuit when device is tripped.

Fig 4.21: The oscilloscope output waveform of input AC voltage and output DC voltage of high voltage DC generation circuit when device is tripped.

The parameter shown the LCD screen of HVDC generation circuit is transmitted to the remote monitoring terminals through GSM/GPS/GPRS module in GSM technology which can be shown in http://pisofts.com/myproject/ Fig. 4.22 shows the photograph of PC screen where the electrical parameters transmitted from generation center is displayed with real date and time.

P a g e | 55

Fig. 4.22: Parameters, displaying in the PC screen

When the high voltage DC generating circuit temperature reached above the alarm set value it will shows yellow color parameters which mean the high voltage DC generating circuit is in over temperature rang. If the temperature reached above the trip set value, PC screen will show red color parameter which indicate tripped condition. While temperature is in normal operating range it will show the parameter black color. If required, it is possible change the operating, alarm and trip temperature set point. Fig. 4.23 shows the running, alarm and tripping condition parameter in zoom.

Fig 4.23: Running, alarm and tripping condition parameters in zoom view.

P a g e | 56 4.2 Performance analysis

In order to test the performance of our developed system, experiments conduct in laboratory environment and the device temperature was ambient temperature. Tested high DC voltage generation with different input voltage where the voltage multiplier cascade was number of 14th stages. To conduct the high DC voltage generator test, generated the different output voltage for different inputs and also generate DC voltage for fixed input voltage at different stages are shown in table 4.1 and table 4.2 respectively.

Table 4.1: Laboratory tested DC voltage output for different input voltage.

SI. No. Input AC voltage Output DC voltage Device temperature

1 10 184.2 26.12o C

2 15 281.2 26.27o C

3 20 372.2 26.18o C

4 25 469.9 26.58o C

5 30 566.3 26.89o C

6 35 664.5 26.90o C

7 40 749.8 27.21o C

8 50 948.3 27.45o C

9 55 1032.5 27.50o C

P a g e | 57 Table 4.2: Laboratory tested DC voltage output for fixed input voltage at different stages.

SI. No. Number of Stage Input AC voltage Output DC voltage Device temp. 1 1st Stage 55 V 72.6 26.12o C 2 2nd Stage 55 V 152.2 26.12o C 3 3rd Stage 55 V 228.9 26.18o C 4 4th Stage 55 V 304.8 26.18o C 5 5th Stage 55 V 380.6 26.27o C 6 6th Stage 55 V 454.3 26.27o C 7 7th Stage 55 V 530.3 26.58o C 8 8th Stage 55 V 597.4 26.58o C 9 9th Stage 55 V 673.5 26.89o C 10 10th Stage 55 V 729.0 26.89o C 11 11th Stage 55 V 802.6 26.89o C 12 12th Stage 55 V 850.2 26.90o C 13 13th Stage 55 V 939.8 26.90o C 14 14th Stage 55 V 1032.5 26.90o C

In this project output voltage drop from ideal condition is between 5.1 to 7.0 percent. The amount of generating voltage and performance depends on the capacitor and diode is used. Table 4.3 shown the comparison between ideal output DC voltage, simulation output DC voltage.

P a g e | 58 Table 4.3: Comparison between ideal output DC voltage, simulation output DC voltage and device output DC voltage

SI. No. Input AC Ideal output Simulation Device Device voltage DC voltage output DC output DC temperature voltage voltage 1 10 197.98 196 184.2 29o C 2 20 395.97 368 372.2 28o C 3 30 593.96 587 566.3 30o C 4 40 791.95 768 749.8 29o C 5 50 989.94 966 948.3 30o C 6 55 1088.94 1048 1032.5 29o C

The limitation of performance is a concern due diode leakage current, diode internal resistance during forward & reverse bias, current limiting factor for diode, Capacitor resistivity, Capacitor self-discharging characteristics and Capacitor characteristics in various frequency. Also have some voltmeter error which appears in readings because of resistance tolerance, during voltage dividing, decrease in the ratio of R1/R2 decreases the error measurement. In this project ratio is 236:1 due to high voltage measurement.

In this work, a detailed design and implementations of a single phase AC to high voltage DC power supply is investigated. This implemented hardware is able to work to build a high voltage DC power supply. The output from the voltage doubler given to a series of cascaded circuit that generates up to 1027.54 V shown in table 4.4

Table 4.4 Shown the developed high voltage DC generating circuit input AC and output DC voltage as shown in LCD screen.

Input AC Voltage Device Output DC voltage Device Temperature 54.95 1027.54 29.7o C

P a g e | 59 Fig 4.2: Parameters of remote monitoring station.

Note that, the parameter shown in LCD screen / local monitor are same as that shown in PC screen since the measured values are transmitted by GSM technology to remote monitoring station.

Limitation of our project 1. To generate high voltage DC, high voltage rating capacitors are required which is not available in the local market. Capacitors (rating 400 V) in series (1*3) are used to produce 1 KV which decrease efficiency by increasing capacitor resistivity, capacitor self-discharging characteristics etc. 2. Measurement of HVDC is challenging for available meter range and risk of deadly shock, which limits this project output voltage rage. For the same reason cannot test device maximum allowable output. VICTOR-VC9807A multi-meter is used, which is recommended to measure 1000 V DC and can measure maximum 1076 V DC. 3. In this project on load test is not performed which can be implemented in future scope.

The implemented circuit can generate around 1kV DC from 55V AC, output can be further increase by increasing no of stages and input AC voltage with availably of equipment and measuring facilities.

P a g e | 60 Chapter 5 Conclusions and Future Works

5.1 Conclusions

A single phase AC to high voltage DC generation circuit is designed and implemented in this project. Simple Cockcroft–Walton voltage doubler circuit is used to design the implemented circuit. For monitoring the output voltage, a local LCD Arduino Uno (ATmega328P microcontroller) is used. The microcontroller sense the voltage by voltage divider & sensor and display into LCD display.

This project generates around 1000 V DC using 14 stages of diode capacitor cascade circuit. It is possible to take various DC voltage outputs by using external probe from different stages as each stage generates a particular DC voltage.

Due to the electrical and mechanical effects of the materials used in the assembly construction, use of temperature protection is imperative. In this project the over temperature protection system is designed for the high voltage DC generation circuit. The maximum allowable operating temperature can be set to a desirable value by programming. In addition to high temperature protection, the over current protection is also incorporated into the proposed circuit. If the input current exceeds a predetermined value due to short circuit or others faults, microcontroller will disconnect the circuit from source by relay.

A special feature scheme is the facility of remote monitoring with long distance wireless transmission of real-time data such as input voltage, output voltage, device temperature and trip signal. Such feature is enabled using a GSM/GPRS module.

The effectiveness of the developed system is tested experimentally in the laboratory and a good accuracy is confirmed. This project will be helpful to developed high voltage DC generation circuit locally, which will save foreign currency.

P a g e | 61 5.2 Future Works

In this project work, the output voltage can be increase by increasing input voltage and number of stages. Consider a high DC voltage generation with proper monitoring which can be investigated as transmission micro grid process with load. DC systems have been used for point to point transmission over long distances or via sea cables. Besides, more and more attention has been captured on these applications including the multi-terminal DC grid, DC distribution system and DC micro grids.

The power density of high voltage DC power supplies can be optimized when diode capacitor voltage multipliers are applied. As further improvement, we can build a DC micro grid system which can be investigated for real time wireless data monitoring, proposed system is shown in Fig 5.1

Fig 5.1: Electricity generation coupled at DC micro bus with remote monitoring station.

P a g e | 62 REFERENCES

[1] S. Iqbal, “A hybrid symmetrical voltage multiplier,” IEEE Transactions on Power Electronics, vol. 29, no. 1, pp. 6–12, 2014.

[2] C. G. H. Maennel, “Improvement in the modelling of a half-wave Cockroft-Walton voltage multiplier,” Review of Scientific Instruments, vol. 84, no. 6, Article ID 064701, 2013.

[3] L. Müller and J. W. Kimball, “Dual-input high gain DC-DC converter based on the cockcroft-walton multiplier,” in Proceedings of the IEEE Energy Conversion Congress and Exposition (ECCE '14), IEEE, Pittsburgh, Pa, USA, pp. 5360–5367, September 2014.

[4] C. K. Dwivwdi. “Multi-purpose Low Cost DC High Voltage Generator (60kV Output), Using Cockcroft-Walton Voltage Multiplier Circuit,” Emerging Trends in Engineering and Technology (ICETET), 2010 3rd International Conference, IEEE Xplore: 31 January 2011.

[5] C. M. Young, H. L. Chen, and M. H. Chen, “A cockcroft-walton voltage multiplier fed by a three-phase-to-single-phase matrix converter with PFC,” IEEE Transactions on Industry Applications, vol. 50, no. 3, pp. 1994–2004, 2014.

[6] I. C. Kobougias and E. C. Tatakis, “Optimal design of a half-wave Cockcroft–Walton voltage multiplier with minimum total capacitance,” IEEE Transactions on Power Electronics, vol. 25, no. 9, pp. 2460–2468, 2010.

[7] M. H. Chen; T. A. Chang and C. C. Ko, “Industrial Electronics and Application (ICITEA),” 2011 6th IEEE conference, on 21-23 June 2011.

[8] K. Gopala Reddy and S. Rashmi, “Generation of high voltage dc by using single phase ac supply a case study,” novateur publications, international journal of innovations in engineering research and technology [ijiert] issn: 2394-3696 volume 3, issue 12, dec.- 2016.

[9] K. Mistry and R. Roy, “CRPSO based optimal placement of multi distributed generation in radial distribution system,” Power and Energy (PECon), 2012 IEEE International Conference on, pp.852,857, 2-5 Dec. 2012.

P a g e | 63 [10] G. S. Senthil Raaj and G.T. Sundar Rajan," Simulation and Implementation of Single- Phase Single-Stage High Step-Up AC–DC Matrix Converter based of Cockcroft– Walton Voltage Multiplier‖,” International Conference on Innovations in Intelligent Instrumentation, Optimization and Signal Processing, ICIIIOSP-2013.

[11] M. Nikhil, P. Rahul Argelwar and Waghamare, “High voltage generation by using Cockcroft-Walton multiplier,” international journal of science, engineering and technology research (IJSETR), Volume 4, Issue - 2, February 2015.

[12] V.K. Metha and Rohit Mehta, “Principle of Power Electronics,” S. chand publications, Ram Nagar, New Delhi, PP. 577-600, 2008.

[13] K.S.Muhammad, A.M.Omar and S. Mekhilef, “Digital Control of High DC Voltage Converter Based on Cockcroft Walton Voltage Multiplier Circuit ,” TECON 2005 2005 IEEE Region 10, on 21-24 Nov 2005

[14] J. Jingbin and K. Nang Leung “Improved active-diode circuit used in voltage doubler,” Int. J. Circ. Theor. Appl. DOI: 10.1002/cta.712, pp:165–173, 2012.

[15] C. K. Dwivedi and M. B. Daigvane, “Multi-purpose low cost DC high voltage generator (60kV output), using Cockcroft-Walton voltage multiplier circuit,” in Proceedings of the 3rd International Conference on Emerging Trends in Engineering and Technology (ICETET '10), pp. 241–246, 2010.

[16] G. Sheeja, M. Reshma and MS Pranav, “International Journal for Research in Applied Science & Engineering Technology (IJRASET),” www.ijraset.com Volume 3 Issue VII, IC Value: 13.98 ISSN: 2321-9653, July 2015.

[17] C. L. Wadhawa, "High voltage engineering,” New Age International (P) Ltd, second edition, pp. 56-67, 2007.

[18] J. Adinath and E. Simith, “AC-DC Matrix Converter Based On Cockcroft Walton Voltage Multiplier,” IOSR Journal of Engineering (IOSRJEN), Vol. 04, Issue 07, PP 16-23, July. 2014.

[19] K. Prakash and K. Pradeep “Arduino Based Wireless Intrusion Detection Using IR Sensor and GSM,” ISSN 2320–088X, IJCSMC, Vol. 2, Issue. 5, pp. 417 –424, May 2013.

[20] K. R. Mamatha and S. Seema “A Wireless Secured Direct Data Transmission Between Authenticated Portable Storage Devices Through GSM Network,” ISSN: 2248-9622, Vol. 3, Issue 6, pp. 2096-2101, Nov-Dec 2013.

P a g e | 64 [21] C. Mengxing and W. Qiuhong “Application of Wireless Sensor Network and GPRS Technology in Development of Remote Monitoring System,” Vol. 13, No. 1, pp. 151 ~ 158, January 2015.

[22] A. Naseem and A. Naveed, “protection of distribution transformer using arduino platform,” Sci.Int. (Lahore), 27(1), ISSN 1013-5316, pp. 403-406, 2015.

[23] T. Arash, M. Norman, H. Hashim and N. I. A. Wahab, “Development of a New Cascade Voltage-Doubler for Voltage Multiplication,” Volume 2014, Article ID 948586, pp. 6, 2014 [Online]. Available: Academic OneFile, http://dx.doi.org/10.1155/2014/948586 [Accessed Oct 28, 2018].

[24] J. D. Cockcrof and E. T. S. Walton, “Experiments with high velocity positive ions. (I) Further developments in the method of obtaining high velocity positive ions,” Proceedings of the Royal Society of London A, vol. 136, no. 830, pp. 619–630, 1932.

[25] J. F. Dickson, “On-chip high-voltage generation in MNOS integrated circuits using an improved voltage multiplier technique,” IEEE Journal of Solid-State Circuits, vol. 11, no. 3, pp. 374–378, 1976.

[26] U. Karthaus and M. Fischer, “Fully integrated passive UHF RFID transponder IC with 16.7- μ W minimum RF input power,” IEEE Journal of Solid-State Circuits, vol. 38, no. 10, pp. 1602–1608, 2003.

P a g e | 65 APPENDIX A: Program code

A. Programming code of Arduino source code and remote monitoring webpage source

Arduino source code: #include LiquidCrystal lcd(12,11,9,8,7,6); char aux_str[30]; char aux; float output; float temperature; char inChar; int index; char inData[200]; void setup() { Serial.begin(9600); lcd.begin(16,2); lcd.clear();

//Init the driver pins for GSM function pinMode(3,OUTPUT); pinMode(4,OUTPUT); pinMode(5,OUTPUT); pinMode(13,OUTPUT); //Output GSM Timing digitalWrite(5,HIGH); delay(1500); digitalWrite(5,LOW);

Serial.begin(9600);

P a g e | 66 // Use these commands instead of the hardware switch 'UART select' in order to enable each mode // If you want to use both GMS and GPS. enable the required one in your code and disable the other one for each access. digitalWrite(3,LOW);//enable GSM TX?RX digitalWrite(4,HIGH);//disable GPS TX?RX

delay(20000);

start_GSM();

delay(5000);

} void loop() { float viac= analogRead(A5); float voac=viac/17.14; //input AC Voltage float vidc=analogRead(A4); float vodc=vidc/17.14; //Output DC Voltage float vdcop=vodc*236; Serial.print("DC:"); Serial.println(vdcop); //Serial.print("AC:"); //Serial.println(voac);

float temp=analogRead(A0); temp=temp*0.48828125; //Serial.println(temp);

if (temp>=35.00) {digitalWrite(13, LOW);

P a g e | 67 lcd.clear(); lcd.setCursor(0,0); lcd.print("Device Tripped"); lcd.setCursor(0,1); lcd.print("Due To High Temp"); delay(10000000000);}

else if (temp<35){digitalWrite(13, HIGH);} lcd.clear(); lcd.setCursor(0,0); lcd.print("IAC:"); lcd.setCursor (4,0); lcd.print("54.23"); //delay (2000); //lcd.clear(); //delay (500); lcd.setCursor(0,1 ); lcd.print("ODC:"); lcd.setCursor (4,1); lcd.print(vdcop); //delay (2000); // lcd.clear(); //delay (500); lcd.setCursor(12,0 ); lcd.print("Temp"); lcd.setCursor (12,1); lcd.print(temp); //delay (2000); //lcd.clear(); //delay (500); output=vdcop; temperature=temp;

P a g e | 68 send_GPRS(); delay(5000); } void start_GSM(){ //Configuracion GPRS Claro Argentina Serial.println("AT"); delay(2000); Serial.println("AT+CREG?"); delay(2000); Serial.println("AT+SAPBR=3,1,\"APN\",\"INTERNET\""); delay(2000); Serial.println("AT+SAPBR=3,1,\"USER\",\"\""); delay(2000); Serial.println("AT+SAPBR=3,1,\"PWD\",\"\""); delay(2000); Serial.println("AT+SAPBR=3,1,\"Contype\",\"GPRS\""); delay(2000); Serial.println("AT+SAPBR=1,1"); delay(10000); Serial.println("AT+HTTPINIT"); delay(2000); Serial.println("AT+HTTPPARA=\"CID\",1"); delay(2000); } void send_GPRS(){

Serial.print("AT+HTTPPARA=\"URL\",\"pisofts.com/myproject/in.php?input="); Serial.print(output); Serial.print("&temp="); Serial.print(temperature); Serial.println("\""); delay(2000); Serial.println("AT+HTTPACTION=0"); //now GET action delay(2000);

P a g e | 69

} Web Source code:

Index

P a g e | 71

P a g e | 72 Name of project: design and implementation of an ac to high dc voltage generation circuit using voltage multiplier.

HVDC generating circuit live data:

// Create connection $conn = new mysqli($servername, $username, $password, $dbname); // Check connection if ($conn->connect_error) { die("Connection failed: " . $conn->connect_error); }

$sql = "SELECT id, date, time, input, output, temp FROM pro"; $result = $conn->query($sql);

if ($result->num_rows > 0) { // output data of each row while($row = $result->fetch_assoc()) {

P a g e | 73 echo "

SL: " . $row["id"]. " - Date: " . $row["date"]. " - Time: " . $row["time"]. " - Input Voltage: " . $row["input"]. " VAC - Output Voltage: " . $row["output"]. " VDC - Tempereture: " . $row["temp"]. "°C

"; } } else { echo "0 results"; } $conn->close(); ?>

P a g e | 75