三电平ANPC逆变器中点电压平衡和开关损耗减小的SVM控制策略

A Space Vector Modulation Scheme for Three-level ANPC Inverters With Neutral-point Potential Balancing and Switching Loss Reduction

有源中点钳位型拓扑通过选择冗余开关状态和不同的电流通路能够有效控制器件的损耗平衡。论文对三电平有源中点钳位型逆变器中点电压平衡和开关损耗减少的控制策略进行研究,提出一种中点电压平衡和减小损耗的三电平空间矢量调制方法。将虚拟中矢量重新定义,新的虚拟中矢量由原中矢量和邻近的两对小矢量合成,因此参考矢量在空间矢量图的任何区域都有两个成对的正负小矢量参与合成,其中一个优先用于控制中点电压的平衡,另外一个可以用于其他控制目标。在每个开关周期内根据中点电压波动和开关序列选择合适的小矢量,在控制中点电压平衡的基础上有效地减小了器件的开关损耗。最后搭建三电平ANPC逆变器仿真和实验平台对提出的控制策略进行验证,实验结果表明了控制策略的有效性。

The active neutral point clamped（ANPC） topology enable additional switch states and commutations compared to the neutral point clamped（NPC） topology. ANPC topology can overcome disadvantages of unequal semiconductor loss distribution in NPC topology. This paper investigated the control strategy of the neutral-point potential（NP） balancing and the switching loss（SL） reduction for three-level ANPC inverters. An novel three-level space vector pulse width modulation（SVM） was proposed to control the NP imbalance and to reduce the SL simultaneously. The novel virtual medium vectors were redefined, which were synthesized by the original medium vector and the adjacent two pairs of small vectors. Therefore, using the proposed VSVM, there are two pairs of small vectors in any region of the space vector diagram, which one pair of small vectors can be used to control the NP, and another pair of small vectors can be used for reducing the SL. The coordinately selected small vectors consider both the NP charge and the pulse sequence, so that the minimized NP ripple and switching events are guaranteed in one switching cycle. The simulation and experimental results are provided to verify the effectiveness of the proposed control strategy.