Adapted Back-EMF Sensorless Control for Permanent Magnet Synchronous Motors

Abstract

This paper presents a sensorless control method for permanent magnet synchronous motors (PMSMs) based on the reconstruction of the speed and position of the rotor using the traditional method of the back-EMF with the addition of an innovative observation speed. The gains of the observer are a function of the speed and here a simple adaptation law that avoids the calculation in real time of the gains is proposed. Furthermore the speed is calculated from the back-EMF which induces a velocity oscillation due to the observation errors inherent to the sinusoidal forms. To overcome this difficulty, the direct derivation of the position is proposed taking into account the discontinuity of the position due to the modulo function. Simulation and experimental results validate the proposed method.

Hybrid sensorless control of PMSM in full speed range using HFI and back-EMF

“…Due to the problem at zero speed estimation for these methods which is based on the model-based techniques of the machine, the fundamental component model technique relies on the position and velocity dependency of the backelectromotive-force (back-EMF) [10] of the motor. These techniques present a general problem at standstill, the back electromotive force [10][11], is zero amplitude when the machine rotates at low speed, so we cannot distinguish between the real component of the back-EMF and noise signal.…”

“…The performance of the back-EMF based sensorless vector control is mainly determined by the sensorless algorithms with respect to the position and speed estimation. Recently, the back-EMF based methods are only intended to be operated in medium to high speed range [11]. In the low speed region as the back-EMF is reduced, the influence of parameter variations and measurement noise become more important.…”