High-efficiency voltage source converter with low switching power losses for application in islanded microgrids

摘要

In the conventional inverter, the switching power losses cause the inverter efficiency to decrease at high switching frequencies. In this study, a new structure of a single-phase voltage-source inverter with low switching losses is proposed, for application in islanded AC grids. This converter is composed of two single-phase series inverters, with different switching frequencies. The main feature of the proposed converter is that, the total losses of the proposed converter are fewer than the total losses of a conventional single-phase inverter, at high switching frequencies. The proposed converter is designed by the appropriate power transistors in the market. By providing a suitable method for calculating the transistor power losses, the switching and conduction losses of the proposed converter are calculated, and compared with losses of a conventional single-phase inverter. The mathematical model of the proposed converter is derived and used along with root-locus and frequency-response analysis, for designing the controllers. The performance of the proposed converter has been assessed using the simulation studies in MATLAB/SIMULINK software environment.