International Journal of Applied Electromagnetics and Mechanics - Volume 62, issue 2

Authors: Liu, Qing | Wang, Li | Zhang, Shiping | Wang, Xinjie | Yu, Chengyu | Lei, Gang

Article Type: Research Article

Abstract: Based on the non-contact characteristics, active magnetic bearings (AMBs) possess great benefits like no lubrication, high speed, high accuracy and long lifespan. Moreover, the rotor dynamic performance is adjustable and working conditions are monitorable. Nonetheless, AMBs suffer from large power loss and rotor heating. One viable approach is omitting the bias current, i.e., zero-bias AMBs, but this also results in high non-linearity and poor controllability. The common control practices of zero-bias AMBs are based on nonlinear models, for there is only one electromagnet being electrified at any moment to produce a net control force. In this study, we propose a …linear control strategy for the zero-bias AMB. Assuming that each coil has an average current proportional to the pulse width modulation (PWM) duty cycle, the quantitative relation among the magnetic force, the rotor displacement and the coil current can be acquired. Further, this control algorithm was applied to both the horizontal and the vertical thrust zero-bias AMBs. Experimental results proved the existence of currents in both electromagnetic bearings in the unbalanced state. And the rotor-bearing system restored rapidly to an equilibrium state after sudden disturbances. Overall, this method demonstrates the transition from physics to engineering and shows a good application prospect. Show more

Keywords: Zero-bias magnetic bearing, mathematical model, quantitative control, PWM, power consumption

DOI: 10.3233/JAE-180127

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 62, no. 2, pp. 221-242, 2020

Authors: Wu, Jie | Hu, Hong | Liang, Jian

Article Type: Research Article

Abstract: This paper investigates the magnetic circuit model of a multi-pole multi-layer magnetorheological (MR) brake. Firstly, a simple introduction to the structure is given. This MR brake has a unique structure design with several MR fluid working gaps set between two-layer coils. Then, magnetic circuit model is conducted to theoretically approximate the effects of the design parameters on the magnetic field strength within the MR fluids. According to the magnetic circuit analysis, a parametric study is performed to optimize the critical design parameters of the magnetic circuit of the designed brake. Finally, the magnetic circuit model is validated based on the …optimized structure and simulation. Simulation results indicate that the magnetic circuit model is feasible to estimate the magnetic field strength in the working gaps, and it can be used to guide the parameters optimization and structure design. Show more

Keywords: Magnetorheological (MR) brake, magnetic circuit, modeling, finite element analysis, optimization

DOI: 10.3233/JAE-190025

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 62, no. 2, pp. 243-266, 2020

Authors: Shi, Yan | Lin, Cong | Lu, Bin

Article Type: Research Article

Abstract: Electromagnetic linear actuator (EMLA) is an alternative of the conventional damper in vehicle suspensions and harvests suspensions vibration energy which is wasted generally. Due to large variations of its Back Electromotive Force (Back-EMF), it will thus be interest to investigate how to recycle the electricity efficiently. In this paper, to improve the recycling efficiency of the EMLA, a feedback energy circuit featured with combination of parallel switchover supercapacitors technology and a boost-buck DC-DC converter is proposed on the basis of the generating characteristics of a newly designed EMLA. By modeling the feedback energy circuit, its dynamic characteristics are simulated and …its efficiency is investigated. The results of simulations and experiments show that the feedback energy circuit can achieve a wide range of energy recovery regardless of large variations of Back-EMF induced by the EMLA. Simultaneously, by keeping the boost-buck ratio less than 3, the efficiency of energy recovery is high, in some cases could reach 94%. Show more

Keywords: Energy harvesting, electromagnetic linear actuator, active suspensions, feedback energy circuit

DOI: 10.3233/JAE-180135

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 62, no. 2, pp. 267-281, 2020

Authors: Liu, Yafeng | Wang, Xinjie | Wang, Jiong | Chen, Hejuan

Article Type: Research Article

Abstract: The lanthanum-doped lead zirconate titannate (PLZT) ceramic has shown its potential applications as light-controlled micro actuators activated by ultraviolet light for the photovoltaic effect in the field of micro-driven. Aiming to the slow response of photostriction of PLZT ceramic, the primary purpose of this article is to propose a light-controlled actuator with the novel opto-electrostatic hybrid driving based on PLZT ceramic. The mathematical model of the proposed light-controlled actuator is established on basis of the anomalous photovoltaic effect model of PLZT ceramic. The actuation characteristics of the micro actuator are investigated based on the established mathematical model and the experiments …of the photovoltage of PLZT ceramic. Furthermore, the actuation curves of the micro actuator driven by opto-electrostatic hybrid driving based on PLZT ceramic are acquired to verify the rationality and feasibility of the light-controlled micro actuator design. So according to the analysis and experimental results, the light-controlled actuator driven by the novel opto-electrostatic hybrid driving based on PLZT can conduct the effectively and precisely displacement control with fast response speed. In addition, the driving method based on the novel opto-electrostatic hybrid driving has advantages of non-contact control, remote control and no electromagnetic interference, etc. Show more

Keywords: PLZT, micro actuator, opto-electrostatic hybrid driving, light-controlled

DOI: 10.3233/JAE-190035

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 62, no. 2, pp. 283-294, 2020

Authors: Li, Zhao | Yan, Li | Qu, Boyang | Fu, Kai

Article Type: Research Article

Abstract: In this paper, an analytical model is proposed to predict the magnetic field and torque characteristics of flux-concentration cage-type eddy-current couplings with slotted conductor rotor topology. Due to the presence of discontinuous boundary conditions in permanent magnet rotor domain and conductor rotor domain, the accurate sub-domain method is employed in polar coordinates. The permanent magnet domain and the conductor domain are divided into different sub-domain according to the number of poles and slots. The magnetic vector potential in each domain is obtained by solving the field equation based on the separated variable method. Then the magnetic field distributions and output …torque are computed. By using the nonlinear 2D and 3D finite element analysis, the validity of such model is proved, and the cause of deviation is discussed. In the end, the proposed formula is used for a design optimization using particle swarm optimization algorithm. Show more

Keywords: Eddy-current couplings, sub-domain method, finite-element method, design optimization

DOI: 10.3233/JAE-190056

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 62, no. 2, pp. 295-313, 2020

Authors: Zhang, Yuyang | Leng, Yonggang

Article Type: Research Article

Abstract: Magnets are widely used in many fields, both industry and our daily life, because of their unique properties such as non-contact interactions and electricity generation. However, behaviors of permanent magnets seem to deviate from our basic understanding that opposite poles attract and like poles repel. We have recently discovered an interesting phenomenon in pairs of permanent magnets with large different sizes where the like poles do not seem to repel and the unlike poles do not seem to attract with each other, due to a localized area with reversed pole existing in the large permanent magnet. In this paper, we …first experimentally confirm the existence of this particular phenomenon by studying interactions of several groups of permanent magnets with different sizes, then we introduce the property of the irreversible movements of load line and working point of permanent magnet to figure out this transition process from repulsion to attraction between a pair of permanent magnets with large different sizes. A reasonable explanation is finally given. In the end, we suggest a few applications for this special phenomenon. Show more

Keywords: Magnetic force calculation, load line, demagnetizing field, working point

DOI: 10.3233/JAE-190057

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 62, no. 2, pp. 315-329, 2020

Authors: Mingliang, Zheng

Article Type: Research Article

Abstract: In this paper, the Lie symmetry theory of singular mechanico-electrical coupling systems is studied in phase space. Firstly, the Hamilton canonical equation of singular mechanico-electrical coupling systems is established through energy; Secondly, considering the inherent constraints brought by singularity, the determining equations, definitions, structural equations and conserved quantities of Lie symmetry are all given; Finally, an application example is given. It is shown that if the structural equation of Lie symmetry is just right the criterion equation for Noether symmetry, then the Lie symmetry can lead to the conserved quantity of Noether type; if the structural equation of Lie symmetry …does not involve the Hamiltonian function, the conserved quantity of non-Noether type can be obtained only through finding the invariant of symmetric group. Show more

Keywords: Singular mechanico-electrical coupling systems, Lie symmetries, structural equations, conserved quantities

DOI: 10.3233/JAE-190059

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 62, no. 2, pp. 331-339, 2020

Authors: Gong, Qi | Zhang, Weiwei | Su, Yufeng | Zhang, Kun

Article Type: Research Article

Abstract: In this paper, a diamagnetic-airflow hybrid levitation structure is reported, with a floating magnet rotor stably levitated above a diamagnetic disc just using a lifting magnet and airflow. Compared with the typical diamagnetically stabilized structure, the rotation speed of the rotor is increased from 9570 rpm to 16666 rpm, and the levitation gap is increased from 0.3 mm to 0.7 mm when the airflow rate exceeds 2198 sccm under standard temperature and pressure (STP). At the same time, the rotor can be stably levitated at any height from 0.2 mm to 0.8 mm by adjusting the vertical position of the nozzles. With the hybrid levitation structure, it’s …possible to overcome the structural limitation of typical diamagnetically stabilized levitation structure and enhance the working performance of the rotor. This levitation structure is expected to be applied to sensing, energy harvesting and air bearing under actuation of airflow. Show more

Keywords: Diamagnetic, airflow, stabilized levitation, simulation, energy harvesting

DOI: 10.3233/JAE-190081

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 62, no. 2, pp. 341-354, 2020

Authors: Lin, Chih-Hong | Chang, Kuo-Tsai

Article Type: Research Article

Abstract: Compared with the classical linear controller, the nonlinear controller can result better control performance for the nonlinear uncertainties of the continuously variable transmission (CVT) system which is driven by the synchronous reluctance motor (SynRM). The better control performance can be shown in the nonlinear uncertainties behavior of CVT system by using the proposed novel admixed improved recurrent Hermite polynomial neural network (AIRHPNN) control system. The novel AIRRHPNN control system can carry out overlooker control, improved recurrent Hermite polynomial neural network control (IRHPNN) with an adaptive law, and reimbursed control with an appraised law. Additionally, according to the Lyapunov stability theorem, …the adaptive law in the IRHPNN and the appraised law of the eimbursed controller are established. Furthermore, two weights with two varied learning rates according to increment Lyapunov function are derived to help improving convergence. Finally, comparative examples are illustrated by the experimental results to confirm that the proposed control system could be obtained better control performance. Show more

Keywords: Continuously variable transmission, Lyapunov stability, recurrent Hermite polynomial neural network, synchronous reluctance motor

DOI: 10.3233/JAE-180079

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 62, no. 2, pp. 355-382, 2020

Authors: Xing, Jichun | Ren, Wendi | Qin, Yong

Article Type: Research Article

Abstract: For a non-contact piezoelectric motor modulated by an electromagnetic field, the design scheme of a piezoelectric micro-displacement amplifying mechanism is described. The relation formula between the output displacement of piezoelectric stacks and the output angle of the mechanism are given. Using the theory of electromagnetism, the static output torque equation of electromagnetic coupling mechanism based on the output angle of the piezoelectric amplifying mechanism is established, and the effect of system parameters on the static output moment is analyzed. Considering this piezoelectric motor driven by a square wave signal, the dynamic output torque equation of the non-contact piezoelectric motor is …established, and the effect of system design parameters on the dynamic output torque is revealed. The analysis results show that the different output step precisions of the piezoelectric motor can be obtained by adjusting the length of the bar 1. A reasonably selected output angle is beneficial to increase electromagnetic torque. When the air gap is reduced to improve the torque, a larger output torque can be obtained by designing a reasonable output angle. At a certain amplitude of modulation voltage, the reasonable combination of external resistance and modulation signal frequency is beneficial to the design of an ideal dynamic torque response waveform and larger dynamic torque amplitude. The above analysis results can lay a theoretical foundation for the design of a high-performance non-contact piezoelectric motor modulated by electromagnetic and the optimization of the drive scheme. Show more

Keywords: Electromagnetic torque, non-contact, modulated by an electromagnetic field, flexure hinge mechanism

DOI: 10.3233/JAE-180116

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 62, no. 2, pp. 383-401, 2020