Minimum neutral clamp capacitor design considering voltage saturation for a three-level inverter

A neutral point clamped inverter has a voltage fluctuation problem at the neutral point capacitor. This paper discusses the minimum value of the neutral point capacitor considering the voltage command saturation with the voltage fluctuation suppression control method. This paper clearly demonstrates the stable relationships among the input voltage, the output voltage and the capacitance value. In addition, the minimization design procedure of the capacitance value basis on this analysis is demonstrated. The validity of the design method is confirmed by experimental results.