Design of a Single‐Phase Quasi‐Z‐Source Asymmetric Cascaded Half‐Bridge Multilevel Inverter

In this paper, a single‐phase quasi‐z‐source asymmetric cascaded half‐bridge multilevel inverter (qZS‐ACHBMLI) is proposed, featuring a novel control scheme to achieve desired AC output voltage levels. The proposed inverter has a modular design, allowing for easy extension of output voltage levels by adding additional power modules. Unlike other multilevel inverters (MLIs), the proposed topology is designed as a half‐bridge, so it is possible to generate an AC output voltage at the desired voltage level with a minimum number of switches. This reduces the size, cost, and complexity of the circuit. Besides, the proposed control algorithm enables the generation of negative voltage levels with a half‐bridge polarity changer circuit. However, in the negative half cycle, the output voltage drops to zero as the polarity changer circuit provides a shoot‐through (ST) condition to increase the output voltage. The robustness of the proposed topology and control method is validated through experimental results obtained from a 500 W, five‐level qZS‐ACHBMLI prototype, controlled by a 32‐bit NUCLEO‐F401RE microcontroller. The experimental findings demonstrate a significant improvement in energy efficiency compared with competing topologies.