Research on Input-Parallel Single-Switch WPT System With Load-Independent Constant Voltage Output

Single-switch circuit (SSC) in wireless power transfer (WPT) technology shows excellent performance with its simple topology. However, in higher power applications, limitation of power capacity has become the main bottleneck for SSC-WPT technology. Therefore, a research of multiple SSCs connected in parallel in WPT systems has received more attention. In this article, an input-parallel single-switch circuit (IPSSC) based on a compact decoupled coupler is proposed in WPT systems to upgrade the power capacity. Meanwhile, parallel-LCL (P-LCL) compensated network is applied to realize constant voltage output (CVO) independent of the load. Moreover, a novel method of parameter calculation using high-order harmonics approximation is proposed for IPSSC-WPT systems, which can realize precise margin of zero-voltage switching (ZVS). The experimental results of a 1-kW prototype with an output voltage of 150 V are in agreement with the theoretical analysis well.