Position and speed estimation of a switched reluctance motor

Abstract

This paper deals with the design of an observer for the estimation of rotor position and velocity for switched reluctance motors (SRMs). We present a reduced order, non-linear observer, driven by stator currents and voltages. We derive sufficient conditions for the observer convergence, that lead to a design procedure. An extended observer is also presented that handles an unknown load torque or slow load torque variations. Closed loop operation of the observer and the motor is shown to converge exponentially. Performance is illustrated with simulations that show very good behaviour, even when there are uncertainties in the model parameters and in the flux model.