Modified SVPWM for Trans-Z-Source Inverter-based PV Systems

In this paper, a modified space vector PWM is presented for Trans-Z-source inverter -based grid -connected photovoltaic systems. In this method, the shoot-through states are added which bring outstanding merits like lower total harmonic distortion, lower voltage stress (higher reliability) and higher voltage boost gain, as opposed to traditional methods. Plus, the Trans- Z-source inverter has an ideal transformer and a capacitor, which can overcome limitations of traditional voltage-source inverters and z-source inverters. Buck/boost feature, fewer passive elements, and higher voltage boost gain are its advantages. To evaluate the effectiveness of the proposed switching method, the photovoltaic system is analyzed in three different cases: based on the voltage-source inverter with carrier-based PWM, based on the trans-z-source inverter with maximum constant boost control and based on the trans-z-source inverter with modified space vector PWM. Simulation results confirm the superiority of the proposed photovoltaic system with the modified space vector PWM in terms of the power quality and the voltage stress.

Keywords:

PV System , Modified SVPWM , Trans-Z-Source Inverter , THD.