This paper proposes a four-plate compact capacitive coupler and its circuit model for large air-gap distance capacitive power transfer (CPT). The four plates are arranged vertically, instead of horizontally, to save space in the electric vehicle charging application. The two plates that are on the same side are placed close to each other to maintain a large coupling capacitance, and they are of different sizes to maintain the coupling between the primary and secondary sides. The circuit model of the coupler is presented, considering all six coupling capacitors. The LCL compensation topology is used to resonate with the coupler and provide high voltage on the plates to transfer high power. The circuit model of the coupler is simplified to design the parameters of the compensation circuit. Finite-element analysis is employed to simulate the coupling capacitance and design the dimensions of the coupler. The circuit performance is simulated in LTspice to design the specific parameter values. A prototype of the CPT system was designed and constructed with the proposed vertical plate structure. The prototype achieved an efficiency of 85.87% at 1.88-kW output power with a 150-mm air-gap distance.

A Four-Plate Compact Capacitive Coupler Design and LCL -Compensated Topology for Capacitive Power Transfer in Electric Vehicle Charging Application

Wide bandgap semiconductors, such as gallium nitride (GaN)-based power devices have become increasingly popular in the automotive industry due to their low on-state resistance and fast switching capabilities These devices are sought to replace silicon (Si) devices in power electronics converters for vehicular applications GaN devices dissipate less energy during each switching event, thus, GaN converter designers can significantly increase the switching frequency without increasing switching losses, relative to Si converters However, one item of concern is that the high $dv/dt$ of GaN devices, due to the increased switching speed, has the potential to deteriorate the electromagnetic interference (EMI) emission of power converters, and thus may fail the corresponding regulations for vehicles To understand these effects, this paper presents an experimental case study on the switching characteristics and common mode (CM) noise generation of a GaN-based half-bridge configuration operating in the synchronous boost mode A comprehensive comparison has been made between the chosen GaN high electron mobility transistors (HEMTs) and Si MOSFET in terms of switching voltage waveforms, ground leakage currents, and CM noise spectrum By parametrically increasing the gate resistance of GaN HEMT and Si MOSFET, the tradeoff between converter efficiency and CM noise generation is also quantified

A Case Study on Common Mode Electromagnetic Interference Characteristics of GaN HEMT and Si MOSFET Power Converters for EV/HEVs

This paper presents the design, analytical estimation of power losses, and experimental measurement of choke inductors for switched-mode power inverters. The described approach is applicable to a wide variety of circuits such as Class-E inverters and converters. The expressions required to design the magnetic core in the choke inductor using the area–product ( $A_p$ ) method are given. The equations for the dc resistance, ac resistance at high frequencies, and dc and ac power losses are provided for the solid round winding wire. To validate the presented approach, an example class-E zero-voltage switching power inverter with practical specifications is considered. A core with air gap is selected to avoid core saturation in the choke inductor, which conducts dc current and a small ac current. The gapped core power loss density and power loss are estimated using Steinmetz empirical equation. It is shown that the winding power loss due to the dc current is dominant for the given design. A comparison between the area–product $A_p$ method and the preexisting core geometry coefficient $K_g$ method is presented. The measured magnitude of the inductor impedance has shown that the designed choke is useful up to ten times the switching frequency.

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Analysis and Design of Choke Inductors for Switched-Mode Power Inverters

This letter presents the technique for estimating the self-capacitance of single-layer air-core solenoid inductors with separation between the insulated turns. In single-layer air-core inductors, the self-capacitance is due to the conductor turn-to-turn capacitances. The analytical framework to determine the turn-to-turn capacitances of single-layer air-core inductors with uniformly and nonuniformly separated conductor turns is established. The influence of the wire insulation coating is taken into consideration. A representative design example of a single-layer air-core inductor is presented and its self-capacitance and self-resonant frequency are predicted. The presented analytical approach was tested by experimental measurements on the designed inductor. The derived analytical expressions are useful for designing air-core inductors for high frequency (HF) and very HF applications such as electromagnetic interference/electromagnetic compatibility filters and radio and TV transmitters.

Self-Capacitance of Single-Layer Inductors With Separation Between Conductor Turns

In a small standalone power supply system containing renewable energy, the frequency response is usually supported during frequency excursion by the conventional generators only. This may result in a less effective recovery of the system frequency in a wind energy dominant standalone system. The support from the wind turbine in the frequency regulation will significantly improve the recovery performance. However, the natural inertia of the variable speed wind turbine is very small compared to that of the conventional generators. Therefore, a fast responding energy storage can significantly improve the frequency response capability. In this paper, a control technique has been proposed to utilize the superconducting magnetic energy storage to be integrated with the permanent magnet synchronous generator based wind turbine to improve the power system frequency regulation and the results are found to be promising.

Enhanced Frequency Support From a PMSG-Based Wind Energy Conversion System Integrated With a High Temperature SMES in Standalone Power Supply Systems

This paper presents a derivation of an expression for the self-capacitance of single-layer coupled toroidal inductors, which are commonly used in EMI filters and other applications. A physics-based geometrical method is used in the derivation. This method requires information about the inductor geometry and material properties, such as dimensions of core, technique of winding, as well as diameter, thickness, and permittivity of winding wire isolation. The geometrical method is very useful because it saves time and does not require an impedance analyzer. However, all information about material properties has to be known. The theoretical results are validated by experimental results. The agreement between the calculated and measured results was very good.

Self-Capacitance of Coupled Toroidal Inductors for EMI Filters

Parameters calculation of coupled coils equivalent circuit of EMI filter

The selection of the less expensive power conditioning system (PCS) is the aim of the work where two types of PCS are taken into consideration. The first type of PCS is based on superconducting magnetic energy storage (SMES) while the second one is based on supercapacitor energy storage (ScES). The comparison is based on installed power as the criterion. An illustrative example is given in the work

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Comparison of SMES and ScES based power conditioning systems

Property comparisons of TIGHTpak toroidal and double layer common choke

—The attenuation of common mode chokes based on nanocrystalline VITROPERM 500F and Mn-Zn ferrite materials are analysed. It has been proved that the nanocrystaline choke gives much higher attenuation than ferrite one.

S. Pasko

Papers

Self-Capacitance of Coupled Toroidal Inductors for EMI Filters

Parameters calculation of coupled coils equivalent circuit of EMI filter

Comparison of SMES and ScES based power conditioning systems

Property comparisons of TIGHTpak toroidal and double layer common choke

Attenuation of Nanocrystalline and Ferrite Common Mode Chokes for EMI Filters