A High-Efficiency IPT System With Series-Capacitor Full-Bridge Configuration and Inverse Coupled Current Doubler Rectifier for High-Input, Low-Voltage, and High Output Current Applications

Different from the widely used high-voltage (HV) inductive power transfer (IPT) systems, the low-voltage IPT systems with HV input suffer from the following challenges: the high output current brings high conduction losses in the secondary side, especially at the receiver coil; and the HV conversion ratio, such as 400 V input and 24 V output, results in the difficulties in designing the compensation parameters and loosely coupled transformer. To overcome these issues, a novel IPT topology is proposed in this article by incorporating the series-capacitor full-bridge (SCFB) inverter and inverse coupled current doubler rectifier. Thus, the following three improvements are achieved: first, the voltage stress of three primary switches is reduced to half of the input voltage because of the special series capacitor structure. Second, the inherent one-fourth voltage conversion ratio is achieved and reduced greatly the difficulties in designing the compensation parameters. Third, the current flowing through rectifier circuit is reduced to half of conventional full-bridge rectifier. Furthermore, the LC-LCC compensation is employed for matching the proposed SCFB topology while a novel parameter optimization method is proposed to improve the conversion efficiency. To demonstrate the claimed features of the proposed solution, a 1.2 kW IPT prototype with 400 V input, constant voltage 24 V output is built and tested. The measured efficiency curve indicates that the efficiency from 8 to 50 A load keeps above 94.5% and peaks at 96.63%.