Optimized discontinuous PWM algorithm with variable load power factor for multilevel inverters

Abstract

Recently, for multilevel inverters, the various PWM performances can be properly controlled by an offset controller in the carrier based PWM modulator. It has shown a generalised algorithm for realizing a discontinuous PWM technique for defined common mode. For applications with variable load power factor, reduction of switching losses can be improved if common mode is properly adjusted to avoid commutation instants at high current amplitudes. In the paper, the problem, how to design a common mode in DPWM for variable load power factor will be investigated. A novel carrier PWM algorithm capable of offset control will be presented. The advantage is simple and flexible algorithm. This algorithm will be utilized in designing an optimized discontinuous PWM for variable load power factor. The method is mathematically formulated and demonstrated by simulation results.