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Energies 2018, 11(1), 134;

Magnetic Field and Torque Output of Packaged Hydraulic Torque Motor

School of Automation Science and Electrical Engineering, Beihang University, Beijing 100083, China
Research Institute of Beihang University in Shenzhen, Shenzhen 518057, China
AVIC Xian Flight Automatic Control Research Institute, Xi’an 710065, China
Department of Electrical and Electronic Engineering, University of Nottingham, Nottingham NG7 2RD, UK
Author to whom correspondence should be addressed.
Received: 17 November 2017 / Revised: 23 December 2017 / Accepted: 25 December 2017 / Published: 5 January 2018
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Hydraulic torque motors are one key component in electro-hydraulic servo valves that convert the electrical signal into mechanical motions. The systematic characteristics analysis of the hydraulic torque motor has not been found in the previous research, including the distribution of the electromagnetic field and torque output, and particularly the relationship between them. In addition, conventional studies of hydraulic torque motors generally assume an evenly distributed magnetic flux field and ignore the influence of special mechanical geometry in the air gaps, which may compromise the accuracy of analyzing the result and the high-precision motion control performance. Therefore, the objective of this study is to conduct a detailed analysis of the distribution of the magnetic field and torque output; the influence of limiting holes in the air gaps is considered to improve the accuracy of both numerical computation and analytical modeling. The structure and working principle of the torque motor are presented first. The magnetic field distribution in the air gaps and the magnetic saturation in the iron blocks are analyzed by using a numerical approach. Subsequently, the torque generation with respect to the current input and assembly errors is analyzed in detail. This shows that the influence of limiting holes on the magnetic field is consistent with that on torque generation. Following this, a novel modified equivalent magnetic circuit is proposed to formulate the torque output of the hydraulic torque motor analytically. The comparison among the modified equivalent magnetic circuit, the conventional modeling approach and the numerical computation is conducted, and it is found that the proposed method helps to improve the modeling accuracy by taking into account the effect of special geometry inside the air gaps. View Full-Text
Keywords: packaged torque motor; numerical analysis; magnetic field distribution; magnetic saturation; output performance of torque; mathematical model packaged torque motor; numerical analysis; magnetic field distribution; magnetic saturation; output performance of torque; mathematical model

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Yan, L.; Duan, Z.; Zhang, Q.; Niu, S.; Dong, Y.; Gerada, C. Magnetic Field and Torque Output of Packaged Hydraulic Torque Motor. Energies 2018, 11, 134.

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