Auto-tuning controller design of class E inverter with resonant components varying

Class E resonant power amplifier (or inverter) is often applied to design a high frequency switching power converter. The zero voltage switching (ZVS) or zero current switching (ZCS) operation leads the converter to high converting efficiency even the converter works at high frequency. Theoretically, with a high speed power transistor, the class E amplifier can work from several megahertz´s to dozen of megahertz´s. While the resonant components of class E inverter are varying, the ZVS operation will be shifting around the dominant operating point. In this paper, we propose an auto-tuning control method to overcome the components shifting problem. Also, the practical control system is implemented by FPGA module board. The prototypical circuit of 150 W, 1.2 MHz parallel driving Class E systems with full digitized controller has been accomplished to verify the proposed control method and performance.