A Reduced Switch Count Three-Phase AC/AC Converter with Six IGBTs

Reducing the number of semiconductor switches in power electronic converters has been a continuing effort in recent years as a measure to enhance the system reliability and to decrease its size, weight, and component cost. For these reasons, a new reduced switch count three-phase ac/ac converter is being proposed. Being realized by only six active switches and anti-parallel diodes, the proposed converter topology employs the minimum number of semiconductor devices amongst the converters of its kind. It also features unity power factor, regenerative operation, pulse width modulated output voltage, and sinusoidal input current. The reduced number of switches results in a simplified associated gate drive circuit as well as cooling system which, in turn, may cut the overall manufacture cost, especially in low voltage and low power applications. The modulation scheme of the new converter is developed, and a control algorithm is proposed for the converter’s rectifier side. Moreover, an analysis is performed on the dc link capacitor sizing for the purposes of reducing dc link voltage ripple, balancing the input current, and lowering its THD. The simulation and experimental results corroborate the transient and steady state performance of the proposed converter topology.