Unity power factor control for PMSM position sensorless drive

A method of sensorless vector control with unity power factor for surface mounted permanent magnet synchronous motor (SPMSM) is presented. The method can realize the motor control of unity power factor under the rated speed, and the motor can also work normally under high speed by way of field weakening. Comparing with the vector control of the statorpsilas magnetic force plumbs with the permanent magnet rotorpsilas magnetic force, this method has advantage of needing no parameters of the motor, thus the control system is simple and reliable. Moreover, the method can approximatively realize the control of the invariable stator magnetic linkage with no problem of saturated magnetic path, and enters into the control area of field weakening. The structure and parameters of the experiment system are introduced. The experimental results are given, and the results show the rightness of the theoretic analysis.