A current-fed energy injection power converter for wireless power transfer applications

Modern wireless power transfer (WPT) technology emerges and advances with the advent of high frequency power electronic devices. However, the circuit topologies using these devices to generate high frequency currents or voltages remain much the same over the years. In this paper, a new type of current-fed power converter using energy injection approach is proposed for inductive power transfer (IPT) applications. The idea of the new converter comes from the study of three existing converters: the push pull resonant converter, the voltage fed energy injection converter, and the Class E converter. The circuit topology, basic operating principle and control methods of the new converter are explained and analyzed in details. Simulation and practical experiments are conducted for circuit verification and performance evaluation. The proposed converter can achieve full resonance and realize zero voltage switching (ZVS) with no dead time requirement. As a result, it has the potential to operate at much higher frequencies compared to the voltage fed energy injection converter which suffers from the deadline problem. Moreover, it overcomes the drawback of Class E converters which normally operate at open-loop with no feedback control from the resonant tank to coordinate the precise soft switching operation.