Estimation of pole position of an inverter fed permanent-magnet synchronous machine by the extended Kalman filter

It is necessary to know exactly the pole position and the speed of a synchronous motor controlled by the field oriented concept. It is a common practice to measure these variables using conventional electro-mechanical devices such as angle encoder and tachogenerator. This makes the drive to become bulky and expensive and has considerable measurement errors. To overcome these disadvantages the pole position as well as the motor speed of a permanent-magnet synchronous motor (PMSM) can be estimated by measuring motor´s currents and voltages. Since there are modeling and measurement errors, extended Kalman filter (EM7) algorithm used in this paper to minimize these errors. Finally discussion of problems encountered during modeling along with the results of the simulation are presented