A Multimodal Modulation Scheme for Electric Vehicles’ Wireless Power Transfer Systems, Based on Secondary Impedance

Abstract

This study aimed to investigate a multimodal modulation scheme that takes into account the wide range of output characteristics, numerous constraints, and complex working conditions in the wireless charging of electric vehicles. Key electrical parameters and variables in the secondary stages of electric vehicle wireless power transfer (EV-WPT) systems were evaluated based on capacitive, inductive, and resistive impedance working modes. The limiting duty cycle values, D, of the rectifier were derived by detecting the mutual inductance, M. This multimodal modulation was adopted, based on the secondary equivalent impedance phase, to control the impedance working condition and, hence, achieve optimal working performance. The proposed method can modulate the system performance before and during wireless transmission. The proposed control scheme was verified using a 10 kW EV-WPT experimental prototype under a capacitive impedance working mode with 8.5 kW power output. Our proposed method achieved full power output by modulating the impedance working conditions.