다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

Although the concept of variable-speed drives, based on utilization of multiphase machines, dates back to the late 1960s, it was not until the mid- to late 1990s that multiphase drives became serious contenders for various applications. These include electric ship propulsion, locomotive traction, electric and hybrid electric vehicles, ldquomore-electricrdquo aircraft, and high-power industrial applications. As a consequence, there has been a substantial increase in the interest for such drive systems worldwide, resulting in a huge volume of work published during the last ten years. An attempt is made in this paper to provide a brief review of the current state of the art in the area. After addressing the reasons for potential use of multiphase rather than three-phase drives and the available approaches to multiphase machine designs, various control schemes are surveyed. This is followed by a discussion of the multiphase voltage source inverter control. Various possibilities for the use of additional degrees of freedom that exist in multiphase machines are further elaborated. Finally, multiphase machine applications in electric energy generation are addressed.

Multiphase Electric Machines for Variable-Speed Applications

This paper describes a comparative study allowing the selection of the most appropriate electric-propulsion system for a parallel hybrid electric vehicle (HEV). This paper is based on an exhaustive review of the state of the art and on an effective comparison of the performances of the four main electric-propulsion systems, namely the dc motor, the induction motor (IM), the permanent magnet synchronous motor, and the switched reluctance motor. The main conclusion drawn by the proposed comparative study is that it is the cage IM that better fulfills the major requirements of the HEV electric propulsion

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Electric Motor Drive Selection Issues for HEV Propulsion Systems: A Comparative Study

The main objective of this two-part state-of-the-art paper called “Recent Advances in the Design, Modeling, and Control of Multiphase Machines” is to present latest contributions in the multiphase machines' field. The first part of this paper focuses on the recent progress in the design, modeling, and control, whereas the drive is in healthy operation. This second part presents relevant contributions in two not analyzed fields. The first is in relation with the use of the additional degrees of freedom of multiphase machines and the exploitation of their fault-tolerant capabilities without adding extra hardware. The second one analyzes multiphase generation, particularly in grid-connected wind energy conversion systems and stand-alone applications. Recent progresses are shown and open challenges and future research directions are discussed.

Recent Advances in the Design, Modeling, and Control of Multiphase Machines—Part II

Roadway-powered electric vehicles (RPEVs) are attractive candidates for future transportation because they do not rely on large and heavy batteries but directly and efficiently get power while moving along a road. The inductive power transfer systems (IPTSs) that have been widely used for the wireless powering of RPEVs are reviewed in this paper. The development history of the IPTS is tracked from the origin of the RPEV in the 1890s to the recent RPEV. Throughout its 100-year history, the size, weight, efficiency, air gap, lateral tolerance, electromagnetic force, and cost of the IPTS have been substantially improved, and now RPEVs are becoming more widely commercialized. Important milestones of the developments of the IPTS and RPEVs are summarized in this paper, focusing on recent developments of on-line electric vehicles that were first commercialized in 2013.

Advances in Wireless Power Transfer Systems for Roadway-Powered Electric Vehicles

Introduction 11 Scope 12 Features 13 Development of AFPM Machines 14 Types of Axial Flwr PM Machines 15 Topologies and Geometries 16 Rotor Dynamics 17 Axial Magnetic Field Excited by PMs 18 PM Eddy-Current Brake as the Simplest AFPM Brushless Machine 19 AFPM Machines versus RFPM Machines 110 Power Limitation of AFPM Machines Numerical Examples 2 Principles of AFPM Machines 21 Magnetic Circuits 211 Single-Sided Machines 212 Double-Sided Machines With Internal PM DiscRotor 213 Double-Sided Machines With Internal Ring-Shaped Core Stator 214 Double-Sided Machines With Internal Slotted Stator 215 Double-Sided Machines With Internal Coreless Stator 216 Multidisc Machines 22 Windings 221 Three-Phase Windings Distributed in Slots 222 Toroidal Winding 223 Coreless Stator Winding 224 Non-Overlap (Salient Pole) Windings 23 Torque Production 24 Magnetic Flux 25 Electromagnetic Torque and EMF 26 Losses and Efficiency 261 Stator Winding Losses 262 Stator Core Losses 263 Core Loss Finite Element Model 264 Losses in Permanent Magnets 265 Rotor Core Losses 266 Eddy Current Losses in Stator Conductors 267 Rotational Losses 268 Losses for Nonsinusoidal Current 269 Efficiency 27 Phasor Diagrams 28 Sizing Equations 29 Armature Reaction 210 AFPM Motor 2101 Sine-Wave Motor 2102 Square-Wave Motor 211 AFPM Synchronous Generator 2111 Performance Characteristics of a Stand Alone Generator 2112 Synchronization With Utility Grid Numerical Examples 3 Materials and Fabrication 31 Stator Cores 311 Nonoriented Electrical Steels 312 Amorphous Ferromagnetic Alloys 313 Soft Magnetic Powder Composites 314 Fabrication of Stator Cores 32 Rotor Magnetic Circuits 321 PM Materials 322 Characteristics of PM Materials 323 Operating Diagram 324 Permeances for Main and Leakage Fluxes 325 Calculation of Magnetic Circuits With PMs 326 Fabrication of Rotor Magnetic Circuits 33 Windings 331 Conductors 332 Fabrication of Slotted Windings 333 Fabrication of Coreless Windings Numerical Examples 4 AFPM Machines With Iron Cores 41 Geometries 42 Commercial AFPM Machines With Stator Ferromagnetic Cores 43 Some Features of Iron-Cored AFPM Machines 44 Magnetic Flux Density Distribution in the Air Gap 45 Calculation of Reactances 451 Synchronous and Armature Reaction Reactances 452 Stator Leakage Reactance 46 Performance Characteristics 47 Performance Calculation 471 Sine-Wave AFPM Machine 472 Synchronous Generator 473 Square-Wave AFPM Machine 48 Finite Element Calculations Numerical Examples 5 AFPM Machines Without Stator Cores 51 Advantages and Disadvantages 52 Commercial Coreless Stator AFPM Machines 53 Coreless Stator AFPM Microgenerators 54 Performance Calculation 541 Steady-State Performance 542 Dynamic Performance 55 Calculation of Coreless Winding Inductances 551 Classical Approach 552 FEM Approach 56 Performance Characteristics 57 Performance of Coreless Non-Overlap Winding AFPM Machines 58 Eddy Current Losses in the Stator Windings 581 Eddy Current Loss Resistance 582 Reduction of Eddy Current Losses 583 Reduction of Circulating Current Losses 584 Measurement of Eddy Current Losses 59 Armature Reaction 510 Mechanical Design Features 5101 Mechanical Strength Analysis 5102 Imbalanced Axial Force on the Stator 511 Thermal Problems Numerical Examples 6 AFPM Machines Without Stator and Rotor Cores 61 Advantages and Disadvantages 62 Topology and Construction 63 Air Gap Magnetic Flux Density 64 Electromagnetic Torque and EMF 65 Commercial Coreless AFPM Motors 66 Case Study: Low-Speed AFPM Coreless Brushless Motor 661 Performance Characteristics 662 Cost Analysis 663 Comparison With Cylindrical Motor With Laminated Stator and Rotor Cores 67 Case Study: Low-Speed Coreless AFPM Brushless Generator 68 Characterist

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Axial Flux Permanent Magnet Brushless Machines

This paper describes a hybrid method for calculating the performance of a coreless stator axial flux permanent-magnet (AFPM) generator. The method uses a combination of finite-element analysis and theoretical analysis. The method is then incorporated into a multidimensional optimization procedure to optimally design a large power coreless stator AFPM generator. The measured performance of the manufactured prototype compares favorably with the predicted results. The design approach can be applied successfully to optimize the design of the coreless stator AFPM machine.

/pdf/optimal-design-of-a-coreless-stator-axial-flux-permanent-ghxt73qqvn.pdf

Optimal design of a coreless stator axial flux permanent-magnet generator

The finite element analysis method is used directly in optimisation algorithms to optimise in multidimensions the design of the cageless reluctance synchronous machine. Two optimisation methods are evaluated to minimise or maximise the function value. These are the direction set method of Powell and the quasi-Newton algorithm. Both methods proved to be successful, with some advantages and disadvantages. Using these methods at a power level below 10 kW, results are given of structures of the reluctance synchronous machine which have been optimised according to specific criteria. Calculated and measured results show that the maximum torque optimum designed reluctance synchronous machine has the advantages of high power density and high efficiency.

Direct finite element design optimisation of the cageless reluctance synchronous machine

In this paper, the performance of air-cored (ironless) stator axial flux permanent magnet machines with different types of concentrated-coil nonoverlapping windings is evaluated. The evaluation is based on theoretical analysis and is confirmed by finite-element analysis and measurements. It is shown that concentrated-coil winding machines can have a similar performance as that of normal overlapping winding machines using less copper.

Analysis and Performance of Axial Flux Permanent-Magnet Machine With Air-Cored Nonoverlapping Concentrated Stator Windings

This paper presents a hybrid method for the calculation of eddy current loss in coreless stator axial field permanent-magnet (AFPM) machines. The method combines the use of two-dimensional finite element (FE) field analysis and the closed-form eddy loss formula. To account for three-dimensional field effects in an AFPM machine, a multilayer and multislice modeling technique has been devised. Experimental tests are carried out to validate the method. It is shown that the proposed method predicts the eddy current losses of a coreless stator AFPM machine with high accuracy.

Maarten J. Kamper

Papers

Axial Flux Permanent Magnet Brushless Machines

Optimal design of a coreless stator axial flux permanent-magnet generator

Direct finite element design optimisation of the cageless reluctance synchronous machine

Analysis and Performance of Axial Flux Permanent-Magnet Machine With Air-Cored Nonoverlapping Concentrated Stator Windings

Calculation of eddy current loss in axial field permanent-magnet machine with coreless stator