The proposal of low speed sensorless drives by symmetrical carrier PWM

The rotor position sensor is required to control Permanent Magnet Synchronous Motor (PMSM). However, the rotor position sensor, for example, Resolvers or Pulse Generator (PG) have some disadvantages which are an increase of total volume of the motor, fault of power supply lines and signal lines of these sensors, and maintenance. To overcome these difficulties, sensorless control methods have been developed. From standstill, sensorless drive method for saliency PMSMs has been already proposed [1]-[5]. However, audible noise occurs by supply. In this paper, we achieve sensorless drive for PMSM using the PWM generation method which used three symmetrical carriers. We verify that proposed method has low audible noise and a high response.