Neutral point voltage feedback control based on zero sequence injection for NPC three-level converter

作者：Xie Luyao^*; Jin Xinmin; Wu Xuezhi; Yin Jingyuan; Tong Yibin

来源：Transactions of China Electrotechnical Society, 2012, 27(12): 117-128.

• Neutral point balance
• Neutral point clamps
• Neutral points
• Sinusoidal pulse width modulation
• Three-level converters
• Unbalance compensation
• Zero sequence voltage

Output AC voltage compensation and neutral point voltage feedback control under neutral point voltage unbalanced conditions are discussed. A neutral point voltage feedback control strategy based on zero sequence injection is proposed. Using this strategy, not only output voltage can be guaranteed no distortion but also neutral point voltage can be adjusted at will. The modulation strategy is based on SPWM principal, so it's very simple to realize, and suitable for enhancing traditional neutral point balance control or applications where need to control up and down DC link voltage separately. The neutral point current control ability of the strategy is given, and the neutral point voltage low frequency fluctuation problem is also analyzed. Simulation and experimental results verify the correctness of this theory.

• 出版日期2012
• 单位北京交通大学