Research on a soft-start method for LCC-LCC compensated bidirectional wireless power transfer system

Abstract

The increased popularity of electric vehicles and the pursuit of user convenience makes bidirectional wireless power transfer (BWPT) an attractive technology for charging batteries. To improve the transmission efficiency of BWPT and limit the external radiated magnetic field, it is necessary to ensure the zero-voltage switching (ZVS) operation of the converter on the transmitter-side and limit the transient start-up current of the inverter when the system is working. To solve this problem, this paper proposes a soft-start modulation strategy based on an H-bridge inverter on the transmitter-side. First, the circular characteristics of dual LCC compensation topology are analysed based on an equivalent circuit. Secondly, according to the characteristics of the input impedance angle and current of the transmitter-side, a soft-start control method combining frequency and phase shift control is proposed. Finally, the feasibility of the proposed soft-start modulation strategy is verified on a prototype.