有源钳位三电平变频器调制策略及损耗分析

Modulation Strategy and Loss Analysis of Active Neutral Point Clamped Three-level Converter

传统中点钳位(NPC)三电平变频器存在功率器件损耗不平衡问题,导致部分功率器件发热严重,限制了变频器容量和功率器件开关频率的提升。采用有源钳位(ANPC)三电平拓扑结构可产生冗余零电压状态输出实现功率器件损耗平衡。分析了ANPC三电平变频器的工作原理及其换流方式1和方式2下功率器件的工作特性,并给出了两者PWM脉冲生成的方法,在单周期切换模式下ANPC三电平变频器功率器件损耗具有较好的平衡能力。实验验证了两种换流方式下调制策略的正确性以及单周期切换模式的有效性。

Traditional neutral point clamped （NPC） three-level converter has loss unbalance problem and thus some of the power devices endure heat severely which limits the power capability and switching frequency. However, this problem can be overcomed by active NPC topology since it has redundancy zero voltage output states. Operation principle of ANPC three-level converter was analyzed as well as power devicels working characteristics under commutation type 1 and type 2. The PWM strategies of these two commutation types were al- so introduced and the ANPC three-level converter has a better loss balance ability compared with NPC under commutation type switching mode. Experimental results verify the validity of the two type modulation strategies and the commutation switching mode.