A new Space-Vector Pulse Width Modulation Algorithm for multilevel inverters

Abstract. This paper proposed a new Space Vector Pulse Width Modulation (SVPWM) algorithm for multi-level neutral point clamped inverter. The SVPWM method is an advanced, computation intensive PWM method and is also possibly the best among all the PWM techniques for variable frequency drive applications. The SVPWM involves the sector identification, determination of switching voltage vectors, switching vector sequence and dwelling time calculations. But as the level of the inverter increases, the sector identification, switching vector determination and dwelling time calculation becomes more complex. The computational complexity and execution time increases. In the proposed method, a correction to the duty cycles of reference vector is applied to easily identify the location of reference vector in each region of multi-level inverter. Then the appropriate switching sequence of the identified region and calculation of switching times for each state with the obtained duty cycles are estimated. The scheme can be extended to high-level inverters. Based on the above method the simulation results have been presented and analyzed for six-level and seven-level neutral point clamped inverters. The total harmonic distortion have been calculated and compared with lower levels also. The results have been good agreement with the published work