有源钳位三电平变频器改进SVPWM策略

中点钳位(NPC)三电平变频器存在功率器件损耗不平衡问题,部分器件发热严重,限制了变频器容量和开关频率的提升,有源中点钳位(ANPC)三电平变频器通过不同的零电压输出状态可以平衡功率器件的损耗。通过选取不同的冗余零状态,提出一种适用于ANPC三电平变频器、可以平衡功率器件损耗的改进空间矢量调制(SVPWM)算法。对所提SVPWM算法和传统正弦矢量脉宽调制(SPWM)算法进行仿真对比,分析功率器件损耗分布情况,结果表明所提方法可以平衡功率器件的损耗,提高变频器的容量和开关频率。另外,和SPWM算法相比,采用SVPWM算法输出电压可以提高15%,电流谐波畸变率会有所降低,最后通过实验验证了所提算法的正确性。

Improved SVPWM Strategies for Active Neutral Point Clamped Converters

Uneven distributions exist among the power devices in traditional neutral point clamped (NPC) three-level converter. The severe heat of some devices limits the output power and switching frequency. Active neutral point clamped (ANPC) three-level converter can balance the loss distribution that benefits from the addition of more zero switching states. Based on the selection of primary and secondary zero states, this paper presents an improved SVPWM method for ANPC three-level converte. Compared with traditional SPWM, the improved SVPWM method can balance the loss distribution, and improve the capability and switching frequency of the converter. In addition, 15%voltage conversion ratio and lower harmonic distortion can be achieved. Finally, experimental results verify the effectiveness of the design method.