Rotor position detection techniques for brushless permanent-magnet and reluctance motor drives

The basic principles of sensorless rotor position detection in brushless permanent magnet and reluctance motor drives are discussed. Techniques for sensorless rotor position detection from the literature are reviewed. All the methods proposed in the literature extract the rotor position information from measurements on the phase winding circuits. Such techniques therefore eliminate the connections of the sensor to the motor and controller, simplifying the system construction. Furthermore, continuous rotor position information can be obtained for optimal control.<>