Wide-Bandwidth Estimation of Cross-Coupling Factors for Advanced Position-Sensorless Control of IPMSM

This paper presents a wide-bandwidth estimation method of cross-coupling factors in the dq-axis inductance for current control and position estimation in advanced position-sensorless control of interior permanent magnet synchronous motors (IPMSMs). The cross-coupling factors from the complex magnetic passes depend on the rotor position and current. These cross-coupling factors reduce robustness and position estimation accuracy in position-sensorless control methods with the d-axis high-frequency voltage injection. Since estimation errors in each estimation period change the current from the voltage injection, the cross-coupling factors vary in the high-frequency bandwidth around the voltage injection frequency. Consequently, the estimated position has errors from the static magnetic characteristics in the low-frequency bandwidth and vibration in the high-frequency bandwidth. The proposed method integrates two estimated cross-coupling factors with different frequency bandwidths. The estimated values are derived from the current variation from the injected voltage and the estimated position. Experimental results show a reduction in position estimation error, smaller vibration during rotation, and improved robustness to disturbance.