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为了平衡三相三电平中点箝位型逆变器直流侧电容电压，该文提出一种基于中点电流极性判断的电容电压平衡算法，通过在三相调制波上叠加高频的均压调节量来均衡电容电压，能有效地避免对输出电压波形质量的影响。采用七段式开关序列和详细的数学解析对该中点电位平衡方法的可行性进行研究，推导了不同调制度和功率因数下的均压特性，从而揭示了该方法的均压范围和影响因素。实验结果验证了理论分析的正确性和均压控制方法的有效性。“,”In order to solve the neutral-point voltage unbalancing problem for the three-level neutral-point clamped (NPC) inverter, a novel voltage balance control strategy based on judging the polarity of the neutral-point current was proposed. The proposed method can effectively avoid the influence on the waveform quality of the output voltage by adding the high frequency voltage regulation on the three phase modulation signals. The feasibility of the proposed control algorithm was studied via the seven-segment switching sequences and detailed mathematical calculation. The voltage balancing characteristics of different modulation index and power factor were derived, which revealed the effective range and the influence factors of the method. Experimental results were presented to verify the validity of the theoretical analysis and the effectiveness of the proposed strategy.