DC Offset Error Compensation of Current Sensor for Single-phase Permanent Magnet Synchronous Motor Drives

In this paper, a compensation algorithm for DC offset error in the current measurement path of a single-phase permanent magnet synchronous motor (SP-PMSM) is proposed. In general, current information is necessary to perform vector control of the SP-PMSM based on the synchronous reference frame. However, the nonideal nature of the current measurement process causes the DC offset and scaling errors in the current path. Especially, the DC offset error generates a fundamental frequency ripple in the synchronous reference frame dq-axis currents. As a result, the speed ripple of the SP-PMSM drives is the same as the dq-axis current ripples. Therefore, the DC offset error is compensated using an integral controller and detected by the low-pass filter to obtain the dc component in the integral output of stator flux estimator. The effectiveness of the proposed method is verified through several experimental results.