Neutral-Point-Cl amped Converter underNeutral Point Imbalance Condition

Imbalance oftheneutral-point potential inthree-level neutral-point-clamped converter mayappearinsomeoperating conditions. Thispaperanalyzes thevoltage distortion caused by theimbalance oftheneutral pointpotential ina three-level neutral-point-clamped converter, andalsodescribes thePWM methodtogenerate thelow-frequency harmonics-free output voltages evenundertheimbalanced condition. Furthermore, the proposed PWM methodhastheadvantages intermsofthe high-frequency harmonics, since three voltage vectors neartothe reference vector areused.Simulation andexperimental results verify thefeasibility oftheproposed method. three-level neutral-point-clamped converter