A high-power-factor, three-phase isolated AC-DC converter using high-frequency current injection

A single-stage, three-phase ac-to-dc converter topology is proposed for high-frequency power supply applications. The principal features of the circuit include continuous current operation of the three ac input inductors, inherent shaping of the input currents, resulting in high power factor, a transformer isolated output, and only two active devices are required, both soft-switched. Resonant conversion techniques are used, and a high power factor is achieved by injecting high-frequency currents into the three-phase rectifier, producing a high frequency modulation of the rectifier input voltages. The current injection principle is explained and the system operation is confirmed by a combination of simulation and experimental results.