A Hybrid Three-Phase AC/DC Power System for Low-Frequency Pulsed Load Applications

A hybrid three-phase ac/dc power system, which is composed of a diode-bridge rectifier and a two-stage ac-dc converter, is proposed in this article, for low-frequency pulsed load applications. With the proposed hybrid power system, the low-frequency pulsed load power is decoupled with the average power of the ac source, while the high-frequency harmonics induced by the diode-bridge rectifier is compensated by the ac-dc converter. Fault-tolerant operation is achieved with four possible operation modes of the proposed hybrid power system. Therefore, high reliability is achieved with these redundant operation modes. Operation principles, control methods, and design considerations of the hybrid ac/dc power system are analyzed in detail. An experimental prototype is built and tested to verify the effectiveness and feasibility of the proposed hybrid ac/dc circuit and its control strategy.