An Asymmetrical Cascaded Single-phase quasi Z-Source Multilevel Inverter with Reduced Number of Switches and Lower THD

This paper presents a modified quasi Z-source inverter with a less number of switching devices. In a wide range of modulation index, the output voltage of the proposed inverter has a lower THD compared to Quasi-Z source cascade multilevel inverter (qZS-CMI). To illustrate the superior advantages of the proposed topology over the conventional qZS-CMI, both inverters are studied for the same condition. Various modulation indexes are considered and performance of both topologies are analyzed. By varying the modulation index in both inverters, different voltage amplitudes can be achieved. The obtained results from several simulations demonstrate the higher performance of the proposed topology with lower THD in the output voltage. The most important feature of the proposed topology can be mentioned as reducing the number of semiconductor devices, which leads to reducing the implementation cost of the inverter. Increase reliability and efficiency are the other valuable advantages of proposed structure compared to previous works. A modulation technique based on the alternative phase opposition disposition (APOD) method is adapted, and control system, also, is simplified because of reducing in the number of switches. Comparative study and simulation results are provided to validate the effectiveness of the proposed topology.