Analysis of Parameter Tolerance and Voltage Balance of Medium-Voltage Transformerless Multilevel Inductive Power Transfer System with Excitation Coils

This study investigates the robustness of parameters and the controllability of a medium-voltage transformerless multilevel inductive power transfer (IPT) system with excitation coils. The multilevel IPT system utilizes a cascaded H-bridge rectifier, half-bridge inverters, excitation coils, a transmitter coil, and a receiver coil to a grid-connected high-power IPT system. In practice, parameter inconsistencies among multiple excitation coils can lead to imbalanced output powers in the multilevel converter. Severely unbalanced output powers can lead to the failure of the voltage balance control in the multilevel converter. This study analyzes the voltage balance control range of the multilevel converter in relation to the parameter errors in the excitation coils. From this analysis, an acceptable parameter error rate for the fabrication of excitation coils is determined. A 6-level IPT system is evaluated using PLECS simulation results.