Inductive Load Arc Suppression Application Note
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MM2EMD L7.Pdf
University of Nottingham Electromechanical devices MM2EMD Lecture 7 – Transistors - Switching high voltage things on with a low voltage Dr. Roderick MacKenzie [email protected] Summer 2015 @rcimackenzie Released under Outline of the lecture •No recap of last lecture :) •Transistor basics •Relays (Mechanical transistor) •NPN Bipolar Junction Transistors •PNP Bipolar Junction Transistors •MOSFETs •Push pull pairs to drive MOSFETs •One last thing •Summary 2 Roderick MacKenzie MM2EMD Electromechanical devices Outline of the lecture •No recap of last lecture :) •Transistor basics •Relays (Mechanical transistor) •NPN Bipolar Junction Transistors •PNP Bipolar Junction Transistors •MOSFETs •Push pull pairs to drive MOSFETs •One last thing •Summary 3 Roderick MacKenzie MM2EMD Electromechanical devices Roderick MacKenzie Roderick electrical devices suchas motors. high voltage control electronics • This lecture is making low voltageThis lecture Think back to lecture 1. lecture Think backto Dave Jones Smart Electronic Circuits (low voltage) Circuits voltage) (high S.J. de Waard Simple Simple Electrical MM2EMD Electromechanical devices 4 Think about an AND gate chip And gate Biro •Look at the tiny thin pins which are used to carry current in and out of the chip. •These pins can supply 25 mA @ 5V at the most. 5 Roderick MacKenzie MM2EMD Electromechanical devices But why is this? i •If we take the top off the chip h p o with acid. G ● Look how much small the actual chip is and look at the tiny bond wires (25 mA @ 5V max!!!) 6 Roderick MacKenzie MM2EMD Electromechanical devices Roderick MacKenzie Roderick 500 V • It needsIt Now think about this motor. this about Now think to run.to 10 Amps 10 at CMBJ the current. -
Snubber Considerations for IGBT Applications
Snubber Considerations for IGBT Applications by Yi Zhang, Saed Sobhani, Rahul Chokhawala International Rectifier Applications Engineering 233 Kansas St., El Segundo, CA, 90245 USA Abstract - Snubber circuits can be used to protect fast Note that the fault current transients are more switching IGBTs from turn-on and turn-off voltage effectively protected by considerably slowing the rate transients. Snubbers are available in various of fall of fault current. Fault current turn-off protection configurations and a clear understanding of their through electronic gate control is convered in detail operation is necessary to make the appropriate elsewhere[1]. selection. This paper will discuss pros and cons of these circuits. Decoupling capacitors, RCD voltage Decoupling Capacitors clamp circuit, RCD charge-discharge snubbers are As mentioned earlier, the magnitude of transient voltage included in the discussion. depends on the trapped energy in the circuit stray inductance, also call “DC loop” inductance LS. As a Introduction preventive measure, steps should be taken to improve When a power device is abruptly turned off, trapped the circuit layout. Usage of laminated copper plates, energy in the circuit stray inductance is dissipated in minimizing the size of the “DC loop” and choosing the switching device, causing a voltage overshoot source capacitance with inherently low self inductance across the device. The magnitude of this transient are ways to lower stray inductance [2]. Decoupling voltage is proportional to the amount of stray capacitors, connected across the module’s bus inductance and the rate of fall or turn-off current. The terminals, as shown in Fig.1a, are found to be useful situation is at its worst for fast switching IGBT for low/medium current applications. -
AN-MISC-032 Date Issued: 5/24/16 Revision: REV
APPLICATION NOTE This information provided by Automationdirect.com Technical Support Team is provided “as is” without a guarantee of any kind. This document is provided to offer assistance in using our products. We do not guarantee that the contents are suitable for your particular application, nor do we assume any responsibility for applying the contents to your application. Subject: Transient Suppression Guidelines for AutomationDirect PLCs Number: AN-MISC-032 Date Issued: 5/24/16 Revision: REV. A Transient Suppression for Inductive Loads in a Control System This Application Note is intended to give a quick overview of the negative effects of transient voltages on a control system and provide some simple advice on how to effectively minimize them. The need for transient suppression is often not apparent to the newcomers in the automation world. Many mysterious errors that can afflict an installation can be traced back to a lack of transient suppression. What is a Transient Voltage and Why is it Bad? Inductive loads (devices with a coil) generate transient voltages as they transition from being energized to being de-energized. If not suppressed, the transient can be many times greater than the voltage applied to the coil. These transient voltages can damage PLC outputs or other electronic devices connected to the circuit, and cause unreliable operation of other electronics in the general area. Transients must be managed with suppressors for long component life and reliable operation of the control system. This example shows a simple circuit with a small 24V/125mA/3W relay. As you can see, when the switch is opened, thereby de-energizing the coil, the transient voltage generated across the switch contacts peaks at 140V! Example: Circuit with no Suppression Oscilloscope Volts 160 140 120 100 + 80 24 VDC 60 - Relay Coil 40 (24V/125mA/3W, 20 AutomationDirect part no. -
AN1048/D RC Snubber Networks for Thyristor Power Control
AN1048/D RC Snubber Networks For Thyristor Power Control and Littelfuse.com Transient Suppression By George Templeton APPLICATION NOTE Thyristor Applications Engineer INTRODUCTION Edited and Updated RC networks are used to control voltage transients that ǒdVǓ DEVICE PHYSICS could falsely turn-on a thyristor. These networks are called dt s snubbers. Static dV turn-on is a consequence of the Miller effect The simple snubber consists of a series resistor and dt capacitor placed around the thyristor. These components and regeneration (Figure 1). A change in voltage across the along with the load inductance form a series CRL circuit. junction capacitance induces a current through it. This cur- Snubber theory follows from the solution of the circuit’s rent is proportional to the rate of voltage change ǒdVǓ . It differential equation. dt Many RC combinations are capable of providing accept- triggers the device on when it becomes large enough to able performance. However, improperly used snubbers can raise the sum of the NPN and PNP transistor alphas to unity. cause unreliable circuit operation and damage to the semi- conductor device. A Both turn-on and turn-off protection may be necessary A for reliability. Sometimes the thyristor must function with a I IA BP PE range of load values. The type of thyristors used, circuit V PNP configuration, and load characteristics are influential. I CJ I I 1 P J CP NB CJ Snubber design involves compromises. They include N C C I J CN I2 dv I G P cost, voltage rate, peak voltage, and turn-on stress. Practi- J dt B cal solutions depend on device and circuit physics. -
Basic DC Motor Circuits
Basic DC Motor Circuits Living with the Lab Gerald Recktenwald Portland State University [email protected] DC Motor Learning Objectives • Explain the role of a snubber diode • Describe how PWM controls DC motor speed • Implement a transistor circuit and Arduino program for PWM control of the DC motor • Use a potentiometer as input to a program that controls fan speed LWTL: DC Motor 2 What is a snubber diode and why should I care? Simplest DC Motor Circuit Connect the motor to a DC power supply Switch open Switch closed +5V +5V I LWTL: DC Motor 4 Current continues after switch is opened Opening the switch does not immediately stop current in the motor windings. +5V – Inductive behavior of the I motor causes current to + continue to flow when the switch is opened suddenly. Charge builds up on what was the negative terminal of the motor. LWTL: DC Motor 5 Reverse current Charge build-up can cause damage +5V Reverse current surge – through the voltage supply I + Arc across the switch and discharge to ground LWTL: DC Motor 6 Motor Model Simple model of a DC motor: ❖ Windings have inductance and resistance ❖ Inductor stores electrical energy in the windings ❖ We need to provide a way to safely dissipate electrical energy when the switch is opened +5V +5V I LWTL: DC Motor 7 Flyback diode or snubber diode Adding a diode in parallel with the motor provides a path for dissipation of stored energy when the switch is opened +5V – The flyback diode allows charge to dissipate + without arcing across the switch, or without flowing back to ground through the +5V voltage supply. -
Minimizing Switching Ringing at TPS53355 and TPS53353 Family Devices
Application Report SLUA831A–July 2017–Revised November 2018 Minimizing Switching Ringing at TPS53355 and TPS53353 Family Devices Benyam Gebru ABSTRACT The system reliability of a high efficiency DC/DC converter with a fast slew rate is improved when switch node ringing is reduced. This document describes switching ringing reduction methods and lab bench test results with the 30-A TPS53355, and also applies to the pin compatible 20-A TPS53353. Both devices are well-suite for rack server, single board computer, and hardware accelerator applications that benefit from the fast transient response time of D-CAPTM control, or when multi-layer ceramic capacitors are undesirable for the output filter. Contents 1 Introduction ................................................................................................................... 2 2 Proper Measurement Method of Switch Ringing ........................................................................ 2 3 Minimize the Switch Ringing by Adding RC Snubber and Bootstrap Circuit......................................... 5 4 Practical Design.............................................................................................................. 8 5 Adding Bootstrap Resistor ................................................................................................ 11 6 Effects of Snubber on the Efficiency Performance .................................................................... 12 7 Summary ................................................................................................................... -
Single and Dual RC Snubbers
RC Snubbers Single and dual RC snubbers Description: A range of RC snubbers suitable for a broad range of circuit protection applications. The RC snubbers are mounted in a potted box with 6.3mm push on tabs for easy connection to the circuit. The devices have 80mm fixing centers so can be easily mounted alongside industry standard thyristor and diode modules. The range of RC snubbers are suitable for 50Hz/60Hz operation with resistive loads. Images shown are computer generated, for accurate package information please see product drawing Product Highlights Applications 80mm fixing centres Thyristor protection in AC and DC circuits Compact package Diode Protection 440Vrms rating (690Vrms available upon request) Output filters Component Data: Product Reference Maximum varistor energy (J) l voltage 10% 10% - - 10/1000us 2ms Configuration Resistance Value (Ohms) +/ Max. Power Dissipation (W) Capacitance Value (uf) +/ Maximum working voltage (Vrms) Dimension figure. Circuit configuration Varistor nomina (Vrms) ECLRC440 Single RC 56 10 0.22 440 N/A 1 A ECLRC440-2 Dual RC 56 10 0.22 440 N/A 2 B Humidity max. 50% RH @ 35 C / 90% RH @ 20 C Pollution degree: III Isolation: 2500Vrms / 1min Operation temperature: -25C to 80C Mounting position: Any Approx weight: 70grms (single) / 76grms (Dual) (1) The voltages shown are for general phase control applications in W1C circuits. (2) Typical voltage for general purpose rectifier circuits ATTENTION: for continuous operation near to 90 deg phase angle a larger power loss will occur, please consult the factory in these circumstances to see if the device is suitable for the application [email protected] Data can be changed without notice. -
What Are Electronic Timing Relays? a Relay Is an Electromagnetic Switch Which Operates on a Small Electric Current
What Do You Know About Electronic Timing Relays? There are certain components that form the core of the modern control systems. One such important component used in many applications is an Electronic Timing Relay (ETR). Let us start by understanding some basics. What are Electronic Timing Relays? A relay is an electromagnetic switch which operates on a small electric current. These switches are used to turn on or off a circuit of higher amperage. When electricity is applied, the electromagnetic coil causes the armature to move, opening or closing the contacts, controlling the flow of electricity from a high current source connected to the load side of the relay. Relays act as bridges that activate larger currents using smaller ones. This allows you to use a relay to safely switch on and off different devices. An Electronic Timing Relay has circuitry integrated which controls the armature motion upon input voltage being applied. This addition gives the relay the property of time-delay actuation. Electronic Timing Relays are constructed to delay armature motion on coil energization, de-energization, or both. ETRs provide a wide range of selectable functions so that users can customize their specific machine operation. Relay Components and Operation What are the Best Features of Electronic Timing Relays? Electronic timing relays are used in a number of electronic applications, owing to the unending list of their features, which are as follows: • Multi-function timer, which allows the user to adjust between multiple timing functions. • High duty cycle applications. • DIN rail or panel mounting. • Resistant to mechanical shock and vibration. -
Photovoltaic Couplers for MOSFET Drive for Relays
Photocoupler Application Notes Basic Electrical Characteristics and Application Circuit Design of Photovoltaic Couplers for MOSFET Drive for Relays Outline: Photovoltaic-output photocouplers(photovoltaic couplers), which incorporate a photodiode array as an output device, are commonly used in combination with a discrete MOSFET(s) to form a semiconductor relay. This application note discusses the electrical characteristics and application circuits of photovoltaic-output photocouplers. ©2019 1 Rev. 1.0 2019-04-25 Toshiba Electronic Devices & Storage Corporation Photocoupler Application Notes Table of Contents 1. What is a photovoltaic-output photocoupler? ............................................................ 3 1.1 Structure of a photovoltaic-output photocoupler .................................................... 3 1.2 Principle of operation of a photovoltaic-output photocoupler .................................... 3 1.3 Basic usage of photovoltaic-output photocouplers .................................................. 4 1.4 Advantages of PV+MOSFET combinations ............................................................. 5 1.5 Types of photovoltaic-output photocouplers .......................................................... 7 2. Major electrical characteristics and behavior of photovoltaic-output photocouplers ........ 8 2.1 VOC-IF characteristics .......................................................................................... 9 2.2 VOC-Ta characteristic ........................................................................................ -
Lossless Active Snubber for Half-Bridge Output Rectifiers
Europaisches Patentamt 19 European Patent Office Office europeen des brevets © Publication number: 0 614 267 A1 12 EUROPEAN PATENT APPLICATION (2j) Application number : 94301445.6 6i) Int. CI.5 : H02M 7/06 (22) Date of filing : 01.03.94 (§) Priority : 05.03.93 US 27031 @ Inventor : Tsai, Fu Sheng 105 Bartlett Street @ Date of publication of application : Northboro, Massachusetts 01532 (US) 07.09.94 Bulletin 94/36 Inventor : Dhaval, Dalai B. 70-9 Commons Drive Shrewsbury, Massachusetts 01545 (US) @ Designated Contracting States : DE FR GB IT (74) Representative : Goodman, Christopher et al Eric Potter & Clarkson © Applicant : DIGITAL EQUIPMENT St. Mary's Court CORPORATION St. Mary's Gate 146 Main Street Nottingham NG1 1LE (GB) Maynard, Massachusetts 01745 (US) @) Lossless active snubber for half-bridge output rectifiers. (57) A bridge-type primary switching circuit (12) is represented by a pulsed voltage source (VSW). The primary switched waveform is transformed to secondary circuit (14) using a transformer (T1) with the required turns ratio N and a cen- ter-tapped secondary winding (16). Half-bridge rectifier (18) formed by diodes (DR1) and (DR2) rectifies the secondary waveform and feeds the waveform through a low-pass filter (LF) and (CF) to obtain the desired DC output voltage. The snubber circuit (20) is represented by switch-diode-capacitor combinations (SA- DS1-CS1) and (SB-DS2-CS2) across each rec- tifier (DR1) and (DR2). Capacitances (CS1) and (CS2) are selected large enough such that their voltages remain essentially constant during a switching cycle. The controlled switches (SA) and (SB) are turned ON with a specific delay after the primary voltage reaches a magnitude close to the input voltage in order to allow the rectifier diodes (DR1) and (DR2) to be commu- tated. -
FAGOR Avalanche Rectifiers
Application Note Fagor Electrónica Semiconductores Avalanche Rectifiers Avalanche Rectifiers are diodes that can tolerate voltages above the repetitive reverse maximum blocking voltage (Vrrm) and, furthermore, dissipate a specified maximum energy during these pulses. Here we describe how these diodes differ from normal rectifiers and the applications to which they are suited. Introduction Rectifiers are two-terminal devices that are used to conduct current in one direction but block in the other according to a characteristic of the type shown in Figure 1. Standard rectifiers operate stably in either the Reverse Blocking Mode or in the Forward Conducting Mode. In the first case, only a very small leakage current flows so that power dissipation in the device is not important. In the second case, the forward voltage is more than a volt so considerable power may be dissipated in the device, but provided the heat is extracted efficiently the junction temperature will not exceed the maximum rated value and the device will be stable. I Figure 1 Modes of Operation within the I-V characteristic of Rectifiers. V Forward Concucting Avalanche Reverse Blocking Mode Mode Mode Further limitations apply when the rectifier is switched from conducting a large forward current to blocking a large reverse voltage. During a time after switching, the current that flows in the reverse direction greatly exceeds the reverse leakage value. Even if the delay in establishing the blocking condition is not important in the application, the additional power dissipated may cause the device to overheat and eventually fail. The recovery time depends strongly on the forward current before switching but standard conditions have been established to measure the Trr parameter (Typically: I F=0.5A switched to I R=1A at t=0 and recuperation defined has having occurred when I R=0.25A). -
Experiment (1) Principles of Switching
Experiment (1) Principles of Switching Introduction When you use microcontrollers, sometimes you need to control devices that requires more electrical current than a microcontroller can supply; for this, electrical relays and transistors are used. In this experiment, we will investigate two types of switching; electromechanical switching and solid state switching. Objectives This experiment aims to: 1- Understand the basic principles of switching devices. 2- Introduction to electromechanical switching as well as solid state switching. 3- Understand the advantages and disadvantages of each type. 4- Study the relative speed of different type of switches. Theory Electromechanically Relays Relays are electromechanical devices that use an electromagnet to operate a pair of movable contacts from an open position to a closed position. The relay is a switch that is controlled by a small electric current. It can be used to control motors, heaters or lamps circuits which themselves can draw a lot more electrical power. Figure 1 shows the circuit symbol for a relay. Figure 1: Circuit symbol for a relay In figure 2, the relay’s coil is energized by the low-voltage (12 VDC) source, while the single- pole, single-throw (SPST) contact interrupts the high-voltage (480 VAC) circuit. It is quite likely that the current required to energize the relay coil will be hundreds of times less than the current rating of the contact. Typical relay coil currents are well below 1 amp, while typical contact ratings for industrial relays are at least 10 amps. Mechatronics Systems Design Lab Figure 2: Relay drive an AC load One relay coil/armature assembly may be used to actuate more than one set of contacts.