Marko Jesenik

Analysis of interior permanent magnet synchronous motor designed for flux weakening operation

The paper presents a finite element method (FEM) based analysis of interior permanent magnet synchronous motor, designed for flux-weakening operation. Flux-weakening performance determined from the FEM analysis on the proposed permanent magnet motor structure is presented in order to verify the suitability of the design concept for flux-weakening operation. The influence of iron losses on the output power capability is included in the analysis by posterior iron loss calculation. The presented interior permanent magnet motor shows an extremely wide constant-power speed range which exceeds 5:1.

The FEM-BEM analysis of complex grounding systems

This paper shows the use of the hybrid finite-boundary element method (HM) in the analysis of complex grounding systems (GS) designed for protection of power and industrial systems. In the field calculation a three-dimensional (3-D) linear finite element and a 3-D mixed boundary element were applied. The program solution used is suitable for any GS and for isotropic or anisotropic soil properties.

Field homogeneity in a two-phase round rotational single sheet tester with one and both side shields

Round rotational single sheet tester is used for the measurement of magnetic properties in rotational and alternating magnetic fields. The influence of one and both side shields on the field homogeneity in the sample is investigated with finite element calculation. The aim of the calculation is to define the optimal position of one or both side shields in order to expand the rotational field homogeneity area. We want to reach the area of the homogeneous field as large as possible. The best result is achieved with two sides shielding.

Electric Field Distribution Under Transmission Lines Dependent on Ground Surface

This paper deals with the calculation of the electric field in the vicinity of a high-voltage overhead transmission line (TL). Since analytical formulas cannot be used to calculate the electric field in cases when the ground surface under a TL is not flat or when conducting bodies are located under it, we present the use of finite element method (FEM) for this purpose. The electric field distribution has been analyzed for two characteristic high-voltage TLs. A graphical comparison of the electric field strength E 1 m above ground surface is included.

Unreliable determination of vector B in 2-D SST

Rotations of vector B in a square rotational single sheet tester and a round rotational single sheet tester were compared. Two pairs of B coils (45° displaced) were used to control and verify the rotation of vector B at different coil diameters. It was clarified that two sinusoidal induced voltages in B coils do not ensure the rotational flux condition in the area inside the B coils in the sample, especially in a larger measuring region.

Increasing of output power capability in a six-phase flux-weakened permanent magnet synchronous motor with a third harmonic current injection

This paper presents a FEM based analysis of output power capability improvement (OPC) in a six-phase flux-weakened permanent magnet synchronous motor with a harmonic current injection. It is shown that the flux-weakened permanent magnet synchronous motor with the third harmonic current injection is capable of producing more output torque per RMS current flowing through the windings than the same motor supplied with sinusoidal currents. The results of the analysis are partially verified with the measurements.

Hysteresis model and examples of ferromagnetic materials

This work deals with the application of the scalar product model to different ferromagnetic materials. Different hysteresis curves and minor loops are measured to examine the behavior of the magnetization and to compare it with theoretical calculated curves.

Automatic 2D Discretization with Variable Mesh Density for Numerical Methods

Most of the time necessary to solve a problem by finite element method is spent for the data generation. Consequently, the best solution for the user is automatic data generation. It is advantageous to generate a mesh with varying density in different areas in dependence on the given problem. An automatic data generation consists of the subdivision into convex subregions, the creation of nodes and elements, and the correction of discretizated areas, which affects the accuracy of calculation 2,3,4

Analytical modelling of a magnetization curve obtained by the measurements of magnetic materials properties using evolutionary algorithms

Display Omitted Determination of the new analytic expression describing measured magnetization curves.We tested standard and evolutionary methods for the determination of parameters.Used methods are evaluated statistically using average values, cross-validation, CRS4EAs, and the Holm test.We made modification of the best evolutionary method and a new, better approach has been obtained.The presented solution can be used to prepare magnetic material data for any FEM software. Magnetization curves are obtained with measurements and used for the description of magnetic material properties. In the case where the curve is rough problems can appear during the Finite Element Method (FEM) calculations. One of the solutions is the use of an analytically written curve, which fits the measured curve. In this paper different analytical expressions are tested on different measured magnetization curves and compared with each other. Different evolutionary methods are used and tested for the determination of the analytical expressions parameters: The Genetic Algorithm, Differential Evolution with three different strategies, Teaching-Learning Based Optimization and Artificial Bee Colony. To obtain credible and optimal results, we made a statistic evaluation of the results using Cross-validation, CRS4EAs (Chess rating system for evolutionary algorithms), and the Holm test. Based on the tests results we improved the more appropriate evolutionary method, which was Artificial Bee Colony, using the Levenberg-Marquardt algorithm. As a result, two different methods: are presented and tested which combine Artificial Bee Colony and the Levenberg-Marquardt algorithm. An analytical expression is presented which can be used for a wide range of different materials curves and also a stable and efficient method for the determination of the analytical expressions parameters. The presented solution is appropriate to be used together with, or as a part of, FEM calculation software. For preparation of magnetic material data the presented solution can be used as an independent programme for the transformation of the H-B table of values presenting not-smooth measured magnetic material curves (or measured with too few points) into the H-B table of values presenting smooth magnetic material curve which can be used as input data for any FEM software.

Power Capability and Flux-Weakening Performance of Interior Permanent Magnet Synchronous Motor With Multiple Flux Barriers

The paper presents a comparison of electromagnetic torque, output power capability and flux-weakening performance of interior permanent magnet synchronous motor with flux barriers (IPMSMFB) with performances of conventional interior permanent magnet synchronous motor (IPMSM). The calculated performance of conventional IPMSM was confirmed with the measurements in the range of speed 3000-10000 rpm