A Comparison Between Quasi-Z-Source Inverter and Active Quasi-Z-Source Inverter

This paper presents some comparative results between the three-phase quasi-Z source inverter (qZSI)and active quasi-Z source inverter (AqZSI). An improved PWM method is proposed for AqZSI. The voltage gain can be increased by using the shoot-through duty cycle and the switching ratio of the additional switch. Compared to qZSI, AqZSI with improved PWM strategy has a higher efficiency at the boost mode. Furthermore, AqZSI can be operated up to a higher modulation index and it boasts a lower inductor current ripple and reduced shoot-through current. The analysis of inverter and the improved PWM strategy are discussed. An experimental prototype with output power of 600 W is built to show the agreement of theory and measurement.