Modelling and design of new multilevel inverter for renewable energy systems with less number of unidirectional switches

Abstract

This paper presents, a unique topology for multilevel inverter based totally on cascaded connection of fundamental modules. The proposed circuit is able to operate for both symmetrical and asymmetric inverter, which can be used for fuel cell and photovoltaic systems. The magnitude of two dc sources in basic module can be adopted for symmetrical and asymmetrical structure. In the symmetrical multilevel inverter, the magnitude of dc source is identical for each module. However, the magnitude of dc source for basic modules is unequal in asymmetrical configuration and their magnitudes are achieved from binary and trinary progression. Comparison results prove that the proposed circuit requires a fewer number of components, reduced power loss and improve the efficiency of the inverter. Moreover, the total standing voltage on switches is acceptable compare to contemporary topologies. The proposed inverter can be implemented to low-medium power renewable energy systems. Simulation and experimental results for 11, 15 and 19-level inverters are analysed to validate the operation and performance of proposed topology.