One dimensional analytical model considering end effects for analysis of electromagnetic pressure characteristics of annular linear induction electromagnetic pump

2022 ◽  
Vol 165 ◽  
pp. 108766
Author(s):  
Zhenyang Zhang ◽  
Huijuan Liu ◽  
Tengfei Song ◽  
Qian Zhang ◽  
Lixin Yang ◽  
...  
Keyword(s):  
Analytical Model ◽  
End Effects ◽  
Linear Induction ◽  
One Dimensional ◽  
Electromagnetic Pump ◽  
Electromagnetic Pressure ◽  
Pressure Characteristics

A Hybrid FEM-Analytical Force and Torque Model for the Electrodynamic Suspension Reaction Sphere

2017 ◽  
Author(s):  
Anlin Chen ◽  
Ming Zhang ◽  
Yu Zhu ◽  
Zhouyu Huai ◽  
Kaiming Yang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Analytical Model ◽  
Attitude Control ◽  
Magnetic Vector Potential ◽  
Attitude Control System ◽  
End Effects ◽  
Fem Simulations ◽  
Linear Induction ◽  
Electrodynamic Suspension ◽  
The Magnetic Field

The actuator of attitude control system (ACS) is a significant component of the spacecraft. The electrodynamic suspension reaction sphere (EDSRS) is a compact and lightweight actuator of ACS and can control spacecraft attitude in three axes. This paper presents a hybrid FEM-analytical force and torque model for the EDSRS. A motor in the EDSRS is divided into many circular rings which are unfolded along circumference and equivalent to linear induction motors. The magnetic field in each equivalent linear induction motor (ELIM) is derived by the two-dimensional magnetic vector potential method. Based on the magnetic field, the force on the mover of each ELIM is obtained by Maxwell stress tensor method. An analytical force and torque model of the EDSRS is developed according to the force of every ELIM. Furthermore, the errors between the analytical model and three-dimensional FEM simulations are analyzed. With FEM simulations, new correction factors which take the end effects into consideration are obtained. The analytical model is further developed to a hybrid FEM-analytical force and torque model which includes the end effects. Finally, the hybrid FEM-analytical model is verified by FEM simulations and experiments.

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

Electronics ◽  
2021 ◽  
Vol 10 (14) ◽  
pp. 1644
Author(s):  
Qian Zhang ◽  
Huijuan Liu ◽  
Tengfei Song ◽  
Zhenyang Zhang
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Equivalent Circuit ◽  
Skin Effect ◽  
Equivalent Circuit Model ◽  
Element Model ◽  
Circuit Model ◽  
End Effects ◽  
3D Finite Element ◽  
Linear Induction

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.

Polar Optical Phonon Instability and Intervalley Transfer in Gallium Nitride

1998 ◽  
Vol 512 ◽  
Author(s):  
B. E. Foutz ◽  
S. K. O'leary ◽  
M. S. Shur ◽  
L. F. Eastman ◽  
B. L. Gelmont ◽  
...  
Keyword(s):  
Gallium Nitride ◽  
Analytical Model ◽  
Optical Phonon ◽  
Room Temperature ◽  
Phonon Scattering ◽  
Polar Optical Phonon ◽  
Scattering Mechanism ◽  
Loss Mechanism ◽  
One Dimensional ◽  
Optical Phonon Scattering

ABSTRACTWe develop a simple, one-dimensional, analytical model, which describes electron transport in gallium nitride. We focus on the polar optical phonon scattering mechanism, as this is the dominant energy loss mechanism at room temperature. Equating the power gained from the field with that lost through scattering, we demonstrate that beyond a critical electric field, 114 kV/cm at T = 300 K, the power gained from the field exceeds that lost due to polar optical phonon scattering. This polar optical phonon instability leads to a dramatic increase in the electron energy, this being responsible for the onset of intervalley transitions. The predictions of our analytical model are compared with those of Monte Carlo simulations, and are found to be in satisfactory agreement.

scholarly journals Improved Model-Free Adaptive Sliding-Mode-Constrained Control for Linear Induction Motor considering End Effects

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Xiaoqi Song ◽  
Dezhi Xu ◽  
Weilin Yang ◽  
Yan Xia ◽  
Bin Jiang
Keyword(s):  
Control Method ◽  
Sliding Mode ◽  
Dynamic Performance ◽  
Research Field ◽  
Constrained Control ◽  
End Effects ◽  
Linear Induction ◽  
Adaptive Sliding Mode ◽  
Model Free ◽  
Improved Model

As a kind of special motors, linear induction motors (LIM) have been an important research field for researchers. However, it gives a great velocity control challenge due to the complex nonlinearity, high coupling, and unique end effects. In this article, an improved model-free adaptive sliding-mode-constrained control method is proposed to deal with this problem dispensing with internal parameters of the LIM. Firstly, an improved compact form dynamic linearization (CFDL) technique is used to simplify the LIM plant. Besides, an antiwindup compensator is applied to handle the problem of the actuator under saturations in case during the controller design. Furthermore, the stability of the closed system is proved by Lyapunov stability method theoretically. Finally, simulation results are given to demonstrate that the proposed controller has excellent dynamic performance and stronger robustness compared with traditional PID controller.

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