Dynamic and pole-zero analysis of self-excited induction generator using a novel model with iron losses

In this paper, we propose and analyze a novel self-excited induction generator (SEIG) dynamic model with iron losses. The iron losses are represented by means of an equivalent iron loss resistance connected in parallel with the stator inductance. Moreover, the iron loss resistance is modeled as variable with respect to both synchronous frequency and magnetizing flux, whereas the magnetizing flux influence is expressed by means of the corresponding iron loss current. We determined this variation by performing a series of standard no-load tests over a wide range of frequencies and using sinusoidal supply. In order to validate the performance of the proposed model, we carried out a number of simulations and experiments. The results obtained by the proposed model are compared with the results obtained by other commonly used SEIG models, as well as with the results obtained by measurement. All SEIG models were built in the MATLAB/Simulink environment. It is shown that, of all the considered models, the proposed model is the best choice for a comprehensive SEIG analysis because of the high accuracy, high numerical stability and low computational demands. For the same reasons, the proposed model is also a very good candidate for control system design. Finally, the pole-zero maps of two SEIG models and the corresponding pole-zero analysis are given for the first time in this paper.

► Neglecting the iron losses can introduce large errors in the actual SEIG assessment.
► Including the iron losses can lead to a complicated and unstable SEIG model.
► We propose a dynamic SEIG model with iron losses that is both simple and accurate.
► We model the iron losses as variable with respect to both flux and frequency.
► We present and analyze the pole-zero maps of a SEIG.