基于分子动理论算法的三电平逆变器谐波优化

Optimization of Phase Current Harmonic for Three-level Inverter Based on MMT-OA

在许多大功率交流传动场合下,开关损耗大。为了降低开关损耗,提高逆变器效率,开关频率一般限制在1 kHz以下,导致牵引逆变器中含有大量的谐波。以应用于大功率电力机车的三电平逆变器为特定的研究对象,建立了三电平逆变器最小相电流总谐波畸变率谐波优化模型。采用分子动理论优化算法求解模型时施加了消除窄脉冲算法,完成全调制范围、多种脉波条件下优化函数的求解。与传统SPWM和SHEPWM比较,MMTPWM具有良好的谐波优化效果。最后,通过仿真实验和硬件实验结果验证了理论分析的正确性。

On high-capacity AC drivers,the switching frequency is limited to a certain level,typically below1kHz,in order to reduce switching loss.Due to that,traction inverter output waveforms contain a lot of harmonics.The mathematical model of an optimal pulse width modulation(PWM)method is built,total harmonic distortion(THD)of phase currents is constituted focusing on the three-level inverter used on the high power electric locomotive.The narrow pulse elimination algorithm is applied while using optimization algorithm based on molecalar motion theory MMT-OA to solve the model.The solution of the optimization function on whole modulation range in various pulse wave is completed.MMT-PWM has a good result of harmonic optimization compared with sinusoidal pulse width modulation(SPWM)method and selective harmonic elimination PWM SHEPWM method.All design thoughts and theoretical are verified by emulation and experiment.