Indirect Load Estimation of Double-Sided LCL Compensated Wireless Power Transfer System for Electric Vehicles Battery Charging

A double-sided inductor-capacitor-inductor compensated wireless charging system with transmitter side power control and indirect load estimation is presented in this paper. This helps in achieving constant current (CC) and constant voltage (CV) charging mode for the electric vehicle battery. There is no link for wireless communication between the transmitter and receiver. The proposed compensation topology achieves CC output on the transmitter side and a unity system power factor. By using the phase relation between compensation capacitor voltage and resonant current on transmitter side, the output load parameters can be controlled. This approach uses Reflected Impedance Theory and Quadrature Transformation Algorithm to calculate both real and reactive power. By using Proportional-Integral Current or Voltage controlled Phase-Shifted H-Bridge Inverter, the CC-CV charging mode of lithium-ion EV battery is accomplished. The MATLAB Simulink results match with the theoretical calculation at 85KHz resonant frequency.