Carrier Frequency Component Method for Position Sensorless Control of IPM Motor in Lower Speed Range

Abstract

The Carrier Frequency Component Voltage (CFCV) of a PWM inverter supplying an Interior Permanent Magnet (IPM) motor is used as the rotor position information source. Mathematical expressions relating the rotor position to the CFCV and the corresponding Carrier Frequency Component Current (CFCC) in the motor stator phases are developed. In the lower speed range (up to about 50% of the rated speed) the rotor position has been obtained from the measurement of the CFCC only and has been used to control an IPM motor. The motor speed has been controlled successfully starting from zero speed with excellent performance. Experimental results are presented and discussed. The method is very simple and requires only a few additional electrical components.