Analytical Approach for Position Observation Error Correction in IPMSM Sensorless Drives Using Online Multiparameter Estimation

Accurate position observation in interior permanent magnet synchronous motors (IPMSMs) model-based sensorless drive relies on the precision of model parameters. This article first derives an analytical function that quantitatively relates position observation error to mismatches in multiple model parameters and the current lead angle in one unified equation. The position error mechanism highlights the potential limitations of relying solely on steady-state-based parameter estimation. It also emphasizes the importance of introducing current transient states for online multiparameter estimation. To reduce the position observation error caused by parameter mismatch, a multiparameter estimation method with extra small signal injection based on the dual extended Kalman filter with a position error prior prediction structure is proposed for the IPMSM sensorless drive. The method is built upon the misaligned synchronous frame model where the asymmetry in dq-axis magnetic path, flux coupling terms, and position observation error are well considered. This makes the proposed method effective for both steady and transient states within the rated speed. Additional experiments corroborate both the validity of the analysis and the effectiveness of the proposed technique.