Electromagnetic Shunt Research Articles

Design and test of a contactless damper for HTS maglev systems via electromagnetic shunt dampers

High-temperature superconducting (HTS) maglev system is promising to become the future high-speed transport due to its numerous advantages. However, the low-damping dynamic characteristics of superconductors make the system vulnerable to external disturbances, which present a significant challenge to its implementation. To enhance the vibration attenuation effect of the HTS maglev system, a non-contact damper that employs electromagnetic shunt damping (EMSD) and negative resistance is incorporated into the HTS maglev system. This study elucidates the principles of EMSD and negative resistance, and establishes the governing equations to describe the behavior of the HTS maglev model equipped with EMSD. Subsequently, the EMSD coupling coefficients are analysed via the finite element method (FEM) under varying conditions. Finally, a dedicated vibration test rig is designed and fabricated to validate the effectiveness of the proposed damper. The results demonstrate that the proposed damper, in combination with negative resistance, is capable of effectively suppressing vibration in HTS maglev systems. The maximum acceleration of the test model can be reduced by 86% compared with the original system without the damper. This work may provide valuable guidance for future practical implementations.

Vibration control by using active electromagnetic shunt damper

It is well-known that the traditional electromagnetic shunt damping (EMSD) techniques are limited by the damping force of electronic components and require a negative resistance (NR) shunt circuit to enhance performance. However, the NR shunt circuit could lead to the EMSD system being unstable. Addressing this, this study proposes an advanced control system that employs active control technology combined with EMSD for vibration control. We first developed a dimensionless mathematical model of the control system, which was then finely tuned using an adaptive simulated annealing particle swarm optimization algorithm. Subsequently, the relationship between control gain and optimal shunt circuit parameters was predicted using a BP neural network. Finally, the proposed Active-EMSD (AEMSD) was experimentally verified. The experimental results demonstrate that the proposed AEMSD not only surpasses traditional thresholds but also excels in isolating low-frequency vibrations. Compared to traditional EMSD, the proposed AEMSD showed improved effectiveness.

Ultra-Low Frequency Vibration Isolation of Cockroach-Inspired Structures With Electromagnetic Shunt Damping Enhanced by Geometric Nonlinearity

Ultra-Low Frequency Vibration Isolation of Cockroach-Inspired Structures With Electromagnetic Shunt Damping Enhanced by Geometric Nonlinearity

Vibration Suppression of Superconducting Magnetic Levitation System by LCR Parallel Electromagnetic Shunt Damper

Vibration Suppression of Superconducting Magnetic Levitation System by LCR Parallel Electromagnetic Shunt Damper

Multi-objective parameter optimization of electromagnetic shunt damper for high-Temperature superconducting maglev vehicle system

High-temperature superconducting pinning maglev technology has great potential for high-speed transportation due to its passive stability and friction-free characteristics. However, at high speeds, the weak damping characteristics of the system make it challenging to attenuate system vibrations caused by external excitation effectively. An electromagnetic shunt damper can be added to the high-temperature superconducting vehicle system to address this challenge. However, due to the complexity of the high-temperature superconducting vehicle system and external excitation, it is challenging to determine the optimal electromagnetic shunt damper parameters through analytical calculation. This study proposes a method for optimizing electromagnetic shunt damper parameters based on the NSGA-II multi-objective optimization algorithm. The high-temperature superconducting vehicle dynamic simulation model with electromagnetic shunt damper is established, and the dynamic simulation is carried out according to the actual operation conditions. Taking the dynamic indexes as the objectives, the optimal electromagnetic shunt damper parameters are then selected within a reasonable range based on dynamic indexes used as objectives in the NSGA-II algorithm. The effectiveness of the optimization method is verified through simulations and experiments on a levitation model vehicle with electromagnetic shunt damper under random vibration conditions. Finally, the optimized electromagnetic shunt damper parameters are applied to an engineering high-speed high-temperature superconducting pinning maglev vehicle through simulation. The calculation results demonstrate that various performance indexes are improved after optimization. This optimization design provides a reference for applying electromagnetic shunt damper in high-temperature superconducting pinning maglev vehicles.

Dual-Functional Energy Harvesting and Low-Frequency Vibration Attenuation: Electromagnetic Resonant Shunt Series Quasi-Zero-Stiffness Isolators

In recent times, there has been a significant focus on electromagnetic resonant shunt damping (ERSD) and quasi-zero-stiffness vibration isolators (QZS VI) as prominent solutions for vibration mitigation or energy harvesting. In this paper, an innovative retrofittable model is proposed for dual-functional energy harvesting and low-frequency vibration attenuation by combining the ERSD and two-stage quasi-zero-stiffness vibration isolator (TQZS VI). The viscous dissipative element between the TQZS VI upper and lower layers is implemented using an electromagnetic shunt transducer that is connected in parallel with a resonant RLC (resistor–inductor–capacitor) circuit. Firstly, the mathematical model of the electromagnetic resonant shunt series quasi-zero-stiffness isolator (ERS-TQZS VI) is developed. Then, the magnitude-frequency response equations of the ERS-TQZS VI system are approximately solved using the harmonic balance method (HBM) in combination with the pseudo-arc-length method (PLM). The analytical approach is validated using numerical simulations. Moreover, the force transmissibility and output power of the ERS-TQZS VI are defined, and detailed parametric analysis for energy harvesting and low-frequency vibration attenuation is performed to assess the critical design parameters that result in optimal performance of the ERS-TQZS VI. The results demonstrate that the ERS-TQZS VI exhibits a significant reduction in resonance peaks of low-frequency vibration while simultaneously enabling effective vibration energy harvesting.

Vibration control of flexible rotors using a passive magnetic device working on the principle of electromagnetic shunt damping

Excessive rotor vibration can propagate the micro-cracks and hence the premature failure of the rotor system. A passive magnetic device working on the principle of electromagnetic shunt damping (EMSD) is proposed to passively control the rotor vibrations. Although, these EMSD-based damping systems are quite common in the literature, however, there is not even a single article available in the literature, showing the application of such a device passively controlling the rotor vibrations from a distance. Due to the flow of flux between the rotor, stator, and air gap, the modeling procedure for such an EMSD-based system changes completely and is not available in the literature. Due to rotor movement, there is a variation in the magnetic flux provided by the permanent magnets placed in the device. Due to electromagnetic interactions, electric currents are induced in the windings provided in the device. When these currents are allowed to pass through electrical resistance, damping forces are generated. In this way, vibration energy is converted into heat energy. In this research, it is observed that the damping effect is maximum for an optimal value of electrical resistance. The effect of several turns in the windings and permanent magnet thickness is also investigated in terms of the production of damping forces. The efficiency of the device is mathematically proved through simulations. Further, experimental results verify the effectiveness of the proposed device.

Research on isolation method of spacecraft reaction wheels using electromagnetic shunt damping

The spacecraft flywheel system is widely used in various space missions due to its cleanliness, high reliability and high control accuracy, such as spacecraft attitude control and large-angle turning maneuvers. However, current research agrees that the high-speed rotating flywheel system is one of the main sources of micro-vibration disturbances on spacecraft. In view of the variable speed characteristics of the flywheel, this paper proposes a new vibration isolation system based on Stewart vibration isolation platform and electromagnetic shunt damping (EMSD). Attempts to connect three circuits of pure resistance circuit, resistance-inductance circuit and resistance-inductance-capacitor circuit to the new vibration isolation system in order to improve the isolation performance. Through theoretical analysis and numerical simulation, the effect of circuit parameters on isolation performance of each circuit are studied. The results show that EMSD can significantly reduce the disturbance input of the flywheel, and frequency modulation can be achieved through the conversion circuit to avoid resonance.

Investigation on high‐order resonant electromagnetic shunt dampers for vibration control: Methodology and optimum tuning

Investigation on high‐order resonant electromagnetic shunt dampers for vibration control: Methodology and optimum tuning

Vibration Suppression of HTS Maglev System Based on Negative Resistance Electromagnetic Shunt Damper

The high-temperature superconducting (HTS) maglev system has tremendous possibilities for future high-speed transportation application owing to its salient advantages of self-stable levitation and zero pollution operation. However, previous study indicated that the relatively low damping of HTS system may lead the undesired large-amplitude nonlinear vibration in system. Thus, electromagnetic shunt damper (EMSD), which usually consists of electromagnets, permanent magnets and shunt impedance connected to the terminals of the coils, is introduced in the system to improve the damping of the system. The effect of EMSD is to transfer the mechanical energy to electrical energy and consume it in the form of Joule heat. For better vibration suppression performance, this paper proposes a negative resistance electromagnetic shunt damper (NR-EMSD) in HTS maglev vehicle model. The negative resistance can offset the inherent resistance of the electromagnet coils and as a consequence, the induced current of the circuit will increase as well as the induced electromagnetic force. Also, the change of total resistance of the circuit will influence the vibration reduction performance. In this paper, the effect of NR-EMSD is tested by experiment under different working conditions compared with the model without EMSD. The results are analyzed and basic conclusions are summarized. This work may provide references for further practical application in HTS system.

Vibration suppression of floating offshore wind turbines using electromagnetic shunt tuned mass damper

This paper investigates the suppression of in-plane vibrations of a floating offshore wind turbine (FOWT) using the electromagnetic shunt tuned mass damper (EMSTMD), where the dashpot is replaced by a shunted electromagnetic (EM) transducer for improving performance and durability of the damper. A series resistive–capacitative–inductive (RCL) network is designed as the supplemental shunt for the EM transducer, which results in an additional resonance for performance improvement. A 17-degree-of-freedom (17-DOF) aero-hydro-servo-elastic model is established for the FOWT, which is used for performance evaluation of the EMSTMD in the time domain. A reduced-order 6-DOF model is then developed for the FOWT in-plane vibrations with EMSTMD mounted, accounting for rotor mass moment of inertia, stiffness from buoyancy and mooring lines, as well as hydrodynamic added mass. This model facilitates an efficient frequency-domain optimization procedure for the EMSTMD, taking into account uncertainties in the environmental conditions. The performance of the optimized EMSTMD is compared with that of the classic TMD in both frequency and time domains. It is shown that both EMSTMD and TMD effectively reduce tower side–side vibrations of FOWT, and also have lightly positive effect on the spar roll and blade edgewise vibrations. EMSTMD consistently outperforms TMD for all environmental conditions, at the cost of slightly increased absorber stroke.

Characterization of LCR Parallel-Type Electromagnetic Shunt Damper for Superconducting Magnetic Levitation

This study investigated the effect of electromagnetic shunt dampers on the resonance amplitude reduction in a superconducting magnetic levitation system. There are two types of electromagnetic shunt dampers, series type and parallel type, depending on the configuration of the electric circuit, and their damping characteristics may differ depending on the external resistance value in the circuit. In this study, after discussing the vibration-suppression effects of both types according to the governing equations, vibration experiments were conducted using both dampers with different resistance values. As a result, it was confirmed that, for the larger resistance value, the amplitude reduction effect is smaller in the series-type damper, while it remained high in the parallel type. We also performed numerical integrations, including the nonlinearity of magnetic force in the superconducting magnetic levitation system. As a result, it was numerically confirmed that the parallel-type damper can also be expected to reduce amplitude at a resonance caused by nonlinearity.

Bi-objective optimal design of an electromagnetic shunt damper for energy harvesting and vibration control

Owing to the electromechanical energy conversion capacity, electromagnetic shunt dampers (EMSDs) are widely applied to vibration suppression or energy harvesting from vibrating structures. Either one of the two functions can be optimized in the designs of EMSD found in the literature. In this paper, a bi-objective optimization methodology of EMSD is proposed for the simultaneous maximization of energy harvesting from the damper and the suppression of resonant vibration of a dynamic structure. An EMSD with opposing magnet pairs configuration is designed to achieve the two design objectives simultaneously in a single-degree-of-freedom (SDOF) system and a dynamic vibration absorber (DVA). It is proved analytically and experimentally that maximum energy can be harvested by the EMSD when its internal impedance equals to the external electrical resistance of the electrical circuit. Minimum resonant vibration amplitude of the primary mass can be achieved at the same resistance ratio in the DVA system by selecting the suitable number of opposing magnet pairs of the EMSD without affecting the internal resistance. An EMSD with opposing magnet pairs configuration is designed and tested in a single-degree-of-freedom (SDOF) system and a dynamic vibration absorber. Following a proper procedure, the electromechanical transduction factor of the proposed EMSD can be tuned to achieve both objectives simultaneously. The harvested energy is higher when the EMSD is deployed in the SDOF system than in the DVA system, but the frequency bandwidth for energy harvesting is much wider in the DVA system. Analyses lead to a design guideline of the EMSD for achieving the bi-objective optimization.

Hybrid electromagnetic shunt damper with Coulomb friction and negative impedance converter

Electromagnetic shunt damper (EMSD) offers flexible tunability of linear damping. The low damping force-to-mass ratio of the EMSD, however, hinders those applications which require large damping force. Adding a negative impedance shunt in EMSD circuit can increase its damping force and broaden its effective frequency range at the expense of causing possible instabilities in the control circuit. On the other hand, Coulomb friction damper (FD) can offer a higher damping force-to-mass ratio than EMSD but it is difficult to be precisely controlled due to its nonlinear characteristics and excessive frequency sensitivity. This paper examines, both theoretically and experimentally, two types of hybrid dampers: one combining an EMSD and a Coulomb friction damper (EMSD+FD), and the other EMSD with a voltage negative impedance converter (EMSD+VNIC). Through proper control of the additional damping arising from FD and VNIC, the problem of unstable ESMD+VNIC and the excessive frequency sensitivity of the FD are alleviated. A prototype of EMSD+VNIC+FD is built and tested. The damping force provided by the FD in the prototype is varied by adjusting the normal force applied by a compression spring, while that from the EMSD+VNIC is controlled by adjusting the shunt circuit impedance with a variable resistor. The maximized tunability of the two enhancement methods provides a ninefold increase of the tunable damping range and a sixfold increase of the damping force-to-mass ratio of the EMSD. The proposed EMSD+VNIC+FD is finally applied and tested experimentally to achieve H∞ optimization of a ground-hooked dynamic vibration absorber for the minimization of resonant vibration of a single-degree-of-freedom system.

Lever-type high-static-low-dynamic-stiffness vibration isolator with electromagnetic shunt damping

Owing to the ultra-low frequency vibration isolation performance without compromising static stiffness, high-static-low-dynamic-stiffness (HSLDS) vibration isolators (VIs) have advantages over linear vibration isolators. This paper presents a lever-type HSLDS vibration isolator (L-HSLDS-VI) by employing negative resistance electromagnetic shunt damping (EMSD) together with eddy current damping to eliminate the jump phenomenon and thus to improve the stability of L-HSLDS-VIs. The lever inerter system can amplify the mass effect to broaden the isolation band. The theoretical model of L-HSLDS-VIs with EMSD (L-HSLDS-VI-EMSD) was established. The effects of negative resistance and lever ratio on the vibration isolation performance of L-HSLDS-VI-EMSD were investigated analytically and experimentally. The L-HSLDS-VI can provide significant nonlinear stiffness, which can realize the quasi-zero stiffness (QZS), and thus broaden the isolation band. EMSD produces a considerable damping effect to enhance the vibration mitigation performance of L-HSLDS-VI. The combination of the EMSD and nonlinear ECD damping is an efficient approach to improve the vibration isolation performance to overcome the jump phenomenon. This paper utilizes the lever effect to amplify damping effects, which could provide a guideline to modify the performance of HSLDS-VIs.

Optimal design of a tunable electromagnetic shunt damper for dynamic vibration absorber

Dynamic vibration absorber (DVA) is an effective device for suppressing resonant vibration of noisy machineries and structures. However, the optimum design of DVA requires precise tuning of the damping force in the DVA, which unfortunately is often not practical and prone to changes of working conditions. In this paper, a tunable electromagnetic shunt damper (EMSD) with different opposing magnet pairs configurations is tested for the optimum design of DVA. The optimum magnet pairs configuration is derived to provide the maximum damping force in the DVA. Both simulations and experiments are conducted to verify the damping coefficient variation with the number of magnet pairs in the EMSD. The experimental optimization procedure of the DVA is designed according to the fixed-points theory. The damping force generated by the EMSD can be readily adjusted by varying the external resistance of the EMSD. This is the first experimental implementation report of the optimization procedure described in the fixed-points theory. The proposed tunable EMSD can conveniently allow for onsite optimal tuning of DVA. The proposed design methodology provides fine tuning of the damping coefficient of EMSD to achieve robust optimal DVA performance, even when subject to changes of external parasitic damping.

Theoretical optimization and experimental verification of a non-contact damper for high temperature superconducting Maglev systems

High-temperature superconducting (HTS) maglev has excellent potential in high-speed transportation due to its capability of passive stabilization levitation. However, in applications, the vibration of maglev vehicle with a large amplitude will be triggered for some external incentives or interference owing to its weak damping characteristics. Hence, it is preferable and necessary to find a way to reduce the vibration without mechanical contact. In terms of mechanical structure, the HTS maglev system mainly consists of HTS bulks and permanent magnets guideway (PMG). Utilizing the magnetic field provided by PMG, we designed and assessed an electromagnetic shunt damper (EMSD) for the HTS maglev system, by which the vibrations can be attenuated without contact. At first, the parameters of EMSD were theoretically optimized, respectively. Second, according to the structure of the Halbach PMG, the experimental EMSD was presented. In this damper, two groups of coils in reverse series were set above the two magnetic poles of the PMG to get a large induced electromotive force. Eventually, the experimental results show that the vibrations of the HTS maglev model vehicle can be attenuated more than 80% in the resonance region when the designed EMSD was employed in the system. Namely, this non-contacting damper will highly enhance the dynamic characteristics of HTS maglev systems.

A tunable hybrid damper with Coulomb friction and electromagnetic shunt damping

Vibration dampers with tunable properties are of practical significance to accommodate the need of vibration control under different circumstances. Among major parameters, tunable damping to deliver required accuracy within a given frequency range is difficult to achieve in practice. This paper proposes a hybrid tunable damper by combining the advantages of both Coulomb friction damping and electromagnetic shunt damping. The tunable friction damper (FD) allows for coarse tuning with a larger tunable range, while the tunable electromagnetic shunt damper (EMSD) functions as a fine tuner with fine precision. The end result is a significantly increased tunable frequency range with high precision. The proposed method allows for simple and low cost adjustment of the damping forces in both dampers. A prototype is fabricated and experimentally tested in a dynamic vibration absorber (DVA) system. The predicted tenability is experimentally verified and H∞ optimal damping of the DVA is readily achieved by using the proposed hybrid damper.

Enhanced lever-type vibration isolator via electromagnetic shunt damping

Considering the damping limitation of traditional lever-type vibration isolators (LVIs) in the low-frequency range, electromagnetic shunt damping (EMSD) utilising a lever to amplify the damping force is introduced in this study to improve the vibration isolation performance of LVIs. Negative resistance (NR) and NR resonant shunts were used to compensate for inherent resistance to improve the effect of LVI with EMSD (LVI-EMSD). A theoretical model of LVI-EMSD was established, and displacement transmissibility was derived. The optimal parameters of the NR resonant shunt were derived according to the fixed-point theorem. The effects of the lever ratio, negative resistance, and resonant frequency of the circuit on the vibration isolation performance of the LVI-EMSD were numerically and experimentally analysed. The lever structure can simultaneously tune the natural frequency and damping to improve the vibration isolation performance of the LVI-EMSD. Both the NR and NR resonant shunts effectively produce a considerable damping effect, and the NR resonant shunt outperforms the NR shunt in the low-frequency region. The NR shunt could produce a mass effect when the negative resistance was carefully designed. This study provides guidelines for the design, modelling, and optimisation of LVI-EMSD.

LCR並列型電磁シャントダンパを有する超電導磁気浮上系の非古典的モード解析

LCR並列型電磁シャントダンパを有する超電導磁気浮上系の非古典的モード解析