Sensorless rotor velocity tracking control of the permanent magnet stepper motor

We present a sensorless rotor velocity tracking controller for the full order, nonlinear dynamic model of the permanent magnet stepper motor actuating a mechanical subsystem. Specifically, the structure of the electrical subsystem dynamics is exploited to reconstruct the rotor position and velocity signals from measurements of stator current and stator voltage. This surrogate rotor position signal is then used to design a control strategy that achieves exponential rotor velocity tracking. Experimental results are included to demonstrate the efficacy of the proposed algorithm.