Double Modulation Technique for a ZVS Self-Oscillating Half-Bridge Inverter

Abstract

This paper proposes a simple power control scheme in order to convert the conventional nonadjustable self-oscillating half-bridge series-resonant inverter into an adjustable one. The proposed topology, based on a self-oscillating structure, can automatically ensure the turning on and the turning off of the switches without any external control. A simple modification in one of the gate drivers side circuit allows one to adjust the output power without compromising the simplicity, reliability, and low cost, which characterize the self-oscillating half-bridge inverter. Moreover, this topology achieves a stable and efficient zero-voltage switching over the entire operating range with a constant switching frequency; as a consequence, the inverter overall efficiency is significantly improved. Experimental results are proposed to validate the analysis and to demonstrate the performance of the proposed control scheme.