Mladen Trlep

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 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 simulation of the soil ionization phenomenon around the grounding system by the finite element method

A simulation model based on finite-element method is presented to simulate the soil ionization phenomenon around the grounding system. The advantage of the methodology proposed in this study against analytical methods is that both simple and complex grounding systems buried in homogeneous or nonhomogeneous soil taking into account soil breakdown process can be modeled. The suggested modeling is validated by comparison of the calculated results, which are laid out for grounding rod and grounding grid, with experimental tests results and simulations results found in literature. The performance of grounding system, considering the soil ionization effect at high-magnitude current, is also compared with the one not considering the soil ionization effect

Design and Finite-Element Analysis of Interior Permanent Magnet Synchronous Motor With Flux Barriers

The paper presents a finite-element method-based design and analysis of interior permanent magnet synchronous motor with flux barriers (IPMSMFB). Various parameters of IPMSMFB rotor structure were taken into account at determination of a suitable rotor construction. On the basis of FEM analysis the rotor of IPMSMFB with three-flux barriers was built. Output torque capability and flux weakening performance of IPMSMFB were compared with performances of conventional interior permanent magnet synchronous motor (IPMSM), having the same rotor geometrical dimensions and the same stator construction. The predicted performance of conventional IPMSM and IPMSMFB was confirmed with the measurements over a wide-speed range of constant output power operation.

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.

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.

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.