Transportation electrification is one of the main research areas for the past decade. Electric vehicles (EVs) are taking over the market share of conventional internal combustion engine vehicles. The increasing popularity of EVs results in higher number of charging stations, which have significant effects on the electricity grid. Different charging strat2egies, as well as grid integration methods, are being developed to minimize the adverse effects of EV charging and to strengthen the benefits of EV grid integration. In this paper, a comprehensive review of the current situation of the EV market, standards, charging infrastructure, and the impact of EV charging on the grid is presented. The paper introduces the current EV status, and provides a comprehensive review on important international EV charging and grid interconnection standards. Different infrastructure configurations in terms of control and communication architectures for EV charging are studied and evaluated. The electric power market is studied by considering the participation roles of EV aggregators and individual EV owners, and different optimization and game based algorithms for EV grid integration management are reviewed. The paper specially presents an evaluation on how the future EV development, such as connected vehicles, autonomous driving, and shared mobility, would affect EV grid integration as well as the development of the power grid moves toward future energy Internet and how EVs would affect and benefit the development of the future energy Internet. Finally, the challenges and suggestions for the future development of the EV charging and grid integration infrastructure are evaluated and summarized.

Electric vehicles standards, charging infrastructure, and impact on grid integration: A technological review

The momentum toward high efficiency, high frequency, and high power density in power supplies limits wide use of conventional wire-wound magnetic components This paper gives an overview of planar magnetic technologies with respect to the development of modern power electronics The major advantages and disadvantages in the use of planar magnetics for high-frequency power converters are covered, and publications on planar magnetics are reviewed A detailed survey of winding conduction loss, leakage inductance, and winding capacitance for planar magnetics is presented so power electronics engineers and researchers can have a clear understanding of the intrinsic properties of planar magnetics

Overview of Planar Magnetic Technology—Fundamental Properties

Review of static and dynamic wireless electric vehicle charging system

The use of $LLC$ resonant converters has gained popularity in multiple applications that require high conversion efficiency and galvanic isolation. In particular, many applications like portable devices, flat TVs, and electric vehicle battery chargers require demanding slim-profile packaging and enforce the use of planar transformers (PTs) with low-height, low leakage inductance, excellent thermal characteristics, and manufacturing simplicity. The main challenge in successfully designing $LLC$ converters with PT resides in controlling high-parasitic capacitances produced by large overlapping layers in PT windings. When the parasitic capacitances are not controlled, they severely impair the converters’ performance and regulation, and limit the application of PTs in high-frequency $LLC$ converters. This paper characterizes the PT capacitance issue in detail and proposes mitigation strategies to improve the performance of $LLC$ converters with PTs. A systematic analysis is performed, and six PT winding layouts are introduced and benchmarked with a traditional design. As a result of the investigation, an optimized structure is obtained, which minimizes both the interwinding capacitance and ac resistance, while improving the regulation performance of $LLC$ converters. Experimental measurements are presented and show a significant reduction of parasitic capacitance by up to 21.2 intra- and 16.6 interwinding capacitances, without compromising resistance. This substantial capacitance reduction has a tangible effect on the regulation performance of $LLC$ resonant converters. Experimental results of the proposed PT structure in a 1.2 kW $LLC$ resonant converter show a reduction in common-mode noise, extended output voltage regulation, and improved overall efficiency of the converter.

LLC Converters With Planar Transformers: Issues and Mitigation

Many different types of electric vehicle (EV) charging technologies are described in literature and implemented in practical applications. This paper presents an overview of the existing and proposed EV charging technologies in terms of converter topologies, power levels, power flow directions and charging control strategies. An overview of the main charging methods is presented as well, particularly the goal is to highlight an effective and fast charging technique for lithium ions batteries concerning prolonging cell cycle life and retaining high charging efficiency. Once presented the main important aspects of charging technologies and strategies, in the last part of this paper, through the use of genetic algorithm, the optimal size of the charging systems is estimated and, on the base of a sensitive analysis, the possible future trends in this field are finally valued.

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Electric Vehicles Charging Technology Review and Optimal Size Estimation

High frequency planar transformer (HFPT) is an up-and-coming technology which can be used for designing a contact-less battery charging platform In this paper, fractal-based high frequency planar transformers are presented with two different structures: 4-to-1 and 16-to-4 turn ratio Because they are PCB-based transformers, two cases of 08 mm and 16 mm thickness were investigated A finite-element method has been used to calculate the magnetic field LLC resonant converter has been designed to improve the conversion efficiency The voltage ratio has been measured with and without a capacitor at the primary side The winding with a capacitor can increase the efficiency without any distortion and harmonics

High Frequency Planar Transformer (HFPT) for Universal Contact-Less Battery Charging Platform

The rapid expansion of plug-in electric vehicles (PEVs) has led to the requirement for advanced charging and power delivery techniques. Smart transformers, AC and DC fast charging techniques have the ability to connect a vehicle to the distribution network at very high power levels. If this connection is not properly utilised, a detrimental impact on the distribution network could occur. By utilising the vehicle-to-grid technique alongside smart scheduling for charging, PEVs can support the distribution network. Improving the compatibility between different types of electric vehicles and the distribution grid can be achieved by diversifying charging methods to a multi-platform charging solution. Advanced wireless charging methods can allow PEVs to travel long distances without stopping or requiring a charging station. This chapter will discuss different types of charging technologies and the utilisation of vehicle-to-grid support on a distributed network.

PEV Charging Technologies and V2G on Distributed Systems and Utility Interfaces

High Frequency Wireless Planar Transformers (HFWPT) are an up-and-coming technology which can be used for designing an electric vehicle (EV) on board wireless battery charging platform. In this paper, HFWPTs are used to investigate the flux leakages and other EMC problems which are associated with wireless charging system's efficiency. The HFWPT was designed using the bifilar winding concept on PCB. A LLC resonant converter has been designed to improve the conversion efficiency with a maximized air gap. Assisted by a near-field scanner, the magnetic field has been analyzed with and without a magnetic ferrite core at resonant frequency. The magnetic ferrite core in this arrangement is used to minimize flux leakages and to increase the magnetizing impedance.

Investigation of flux leakages and EMC problems in wireless charging systems for EV and other mobile applications

A High Frequency and High Power Density Wireless Planar Transformer (HFHPD-WPT) is a very attractive future technology which can provide power to an electric vehicle (EV) through a contactless charging system. In this paper, EMC computer modeling and simulation techniques are employed to investigate the magnetic flux distribution and associated EMC problems such as stray fluxes and hot spots. The bifilar planar spiral coils of the transformer are designed on multilayer PCB. A finite element method (FEM) has been used to calculate the magnetic field. The effect of the planar magnetic ferrite cores on magnetic flux distribution has been investigated by using three designs, where the first design has the ferrite core only at the primary side, the second draft has a planar core on the primary and secondary side, and the third design has a U-Shape magnetic core for the primary and secondary side. Both designs are operating at a resonant frequency of 60 kHz. A new proposed design is introduced to minimize flux leakages and reduce hot spots, in order to improve the flux distribution and to increase the magnetizing impedance.

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Chirag Panchal

Papers

Review of static and dynamic wireless electric vehicle charging system

High Frequency Planar Transformer (HFPT) for Universal Contact-Less Battery Charging Platform

PEV Charging Technologies and V2G on Distributed Systems and Utility Interfaces

Investigation of flux leakages and EMC problems in wireless charging systems for EV and other mobile applications

Investigation of magnetic flux distribution of EV wireless charging systems