We propose a state-feedback controller for switched-reluctance motors as a preliminary step toward the solution of the sensorless control problem (without measurement of rotor variables). We establish global exponential stability. Furthermore, our controller renders the closed-loop system robust to external disturbances, that is, input-to-state stable. Although there exist some works on sensorless control of switched-reluctance motors, these consist mainly of ad hoc solutions without theoretical foundation. The few theoretically validated results in the literature are established under more stringent conditions such as knowledge of the load torque.à corresponds to the phase-inductance variation relative to the rotor angular position, and N r denotes the number of poles.In Equations (1b) and (1c), R represents the stator resistance, J corresponds to the total rotor inertia, and  and ! denote the angular position and velocity, respectively. The inputs are thethen, the map e ! C 1 > J >e 7 ! is passive; the passivity and robustness properties of (23) are conserved.
Proposition 4.2 (GES by state feedback, with load compensation)The system (23) with v D Q C 1 is input-to-state-stable with respect to 1 , and the map 1 7 ! e ! C 1 > J >e is output-strictly passive. Moreover, if 1 Á 0, that is, if v D Q , then the origin .e ; e ! ; Q / D .0; 0; 0/ of (23) is globally exponentially stable for appropriate values of the gains k p , k d , and k i .