A New Modular-Based Three-Phase Multilevel Inverter with Reduced Active Power Switches and conduction Loss

ower loss in multilevel converters has an essential role in many applications, especially in renewable energy systems. In this paper, a new topology with a reduced number of semiconductor power switches for the three phase multilevel inverter (MLI) has been proposed. This topology includes only equivalent power supplies which are connected in series to produce the output levels. Without using more than two series-connected power switches in each leg of the proposed MLI, the output levels are extended and therefore the conduction loss is reduced. The basic structure of the proposed topology is constructed of a five-level inverter which is connected in three legs configuration for three-phase applications. Furthermore, the modular configuration of the proposed MLI is constructed by adding the basic cells to the proposed five-level inverter and the output can be extended to more levels with the simple modular connection. The proposed modular multilevel inverter (MMLI) is simulated with sinusoidal pulse width modulation (SPWM) and its main features such as the number of power devices, switching and also conduction losses are investigated carefully and compared with reported ones. Moreover, the performance of this inverter has been verified by a three-phase five-level laboratory (1KVA/400v) prototype.