城轨列车牵引逆变器脉宽调制方法研究

Research on Pulse Width Modulation Method of Traction Inverter of Urban Rail Train

城轨列车牵引传动系统开关频率较低,需要根据不同工况分段选择脉宽调制技术。介绍了分段调制技术和指定谐波消除脉宽调制(SHEPWM)技术,针对传统数值方法计算SHEPWM开关角存在的局部收敛、过程复杂等问题,设计了将拟牛顿法和遗传算法结合的混合遗传算法,可以实现全局收敛并减少计算复杂性;对不同载波比SHEPWM的切换过程进行分析,得到谐波电流冲击最小的切换点。使用Matlab/Simulink进行仿真,验证了混合遗传算法的全局收敛性和精确性,并对开关器件输出电流进行快速傅里叶变换(FFT)分析,验证了SHEPWM算法可以有效消除低次谐波。

The switching frequency of electric locomotive traction drive system is low and pulse width modulation technology needs to be selected according to different working conditions.This paper introduced the segmented modulation technology and the specified harmonic elimination pulse wide modulation(SHEPWM)technology,and designs a hybrid genetic algorithm,which effectively realizes the global convergence of the calculation results and reduces the computational complexity;for the synchronization between different modes of the modulation section the switching impact current is analyzed,and the switching point with the smallest harmonic current impact is obtained.Using Matlab/Simulink to do simulation verifies the global convergence and accuracy of the hybrid genetic algorithm,and performs fast Fourier transform(FFT)analysis on the output current of the switching device,which verifies that the SHEPWM algorithm can effectively eliminate low-order harmonics.