Conference Agenda

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Session Overview
PA-M1: Novel Computational Methods for Machines and Devices
Tuesday, 16/Jul/2019:
10:50am - 12:40pm

Session Chair: Claude Marchand
Session Chair: Nicolas Galopin
Location: Patio 44-55

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Trapezoid Back-EMF Waveform Prediction of IPM BLDC Motor Based on Neural Network

Young-Yoon Ko1, Wonseok Han1, Do Hyun Kang1, Seung-Gu Kang1, Yong-Jae Kim2, Sang-Yong Jung1

1Sungkyunkwan University, Korea, Republic of (South Korea); 2Chosun University, Korea, Republic of (South Korea)

In this paper, the trapezoid back electromotive force (EMF) waveform of I-type 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 back-EMF waveform for the given data of NN. Secondly, k-fold cross validation, one of NNs, is conducted to train the back-EMF approximation function. Finally, the reliable trapezoid back-EMF is derived from NN with unknown input data. The accuracy of the proposed method is verified by comparing back-EMF result with experiment result of final model. The 4-pole 6-slot 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

Dae-Woo Kim1, Do Hyun Kang1, Jin-Seok Kim1, Yong-Jae Kim2, Sang-Yong Jung1

1Department of Electronic and Computer Engineering, Sungkyunkwan University, Suwon, Korea, Republic of Korea; 2Department 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 low-speed high-torque 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 no-load 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 Three-Phase Reactor with Anisotropic Iron Core

Yanhui Gao1, Shuhei Ichimaru1, Toshihisa Miyabe1, Mohendro Kumar Ghosh1, Daisuke Kusano1, Hiroshi Dozono1, Kazuhiro Muramatsu1, Weimin Guan2, Jiaxin Yuan2, Cuihua Tian2, Baichao Chen2

1Saga University, Japan; 2Wuhan University, P. R. C.

To investigate the iron loss and noise reduction methods of a three-phase 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, oblique-joint 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 Kolzer1, Thiago De Paula Bazzo1, Renato Carlson2, Frédéric Wurtz3

1Federal University of Technology – Paraná, Brazil; 2Federal University of Santa Catarina, Brazil; 3G2Elab, 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, three-phase, Y-connected 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

Sung-Bae Jun1, SangHyeok Seo1, Yong-Jae Kim2, Sang-Yong Jung1

1Sungkyunkwan University, Korea, Republic of (South Korea); 2Chosun 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 Double-Sided Negative-Saliency 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 negative-saliency axial flux permanent magnet motors with the double-sided 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 Slot-Pole 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 slot-pole 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 slot-pole combinations and under the ideal no-load condition and rated load inverter-fed condition, respectively. The magnet loss of the motor caused by each time harmonic induced by the inverter is calculated with different slot-pole combinations under rated load inverter-fed 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 Yang1, Heyun Lin1, Z. Q. Zhu2, Ling Qin1

1Southeast University, China, People's Republic of; 2The University of Sheffield, UK

This paper investigates the torque characteristics of switched flux hybrid magnet memory machine (SF-HMMM) by employing a coupled solution combining a quasi-linear hysteresis model (QLHM) of low coercive force (LCF) magnet and frozen-permeability 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 SF-HMMM. 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 high-speed 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 Electric-Mechanical Performance Analysis of High Speed Non-contact Magnetic Gear for Low Gear Ratio Applications

Do-Kwan Hong1,2, Tae-Woo Lee1,2, Jung-Hwan Chang3

1Korea Electrotechnology Research Institute, Korea, Republic of (South Korea); 2University of Science & Technology, Korea, Republic of (South Korea); 3Dong-A University, Korea, Republic of (South Korea)

Non-contact 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 non-contact magnetic gear. This technology virtually improves power density and torque density considering combinations such as inner pole pair-pole piece-outer 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 non-contact magnetic gear for low gear ratio applications have been developed successfully.

Prediction of No-Load 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 three-phase 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 surface-mounted 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 air-gap 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

Hong-Sik Lim, Byoung-Wook Jo, Cheon-Ho Song, Ki-Chan 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 eco-friendly 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, d-axis and q-axis 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 two-dimensional analytical model of a single-rotor double-stator 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 sub-domains 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 pole-slot 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 Air-cooled Turbo-Generator

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 air-cooled turbo-generator. 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 air-cooled turbo-generator proposed in the previous stage, various models of global 2-D 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 air-cooled turbo-generator.

Reduction of Cogging Force and End Effect Analysis of a Linear Tubu-lar 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 Per-manent 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 Short-Circuit Fault

Abed-Al-Kader Al-Asmar, 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 short-circuit fault is handled by short-circuiting the related star winding in order to allow a fault-tolerant 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 short-circuit fault case. The results comparison helps to predict the machine thermal behavior and to evaluate its capability to tolerate this inverter switch short-circuit fault.

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