A quantitative harmonics analysis approach for sinusoidal pulse-width-modulation based Z-source inverters

Abstract

The shoot-through (ST) states are essential for the operation of sinusoidal pulse-width-modulation (SPWM) based Z-source inverters. However, the insertion of shoot-through state unavoidably leads to output harmonics which is greatly affected by its distribution, especially for bipolar modulation schemes. With quantitative analysis, this paper investigates the mathematical relationship between the output harmonics and shoot-through states for single-phase Z-source inverters. A modified double-Fourier-transformation-based calculation scheme is proposed to estimate the output harmonics with different shoot-through states insertion methods. Simulations and hardware experiments with a 200 W single-phase Z-source converter under two bipolar modulation control methods verified the accuracy of the proposed theory. The quantitative analysis would be helpful for the design of Z-source converter's control strategy and modulation scheme.