International Journal of Applied Electromagnetics and Mechanics - Volume 63, issue 4

Authors: Du, Chuanbao | Liu, Zheng | Mao, Congguang | Qin, Feng | Cui, Zhitong | Sun, Dongyang

Article Type: Research Article

Abstract: This paper examines with statistical analysis of transient response for typical vehicle mounted antenna - monopole on conductive plane varying multiple random field parameter distributions of high-altitude electromagnetic pulse (HEMP) by employing the combinations of Method of Moment (MoM) method and a high computational efficiency statistical analysis tool called polynomial chaos expansion method (PCEM).The main procedures of the combination method are composed of two following steps: Firstly, the frequency-domain transfer function of the antenna port response for the monopole is derived by using MoM and then the transient current response is obtained with inverse Fourier transform; Secondly, the statistical model …with multiple random input parameters are calculated by PCEM according to the transient response data. The statistical indicators of the model concentrate on the confidence interval of the transient response, the Probability Density Function (PDF) and Cumulative Probability Density Function (CDF) of the current peak. The paper not only focuses on the random radiated field parameter such as elevation, azimuthal angle, polarization angle and magnetic dip angle but also considers height of burst, ratios of plane length versus antenna height, and antenna down-tilt angles. The analysis results demonstrate the validation of the proposed statistical method and provide the reference base for system HEMP survivability evaluation and protection design. Show more

Keywords: Monopole, HEMP, uncertainty analysis, MoM, PCEM, transient response

DOI: 10.3233/JAE-190125

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 63, no. 4, pp. 551-566, 2020

Authors: Li, Jiahao | Yang, Guolai | Fan, Yumeng

Article Type: Research Article

Abstract: This paper investigates the braking force characteristic of permanent magnet eddy current brake with high acceleration. Compared with the braking force characteristics under quasi-static condition, the braking force considering the effect of high acceleration lags behind the quasi-static braking force before and after the critical speed. Meanwhile, there is a transition phase near the critical speed, and the peak value of the braking force is higher than that in the quasi-static approximation. The calculation of braking force under quasi-static condition is derived by solving the boundary value problem. The accuracy of the analytical model and the finite element model is …verified through comparing the results of both models. The influence factors on the braking force characteristics are further analyzed. The results show that the increasing of the conductivity, thickness of conductor plate and the length of the permanent magnets can increase the effect of acceleration. The effect of acceleration has little relation with the permanent magnet height and the air gap length. Show more

Keywords: Eddy current brake, electromagnetic force analysis, high acceleration, permanent magnets

DOI: 10.3233/JAE-190141

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 63, no. 4, pp. 567-581, 2020

Authors: Qin, Jinchang | Chen, Renwen | Zhang, Yuxiang | Liu, Chuan

Article Type: Research Article

Abstract: This paper proposes a new virtual Halbach analytical method for improved Halbach permanent magnet (PM) slotless planar linear actuators, which have mixed neodymium iron baron (NdFeB) magnets and ferrite magnets to form a two-segment quasi-Halbach topology with different heights of main and auxiliary magnetic poles. The method has four steps, which are described in detail in the paper. One of the key steps is to visually regard the permanent magnet region magnetized only in the y direction as a Halbach array structure with a magnetization amplitude of 0 in the x direction that satisfies the Newman boundary condition. …The investigation shows that the results of the new analytical method are in good agreement with the finite element method. Using this analytical method, the effect of improved Halbach permanent magnet slotless planar linear actuator with unequal height of the main and auxiliary magnetic poles on the magnetic field waveform is analyzed by means of a parametric research. Show more

Keywords: Analytical, Halbach, magnetic field, permanent magnet (PM)

DOI: 10.3233/JAE-190145

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 63, no. 4, pp. 583-599, 2020

Authors: Li, Lei | Yang, Guolai | Li, Zhaohui

Article Type: Research Article

Abstract: This study focused on the damage of permanent magnets(NdFeB) in the electromagnetic buffer under the intensive impact load. According to the constitutive characteristics of the permanent magnets, a constitutive model suitable for NdFeB called damage-modified ZWT was determined. Furthermore, the specific parameters in the constitutive model were determined by fitting the constitutive curve. Then the incremental expression was established for the constitutive model and the model was embedded into ABAQUS via the VUMAT subroutine interface. A dynamic model of the electromagnetic buffer was established and calculated. After that the evolution and distribution law of damage in permanent magnets under the …intensive impact load were clarified by analyzing the finite element results. Finally the damage of the device is reduced by optimizing the geometric parameters. The results show that the permanent magnets near the inner ring are damaged more from the radial distribution of the damage and the permanent magnets on both sides are damaged more from the lateral distribution of the damage, which provides a reference for the design of electromagnetic buffers. Show more

Keywords: Intensive impact load, the damage in permanent magnets, damage-modified ZWT constitutive model, VUMAT subroutine

DOI: 10.3233/JAE-190147

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 63, no. 4, pp. 601-620, 2020

Authors: Pottie, Daniel Leon Ferreira | Mendonça, Gabriel Alves | Faria, Osvane Abreu | Faria, Marco Tulio Correa | Cardoso Filho, Braz de Jesus | Maia, Thales Alexandre Carvalho

Article Type: Research Article

Abstract: In this paper, the design criteria, assembly practices and experimental analysis of a low cost micro generation system are presented. A high-power density microturbine is specially devised using a stock automotive turbocharger. The project concept is evolved to achieve satisfactory operating conditions. The main practical challenges to achieve the desirable output performance are discussed from the electromechanical perspective including an extensive vibration analysis during operation. The balancing procedure is proven to be a keystone requirement for safe operation at higher rotational speeds. Characterizing the electromechanical interaction between the components is a crucial requirement in the design process. The microturbine is …tested using steady inlet compressed air flow, with accelerometers installed on each bearing. The described design and assembly procedures allow the unloaded microturbine to run safely up to 100000 rpm. Show more

Keywords: Electromechanical design, electrical machine, high-speed balancing, microturbine, turbocharger

DOI: 10.3233/JAE-190166

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 63, no. 4, pp. 621-644, 2020

Authors: Lecointe, Jean-Philippe | Napieralska, Ewa | Demenko, Andrzej

Article Type: Editorial

DOI: 10.3233/JAE-209200

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 63, no. 4, pp. 647-647, 2020

Authors: Wojciechowski, Rafal M. | Kurzawa, Milena | Jedryczka, Cezary

Article Type: Research Article

Abstract: The paper discusses the strategy of searching for the extreme of multi-modal functions with the number of decision variables n ≥ 6, in a multidimensional design space. The optimization algorithm combining an evolution strategy (ES) with operators of a genetic algorithm has been proposed. The method of selecting subspaces that allows for narrowing of the design space has been proposed. The effectiveness of the proposed approach has been demonstrated on two selected test systems with eddy currents. First, the equivalent multi-branch Foster circuit of a solenoid coil with a massive conducting core has been determined. Next, the proposed …approach has been applied in the analysis of a high frequency transformer, working in a wireless power transmission (WPT) system. In the second case, the equivalent circuit of the transformer has been formed by means of multi-branch Cauer circuits. Selected results of the calculations have been presented and discussed. The obtained results have been compared with the results of the performed finite element analysis (FEA) of the considered test systems. Show more

Keywords: Optimization, genetic algorithm, eddy current problem, Foster circuit, Cauer circuit

DOI: 10.3233/JAE-209201

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 63, no. 4, pp. 649-659, 2020

Authors: Darques, Kévin | Tounzi, Abdelmounaïm | Le Menach, Yvonnick | Korecki, Julien | Beddek, Karim

Article Type: Research Article

Abstract: Shaft voltage is present in all electrical machines and can be useful as a diagnosis variable once the effect of some defects on this quantity is well quantified. 2D numerical models have already been used to tackle this point but 3D effects due to end windings can also have a significant influence on this voltage. This paper deals with the study of a turbo-generator using a 3D finite element model in order to investigate this task. In this aim, two finite element models in 2D and 3D of a high power turbo-generator are performed. The effect of three common defects …on the shaft voltage is investigated while taking into account the nonlinear behaviour of ferromagnetic materials and the armature winding of the stator. Results with both models are analyzed and compared. Show more

Keywords: Fault diagnosis, finite element method, electromagnetism, shaft voltage, synchronous generator

DOI: 10.3233/JAE-209202

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 63, no. 4, pp. 661-671, 2020

Authors: Zidat, Farid | Mavrudieva, Diana | Lombard, Patrick | Bauw, Grégory | Cassoret, Bertrand | Lecointe, Jean-Philippe

Article Type: Research Article

Abstract: This paper describes a new method to identify the equivalent circuit parameters from finite element modelling and optimisation tool. The optimisation strategy is interesting one, because it allows to find a set of equivalent circuit parameters with only 4 known results instead of solving a polynomial of degree six (or more) and then looking for more known variable and results. The proposed method has three highlight points. The first point is that this new method will make it possible to split stator and rotor leakage inductances. The second one is that the equivalent circuit parameters are depending on working point …saturation state. The last one is that the used quantities can be extracted either from modelling or from measurements. Show more

Keywords: Induction motor, equivalent circuit, finite element, identification method

DOI: 10.3233/JAE-209203

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 63, no. 4, pp. 673-679, 2020

Authors: Hamdinou, Sidi | Roger, Daniel | Rossi, Mathieu | Belgrand, Thierry

Article Type: Research Article

Abstract: The paper presents the concept of a medium frequency transformer built with thin grain oriented electrical steel (GOES) sheets and high temperature windings; this transformer will be associated with power converters for building a solid-state transformer (SST) used in DC grids. The aim of the study is to bring answers about the maximum operating frequency and flux density that provide the maximum power density and efficiency. A thermal model built from tests on the prototype is presented. This thermal model gives a prediction of the transformer performance for the initial choices of frequency and flux density. It opens perspectives for …designing high power density medium-frequency (MF) transformers. Show more

Keywords: Solid-state transformer (SST), medium frequency power transformer, thermal modeling, grain oriented electrical steel (GOES)

DOI: 10.3233/JAE-209204

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 63, no. 4, pp. 681-689, 2020

Authors: Aydoun, Racha | Parent, Guillaume | Lecointe, Jean-Philippe | Tounzi, Abdelmounaïm

Article Type: Research Article

Abstract: This paper deals with the development of a simplified numerical model with the aim of assessing the impact of using grain-oriented electrical steel (GOES) in switched reluctance machine (SRM) on its performance. Different grades of steel are studied to firstly analyze their impact on the inductance and the electromagnetic torque change. Then, both the simplified model and the steel grades helped determine the level of contribution of anisotropy and high permeability individually. In this paper, the impact on electromagnetic torque is evaluated along with a local analyses of the flux lines distribution and the numerical model allows to draw conclusions …on the device performance when anisotropy is introduced. Although the GOES numerical model used for finite elements simulations is not a fully developed model, it is accurate enough for our study. The originality of this paper lies in the fact that the developed model is relatively simple and accurate enough to investigate all the electromagnetic phenomena and draw conclusions which can be applicable to a more complex and time-consuming electromagnetic device. The second original aspect is the introduction of GOES in an axial flux SRM (AFSRM). Show more

Keywords: Anisotropy, axial flux switched reluctance machine, grain oriented electrical steel, axial flux, electromagnetic torque, inductance

DOI: 10.3233/JAE-209205

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 63, no. 4, pp. 691-703, 2020

Authors: Koteras, Dariusz | Tomczuk, Bronislaw

Article Type: Research Article

Abstract: The comparison of three field methods for homogenization of the laminated cores has been presented in this work. As a result, the equivalent electrical conductivity and magnetic permeability for the geometry of the core entire body were obtained for magnetic field 3D modelling. The first method is an iterative homogenization method (IHM) connected with the field solution, whereas the two others are based on analytical expressions arising from the Maxwell’s equations. For 3D field solution, Finite Element numerical model including eddy currents under various frequency values was used in IHM. The model is based on a combination of the …total and the reduced magnetic potentials. For comparison to our IHM, the two analytical approaches for core homogenization were used, as well. To calculate the stray losses in the homogenized laminated C-core these three approaches have been executed, as a case study. Applying suitable simplifications, according the methods of analytical homogenization, between the analytically calculated and measured values of the core losses high differences have been obtained. For the cores from amorphous strip, the analytical methods are inappropriate and our method, though iteratively implicit, gives significantly better equivalent parameters for the laminated C-core. Show more

Keywords: Implicit iterative method, equivalent conductivity, eddy current losses, homogenization methods

DOI: 10.3233/JAE-209208

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 63, no. 4, pp. 705-714, 2020

Authors: Roger, Daniel | Vélu, Gabriel | Ait-Amar, Sonia | Babicz, Sylvain

Article Type: Research Article

Abstract: The paper proposes a comparative approach of two wire technologies for making compact coils able to operate in high temperature (HT°) machines. The first technology is based on ceramic-coated round wire associated with a HT° cement. The second one uses anodized aluminum strips. The advantages and drawbacks of the two technologies are compared, considering the machine global performances at high temperatures.

Keywords: High temperature machine, inorganic insulation, thermal equivalent circuits

DOI: 10.3233/JAE-209209

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 63, no. 4, pp. 715-724, 2020