Mariusz Jagiela

Design of High-Speed Hybrid Hysteresis Motor Rotor Using Finite Element Model and Decision Process

This paper aims at designing a high-speed hysteresis motor rotor with permanent magnets embedded in the magnetic system. The considered motor, due to the rotational magnetization and considerable impact of harmonic losses in the rotor, is an electrical machine whose design requires the involvement of a field model. A multicriteria design procedure consisting of a computer experiment, employing time-stepping finite element and vector hysteresis models and a search for the feasible design using the analytic hierarchy process, is conducted. The feasible design is found uniquely and a prototype motor is constructed and verifyingly tested.

Modeling dynamic end effects in rotary armature of rotary-linear induction motor

The performance of twin-armature rotary-linear induction motor is presented in this paper. The stator consists of a rotary armature and linear armature placed aside one another. Both armatures have a common rotor which consists of solid iron cylinder covered with a thin copper layer. The rotor can move rotary, linearly or with helical motion. The linear motion generates dynamic end effect on both linear and rotary armature. Modeling such an effect in rotary armature is a significant challenge as it requires a solution considering motion with two degrees of mechanical freedom. The approach used to address linear motion on rotary armature is based on the combination of transient time-domain finite element model and frequency-domain slip frequency technique. The results obtained from finite element modeling are then verified by test carried out on experimental model of the motor what validates the proposed method.

Evaluation of Rotor-End Factors in Solid-Rotor Induction Motors

Rotor-end factors are dimensionless quantities used in designing the solid-rotor induction motors to approximate the effects of finite length. It is well known that there are a few analytic estimates of these factors available. With certain, generally acceptable accuracy these match most of the configurations of motors with uniform rotors, but are not adequate for those containing axial slits. In this work, an appropriate three-dimensional model is proposed to numerically evaluate the factors of the rotor-end effect for the uniform (unslitted) and the axially slitted rotors having slits through the whole length. For the two cases these factors are expressed via ratios taken between the rotor powers calculated in three- and two-dimensional systems of coordinates, and are expressed as functions of frequency. The rotor-end factors obtained in such a way are different for the unslitted and slitted rotors. A notable improvement of accuracy is obtained in comparison with the traditional methodology when the numerically evaluated end-factors are used in the two-dimensional circuit-driven frequency-domain finite-element model to determine the motor characteristics.

Fast Steady-State Field-Circuit Model for SMPM-BLdc Motors Driven From 120° and 180° Quasi-Square Wave Inverters

A consistent and computationally efficient finite-element model for the simulation of the steady-state operation of surface-mounted permanent magnet brushless dc motors driven from quasi-square wave inverters is presented. The methodology combines the magnetostatic finite-element and the steady-state time-periodic circuit models with time averaging. A weak field-circuit coupling is established through the effective constant current and lumped parameters estimated at various loading conditions. The performance characteristics, determined via the proposed model for two different motors, are comparable with those obtained from the comprehensive time-stepping finite-element model, with the execution time being approximately a hundred times shorter for the former.

Rotor Shape Optimisation of a Switched Reluctance Motor

In the paper the method of torque pulsations reduction of a switched reluctance motor by means of rotor shape optimization is presented. The optimization procedure is constructed on a basis of a genetic algorithm. The objective function is evaluated using variations of the electromagnetic torque predicted by two-dimensional magnetostatic field analysis. To account for torque pulsations due to current switching a circuit model is used that utilizes the electromagnetic quantities predicted by the finite element analysis. To reduce the time of computations an environment for distributed computing was developed.

Chaotic behavior of new nonlinear electromagnetic microgenerator harvesting energy from mechanical vibrations

A low-frequency nonlinear cantilever-beam-type electromagnetic vibration energy harvester is analyzed. The nonlinearity brought into system kinematics by the “magnets-on-magnets” action provides approximately 20 Hz frequency bandwidth. A simulation study based on solution of coupled dynamic equations of motion and equation of electric balance shows that within major part of the bandwidth the system is capable to produces the voltage with magnitude proportional to magnitude and frequency of the excitation force. At very low frequency and large external forces it falls, however into region where it exhibits chaotic behavior. In this paper the impact of the phenomenon on waveform of the generated voltage is analyzed using the Poincare maps and spectrograms. The results prove a detrimental impact of the phenomenon on overall performance of the system. In order to avoid the chaotic operation the impact of the hard-stop barriers of relative displacement is analyzed showing rise of generated power and reduction of a low-frequency limit of the bandwidth.

Effects of complex motion in a new cantilever-beam nonlinear electromagnetic vibration energy harvester

A new cantilever-beam nonlinear electromagnetic vibration energy harvester with noticeable effects of complex motion composed of relative displacement and torsion of the vibrating element is considered. The analysis of frequency characteristics carried out using the finite element models shows significant differences regarding generated output voltage and frequency bandwidth when detailed 2-d variations of the magnetic force components are taken into account.

Development of FE-based computer-assisted design system for induction machines

This paper describes the software environment for computer assisted design of three-phase squirrel cage induction machines. The finite element method is used as a computational technique to account for detailed geometrical properties, skew, material nonlinearity and deep-bar effect. The system enables determination of all electromagnetic quantities that are usually of interest of the designers of electrical machines. Besides of that it enables the design optimization. The design of experiment is used as a principal method. Sample results of calculations compared with measurements and sample design optimization are presented.