New Topologies of High Torque Density Machine Based on Magnetic Field Modulation Principle

With the increasing demand for high torque density in motors,more and more new topologies emerge.Furthermore,the magnetic field modulation principle is widely concerned and has evolved into an effective analysis method for studying the new motor topology.This paper introduces the principle of magnetic field modulation.And the research on high torque density in recent years is reviewed from the perspective of magnetic field modulation,including permanent magnet vernier machine(PMVM),flux reverse machine(FRM),flux switching machine(FSM),dual permanent magnet(DPM)machine,and DC biased machine.The principle of magnetic field modulation makes it possible to propose higher torque density topologies in the future.

A Novel High Performance Magnetic Gear with Auxiliary Silicon Steel Sheet

Magnetic gear is a transmission device with novel structure.It uses the principle of magnetic field modulation to transmit torque.In view of the magnetic leakage of the magnetic gear in the process of rotation and cannot be eliminated,a magnetic gear model with auxiliary silicon steel sheet is proposed.Based on the conventional magnetic gear structure,the silicon steel sheet is placed outside the permanent magnet of the outer rotor.The magnetization mode of the outer rotor permanent magnet is tangential magnetization,and the spoke structure is adopted,and the inner rotor PMs is surface mounted and magnetized in the radial magnetization.The improved model is simulated by finite element method under three-dimensional conditions,and the electromagnetic performances of the model are optimized.Compared with the conventional magnetic gear model,the improved model has good performance,which improves the transmission capacity of output torque and reduces torque ripple.It is a great significance to improve the performance of magnetic gear.

Modulation of Void Motion Behavior in a Magnetized Dusty Plasma

Based on fluid equations, we show a time-dependent self-consistent nonlinear model for void formation in magnetized dusty plasmas. The cylindrical configuration is applied to better illustrate the effects of the static magnetic field, considering the azimuthal motion of the dusts. Tile nonlinear evolution of the dust void and the rotation of the dust particles are then investigated numerically. The results show that, similar to the unmagnetized one-dimensional model, the radial ion dragplays a crucial role in the evolution of the void. Moreover, the dust rotation is driven by the azimuthal ion drag force exerting on the dust. As the azimuthal component of ion velocity increases linearly with the strength of the magnetic field, tile azimuthal component of dust velocity increases synchronously. Moreover, the angular velocity gradients of the dust rotation show a sheared dust flow around the void.

An electrically tunable metasurface integrated with graphene for mid-infrared light modulation

We propose a low-cost plasmonic metasurface integrated with single-layer graphene for dynamic modulation of midinfrared light. The plasmonic metasurface is composed of an array of split magnetic resonators（MRs） where a nano slit is included. Extraordinary optical transmission（EOT） through the deep subwavelength slit is observed by excitation of magnetic plasmons in the split MRs. Furthermore, the introduction of the slit provides strongly enhanced fields around the graphene layer, leading to a large tuning effect on the EOT by changing the Fermi energy of the graphene. The proposed metasurface can be utilized as an optical modulator with a broad modulation width（15 μm） or an optical switch with a high on/off ratio（〉 100）. Meanwhile, the overall thickness of the metasurface is 430 nm, which is tens of times smaller than the operating wavelength. This work may have potential applications in mid-infrared optoelectrical devices and give insights into reconfigurable flat optics and optoelectronics.

Magneto and Electro-Optic Intensity Modulator Based on Liquid Crystal and Magnetic Fluid Filled Photonic Crystal Fiber

We propose a novel light intensity modulator based on magnetic fluid and liquid crystal（LC） filled photonic crystal fibers（PCFs）. The influences of electric and magnetic fields on the transmission intensity are theoretically and experimentally analyzed and investigated. Both the electric and magnetic fields can manipulate the molecular arrangement of LC to array a certain angle without changing the refractive index of the LC. Therefore, light loss in the PCF varies with the electric and magnetic fields whereas the peak wavelengths remain constant. The experimental results show that the transmission intensity decreases with the increase of the electric and magnetic fields. The cut-off electric field is 0.899 V/um at 20 Hz and the cut-off magnetic field is 195 m T. This simple and compacted optical modulator will have a great prospect in sensing applications.

Mechanism of Magnetic Pulse Wave Signal for Blood Pressure Measurement

Continuous non-invasive blood pressure (BP) measurement can be realized by using pulse transit time (PTT) based on electrocardiogram (ECG) and pulse wave signal. Modulated magnetic signature of blood (MMSB) is a promising approach to obtain PTT. The origin of MMSB is critical to establish the relationship between MMSB and BP. In this paper, two possible origins of MMSB, blood disturbance mechanism and angular variation mechanism, are analyzed and verified through three control experi-ments under different conditions. The influence of blood velocity alteration and blood volume alteration on magnetic field is investigated though blood flow simulation sys-tem. It is found that MMSB comes mainly from the periodic blood flow while the per-turbation caused by angular variation between sensitive axis of the magnetic sensor and geomagnetic field can be neglected. As to blood disturbance mechanism, the change of blood volume plays a decisive role while the effect of blood velocity altera-tion is negligible.

Engineering the electronic structure on MXenes via multidimensional component interlayer insertion for enhanced electromagnetic shielding

MXene-based functional electromagnetic interference(EMI)shielding films are highly desirable for mod-ern integrated electronic and telecommunication systems in aerospace,military,artificial intelligence,and smart and wearable electronics field.In this work,3D freestanding Ti_(3)C_(2)T_(x)/CNTs/Ni film assembled by 1D multi-walled carbon nanotubes(MWCNTs)/Ni and 2D Ti_(3)C_(2)T_(x)MXene sheets was synthesized by a facile vacuum filtration process.By electrostatic incorporation,hexagonal nickel plates embed on the CNTs and then the CNTs/Ni insert into the Ti_(3)C_(2)T_(x)layers to form magnetized Ti_(3)C_(2)T_(x)-based functional film with a compact and laminated structure.Due to the outstanding electron migration capacity in the highly conductive Ti_(3)C_(2)T_(x)sheet and multiple internal reflections from porous and segregated structures,the op-timized Ti_(3)C_(2)T_(x)/CNTs/Ni composite films show excellent EMI shielding effectiveness of 67.4 dB with elec-trical conductivity of 744 S cm^(-1).Surprisingly,a magnetization compensation strategy is built to boost the EMI shielding effectiveness with decreased conductivity.Meanwhile,the visual magnetic coupling phenomenon and charge distribution in the heterogeneous interfaces could be observed in the recon-structed electron holography images.Those encouraging results shed light on novel magnetized MXene-based functional films for high-performance EMI shielding.

Research on Slot-pole Combination in High-power Direct-drive PM Vernier Generator for Fractional Frequency Transmission System

Offshore wind energy is an important part of clean energy,and the adoption of wind energy to generate electricity will contribute to the implementation of the carbon peaking and carbon neutrality goals.The combination of the fractional frequency transmission system(FFTS) and the direct-drive wind turbine generator will be beneficial to the development of the offshore wind power industry.The use of fractional frequency in FFTS is beneficial to the transmission of electrical energy,but it will also lead to an increase in the volume and weight of the generator,which is unfavorable for wind power generation.Improving the torque density of the generator can effectively reduce the volume of the generators.The vernier permanent magnet machine(VPM) operates on the magnetic flux modulation principle and has the merits of high torque density.In the field of electric machines,the vernier machine based on the principle of magnetic flux modulation has been proved its feasibility to reduce the volume and weight.However,in the field of low-speed direct-drive machines for high-power fractional frequency power generation,there are still few related researches.Therefore,this paper studies the application of magnetic flux modulation in fractional frequency and high-power direct-drive wind turbine generators,mainly analyzes the influence of different pole ratios and different pole pairs on the generator,and draws some conclusions to provide reference for the design of wind turbine generators.

Enhanced modulation of magnetic field on surface plasmon coupled emission(SPCE) by magnetic nanoparticles

The obvious enhancement effect of magnetic nanoparticles(MNPs) introduced in Cr/Co/Cr/Au substrate on the pulsed magnetic field-modulated surface plasmon coupled emission(SPCE) was investigated,and the observed enhancement factor was 4 comparing with the magnetic field modulated SPCE without MNPs.This is the new observation for the magnetic field modulated SPCE,and this method was designed as a biosensor,which to our knowledge,is the first application of magnetic field-modulated SPCE in biosensing and detection field.This strategy is a universal approach to increase the fluorescence signal and helps to build the new SPCE based stimulus-response system.

Advanced Electrical Motors and Control Strategies for High-quality Servo Systems-A Comprehensive Review

Recent technological advancements have propelled remarkable progress in servo systems,resulting in their extensive utilization across various high-end applications.A comprehensive review of high-quality servo system technologies,focusing specifically on electrical motor topologies and control strategies is presented.In terms of motor topology,this study outlines the mainstream servo motors used across different periods,as well as the latest theories and technologies surrounding contemporary servo motors.In terms of control strategies,two well-established approaches are presented:field-oriented control and direct torque control.Additionally,it discusses advanced control strategies employed in servo systems,such as model predictive control(MPC)and fault tolerance control,among others.

Design,modeling and experimental investigation of a magnetically modulated rotational energy harvester for low frequency and irregular vibration

Vibration energy harvesting is a promising approach for sustainable energy generation from ambience to meet the development of self-powered systems.Here,we propose a novel compact non-resonant magnetically modulated rotational energy harvester(MMR-EH)for low frequency and irregular vibration.Through the rational arrangement of multiple magnetic fields in space,a ring route with low potential energy is established.A movable magnet can be non-contact modulated by the magnetic force to move along the ring route under irregular vibration,which is instrumental in electromechanical energy conversion.A dynamic model of the MMR-EH is developed based on the energy method and verified experimentally.The effects of key parameters on the magnetically modulated route are analysed.The simulation and experimental results demonstrate that the MMR-EH can effectively harvest the energy from ultra-low frequency(3 Hz)and irregular vibration.At a reciprocating vibration frequency of 10 Hz and an amplitude of 20 mm,the harvester can produce an average power of 0.29 mW.