A novel half-bridge resonant inverter having load-freewheeling modes

This work presents a new circuit topology and its digital control scheme of the half-bridge resonant inverter. As the proposed half-bridge inverter can be operated in the load-freewheeling modes, pulse width modulation (PWM) control method can be used for the output power control. The proposed half-bridge inverter should keep unity output displacement factor under the load-impedance varying conditions, if a new PWM control scheme based on the resonant frequency tracking algorithm is adopted. In this paper, the operation principle, electrical characteristics, and detailed digital control scheme of the proposed half-bridge resonant inverter are described. Experimental results of the prototype experimental setup to verify the validity of the proposed half-bridge resonant inverter are presented and discussed.