Jacek Mikołajewicz

Field-circuit model of the dynamics of electromechanical device supplied by electronic power converters

This paper presents a coupled field‐circuit simulation of transients in a non‐linear electromagnetic device supplied by electronic power converters (inverters, PWM systems). The eddy currents induced in solid cores are considered. The mathematical model of transients includes: equation of electromagnetic field, equations of the electric circuits and equation of motion. Numerical implementation of the algorithm is based on the finite element method. For time‐stepping the Cranck‐Nicholson scheme has been applied.

Reducing power losses in axisymmetric electromechanical converters

Purpose – The aim of the paper is to find the effective methods of power loss reduction in axisymmetric electromagnetic devices and improve their dynamic parameters. As an example the linear tubular motor is considered.Design/methodology/approach – The elaborated algorithm has been applied to analyze the dynamic operation of axisymmetric electromagnetic devices, especially tubular linear induction motors. The mathematical model of transients includes: the equation of electromagnetic field, the equations of electric circuits and the equation of motion. The model is based on the finite element method. For the time‐stepping, the Cranck‐Nicholson scheme is applied. In order to include non‐linearity, the Newton‐Raphson process is adopted.Findings – In order to reduce the influence of eddy currents, it is suggested that the solid core should be equipped with one or several radial slots. In such a case, the radial component of eddy currents occurs near the slot and disturbs the axial symmetry of the system. Howe...

Model of dynamic operation of stepper linear reluctance motor based on field approach

Purpose – The aim of this paper is to analyse the influence of various methods of controlling a stepper linear reluctance motor on the dynamic parameters of this motor.Design/methodology/approach – Construction, principle of working, and mathematical model of a four‐band stepper linear reluctance motor are shortly discussed. In order to elaborate an effective tool for motor performance analysis, a circuital approach was applied. To increase model accuracy, major parameters of the model (main self‐ and leakage inductances) were calculated on the basis of a 3D electromagnetic field distribution using Finite Element Method (FEM). The nonlinearity of the core was taken into account. Elaborated mathematical model was implemented in MatLab‐Simulink environment. Selected results of investigations are presented.Findings – The elaborated mathematical model and the review of control methods are very useful for analysis of dynamic operation of stepper linear reluctance motors.Originality/value – The paper provides a...