Sensorless Control for PMSM with Novel Back EMF Observer Based on Quasi-PR Controller

Sensorless Control of Permanent Magnet Synchronous Motor (PMSM) is a hot research topic nowadays. The main middle and high speed sensorless control methods are based on the back EMF model of the motor. Therefore, the back EMF observer plays an important role in the sensorless control system. The contribution of this paper is to propose a novel back EMF observer based on quasi-PR controller. The proposed quasi-PR observer has a simple structure similar to the sliding mode observer and eliminates the chattering phenomenon at the same time. In this paper, a quasi-PR observer is proposed to estimate the back electromotive forces (BEMFs), and a phase locked loop (PLL) is utilized to estimate the electrical speed and rotor position. The effectiveness is demonstrated by simulation and experimental results.