李杰 徐渊 宋文祥

摘要：针对降低功率器件的开关频率而带来电流谐波较大的问题，提出采用特殊设计的优化脉冲调制策略。通过深入研究五电平有源箝位（ANPC）逆变器电流谐波最小脉冲宽度调制（PWM）策略，设计一种基于遗传算法（GA）的优化脉冲调制开关角计算方案，该方案相比传统牛顿迭代法具有更好的电流谐波特性;对于五电平有源箝位逆变器存在的悬浮电容电压波动问题，提出一种基于冗余开关状态切换的悬浮电容电压滞环控制策略，通过合理分配冗余开关状态的作用时间，能够将悬浮电容电压有效稳定在参考值附近。仿真和实验结果验证了理论分析的正确性及所提控制方法的有效性。

关键词：有源箝位;五电平逆变器;低开关频率;电流谐波最小;优化脉冲模式;悬浮电容电压

DOI：10.15938/j.emc.2019.09.012

中图分类号：TM 341

文献标志码：A

文章编号：1007-449X（2019）09-0092-09

CHMPWM for active neutral point clamped five level converter and flying capacitor voltage control

LI Jie1，XU Yuan2，SONG Wen xiang2

（1.Institute of Technology， Shanghai Open University， Shanghai 200433，China;

2.School of Mechatronic Engineering and Automation， Shanghai University， Shanghai 200444， China）

Abstract：

It is necessary to decrease the switching frequency of the power devices in order to reduce the switching losses of the high capacity inverters. However， it brings about large current harmonics， and special optimized PWM strategies need to be adopted. The current harmonic minimum pulse width modulation （PWM） strategy of five level active neutral point clamped （ANPC） inverter was studied in depth. A computing method of the optimized PWM switching angles based on the genetic algorithm （GA） was proposed. Compared with the traditional Newton iterative method， the proposed method can achieve better current harmonic characteristics. A hysteresis control scheme based on redundant switching states switching was proposed to restrain the fluctuation of the floating capacitor voltage of the five level ANPC inverter. The floating capacitor voltage is effectively stabilized along its reference value by allocating the switching time of the redundant switching states reasonably. Finally， the validity of the theoretical analysis and effectiveness of the proposed control method are verified by simulation and experiments.

Keywords：active neutral point clamped; five level inverter; low switching frequency; current harmonic minimum; optimal pulse pattern; flying capacitor voltage

0引言

多電平逆变器以其输出谐波含量少、功率器件电压应力低等特点在中高电压、大电流、大功率的交流传动场合得到了广泛应用。但是随着电平数的增加，传统二极管箝位式逆变器的中点电压控制会变得更加复杂，H桥级联式逆变器的独立电源数增加，而电容箝位式逆变器存在大量的箝位电容，不仅增大了系统的成本和体积，也增加了系统控制的复杂性。文献提出一种有源中点箝位型的五电平（active neutral point clamped five level，ANPC-5L）逆变器，该结构在ANPC三电平的基础上增加一个飞跨电容模块，与传统拓扑结构相比，中点平衡的控制更简单，输出的电平状态更灵活，可靠性更高。……