基于改进相电流重构的电流采样校正方法

永磁同步电机的相电流采样中常包含直流偏置和幅值不等的误差,导致转矩和转速中出现波动。通常采用的相电流直接采样的方法无法对幅值和零漂误差进行辨识和消除。针对该问题,采用相电流重构与零漂在线估计相结合的方法来获得准确的三相电流。首先,改变电流传感器的安装位置,测得零电压矢量作用时段的电流续流值,实现三相电流的重构。重构之后,有一相电流中不含直流偏置,从而可以用于获得准确的电流过零点,进而完成电流传感器零漂的在线估计。所提的方法能够在不增加硬件成本的情况下消除电流采样中的误差。实验结果表明,该方法能够有效地提高电流采样精度,降低转速波动。

Current Sampling Correction Method Based on Improved Phase Current Reconstruction

Phase current sampling of permanent magnet synchronous motor often includes DC offset and amplitude unequal errors,resulting in fluctuations in torque and speed. The commonly used phase current direct sampling method cannot identify and eliminate amplitude and zero drift errors. To solve this problem,the combination of phase current reconstruction and zero drift online estimation was used to obtain accurate three-phase current. Firstly,the installation position of the current sensor was changed,and the current freewheeling value of the zero-voltage vector action period was measured to realize the reconstruction of the three-phase current.After reconstruction,there was no DC bias in one phase current,which could be used to obtain accurate current zero-crossing point,thus the online estimation of zero drift of current sensor was accomplised. The method proposed can eliminate errors in current sampling without increasing hardware costs. The experimental results show that the method can effectively improve the current sampling accuracy and reduce the speed fluctuation.