FEATURES OF PARAMETER DETERMINATION OF THE INDUCTION MOTOR SUBSTITUTION CIRCUIT FOR SHORT-CIRCUIT MODE

Abstract

Purpose. Development of a new method for determining the parameters of an induction motor, based on a three-dimensional transient mathematical model of the electrical and magnetic fields, that provides high accuracy and reliability of results and considering the design features of induction motors, nonlinearity of the electrophysical and magnetic properties of active and structural materials. Methods. Numerical simulation of the conjugate spatial transient electrical and magnetic fields of the induction motor in the short-circuit mode, with help methods of the theory of electromagnetic fields, finite element, theory of electrical machines and electrical circuits. Results. Theoretical researches and simulation results, which based on numerical realization of the finite element method of three-dimensional transient mathematical model of the electrical and magnetic fields in induction motor which displayed the features of the processes of AC energy conversion in the experimental short-circuit mode are obtained. The magnetic field energy is localized mainly in the area of the cores and slots of the stator and rotor of the low-power induction motors by researches was determined. In the zone of the frontal parts of the stator windings, up to 15% of the magnetic field energy of the induction motor is evolved. In the central area of the active part of the induction motor, a length up to 60% of the total length of the stator and rotor core, the magnetic field has plane-parallel form, but is transformed into zones of coil ends of the stator windings and near its end of the core. The influence of the characteristic features of the magnetic field distribution, its energy on the substitution circuit parameters of the low power induction motor and its operating modes are defined. The ratios between the resistances inductive coil ends zone of the stator windings and slots zone stator and rotor windings for an induction motor in short-circuit mode were respectively 14.7% and 85.3%. Originality. The regularities of the spatial distribution of induction and the energy of the magnetic field in the experimental short-circuit mode are defined. When the localization of the magnetic field energy in the frontal parts zone of the stator windings and in the cores and slots regions of the stator and rotor of low-power induction motors, the quantitative relations between the inductive resistances are determined. Practical value. Through the implementation of the dynamic spatial model of electromagnetic fields by the finite element method and numerical simulation data of the short-circuit dynamic mode of the induction motor, the parameters taking into account the structural features of the stator and rotor, and the nonlinear properties of active materials in the multicomponent modeling domain of its substitution circuit are determined. It is proved, that the new approach to the determination of the substitution circuit parameters of induction motors based on simulation data field provides a significant increase in accuracy compared to conventional iterative-empirical methods.