100 kW Three-Phase Wireless Charger for EV: Experimental Validation Adopting Opposition Method

Abstract

This paper presents the experimental validation, using the opposition method, of a high-power three-phase Wireless-Power-Transfer (WPT) system for automotive applications. The system under test consists of three coils with circular sector shape overlapped to minimize the mutual cross-coupling, a three-phase inverter at primary side and a three-phase rectifier at receiver side. In fact thanks to the delta configuration used to connect the coils of the electromagnetic structure, a three-phase Silicon Carbide (SiC) inverter is driving the transmitter side. The resonance tank capacitors are placed outside of the delta configuration reducing in this way their voltage sizing. This WPT system is used as a 100 kW–85 kHz ultrafast battery charger for light delivery vehicle directly supplied by the power grid of tramways. The adopted test-bench for the WPT charger consists of adding circulating boost converter to the system under test to perform the opposition method technique. The experimental results prove the effectiveness of the proposed structure together with the validation of fully exploited simulation analysis. This is demonstrated by transferring 100 kW with more than 94% DC-to-DC efficiency over 50 mm air gap in aligned conditions. Furthermore, testing of Zero-Current and Zero-Voltage commutations are performed to test the performance of SiC technology employed.

Modelling and Design of a Coils Structure for 100 kW Three-Phase Inductive Power Transfer System

“…In this case, the boost-converter is set to have an output maximum operating voltage equal to the rate of equivalent battery load in Table 1. At the same time, the WPT-inverter is set to maintain full square wave phase voltages, as already described in [23].…”

“…However, this study is carried out using a Series-Series (SS) compensation topology [23]. This is because a SS network could guarantee a complete reversible structure as well as a simpler resonant tank design, although the Parallel-Series (PS) solution would assure a 30% smaller primary capacitor.…”

“…In particular, in the power bench, all the parts of the WPT system and the testing power converter used to perform the opposition-method technique are enlightened. The shown configuration has been used to test the system without the needing of a full power supply and a load capable of managing the rated power of 100 kW [23]. The chiller, shown in Figure 9b, is used as a safety backup cooling system for the power converters.…”

“…Considering threephase structures, it is possible to find in the literature architecture where the coil system is a three-phase coupler pad using single-phase windings [21,22]. An alternative structure is one where the coils of the single phases are overlapped by an angle such that ideally, the phases are decoupled from each other, the three polar pad (TTP), as already proved in [23]. However, a detailed numerical analysis to obtain this angle was not discussed.…”

An Empirical Survey on Wireless Inductive Power Pad and Resonant Magnetic Field Coupling for In-Motion EV Charging System

“…Polarization Interoperability Misalignment Efficiency (approx. %) Booster Module [77] Polarized High Good -DD [78] Polarized Non-interoperable Medium >90 Layered DD [79] Polarized Non-interoperable Medium -Crossed DD [80] Polarized Poor Medium 80 -90 DD Excitation [81] Polarized Low High -DDQ [82] Polarized High High 91 -95 DDC [83] Polarized High High >90 Meander Type [84] Polarized High High 97 QDQ [85] Polarized High High 85 -91 Quadrupole [86] Polarized High High -Bipolar (BP) [87] Bipolar High high 90 -95 Integrated Bipolar [88] Polarized -High -Poly-phase [89] Polarized Medium High 90 -95 Tri-polar [90] Tri polar High High 91 -95 Integrated Tri-polar [91] Polarized High High -Bipolar Double layer [92] Polarized -High 90 -95 Two pairs of auxiliary [93] Polarized Low Medium 75 -85 Three pairs of auxiliary [94] Polarized Medium Medium 80 -85 Repeater array [95] Polarized High High 75 Rectangular central solenoid [96] Polarized Low High -Triple Quadrature [97] Polarized Very High Very High - Figure 8 shows the physical geometries of the inmotion WRIPT system from previous investigations [77] - [97]. The list of geometrical coil structures involved in inmotion EV charging systems is also suitable for static WRIPT charging states.…”