Novel topology and modulation strategy to asymmetric multilevel inverter

When the traditional multilevel inverter is applied to high voltage level, the number of power supply and switch tube required is large, and the topology structure is also more complex. To solve the above problems, a new asymmetric multilevel inverter topology was proposed, which uses three asymmetric independent power supplies. Compared with the traditional topology, under the condition of outputting fifteen level voltage, in this topology less switching tube devices were used, the topology structure was simplified and the actual cost was reduced. An improved carrier amplitude shift modulation strategy was used to modulate the new asymmetric topology structure so that it can normally output a fifteen level voltage waveform. The method maintains the advantages of simple carrier amplitude shift modulation method and low harmonic content, and reduces the use of carrier number. Finally, simulation analysis and experimental verification of the proposed topology and its modulation strategy were carried out. The simulation and experimental results show that the proposed topology and its modulation strategy are correct, feasible and have good dynamic performance. © 2023 Editorial Department of Electric Machines and Control. All rights reserved.