Estimation of a Global Synchronous Machine Model Using a Multiple-Input Multiple-Output Estimator

In this paper the measurement results of a series of standstill frequency response (SSFR) tests, performed at different magnetization levels, are discussed. For each data set an individual d-axis model is estimated, which allows the variation of the different parameters to be seen as a function of saturation. A global estimator is presented that uses the different data sets to estimate one global model, including the field-toarmature turns ratio. The global estimator is based on an impedance matrix representation of the synchronous machine. This global estimator assumes that only the d-axis main inductance is saturation dependent. The individual estimated models justify this assumption. Finally, the relative additional error of the global estimated d-axis equivalent circuit with the individual estimated ones is studied. The measurement results discussed in this paper are obtained on a four-pole 130 kVA synchronous machine.