Sensorless Control of PMSM and BDCM Based On EMF Extraction And Extended Kalman Estimator

Abstract

In this two-part paper, a powerful and accurate method for sensorless control of permanent magnet brushless motors is explained. The method doesn't include any modification to the classical construction of such motors and can be easily integrated within the drive electronics. It is applicable to both motor types, i.e. those with sinusoidal or trapezoidal back EMF. The method is independent of excitation current profile. It is also virtually independent of system parameters. The back EMF waveform is extracted online using simple and integration-free algebraic expression through a newly proposed measurement setup. It is then used within the corrective phase of an extended Kalman filter (EKF). The method functionality is tested by simulation for both motor types and for different excitation current profiles. Simulation results show a good performance at very low speed. This part introduces the topics common to both motor types and presents in detail the application of the proposed method to the case of sinusoidal back EMF machine.