Anton Hamler

Evaluation of saturation and cross-magnetization effects in interior permanent-magnet synchronous motor

The paper presents the evaluation of saturation and cross-magnetization effects in interior permanent magnet synchronous motor (IPMSM) over the entire range of direct and quadrature axis excitation. The conventional two-axis machine model is modified in order to include the influence of saturation and cross-coupling effects on the variation of self and cross-coupling inductances in the direct and the quadrature axis. The two-axis machine model parameters are evaluated by experiments performed on a IPMSM using a controlled voltage source inverter and are compared with parameters values evaluated by the finite element method. The evaluation of two-axis machine model parameters reveals significant saturation and cross-magnetization effects in both axes, especially in the flux-weakening regime.

Analysis of iron loss in interior permanent magnet synchronous motor over a wide-speed range of constant output power operation

The paper presents the analysis of iron loss in interior permanent magnet synchronous motor over a wide-speed range of constant output power operation. The analysis is based on finite element method and uses the information on local flux density variation in the motor components. The total iron loss is calculated by summing up separately the hysteresis, classical eddy current and excess losses for each element of discretization over one electrical cycle of magnetic field variation in all parts of motor iron. The results of iron loss calculation were compared with the results obtained from experiments on the actual machine.

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.

Determination of the Heating Effect of Magnetic Fluid in Alternating Magnetic Field

In this paper, we have investigated the heating power of magnetic fluid, when exposed to a high-frequency magnetic field. Commercially available sample of magnetic fluid has been used and some basic investigation revealed maghemite ¿-Fe2O3 particles with 10.9-nm mean diameter and 10.57% volume concentration. We present an improved experimental system, capable of generating homogeneous magnetic field of amplitudes up to 4 kA/m and frequencies from 10 kHz to 1 MHz. In this paper, none of the heating generation mechanisms (NE¿el or Brownian relaxation or eddy current losses) have been determined solemnly, therefore, the outcome of their activity has been examined by two methods. In case of calorimetric measurements method key parameter is temperature rise while in case of magnetic measurement method key parameters are time-dependent magnetic field strength H and appurtenant magnetic flux density B. Calorimetric measurements are performed and used to determine specific absorption rate curve. Alternatively, this curve has been obtained with the measurement of B(t) and H(t), when a sample is exposed to the same magnetic conditions. Integration of the hysteresis loops has resulted in loss power of the fluid. Proposed magnetic measurement methods proved to be a decent alternative in the process of determining losses.

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.

Cross magnetization effect on inductances of linear synchronous reluctance motor under load conditions

The paper deals with the Finite Element Method (FEM) based procedure for determination of operating point dependent inductances of a Linear Synchronous Reluctance Motor (LSRM). Special attention is paid to the effects of cross magnetization and saturation on the inductances of LSRM under load conditions. To achieve a deeper insight into the cross magnetization and the saturation phenomena a standard two-axis LSRM dynamic model is modified. The modified dynamic LSRM model contains explicit terms for the direct and the quadrature axis self-inductances and explicit terms for the cross coupling inductances. The last ones appear as a consequence of the cross coupling between the direct and the quadrature axis. All inductances of the modified LSRM model are current dependent.

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.

Optimal secondary segment shapes of linear reluctance motors using stochastic searching

The authors discuss the influence of the shape of secondary segments of linear reluctance motors on the force. The magnitudes studied are the moving and the attractive force as they oscillate depending on the position of the primary. The magnetic conditions of the motor were analyzed by the finite element method, and the forces were calculated by the Maxwell stress method. The stochastic search method was used to change the shape of secondary segments.

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.