基于零序电压注入的五电平有源中点钳位型逆变器多目标优化控制策略

Multi-purpose Optimal Control Strategy of a Five-Level Active Neutral-Point Clamped Inverter Based on Zero-Sequence Voltage Injection

针对五电平有源中点钳位型逆变器的母线中点电压平衡、开关频率优化以及共模电压抑制等多目标优化问题展开研究,本文提出了一种基于零序电压注入的方法控制母线中点电压平衡,通过计算所有关键零序电压对应的中点电流,并从中选择最优的关键零序电压来产生所需的目标中点电流,从而使母线中点电压波动最小。在此基础上进一步限制注入的零序电压的取值范围,可使得串联双管工作在基频,同时限制共模电压的幅值不超过母线电压的1/4。实验结果表明了该控制策略的有效性。

A multi-purpose optimal control strategy of a five-level active neutral-point clamped(ANPC) inverter was studied in this paper, including the neutral-point(NP) potential balancing control, switching frequency optimization and common-mode voltage reduction. A NP potential balancing algorithm based on zero-sequence voltage injection was presented. By calculating the NP currents of all key zero-sequence voltages, the most appropriated zero-sequence voltage was selected to generate the demanded NP current, which can make the NP voltage ripple lowest. In addition, by further limiting the region of injected key zero-sequence voltages, the series connected IGBTs can operate at fundamental frequency and the amplitude of common-mode voltage can be reduced to a quarter of the DC-link voltage. Experimental results are presented to verify the validity of this control strategy.