Novel K-Type Multilevel Inverter With Reduced Components and Self-Balance

Abstract

This article proposed a single-source multilevel inverter (MLI) based on the novel K-type unit (KTU). The 13-level topology with two KTUs and 1.5 voltage gain is first introduced, and its operation modes at different output levels are described in this article. The two capacitors in series connection with each KTU can get self-voltage balance due to their symmetric operation in a cycle, reducing the complexity of control compared with conventional MLIs. The analysis of self-balance and capacitance calculation are given in detail. Afterward, the single-source generalized structure equipped with more KTUs is presented for increasing output levels. The output levels are significantly increased with additional KTUs, and the voltage gain rises as well. Moreover, through the comparative study against other MLI topologies proposed in recent years, the advantages of the proposed KTU topology are indicated in the aspects for reduced components, self-balance, voltage stress, and overall cost. Finally, the 13-level simulation and 1-kVA experimental prototype with fundamental frequency modulation (FFM) are implemented to verify the feasibility and transient performance of the proposed topology.