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17 pages, 3479 KiB

Open AccessArticle

Design and Research on the Variable Polar Distance of the Double-Sided Linear Induction Motor for Electromagnetic Catapult

by Xijun Liu, Hao Zhao, Houlong Ai and Zelin Chen

Energies 2025, 18(1), 33; https://doi.org/10.3390/en18010033 - 25 Dec 2024

Cited by 1 | Viewed by 702

Abstract

According to the special technical requirements of carrier-based aircraft catapults, this paper describes the design of a variable pole distance bilateral linear induction motor. When the traditional constant pole motor is used as the catapult of carrier-based aircraft, the current frequency continues to increase during the catapult process, which greatly aggravates the burden of the motor. Therefore, we propose a variable pole length primary double-sided linear induction motor structure. Compared with the traditional constant pole motor structure, this structure can gradually increase the pole distance with an increase in speed when the current frequency remains unchanged. In contrast, the variable pole distance method with a current frequency of 200 Hz has a pole distance of 0.262 m when the displacement is 10 m, and the pole distance increases to 0.352 m when the displacement is 100 m. By maintaining a constant current frequency, this method effectively reduces the control complexity at high speed. Through the theoretical analysis and research calculation conducted on the designed motor, a finite element simulation model was also established by ANSYS 14.0, and the influence of the change in the pole distance on the performance of the motor was analyzed. The magnetic field line and magnetic density distribution of the motor are simulated and analyzed, and the validity of the theoretical calculation is verified. Full article

(This article belongs to the Section F: Electrical Engineering)

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15 pages, 4055 KiB

Open AccessArticle

Combined Propulsion and Levitation Control for Maglev/Hyperloop Systems Utilizing Asymmetric Double-Sided Linear Induction Motors

by Vladimir Kuptsov, Poria Fajri, Md. Rasheduzzaman, Salvador Magdaleno-Adame and Konstantin Hadziristic

Machines 2022, 10(2), 131; https://doi.org/10.3390/machines10020131 - 11 Feb 2022

Cited by 6 | Viewed by 4760

Abstract

This article presents a new method for combined levitation and propulsion control in maglev/Hyperloop systems by selectively applying AC and DC modes of operation to a group of asymmetric double-sided linear induction motors (ADSLIMs). Although adjusting the AC current magnitude of lower and upper primary windings in ADSLIMs allows simultaneous control of thrust and lift forces, the limitation of this current balancing technique prohibits them from producing a high lift force while operating with low thrust force. To overcome this limitation and to simultaneously control the thrust and lift forces of the ADSLIMs with high efficiency under different operating conditions, a combination of AC and DC modes of operation is proposed. AC mode of operation consists of feeding different AC current amplitudes to the upper and lower ADSLIM primary windings to produce and control the required thrust and lift forces. The DC mode of operation consists of controlling one or several ADSLIMs to operate with DC excitation to realize the desired lift force at lower thrusts which otherwise cannot be achieved by operating in AC mode alone. The concept of the new combined control strategy is studied using two-dimensional finite element (FE) electromagnetic simulations and compared with an Inductrack permanent magnet (PM) based passive magnetic levitation system. Full article

(This article belongs to the Special Issue Design and Control of Electrical Machines)

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16 pages, 3539 KiB

Open AccessArticle

Optimal Design of a Short Primary Double-Sided Linear Induction Motor for Urban Rail Transit

by Hanming Wang, Jinghong Zhao, Yiyong Xiong, Hao Xu and Sinian Yan

World Electr. Veh. J. 2022, 13(2), 30; https://doi.org/10.3390/wevj13020030 - 31 Jan 2022

Cited by 3 | Viewed by 3350

Abstract

Linear induction motors (LIMs) have been widely used in rail transit. However, Due to the breaking of the primary core and the large air gap, the efficiency and power factor of LIMs are seriously damaged, causing a large amount of energy waste. To improve the efficiency and power factor of LIMs for urban rail transit, we present a new optimization method for the design of a short primary double-sided linear induction motor (SP-DLIM) with a rated speed of 45 km/h and small thrust. The method is based on a steady state equivalent circuit model and the differential evolutionary algorithm (DEA). Moreover, the design constraints and the objective functions are proposed for the optimization problem. Finally, the optimized SP-DLIM is simulated by 2D transient finite element method (FEM). The 2-D transient FEM results verify the accuracy of the optimization method proposed in this paper. Full article

(This article belongs to the Special Issue Electric Vehicles Integration in Smart Grids)

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15 pages, 2555 KiB

Open AccessArticle

A Novel, Improved Equivalent Circuit Model for Double-Sided Linear Induction Motor

by Qian Zhang, Huijuan Liu, Tengfei Song and Zhenyang Zhang

Electronics 2021, 10(14), 1644; https://doi.org/10.3390/electronics10141644 - 10 Jul 2021

Cited by 5 | Viewed by 3354

Abstract

A novel, improved equivalent circuit model of double-sided linear induction motors (DLIMs) is proposed, which takes the skin effect and the nonzero leakage reactance of the secondary, longitudinal, and transverse end effects into consideration. Firstly, the traditional equivalent circuit with longitudinal and transverse end effects are briefly reviewed. Additionally, the correction coefficients for longitudinal and transverse end effects derived by one-dimensional analysis models are given. Secondly, correction factors for skin effect, which reflects the inhomogeneous air gap magnetic field vertically, and the secondary leakage reactance are derived by the quasi-two-dimensional analysis model. Then, the proposed equivalent circuit is presented, and the excitation reactance and secondary resistance are modified by the correction coefficients derived from the three analytical models. Finally, a three-dimensional (3D) finite element model is used to verify the proposed equivalent circuit model under varying air gap width and frequency, and the results are also compared with that of the traditional equivalent circuit models. The calculated thrust characteristics by the proposed equivalent circuit and 3D finite element model are experimentally validated under a constant voltage–frequency drive. Full article

(This article belongs to the Special Issue Robust Design Optimization of Electrical Machines and Devices)

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13 pages, 2058 KiB

Open AccessArticle

2D Hybrid Steady-State Magnetic Field Model for Linear Induction Motors

by Samuil R. Aleksandrov, Timo T. Overboom and Elena A. Lomonova

Math. Comput. Appl. 2019, 24(3), 74; https://doi.org/10.3390/mca24030074 - 25 Jul 2019

Cited by 1 | Viewed by 3436

Abstract

This paper presents a 2D hybrid steady-state magnetic field model, capable of accurately modeling the electromagnetic behavior in a linear induction motor, including primary slotting, finite yoke length, and longitudinal end-effects by primary motion. This model integrates a complex harmonic modeling technique with a discretized magnetic equivalent circuit model. The Fourier model is applied to regions with homogeneous material properties, e.g., air regions and the track of the motor, while the magnetic equivalent circuit (MEC) approach is used for the regions containing non-homogeneous material properties, e.g., the primary of the linear induction motor (LIM). By only meshing the domains containing highly-permeable materials, the computational effort is reduced in comparison with the finite element method (FEM). The model is applied to a double-layer single-sided LIM, and the resulting thrust and normal forces show an excellent agreement with respect to finite element analysis and measurement data. Full article

(This article belongs to the Special Issue Mathematical Models for the Design of Electrical Machines)

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13 pages, 3168 KiB

Open AccessArticle

Variable Pole Pitch Electromagnetic Propulsion with Ladder-Slot-Secondary Double-Sided Linear Induction Motors

by Jun Di, Yu Fan, Yajing Liu, Sijia Liu and Yulong Zhu

Appl. Sci. 2017, 7(5), 481; https://doi.org/10.3390/app7050481 - 6 May 2017

Cited by 5 | Viewed by 6520

Abstract

In this paper, we propose a novel variable pole pitch (VPP) electromagnetic (EM) propulsion technique using a series of ladder-slot-secondary double-sided linear induction motors (LS-secondary DLIMs). An equivalent circuit is developed for the LS-secondary DLIM, which considers the distribution of the eddy current in the ladders and the end effect. This equivalent circuit forms the basis for the subsequent design, numerical analysis, and optimization. The primary purpose of the VPP EM propulsion system is to address several obstacles encountered in high-speed large-thrust applications of LIMs, such as power factor improvement, optimization considering supply frequency constraint and operating kinetics, etc. The equivalent circuit of the LS-secondary DLIM, i.e., the theoretical foundation of the VPP EM propulsion, has been validated via simulation and experimentation on a small-scale platform, which proves that the numerical analysis of the VPP EM propulsion is effective. Full article

(This article belongs to the Section Energy Science and Technology)

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