High-grade position estimation for SRM drives using flux linkage/current correction model

The paper proposes a principle of high resolution sensorless position estimation for a switched reluctance motor (SRM) drive, using either flux linkage or current to correct for errors in rotor position. The estimation algorithm makes full use of the nonlinear magnetic characteristics of the SRM through correlation of current, flux linkage and rotor position. The estimation model is simple, but with no loss in accuracy, leading to few real-time computations. Furthermore, a criterion is proposed to choose the phase most suited for position estimation when more than one phase conducts. The algorithm can also predict flux linkage, which in turn may be used to correct the position estimate further, and the features hereof are discussed. Simulations, real-time implementation and experimental results using the algorithm are presented, and confirm the concept.