Improved configuration for symmetric and asymmetric multilevel inverters with reduced number of circuit devices

In this paper, a topology developed for multilevel voltage source inverters is proposed. The suggested modular configuration consists of several series-connected units, which can be applied as symmetric and asymmetric inverters. In the asymmetric mode, different solutions are suggested to generate an increased number of output voltage levels. In multilevel inverters, the number of required circuit elements determines the total cost, circuit size, installation area, complexity of control scheme and reliability of the inverters. The comparison study among the proposed inverter by considering all the presented algorithms for it, cascaded H-bridge (CHB) inverter and recently proposed converters, confirms that the proposed inverter uses a reduced number of circuit elements. In order to show the practicability of the proposed converter, a prototype of the proposed structure is implemented and tested. The simulation and experimental results are in good agreement with each other, indicating the effectiveness of the proposed inverter.     

A developed single-phase cascaded multilevel inverter with reduced number of circuit devices

In this paper, an advanced configuration for multilevel voltage source inverters is proposed. The proposed topology can be used as symmetric and asymmetric inverter. In asymmetric mode, DC sources’ magnitudes are defined in a way that the number of output voltage levels gets more than the case when the symmetrical DC sources are applied. In this regard, to calculate the magnitudes of required DC voltage sources, several different solutions are proposed. In multilevel inverters, the overall cost, circuit size and so installation area, complexity of control scheme and reliability are directly dependent on the number of circuit devices needed. The provided comparison study among suggested inverter in all defined solutions, CHB and recently proposed converters validates that the proposed modular inverter uses reduced number of circuit devices. The provided simulation and experimental results confirm the feasibility of the proposed structure and show that the obtained results are in good agreements.