International Journal of Applied Electromagnetics and Mechanics - Volume 68, issue 4

Authors: Chen, Qixu | Li, Guoli | Qian, Zhe | Cao, Wenping | Wang, Qunjing

Article Type: Research Article

Abstract: A holographic spectrum method (HSM) of multi-phase and multi-layer winding magnetomotive force (MMF) for 12-slot/10-pole combination with fractional-slot concentrated-winding (FSCW) is proposed in this paper. Taking two kinds of traditional winding layout as example, amplitude and phase distribution of the v th harmonic are calculated. The holospectrum of the multi-phase and multi-layer winding are derived based on three-phase single-layer (TP-SL) and three-phase double-layer (TP-DL) holospectrum theory. Then the finite element method (FEM) is used to validate the resultant winding MMF calculated by the holospectrum method. Results show that two methods have a good consistency in changing tendency. Prototype manufacture and …test of axial-flux PMSM with a double-three-phase four-layer (DTP-FL) winding have been completed. A load experiment with two groups of resistance is established to validate its output power of axial-flux permanent magnet synchronous machine (PMSM). The temperature distribution of axial-flux PMSM is evaluated with PT100 and infrared thermal imager. The experiments shows that the axial-flux PMSM runs at a relative temperature rise. Show more

Keywords: Fractional-slot concentrated winding (FSCW), holographic spectrum method, axial-flux permanent magnet synchronous machine (PMSM), multi-phase and multi-layer winding, winding MMF

DOI: 10.3233/JAE-210025

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 68, no. 4, pp. 387-403, 2022

Authors: Chen, Jun-Wei

Article Type: Research Article

Abstract: For precision engineering, a linear PM-moving actuator with trapezoidal PMs and trapezoidal coils considering the fringing effect is proposed. To take into account the effect of the finite-long trapezoidal PM array, an improved Fourier series expansion is developed to calculate the fringing-included magnetic field. Then the full-stroke thrust excited by the trapezoidal coils is accurately predicted and validated by the finite element method. Sensitivity of the trapezoidal parameters of PMs and coils is analyzed, and combined optimization is implemented by the genetic algorithm. Through the Pareto optimal solutions of thrust, the relation of the PM-coil parameter combination is described and …formulated by curve fitting. Compared with the traditional rectangular PM actuators or other trapezoidal-typed actuators, the proposed actuator with trapezoidal PMs and coils further decreases the thrust ripple and largely increases the thrust magnitude simultaneously, and reaches an utmost-close effective stroke as well. Show more

Keywords: Trapezoidal PMs, trapezoidal coils, linear PM actuator, fringing effect, Fourier series expansion, combined optimization

DOI: 10.3233/JAE-210050

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 68, no. 4, pp. 405-425, 2022

Authors: Xia, Zhengrong | Pei, Yongchen | Wang, Dongxu | Wang, Shun

Article Type: Research Article

Abstract: Although permanent magnet couplings (PMCs) have been under research for many years and have found successful industrial applications, this is still a technology under development. Accurate parameter determination is of significance for performance analysis and critical decisions on PMC design. However, the determination can often lead to an unacceptable increase in computation, especially when the finite element (FE) method is used. The study aims to develop an FE model that is used for the structural design of a standard-disc type PMC for optimal torque. For the quick and accurate design, an integration optimal solution of the response surface methodology (RSM) …and the Taguchi’s method was proposed. To verify the simulation, a series of experimental investigations were conducted on a self-developed testing platform. Furthermore, for a minimum set of FE analyses (FEA), a quantitative indicator called contribution rate, which can reflect effect level of structure parameters on the torque, was given based on the Taguchi method. Apart from this, the orthogonal matrix was used for the reduction of the FE calculation. Based on the contribution rate, the response surface methodology was adopted for the optimal torque determination with no increase in the PM volume. According to the optimization results, a fitting formula, which considers the contribution rates of the optimization variables, was presented. The results suggest that the FE simulations agree very well with the experiments, and the fitting formula can be used in the PMC design. Show more

Keywords: Permanent magnet coupling, structure optimization, contribution rate, Taguchi method, RSM

DOI: 10.3233/JAE-210094

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 68, no. 4, pp. 427-444, 2022

Authors: Wei, Mingrui | Chen, Yuyao | Wang, Wenhui | Guo, Guanlun

Article Type: Research Article

Abstract: In order to understand the performance and internal parameter distribution of SOFC fueled by methane mixture in detail, the paper uses numerical simulation method to conduct three-dimensional multiphysics coupling simulation on a single-channel anode-supported planar SOFC. The uniqueness of the three-dimensional model is that it employs the anode exchange current density from the methane gas mixture and considers the electrochemical oxidation of carbon monoxide. The numerical model proposed in this work provides more accurate simulation results. The results show that compared with the model that uses the exchange current density equation from humidified hydrogen for simulation, the model that uses …the exchange current density equation from methane mixture to simulate the performance curve is closer to the experimental value. When using methane gas mixture as fuel, the maximum temperature difference along the flow direction is 10 K and the maximum power density can reach 0.482 W/cm2 . In the thickness direction of the SOFC, the current density is not much different at the inlet and outlet. Along the direction of flow, the current density decreases near the inlet and outlet. Reducing the rate of fuel flow or increasing gas inflow temperature can improve SOFC performance. Show more

Keywords: Solid oxide fuel cell, methane steam reforming, exchange current density equation, performance, numerical modeling

DOI: 10.3233/JAE-210107

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 68, no. 4, pp. 445-460, 2022

Authors: Teng, Yue | Ai, Mengmeng | Shan, Yi | Xu, Yongming | Qi, Yulin

Article Type: Research Article

Abstract: In this paper, a large oil-immersed self-cooling power transformer with a capacity of 180 MVA and a voltage grade of 220 kV is taken as the research object, and the global fluid network model of the transformer is established according to the oil circuit structure of the transformer and the circulation path of the cooling medium. Based on the decoupling method of fluid network, a three-dimensional finite element calculation model of local fluid field and temperature field is established at the decoupled location. Finally, the hot spot temperature of the winding appears at the 5th layer of the high-voltage winding, which is …89.2 °C, and the lowest temperature appears at the bottom of the low-voltage winding, which is 55.1 °C. The top oil temperature is 69.2 °C, and the bottom oil temperature is 47.6 °C. The temperature experiment of the prototype shows that the relative error of the calculation result of the hot spot temperature of the high voltage winding is 4.45%, the relative error of the calculation result of the hot spot temperature of the medium voltage winding is 4.43%, and the relative error of the calculation result of the hot spot temperature of the low voltage winding is 3.58%. It proves the accuracy of the global fluid network decoupling method to calculate the global temperature of the transformer, which provides a reference for the prediction of the global temperature of the transformer. Show more

Keywords: Oil-immersed self-cooling power transformers, fluid network decoupling, field–circuit coupling, full-domain temperature prediction

DOI: 10.3233/JAE-210135

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 68, no. 4, pp. 461-481, 2022

Authors: Yang, Mao | Zhang, Hong | Zhou, Jianting | Jiang, Hejing | Zheng, Yu | Qiu, Jian

Article Type: Research Article

Abstract: Both corrosion defects and stress can cause magnetic field mutations, so the effect of stress must be considered in the magnetic detection of steel corrosion. This paper focuses on exploring the influence law of tension on magnetic signals of the corroded specimens. Based on the spontaneous magnetic leakage mechanism of steel bar corrosion and the stress magnetization model, the magnetic memory detection of corroded reinforced concrete under tension was carried out. The magnetic characteristics of corroded specimens before and after loading were analyzed. The corrosion positions of the specimens can be determined according to the representative mutation points (RMP) of …the B yc (0) curves, and the magnetic index I 2 was proposed to roughly determine the corrosion degree of the specimens when the specimens were not subjected to tensions. The experimental results showed that the RMP of B yc (F ) curves can still represent corrosion positions when the specimens were under tension. The theoretical derivation showed that the magnetic field change caused by tensile force is limited, and the maximum value of the magnetic field change caused by tensile force can be obtained. Based on this, the corresponding I 3 -F curves were obtained through the test. The magnetic field change caused by the most unfavorable tensions was calculated to analyze its influence on corrosion magnetic detection. Compared with I 2 , the relationship between I 3 and the corrosion degree was more discrete, indicating that tensile forces affected the quantitative detection of corrosion. Still, the magnetic field caused by corrosion played a leading role. The verification showed that the measured corrosion positions of reinforced concrete specimens were in good agreement with those detected by the magnetic memory method. Show more

Keywords: Corrosion, reinforced concrete, magnetic memory detection, tensile load, influence law

DOI: 10.3233/JAE-210172

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 68, no. 4, pp. 483-499, 2022