COMPUTATION OF NON-LINEAR CHARACTERISTICS FOR WINDINGS OF SATURATED INDUCTION SLIP RING MOTOR

Abstract

Analytical expressions of relationships between linked fluxes and currents of all individual windings are very important in modelling of electrical machines with saturated magnetic circuit. For induction machines the model can operate by magnetising current of the first and the higher harmonics instead of the circuit currents. In the paper the first and the third harmonics are taken into account. The non-linear characteristics based on the co-energy function were approximated by power series and transformed to the symmetrical components. The general properties of the co-energy function for a cylindrical machine were formulated and used in calculations of the linked fluxes by FEM method. The terms of the simplest series were calculated from the magnetic field computed for a slip ring induction motor. As a result, the particular terms of the series were determined, and the saturation effects generated by the positive and zero symmetrical components of the currents were described.