差分进化算法用于带辅助臂的NPC逆变器 PWM调制

摘要

为降低三相高压变频系统的总谐波畸变率，采用带辅助臂的中性点钳位型NPC逆变器。该逆变器在三电平NPC逆变器基础上，仅增加了少量的器件，可实现五电平相电压。针对该逆变器输出电平不完全独立的特点，提出一种脉冲宽度调制方法。分析了三相变频系统中Us，Eg，Er的谐波。分别在恒Us/ω、恒Eg/ω、恒Er/ω控制的情况下，采用差分进化算法对逆变器开关时刻进行优化，获得了较好的谐波优化结果。%To reduce the total harmonic distortion of three-phase high-voltage frequency-conversion system , neutral point clamped inverter with auxiliary arm is applied .This inverter can export five-level phase voltage while only small quantities of elements are added .A sort of pulse width modulation is put forward for this inverter in which output voltages are not absolutely independent .The harmonics of Us , Eg , Er in three-phase frequency-conversion system are analyzed .Differential evolution algorithm is ap-plied to switch times optimization in this inverter while Us/ω, Eg/ω, Er/ωare constant respectively .The results show that harmonics are well limited .