Position Sensorless Control of Interior Permanent Magnet Synchronous Motor Using Extended Electromotive Force

Abstract

Drive of permanent magnet synchronous motor (PMSM) requires the rotor position information to control the motor torque, and they are generally detected by mechanical position sensor such as an encoder or a resolver. However, these sensors increase the machine size and the cost of drive, and reduce reliability of the system. Therefore, many papers about position sensorless drive method of PMSM have been published. This paper presents a position sensorless control of interior permanent magnet synchronous motor (IPMSM). A mathematical model of IPMSM using an extended electromotive force (EMF) in the rotating reference frame is utilized to estimate the rotor speed and position. This model has a simple structure integrating position information into an extended EMF term. Therefore, the sensorless control based on the mathematical motor model can be simply implemented. The estimation method proposed is based on the principle that the error of the current is proportional to that of extended EMF. This method was carried out using a 6-pole, 400W, 1750r/min test motor system. As a result, the sensorless speed control was achieved from 80r/min to 1800r/min under 0-100% loads.