Magnetic circuit

About: Magnetic circuit is a(n) research topic. Over the lifetime, 15707 publication(s) have been published within this topic receiving 118099 citation(s).

Two-reaction theory of synchronous machines generalized method of analysis-part I

Abstract: Starting with the basic assumption of no saturation or hysteresis, and with distribution of armature phase m. m. f. effectively sinusoidal as far as regards phenomena dependent upon rotor position, general formulas are developed for current, voltage, power, and torque under steady and transient load conditions. Special detailed formulas are also developed which permit the determination of current and torque on three-phase short circuit, during starting, and when only small deviations from an average operating angle are involved. In addition, new and more accurate equivalent circuits are developed for synchronous and asynchronous machines operating in parallel, and the domain of validity of such circuits is established. Throughout, the treatment has been generalized to include salient poles and an arbitrary number of rotor circuits. The analysis is thus adapted to machines equipped with field pole collars, or with amortisseur windings of any arbitrary construction. It is proposed to continue the analysis in a subsequent paper.

Brushless permanent-magnet motor design

Abstract: Written for electrical, electronics, and mechanical engineers responsible for designing and specifying motors, the book provides details of brushless DC and synchronous motors, as well as both radial and axial motor topologies. Beginning with a discussion of the fundamentals of generic motor design, it logically progresses to a set of more advanced, yet easily understandable, concepts for designing brushless permanent-magnet motors. In addition, the author fully explains techniques for magnetic modelling and circuit analysis, shows how magnetic circuit analysis applies to motor design, describes all major aspects of motor operation and design in simple mathematical terms, develops rigorous design equations for radial flux and axial flux motors, and illustrates basic motor drive schemes. All common motor design terms are clearly defined and a wealth of charts, tables and equations are included.

A novel high-performance magnetic gear

Abstract: Mechanical gearboxes are used extensively to match the operating speed of prime-movers to the requirements of their loads. Although, high system torque densities can be achieved, gear lubrication and cooling are often required, whilst noise, vibration and reliability can be significant issues. The paper describes the design and performance of a magnetic gear, which employs rare-earth magnets, which simulation studies have shown to have a transmitted torque density exceeding 100 kNm/m/sup 3/.

Adaptive input-output linearizing control of induction motors

Abstract: A nonlinear adaptive state feedback input-output linearizing control is designed for a fifth-order model of an induction motor which includes both electrical and mechanical dynamics under the assumptions of linear magnetic circuits. The control algorithm contains a nonlinear identification scheme which asymptotically tracks the true values of the load torque and rotor resistance which are assumed to be constant but unknown. Once those parameters are identified, the two control goals of regulating rotor speed and rotor flux amplitude are decoupled, so that power efficiency can be improved without affecting speed regulation. Full state measurements are required. >

Permanent Magnet and Electromechanical Devices: Materials, Analysis, and Applications

Abstract: Preface 1. Materials Introduction Units Classification of Materials Atomic Magnetic Moments Single electron atoms Multielectron atoms Paramagnetism Ferromagnetism Magnetostatic Energy Demagnetization Field Anisotropy Magnetocrystalline Anisotropy Shape Anisotropy Domains Hysteresis Soft Magnetic Materials Hard Magnetic Materials Ferrites Alnico Samarium-Cobalt Neodymium-iron-boron Bonded Magnets Magnetization Stability 2. Review of Maxwell's Equations Introduction Maxwell's Equations Constitutive Relations Integral Equations Boundary Conditions Force and Torque Potentials Quasi-static Theory Static Theory Magnetostatic Theory Electrostatic Theory Summary 3. Field Analysis Introduction Magnetostatic Analysis Vector Potential Force and Torque Maxwell Stress Tensor Energy Inductance The Current Model The Charge Model Force Torque Magnetic Circuit Analysis Current Sources Magnet Sources Boundary-Value Problems Cartesian Coordinates Cylindrical Coordinates Spherical Coordinates Method of Images Finite Element Analysis Finite Difference Method 4. Permanent Magnet Applications Introduction Magnet Structures Rectangular Structures Cylindrical Structures High Field Structures Magnetic Latching Magnetic Suspension Magnetic Gears Magnetic Couplings Magnetic Resonance Imaging Electrophotography Magneto-Optical Recording Free-Electron Lasers 5. Electromechanical Devices Introduction Device Basics Quasi-static Field Theory Stationary Reference Frame Moving Reference Frames Electrical Equations Stationary Circuits Moving Coils Mechanical Equations Electromechanical Equations Stationary Circuits Moving Coils Energy Analysis Magnetic Circuit Actuators Axial-Field Actuators Resonant Actuators Magneto-Optical Bias Field Actuator Linear Actuators Axial-Field Motors Stepper Motors Hybrid Analytical-FEM Analysis Magnetic MEMS Vector Analysis Cartesian Coordinates Cylindrical Coordinates Spherical Coordinates Integrals of Vector Functions Theorems and Identities Coordinate Transformations Green's Function Systems of Equations Euler's Method Improved Euler Method Runge-Kutta Methods Units