An DPWM for Active DC-Link Type Quasi-Z-Source Inverter to Reduce Component Voltage Rating

Abstract

The conventional DC-link type quasi-Z-source inverter has been known as a buck–boost inverter with a low component voltage rating. This paper proposes an active DC-link type quasi-Z-source inverter by adding one active switch and one diode to the impedance-source network to enhance the voltage gain of the inverter. As a result, the component voltage rating of the inverter is significantly reduced, which is demonstrated through some comparisons between the proposed topology and others. A discontinuous pulse width modulation (DPWM) scheme is proposed to control the inverter, which reduces the number of commutations compared to the traditional strategy. Under this approach, the insertion of a shoot-through state does not cause any extra commutations compared to the conventional voltage-source inverter. Details about control implementation, steady-state analysis, and design guidelines are also presented in this paper. Simulation and a laboratory prototype have been built to test the proposed inverter. Both buck and boost operations of the proposed inverter are implemented to validate the performance of the inverter.