Maximum boost control of Cascaded Z-Source inverter with third harmonic injection

The Characteristics of Cascaded Z-Source inverter and traditional Control strategy are analysed, and a maximum boost control strategy is proposed in this paper. Based on SPWM with third harmonic injection, all the zero vector states are replaced by shoot-through states, it can reduce the switching frequency as well as improve the shoot through duty cycle effectively, then increases the boost factor. Theoretical analysis is made, the formulas are deduced. Compared to the traditional Control strategy, under the same times of the voltage, maximum boost control with third harmonic injection improves the modulation index significantly, thus extending the input range of the cascaded Z-source inverter. Simulation and experimental results are given to demonstrate the new features of the improved.