Switch count reduced structure for symmetric bi-directional multilevel inverter based on switch-diode-source cells

Abstract

Inverters as one of the most important elements of power systems have been profoundly developed in recent decades and their performance has attracted researches in control and structure point of view. In this study, a novel structure based on the switch-diode-source cell is proposed for a multilevel converter that is capable of bidirectional feeding. The proposed structure is presented for symmetrical mode and the number of power electronic devices is decreased in comparison with similar works. Considering recent proposed symmetrical structures, the proposed structure has the superior condition in terms of semiconductor switches and drivers count as well as switching loss. Also, total blocked voltage (TBV) of the proposed converter is compared with conventional and novel symmetrical converters. Then, switch costs of the proposed converter are compared with the structure that its TBV is the lowest. The performance of the proposed symmetrical seven-level converter is analysed and simulated in MATLAB/Simulink for both PWM and selective harmonic elimination switching methods. Not only the results are desirable, but also the experimental results of laboratory prototype validate the simulation results.