Current Measurement Offset Error Compensation Based on Extended State Observer for PMSM Drive Systems

Offset error from the measured phase current mostly causes a performance afflicted for permanent-magnet synchronous motor (PMSM) drives, and innovative solutions are eagerly sought. Considering this, this article proposes an extended state observer (ESO) to compensate the current measurement offset error (CMOE) without additional hardware. In the proposed scheme, the ESO is designed in a stationary coordinate system to estimate CMOE in dc form. Notably, the proposed ESO possesses a second-order low-pass filtering characteristics. With this, the proposed method shows a high robustness against the disturbances from the ac components caused by motor parameters changes, etc. The feasibility of the proposed scheme for CMOE is thoroughly verified by extensive experimental tests based on the test bench of 0.75-kW PMSM drives.