Impact of Space Vector Modulation Strategies on the Reliability of Impedance-Source Inverters

Comparisons of different modulation strategies for Z-source/quasi-Z-source inverters (ZSI/qZSI) focused on voltage gains, switching losses, inductor current ripples, and harmonics. However, Pulse Width Modulation (PWM) strategies can affect voltage/current stresses and power losses on power devices. Therefore, thermal loading of the ZSI/qZSI inverters may be redistributed, and thus, the inverter lifetime may be affected. Hence, this paper evaluates the impact of three Space Vector Modulation (SVM) strategies on the qZSI reliability. More specifically, the maximum current stresses, power losses, thermal stresses, and the number of cycles to failure of the power switches are benchmarked. The evaluation enables identifying the most appropriate modulation strategy for Z-source inverters to achieve better performances in terms of efficiency and reliability. Simulation and experimental tests validate the theoretical analysis and comparison.