Wireless Charging of Electrical Vehicles

WIRELESS CHARGING OF ELECTRICAL VEHICLES

V.Arun1, Aditi Tiwari2, Ritesh Kumar Singh3, 1Assistant Professor, 2,3Student, 1,2,3Department of Computer Science and Engineering, SRM Institute of Science and Technology, Chennai, Tamil Nadu, India

Abstract- The profitable development and quick adoption of electrified transportation need quick, economical, and reliable charging infrastructure. This paper provides a comprehensive, progressive review of all the wireless charging technologies for an electrical vehicle (EVs), characteristics and standards on the market within the open literature, besides as property implications and potential safety measures. A comparative summary of semiconductive charging and wireless charging is followed by an in-depth description of static wireless charging, dynamic wireless charging (DWC). The credits and downsides of the wireless power transfer technologies, compensation, and power natural philosophy demand for an electric vehicle are mentioned and compared intimately. Finally, a projected circuit topology for resonant inductive wireless charging is given.

Keywords- Wireless Power Transfer technology (WPT), Electrical Vehicle (EV), Power Supply (PS), Coupled Resonance (CMR), Hybrid Electrical Vehicle (HEV), Antenna Device (Tx), Inductive Power Transfer(IPT).

I. INTRODUCTION Electrification in transportation technology has been stressed powerfully for the last many decades and can be growing because the factors are driving the amendment in power sources, like harder regulation triggered by the environmental considerations and urge to cut back the petroleum dependence stricken by the energy security considerations. In automotive applications, the inner combustion engine (ICE), hybrids, CNG and electric cell powered vehicles can however be core power sources in current and future ground vehicle technology which needs more fast steps of potency improvement for fuel potency till 2020 [1]. Despite the present slow pace of penetration, electrical vehicle (EV) is one in every of sturdy candidates within the trade and analysis sectors. Whereas the fast progress is presently being created within the international electrical vehicle market, substantial barriers to massive electron volt adoption still ex- ist. This will be summarized as batteries, charging infrastructure, power interface and client acceptance [2]. With the widespread lithium-ion battery technology, the ability density and specific power capability are mature considerably, however, batteries cannot vie with the tremen- dous energy density of crude oil fuels [3]. Carrying the energy storage system (ESS) at intervals an electrical vehicle throughout the com- plete operation distance has been a significant roadblock to EVs, primarily thanks to the significant and hulking battery system with the present technology. The overhead wire system for the ordinary public tram is often a remedy, however, it additional- ly provided restricted operations at intervals urban application of public transportation, with the sacrifice of town landscape. instead of carrying the ability supply like a battery for the EVs throughout entire travel distance, delivering the ability wirelessly to operational vehicles are often a competitive style answer for future electrified road and vehicle, which might be thought of as a style answer to electron volt introduction [4]. Thus, wireless charging of EVs, either stationary or dynamic on-road charging is often a technology innovation to realize the massive electron volt introduction. However, this technology ought to meet the subsequent requirements; transfer power capability and potency, applicable level of convenience, safety, and business aggressiveness. In earlier Nineties, N. Tesla with bold- ness projected his plan to transmit the power wirelessly through air medium, as tried in Wardenclyffe Tower experiment [5], [6]. With the raised power and energy economical client natural philosophy and small-capacity mobile instrumentality use, the Wireless Power Trans- fer technology (WPT) has drawn vital attraction in technology cluster and connected industries, and therefore the market forecast pre- dicts concerning $2 billion in wireless-power connected. Revenues by 2020 within the space of client natural philosophy, automotive/transportation, industrial automation and significant instrumentality, energy, sensors and transducers, medical and healthcare, and alternative applications [7]. In the WPT field, three main types of WPT have been commercially viable at this time: A) electromagnetic inductive coupling, B) resonant magnetic coupling, and C) microwave-based wireless power transfer. Power beaming by laser concept by NASA or space-based solar power is noticeable in WPT field, but both are either at the conceptual level or little early for commercial application yet [7-9] Even though electron volt looks the attainable answer for transportation trade within the future, there are still many limitations to the technology. One in each of the critical issues for electron volt is that the travel distance per charge. In [10], for the electron volt automobile with the battery energy capability of sixteen kWh, the travel distance is roughly 154 kilometer. Therefore, HEV is presently the high- er answer for additional travel distance till advance battery technologies and charging answer are introduced. Many challenges regarding electron volt stop it from being fully accepted by the mass market as the value of Associate in Nursing electron volt battery, the numbers of electron volt fueling station and therefore the public acceptance for electron volt automobile. According to the survey conducted by Ra- chel et al, as low as 2.7 for every 10 respondents in the US are likely to purchase EVs [11]. In this survey, the most issue influencing the individuals to buy battery electron volts (BEV) is that the familiarity of the respondents with the plug-in EV. On the opposite hands, the respondent’s misperception concerning the high maintenance price and insignificant fuel saving become significant considerations for respondents to not purchase BEVs [12]. This paper starts with the fundamental WPT theory, then provides a quick summary of the most components during a WPT system and classification of WPT. By introducing the newest achievements within the WPT space, we tend to hope the WPT in electron volt applications might gain a widespread acceptance in each theoretical and sensible terms. Also, we tend to hope additional researchers might have associate in Nursing interest and build splendid contributions within the developing of WPT technology.

JETIR1810482 Journal of Emerging Technologies and Innovative Research (JETIR) www.jetir.org 573

II. INDUCTIVE CHARGING OR WIRELESS CHARGING The growing EV market stimulates the demand for a lot of convenient and reliable means that can recharge the battery. WPT technique needs no physical contact between vehicle and charging device, so this overcomes the inconvenience and hazards caused by traditional conductive methods. The initial objective is to replace the conductive charging method by the novel WPT technology while keeping a comparable power level and its efficiency. The long-run goal is to dynamically power the moving vehicles on road. In inductive charging or wireless charging, there's no physical affiliation between the PS (power supply) and EV (electrical vehicle). Fig.1 Illustrate the circuit diagram for inductive charging. Currently, inductive charging is termed as wireless charging and transfers power at a distance of inches. Researcher’s area unit operating to extend this distance up to meters of an air gap. With little physics, power will merely be transferred up to meters; however, with a rise in power level, distant charging proves as a challenge. WPT system is as- sessed by strategies like IPT, coupled resonance (CMR), the static magnet coupled transfer (PMC), an optical device and microwave or electromagnetic wave. CMR is incredibly useful for low- or medium-power WPT; IPT is healthier for high-voltage power transfer since there's no electric circuit concerned. The advantage of IPT is that there's no metal contact between male and femi- nine elements, thence avoiding sparking, with transfer potency at 85%–97%. With the increase in an air gap, the facility transfer potency decreases. For high-energy WPT, it's necessary to stay distance between the secondary pad within the vehicle and also the primary pad on the bottom for ground clearance and to forestall heating.

Fig. 1.Circuit diagram of a wireless charging system.

III. CLASSIFICATION OF WIRELESS POWER TRANSFER TECHNOLOGIES For a stronger understanding of the facility level, potency and application constraints of existing technologies, a classification ought to be administrated per the physical mechanisms. The magnetism (EM) fields made by an antenna device (Tx) by a moving charge area unit divided into 2 regions: 1) Non-radiative region or close-field and 2) Radiative or far-field region. A. Wireless Charging Using Near-Field Technology Near field means that the energy remains among a tiny low region of the Tx. The Tx doesn't emit power if there's no receiver range. The range of those fields is minimal and depends on the dimensions and form of the Tx and receiver. Within the near-field region, the electric and magnetic fields are separate, therefore power is often transferred through the electrical field via electrodes and therefore the field of force via coils. Electric field WPT will transmit power to a very less distance because of a very high decay rate however, magnetic field WPT can transmit power at a distance more than electric because of the ability that magnetic field can penetrate the wall, furniture, and peo- ple. 1) Inductive Power Transfer-Based Wireless Charging: IPT-based wireless charging uses the principle of magnetic induction to transmit power without a medium. Fig. 2 shows the circuit diagram for IPT. It supports Lenz’s law and Faraday’s law where a time-variant current in a conductor creates the magnetic field around the conductor, and a secondary loop (receiver) gets voltage generated due to time-variant magnetic flux. The receiver is connected to the load that closes the circuit to transfer the power without wires. WPT used for communication needs less power, therefore electronic objects, like RFID system, will work expeditiously. However, for applications like running appli- ances, a high power level could also be needed. The IPT system gets upgraded with mere resonance and termed as CMR, i.e., coupling at resonance.

Fig. 2.Block diagram of an Inductive Power Transfer.

2) Coupled Magnetic Resonance-Based Wireless Charging: Magnetic resonance consists of transmitting and receiving coils and capaci- tances for the purpose of compensation and PFC, finally creating a resonant condition for MPT. Global motor companies, such as Tesla, Toyota, Nissan, and so forth, are employing magnetic resonance coupling for WPT.

JETIR1810482 Journal of Emerging Technologies and Innovative Research (JETIR) www.jetir.org 574

Fig.3.Magnetic resonance coupling-based wireless energy transfer system for EV charging. (a) Experimental setup. (b) Electromagnetic sim- ulation model.

3) Permanent Magnet Coupling-Based Wireless Charging: The University of British Columbia has developed a method which relies on the “magnetic gear effect,” where a permanent magnet (Neodymium permanent magnets) acts as a magnetic coupler. The primary-side of permanent magnet rotor rotates the secondary rotor with the equal velocity, called as synchronous speed. There are many drawbacks of this system due to vibrations and noise of many mechanical parts. Another major problem with this scheme is alignment and maintenance issues. For EV charging application, this method is not suitable due to the large system, low efficiency, mechanical rotation, etc.

B. Wireless Charging Using Far-Field Wireless Technologies The far-field technology involves three significant steps to process:

1) conversion of electrical energy to microwave or laser, radio frequency 2) transmitting of converted energy to other through space, and 3) Collection of power at the final state and converting into electrical energy. Mainly there are two types of far-field power transfer technologies 1) Microwave or Radio wave and 2) Laser.

1) Wireless Charging Using Microwave and Radio Wave: WPT using far-field technology is the oldest method because, initially, it was developed for wireless communication. In 1904, Nikola Tesla was the first to transfer power using radio waves at 150 kHz. Due to the directional behaviour of the microwave, it can be used for long distance power beaming.

2) Wireless charging Using laser: Laser technology can transmit power to a considerable distance, but with limited efficiency. EV charging is not very feasible using a laser. Since the mechanism of transfer of power using the laser is also a complex phenomenon, where power can be transferred by converting electrical current into a laser beam, the beam is focused on the photovoltaic cell.

IV. WIRELESS CHARGING TECHNOLOGIES SWC charges the vehicle when the vehicle is stationary. DWC, also known as dynamic en route charging, charges the vehicle when it is in motion. As an example of this is, the project Victoria, led by Endesa in collaboration CIRCE and others, has developed a wireless en route charging for electric buses in Malaga, Spain. QWC also termed as static en route charging in is primarily beneficial for those vehicles which stop at regular intervals of time such as traffic light, bus stops, or taxi stands. For example, in the case of buses stopping at a bus stop, it starts charging wirelessly via underground fit technology. Mostly WPT method used to charge EV wirelessly is through EM fields. The modes SWC, QWC, and DWC of wireless charging are discussed as follows. A. Static Wireless Charging Lukic and Pantic [13] reviewed the present SWC applications, concluding the beginning of maturity for SWC, as SAE has developed standard SAE 2954 [14] for industry-wide specification pointers. The efficiency of power transfer is more effective on SWC since alignment is enhanced. Fig. 6 shows a diagram of the inductive resonant SCW system. A wireless charging system consists of various stag- es, and every stage has its efficiency and complexity. If PS is ac, that is to be converted to dc, using AFE with PFC correction. IPT needs high-frequency ac to transfer power expeditiously. Thus the dc–ac converter converts dc with compensation network to high-frequency ac. An isolated high-frequency transformer is inserted between the converter and the primary coil to safeguard primary winding isolation failure. This high-frequency ac generates an alternating magnetic field following Ampere’s law. This magnetic field links to the secondary winding to produce high-frequency ac within the secondary winding following Faraday’s law. To improve efficiency, the secondary compensation network is used to match the resonant condition. Finally, ac power is rectified by employing a highly efficient rectifier to charge the battery.

Fig. 4.Block diagram of a wireless charging system.

JETIR1810482 Journal of Emerging Technologies and Innovative Research (JETIR) www.jetir.org 575

B. Dynamic Wireless Charging DWC charges the electrical vehicle in moving condition. There's no need to stop and look ahead for charging. This idea was given by Bolger et al. [15] in 1978, within which the energy is transferred to the vehicle while driving. Development of DWC is conducted by a team of researcher at KAIST since 2009. Several major issues are resolved by this project like continuous power transfer, high-frequency current con- trolled electrical converter and different emf characteristics. DWC overcomes most of the issues of the electric vehicle, like anxiety range, battery size, and cost of the battery. Existing models of DWC supports inductive WPT methodology. This technology depends on the magnetic coupling existing between the coils put in underneath the paved surface and furnished a high-frequency current generating EM field, and a pickup coil fitted in the EV. Fig. 5 shows the diagram of DWC. The on-road coils represent a track that endlessly transfers power to the pickup coil. The power captured by this coil, when being appropriately conditioned, charges the EV battery. Low-power wireless systems have also been developed to transfer power to a device with an embedded pickup coil and over a surface containing a Tx coil and plenty of resonators, however, these systems aren't appropriate for EVs, since they move along a path.

Fig. 5.Block diagram of DWC.

Fig.6. Move-and-charge EV system

V. OBJECTIVES AND IMPLEMENTATION METHODS The aim of this paper is to develop an EV charging system to charge its battery using Wireless Power Transmission technique.

A. Objectives The objectives are listed: 1) To make primary and secondary coil with suitable items. 2) Designing a WPT circuit and calculating its performance characteristics. 3) Using electronic circuit that converts AC to DC that charges EV battery. 4) Writing a program that calculates the charging percentage of the battery. 5) Achieving appropriate efficiency of transferred power after doing the circuitry with coils.

B. Implementation Methods 1. Methods for implementing objective 1. • Various journals are reviewed for getting the suitable primary and secondary coil material. • Coils designed for getting maximum power transfer. • Performance of the primary and secondary coils are tested for effective electromagnetic induction. 2. Methods for implementing objective 2. • After testing, determine the loss occurred due to wireless power transfer. • The amount of obtained loss due to power to be transferred are analysed. • The power electronic components are designed and are connected to reduce power loss in electromagnetic induction process. 3. Methods for implementing objective 3 This will mainly focus on the listed specification. • In the development of voltage regulator and hardware power rectifier. • In the design of power electronic circuit for better rectification. • Combining the circuit on the Printed Circuit Board. • Selecting the battery to use in the EV. • To charge the EV battery from rectified output. 4. Methods for implementing objective 4. The following steps to be performed during hardware testing. • All the components are assembled on PCB. • For effective induction winding the primary and secondary coil. • Power is supplied and charging level of battery is tested. • The coil misalignment is decreased if present and the power level of charging is increased. 5. Methods for implementing objective 5. JETIR1810482 Journal of Emerging Technologies and Innovative Research (JETIR) www.jetir.org 576

• The system is connected to the battery and its functioning is observed and time for charge is recorded. • The flux interference is monitored according to Indian Standard. • The advantage of this design is validated based on the performance of existing system.

VI. EXPERIMENTAL SETUP In the Fig.7 the Input of 230V, 50Hz is given to a transformer which steps down the voltage to 12v. The AC power from the transformer is given to primary coil which is establihed in the charging station below the road and the AC power is also given to the rectifier to rectify and filter it to pure DC. This pure DC is regulated by the DC regulator. This output of the regulator is given as supply to the embedded circuit. The primary coil flux is radiated out from the primary coil and is induced in secondary coil present in the EV (under the chassis). The lithium-ion battery in the car gets charged. ADC is used to convert the analog signal to the digital signals as input in the circuit. A programming is performed to know the level of charging of the battery. The fig.8 shows a model of EV (electrical vehicle) with battery which acts as a power source in the model. The fig.9 and fig.10 represents the Secondary coil placed on the model of EV. The primary coil is placed below the platform (road). In fig.11 the light of the LED indicates that the primary and the secondary coils are in reasonable field for WPT.

Fig. 7 Block diagram of WPT circuitry.

Fig. 8 Model of EV with battery

Fig. 9 Secondary coil designed for model of Electric Car

Fig. 10 Secondary coil mounted on the model of EV.

JETIR1810482 Journal of Emerging Technologies and Innovative Research (JETIR) www.jetir.org 577

Fig. 11 LED indicates the Wireless power transfer.

A. Primary and Secondary Coil: Several factors are in consideration when designing the number of turns and size of the primary and secondary coil like, flux density, voltage, losses and other variations. If it has a gradual decrease in the number of turns then it will result in the decrease of voltage and flux density. Similarly if the number of turns are increased the flux density increases and in turn the variations and losses are also increased.

In Tesla.

Where, N= number of turns l= length of coil, I= current in Amps And µ = permeability of free space. The flux which radiates within the coils depends on the conductor’s Area and flux density as if area is increased the flux per Webber increases and flux density is reduced.

The flux radiated is given by: Ø = flux = A * B Where, A=area of the coil

So taking all these values in consideration the coils are designed. The materials used of designing the coils is copper. Earlier aluminium are used to design the coils which are very cheap but radiation of flux is very less. Litz wires are used to lower the parasitic resistance and therefore high Q-factor. Litz wire consist of many insulated thin conductor strands wounded in single patterns. These wires are prone to skin effect and other proximity effects. So as to overcome all these factors copper wires or hollow copper tube are used even though it’s expensive. Copper is a good flux radiator so we used copper material in our project for effective wireless power transfer for the model of EV.

VII. CONCLUSION This paper contains the review of current standing of WPT technologies, its development, and applications in the field of transportation. The challenges and opportunities, regarding technologies and the ability for performance, are mentioned. A comparison is formed between conductive charging and inductive wireless charging. A quick discussion on the static and DWC technologies, the efficiency, and their dependence on numerous factors are mentioned.

VIII. REFERENCES [1] Georg Erdmann, Jürgen Kluge, Philipp Radtke, and H. Wallentowitz, "DRIVE-The Future of Automotive Power," McKinsey & Com- pany, Inc, 2006. [2] Electrification Roadmap, Electrification Coalition, 2009. [3] I. S. Suh, “Application of SMFIR Technology to Future Urban Transportation,” In 21st CIRP Design Conference, Daejeon, Korea, 2011. [4] N. P. Suh, D. H. Cho, and C. T. Rim, "Design of On-Line Electric Vehicle," In Plenary Presentation at 20th CIRP Design Conference, Nantes, France, 2010. [5] N. Tesla, “Art of transmitting electrical energy through natural medium,” U.S Patent 1119732, 18 Apr. 1905. [6] N. Tesla, “Apparatus for transmitting electrical energy,” U.S. Patent 1119732, 1 Dec. 1914. [7] Wireless Power: Current Status and Future Directions, Fuji-Keizai USA Inc., Oct. 2010. [8] Wireless Power Transfer Technology Workshop Proceedings, Korea Institute of Electrical Engineers, 2011. [9] Y. Hori and Y. Yokoi, Wireless Power Transfer, and Infrastructure Construction for Electric Vehicles. Japan: Shemusi Press, 2011. [10] Yilmaz, M.; Krein, P.T., "Review of charging power levels and infrastructure for plug-in electric and hybrid vehicles," IEEE Interna- tional Electric Vehicle Conference (IEVC), vol., no., pp.1,8, 4-8 March 2012 [11] Rachel M. Krause, Sanya R. Carley, Bradley W. Lane, John D. Graham, Perception and reality: Public knowledge of plug-in electric vehicles in 21 U.S. cities, Energy Policy, Volume 63, December 2013, Pages 433-440 [12] Bernama. (2012, April 12) Malaysia hopes for 10- 15 percent electric vehicle in market by 2020. [Online]. Available: http://www.kettha.gov.my/en/content/malaysia-hopes-10-15-cent-electric-vehicles-market-2020 [13] ]S. Lukic and Z. Pantic, “Cutting the cord: Static and dynamic inductive wireless charging of electric vehicles,” IEEE Electrific. Mag., vol. 1, no. 1, pp. 57–64, Sep. 2013.

JETIR1810482 Journal of Emerging Technologies and Innovative Research (JETIR) www.jetir.org 578

[14] The Future of Electric Vehicle Charging is Wireless. Accessed: Aug. 18, 2017. [Online]. Available: https://www.qualcomm.com/ solu- tions/automotive/wevc [15] J. G. Bolger, F. A. Kirsten, and L. S. Ng, “Inductive power coupling for an electric highway system,” in Proc. 28th IEEE Veh. Technol. Conf., Mar. 1978, pp. 137–144.

JETIR1810482 Journal of Emerging Technologies and Innovative Research (JETIR) www.jetir.org 579