Research On DC Capacitor Potential Of 5-level ANPC Inverter

This paper analyzes the root cause of midpoint voltage fluctuation in five-level active midpoint clamp (ANPC) inverter, and proposes a midpoint potential balancing method controlled by adding hardware circuit. Compared with the software method based on zero-sequence injection SPWM and redundant small vector allocation SVPWM, this method can simply realize the balance control of midpoint potential. The calculation is small and easy to implement. In this paper, the on-off control of the inverter switching tube is realized by the modulation method of carrier phase shift. Through simulation and experiment, it is proved that the control method proposed in this paper can simultaneously suppress the midpoint potential fluctuation of the five-level ANPC inverter, which has strong engineering application value.