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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.

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Multilevel inverters are a new generation of DC–AC converters at medium and high voltage and power levels. In this paper, a new single-phase cascaded multilevel inverter is presented. For this purpose, a new basic cell is presented at first. Then, the new multilevel inverter structure is yielded by series connection of these cells. The proposed new cell is only capable of generating positive voltage levels, and therefore, to produce zero and negative voltage levels, the proposed structure is constructed based on H-bridge module. In order to reduce the maximum blocking voltage especially on H-bridge switches, the cascaded connection of the proposed converter is investigated. A comprehensive comparison is carried out between the proposed multilevel inverter with the classical and recently introduced structures in terms of the number of switching devices, the number of drivers, the total blocking voltage of the switches as well as the loss and efficiency. The accuracy of the proposed inverter’s performance is simulated in MATLAB/Simulink in symmetric and asymmetric topologies for a 17-level and 23-level output voltage respectively, and then evaluated by the laboratory prototype.

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