A Novel Nine-Switch PWM Rectifier-Inverter Topology For Three-Phase UPS Applications

A novel three-phase PWM rectifier-inverter topology for UPS applications is proposed in this paper. The topology uses only nine IGBT devices for AC/AC conversion through a quasi dc link circuit. This converter topology features sinusoidal inputs and outputs, unity input power factor, and more importantly, low manufacturing cost. The operating principle of the converter is elaborated and a novel modulation scheme is presented. The performance of the proposed converter is verified by experiments on a 5kVA prototyping UPS system.