Mitchell Wing

Bio: Mitchell Wing is an academic researcher from University of Cape Town. The author has contributed to research in topics: Finite element method & Direct torque control. The author has an hindex of 1, co-authored 3 publications receiving 640 citations.

Permanent magnet motor technology : design and applications

Abstract: Preface 1. Introduction 1.1 Permanent magnet versus electromagnetic excitation 1.2 Permanent magnet motor drives 1.3 Towards increasing the motor efficiency 1.4 Classification of permanent magnet electric motors 1.5 Trends in permanent magnet motors and drives industry 1.6 Applications of permanent magnet motors 1.7 Mechatronics 1.8 Fundamentals of mechanics of machines 1.9 Torque balance equation 1.10 Evaluation of cost of a PM motor 2. Permanent Magnet Materials and Circuits 2.1 Demagnetization curve and magnetic parameters 2.2 Early history of permanent magnets 2.3 Properties of permanent magnets 2.4 Approximation of demagnetization curve and recoil line 2.5 Operating diagram 2.6 Permeances for main and leakage fluxes 2.7 Calculation of magnetic circuits with permanent magnets 2.8 Mallinson-Halbach array and Halbach cylinder 3. Finite Element Analysis 3.1. Gradient, divergence and curl 3.2 Biot-Savart, Faraday's, and Gauss's laws 3.3 Gauss's theorem 3.4 Stokes' theorem 3.5 Maxwell's equations 3.6 Magnetic vector potential 3.7 Energy functionals 3.8 Finite element formulation 3.9 Boundary conditions 3.10 Mesh generation 3.11 Forces and torques in electromagnetic field 3.12 Inductances 3.13 Interactive FEM programs 4. Permanent Magnet d.c. Commutator Motors 4.1 Construction 4.2 Fundamental equations 4.3 Sizing procedure 4.4 Armature reaction 4.5 Commutation 4.6 Starting 4.7 Speed control 4.8 Servo motors 4.9 Magnetic circuit 4.10 Applications 5. Permanent Magnet Synchronous Motors 5.1 Construction 5.2 Fundamental relationships 5.3 Phasor diagram 5.4 Characteristics 5.5 Starting 5.6 Reactances 5.7 Rotor configurations 5.8 Comparison between synchronous and induction motors 5.9 Sizing procedure and main dimensions 5.10 Performance calculation 5.11 Dynamic model of a PM motor 5.12 Noise and vibration of electromagnetic origin 5.13 Applications 6. d.c. Brushless Motors 6.1 Fundamental equations 6.2 Commutation of PM brushless motors 6.3 EMF and torque of PM brushless motors 6.4 Torque-speed characteristics 6.5 Winding losses 6.6 Torque ripple 6.7 Rotor position sensing of d.c. brushless motors 6.8 Sensorless motors 6.9 Motion Control of PM brushless motors 6.10 Universal brushless motor electromechanical drives 6.11 Smart motors 6.12 Applications 7. Axial Flux Motors 7.1 Force and torque 7.2 Performance 7.3 Double-sided motor with internal PM disk rotor 7.4 Double-sided motor with one stator 7.5 Single-sided motors 7.6 Ironless double-sided motors 7.7 Multidisk motors 7.8 Applications 8. High Power Density Brushless Motors 8.1 Design considerations 8.2 Requirements 8.3 Multiphase motors 8.4 Fault-tolerant PM brushless machines 8.5 Surface PM versus salient-pole rotor 8.6 Electromagnetic effects 8.7 Cooling 8.8 Construction of motors with cylindrical rotors 8.9 Construction of motors with disk rotors 8.10 Transverse flux motors 8.11 Applications 9. High Speed Motors 9.1 Why high speed motors? 9.2 Mechanical requirements 9.3 Construction of high speed PM brushless motors 9.4 Design of high speed PM brushless motors 9.5 Ultra high speed motors 9.6 Applications 10. Brushless Motors of Special Construction 10.1 Single-phase motors 10.2 Actuators for automotive 10.3 Integrated starter-generator 10.4 Large diameter motors 10.5 Three-axis torque motor 10.6 Slotless motors 10.7 Tip driven fan motors 11. Stepping Motors 11.1 Features of stepping motors 11.2 Fundamental equations 11.3 PM stepping motors 11.4 Reluctance stepping motors 11.5 Hybrid stepping motors 11.6 Motion control of stepping motors 11.7 PM stepping motors with rotor position transducers 11.8 Single-phase stepping motors 11.9 Voltage Equations and Electromagnetic Torque 11.10 Characteristics 11.11 Applications 12. Micromotors 12.1 What is a micromotor? 12.2 Permanent magnet brushless micromotors 12.3 Applications 13. Optimization 13.1 Mathematical formulation of optimization problem 13.2 Nonlinear programming methods 13.3 Population-based incremental learning 13.4 Response surface methodology 13.5 Modern approach to optimization of PM motors 14. Maintenance 14.1 Basic requirements to electric motors 14.2 Reliability 14.3 Failures of electric motors 14.4 Calculation of reliability of small PM brushless motors 14.5 Vibration and noise 14.6 Condition monitoring 14.7 Protection 14.8 Electromagnetic and radio frequency interference 14.9 Lubrication Appendices A. Leakage Inductance of a.c. Stator Windings B. Losses in a.c. Motors Symbols and Abbreviations References Index

Accuracy of finite elements in computing the synchronous reactances of surface and buried permanent magnet brushless motors

Abstract: The increased use of permanent magnet synchronous motors in small to medium power applications has made it imperative that these motors' performance can be modelled successfully. The accuracy of calculating the synchronous reactances determines the success of the modelling technique. An analytical method and the finite element method are used to calculate the synchronous reactances of two prototype synchronous motors. The calculations are compared with measurement for both motors. The results show that the finite element method is more reliable in obtaining synchronous reactances than the analytical method for rotor designs that are very intricate, although both methods show reasonable accuracy.

Transient simulation of permanent magnet dc commutator motors using the finite element approach

Abstract: The transient performance of permanent magnet dc commutator motors has been simulated using a two dimensional finite element model. The simulations of start‐up characteristics and braking conditions are concentrated on. The finite element approach in simulating transients of dc motors is discussed with a proposed solution to the problem A finite element solution that ignores the induced eddy current losses in the small volume rotor is shown as a quick solution that gives fair accuracy. The results are compared against experimental data obtained for a 370 W permanent magnet dc motor using a data acquisition system.

Magnetic materials and devices for the 21st century: Stronger, lighter, and more energy efficient

Abstract: A new energy paradigm, consisting of greater reliance on renewable energy sources and increased concern for energy effi ciency in the total energy lifecycle, has accelerated research into energy-related technologies. Due to their ubiquity, magnetic materials play an important role in improving the effi ciency and performance of devices in electric power generation, conditioning, conversion, transportation, and other energy-use sectors of the economy. This review focuses on the state-of-the-art hard and soft magnets and magnetocaloric materials, with an emphasis on their optimization for energy applications. Specifi cally, the impact of hard magnets on electric motor and transportation technologies, of soft magnetic materials on electricity generation and conversion technologies, and of magnetocaloric materials for refrigeration technologies, are discussed. The synthesis, characterization, and property evaluation of the materials, with an emphasis on structure‐property relationships, are discussed in the context of their respective markets, as well as their potential impact on energy effi ciency. Finally, considering future bottlenecks in raw materials, options for the recycling of rare-earth intermetallics for hard magnets will be discussed.

Review of design considerations and technological challenges for successful development and deployment of plug-in hybrid electric vehicles

Abstract: Automobile drivetrain hybridization is considered as an important step in reducing greenhouse gases and related automotive emissions. However, current hybrid electric vehicles are a temporary solution on the way to zero emission road vehicles. Recently there has been a lot of interest in the concept of plug-in hybrid electric vehicles, which have great potential to attain higher fuel economy and efficiency, with a longer range in pure electric propulsion mode. PHEVs represent the next generation of hybrid vehicles that bridges the gap between present hybrid electric vehicles and battery operated electric vehicles. In this paper a brief review of design considerations and selection of major components for plug-in hybrid electric vehicles is provided. This paper also focuses on the technological challenges ahead of plug-in hybrid electric vehicles in relation to its major components, which are reviewed in detail. The importance of economics and government support for the successful deployment of this plug-in hybrid technology in the near future to achieve national energy security is also discussed in the paper.

Linear Synchronous Motors : Transportation and Automation Systems

Abstract: Topology and Selection Definitions, Geometry, and Thrust Generation Linear Synchronous Motor Topologies Calculation of Forces Linear Motion Selection of Linear Motors Materials and Construction Materials Laminated Ferromagnetic Cores Permanent Magnets Conductors Principles of Superconductivity Laminated Stacks Armature Windings of Slotted Cores Slotless Armature Systems Electromagnetic Excitation Systems Superconducting Excitation Systems Hybrid Linear Stepping Motors Theory of Linear Synchronous Motors Permanent Magnet Synchronous Motors Motors with Superconducting Excitation Coils Variable Reluctance Motors Permanent Magnet Hybrid Motors Motion Control Control of AC Motors EMF and Thrust of PM Synchronous and Brushless Motors Dynamic Model of a PM Motor Thrust and Speed Control of PM Motors Control of Hybrid Stepping Motors Precision Linear Positioning Sensors Linear Optical Sensors Linear magnetic Encoders High Speed Maglev Transport Electromagnetic and Electrodynamic Levitation Transrapid System (Germany) Yamanashi Maglev Test Line in Japan Swissmetro Marine Express Building and Factory Transportation Systems Elevator Hoisting Machines Ropeless Elevators Assessment of Hoist Performance Horizontal Transportation systems Industrial Automation Systems Automation of Manufacturing Processes Casting Processes Machining Processes Welding and Thermal Cutting Surface Treatment and Finishing Material Handling Testing Industrial Laser Applications Appendix A Magnetic Circuits with Permanent Magnets Appendix B Permeances for Magnetic Fluxes Appendix C Performance Calculations for PM LSMs Symbols and Abbreviations References

Modeling of axial flux permanent-magnet machines

Abstract: In modeling axial field machines, three-dimensional (3-D) finite-element method (FEM) models are required in accurate computations. However, 3-D FEM analysis is generally too time consuming in industrial use. In order to evaluate the performance of the axial flux machine rapidly, an analytical design program that uses quasi-3-D computation is developed. In this paper the main features of the developed program are illustrated. Results given by the program are verified with two-dimensional and 3-D finite element computations and measurements. According to the results, it is possible to evaluate the performance of the surface-mounted axial flux PM machine with reasonable accuracy via an analytical model using quasi-3-D computation.

Fault Detection by Means of Hilbert–Huang Transform of the Stator Current in a PMSM With Demagnetization

Abstract: This paper presents a novel method to diagnose demagnetization in permanent-magnet synchronous motor (PMSM). Simulations have been performed by 2-D finite-element analysis in order to determine the current spectrum and the magnetic flux distribution due to this failure. The diagnostic just based on motor current signature analysis can be confused by eccentricity failure because the harmonic content is the same. Moreover, it can only be applied under stationary conditions. In order to overcome these drawbacks, a novel method is used based upon the Hilbert-Huang transform. It represents time-dependent series in a 2-D time-frequency domain by extracting instantaneous frequency components through an empirical-mode decomposition process. This tool is applied by running the motor under nonstationary conditions of velocity. The experimental results show the reliability and feasibility of the methodology in order to diagnose the demagnetization of a PMSM.