Half-cycle control of the parallel resonant converter operated as a high power factor rectifier

A half-cycle control technique for the parallel resonant power converter operated as a high power factor rectifier is introduced in this paper. Switching of the bridge power transistors is determined such that the bridge input current averaged over a half switching cycle exactly follows the reference proportional to the input voltage. Zero current switching and below-resonance operation are guaranteed, while control of the input current is the fastest possible, regardless of the operating point. In contrast to conventional regulators, the performance is preserved under both small and large signal variations, and also for large variations of the power-stage parameter values. Fast response, stability and robustness are experimentally verified on a 1.4 kW prototype.