Sensorless Control and On-Line Estimation of Inductances of IPMSMs Using Current Derivatives

Abstract

This paper presents a sensorless control method and a very fast on-line estimation method of inductances of an IPMSM. The current derivatives at one active- voltage vector and one zero-voltage vector are measured every PWM cycle to estimate the rotor speed and position with the aim of increasing the estimation accuracy and reducing total harmonic distortion. In addition, machine inductances can be estimated on-line based on these current derivatives and the DC bus voltage of the inverter. The proposed on-line parameter identification method can overcome the drawback of the existing off-line methods, namely the requirement of a robust mechanical clamping system and test signal generators. The proposed on-line method also addresses the limit of the existing on-line methods, such as slow update and the possibility of incorrect convergence of the estimated parameters. Extensive experimental studies were conducted to verify the effectiveness and robustness of the proposed sensorless control and parameter identification of the IPMSM.