Impedance Tuning Control and Synchronization Technique for Semi-Bridgeless Active Rectifier of IPT System in EV Applications

This paper proposes an impedance tuning control for a semi-bridgeless active rectifier (SBAR) of inductive power transfer (IPT) systems in electric vehicle (EV) applications. The proposed control can compensate for impedance mismatch which is caused by the change in parking position through adjusting turn-on point and duty ratio of SBAR. The operating principle is explained by the analysis of frequency characteristics and equivalent impedances. In addition, a rising edge detection technique of SBAR switch voltage is proposed to synchronize SBAR with the primary-side IPT system using minimal primary-side information, even if a variable frequency control is applied. Analysis results and validity of the proposed impedance tuning control are experimentally verified with a 3.3 kW laboratory prototype of the IPT system with SBAR.