Voltage-Source PWM Rectifier–Inverter Based on Direct Power Control and Its Operation Characteristics

This paper describes a novel control strategy of direct power-control-based voltage-source pulsewidth modulation (PWM) rectifier-inverter. The key of this strategy is direct selection of a switching state of the PWM rectifier-inverter on basis of instantaneous power errors. A relationship between the instantaneous power and the switching state of the PWM rectifier-inverter is theoretically analyzed, which is essential to compose a switching-state table. Effectiveness of the proposed technique is examined through several experimental tests, using a 1.6-kW prototype. As a result, unity power factor operation is achieved by the proposed method, and the output currents are confirmed to be sinusoidal waveforms without large distortion under balanced and unbalanced power-source condition.