Discrete time sliding mode observer for automotive alternator

This paper concerns with theoretical development of a sliding mode observer for the automotive alternator with time varying amplitude and frequency. Preliminary estimation of the back electromotive force is based on a sliding mode observer and, then, a time varying asymptotic observer is developed for estimating the back electromotive force with a crude measurement of the engine speed. The design of the observer with respect to battery current measurement is studied for an easier and less expensive implementation. Convergence analysis for different cases of the desired state estimators are presented. The discrete-time version of the aforementioned observer is developed and simulation results are presented for validation of the proposed observation algorithms.