Variable Timing Control for Wide Current Range Zero-Voltage Soft-Switching Inverters

This paper presents a variable timing controlled soft-switching inverter. The proposed timing control is based on a simple voltage sensing circuit that detects zero voltage crossing condition to determine the main switch turn-on time. The proposed technique can be applied to different types of zero-voltage switching type inverters. In this paper, the coupled-magnetic type soft-switching inverter is used as example to show the implementation method and its simulation and experimental results. A 5-kW hardware single-phase inverter prototype using CoolMOS as the main device and IGBT as the auxiliary device has been built and tested. Simulation results were well verified with experimental results. Efficiency was compared between the proposed variable timing and the conventional fixed-timing controlled inverters. Significant efficiency improvement was found at light-load conditions.