Trapezoid BackEMF Waveform Prediction of IPM BLDC Motor Based on Neural Network
YoungYoon Ko^{1}, Wonseok Han^{1}, Do Hyun Kang^{1}, SeungGu Kang^{1}, YongJae Kim^{2}, SangYong Jung^{1}
^{1}Sungkyunkwan University, Korea, Republic of (South Korea); ^{2}Chosun University, Korea, Republic of (South Korea)
In this paper, the trapezoid back electromotive force (EMF) waveform of Itype interior permanent magnet (IPM) brushless DC (BLDC) motor is predicted using analytical methods and neural network (NN). At first, analytical methods, magnetic equivalent circuit and conformal mapping, are applied to calculate accurate backEMF waveform for the given data of NN. Secondly, kfold cross validation, one of NNs, is conducted to train the backEMF approximation function. Finally, the reliable trapezoid backEMF is derived from NN with unknown input data. The accuracy of the proposed method is verified by comparing backEMF result with experiment result of final model. The 4pole 6slot model is applied.
Magnetic Integration Design and Analysis for the Hybrid Distribution Transformer
Yibin Liu, Deliang Liang, Shaofeng Jia, Shuaijun Chu, Shengliang Cai, Zhichao Chen, Mingkang Zhang
Xi’an Jiaotong University, China, People's Republic of
Hybrid distribution transformer (HDT) has powerful controllability, and it is greatly useful for the development of the future smart grid. However, the large numbers of discrete magnetics in HDT will lead to a waste of the magnetic material, In this paper, a magnetic integration structure of HDT (IMHDT) is proposed, which is realized by inserting the leakage magnetic iron cores, sharing the common magnetic circuits. All the transformers and inductors are integrated together in IMHDT, and its integration principles are analyzed. The magnetic flux phasor diagrams and the finite element analysis (FEA) simulation results are obtained, which indicate the validity of the proposed IMHDT.
Analysis on Vernier Motor with Modular Winding considering Rotor Eccentricity
DaeWoo Kim^{1}, Do Hyun Kang^{1}, JinSeok Kim^{1}, YongJae Kim^{2}, SangYong Jung^{1}
^{1}Department of Electronic and Computer Engineering, Sungkyunkwan University, Suwon, Korea, Republic of Korea; ^{2}Department of Electrical Engineering, Chosun University, Gwangju, Republic of Korea
In this paper, the flux modulation pole (FMP) type vernier motor with modular winding is analyzed considering the rotor eccentricity. As the FMP type vernier motor utilizes flux modulation, it is able to achieve high torque density that is adequate for the lowspeed hightorque applications despite of its configuration complexity. However, rotor eccentricity generates unbalanced radial force, causing issues such as noise and vibration during its operation. Therefore, operation characteristic of the FMP type vernier motor is studied regarding rotor eccentricity, and methods to alleviate its side effects are suggested. To begin with, the operation characteristic of the vernier motor is introduced. Then, the FMP type vernier motor with modular winding is analyzed using the finite element method, where its load and noload conditions are studied. Then, different methods, such as redistribution of stator winding and variation of design parameters are employed to alleviate undesired symptoms due to rotor eccentricity. To conclude, the operation characteristics of base and suggested method employed models are compared to verify its effectiveness in reducing deficiency caused by rotor eccentricity.
Effect of Core Structure on Iron Loss and Deformation of ThreePhase Reactor with Anisotropic Iron Core
Yanhui Gao^{1}, Shuhei Ichimaru^{1}, Toshihisa Miyabe^{1}, Mohendro Kumar Ghosh^{1}, Daisuke Kusano^{1}, Hiroshi Dozono^{1}, Kazuhiro Muramatsu^{1}, Weimin Guan^{2}, Jiaxin Yuan^{2}, Cuihua Tian^{2}, Baichao Chen^{2}
^{1}Saga University, Japan; ^{2}Wuhan University, P. R. C.
To investigate the iron loss and noise reduction methods of a threephase reactor composed of anisotropic iron cores, the effect of different core structures on the iron loss and noise are evaluated by using the magnetic field and mechanical analyses in this paper. In these analyses, the anisotropic magnetic characteristics of the BH curve, iron loss curve, and magnetostriction in arbitrary direction are considered. The iron loss and displacement of three kinds of core structures, namely, brick anisotropic cores only, obliquejoint cores, and hybrid of anisotropic and isotropic brick cores, are obtained and compared. It is shown that the last core structure is attractive because the displacements can be reduced without increase of iron loss compared with the other two core structures.
Modeling of Dynamic Torque Control of a Coaxial Magnetic Gear
Iliana Marinova, Valentin Mateev
Technical University of Sofia, Bulgaria
Overload of magnetic gears effects in output rotor slipping which reduce its speed and torque. Here is presented a dynamic model of a control system to avoid overload and keep optimal power transmission between rotors of a coaxial magnetic gear. The dynamic model couples transient finite element magnetic model with control unit with input/output measuring sensor. Input and output rotational speeds, torques and air gap magnetic fluxes are dynamically acquired to optimize the power transmission. Control function is trained over a coaxial magnetic gear modeling.
Comparative Analysis of Ferrite PMSGs Based on Optimal Designs
José Fabio Kolzer^{1}, Thiago De Paula Bazzo^{1}, Renato Carlson^{2}, Frédéric Wurtz^{3}
^{1}Federal University of Technology – Paraná, Brazil; ^{2}Federal University of Santa Catarina, Brazil; ^{3}G2Elab, Grenoble Alpes University, Grenoble, France
This paper presents a performance analysis of four topologies of permanent magnet synchronous generators (PMSG) generating power for a 3 kW, 220 V, threephase, Yconnected resistive load, based on a methodology for the optimal design of PMSG using ferrite permanent magnets. The optimal designs of the machines, intended to small wind turbines, use multidisciplinary optimization models and a deterministic algorithm. As high power density is desired, only flux concentration topologies that allow high values of magnetic induction in the air gap were proposed, including inner and outer rotor machines, as well as conventional and vernier topologies. For the inner rotor conventional machines, both an integer and a fractional number of slots per pole per phase were proposed. The other two machines considered in this paper were a conventional radial flux machine and a vernier machine, both of them with outer rotor and fractional number of slots per pole per phase. After validation of each optimal design by a finite element software, the more convenient pole number for each topology was identified, observing that the vernier machine presented the lowest torque ripple, the highest power density and the lowest active material cost among the four topologies of PMSGs.
The Method of Torque and Iron Loss Calculation for Computing Efficiency Map according to Design Variables
SungBae Jun^{1}, SangHyeok Seo^{1}, YongJae Kim^{2}, SangYong Jung^{1}
^{1}Sungkyunkwan University, Korea, Republic of (South Korea); ^{2}Chosun University, Korea, Republic of (South Korea)
In this paper, the research for computing efficiency map by calculating iron loss of interior permanent magnet synchronous motor(IPMSM) is carried out to reduce analyzing time. For this research, the efficiency map of base model is computed by finite elements analysis(FEA), then iron loss resistance Rc can be calculated. The iron loss resistance Rc is expressed as a function of spatial flux density and frequency. After computing this function, the spatial flux density of motor is extracted according to design variables, and iron loss and efficiency of new model can be easily calculated by the function.
Modeling and Electromagnetic Performance Analysis of DoubleSided NegativeSaliency Axial Flux Permanent Magnet Motors
Wenming Tong, Shanhong Dai, Shengnan Wu
Shenyang University of Technology, China, People's Republic of
This paper proposes an analytical model of negativesaliency axial flux permanent magnet motors with the doublesided topological structure. The presented analytical model is based on the subdomain method combining the airgap relative permeance coefficient, which is determined by the magnetic equivalent circuit method. In the same time, the slotting effect is considered by MEC method. The analytical model is adopted to study the influence of different soft iron structures on the electromagnetic performance of axial flux permanent magnet motors. The finite element analysis and analytical calculation results are presented for verifying the accuracy of the proposed analytical model.
Analytical Modeling for Magnet Loss in Axial Flux PMSM with Different SlotPole Combinations
Wenming Tong, Boyu Cao, Shengnan Wu
Shenyang University of Technology, China, People's Republic of
This paper proposes an analytical model to analyze the magnet loss of axial flux permanent magnet synchronous machines with different slotpole combinations considering magnet eddy current reaction. The magnetic field in the magnets is obtained by solving Maxwell’s equations in subdomains. The slot opening coefficient is taken into consideration. The magnet loss is calculated using a resistance network. This calculation results of the magnet loss and its distribution are obtained when the motor is with different slotpole combinations and under the ideal noload condition and rated load inverterfed condition, respectively. The magnet loss of the motor caused by each time harmonic induced by the inverter is calculated with different slotpole combinations under rated load inverterfed condition. The analytical model is verified by the comparison with the finite element calculation results.
Investigation of Torque Characteristics of Switched Flux Hybrid Magnet Memory Machine by a Coupled Solution
Hui Yang^{1}, Heyun Lin^{1}, Z. Q. Zhu^{2}, Ling Qin^{1}
^{1}Southeast University, China, People's Republic of; ^{2}The University of Sheffield, UK
This paper investigates the torque characteristics of switched flux hybrid magnet memory machine (SFHMMM) by employing a coupled solution combining a quasilinear hysteresis model (QLHM) of low coercive force (LCF) magnet and frozenpermeability method (FPM). The QLHM is utilized to characterize the repetitive remagnetizing/demagnetizing behaviors of LCF PMs, while the FPM is employed to separate and quantify the torque contributions due to NdFeB/LCF PMs and armature windings. Consequently, this paper provides a powerful insight into the torque generation mechanism and design guidelines of SFHMMM. The machine topology and analysis methodology are described, respectively. The torque segregation results accounting for magnetization state (MS) variation are analyzed by the proposed coupled solution. Finally, the prototype is tested to experimentally validate the theoretical analysis.
Computation and Experimental Verification of the Dynamic Characteristics of Transformer Windings under Short Circuit Fault
Shuhong Wang, Shuang Wang, Song Wang, Hao Qiu, Ting Zhu
Xi'an Jiaotong University, China, People's Republic of
The dynamic characteristics for a 35 kV power transformer under the short circuit condition is computed through the magnetic–structural coupling analysis. The dynamic stress, acceleration, and displacement of the windings due to the short circuit fault are obtained. The distribution characteristics and change rule of the winding stress and displacement are analyzed. The short circuit experiment is conducted to verify the accuracy of the calculation method and results. Dynamic characteristics of the transformer windings are measured using the optical fiber measurement system and highspeed camera. The dynamic process and mechanical behavior of the windings under the action of the electromagnetic force during the short circuit fault are revealed.
Design and ElectricMechanical Performance Analysis of High Speed Noncontact Magnetic Gear for Low Gear Ratio Applications
DoKwan Hong^{1,2}, TaeWoo Lee^{1,2}, JungHwan Chang^{3}
^{1}Korea Electrotechnology Research Institute, Korea, Republic of (South Korea); ^{2}University of Science & Technology, Korea, Republic of (South Korea); ^{3}DongA University, Korea, Republic of (South Korea)
Noncontact magnetic gear consists of outer rotor part, pole piece part, inner rotor parts and bearings and so on. KERI (Korea Electrotechnology Research Institute) is developing and focusing on a surface permanent magnet (SPM) type of noncontact magnetic gear. This technology virtually improves power density and torque density considering combinations such as inner pole pairpole pieceouter pole pair. The electrical and mechanical simulation result is well performed considering electrical loss estimated by magnetic analysis. The design, analysis and experiment of the SPM noncontact magnetic gear for low gear ratio applications have been developed successfully.
Prediction of NoLoad Flux Density Distribution in Interior Permanent Magnet Machines Based on Magnetic Equivalent Circuit
Wenming Tong, Shiqi Li, Ruolan Sun
Shenyang University of Technology, China, People's Republic of
A simplified magnetic equivalent circuit (MEC) model is presented for an interior permanent magnet (IPM) machine, using a motor with threephase distributed stator windings and V type permanent magnet in the rotor as an example topology. The model can take into account not only the effects of stator slots on the airgap flux distribution, but also the variation of magnetic saturation levels in the core. The model analyzes the variation trend of airgap flux density by the size change of magnetic bridge when the angle of V type PM is constant, special considerations are given at the stator tooth tips to improve the accuracy. Finite element analysis (FEA) results are presented that match the MEC results quite closely, building confidence in the model.
Analytical Modeling of Rotor Eddy Current Loss Radial Distribution of Permanent Magnet synchronous Motor with a Retaining Sleeve
Wenming Tong, Lu Sun, Shengnan Wu, Boyu Cao
Shenyang University of Technology, China, People's Republic of
This paper presents an analytical model for predicting the rotor loss of permanent magnet (PM) and the retaining sleeve in high speed surfacemounted permanent magnet synchronous motor with an amorphous metal stator core. The eddy current reaction，the permeability harmonic caused by stator slotting and uneven magnet eddy current loss distribution are considered in the model，which improves the calculation accuracy. The eddy current loss in PM and retaining sleeve can be calculated when the motor is supplied by the PWM. The radial distribution of the loss in PM is obtained by dividing PM into several circular fields along the radial direction. Then, the influence of different airgap length and the radial distribution of the loss in PM are calculated. Finally, the calculated results are verified by comparing with the finite element analysis.
Characteristic analysis of Interior Permanent Magnet Synchronous Motor by ventilation hole and temperature change
HongSik Lim, ByoungWook Jo, CheonHo Song, KiChan Kim
hanbat national university, Korea, Republic of (South Korea)
Because of the environmental pollution problem and the development of a rare earth magnet, research on IPMSM for Electric Vehicle (EV) s, which are ecofriendly automobiles, is actively under way. In this paper, the changes of electromagnetic field characteristics according to the temperature change of 20 ℃, 80 ℃, and 140 ℃ are compared and analyzed through Finite Element Method(FEM). In addition, for the high efficiency design of the motor, through FEM we propose the ventilation holes design, which reduces the temperature while keeping the output of the motor almost. As the result of FEM simulation, it was confirmed that the residual flux density increase and the winding resistance decrease due to the temperature decrease. Because of that, daxis and qaxis inductance, and magnetic flux linkage are changed. In particular, it was confirmed that phase current and angle of phase current, which are the control parameters of IPMSM, is not accurately controlled unless temperature is taken into account. In addition, at MTPA driving point the efficiency was improved according to temperature decrease, and at the field weakening point, the efficiency decreased as the temperature decreased. Finally, it was confirmed that the output can crease by drilling the ventilation hole considering the path of the magnetic flux through FEM simulation.
Analytical Modeling of Armature Magnetic Field and Synchronous Inductance Calculation for Axial Flux Motor
Wenming Tong, Ming Jing
Shenyang University of Technology, China, People's Republic of
In this paper, a twodimensional analytical model of a singlerotor doublestator axial flux permanent magnet motor (AFPMM) is established. Based on this, the armature reaction magnetic field and synchronous inductance are analytically calculated. The model is established in a Cartesian coordinate system. The scalar magnetic position is adopted as the solution variable, and the Laplace equation is established at the slot opening, the air gap and the permanent magnet region respectively, and the boundary conditions between the subdomains are used to solve the equation, thus to obtain the distribution of the armature reaction field. The analytical model considers the effect of stator slotting on the armature reaction magnetic field by using the slot relative permeability coefficient. Based on the analytical model, the synchronous inductances of the motor with different poleslot combinations are solved and compared with the finite element and the prototype experimental results to verify the accuracy of the analytical model.
Influence of a Novel STIVCS on Air Gap Magnetic Flux Density and Stator Tooth Electromagnetic Force of Aircooled TurboGenerator
Wenmao Liu, Weili Li, Dan Li, Dong Li, Meiwei Zhang
Beijing Jiaotong University, China, People's Republic of
Opening an additional ventilation structure in the stator tooth of the generator is a new design method to directly improve the stator heat sinking capability of large aircooled turbogenerator. However, the structure will cause local magnetic flux saturation of the stator tooth and affect the air gap magnetic flux density (AGMFD), which in turn affects the generator performance and stator tooth electromagnetic force. Therefore, based on the research of a novel stator tooth internal ventilation cooling structure (STIVCS) of a large aircooled turbogenerator proposed in the previous stage, various models of global 2D electromagnetic field of the generator with different STIVCSs are established to study the influences of the position and aperture size of the structure on the radial and tangential AGMFD, and stator tooth electromagnetic force (STEF) of the generator. It provides a theoretical basis for the design of a new ventilation structure of large aircooled turbogenerator.
Reduction of Cogging Force and End Effect Analysis of a Linear Tubular Switching Permanent Magnet Machines.
Habibou Lawali Ali, Yacine Amara, Georges Barakat
University of Le Havre Normandie/ GREAH, France
The aim of this paper is to analyze the impact of cogging force and end effect on the performance of Linear Tubular Switching Permanent Magnet Machines (LTSPMM) using finite elements analysis and hybrid analytical model (HAM). The hybrid model is a direct coupling between analytical solution of Maxwell's equations and reluctance networks. To analyze the impact of cogging force and end effect on LTSPMM, many kind of topology of LTSPMM will be studied. First the study will start with two structures with periodic condition which means, end effects are not considered. And at the next time, the end effects will be considered .This way allows us to see how these effects have the impact on the performances of LTPMM by comparing the global performances of the structures with and without end effects. Finally at the end some solutions will be presented to show how to reduce both cogging force and end effects of LTSPMM in the order to have it good performance.
Double Star Permanent Magnet Synchronous Machine Losses Computation for Healthy Case and Under IGBT ShortCircuit Fault
AbedAlKader AlAsmar, Amina Bensalah, Ferhat Chabour, Georges Barakat, Yacine Amara
GREAH, France
This paper proposed the computation of the losses of a double star permanent magnet synchronous machine (DSPMSM) drive fed by two voltage source inverters in the healthy case and in an inverter switch (IGBT) short circuit fault case. This IGBT shortcircuit fault is handled by shortcircuiting the related star winding in order to allow a faulttolerant operation of the machine. The machine performances are computed by finite element (FE) simulations for a large amount of operating points in the two cases. Particularly, these FE simulations allow the estimation of copper losses and iron losses thanks to a dynamic hysteresis model (LS model). The machine magnetic losses are then compared in the healthy case and in the IGBT shortcircuit fault case. The results comparison helps to predict the machine thermal behavior and to evaluate its capability to tolerate this inverter switch shortcircuit fault.
