Permanent Magnet Excitation Research Articles

An incremental permeability detection method for yield strength of ferromagnetic materials based on permanent magnet excitation

ABSTRACT In this paper, in order to meet the engineering requirements of mechanical properties detection of materials with low power consumption, a novel incremental permeability detection system based on permanent magnet excitation is proposed to reduce system power consumption. Initially, a new incremental permeability sensor was designed to extract magnetic incremental permeability (MIP) signal. Through finite element simulation, experimental parameters were optimised, and a rational arrangement of double permanent magnets was devised to furnish an optimally strong AC bias field intensity. Subsequently, a practical detection platform was assembled to extract electromagnetic signal features. From the perspective of domain wall displacement, a characteristic value θ was proposed to predict the yield strength, with experimental results yielding a relative error of less than ±10%. These experiments have validated the capability of permanent magnet-type MIP to enable quantitative detection of the yield strength in ferromagnetic materials.

MODELING OF SYSTEMS WITH THE PHOTOVOLTAIC POWER SOURCE AND WATER PUMPS

The article is devoted to the calculation of systems consisting of a solar photovoltaic power source and water pumps. It is noted that such systems can be used both in households or industry, and in agriculture, in particular for irrigation. Several variants of water pumps are shown. An analysis of the operational modes where the photovoltaic power source is connected to the pump has been carried out. The selection of equipment was carried out and the expediency of using a system with an electric energy booster was indicated. A booster for providing current during start-up modes can be a capacitor, a battery of capacitors or an ionistor. Emphasis is placed on the fact that for doing of such systems it is necessary to apply modeling with the use of electrical models. It is shown that for developing of electric models of solenoid-based pumps and pumps based on rotating direct current motors, it is necessary to use the methods of electromechanical analogies. Electrical models of a photovoltaic power source and, based on analogies, a solenoid-based pump and a direct current motor-based pump with permanent magnet excitation and parallel excitation were developed. When developing electrical models, controlled sources of voltage and current were used with mutual influence of the electrical and mechanical parts of the pumps. The need to use direct current motors with parallel excitation is indicated, as they are more stable to emergency modes. It is also stated that in general, the mechanical load of the rotating part of motors is non-linear and depends on the number of revolutions of the shaft. A nonlinear resistance that models a nonlinear mechanical load is shown, and it is noted that the higher-order nonlinearity is insignificant. Conclusions are drawn and further development in the direction of the use of digital technologies is outlined.

4D printing of Nd-Fe-B composites with both shape memory and permanent magnet excitation deformation

Novel composite filaments are developed by mixing PLA, TPU, and Nd-Fe-B components and utilizing melt extrusion for 4D printing. The results reveal that the Nd-Fe-B magnetic particles are uniformly dispersed in the PLA/TPU polymer matrix, and the composite filaments meet the requirements of high-precision printing. Increasing the proportion of Nd-Fe-B magnetic particles in the composite contributes to higher remanence, coercivity, and magnetic energy product for the printed magnets. Under the 70 °C thermal stimulus, it has a high shape fixed ratio (>99 %), a high shape recovery ratio (>90 %), and a rapid response time (≤6.55 s). The magnetic particles accelerate the shape recovery process. Moreover, the petal-like structure and the hollow ball structure are designed and printed. After deformation, each structure can nearly fully recover its initial shape. This recovery is achieved through a non-contact stimulus response based on ’thermal-magnetic’ coupling. The grippers printed by the developed composite show comprehensive properties of shape memory and magnetically controlled smart gripping.

A High Torque Density Dual-Stator Flux-Reversal-Machine with Multiple Poles Halbach Excitation on Outer Stator

This paper proposes a high torque density dual-stator flux-reversal-machine with multiple poles Halbach excitation (MPHE-DSFRM), which uses two pole pairs’ numbers (PPNs) of PM excitation on one outer stator tooth, and one PPN of PM excitation on one inner stator tooth. The introduction of different PPNs of PM excitation on the outer and the inner stators can optimize magnetic circuit and airgap flux density. A Halbach array is formed by inserting three pieces of circumferentially magnetized PMs into four pieces of radially magnetized permanent magnets (PMs) on the outer stator, which aims to further enhance torque density, and reduce torque ripple. Based on the flux modulation effect, the analytical modeling of the proposed MPHE-DSFRM is established, together with the evolution process, and the working principle is presented. Then, the key design parameters of MPHE-DSFRM are optimized to achieve high torque density and low torque ripple for high torque quality. Three representative DSFRMs and a conventional FRM are designed and analyzed, and they share the same design key parameters, including PM usage, outer radius of the outer stator, and active airgap length. The electromagnetic performances, including airgap flux density, back electromotive force (back-EMF), and torque characteristics, are analyzed and compared by finite element analysis (FEA). The calculated results show that the proposed MPHE-DSFRM can provide high torque density and high PM utilization.

Investigation of a novel intensifying-flux hybrid excited permanent magnet machine for electric vehicles

PurposeTo address the issues of the insufficient output torque associated with the application of intensifying-flux permanent magnet (PM) machines in electric vehicles, this paper aims to propose an intensifying-flux hybrid excitation PM machine. It is possible to adjust the air gap magnetic field by adjusting the field current in the excitation winding, thereby increasing the torque output capability and speed range of the machine.Design/methodology/approachFirst, a novel intensifying-flux hybrid excited permanent magnet synchronous machine (IF-HEPMSM) is proposed on the basis of intensifying-flux permanent magnet synchronous machine (IF-PMSM) and an equivalent magnetic circuit model is established. Second, the tooth width and yoke thickness of the machine stator are optimized to ensure the overload capacity of the machine while effectively improving the wide flux regulation range. Furthermore, the electromagnetic characteristics of the IF-HEPMSM are investigated and compared with the IF-PMSM and conventional permanent magnet synchronous machine (PMSM) by using finite element simulations.FindingsThe id of IF-HEPMSM and IF-PMSM is greater than zero low-speed magnetizing current. And the flux-weakening current of the IF-HEPMSM is 18% and 3% smaller than of the conventional PMSM and IF-PMSM.Practical implicationsAiming at the problems of IF-PMSM applied to electric vehicles, this paper proposes an IF-HEPMSM. The air gap magnetic field is adjusted by controlling the current of the excitation winding to improve the reliability of the machine. Therefore, the IF-HEPMSM combines the advantages of high-power density and high efficiency of the PMSM and the controllable magnetic field of the electro-excitation machine, which is of great engineering value when applied in the field of electric vehicles.Originality/valueThe proposed IF-HEPMSM offers better flux regulation capability with electromagnetic characteristics analysis and maps of dq-axis current as compared to IF-PMSM and conventional PMSM. Moreover, the improvement of the torque can make up for the shortcomings of the insufficient torque output capability of the IF-PMSM.

Hybrid permanent magnet synchronous generator as an efficient wind energy transducer for modern wind turbines

This paper investigates a novel control strategy that enables hybrid excitation permanent magnet synchronous generator (HPMSG) to track the optimal extracted power of the modern wind turbine type (NASA-NSF). The proposed control mathematical model is based on two cases of variable speed—Maximum Power Point Tracking (MPPT) and variable speed—Constant Power Point Tracking (CPPT). The later one is specified for wind gust and higher than rated wind speed withstanding operation. The HPMSG generator quantitative performance characteristics are presented and validated through simulation for both steady and dynamics states. Simulation results prove the capability of the generator to operate correctly under load and speed variation over both MPPT and CPPT. The output voltage stays, in both cases, within the much lower limits that imposed by maximum values.

Operational Analysis of an Axial and Solid Double-Pole Configuration in a Permanent Magnet Flux-Switching Generator

There are two main beneficial characteristics that doubly salient permanent magnet (PM) electrical machines present for aircraft applications: armature windings and PMs excitation sources placed on the stator side (maintenance and thermal management), and having a clear-cut rotor without PMs or excitation windings (vulnerable at high speeds due to associated centripetal mechanical stresses). Within this framework, a doubly salient permanent magnet (DSPM) generator was conceived by optimizing the stator size and rotor structure to minimize the torque ripple and maximize the root-mean-square (RMS) voltage value per turn of each generator phase. Firstly, a comparison between the 2D and 3D finite element method (FEM) models is made considering the results of 3D finite element analysis (FEA) as our benchmark in order to understand the accuracy of the 2D results against our benchmark model, the 3D one. A multi-objective design strategy based on a 2D FEA is made, it is set to have characteristics closest to optimal for a Boeing 767 turbine, that is, the necessary electromotive force for a required power of 90 kW at 3000 rpm, feeding a simplified Boeing 767 electrical power distribution system. The results show that the machine could not deliver the required power at 3000 rpm since the 2D FEA demonstrates that the 2D model gives optimistic results when compared with the 3D FEM model. However, with a 3D FEA of the machine feeding the aircraft load, it was seen that the machine’s efficiency is 92%, suggesting that this machine can be a plausible solution.

Design and Analysis of the High Torque Density Circumferentially Excited Permanent Magnet Motor Based on PSO

Design and Analysis of the High Torque Density Circumferentially Excited Permanent Magnet Motor Based on PSO

Design and Performance Research of a Novel Iron-Core Permanent Magnet Compensated Pulsed Alternator With Segmental Squirrel-Cage

Compensated pulsed alternator (CPA) can realize transient high current discharge by compressing magnetic field through compensating element, which has important application in pulse power field. The compen- sation shield and short circuit compensation winding are usually used as compensation elements, but the local compensation effect will be affected by the opposite eddy currents or conductor currents under other poles at maximum discharge time. To solve this problem, a novel iron-core permanent magnet CPA (PMCPA) with segmental squirrel-cage is proposed in this paper. At the time of maximum discharge, the bars' current of each segmental squirrel-cage segment will not be affected the bars' currents in opposite direction of other segments, which has better local compensation effect. In addition, the permanent magnet (PM) excitation eliminates the brush and slip ring and improves the reliability of operation. First, the design basis and scheme of the PMCPA are introduced. Second, the dynamic mathematical model of the PMCPA is presented. Third, the finite-element model of the PMCPA is established to analyse. Fourth, the prototype is manufact- ured to test and validate. Through analysis and verification, the superiority of segmental squirrel-cage compensation is proved, which provides a new idea for the optimization and development of compensation elements.

Experience in Developing a Synchronous Electric Motor with Permanent Magnet Excitation

Experience in Developing a Synchronous Electric Motor with Permanent Magnet Excitation

Design and Analysis of a Multi-unit Distributed Permanent Magnet Arc Motor Having Double-Sided Permanent Magnet Excitations

Design and Analysis of a Multi-unit Distributed Permanent Magnet Arc Motor Having Double-Sided Permanent Magnet Excitations

Hybrid optimized-ANFIS based MPPT for hybrid microgrid using zebra optimization algorithm and artificial gorilla troops optimizer

This paper presents an effective hybrid renewable energy system. This system utilizes primary energy sources represented by both photovoltaic (PV) and wind energy conversion system (WECS). In addition, integrating the battery energy storage system (BESS), the hydrogen energy storage system (HESS), and the supercapacitor energy storage system (SESS), as backup sources which providing reliable simultaneous power supply and loading. A new design for a wind energy conversion system based on a hybrid excitation permanent magnet synchronous generator (HEPMSG) is proposed, and then artificial intelligence strategies are utilized to determine the optimal flow of energy when the system is operating immediately. Moreover, new hybrid maximum power point tracking (MPPT) techniques have been proposed including zebra optimization algorithm (ZOA)-ANFIS-based MPPT and gorilla troops optimizer (GTO)-ANFIS-based MPPT to obtain the maximum power of solar panels and wind turbines, which leads to enhancing the performance of these energy sources. The implemented power flow management (PFM) model is designed by MATLAB/Simulink, considering three various operating cases to evaluate the performance and effectiveness of various backup system configurations under different operating scenarios. According to the results, power can be generated, and load requirements can be efficiently met by applying the proposed PFM strategy, and this leads to the system operating at optimal performance. When comparing two optimization techniques, it will become clear that both give robust performance, but ZOA technique significantly outperforms the GTO technique in the computation time (26.17 % reduction) for the photovoltaic system. On the other hand, in the case of the wind energy conversion system, the ZOA technique achieves a significant reduction in calculation time by 35.5 %. The ZOA technique achieves computation times of 1616.80 s and 672.43 s for the photovoltaic and wind energy conversion system, respectively.

Toroidal Field Excitation for Axial-Field Double-Rotor Flux-Reversal DC Motors With Magnetic Differential

In order to provide differential action for electric vehicles performing reliable cornering, the axial-field (AF) double-rotor (DR) flux-reversal (FR) motor shows a good ability of torque output along with magnetic differential (MagD) control on its two rotors. Apart from using the permanent magnet (PM) excitation, which suffers from high PM cost and risk of accidental demagnetization, this paper proposes the toroidal DC (TDC) windings for field excitation to avoid the problems associated with PMs. The TDC windings not only serve as the source of the magnetic field but also regulate the flux on two rotors to produce MagD action. By using three-dimensional finite element analysis, motor performances between using the TDC windings and the conventional concentrated DC (CDC) windings are quantitatively compared, which validates that the proposed AF-DR-FR-TDC motor takes definite advantages over the CDC counterpart while offering the desired MagD action.

Magnetic focusing of low-power Hall thruster with a center-mounted hollow cathode

Magnetic focusing with xenon propellant has been verified in orbit from medium-to high-power Hall thrusters but has yet to be achieved in low-power Hall thrusters. A magnetically focused Hall thruster was designed to solve the common issue of large plume divergence angle in low-power Hall thrusters, which realizes the plasma lens magnetic field topography with permanent magnet excitation on the wide channel and adopts the center-mounted cathode layout. Experimental results indicate that the HEP-300CHC thruster exhibits an optimal magnetic focusing mode when operated at 288W with plume divergence half-angle approximately 11.7°. The magnetic focusing range is relatively narrow, concentrated within discharge voltage between 210V and 230V, and anode flowrate between 18sccm and 20sccm.The anode efficiency is higher than 40% at the nominal power, and the maximum anode efficiency reach 52% at the discharge power of 300W. This study provides a reference basis for ion beam control of low-power Hall thrusters.

Electromagnetic Characteristics Analysis and Torque Ripple Reduction for Doubly Salient PM Machine

In this paper, the air-gap field modulation analysis and torque ripple reduction method for doubly salient permanent magnet motor (DSPMM) are presented. Based on the flux linkage distributions in the motor, the equivalent magnetic circuit models for permanent magnet (PM) and armature winding excitations are built, respectively. The air-gap magnetomotive forces (MMFs) caused by PM MMF and armature MMF can be obtained by combining the air-gap permeance and equivalent magnetic circuit models. The electromagnetic properties of the DSPMM are investigated from the perspective of air-gap field modulation principle. It is revealed that multiple field harmonics contribute to torque generation, and the torque ripples of the DSPMM are mainly caused by the cogging torque. To reduce the torque ripples, the 5th or 7th harmonic currents can be injected into the armature winding to compensate the cogging torque, and their analytical formulas will also be given. The finite element simulations and experiments are carried out to verify the results of theoretical analysis and the effectiveness of the proposed control method.

An Accurate Efficiency Calculation for PMSG Utilized in Renewable Energy Systems

Considering the importance of optimizing renewable energy systems, this paper aims at calculating the exact efficiency of a stand-alone wind turbine connected to a synchronous generator with permanent magnet excitation (PMSG). By accounting for mechanical and electrical losses (copper losses, stray load losses, iron core losses, friction losses, windings losses, and magnetizing saturation effect), the study investigates the impact of wind speed on the generator's performance and efficiency in addition to the impact of losses on the overall efficiency of (PMSG). The simulation of the PMSG dynamic model 8.5×(10)^3 V․A is executed using MATLAB/Simulink, employing a simplified equivalent circuit that accurately represents the PMSG's behavior under steady-state conditions with resistive loads. Wind speeds of 12 and 14 meters/second are chosen as fixed values to demonstrate the effect of varying wind speed on efficiency. The obtained results reveal the influence of wind speed on the PMSG efficiency. The presented findings contribute to the understanding of PMSG performance and can aid in optimizing the stand-alone wind turbine systems, they also show that the wind had an effect on the efficiency values that were obtained (97.86% at 12m/s and 97.91% at 14 m/s), while the effect of losses was very few around 3%. However, the obtained results are very good compared to previous studies to show the accuracy and validity of the suggested dynamic model.

Analysis and Suppression of Cross-Coupling Demagnetization in Dual Permanent Magnet Machine for Direct-Drive Application

Dual permanent magnet (PM) machines synthesize two PM excitations together and potentially exhibit higher torque density than conventional single-PM excited machines. In dual-PM excited machines, the existence of one PM excitation tends to cause interior flux density reduction and irreversible demagnetization of the other PM set, and this feature is recognized as cross-coupling demagnetization. Therefore, this article systematically analyzed the mechanism and influence of this unique phenomenon in a dual-PM prototype machine. The results reveal that the cross-coupling demagnetization can result in up to 18% torque reduction under a severe working conditions if the machine is not properly designed. Increasing one set of PM thickness along the magnetization direction is beneficial to enhance the self-demagnetization withstanding ability, whereas the cross-coupling demagnetization on the other PM set has deteriorated. In order to eliminate such a side effect, some techniques, e.g., removing the demagnetization region and alleviating the mutual flux path, are presented to suppress the demagnetization. It is revealed that the demagnetization rate can be reduced to less than 3% with proper design. Finally, a dual-PM prototype is manufactured and tested to validate the improvement of demagnetization withstanding capability by using the presented suppression technique.

Analysis of Synergistic Stator Permanent Magnet Machine With the Synergies of Flux-Switching and Flux-Reversal Effects

Dual permanent magnet (PM) machines have attracted numerous interests due to the high torque density and compact volume <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">.</i> This article investigates a synergistic PM machines with the synergies of flux switching and flux reversal effects. The flux-reversal and flux-switching PM (FSPM) flux paths circulate from two sides of the split teeth separately, which avoid the over-saturation with dual PM excitations. The preferred stator and rotor pole number is derived from a simplified analytical model and the influence of leading parameters is analyzed as design guidelines. Furthermore, the synergistic stator PM machine is optimized and compared with FSPM machines. It is revealed that the synergistic stator PM machine exhibits ∼20%, ∼10%, and ∼17% higher torque density than conventional FSPM machine, C-core FSPM machine, and E-core FSPM machine, respectively. Besides, good flux weakening capability is achieved with a larger inductance than conventional FSPM machine, and higher efficiency is obtained at both low-speed and high-speed operations. Finally, an experimental prototype is fabricated to validate the proposed concepts.

Influence of end-effect and end-winding on the electromagnetic losses and efficiency in high speed permanent magnet machines

&lt;span&gt;Permanent-magnet excitation machines (SPMMs) having mounted magnet on the outer surface of their rotor are preferred for high speed applications such as turbochargers, mechanical turbo-compounding systems, racing engines and fuel pumps, over other types of machines including induction and switched-reluctance machines, since the SPMMs integrate the features of high torque density, compact rotor structure, high reliability and simple structure. However, in the SPMMs, due to the need for a retaining sleeve for the rotor, a large magnetic airgap results and consequently a large magnet thickness is required, hence the magnetic end-effect is relatively high. On the other hand, the use of an overlapping distributed winding leads to a significantly large end-winding length. Hence, the end-effect and the end-winding influences on the performances of a high-speed SPMM is considered in this paper. With a view to get the impact of the end-effect, a comparison between three-dimensional (3D-FEA) results and counterparts two-dimensional finite element analyses (2D-FEA) have been conducted. Results show that, higher efficiency at low torque and low speed due to the low electromagnetic losses and at high speeds due to the high flux-weakening capability are seen when the influences of end-effect as well as end-winding are taken into account.&lt;/span&gt;

Research on Active Disturbance Rejection Thrust Stability Control of Permanent Magnet Reluctance Linear Motor

Permanent magnet reluctance linear motor (PMRLM) has high thrust density, simple and reliable structure due to the structure of permanent magnet and current double excitation. It is suitable for all kinds of large factories and logistics sorting centres. However, the existence of double salient pole structure and permanent magnet flux harmonic, the thrust pulsation of the motor is very large. In view of the above problems, the mathematical model of PMRLM is established, and the ADRC technology is proposed to be introduced into the thrust stability control. By building a simulation platform and comparing with the traditional PID control, the results show that the ADRC effectively reduces the thrust pulsation to a certain extent, and has good robustness and anti-interference.