基于零序电压注入的七电平有源中点钳位型逆变器中点电压平衡控制方法

A Neutral-point Potential Balancing Algorithm for Seven-level Active Neutral-point-clamped Inverters Based on Zero-sequence Voltage Injection

该文首先介绍七电平有源中点钳位型（seven-level active neutral-point-clamped inverter,ANPC-7L）逆变器及其悬浮电容电压控制问题;然后利用平均状态的概念将悬浮电容电压控制问题与母线中点电压控制问题进行解耦,建立基于零序电压注入的中点电压平衡控制模型,推导出中点电压的完全可控区域;最后,在此模型的基础上,提出一种试探–验证型的母线中点电压平衡控制实时算法。针对ANPC-7L逆变器的特殊性,对此方法进行进一步的优化,保证了串联管工作频率为逆变器输出频率,避免了相电压的多电平跳变。在一台380V/5k W的ANPC-7L逆变器上取得的实验结果证明了所提算法的有效性。

This paper introduced the seven-level Active Neutral-point-clamped inverter（ANPC-7 L） and the issue of its floating capacitors voltage controlling first. Then the paper decoupled the two issues of floating capacitors voltage controlling and neutral-point potential balancing by using the concept of average state, proposed a novel neutral-point potential balancing model based on zero-sequence voltage injection and deduced the full controllable region of neutral-point potential. Finally, a testing-verification type neutral-point potential balancing algorithm was proposed for real-time implementation based on the model. This algorithm was further optimized according to the particularity of ANPC-7 L inverter to ensure the operating frequency of the series device was the output frequency of the inverter and avoid the multi-level jumping of phase output voltage. The feasibility of the proposed algorithm is verified by experimental results from a 380 V/5 k W ANPC-7 L inverter.