VSI-PWM rectifier/inverter system with a reduced switch count

A current-controlled VSI-PWM rectifier and inverter with capacitor de link is regarded as one of the most important structures for three-phase to three-phase power conversion, This type of converter normally requires twelve switches for a rectifier and inverter composed of self turnoff switch such as a bipolar transistor or an IGBT with an anti-parallel diode, In this paper, a new three-phase to three-phase converter for ac motor drives is proposed, The proposed converter employs only eight switches and has the capability of delivering sinusoidal input currents with unity power factor and bidirectional power flow, This paper describes the feasibility and the operational limitations of the proposed structure, A mathematical model of the system is derived using the generalized modulation theory and experimental results for steady state and dynamic behavior are presented to verify the developed model.