Implementation of Z-Source Inverter for Motor Drive Application

Abstract

Traditional converters as voltage source converter and current source converter has their own conceptual limitation as voltage source converter provides step down output compared to input line voltage as operated in inverter mode, on other hand current source converter provides step up output compared to input line voltage when operated in inverter mode. It means that they can’t be operated in both of the mode without additional power converter. To overcome these limitations Z-source concept can be applied. The impedance source power converter (Zsource converter) contains a unique impedance network to couple the converter main circuit to power source, thus provides unique features that can’t be obtained in the traditional voltage source inverter(VSI) and current source inverter(CSI).The Z-source inverter(ZSI) overcomes the conceptual and theoretical barrier and limitations of traditional VSI and CSI. This Z-source concept can be applied for motor drive application. By controlling shoot-through duty cycle, the Z-source can produce desired output as voltage even greater than the line voltage. As a result, the ZSI system provides ride-through capability during voltage segs, reduce line harmonics, improve the power factor and extends output voltage range.