Showing papers on "Magnetic circuit published in 2020"
TL;DR: A literature review is conducted on induction motor fault diagnosis techniques using FEM and the state-of-the-art techniques reported in the literature are categorized into three streams: first, FEM-based fault diagnosis approach, second, F EM and signal processing-based approach, and third, Fem, machine learning, and other advanced techniques-based approaches.
Abstract: Condition monitoring and fault diagnosis of induction motors serve as essential techniques toward the reliable operation of critical industrial processes. The finite element method (FEM) offers a great insight into fundamental principle and physical operation of the machine. It can model complex magnetic circuit topology, discrete windings layouts, and nonlinear magnetic material properties of the machine. It determines the machine parameters (such as the magnetic field distribution, flux density, electromagnetic torques, and stator current) and can model localized magnetic saturation due to faults to a high degree of accuracy. Used as fault detection algorithms, the FEM can address the issues such as the lack of comprehensive fault databases through field measurements, and the difficulty in distinguishing fault severity. It can reduce the number of destructive tests required in the field/labs, simulate any faulty states of the machine. Although FEM has been widely used in induction motors’ design and analysis, its application in fault diagnosis is limited despite the promising potential. In this article, a literature review is conducted on induction motor fault diagnosis techniques using FEM. The state-of-the-art techniques reported in the literature are categorized into three streams: first, FEM-based fault diagnosis approach, second, FEM and signal processing-based approach, and third, FEM, machine learning, and other advanced techniques-based approach. The advantages of fault diagnosis techniques using the FEM are demonstrated and the future research direction is recommended.
78 citations
TL;DR: A current harmonic suppression strategy based on an extended state observer (ESO) that works well when considering other factors that may cause harmonic distortion, such as magnetic circuit saturation, saliency ratio, over-modulation of the inverter, the voltage drop caused by electric devices, and dead time is proposed.
Abstract: Dual three-phase (DTP) permanent magnet synchronous machines (PMSM) have been utilized in many applications due to their outstanding performance. However, large stator current harmonics limit the further application of the DTP-PMSM due to the low impedance in the harmonic subspace. To solve this problem, this article proposes a current harmonic suppression strategy based on an extended state observer (ESO). A detailed analysis is carried out to demonstrate the disturbance rejection ability and robustness of the proposed method. The theoretical analysis also shows that the ESO strategy outstands the conventional proportional-integral controller and advanced proportional resonance (PR) controller in terms of harmonic reduction. The advantages are verified by simulation and experimental results under different operating conditions. The proposed strategy still works well when considering other factors that may cause harmonic distortion, such as magnetic circuit saturation, saliency ratio, over-modulation of the inverter, the voltage drop caused by electric devices, and dead time. Meanwhile, some limitations are also pointed out. The proposed strategy can also be easily applied to other multiphase PMSM types.
62 citations
TL;DR: The SMCHM can accurately calculate the flux density distributions and electromagnetic performance considering the heavy nonlinearity effect under the load conditions with fast computation speed and shows an excellent agreement between them.
Abstract: In this article, a new subdomain and magnetic circuit hybrid model (SMCHM) is proposed for on-load field prediction in the surface-mounted permanent-magnet machines. Equivalent current sheets are introduced to represent the nonlinearity effect, whose values are obtained by a magnetic circuit (MC) and correlated with boundary conditions in a subdomain model. The number of reluctances in the MC of the proposed model can be selected flexibly according to the nonlinearity effect. Instead of sectorial tooth in the conventional subdomain model, parallel tooth is considered in the proposed model to improve the accuracy. The SMCHM can accurately calculate the flux density distributions and electromagnetic performance considering the heavy nonlinearity effect under the load conditions with fast computation speed. The finite-element analysis is performed to validate the proposed model, which shows an excellent agreement between them. A prototype machine is manufactured to further prove these predictions.
57 citations
TL;DR: In this article, a hybrid-magnetic-circuit variable flux memory machine (HMC-VFMM) was proposed by combining series and parallel hybrid magnet structures, which achieved the synergies of wide flux regulation range in parallel type and excellent on-load demagnetization withstand capability in series type.
Abstract: This article proposes a novel hybrid-magnetic-circuit variable flux memory machine (HMC-VFMM) by combining series and parallel hybrid magnet structures. Thus, the synergies of wide flux regulation range in parallel type and excellent on-load demagnetization withstand capability in series type can be simultaneously obtained with the proposed HMC design. Meanwhile, two sets of the permanent magnets (PMs) with high coercive force and low coercive force (LCF), i.e., NdFeB and AlNiCo PMs, are employed to achieve high torque density and energy-efficient magnetization state adjustment. The topologies and tradeoffs of traditional parallel and series VFMMs are addressed first. In addition, the structure evolution, features and operating principle of the proposed HMC-VFMM are described, respectively. A simplified equivalent magnetic circuit is modeled to reveal the performance improvement of the machine. Then, the design improvements with q -axis barriers are presented to elevate the LCF PM working point for preventing the on-load demagnetizing effect, while maintaining the torque capability. The electromagnetic characteristics of the HMC design are investigated and compared with the parallel/series counterparts. Finally, the experiments have been carried out to validate the finite-element analyses.
55 citations
TL;DR: The interpolar flux leakage is significantly reduced with the developed design, which can improve the torque capability of this novel flux reversal permanent magnet machine with asymmetric-stator-pole (ASP) configuration.
Abstract: This paper proposes a novel flux reversal permanent magnet (FRPM) machine with asymmetric-stator-pole (ASP) configuration. Different from the conventional FRPM machine with uniform “NS-NS-NS” PM sequence, the proposed ASP-FRPM machine is characterized by a “NSN-S-NSN” magnet arrangement. Hence, the interpolar flux leakage is significantly reduced with the developed design, which can improve the torque capability. The machine topologies, features, and operating principle are introduced, respectively. A simplified magnetic circuit model is established to reveal the underlying flux leakage reduction mechanism of the ASP design, and the rotor pole number is analytically optimized as well. The design parameters are then globally optimized so as to improve the torque quality. In addition, the electromagnetic characteristics of the ASP- and conventional FRPM machines are compared. Finally, experiments have been carried out to validate the theoretical results.
42 citations
24 Jan 2020
TL;DR: This article delves into simultaneously applying the modular stator and segmented rotor to switched reluctance motors (SRMs) with a new double-stator segmented-rotor modular SRM (DSSR-MSRM), which has higher torque compared to the other structures.
Abstract: This article delves into simultaneously applying the modular stator and segmented rotor to switched reluctance motors (SRMs). In this regard, a new double-stator segmented-rotor modular SRM (DSSR-MSRM) with a new pole combination is proposed. First, the motor topology is introduced and the magnetic circuit model of the motor is analyzed. Next, the electromagnetic performances of the machine are analyzed using a finite-element analysis (FEA). The superiority of the DSSR-MSRM in terms of flux linkage and torque is illustrated based on a comparative study with five various types of SRMs with modular/nonmodular and segmented/nonsegmented structures with the same dimensions and parameters. The simulation results indicate that the DSSR-MSRM has higher torque compared to the other structures. Moreover, the dynamic performances of the proposed motor in terms of current, torque, and power waveforms are obtained. In addition, it is shown that the proposed motor has low torque ripple. Finally, the prototype motor is built, the mechanical considerations are discussed, and the experimental results are obtained, which are in a good agreement with those predicted from the FEA.
40 citations
TL;DR: In this paper, a magnetic integration method of single and multi-stage electromagnetic interference (EMI) filters is presented, where common-mode and differential-mode inductors are integrated into a single magnetic core unit to significantly reduce the filter volume.
Abstract: A magnetic integration method of single- and multi-stage electromagnetic interference (EMI) filters is presented. Common-mode and differential-mode inductors are integrated into a single magnetic core unit to significantly reduce the filter volume. A 500-W silicon carbon (SiC) single-phase inverter is used as an experimental platform. The magnetic integration model is designed, and the magnetic circuit analysis is conducted in a simulation to ensure that the core will not reach magnetic saturation under full-load conditions. The feasibility of the proposed method is verified by an EMI test in a simulation and an experiment. Compared with a traditional discrete passive EMI filter, the proposed integrated EMI filters can reduce 40% of the total volume and 69% of the inductor volume in an integrated single-stage EMI filter with satisfactory EMI suppression ability. Although the weight of integrated inductor of integrated multi-stage EMI filter (IMSEF) has 23.8% increment, the IMSEF shows a better EMI suppression ability and 4.6% inductor volume reduction.
39 citations
TL;DR: The key is to artificially construct reluctance effect in a consequent-pole Vernier permanent magnet machine (CP-VPMM) by introducing extra dc field excitation equipped with the relieving-dc-saturation ability, making it especially suitable for multimode starter generator application.
Abstract: Benefiting from flexible flux control and short-circuit withstand ability, the hybrid excitation machine is an emerging starter generator solution for hybrid electric vehicle propulsion. However, to realize a brushless hybrid design in conventional permanent magnet machines, a three-dimensional magnetic circuit is usually adopted, leading to complicated mechanical structure and torque density sacrifice. To address this issue, a new relieving-dc-saturation hybrid excitation Vernier machine is proposed in this article, which integrates good torque density and bidirectional flux control within a simple and brushless structure. The key is to artificially construct reluctance effect in a consequent-pole Vernier permanent magnet machine (CP-VPMM) by introducing extra dc field excitation equipped with the relieving-dc-saturation ability. In this way, the advantages of bidirectional flux control in stator-dc-excited reluctance machine and good torque density in CP-VPMM are well combined in this topology, making it especially suitable for multimode starter generator application. In this article, the machine structure and its design mechanism are introduced, with its electromagnetic performance evaluated by the finite-element simulation. A prototype is manufactured and tested. Experiment results verify the feasibility of this new topology.
36 citations
TL;DR: A new Vernier reluctance machine is proposed, which integrates the advantages of a robust rotor structure, good torque density, and flexible flux control ability, and little demagnetization risk exists for slot PMs during flux control.
Abstract: This paper aims to propose a new Vernier reluctance machine (VRM), which integrates the advantages of a robust rotor structure, good torque density, and flexible flux control ability. The key is to establish the excitation field with both stator slot permanent magnets (PMs) and zero-sequence current. Two excitation sources have different pole pair numbers but share a parallel magnetic circuit and contribute to superimposed torque in this machine. Meanwhile, a flexible flux control can be achieved by regulating zero-sequence current, and little demagnetization risk exists for slot PMs during flux control. In this paper, the machine configuration and operation principle are introduced, along with its integrated ac and dc drive method. Electromagnetic performance of this new machine is evaluated by finite-element analysis. Leading design parameters are determined and optimized considering optimal injection ratio of zero-sequence current. A prototype is fabricated, and relevant experiment results demonstrate the feasibility of the proposed solution.
35 citations
01 Dec 2020
TL;DR: The results of the development of a mathematical model of a synchronous motor and a study of the influence of the degree of saturation of the magnetic circuit on the transient processes of direct start-up are presented in this article.
Abstract: The results of the development of a mathematical model of a synchronous motor and a study of the influence of the degree of saturation of the magnetic circuit on the transient processes of direct start-up are presented. It is noted that the existing methods of research and calculation of transient processes of synchronous machines are based on the application of the superposition (superposition) method, which excludes their use in nonlinear systems.
33 citations
TL;DR: A modeling framework for electric motors based on MEC models including the electric interconnection including network theory is proposed that makes use of network theory, which allows to systemize and automate major parts of the modeling task.
Abstract: Accurate and real-time capable mathematical models are an essential prerequisite for the design of model-based controller and estimation strategies for electric motors. Magnetic equivalent circuit (MEC) models have proven to be an interesting alternative to classical inductor models that are typically utilized for the controller design. MEC models allow for a systematic inclusion of magnetic saturation and nonfundamental wave behavior of motors, while still having a manageable model complexity. The systematic derivation of the model equations can be rather involved, if in addition to the magnetic circuit of the motor also the electric interconnection is taken into account. For this reason, a modeling framework for electric motors based on MEC models including the electric interconnection is proposed. It makes use of network theory, which allows to systemize and automate major parts of the modeling task. The presented framework can be applied to a wide range of electromagnetic actuators. The feasibility of the proposed framework is demonstrated by the application to the modeling of a PMSM with (turn-to-turn) winding short circuit. A comparison with measurement results shows a high model accuracy of the resulting real-time capable model both for healthy and faulty conditions.
TL;DR: In this article, a novel structure of consequent pole dual rotor permanent magnet vernier machine (CPDRVM) is proposed, which consists of dual-sided stator in which windings are placed on the stator slots and magnets placed on inner and outer rotor slots.
Abstract: This article proposes a novel structure of consequent pole dual rotor permanent magnet vernier machine (CPDRVM). This structure consists of dual-sided stator in which windings are placed on the stator slots and magnets placed on the inner and outer rotor slots. Operation principles of the proposed VM carried out using flux modulation theory. The Finite Element analysis is utilized in order to evaluate the effect of magnet geometry on the produced torque and power factor. The motor characteristics and performance assessment are performed numerically. Furthermore, the parametric and sensitivity analysis are used to optimize the motor geometry. The proposed VM compared with PM machine and two conventional VMs. In this regard, performance indices such as flux, cogging torque, power factor, magnet volume, torque per magnet volume, Back-EMF, losses and efficiency profiles are calculated and compared. Results evidence better performance of the proposed structure. In fact, CPDRVM could produce higher torque density than conventional VMs. In addition, high power factor is reached for suggested topology.
TL;DR: In this article, a new controlled switching scheme that takes into consideration both core saturation and residual flux is proposed to reduce inrush currents in three-phase three-legged stacked-core power transformers.
Abstract: This article proposes a new approach for reducing inrush currents in three-phase three-legged stacked-core power transformers. Although magnitudes of inrush currents may not be as high as short-circuit currents, they are extremely detrimental to normal operation of power transformers. In this article, a new controlled switching scheme that takes into consideration both core saturation and residual flux is proposed to reduce inrush currents. Also, a transient model based on the duality transformation between electric and magnetic circuits is proposed, where a nonlinear inductance is used to simulate core saturation. The proposed scheme is demonstrated on a real transformer by both laboratory experiments and performing simulations. The Alternative Transients Program is used to simulate a wide spectrum of possible operating conditions. The experimental and simulation results show that inrush currents are significantly reduced after utilizing the proposed scheme. Therefore, the proposed controlled switching scheme will result in relaxing inrush-current-related constraints in designing and manufacturing three-phase power transformers, which, in turn, will reduce their cost.
TL;DR: In this article, a novel consequent pole E-core stator permanent magnet FSM is proposed and compared with conventional topology utilizing 2D finite-element analysis (2D-FEA).
Abstract: Flux switching machines (FSMs) encompass unique features of conventional direct current machine, permanent magnet (PM) synchronous machine and switch reluctance machine. Permanent magnet FSM (PMFSM) is capable of high torque density and applicable for high-speed application, however conventional PMFSM exhibits demerits of high PM volume, high torque ripples and significant stator flux leakage. In this paper, a novel consequent pole E-core stator PMFSM is proposed and compared with conventional topology utilising 2D finite-element analysis (2D-FEA). Finite-element analysis revealed that proposed design enhanced flux modulation effects by introducing flux bridges and flux barriers as a result reduced cogging torque by reducing 46.53% of the total PM volume, reduce torque ripples by reducing PM slot effects and reduce flux leakage utilising flux bridges in the stator. Furthermore, analytical model for flux linkages, cogging torque, mechanical torque, no load and on-load magnetic flux density (MFD) is developed for initial design of conventional and proposed model. 2D analytical methodologies resolve equivalent magnetic circuits for open-circuit flux linkages, Fourier analysis for cogging torque, Laplace equations for MFD and Maxwell stress tensor for mechanical torque. Finally, results obtained from 2D-FEA and analytical methodologies are validated and compared.
TL;DR: In this paper, an enhanced-torque switched reluctance motor with two sets of permanent magnets (PM-SRM) embedded inside the stator yoke and the end teeth of the neighboring modules is proposed.
Abstract: This article proposes an enhanced-torque switched reluctance motor with two sets of permanent magnets (PM-SRM) embedded inside the stator yoke and the end teeth of the neighboring modules. The PMs contribute to intensify the air-gap flux density and reduce the magnetic saturation in the stator poles. As a result, the output torque can be enhanced to a significant extent. The working principle of the proposed PM-SRM is clarified using its magnetic circuit model (MCM). The characteristics of the PM-SRM are obtained and compared with classical 12/8 and 6/5 SRMs and hybrid reluctance motors (HRMs) in terms of static and average torque and average torque per PMs volume. The steady-state performance of the PM-SRM in terms of current and torque waveforms is carried out, and the PM-SRM is compared with considered SRMs and HRMs in terms of output torque, power, and efficiency. All the comparisons demonstrate the out-performance of the proposed PM-SRM over other SRMs and HRMs. To validate the simulation results, a prototype of the PM-SRM is manufactured and the experimental results are obtained. Both the simulation and experimental results are indicative of the fact that the proposed PM-SRM can gain high torque and high PM utilization factor, simultaneously.
TL;DR: In this article, a self-sensing method using improved particle swarm optimization (IPSO) least square support vector machine (LS-SVM) is proposed, which eliminates the influences of displacement sensors fundamentally.
Abstract: An inverter-fed six-pole radial hybrid magnetic bearing (HMB) has the characteristics of compact structure, high support speed, long service life, and so on. However, using displacement sensors to detect rotor displacements leads to the problems of large volume, high cost, and low reliability. In this article, a self-sensing method using improved particle swarm optimization (IPSO) least square support vector machine (LS-SVM) is proposed, which eliminates the influences of displacement sensors fundamentally. The structure and working principle of six-pole radial HMB are introduced, and the mathematical model of its radial suspension force is deduced according to the equivalent magnetic circuit method. Based on the regression principle of the LS-SVM, the prediction model between the currents in control coils and the rotor displacements is established. Also, the performance parameters of LS-SVM are optimized by the IPSO algorithm, which realizes self-sensing modeling of rotor displacement. The simulation system for self-sensing modeling of rotor displacement for six-pole radial HMB is constructed, and floating experiment, static suspension experiment, dynamic suspension experiment, and disturbance experiment of the rotor are carried out, which verify the robustness and stability of the self-sensing method proposed.
TL;DR: In this paper, an ultrawideband differential magnetic near field probe with high electric field suppression is developed, where a pair of differential loops via fence and shielding vias below the loops are designed to reduce the electric field coupling.
Abstract: In this paper, an ultrawideband differential magnetic near field probe with high electric field suppression is developed. A pair of differential loops, via fence and shielding vias below the loops are designed to reduce the electric field coupling. It is shown that the electric field suppression of the proposed magnetic-field probe is higher than 30 dB up to 12.9 GHz and 21 dB up to 14 GHz. Due to the differential loops and shielding vias, the proposed magnetic-field probe shows better electric field suppression and sensitivity performance, while maintaining similar spatial resolution. Two other probes with single loop for sensing and without shielding vias are prepared for comparison.
TL;DR: The parameters of the motor are optimised via genetic algorithm to maximise the back-EMF voltage and the overall steady-state performance and the starting capability of theMotor is defined as the optimisation constraint.
Abstract: This study presents a comprehensive analytical analysis of line start permanent magnet (LSPM) synchronous motors in both steady-state and transient domains. The PM flux, the back-EMF and the winding inductances are first calculated in the steady-state based on the hybrid solution of magnetic circuit and the magnetic islands. Next, the motor voltage relations are mapped into an arbitrary d
-
q
reference frame to dynamically assess the transient speed response as well as the individual motor torque components. Based on the presented analytical modelling, the parameters of the motor are optimised via genetic algorithm to maximise the back-EMF voltage and the overall steady-state performance. Given the parabolic relation between the back-EMF and the braking torque, the starting capability of the motor is defined as the optimisation constraint. Finally, the analytical results are verified by using a finite element analysis software package.
TL;DR: The results show that the proposed motor has a high torque density and starting torque, and it greatly reduces the motor volume on the basis of a small cost difference.
Abstract: Given the problem that the drive system of the traditional mine transportation winch outputs a large traction force through the cooperation of an induction motor and reducer to meet the needs of a large traffic volume and heavy-load starting, this paper studies a low-speed and high-torque dual-stator permanent magnet direct drive motor with a separated magnetic circuit. The inner motor is a torque motor, and the outer motor is a direct drive motor, which is characterized by no magnetic circuit coupling and independent control. The proposed motor has an excellent heavy load starting ability and operation efficiency, and it improves the output torque without increasing the motor volume, which belongs to a special application. According to the working characteristics of the inner and outer motors and the constraints between the overall dimensions, the size equation is derived, and the design principles of the electromagnetic parameters, pole-slot combination and winding structure are described. The torque characteristics and temperature rise characteristics of the motor are simulated using the finite element method and compared with the torque performance and electromagnetic materials cost of the single stator low-speed and high-torque permanent magnet motor with different rotor structures. The results show that the proposed motor has a high torque density and starting torque, and it greatly reduces the motor volume on the basis of a small cost difference.
TL;DR: In this paper, the authors presented an accurate analytical model to compute the magnetic field in a short moving-magnet linear motor with any pole and slot combinations, and two kinds of end effects caused by the finite length of the stator and mover are considered.
Abstract: This article presents an accurate analytical model to compute the magnetic field in a short moving-magnet linear motor with any pole and slot combinations. Two kinds of end effects caused by the finite length of the stator and mover are considered. The stator end effect is addressed by an equivalent slotting subdomain based on the subdomain analytical method. The mover end effect is analyzed with a virtual mover consisting of the mover and two additional virtual units. The length of virtual unit is given according to the effective motion stroke and magnetic circuit, and the remanence of permanent magnets in virtual units is specified as zero. A linear motor with 8 poles/6 slots and a Halbach array is used to verify the correctness of the proposed analytical model. Compared with the results from the finite-element analysis and previous subdomain analytical model, the proposed analytical model shows high accuracy on the calculations of the magnetic flux density, cogging force, and normal magnetic force.
TL;DR: The main focus of this paper is to design and assess the characteristics investigation of Novel Dual Stator Pseudo-Pole Five Phase Permanent Magnet Synchronous Generator for wind power application and finds that the power density of the proposed generator is maximum.
Abstract: The main focus of this paper is to design and assess the characteristics investigation of Novel Dual Stator Pseudo-Pole Five Phase Permanent Magnet Synchronous Generator (NDSPPFP-PMSG) for wind power application. The proposed generator has a dual stator and two sets of five phase windings which enhance its power density and fault tolerant capability. The novelty of this generator is based on the fact that, eight magnetic poles are formed using only four poles of actual magnets on both the surfaces of the rotor. For the designing and optimal electromagnetic performance of the proposed generator, a Dynamic Magnetic Circuit Model (DMCM) is reported. To validate the results obtained from DMCM, Finite Element Method (FEM) has been opted owing to its high accuracy. For showing the performance superiority, the proposed generator is compared with two conventional generators namely, Dual Stator Embedded-Pole Five Phase (DSEPFP) and Single Stator Single Rotor Five Phase (SSSRFP) PMSG. To compare their performances, FEM results are considered. The electromagnetic performance namely, generated Electromotive Force(EMF), percentage(%) Total Harmonic Distortion(THD) of generated EMF, generated EMF vs speed, terminal voltage vs load current, electromagnetic torque developed on rotor vs time, %ripple content in the torque, and %efficiency vs load current are investigated for all the three generators. From these investigations, it is found that the power density (power to weight ratio) of the proposed generator is maximum.
TL;DR: A novel torque motor with hybrid-magnetization pole arrays is proposed that can significantly improve the output torque by range of 47–52% compared with traditional designs, while maintaining the system size and mass.
Abstract: Torque motor is one key component that directly influences the dynamic performance of jet pipe servo valve in aircraft. In this paper, a novel torque motor with hybrid-magnetization pole arrays is proposed. By changing the magnetization patterns of permanent magnets, the torque motor can significantly improve the output torque by range of 47–52% compared with traditional designs, while maintaining the system size and mass. The design concept and operating principle of the torque motor is presented. The magnetic field distribution is formulated analytically with equivalent magnetic circuit. Different from conventional study, the flux leakage of the permanent magnets and coils is included to improve the model precision. Subsequently, the output torque is derived mathematically from the airgap flux. Following that, the numerical calculation is conducted to validate the mathematical models of magnetic field and output torque. The design optimization is then carried out. One research prototype that can be mounted with either conventional magnet or the proposed hybrid array has been developed. The test rigs are constructed and experiments are conducted on the prototype. Both numerical computation and experimental results verify the significant improvement of torque generation of the proposed hybrid magnetization torque motor.
TL;DR: In this paper, a hybrid type magneto-rheological (MR) fluid damper based on electromagnet and two permanent magnets apart from electromagnetic fluid was designed and its characteristics were analyzed numerically.
Abstract: A hybrid type magneto-rheological (MR) fluid damper based on electromagnet and two permanent magnets apart from electromagnet was designed and its characteristics were analyzed numerically. In the proposed MR damper, the magnetic field is generated by the permanent magnet and raised by the additional electromagnet. This combination provides a larger amount of damping force with lower consumption of electric energy. The proposed model has an additional advantage of providing a moderate damping force in case of electromagnet failure. The magnetic circuit of a hybrid MR valve was analyzed by applying Kirchhoff’s law and magnetic flux conservation rule. A 2D axisymmetric model of the proposed hybrid MR damper was developed in commercial software where magnetic field properties are analyzed by finite element method. The optimization process was developed to optimize the geometric parameters and generated damping force using design of experiment (DoE) technique. The damping force of the MR damper was selected as an objective function. The optimal solution to the optimization problem of the hybrid MR valve structure was evaluated and compared with the solution obtained from the initial parameters. It is demonstrated that the novel hybrid type provides higher damping force than the previous model.
05 Oct 2020
TL;DR: An approach to the analysis of the dynamic behavior of turbine rotors and a generator of an energy gas turbine unit with active magnetic bearings as supports with full consideration of controlled electromagnetic processes in active magnetic bearing circuits is discussed.
Abstract: The paper discusses an approach to the analysis of the dynamic behavior of turbine rotors and a generator of an energy gas turbine unit with active magnetic bearings as supports. This unit is a part of the gas turbine cogeneration plant (GT CP). The problem of modeling the phenomena of rotor dynamics is solved with full consideration of controlled electromagnetic processes in active magnetic bearing (AMB) circuits. In order to analyze them, the method of contour flows similar to the method of contour currents for the analysis of electrical circuits is used. To describe the electromagnetic circuits of the AMB, detailed substitution schemes are introduced which take into account almost all the elements of the magnetic circuit (air gaps, sections of magnetic cores, grooves with windings, coils and other parts). Description of the considered mechatronic system requires constructing a mathematical model on the basis of application of the magnetomechanical Lagrange-Maxwell equations. The resulting system of differential equations relates to the generalized mechanical coordinates and flux linkages of the electric circuits of the AMB coils. The calculation results have the form of Cambell diagrams and amplitude-frequency characteristics of rotating rotors. Verification of the proposed approach to the modeling of dynamic phenomena in a rotary mechatronic system involves comparison with known calculation data. A comparative analysis reveals the advantages of the proposed approach for numerical simulation of the dynamics of rotors of controlled mechatronic systems and industrial electromechanical machines.
TL;DR: In this paper, the fundamental performances of two configurations of magnetoelectric transducers that are used the most in practice, longitudinal-longitudinal and longitudinal-transverse modes, with a focus on magnetic field sensing and wireless power transfer applications, were analyzed.
Abstract: This paper presents theoretical analysis on fundamental performances of two configurations of magnetoelectric transducers that are used the most in practice, longitudinal-longitudinal and longitudinal-transverse modes, with a focus on magnetic field sensing and wireless power transfer applications. Based on equivalent circuit models and two-port network theory, we derive explicit closed-form solutions for the magnetoelecitric voltage coefficient and the power delivered to a load. We reveal that although the former configuration exhibits some advantages of utilizing as a sensing system, there is no difference in the maximum output power obtained from the two methods. The question on how to reach the upper bound on transferred power is also discussed. The findings can be used as a generalized framework to design an optimal system, depending on desired applications.
TL;DR: In this article, a previously developed Active Magnetic Regenerator (AMR) model is integrated with an analytical model for a Magnetic Circuit (MCI) based on nested Halbach cylinders and with a model to determine the power consumption of the valve system (which modulates the fluid flow through the regenerators).
TL;DR: In this article, a multi-pole multi-layer magnetorheological (MR) brake with independent current supply was proposed to generate more flexible braking torque and lower power consumption.
TL;DR: In this article, a concise and practical analytical method of transmitted torque calculation for pre-design of Axial Permanent Magnetic Coupler (APMC) by combining Faraday's law with magnetic circuit model is proposed.
Abstract: In this article, a concise and practical analytical method of transmitted torque calculation for pre-design of Axial Permanent Magnetic Coupler (APMC) by combining Faraday's law with magnetic circuit model is proposed. The proposed method is able to consider the three-dimension (3D) edge magnetic effect as well as the induced magnetic field generated by eddy currents. The correctional skin depth factor is also taken into consideration. In order to verify the validity of the proposed method, the 3D finite element method (FEM) is employed. The results present that the relative error between the proposed method and 3D FEM in the normal working slip range is within 5.2%. Finally, detailed analysis is carried out to investigate the influence of the common parameters on the transmitted torque for APMC. Moreover, the deficiencies of this proposed method and the corresponding design considerations are also discussed, which offers useful and auxiliary information for the pre-design of APMCs.
TL;DR: In this article, an analytical model of modular spoke-type permanent magnet (MSTPM) machines based on air-gap field modulation (AFM) theory is proposed, and the machine performance is predicted by the analytical model, and verified by both finite element analysis (FEA) and experimental results.
Abstract: This article proposes an analytical model of modular spoke-type permanent magnet (MSTPM) machines based on air-gap field modulation (AFM) theory. Firstly, a fundamental AFM model of open-circuit MSTPM machines is introduced. The open-circuit air-gap field of MSTPM machines is determined by three fundamental elements including the primitive magnetizing magnetomotive force (MMF) produced by permanent magnet (PM), and two modulators which consist of stator and rotor permeance. The analytical MMF excited by PM (PM-MMF) can be calculated by using magnetic circuit method, while the stator and rotor permeance models are developed based on relative permeance (RP) method. Thereafter, a general model is proposed to calculate the open-circuit back electromotive force (EMF) of MSTPM machines. Further, the winding inductance model is established on the basis of equivalent magnetic circuit method and RP model. Finally, the machine performance is predicted by the analytical model, and verified by both finite element analysis (FEA) and experimental results.
TL;DR: In this paper, a three-dimensional magnetic equivalent circuit (3D MEC) method was proposed to analyze the flux linkage characteristics and electromagnetic force characteristics of double-sided switched reluctance linear machine (DSRLM).
Abstract: This paper proposes a three-dimensional magnetic equivalent circuit (3D MEC) method to analyze the flux linkage characteristics and electromagnetic force characteristics of double-sided switched reluctance linear machine (DSRLM). The 3D finite element model (3D FEM) of DSRLM is established to analyze the magnetic field line distribution of the motor. The magnetic field distribution of two representative positions (unaligned and aligned position) is mainly analyzed, and the reluctance of each part was obtained by the magnetic flux tube method. According to the similarity principle, the magnetic flux tube with irregular shape is equivalent to a simple magnetic circuit that is easy to calculate. According to the similarity of the magnetic circuit and electric circuit, the 3D MEC model of DSRLM was established. The Gauss–Seidel iteration method is used in MATLAB to solve the flux linkage-current curves at two representative positions. Then the flux linkage curves calculated by the MEC method are compared with the 3D-FEM results and experimental results. After that, the flux linkage curves obtained by MEC are used to solve the electromagnetic force curves. And the electromagnetic force curves are compared with the curves obtained by FEM and experiment. It can be found that the error is within an acceptable range, indicating that the scheme is more feasible.