Overview of Sensorless Control of Permanent Magnet Syncoronous Motors

To achieve sensorless control of permanent magnet synchronous motors(PMSM),information on the rotor speed is extracted from measured stator currents and from voltages at motor terminals.Traditional mechanical position sensor is replaced,and this results in a low cost and high reliable system.Open-loop estimators or closed-loop observers are used for motor position estimation.By exploiting the non-ideal property of motor to acquire position information,sensorless control is extended to low speed range even including zero.A review of the literature addressing PMSM sensorless control was provided.The advantages and disadvantages of different sensorless methods were discussed in details.