State space ZCS control for three-phase resonant converter

The paper presents design, modeling, control and implementation of a “long-pulse” three-phase resonant converter. A DQ equivalent circuit model of the resonant tank system is established first. Based on that, a model of the whole power supply and a state space multivariable feedback control has been developed. The soft switching, zero current switching (ZCS), is achieved by combining frequency and phase control together. An experimental prototype was designed and developed on a small scale. Experimental results confirm the expectations from the simulation study and validate the feasibility of the converter.