三电平ANPC逆变器变虚拟空间矢量控制策略

Virtual Space Vector Pulse Width Modulation Control Strategy for Three-level ANPC Inverter

针对三电平有源中点箝位(ANPC)逆变器存在的中点电压平衡问题,提出一种基于虚拟空间矢量脉宽调制(VSVPWM)的改进控制策略。通过在原虚拟空间矢量开关序列基础上,根据开关损耗特点重新优化整合,并实时采样逆变器的中点电压偏移值与三相负载电流大小,根据两者对应关系动态选择相应开关序列,实现中点电压平衡控制目标。在满足中点电压平衡的同时,相比较传统VSVPWM策略的九段式开关序列,采用的改进式开关序列有效减小了每个开关周期内功率器件的切换次数,降低了逆变器的导通与关断损耗。最后通过Matlab/Simulink仿真并搭建实验平台验证了控制策略的有效性。

Considering the neutral-point potential balancing problem existing in the active neutral-point clamped（ANPC） inverter, an improved modulation control strategy based on virtual space vector pulse width modulation （VSVPWM） is proposed.According to the performance of switching loss,the original switching sequence is reopdmized.The neutral- point potential offset and three-phase load currents of the inverter are sampled, the switching sequence is selected dy- namically by the relationship between neutral-point potential offset and currents.These can achieve the neutral-point potential balancing.However,compared with the nine-stage switching sequence in traditional VSVPWM,the improved switching sequence is used to reduce the switching times in each switching cycle.The switching loss of the inverter is reduced.Simulation and experimental results are provided to verify the effectiveness of the proposed control strategy.