Research On Neutral Point Potential Balancing SVPWM In Three-Level Neutral-Point-Clamped Inverter

The midpoint of the DC side voltage imbalance is the outstanding problems of the neutral point clamped three-level inverter, the problem that rooted in the neutral point clamped three-level inverter topology is the mid-point clamped (NPC) three-level inverter inherent problem. The midpoint potential imbalance may bring problems such as switching devices’ turn-off voltage increases, the output voltage waveform distortion, harmonic component increases and other hazards, so the impact of neutral point clamped three-level inverter applications constraints. In this paper, reason of three-level inverter midpoint potential imbalance is analyzed. And three-level space vector modulation (SVPWM) on fuzzy control is introduced.In this paper, reason of three-level inverter midpoint potential imbalance is analyzed. And a three-level space vector modulation (SVPWM) strategy based on the design of the mid-point potential balancing scheme based on fuzzy control is introduced.First, the neutral point clamped three-level inverter topology, operation principle, to establish the mathematical model of the neutral point clamped three-level inverter were introduced. And three-level inverter space vector modulation strategy is studied and analyzed.Secondly, the causes of midpoint potential imbalance of the neutral point clamped three-level inverter controled by space vector modulation strategy the is studied. The equilibrium condition of midpoint potential is gave out. Mid-point potential balancing scheme based on fuzzy control is designed.Finally, on the basis of theoretical analysis, the effectiveness of midpoint of the neutral point clamped three-level inverter voltage balance SVPWM modulation method is verbified by simulation results.