FEATURES OF THREE-DIMENSIONAL SIMULATION OF THE ELECTROMAGNETIC FIELDS OF THE ASYNCHRONOUS MOTORS

Abstract

Purpose. Development of new effective approach for the realization of three-dimensional mathematical model of transient electrical and magnetic fields in induction motors, which based on their design features, the nonlinearity of the electrical and magnetic properties of the active and structural materials, which provides adequacy or high simulation accuracy.Research methods. Numerical simulation of the conjugate spatial transient electrical and magnetic fields of the induction motor in the mode of short-circuit, with the help of methods of the theory of electromagnetic fields, finite element, theory of electrical machines and electrical circuits.The obtained results. Theoretical researches and simulation results, which based on numerical realization of the finite element method of three-dimensional mathematical model of the induction motor are obtained. Theoretical researches indicate the features of electrical and magnetic processes of AC power conversion in a short circuit mode. In the area of the coil ends of the low power asynchronous motor it is allocated to 12,5% of the total energy of its magnetic field, which is mainly localized in the active part of the stator, the rotor and the air gap. In the central area of the active part of the induction motor, the length is 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 of its core end. The features of the magnetic field and energy distribution, which have a significant effect on the parameters of a short-circuit of small power induction motor and its operating modes are defined.Scientific novelty. The regularities of the distribution of the induction and magnetic field energy in the short-circuit mode and their quantitative relation for active zone and the area of the coil ends of the stator windings of the low-power asynchronous motors are defined.Practical significance. A new approach for three-dimensional simulation of the electromagnetic process in the induction motor, which consists in differentiating the size of the finite elements and use of approximation functions of Lagrange polynomials based on finite element method are realized. It provides high convergence of numerical realization of short-circuit mode transient processes, reducing the computation time, the requirements for computing resources and high simulation accuracy. Comparison of the energy values of the induction motor magnetic field in short-circuit mode shows, that for Lagrange polynomials approximating the first degree, the relative error do not exceed 3,8% as compared with approximating polynomials of the third degree, while reducing the calculation time in 389 times and requirements for the computational resources – up to 10 times.