Sensorless field oriented speed control of a hybrid and a permanent magnet disk stepper motor using an extended Kalman filter

For the sensorless speed control of stepper motors, the rotor position and the speed can be determined by an extended Kalman filter which estimates the state variables by only measuring the phase voltages and currents. Experimental results confirm that these robust, four-quadrant, sensorless drives cover a wide range of speed nearly down to standstill