New Topology of Three-phase Three voltage levels inverter using a novel precalculated switching method

This paper presents a new topology of three phases voltage with three levels inverter (NTTPTVLI) using precalculated voltage levels and switching angles. We have developed a computing model which calculates the voltage levels and the switching angles only in the one-sixth of period. Voltage levels and switching angles are deduced in the remaining five- sixth of period by symmetries. The voltage levels and the switching angles are precalculated so as to eliminate a maximum number of successive low ranked harmonics for a given fundamental magnitude voltage and a given number of switching per one-sixth period. This approach allows us to use, in the same time, a reduced number of switching per period and a small capacitance passive filter. Consequently, the total harmonics distortion (THD) in the output voltage, the power loses in the inverter are also reduced. Simulation results show a substantial reduction of the (THD) rate and the effectiveness of the proposed method.