Control and Soft Switching Analysis of a Single-Stage Wireless DC Motor Drive System

This paper proposes a wireless DC motor drive system to solve the wire wear problems caused by slip rings and cables. The dual-bridge structure is adopted to integrate both power supply and motor control functions, without the need for a motor drive inverter. A primary-side fixed frequency and duty cycle and secondary-side fixed off-time control is proposed, eliminating the primary and secondary-side communication and guaranteeing soft switching for active rectifiers under all load conditions. The effect of frequency deviation on the inverter’s soft switching is analyzed and the soft switching boundary is given. Finally, a 200 W prototype has been built to verify the above analysis, and a maximum DC/DC efficiency of 96.56% has been achieved.