Aiming at the problem that the switching frequency is low and the switching state is changed slowly,the control period is not synchronized with the modulation period,a locomotive modulation method is proposed to improve the dynamic performance of the electric locomotive.The method is based on selective harmonic elimination pulse width modulation (SHEPWM),the angle dynamic updating process is optimized and combined with the multimode SHEPWM modulation strategy in different modes.In the process of switching angle updating,the method of linear interpolation and curve fitting is adopted to obtain a more accurate switching angle to ensure the superior capability of harmonics elimination,the method has been able to improve the dynamic performance of the converter,the controller bandwidth is not affected.Finally,the mode is made by Matlab/Simulink,and the method is carried out on the low power platform.The simulation and experimental results show that the proposed method can eliminate the low harmonics and can not effect the controller bandwidth.It can be used as a locomotive traction converter modulation method.%针对电力机车牵引变换器在调制方法下开关频率较低时更新慢、控制周期与调制周期不同步的问题,提出一种提高电力机车动态性能的机车调制方法.该方法以特定谐波消除脉宽调制(SHEPWM)为基础,对开关角度动态更新过程进行优化,并结合不同模式下的SHEPWM策略进行实施.在开关角度更新过程中采用线性插值和曲线拟合的方法获取较准确的开关角度,以保证其优越的消除谐波能力,同时将多模式下的SHEPWM相互结合,发挥其多个模式各自的优点,得到了一种能够提高变换器动态性能、控制器带宽不受影响的机车调制方法.最后在Matlab/Simulink下建立了机车牵引系统模型,并用所提方法进行了仿真,在小功率平台上对所提方法进行了实验验证.仿真和实验结果均表明,所提方法在消除低次谐波的同时,不影响控制器带宽,可作为机车牵引变换器的调制方法.
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