A more accurate permanent magnet synchronous motor model by taking parameter variations and loss components into account for sensorless control applications

Development of sensorless control schemes for permanent magnet synchronous machines and related topics of machine parameter estimation have received much attention during the last few years. Most of the sensorless schemes are based on the measurements of motor currents, voltages, and motor parameters. Subsequently the accuracy of such methods greatly depends on the availability of an accurate circuit model for the motor. This paper presents a detailed analytical method to obtain an accurate synchronous reference frame motor model by taking loss components and parameter variations into account. Also, a method for on-line parameter identification to improve the model, test schemes to measure the equivalent circuit parameters and to calculate constants that govern the parameter variations, are discussed.