低开关频率选择谐波消除调制的母线波动补偿

DC-link voltage fluctuation compensation for selected harmonics elimination under low switching frequency

提出基于选择谐波消除脉宽调制(SHEPWM)的补偿策略,用于抑制由直流母线电压波动引起的列车牵引电机电流与转矩波动.根据每一基波周期内的调制脉冲数确定同步处理区间,使用重复预测器对下一处理区间内的直流母线电压波形进行预测.根据预测的母线电压波形与开关时刻估计下一处理区间内的磁链误差,并相应地调整开关时刻以消除磁链误差.在18 kW永磁体内置式永磁同步电动机(IPMSM)上分别对采用完整的补偿策略、采用近似的处理区间内平均母线电压补偿策略与不采用任何补偿策略的情况进行实验.结果表明提出的补偿策略能显著降低由直流母线电压波动所引起的低次电流谐波和电机转矩波动,且相比近似的处理区间内平均母线电压补偿策略具有更好的电流与转矩波动抑制效果.

A novel compensation strategy for selected harmonics elimination pulse width modulation(SHEPWM)was proposed to suppress the current and torque ripple of railway traction motor caused by DC-link voltage fluctuation.Synchronous processing sections were decided according to the number of pulse per fundamental cycle of the modulation.A repetitive predictor was employed to predict the DC-link voltage pattern in the next section.Flux error of the next section was then estimated and the switching instants in the section were accordingly adjusted to compensate the flux error.Experiments were run on an 18 kW traction interior-mounted permanent magnet synchronous motor(IPMSM)with the proposed compensation strategy,with the average DC-link voltage compensation and without any compensation.Results showed that the proposed strategy can significantly eliminate the low-order harmonic current components and motor torque ripple caused by the DC-link voltage fluctuation,and was more effective than average DC-link voltage compensation.