Intermittent carrier frequency component method (ICFCM) for IPM motor rotor position sensorless control

In this paper utilization of MMF rotating at the switching frequency of a naturally sampled voltage source inverter as rotor position information source for IPM motor sensorless control is presented. The rotating MMF is created by periodically phase shifting the switching frequency component voltage in the three phases by 120 degrees. Controlling the phase shifting period, loss due to the high frequency rotating MMF can be controlled. The method is very easy to implement and doesn't require any additional sensing hardware. Since switching frequency of PWM inverters are generally high there is no torque ripple problem, and the acoustic noise level is low. Experimental results demonstrating the effectiveness of this method in low-speed range has been presented and discussed.