Research On Charaeteristies Of Transformer By Preisach Model And Fixed-point Harmonic Balance Method

The Preisach model is one of important hysteresis models which are used to study the magnetic properties of the ferromagnetic materials. The Preisach model is based on the hysteresis operator which can reflect characteristics of microscopic particles, and it has intuitive geometric significance and is easy to identify model parameters by numerical method. In this paper, according to the basic theory of the classical Preisach model and characteristics of the ferromagnetic material,the method to fit the hysteresis loop of ferromagnetic materials is studied deeply. First, the assumption that the Preisach distribution function’s variables can be separated is made, and then a new Preisach model which is based on the limiting hysteresis loop is developed; Second, the congruence properties of the Preisach models is taken into consideration, a new Preisach model which is based on the first-order reversal curves(FORC) is derived by referring to the Everett function definition expression. The above two models are used to simulate the transformer core’s magnetization curve, then the calculated results are compared with the experimental data, and they are coincided well. Third, the fixed point harmonic balance equations of a single-phase three-limb transformer are obtained by using the fixed point harmonic balance method, and then the simulations are carried out to calculate the winding excitation current and the magnetic flux in the central core. The results obtained from simulations and experimental measurements are compared, which verifies the accuracy and validity of the proposed method.