THD Minimization in a Five-Phase Five-Level VSI Using a Novel SVPWM Technique

Abstract

In the last decade, multiphase motors have been extensively used due to development of power electronic converters and reduction of total prices. The advantages of multiphase motors can be mentioned as less torque ripple, high power density, high efficiency and better reliability at the moment a phase is cut off. Harmonic is one of the most important issues in designing electronic power converters, and its reduction significantly improves efficiency, load performance and reduces electromagnetic disturbances. One of the most widely used method for decreasing harmonic contents of such inverters is using multilevel techniques. Until now, different switching algorithms are presented to diminish low-order harmonics and total harmonic distortion (THD). Hence, in this paper, a novel space vector pulse width modulation (SVPWM switching technique) is presented in a five-phase voltage source inverter (VSI in order to reduce THD and low-order harmonics with fundamental voltage amplitude fixation). Subspace election for determination of switching time is based on smallest triangle which is surrounding the reference vector vertex. In this method, the zero vectors will be eliminated in large amplitude modulation index. Genetic algorithm (GA) is utilized in optimization process to find the best applying time sequence in switching pattern for minimizing THD and switching losses. Simulation results are also provided for verification of proposed algorithm.