Winding Function Model-based Performance Evaluation of a PM Transverse Flux Generator for Applications in Direct-drive Systems

The magnetic flux in a permanent magnet transverse flux generator(PMTFG) is three-dimensional(3D), therefore, its efficacy is evaluated using 3D magnetic field analysis. Although the 3D finite-element method(FEM) is highly accurate and reliable for machine simulation, it requires a long computation time, which is crucial when it is to be used in an iterative optimization process. Therefore, an alternative to 3DFEM is required as a rapid and accurate analytical technique. This paper presents an analytical model for PMTFG analysis using winding function method. To obtain the air gap MMF distribution, the excitation magneto-motive force(MMF) and the turn function are determined based on certain assumptions. The magnetizing inductance, flux density, and back-electro-magnetomotive force of the winding are then determined. To assess the accuracy of the proposed method, the analytically calculated parameters of the generator are compared to those obtained by a 3D-FEM. The presented method requires significantly shorter computation time than the 3D-FEM with comparable accuracy.

Development of a Consequent Pole Transverse Flux Permanent Magnet Linear Machine with Passive Secondary Structure

Transverse-flux machines have the advantage of high force density owing to the peculiarity of decoupling of electric loading and magnetic loading.In this paper,a novel consequent-pole transverse-flux permanent magnet linear machine(CP-TFPMLM)is proposed and investigated.The origination of the proposed machine is from an existing transverse-flux flux-reversal linear machine(TF-FRLM),by partially replacing permanent magnet poles with soft magnetic iron for further reducing the cost of magnets.The fundamental structure and operating principle are introduced at first.The electromagnetic performance,including back EMF,detent force,and thrust force,are investigated with the finite element method.The proposed machine can achieve similar performance as compared to the TF-FRLM but with half of the magnets are used.

Development of a New Flux Switching Transverse Flux Machine with the Ability of Linear Motion

This paper proposes a new rotary flux switching transverse flux machine with the ability of linear motion(FSTFMaLM),in which both the stator and the rotor cores are made by using soft magnetic composite(SMC)materials.With the special design pattern,for the rotary motion model,the proposed machine can combine both the advantages of the flux switching permanent magnet machine(FSPMM)and the transverse flux machine(TFM).It can output with relatively high torque density,and as there is no windings or the magnets on the rotor cores,the proposed machine can operate in the high speed region to improve the output power.With the adoption of the SMC materials,the manufacturing of this machine can be quite easy.By stacking the rotor core together and prolong it with the determined length in the axial direction,in addition with the special control algorithm,the proposed machine can have the ability of the linear motion.In this paper,the operation principle of this machine has been explained and the design methods are also presented.To seek the better performance,the main dimension of the machine is optimized,and for the performance evaluation,the finite element method(FEM)is adopted.The proposed machine can be used for the electric driving systems,robotic systems or other applications where the linear motion ability is required.

Stationary-frame current control strategy for transverse flux permanent-magnet machine

A new stationary-frame AC current control strategy that can eliminate steady-state errors is discussed and applied to the control of transverse flux permanent-magnet machine （TFPM）. Based on the principle of modulation and demodulation, this AC controller can achieve the same frequency response characteristic as the equivalent DC controller. Validity of the TFPM control system using this current control strategy is confirmed with simulation results.

Transverse Flux Induction Coil for Uniform Bar Heating Excluding Edge

This work particularly focuses on compensating Joule heat in under-heated areas occurred when thin steel bar is(<20 mm)heated by transverse flux induction heater(TFIH).The under-heated areas take place in range of 50~150 mm from the both edges,so Transverse Flux Induction Coil(TFIC)including a magnetic core is proposed and optimized to supplement this fault.The solutions on the electromagnetic field are obtained numerically by commercial code MAXWELL 3D software from ANSYS Corp.and then,verified experimentally by pilot-scale tests,in which the TFIH was manufactured with a nominal power of 100 kW at a fundamental frequency of 1 kHz.Ultimately,TFIC having geometrically the optimized magnetic core made the heating pattern U-shaped,so could supply a desirable temperature profile for the rolling process.

Fundamental Design and Analysis of a Novel Bipolar Transverse-Flux Motor with Stator Permanent-Magnet Excitation

In this paper,a novel bipolar transverse flux motor with stator permanent magnet excitation is proposed based on the summary and analysis of the transverse flux motor and stator permanent magnet motor research achievements in recent years.It has been shown that the motor realizes the bipolar winding flux through the detailed analysis.The motor can be used as an inwheel motor in electric vehicles because of its external rotor and permanent magnets mounted on the stator radial surface.Secondly the basic structure and working principle of the motor are introduced.Then the relationship between the motor power and its dimensions is deduced.Thirdly the 3 dimensional finite element method(3D FEM)is used to analyze the static and transient characteristics,including the no-load magnetic field distribution and winding back EMF.Finally a three-phase 600W prototype has been made and the experimental analysis is carried out.

Transversal Flux Scanning Induction Heating of Magnetic Nonlinear Steel Sheets With Temperature Dependent Properties

This paper deals with finite element study of the scanning induction heating of the magnetic steel sheets in transversal flux devices,taking into account the magnetic nonlinearity and the dependence on temperature of steel properties.The decrease of the non-uniformity of the transversal profile of sheet heating as effect of the magnetic or electromagnetic screening of the sheet lateral sides was proved.

Simulation of high-frequency gravitational wave detection using modulated Gaussian beam

This paper investigates the feasibility of using a Li-Baker detector based on a modulated Gaussian beam to detect gravitational waves in the GHz band.The first-order perturbation photon fluxes(PPF,signal of the detector)and the background photon fluxes(BPF,main noise of the detector),which vary with time,and the transverse distance are calculated.The results show that their propagation directions and energy densities are much different in some areas.Apart from BPF,we also consider two other important noises:diffraction noise and shot noise.In the simulation,it is found that the diffraction noise and shot noise are both lower than the signal level.Meanwhile,the main noise(BPF)can be eliminated when the receiving screen is located in certain special transverse areas where the BPF direction is opposite to that of PPF.Thus,the signal to noise ratio(SNR)obtained using our detection method can reach up to 320 in some transverse areas.These results are beneficial for the design of the Li-Baker detector.