An Improved One-to-Three WPT System With Tunable Compensation Network and Enhanced Pulse Density Voltage Control

To realize selective power transfer and output voltage regulation of inductor capacitor capacitor-series (LCC-S) compensated one-to-three wireless power transfer (WPT) system, a novel control strategy based on dual switch-controlled capacitor (DSCC) and enhanced pulse density voltage control (EPDVC) is proposed in this article. The improved series compensation network increases the selectivity of the receivers. Then, by introducing the DSCC into the LCC topology, both the load-independent current in the transmitting coil and the zero voltage switching (ZVS) of the inverter are maintained under different operating frequencies. Besides, the common phase shift modulation (PSM) used to regulate the output voltage is substituted by a novel pulse density control strategy to overcome the hard-switching issue when the system operates at light load. To verify the theoretical analysis, a 200-W prototype with 50-V input voltage is built and tested. The experimental results validate the selectivity of the one-to-three WPT system and the feasibility and stability of the proposed control strategy based on dual SCC and enhanced pulse density modulation (EPDM). The inverter achieves ZVS within the whole output power range under different operating frequencies, and the peak efficiency reaches 90.57% with resistive load.