Estimation of the excitation current and the rotor resistance of an externally excited synchronous machine with an inductively supplied excitation coil

A nonlinear observer for an externally excited synchronous machine (EESM) with an inductively supplied excitation coil is presented, which estimates the excitation current and the rotor resistance. This observer is designed with the direct method of Lyapunov. Using the developed estimation algorithm a precision of over 96 % can be achieved.