A Common-Mode Voltage Reduction PWM Strategy for Three-Phase Quasi-Z-Source Inverter With Optimized Switching Losses

Abstract

The application of the Z-source/quasi-Z-source inverter exacerbates the hazard of common mode voltage in motor drives or photovoltaic systems. The existing reduced common-mode voltage pulse width modulation (RCMV-PWM) technique applied to the Z-source/quasi-Z-source inverter has solved the problem of common mode voltage suppression to a certain extent, but its switching losses have not been optimized. In this paper, the existing Active zero-state PWM (AZSPWM) and remote state PWM (RSPWM) strategies in quasi-Z-source inverters are analyzed, and a new switching loss optimized common mode reduction modulation strategy is proposed. This algorithm does not change the original common-mode voltage suppression effect, while reducing the number of switching times in a switching period, thereby reducing the switching losses. By optimizing the shoot-through vector insertion method, the current stress of the switching device is reduced. The proposed modulation strategy does not affect the operating range and boost factor of the quasi-Z-source inverter OPWM strategy. The simulation results show that when the output power is 1kw, the proposed strategy can improve efficiency by at least 1% compared to the odd PWM(OPWM) strategy. Finally, A low-power test platform is built to verify the loss optimization effect.INDEX TERMS Common-mode voltage, Space vector, Switching loss optimization, Z-source inverter, odd PWM(OPWM).