Aiming at the neutral point voltage imbalance of diode clamped three-level inverter(NPC),the causes and ef-fects of neutral point potential imbalance are analyzed firstly.Secondly,the neutral point potential control method based on re-dundant small vector can not suppress the neutral point potential fluctuation caused by medium vector in the region of high modulation ratio.A neutral point potential hybrid modulation strategy based on virtual space vector is proposed.In this method,the charge conservation method is used in the low modulation ratio range,the virtual space vector modulation is introduced in the high modulation ratio range,and the fuzzy controller is used to adjust the coefficient of the virtual small vector,so that it has the ability of closed-loop feedback control,and can effectively suppress the offset of the neutral point potential.
关键词
NPC三电平逆变器/虚拟空间矢量调制/中点电位平衡/模糊控制
Key words
NPC three-level inverter/virtual space vector modulation/neutral point voltage balance/fuzzy control
维普
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