A Novel Current Measurement Error Correction Method for PMSM Based on Phase Current Harmonic Analysis

Current measurement error (CME) could lead to large torque ripple, increased losses, and reduced control performance. The long-term operation under heavy load of magnetic levitation turbo molecular pumps (MLTMPs) makes their core component–the permanent magnet synchronous motor (PMSM)–particularly susceptible to CME, thereby reducing ultrahigh vacuum performance. This article introduces a novel method for correcting CME in PMSMs by analyzing phase current harmonics, which addresses the issue of traditional methods ignoring phase current distortion. First, a control model under the CME conditions is proposed, utilizing a Proportional Integral Resonant controller to mitigate periodic disturbances. Second, the quantitative relationship between the CME and phase currents is derived through harmonic analysis based on the proposed control model. Then, an improved synchronous frequency extractor is employed for the extraction and compensation of the CME. This method features ease of application, independence from motor parameters, and good real-time performance. Finally, experiments on MLTMPs validate the effectiveness of the proposed approach.