Grzegorz Utrata

Spectral inductance of the linear motor‐space harmonic analysis

Purpose – The aim of the paper is to present the methodology of obtaining an approximate equivalent circuit composed of lumped parameters which describes an electromagnetic state of induction machines (IMs) with solid secondary. Higher space harmonic field components are taken into account. The proposed method of machine model constructing is useful for solving electrodynamics states of solid secondary IMs, as well linear machines.Design/methodology/approach – A determination of equivalent circuit parameters of a polyharmonic machine is divided into two steps. In the first step, frequency plots of the spectral inductances are derived – for each of the space harmonic components – from an electromagnetic field distribution calculated by means of the finite element method. In the second step, each of the spectral inductances are represented by the operational inductances which corresponds to the equivalent circuit composed of parallel connected the magnetizing inductance and branches consisting of resistance...

Estimation of electromagnetic parameters of an induction motor multi-loop equivalent circuit based on the machine inductance frequency characteristic

The variability of electromagnetic parameters of induction motors with deep-bar cage or solid rotors is represented, with a satisfactory approximation, by the machine secondary multi-loop equivalent circuit with constant lumped parameters. An estimation procedure of electromagnetic parameters of such an equivalent circuit is presented in the paper. The procedure is carried out using the measured frequency characteristic determined on the basis of instantaneous values of investigated induction motor electromechanical quantities. The study has been subjected to an induction motor with a solid rotor manufactured from the magnetic material, i.e. a machine characterized by a significant skin effect occurring in rotor solid conductive elements.

Induction motor electromechanical quantities estimation based on the inductance frequency characteristic — Simulation studies

The estimation methodology of electromechanical quantities of an induction motor has been presented in the paper. The investigated estimation algorithms are based on the motor inductance frequency characteristic and the machine secondary multi-loop equivalent circuit, reproducing this characteristic in the analyzed frequency range. The conducted simulation studies indicate the possibility of using the proposed algorithms in an estimation process of considered electromechanical quantities of an induction motor.

A methodology for electromagnetic parameter estimation of an induction motor equivalent circuit based on the load curve test

The paper presents the methodology for electromagnetic parameter estimation of the considered equivalent circuits of induction machines, enabling the more effective usage of information obtained as a result of realisation of the measuring procedure “Load curve test” described in the standard PN-EN 60034-28: 2013. An evaluation of adequacy of electromagnetic parameters estimated in accordance with the aforementioned standard and the presented methodology has been performed on the basis of the comparison of impedance frequency characteristics of the tested induction motor derived from measurement with the corresponding characteristics calculated by means of motor mathematical models resulted from the studied equivalent circuits with estimated parameters. Additional verification of correctness of estimated electromagnetic parameters has been realized by confronting the steady-state power factor-speed, stator current-speed and torque-speed characteristics of the tested induction motor determined experimentally and through the machine operation simulations carried out with the use of the considered equivalent circuits.

Angular velocity estimator based on the inductance frequency characteristic for an inverter fed induction motor — Simulation studies

The selected simulation results of the angular velocity estimator, whose operation algorithm has been elaborated basing on the inductance frequency characteristic of the considered induction motor (IM), have been presented in the paper. The simulations have been conducted at specified operating frequencies of the scalar-controlled induction motor drive with a modulator employing the space vector pulse width modulation technique. This allowed for the indication of the influence of the IM current distortion on the accuracy of the IM angular velocity estimation process and thereby the efficiency of the considered IM drive. The impact of the estimator input signals filtering on the level of angular velocity estimation and tracking errors has been also investigated in the paper. The analysis has been conducted for the mathematical model of the four-pole induction motor of Sg 132S-4 type with a solid rotor manufactured from the magnetic material S235JR.