Wojciech Szelag

Finite element analysis of transient electromagnetic‐thermal phenomena in a squirrel cage motor

Purpose – The purpose of this paper is to elaborate the method and algorithm for the analysis of electromagnetic and thermal transients in a squirrel cage induction motor.Design/methodology/approach – The paper presents the special software for transient finite element (FE) analysis of coupled electromagnetic‐thermal problems in a squirrel cage induction motor. The software has been prepared and is successfully applied in the design of special squirrel cage motors, e.g. the motors working in cryogenic conditions. A time‐stepping FE method and transients analysis of an induction motor has been applied. The nonlinearity of the magnetic circuit, the movement of the rotor and the skewed slots have been taken into account. The results of computations have been compared with measurements.Findings – The method presented and the elaborated specialised software for FE analysis of electromagnetic and thermal transients are used to determine the dynamic performance of the squirrel‐cage induction motor. The results o...

Multiphase permanent magnet synchronous motors with fractional slot windings

Purpose The purpose of this paper is to investigate advantages of multiphase permanent magnet synchronous motors (PMSM) with fractional slot concentrated windings (FSCW). The investigation is based on comparative analysis and assessment of FSCW PMSM wound as 3, 6, 9 and 12 phase machines suited for low speed applications. Design/methodology/approach The investigations are focussed on distortions of back electromotive (emf) and magnetomotive force (mmf) with the torque ripples and motors’ performance taken into account. The finite element models with the aid of customized computer code have been adopted for motor winding design and back emf, mmf and motor performance analyses. Findings The novel multiphase winding layouts were found to offer lower content of sub-harmonics in the mmf waveforms compared with the traditional three-phase machine designs. Moreover, the investigated multiphase machines exhibited higher average value of the electromagnetic torque, while the multiphase PMSM machines with FSCW were further characterized by significantly lower torque pulsations. Originality/value The analyses presented in this paper demonstrate that PMSM with FSCW are advantageous to their counterpart three-phase machines. Specifically, they offer higher performance and are more suitable to work with multiple drives supplying segmented winding system. This ability of using multi-drive supply for one motor offers flexibility and cost reduction while increasing fault tolerant power train system.

FE analysis of magnetorheological brake with hybrid excitation

The paper deals with coupled electromagnetic, hydrodynamic, thermal and mechanical motion phenomena in a magnetorheological fluid brake with hybrid excitation. A numerical model of these phenomena is presented. Elaborated algorithm and software have been used to analyse the steady state and transients in the MR brake with hybrid excitation. Chosen results of calculation and measurements have been presented.

Influence of temperature on partial demagnetization of the permanent magnets during starting process of line start permanent magnet synchronous motor

The paper presents a 2D field-circuit model of coupled electromagnetic thermal and mechanical phenomena in a line start permanent magnet synchronous motor (LSPMSM). The nonlinearity of the magnetic circuit, the influence of temperature on magnetic properties of the permanent magnets as well as on electric and thermal properties of the materials have been taken into account. The elaborated on the basis of this model algorithm as well as a developed computer program have been used to analyze the influence of temperature and armature reaction on the magnet stabilization during the starting process of the considered motor. The selected results of simulations have been presented and discussed.

Description of Multiply Connected Regions with Induced Currents Using T - T 0 Method

The paper presents the description of multiply connected conducting regions (MCCR) in the flnite elements space. In order to deflne induced currents distribution in multiply connected regions, an innovative method of combined vector potentials T and T0 has been suggested. The equations of T-T0 method have been presented. The relations describing sources for the fleld of induced currents in the discussed regions have been given. The proposed method has been applied to solve Problem No. 7 of the International TEAM Workshops. The selected results of calculation have been compared with the measurement results.

Simulation and investigation of magnetorheological fluid brake

The paper deals with coupled electromagnetic, hydrodynamic and mechanical motion phenomena in magnetorheological fluid (or simply MRF) brakes. The governing equations of these phenomena are presented. The numerical implementation of the mathematical model is based on the finite element method. Elaborated computer program is used to simulate the operation of MRF brake prototype. In order to verify elaborated algorithm and program, the investigation of the prototype of MR brake is carried out. The dynamic properties as well as mechanical and control characteristics of the brake are determined. The influence of MR fluid properties on functional parameters of the brake is also considered. Chosen results of simulations and measurements are presented.

Analysis of the multi-drive powered permanent magnet synchronous motor under drive fault conditions

The paper deals with analysis of operation under fault conditions of the permanent magnet synchronous motor (PMSM) supply systems composed of a number of 3-phase drives. The considered 3 test PMSM differ in number of phases of supply system and arrangement of the windings. The elaborated field models of these motors have been used to determine the electromagnetic torque and unbalanced magnetic pull force waveforms under the drive fault conditions. The selected results of simulations have been presented and discussed.

Influence of magnet and cage shape on properties of the line start synchronous motor with powder hybrid rotor

The new structure of the line start synchronous motor with the arc bonded magnets placed inside the rotor and the magnetic circuit made of the Somaloy 500 powder material has been presented. In order to obtain line start ability a squirrel-cage was placed in the rotor. The field-circuit model of the considered motor has been elaborated in the Maxwell environment. To perform analysis in the elaborated model the geometries of the squirrel-cage bars and magnets have been parameterized. A sensitivity analysis of magnet and bar shapes has been carried out. Particular attention was paid to the dimensions of the magnet, which have the greatest impact on functional parameters of the motor in the steady state operation. The selected simulation results of starting up and steady state operation have been presented.

Analysis of electromagnetic phenomena in the two-winding permanent magnet synchronous generator

The paper deals with the analysis of electromagnetic phenomena in a two-winding permanent magnet synchronous generator (PMSG) driven by wind turbines. The machines winding is designed to facilitate application of a low cost and reliable AC/DC power electronic converter. The finite element method has been employed to develop numerical models for the case study problem of the machines. Special attention was paid to the comparison of torque waveforms and core losses in the proposed and reference, sinusoidal loaded machine with a typical design of a winding.