三电平零序分量注入载波调制及中点电位控制

Three-Level Carried Modulation Based on Zero-Sequence Voltage Injection and Control of Neutral Point Potential

针对传统的矢量合成法空间矢量调制逻辑复杂、运算量大的问题,研究了一种基于零序分量注入的中点钳位型三电平拓扑载波调制策略。推导并总结了参考电压在整个矢量空间下的零序分量表达式。数值仿真结果表明,将零序分量与参考电压叠加,可以实现与常规合成法等效的空间矢量调制。以负载电流方向和正负小矢量作用机制为依据,通过正负小矢量作用时间的调节,控制流入和流出母线中点的电流,可实现正负母线电压的平衡控制。搭建了三电平整流器正负母线不平衡测试环境,通过实验验证了中点电位控制方法的正确性和有效性。

A Carried modulation strategy of neural point clamped three-level topology based on zero sequence voltage injection is studied in this paper.The general formula for calculating the zero sequence voltage of the reference voltage in different sectors and modulation ratios is derived.Numerical simulation results show that superimposing the zero sequence voltage with the reference voltage can achieve space vector modulation equivalent to the conventional synthesis method.Based on the load current direction and the positive and negative small vector action mechanism,through the adjustment of the positive and negative small vector action time,the current flowing into and out of the neural point can be controlled.A three-level rectifier positive and negative bus unbalance test platform is built,and the correctness and effectiveness of the neutral point potential control algorithm are verified through experiments.