A position sensorless control method of interior permanent magnet synchronous motor

This paper presents a simple position sensorless control method of interior permanent magnet synchronous motor. This method cannot be applied basically in the low speed region. However, if the motor speed rapidly reaches the medium or high speed region after starting, it can be used. This method consists of two kinds of position estimation algorithms. At starting, the initial rotor position estimation is carried out, and is based on the variation of the current response caused by the magnetic saturation. In the medium and high speed regions, a mathematical model described by the extended electromotive force (EMF) is introduced. The angle of the extended EMF vector equals the error of the rotor position. The estimation of the extended EMF is based on the principle that the error between the actual current and the estimated current is proportional to that of the extended EMF. Experimental results show the effectiveness of the proposed sensorless control method.