Sensorless control of permanent magnet motor with a simple position controller targeted for low-performance MCUs

The paper presents a control strategy of the non-salient permanent magnet motor without a position sensor, which is targeted for low-performance MCUs. The presented control strategy is based on a closed-loop control of the phase-shift between motor voltage and currents. The control algorithm adaptively changes the phase-shift based on an actual motor operating conditions, keeping an angle between rotor magnetic flux and stator current at 90 degrees. The targeting applications are high-volume, low-power and cost-sensitive consumer products, where sensored or sensorless brush-less DC motors are used.