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The contactless transmission between the conductor rotor and the permanent magnet (PM) rotor of an adjustable permanent magnet coupler (APMC) provides the device with significant tolerance for alignment errors, making the performance estimation complicated and inaccurate. The first proposal of an edge coefficient in this paper helps to describe the edge effect with better accuracy. Accurate equivalent magnetic circuit (EMC) models of the APMC are established for each region. Models of magnetic flux, magnetic resistance, and eddy current density are established by defining the equivalent dimensional parameters of the eddy current circuit. Furthermore, the concept of magnetic inductance is proposed for the first time, parameterizing eddy currents that are difficult to describe with physical models and achieving the modeling of the dynamic eddy current circuit. The magnetic resistance is subdivided into two parts corresponding to the output and slip according to the power relationship. Furthermore, eddy current loss and dynamic torque models are further derived. The method proposed in this paper enables the APMC to be modeled and calculated in a completely new way. The correctness and accuracy of the model have been fully demonstrated using finite element simulation and an experimental prototype. In addition, the limitations of the proposed method and the reasons are fully discussed and investigated. [ABSTRACT FROM AUTHOR]

Permanent magnet (PM) machines have been extensively used for various applications. Nevertheless, thermal effect, particularly hotspot temperature, not only severely restricts power/torque density but also leads to deteriorations in electromagnetic performance, service life, and reliability. Starting with foundations of PM machines and heat transfer mechanisms, this paper reviews the development of thermal analysis methods over the last thirty years and the state-of-the-art research achievements, and the hotspot temperatures of winding and PM are particularly evaluated. In the overview, various machine losses and cooling techniques are first introduced, which are the essential reasons for temperature rise and the most straightforward way to remove the generated heat. Afterwards, the mainstream thermal analysis techniques, i.e., numerical techniques, lumped-parameter thermal model, and hybrid thermal models, as well as the online electrical parameter-based and thermal model-based temperature monitoring techniques, are reviewed and assessed in depth. In addition, this paper also reviews the analytical thermal modelling methods for winding and PM. Finally, future research trends are highlighted. [ABSTRACT FROM AUTHOR]

In this paper, a mechanical model of the deflection dual-stator switched reluctance generator (DDSRG) is developed, and the advantages of the dual-stator structure for the deflecting motion are analyzed. Secondly, the spatio-temporal and spatial distribution characteristics of the inhomogeneous electromagnetic force are derived analytically and further verified by fast Fourier transform (FFT).Thirdly, the spatial and temporal distributions of electromagnetic forces of DDSRG are calculated based on finite element software, and the distributions of electromagnetic forces under different motion states are analyzed. By combining the analysis of modal analysis and harmonic response analysis, the free mode and vibration response acceleration variation laws of the internal and external stator are determined. The results show that the order of electromagnetic forces on the stator at rated speed is mainly 8 times the fundamental frequency, and the modal vibration order is more violent in the order of 2–7. Finally, the experimental platform of DDSRG is built, and the vibration characteristics are tested to verify the validity and accuracy of the proposed simulation results. [ABSTRACT FROM AUTHOR]

This study proposes a hybrid excited (HE) doubly salient machine with permanent magnets (PMs) located on stator slot openings. The HE machine inherits the high torque density of PM machines as well as flexible magnetic field regulation of wound field machines. Since the PMs are located at stator slot opening, the PM flux is shunted in the stator without DC excitation, and the machine exhibits high fault‐tolerant capability at high‐speed operation. The proposed machine is optimised, together with a comparison with a conventional stator slot PM HE machine. It is revealed that the proposed HE machine exhibits a significantly higher torque density under the same copper loss and PM usage. Finally, a prototype is fabricated, and experiments have been conducted to verify the accuracy of finite element simulation on the proposed machine topology. [ABSTRACT FROM AUTHOR]

This study presents a hybrid excitation permanent magnet synchronous generator (HEPMSG) with a stator third harmonic winding to solve the problems of adjusting the air‐gap magnetic field of the permanent magnet synchronous machine (PMSM) and simplify the excitation system structure. The electromotive force (EMF) of the stator third harmonic winding, induced by the inherent third harmonic magnetic field in the air gap, provides the adjustable field current for the rotor field winding via the controllable rectification. The proposed machine structure is described, and the generation mechanism and the excitation principle of the stator third harmonic EMF are analysed. The conditions for maximum excitation current output are discussed, and the integrated design methods of the stator third harmonic winding and the rotor excitation winding are described. Based on the finite element method, the performances of the third harmonic excitation system are numerically compared for different stator third harmonic windings, and the open‐circuit voltage regulation characteristics under different control angles are analysed. A 2.5 kW HEPMSG prototype with a stator third harmonic winding is manufactured and tested. The predicted and experimental results are in good agreement, which verifies the correctness of the excitation principle of the proposed HEPMSG. [ABSTRACT FROM AUTHOR]

Here, machines having permanent magnets (PM) mounted in the stator are compared during fault operations such as armature winding short circuits. The magnet potential irreversible demagnetisation is also investigated due to the fact that the PMs are placed close to the armature coils (heat sources) and hence are prone to temperature-related demagnetisations. It is found that the doubly salient and flux reversal machines have inherently higher fault tolerant capabilities when compared with the switched-flux one. To the point of view of demagnetisation withstand capability, the doubly salient topology stands out as the most robust one while the switched flux is the weakest one. [ABSTRACT FROM AUTHOR]

In this study, a novel partitioned stator hybrid excited machine is proposed, in which the excitation sources including both permanent magnets (PMs) and field windings are allocated on the secondary stator that is separated from the original stator having armature windings. As a result, the available space is boosted to improve the torque density and flux regulation capability. Meanwhile, the rotor is simple without coil or PM. The PMs on the stator is placed on the slot openings between the two neighbour tooth tips, with which the uncontrolled voltage of the proposed machine is limited and it is favoured for safety-critical applications. The machine topology and operating principle are introduced in detail, and the basic electromagnetic performance is evaluated based on finite element method to validate the analysis. [ABSTRACT FROM AUTHOR]

This study proposes a new three‐phase dual‐rotor middle‐stator brushless flux switching generator for 400Hz diesel‐driven aircraft ground power units. For the proposed machine, both field and armature windings are hosted in the stator in such a way that not only fulfils brushless structure, but also realises the flux switching function. Moreover, both windings have non‐overlapping concentrated windings to shorten the end‐windings and reduce the copper losses. In the meantime, the rotor has only slots without any active parts. First, the machine detailed design is provided, and its performance is analysed using finite element method. Also, a selection topology of both stator and rotor pole arcs is carried out, targeting maximum generated electromotive force, minimum harmonic content, and minimum cogging torque. Then, a prototype is implemented and experimented to confirm the feasibility of the proposed machine. [ABSTRACT FROM AUTHOR]

An integrated-starter-generator (ISG) system provides a cheap hybrid power strategy for hybrid electric vehicles (HEV). 12-10 flux switching integrated-starter-generator (FSISG) is one type of ISG machine, which employs the flux switching topological structure to improve the performance. In this paper, a prototype of 12-10 FSISG with the improved structure, which was employed to improve the manufacturability, was analyzed and studied. Through numerical studies, the influences of the improved structure and the characteristics of 12-10 FSISG were revealed. According to finite element analysis (FEA) results, the output voltage of FSISG can be considered as sinusoidal voltage. The results of the output torque show that the excitation current density of FSISG should be limited to less than 9 A/mm2 to avoid serious magnetic saturation. Next, the experimental tests of the prototype were carried out on the testing platform. In generating mode, the experiment results indicate that FSISG can output electrical energy with high efficiency in wide speed and torque ranges. In starting mode, the maximum starting torque of the prototype is 10.5 Nm. During the starting procedure, the prototype reaches a steady state rapidly. In the variable load conditions, it shows a rapid response ability to the changes of loads. According to the experiment results in this paper, the 12-10 FSISG has shown a promising performance for HEV application in both generating mode and starting mode. [ABSTRACT FROM AUTHOR]

In this paper, an U-shape flux barrier rotor concept for a hybrid excited synchronous machine with flux magnetic bridges fixed on the rotor is presented. Using 3D finite element analysis, the influence of axial flux bridges on the field-weakening and -strengthening characteristics, electromagnetic torque, no-load magnetic flux linkage, rotor iron losses and back electromotive force is shown. Three different rotor designs are analyzed. Furthermore, the field control characteristics depending on additional DC control coil currents are shown. [ABSTRACT FROM AUTHOR]

This study presents magnetic equivalent circuit (MEC) model of ring winding axial flux machine (AFM). The ring winding AFM is a new permanent magnet topology that presents many advantages like reliability, simple construction, low cost and ease of increasing pole and phase numbers. For optimal design of this new type of machine, a fast and accurate performance analysis tool is needed. In this regard, MEC model of the ring winding AFM is proposed. It is shown that the developed MEC model of the ring winding AFM provides very fast solution, yet accurate results compared with three‐dimensional finite‐element model (3D FEM). The proposed MEC model considers 3D geometry, magnetic saturation, leakage fluxes and rotor position. Furthermore, this study provides equations to consider fringing flux between arc segmented surface mounted permanent magnets and stator teeth. Experimental and 3D FEM results are employed to show the validity of the proposed MEC model. [ABSTRACT FROM AUTHOR]

This study investigates the influence of rotor topologies and winding configurations on the electromagnetic performance of three‐phase synchronous reluctance machines (SynRM) with different slot/pole number combinations, e.g. 12‐slot/4‐pole and 12‐slot/8‐pole. Transversally laminated synchronous reluctance rotors with both round flux barrier and angled flux barrier have been considered, as well as the doubly salient (DS) rotor as that used in switched reluctance machines. Both concentrated and distributed winding configurations are accounted for, i.e. single‐layer and double‐layer conventional and mutually coupled windings, as well as fully pitched winding. The machine performance in terms of d‐ and q‐axis inductances, on‐load torque, copper loss, and iron loss have been investigated using 2D finite‐element analysis. With appropriate rotor topology, 12‐slot/4‐pole and 12‐slot/8‐pole machines with fully pitched and double‐layer mutually coupled windings can achieve similar torque capacity, which are higher than the machines with other winding configurations. In addition, the synchronous reluctance machine with round flux barrier can have lower iron loss than DS reluctance machine under different working conditions. The prototypes of 12‐slot/8‐pole single layer and double layer, DS SynRM have been built to validate the predictions in terms of inductances and torques. [ABSTRACT FROM AUTHOR]

Hybrid excitation synchronous machines (HESMs) are permanent magnet machines which allow the control of the air‐gap flux density. In this study, three new axial field HESM structures, each having two rotors and one stator, are proposed. The operation principles of these machines, considering weakening or supporting the air‐gap flux density, are described. The magnetostatic and transient analyses of the proposed models have been carried out by using finite element method. To have reliable analysis results, the stator length and input and output diameters of the models have been chosen to be identical. Results are compared in terms of efficiency, power density and range of flux control between each other and another axial field HESM in the literature. In conclusion, the proposed HESM models demonstrate satisfactory performance for the generator mode and they are suitable for wind energy applications. Furthermore, because of their field weakening operation ability they can be used as motors in the vehicle industry. [ABSTRACT FROM AUTHOR]

The irreversible magnet demagnetisation phenomena are investigated, under both healthy and short‐circuit conditions for a switched flux permanent magnet (SFPM) machine. The temperature effects on permanent magnet material are taken into account and the influence of short‐circuit current over demagnetisation is evaluated. To calculate the short‐circuit current (mainly inter‐turn short circuit), the MATLAB/Simulink model has been employed. The aforementioned short‐circuit current is then fed to the finite‐element model, so the demagnetisation analysis can be carried out. Various fault scenarios are investigated, including a high speed and high fault severity. It is found that the short‐circuit current has limited effect on the magnet demagnetisation due to particular features of the SFPM machines. The mechanism of demagnetisation has been revealed and found out to be mainly due to temperature rise and poor PM materials utilisation. Experiments have been carried out to validate the MATLAB/Simulink model for short‐circuit current predictions. [ABSTRACT FROM AUTHOR]

The paper presents three novel rotor design concepts for a three-phase electric controlled permanent magnet synchronous machine (ECPMS-machine) with hybrid excitation. The influence of magnets and flux-barriers arrangement on the magnetic field distribution and field-weakening characteristics of the machine is examined, based on a three-dimensional finite element analysis (3D-FEA). Moreover, a prototype rotor design based on a new rotor concept with a good field-weakening capability is presented in detail. Finally, the experimental results of no-load back electromotive force (back-EMF) waveforms and field-weakening characteristics versus a control coil current of the machine are reported. [ABSTRACT FROM AUTHOR]

This study presents a design methodology for a newly emerged switched‐flux memory machine with low‐cost non‐rare‐earth. The adoption of aluminium–nickel–cobalt magnet with low‐coercive force enables the flexible air‐gap flux control without unnecessary excitation loss. Hence, the excellent flux variability and high‐efficiency sustainability within a wide‐speed range can be achieved. Since geometric constraints exist among major parameters, a design trade‐off should be established to facilitate the feasible design. Therefore, a simplified magnetic circuit is modelled to analytically determine the relationships among various parameters, and the generic design considerations including magnet grade selection and stator/rotor‐pole combination are addressed, respectively. The influences of design parameters on back‐electromotive force and torque capability are evaluated to aid the performance optimisation. A machine prototype is then fabricated to experimentally validate the theoretical analyses. [ABSTRACT FROM AUTHOR]

In this paper, a correction method is introduced to make a more accurate calculation of winding eddy‐current losses of high‐voltage direct current (HVDC) converter transformer. The assumption that winding eddy‐current losses of HVDC converter transformers follow the frequency with the exponent 2 proposed by IEC 61378‐2 Std. is thought to be inappropriate and the skin effect should be taken into consideration. The frequency characteristic of winding eddy‐current losses is proposed by analysing the distribution of magnetic flux in conductors, in which skin effect is taken into consideration. The correction method with a correction factor is then introduced to correct the assumption. To verify the validity of the correction method, a two‐dimension axisymmetric finite element analysis of a HVDC converter transformer is conducted. The geometrical complexity of windings and electrical connection are fully taken into account, it is shown that the correction method shows a significant advantage. Influence of different methods is revealed by applying the actual non‐sinusoidal load current and it is shown that the error of correction method is the least. At last, harmonic losses measurements are conducted on three coils to investigate the limits of the correction method. [ABSTRACT FROM AUTHOR]

This paper presents a finite simulation model of the hybrid excitation synchronous machine taking into consideration the saturation effect, the iron losses and including higher‐order electromagnetic force harmonics. Simulation and experimental testing prove that the advanced model represents more accurately the machine especially when compared with the basic Park model built with sinusoidal waveform assumption. The main contribution of the work is that only few experimental measurements are needed in order to implement the advanced model. [ABSTRACT FROM AUTHOR]

This paper proposes a novel integrated brushless excitation method (IBEM) for a rotor‐excited generator. IBEM is applied to a rotor‐excited hybrid excitation synchronous generator (HESG) to realise brushless excitation while the key features of the rotor‐excited generator are maintained. The new generator is referred as IBE HESG here. The stator excitation windings are buried in the stator slots. The static excitation field is established in the air gap when there is dc excitation current in the stator excitation windings. The three‐phase armature coils of the rotor induce the static excitation field and provide the dc excitation current for the rotor excitation windings via a rotating rectifier. The operating principles are discussed theoretically. The magnetic field distribution and the operating characteristics are studied by finite‐element analysis. The no‐load, external, regulation and excitation characteristics are analysed. Compared with the brush excitation HESG, the rotor excitation current is able to meet the requirement and the output voltage is conveniently regulated by the stator excitation current. Finally, a 1.5 kVA prototype is fabricated to test the operating characteristics of IBE HESG. It demonstrates that the brushless excitation is realised and the output voltage is regulated by the stator excitation current. [ABSTRACT FROM AUTHOR]

Hybrid excited axial field flux‐switching machine (HEAFFSM) with permanent magnets (PMs) and excitation windings in its stator is a novel hybrid excited flux‐switching PM machine. The HEAFFSM combines the advantages of the hybrid excited synchronous machine and flux‐switching PM machine. In this study, the topology and operating principles of the HEAFFSM are analysed, and the electromagnetic characteristics (including the winding inductances, flux, and cogging torque) are obtained by the three‐dimensional finite‐element method. On the basis of the vector control method, the mathematical model of the HEAFFSM is deduced, and the operating performance of the HEAFFSM across its entire operating range is investigated. A new minimum‐copper‐loss (MCL) control strategy for the HEAFFSM drive system, which can operate in both flux‐enhancing and flux‐weakening conditions, is proposed and compared with the traditional control. The experimental results demonstrate that the MCL strategy maximises the range of speed regulation while minimises the copper loss of the HEAFFSM drive system. Moreover, the flux‐regulation capability and high power/torque density of the HEAFFSM are validated. [ABSTRACT FROM AUTHOR]

In this study, a mechanical flux adjusting technique for the switched flux permanent magnet (SFPM) machines is presented to improve the flux‐weakening capability by extending the speed range. The ferromagnetic material pieces, that is, flux adjusters (FAs), are located on the outside surface of the stator poles equipped with permanent magnet (PM) and used to weaken the PM flux via short‐circuit. To explore the most suitable machine topologies for such flux adjusting technique, the performance of conventional SFPM machines with different stator/rotor pole combinations, multi‐tooth, E‐core and C‐core SFPM machines is investigated and compared by employing the FAs. It shows that the maximum speed and flux‐weakening capability of the conventional SFPM machines can be significantly increased if the FAs are used. On the other hand, the multi‐tooth, E‐core and C‐core SFPM machines have inherently large inductance. Thus, the flux adjusting technique has less influence on their flux‐weakening performance. Besides two‐dimensional (2D) finite‐element analysis (FEA) and analytical methods, 3D FEA accounting for end‐effect is also used to predict the results. Finally, the analyses are validated by experiments. [ABSTRACT FROM AUTHOR]

This paper presents two novel designs of magnetic flux‐modulated mnemonic (MFMM) machines which incorporate magnetic gearing effect and flux‐mnemonic concept together. Both of these two machines can perform large torque production at low‐speed because of the magnetic gearing effect, and can readily achieve flexible flux‐controllability by temporarily applying current pulses to magnetise/demagnetise aluminium‐nickel‐cobalt magnets so as to expand the constant‐power region operation effectively. One machine has permanent magnets (PMs) on its rotor and outer stator which is referred as the dual‐layer PM MFMM (DPM‐MFMM) machine; bi‐directional field modulating effect is artfully incorporated in this machine to guarantee effective coupling between the magnetic fields excited by the armature windings and those excited by the two sets of PMs. The second machine employs all the PMs on the outer stator and the rotor is only made up of ferromagnetic segments. In other words, it is a single‐layer PM‐MFMM (SPM‐MFMM) machine, and the rotor carries the flux modulating poles. The configurations and working principles of both machines are discussed. The electromagnetic performances are comprehensively studied and quantitatively compared using finite element method (FEM). [ABSTRACT FROM AUTHOR]

A novel switched flux permanent magnet machine (SFPMM) with both normal NdFeB and low coercive force (LCF) magnets has been developed in this paper. Outside a conventional SFPMM, the LCF magnets are mounted on the back of every U‐shaped stator lamination segment with parallel magnetisation direction and alternative polarities. A lamination ring yoke is placed around all the LCF magnets, while extra magnetisation coils are wound on each of them. By injecting different directions of current pulses into the magnetisation coils, the polarities of the LCF magnets can be rewritten in order to enhance or weaken the field generated by normal NdFeB magnets. Therefore the back EMF and torque capability could be adjusted in a wide range. In this paper, the operation principle and machine topology are introduced firstly. Then the stator/rotor pole combinations and design considerations of the machine have been discussed. With the help of two‐dimensional finite element software, a 6/5 stator/rotor pole machine has been globally optimised as an example to show the machine performances such as open‐circuit field and back EMF, dq‐axis inductances, torque capabilities and magnetisation. Finally, a prototype with the same dimensions has been manufactured and tested to validate the analysis results. [ABSTRACT FROM AUTHOR]

This paper presents an optimization analysis of an axial flux‐switching hybrid excitation synchronous machine (AFHESM) to improve its no‐load electromagnetic performances. The shapes of permanent magnet (PM), rotor‐teeth and stator slot of AFHESM are investigated for a better design scheme by finite element analysis (FEA). Some optimal results under no‐load are achieved, which mainly including the induced electromotive force (EMF), cogging torque and field control ability. Both FEA and experimental results show that the induced EMF can be improved when PM shape coefficient is 0.95 and the rotor‐teeth bevel angle is 6°. [ABSTRACT FROM AUTHOR]

This study presents a novel switched reluctance machine (SRM) with modular E‐core stators and multi‐layer common rotors for high reliability applications. The stator is composed of six independent modular E‐cores with the windings wound around the yoke of the E‐cores. The rotor consists of three magnetically independent common rotors which are place in the same shaft without any angular shift. The equivalent magnetic circuit (EMC) models of this new SRM at the aligned and unaligned positions are described. To evaluate the motor performance, two types of analysis, namely, approximate simplified two‐dimensional (2D) model and 3D model finite‐element analysis (FEA) have been utilised. The 2D FEA static and dynamic results are compared with 3D FEA results. Furthermore, comparisons between the novel modular SRM and a conventional 6/4 SRM are made. Finally, a prototype of this modular SRM has been fabricated and tested in the laboratory. Comparison between FEA and EMC analysis for flux linkage are made and compared with measured characteristics. The simulated and measured phase currents and average torque are also presented and compared to verify the analytical and simulation results. [ABSTRACT FROM AUTHOR]

Purpose – The purpose of this paper is to propose an optimization method by combining artificial immune algorithm and finite element analysis to find the optimal exciting electrode of a piezoceramic plate type ultrasonic motor vibrator. Design/methodology/approach – The artificial immune algorithm is selected as optimizer for its merit of fast convergence to global optimal solution. The finite element analysis is used to calculate the motion trajectory of contact point. The objective function is the work that the vibrator does to rotor. The design variables are the boundaries of exciting electrode on piezoceramic plate vibrator surface. Findings – The calculated results and the experimental results show that using this method, both the position and the size of optimal exciting electrode of this ultrasonic motor can be quickly and accurately determined. Originality/value – In order to successfully design an ultrasonic motor, both the position and the size of the exciting electrode must be investigated, so as to change more electric energy into mechanical energy. In this paper, an optimization method by combining artificial immune algorithm and finite element analysis is proposed for the exciting location optimization of a piezoceramic plate type ultrasonic motor to obtain large power output. [ABSTRACT FROM AUTHOR]

In this paper, a nonlinear magnetic network model (NMNM) is proposed to predict the electromagnetic performance of a hybrid-excitation flux-switching (HEFS) machine, in which the modeling of the magnetic motive forces (MMF) due to field windings is specifically investigated. The proposed NMNM enables the predictions of air-gap flux-density distributions, flux linkage, back-electromotive force (back-EMF), and inductances of both armature and field windings under different excitation conditions, including pure magnets, pure field currents, and hybrid excitations. The predicted results from the NMNM model are validated by 2-D finite element analysis. [ABSTRACT FROM AUTHOR]

A new Single-sided Variable Flux Permanent Magnet Linear Machine with flux bridge in mover core is proposed in this paper. The flux bridge prevents the leakage flux from the mover and converts it into flux linkage, which greatly influences the performance of the machine. First, a lumped parameter model is used to find the suitable coil combination and no-load flux linkage of the proposed machine, which greatly reduces the computational time and drive storage. Secondly, the proposed machine replaces the expensive rare earth permanent magnets with ferrite magnets and provides improved flux controlling capability under variable excitation currents. Multivariable geometric optimization is utilized to optimize the leading design parameters like split ratio, stator pole width, width and height of permanent magnet, flux bridge width, the width of mover's tooth, and stator slot depth at constant electric and magnetic loading. The optimized design increases the flux linkage by 44.11%, average thrust force by 35%, thrust force density by 35.02%, minimizes ripples in thrust force by 23%, and detent force by 87.5%. Furthermore, the results obtained by 2D analysis are verified by 3D analysis. Thermal analysis is done to set the operating limit of the proposed machine. [ABSTRACT FROM AUTHOR]

Torque density is one of the major limiting factors in machine design. In this paper, we propose the hybrid excited partitioned stator switched flux machine3 (HE-PSSFM3). In HE-PSSFM3, armature winding is positioned on the outer stator whereas the permanent magnet (PM) and field winding are placed at the inner stator, while the rotor is free from excitation sources and armature winding. Moreover, concentrated field winding is replaced by toroidal winding. The power splitting ratio between two stators/rotor pole combinations is analytically optimized and are validated through genetic algorithm (GA) in order to enhance average torque and flux regulation capability. The electromagnetic characteristics of the improved and initial design are evaluated and compared with existing designs, i.e., HE-PSSFM1 and HE-PSSFM2. The proposed HE-PSSFM3 has achieved high average torque, i.e., 2.0015 Nm, at same armature and field current densities of 5 A/mm 2 . The results show that the average torques of the proposed design are 35% and 15% greater than HE-PSSFM1 and HE-PSSFM2, respectively. Furthermore, the analysis of various parameters such as flux linkage, flux regulation, electromagnetic performances, cogging torque, back EMF, electromagnetic torque, and torque ripples are investigated using two dimensional (2D) finite element analysis (FEA). Moreover, the simulation results of the proposed design are validated through GA and analytical modeling. [ABSTRACT FROM AUTHOR]

This paper presents the control of a Switched Reluctance Generator (SRG) for low voltage DC grid with the objective of efficiency maximizing. Analysis of the energy conversion, including electrical machine losses (Joule, magnetic, mechanical) and power converter losses (switching and conduction), has shown that there is an optimal combination of control variables (turn-on and conduction angles, phase current reference), which maximizes the drive efficiency. The control variables are derived from a Finite Element Analysis and parametric optimization algorithm for all of the operating points in the torque-speed plane and stored in lookup tables. The performances are evaluated with intensive numerical simulations and experimental tests with a 8/6 SRG feeding a DC resistive load for different rotational speeds. The results show good performances of the output DC voltage control with low ripples, even in the presence of speed and load variations. Thanks to the optimization, simulation results show that beyond 1500 rpm, drive efficiency is higher than 60 % and almost reaches 70 % at nominal speed. The experimental results show that, for light loads and beyond rated speed, the drive efficiency lies in the range between 60 % and 80 % . [ABSTRACT FROM AUTHOR]

Accurate calculation of the vibration mode and natural frequency of a motor stator is the basis for reducing motor noise and vibration. However, the stator core and winding material parameters are difficult to determine, posing issues which result in modal calculation bias. To address the problem of calibrating the stator material parameters, we developed a parameter correction method based on modal frequency. First, the stator system was simplified to build a stator system finite element model. Secondly, the relationship between modal frequency and material parameters was analyzed by finite element software, the relationship between modal frequency and material parameters was derived, and the anisotropic material parameter correction method was summarized. Finally, a modal experiment was carried out by the hammering method, and the simulation and experimental errors were within 3%, which verified the accuracy of the finite element model. The proposed correction method of anisotropic material can quickly determine the stator material parameters, and the stator core and winding anisotropic material can ensure the accuracy of the modal analysis. [ABSTRACT FROM AUTHOR]