Magnetic Coupling System Research Articles

High misalignment-tolerant wireless charging magnetic coupling system with combined pickups for UAVs

High misalignment-tolerant wireless charging magnetic coupling system with combined pickups for UAVs

Motion analysis of and experimental research on a magnetic and elastic coupling oscillation system

To analyze the motion laws of a magnetic and elastic coupling system under the influence of various factors, this paper proposes a magnetic coupling pendulum based on spring pieces and magnets—a magnetic–mechanical oscillator. By fixing spring pieces onto two non-magnetic bases and attaching magnets to their upper ends, which repel each other, the potential energy during oscillation is expanded using Fourier series. Subsequently, Lagrange equations are solved to study the effects of the first two terms of potential energy. spring piece Using algebraic simplification and transformation, as well as model experiments, its dynamic behaviors, such as its motion frequency and phase characteristics, were explored according to different influencing factors, including the magnetic potential energy, the elastic modulus of the spring, and the external environment. We analyzed the impact of the simplified system's main parameters on its vibration modes, deriving the model formulas and the experimental results. The conclusions from the formula derivation indicate that the motion frequency of the simplified system is a superposition of two frequency. Under certain conditions, these frequencies can be separated, simplifying the system's dynamics. Equally, the experimental results corroborated the findings from the formula derivation, providing a reference for the design and study of dynamic behaviors in magnetic coupling systems.

Pendulum type magnetically coupled rotary piezoelectric energy harvester

This research proposes a rotary motion-based non-contact pendulum piezoelectric energy harvester (P-PEH). The working region of the piezoelectric vibrator can be maintained in a magnetically coupled system at all times by means of a motion conversion mechanism. The combination of the motion conversion mechanism and the magnetic coupling system not only reduces the loss of the piezoelectric material, but also improves the output performance of the piezoelectric vibrator. The paper investigates the effects of the excitation distance L, the radius of the base circle R, and the number of excitation magnets N on the output performance of the P-PEH. When the input speed of 600 rpm, L = 10 mm, R = 21 mm, and N = 1, the peak-to-peak voltage (Vpp ) is 58.75 V. At this parameter, the output power of the device with an external 20 kΩ load is 0.0187 W. The viability of P-PEH was finally demonstrated through several application testing. P-PEH can easily light up 63 LEDs while its output energy can keep the temperature and humidity sensor in use. In summary, P-PEH can effectively collect external rotational energy for power storage and supply, and supply electricity to wireless sensor networks and microelectronic devices with further studies.

A Novel Magnetic Coupled Railgun System Based on Inductive Pulsed Power Supply—Preliminary Theoretical Analysis and Experiment Study

A Novel Magnetic Coupled Railgun System Based on Inductive Pulsed Power Supply—Preliminary Theoretical Analysis and Experiment Study

Comparative Analysis of SS, SP, PP and PS Topologies for Magnetic Coupled Wireless Power Transfer System Composed of the Negative Resistor

In recent years, the concept of the negative resistor (NR) has been proposed and applied in the magnetic coupled wireless power transfer (MC-WPT) system to improve the stability of power transfer. However, it remains a fundamental challenge to find the characteristic differences and applications of the four basic NR-based MC-WPT topologies. In this paper, the circuit models of the four basic NR-based MC-WPT topologies: series-series (SS), series-parallel (SP), parallel-parallel (PP), and parallel-series (PS) are established, and their characteristics are analyzed and compared by using circuit theory, which enables engineers to determine and select topologies to suit different applications and requirements. Theoretical analysis shows that the compensation methods of the transmitter and receiver of the NR-based MC-WPT system would affect the operating frequency and output characteristics of the system. Moreover, by comparative analysis, the conditions and applicable ranges for a stable output of different topologies were provided. Finally, the experimental prototypes are set up by using the power electronic inverter and operational amplifier, and the voltage gain ratios of the four basic NR-based WPT topologies under the variations of transfer distance and load are observed. The experimental results validate the correctness of the theoretical analysis.

Design and research of a water energy piezoelectric energy harvester that changes the linear arrangement of magnet

In this paper, a water energy piezoelectric energy harvester (W-PEH) with altered linear arrangement of magnets is proposed and investigated. By changing the linear arrangement of magnets, the vibration frequency of piezoelectric patch is improved. The bottom magnet maintains the magnetic field balance of the entire magnetic coupling system, ensure the smooth running of the prototype. Piezoelectric patch is mounted at a reasonable angle to further enhance the output efficiency. Theoretical modeling and simulation explain the main factors affecting the output performance of W-PEH (the number of magnets arranged linearly and the installation angle of piezoelectric patch). To study the variables above and influence to the output performance, an experimental test system is built. Simulation and experiment show that the maximum output voltage and power of W-PEH are 8V and 1.25 mW respectively when the magnet is arranged linearly at 3 and the piezoelectric patch is installed at 30°. In the application experiment, W-PEH can successfully light up 72 light emitting diodes (LEDs), and real-time hydrological monitoring is possible. Therefore, W-PEH can greatly improve the efficiency of transmitting hydrological monitoring data through self-powered technology. Meanwhile, it provides a new solution for improving the output performance of water energy piezoelectric energy harvester.

Hybridized GWO-RUN optimized fractional order control for permanent magnet brush-less dc motor

The permanent magnet brush-less dc motor is a nonlinear, multivariable structure and magnetic coupled system wherein the load disturbances and the parameter uncertainties adversely affect the dynamic performance. From this, it required that the designed controller for the system must deal with the complexities. The objective of this paper is to introduce a novel fractional order proportional-integral controller for permanent magnet brush-less dc motor dealing with set parameter tracking problem. In this paper, in order to find the needed optimal gain parameters combination of metaheuristic and numerical optimization algorithm called Grey Wolf-Runge–Kutta algorithm is proposed. The efficacy of the proposed technique is demonstrated by comparing it with existing optimization technique viz. particle swarm, grey wolf, and Runge–Kutta algorithm. Furthermore, the stability and robustness analysis for the proposed controller is also studied for different operating conditions such as set speed variations, load disturbances and parameter variations. The simulation is performed using MATLAB toolbox. From the simulation results it is evident that FOPI controller optimized with novel hybrid algorithm guarantee the best set speed tracking and also capable to ameliorate the system robustness for parameter variations as well as external load disturbances.

Winding loss analysis of planar spiral coil and its structure optimization technique in wireless power transfer system

Circular planar spiral coils are wildly used for the magnetic coupling system in a high-frequency wireless power transfer system. The loss of the magnetic coupling system usually takes dominance in the whole system. This paper built the calculation model of magnetic field strength and coil loss, the proposed calculation model can effectively consider the mutual influence between the transmitter and receiver coil and accurately calculated the AC loss of WPT coils. Then, the effect of turn spacing on the AC resistance of coil is analyzed. It reveals that the proximity effect loss is greater when the coil is tightly wound, and the AC loss can be optimized by designing the turn spacing. Based on the above analysis, a double-layer coil method is proposed. This method can reduce the AC loss and improve the quality factor (Q) without changing the mutual inductance and footprint of coil at high frequency. The AC resistance of the double-layer coil method can be greatly reduced compared with the general method through simulation and experiment. The work efficiency of WPT system is increased by 4.3%, which verifies the accuracy and flexibility of theoretical analysis.

Selective assembly of magnetic nano-antenna for electromagnetic dissipation

A 3D anisotropic magnetic nanostructure is prepared using a selective assembly approach. Ultrabroad effective absorption bandwidth is achieved by the multi-scale magnetic coupling system we constructed.

Core Loss Analysis and Modeling of a Magnetic Coupling System in WPT for EVs

The magnetic core is an important part of the magnetic coupling system in wireless power transmission (WPT) for EVs. It helps to increase the coupling coefficient and reduce magnetic field leakage. However, it also brings additional core loss. While the traditional core loss model cannot be used directly due to the uneven distribution of the magnetic flux density, this paper focuses on the flux density distribution in the disk core of a WPT system. Based on a finite element analysis (FEA) simulation and a theoretical magnetic flux density distribution analysis, a mathematical model of magnetic flux density distribution is built, which is regarded as a quadratic function. Through this model, the flux density distribution can be calculated by the electrical and mechanical specifications of the magnetic coupling system. Combining the model of flux density distribution, the disk core loss model of the WPT system is proposed—the idea of which is dividing the disk core into several circle sheets firstly, and then summing the core loss of all circle sheets. Finally, the FEA simulation results verify the proposed model as being correct and flexible.

Dynamics modeling and analysis of the permanent-magnet synchronous motors bearing-rotor-magnetic field under rotor demagnetize

For the phenomenon of rotor demagnetization of Permanent Magnet Synchronous Motor(PMSM), studying the dynamic modeling and analysis of demagnetization rotor. Firstly, considering the unbalanced magnetic pulling (UMP) of the rotor under the demagnetization and the nonlinear Hertz contact generated by the rolling bearing, the double rectangular coordinate system of the stator and rotor is constructed, and the mathematical model of the unbalanced magnetic pull UMP is constructed with the rectangular coordinate as the variable. Then, the dynamics Jeffcott model of the bearing-rotor- magnetic fields coupling system in the condition of demagnetization is established. Based on this, the demagnetization status of permanent magnet in PMSM is described from three aspects: (1) rotor offset caused by demagnetization, (2) demagnetization angle, (3) decrease of air-gap MMF at the demagnetization angle. Through the analysis, it is found that there is a “saddle” point in the bifurcation plots of the rotor system with the change of demagnetization angle. The position of the “saddle” point in the bifurcation plots with the change of demagnetization angle is related to the speed. The research results of this paper provide a theoretical basis for demagnetization quantitative diagnosis and demagnetization vibration control of permanent magnet synchronous motor.

Rotational energy harvesting systems using piezoelectric materials: A review.

In the past few decades, rotary energy harvesting has received more and more attention and made great progress. The energy harvesting device aims to collect environmental energy around electronic equipment and convert it into usable electrical energy, developing self-powered equipment that does not require replaceable power supplies. This paper provides a holistic review of energy harvesting techniques from rotary motion using piezoelectric materials. It introduces the basic principles of piezoelectric energy harvesting, the vibrational modes of piezoelectric elements, and the materials of piezoelectric elements. There are four types of rotational energy harvesting technologies: inertial excitation, contact execution, magnetic coupling, and hybrid systems. An overview of each technology is made, and then, a detailed analysis is carried out. Different types of rotating energy harvesting technologies are compared, and the advantages and disadvantages of each technology are analyzed. Finally, this paper discusses the future direction and goals of improving energy harvesting technology. This Review will help researchers understand piezoelectric energy harvesting to effectively convert rotational energy into electrical energy.

Magnetically Coupled Electrical Machines for Renewable Energy Applications

Mechanical coupling between the drive and the driven systems in electrical machines poses design challenges. Rigid and flexible couplings have a trade-off between the rotational speed and vibrations, which are associated with misalignment. This paper discusses a procedure for obtaining the dimensions of a pre-designed rigid (flange-type) mechanical coupling system using the finite element-based electromagnetic full-wave simulator element software (FE, ANSYS) for a benchmark torque and proposes a process that replaces a mechanical coupling system by a magnetic coupling system. This paper also elaborates on the comparative performance analysis between magnetic coupling and mechanical coupling. The simulation results of this analysis affirm that adjusting the flange diameter and thickness tune the magnetic coupling system performance similar to that of the mechanical coupling with an added advantage of auto-decoupling when exposed to higher loads. The auto-decoupling property protects the mechanical and electrical system from damage. This research considers the use of COMSOL Multiphysics software for determining the optimum number of magnets to couple the flanges for specified torque and speed, the distance between the flanges, and limits of angular and parallel misalignments. JMAG software is used for the analysis of the dynamic behaviour of the magnetic coupling system and the holding torque characteristics. This manuscript shows that the magnetic coupling technique has promising results in the renewable energy industry, such as wind energy, wave energy and electric vehicles.

Selective magnetic responses of silicon nanoparticles modulated by waveguide structures.

High-refractive-index nanoparticles (NPs), such as silicon NPs, were considered as effective carriers in their response to a magnetic field at optical frequencies. Such NPs play an important role in many state-of-the-art technologies in nano-optics. Although the resonance properties of these NPs when varying their structural parameters have been studied intensely in the past few years, their interaction with the underlying substrate has seldom been discussed, in particular, when the substrate is a waveguide structure that significantly modulates the optical responses of the NPs. We proposed and studied a selective magnetic coupling system comprising a Si-NP on a metal-dielectric waveguide (MDW). The MDW structure supports either a transverse electric (TE) or a transverse magnetic (TM) mode that induces a large polarization dependence in the magnetic resonance. A new manifestation of the optical spin Hall effect was demonstrated in which a vertical rotating magnetic dipole excites a TE-type waveguide mode with a specific unidirectional emission. Making use of this polarization response, we developed a scanning imaging system that can selectively map the transverse or longitudinal magnetic field component of a focused beam depending on the type of MDW used in the system. This selective magnetic resonance coupling system is expected to be valuable for studying the fundamental interactions between the magnetic field and matter and for developing related nano-applications.

A Bioresorbable Magnetically Coupled System for Low‐Frequency Wireless Power Transfer

AbstractBioresorbable electronic technologies form the basis for classes of biomedical devices that undergo complete physical and chemical dissolution after a predefined operational period, thereby eliminating the costs and risks associated with secondary surgical extraction. A continuing area of opportunity is in the development of strategies for power supply for these systems, where previous studies demonstrate some utility for biodegradable batteries, radio frequency harvesters, solar cells, and others. This paper introduces a type of bioresorbable system for wireless power transfer, in which a rotating magnet serves as the transmitter and a bioresorbable antenna as the remote receiver, with capabilities for operation at low frequencies (<200 Hz). Systematic experimental and numerical studies demonstrate several unique advantages of this system, most significantly the elimination of impedance matching and electromagnetic radiation exposure presented with the types of radio frequency energy harvesters explored previously. These results add to the portfolio of power supply options in bioresorbable electronic implants.

Inductive coupling system for electric scooter wireless charging: electromagnetic design and thermal analysis

The paper deals with construction design and laboratory measurement of magnetic inductive coupling system suitable for electric scooter wireless chargers. It briefly elaborates design process relating to the system configuration, material used for construction and obtained operational conditions. The paper also discusses the thermal behavior of the couplers operating under load and describes fully automatic laboratory equipment for the system experimental testing.

PCB Layout Optimization of High-Frequency Inverter for Magnetic Coupled Resonance Wireless Power Transfer System

Magnetic coupled resonance wireless power transfer system has the advantages of long transfer distance and high efficiency. However, it needs a high-frequency AC power, and the influence of the circuit parasitic elements at high frequency cannot be ignored, which brings challenges to the research and the design of the high-frequency power for the wireless power transfer system. In this paper, the effect of the parasitic elements in the full-bridge inverter and the reasons of high-frequency ringing generated are analyzed in detail. The influences of device packaging and the printed circuit board (PCB) layout on circuit parasitic elements are studied. An optimized inverter PCB layout design that aims to reduce the parasitic elements and to provide a stable and high-quality AC power for the wireless power transfer system is presented. Finally, the performance of the conventional PCB layout design and the proposed optimized PCB layout design are compared through experiments. The experiment results show that the proposed design not only reduces the parasitic inductance in the circuit, but also reduces the electromagnetic interference noises and improves the stability of the inverter at 900kHz switching frequency.

An improved three-coil wireless power link to increase spacing distance and power for magnetic resonant coupling system

When wireless power transfer (WPT) technology is used to power the sensor networks, it is necessary to increase the transmission power and distance. We strictly deduced two necessary conditions for strong coupling by coupled mode theory. Next, the transmission power and efficiency as a function of coupling coefficient and quality factor are derived, and the maximum active power of the load depends on the coupling coefficient between resonators, quality factor of the resonator and the drive power. In order to increase transmission power and distance, an improved three-coil wireless power link is proposed. Meanwhile, an experimental platform was established, and the experimental results show that the transmission power can reach 120 W at a distance of 2.5 m. This proves that the improved three-coil wireless power link is very effective.

Analysis of Adjustable Magnetic Fluid Damper in DC Magnetic Field for Spacecraft Applications

A novel adjustable magnetic fluid damper is designed in this paper that dissipates the vibration energy by viscous flow of magnetic fluid with movement of inertia mass. First, considering the viscosity of magnetic fluid and the size of the damper, the theoretical model of the magnetic mechanical coupling system is established, and the flow velocity of the damper can be obtained from this model. Second, based on the magneto-viscous characteristic of magnetic fluid, the numerical simulation model of the cantilever and damper system is established. The distribution of magnetic field in the damper is studied. Finally, the displacement response and frequency response of the freely supported beam are calculated, and the flow distribution of the magnetic fluid in the damper is analyzed. This damper can finely adjust the damping parameters, and has good damping effect on the vibration of low frequencies and small damping.

Coupling Matrix Synthesis and Impedance-Matching Optimization Method for Magnetic Resonance Coupling Systems

The general coupling matrix representation of bandpass filter (BPF) circuits is a widely used technique that has simplified the analysis and optimization of complex microwave filters. In this paper, we demonstrate a novel application of the general coupling matrix for modeling wireless power-transfer (WPT) systems based on the BPF model of magnetically coupled resonators. Compared to other methods of WPT analysis, our model simplifies accommodation of complex loads and provides direct expressions for impedance matching (IM) in WPT systems. Using this tool, we achieve optimal IM for two resonator systems with a complex load, thus achieving the greatest possible power-transfer efficiency (PTE). Furthermore, our model reveals additional design constraints for optimizing PTE in coupled resonator systems exhibiting low quality factor and small interresonator coupling. Overall, this paper introduces a new, versatile framework for the analysis and optimization of coupled resonator WPT systems. Experimental results are presented, verifying the optimal IM design process.