Transient Simulation of Magnetic Circuits Using the Permeance-Capacitance Analogy
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
Permanent Magnet Guidelines
MMPA PMG-88 PERMANENT MAGNET GUIDELINES I. Basic physics of permanent magnet materials II. Design relationships, figures of merit and optimizing techniques III. Measuring IV. Magnetizing V. Stabilizing and handling VI. Specifications, standards and communications VII. Bibliography MAGNETIC MATERIALS PRODUCERS ASSOCIATION 8 SOUTH MICHIGAN AVENUE • SUITE 1000 • CHICAGO, ILLINOIS 60603 INTRODUCTION This guide is a supplement to our MMPA Standard No. 0100. It relates the information in the Standard to permanent magnet circuit problems. The guide is a bridge between unit property data and a permanent magnet component having a specific size and geometry in order to establish a magnetic field in a given magnetic circuit environment. The MMPA 0100 defines magnetic, thermal, physical and mechanical properties. The properties given are descriptive in nature and not intended as a basis of acceptance or rejection. Magnetic measure- ments are difficult to make and less accurate than corresponding electrical mea- surements. A considerable amount of detailed information must be exchanged between producer and user if magnetic quantities are to be compared at two locations. MMPA member companies feel that this publication will be helpful in allowing both user and producer to arrive at a realistic and meaningful specifica- tion framework. Acknowledgment The Magnetic Materials Producers Association acknowledges the out- standing contribution of Rollin J. Parker to this industry and designers and manufacturers of products usingpermanent magnet materials. Mr Parker the Technical Consultant to MMPA compiled and wrote this document. We also wish to thank the Standards and Engineering Com- mittee of MMPA which reviewed and edited this document. December 1987 3M July 1988 5M August 1996 1M December 1998 1 M CONTENTS The guide is divided into the following sections: Glossary of terms and conversion tables- A very important starting point since the whole basis of communication in the magnetic material industry involves measurement of defined unit properties. -
Chapter 1 Magnetic Circuits and Magnetic Materials
Chapter 1 Magnetic Circuits and Magnetic Materials The objective of this course is to study the devices used in the interconversion of electric and mechanical energy, with emphasis placed on electromagnetic rotating machinery. The transformer, although not an electromechanical-energy-conversion device, is an important component of the overall energy-conversion process. Practically all transformers and electric machinery use ferro-magnetic material for shaping and directing the magnetic fields that acts as the medium for transferring and converting energy. Permanent-magnet materials are also widely used. The ability to analyze and describe systems containing magnetic materials is essential for designing and understanding electromechanical-energy-conversion devices. The techniques of magnetic-circuit analysis, which represent algebraic approximations to exact field-theory solutions, are widely used in the study of electromechanical-energy-conversion devices. §1.1 Introduction to Magnetic Circuits Assume the frequencies and sizes involved are such that the displacement-current term in Maxwell’s equations, which accounts for magnetic fields being produced in space by time-varying electric fields and is associated with electromagnetic radiations, can be neglected. Z H : magnetic field intensity, amperes/m, A/m, A-turn/m, A-t/m Z B : magnetic flux density, webers/m2, Wb/m2, tesla (T) Z 1 Wb =108 lines (maxwells); 1 T =104 gauss Z From (1.1), we see that the source of H is the current density J . The line integral of the tangential component of the magnetic field intensity H around a closed contour C is equal to the total current passing through any surface S linking that contour. -
Analysis of Magnetic Field and Electromagnetic Performance of a New Hybrid Excitation Synchronous Motor with Dual-V Type Magnets
energies Article Analysis of Magnetic Field and Electromagnetic Performance of a New Hybrid Excitation Synchronous Motor with dual-V type Magnets Wenjing Hu, Xueyi Zhang *, Hongbin Yin, Huihui Geng, Yufeng Zhang and Liwei Shi School of Transportation and Vehicle Engineering, Shandong University of Technology, Zibo 255049, China; [email protected] (W.H.); [email protected] (H.Y.); [email protected] (H.G.); [email protected] (Y.Z.); [email protected] (L.S.) * Correspondence: [email protected]; Tel.: +86-137-089-41973 Received: 15 February 2020; Accepted: 17 March 2020; Published: 22 March 2020 Abstract: Due to the increasing energy crisis and environmental pollution, the development of drive motors for new energy vehicles (NEVs) has become the focus of popular attention. To improve the sine of the air-gap flux density and flux regulation capacity of drive motors, a new hybrid excitation synchronous motor (HESM) has been proposed. The HESM adopts a salient pole rotor with built-in dual-V permanent magnets (PMs), non-arc pole shoes and excitation windings. The fundamental topology, operating principle and analytical model for a magnetic field are presented. In the analytical model, the rotor magnetomotive force (MMF) is derived based on the minimum reluctance principle, and the permeance function considering a non-uniform air-gap is calculated using the magnetic equivalent circuit (MEC) method. Besides, the electromagnetic performance including the air-gap magnetic field and flux regulation capacity is analyzed by the finite element method (FEM). The simulation results of the air-gap magnetic field are consistent with the analytical results. The experiment and simulation results of the performance show that the flux waveform is sinusoidal-shaped and the air-gap flux can be adjusted effectively by changing the excitation current. -
Design of Magnetic Circuits
Design of Magnetic Circuits Fundamental Equations Circuit laws similar to those of electric circuits apply in magnetic circuits as well. That is, a magnetic circuit can be replaced by an equivalent electric circuit for Ohm’s Law to be applied. If the magnetomotive force of a magnet is F and the total magnetic flux is Φt, and assuming the magnetic resistance (reluctance) of the circuit is R, then the following equation is valid. (1) Assuming the vacant length of the circuit as ℓg and the vacant cross-sectional area as ag, the magnetic resistance is then given by the following equation. (2) μ is the magnetic permeability of the magnetic path and is equivalent to the magnetic permeability μ0 of a vacuum in the case of air. (μ0=4π×10-7 [H/m]) Yoke 〈Figure 7〉 Although the current in an electric circuit rarely leaks outside the circuit, as the difference in the magnetic permeability between the conductor yoke and insulated area in a magnetic circuit is not very large, leakage of the magnetic flux also becomes large in reality. The amount of the magnetic flux leakage is expressed by the leakage factor σ, which is the ratio of the total magnetic flux Φt generated in the magnetic circuit to the effective magnetic flux Φg of the vacant space. (3) In addition, the loss in the magnetic flux due to the joints in the magnetic circuit must also be taken into consideration. This is represented by the reluctance factor f. Since the leakage factor σ is equivalent to the increase in the vacant space area, and the reluctance factor f refers to the correction coefficient of the vacant space length, the corrected magnetic resistance becomes as follows. -
University Physics 227N/232N Ch 27
Vector pointing OUT of page University Physics 227N/232N Ch 27: Inductors, towards Ch 28: AC Circuits Quiz and Homework This Week Dr. Todd Satogata (ODU/Jefferson Lab) [email protected] http://www.toddsatogata.net/2014-ODU Monday, March 31 2014 Happy Birthday to Jack Antonoff, Kate Micucci, Ewan McGregor, Christopher Walken, Carlo Rubbia (1984 Nobel), and Al Gore (2007 Nobel) (and Sin-Itiro Tomonaga and Rene Descartes and Johann Sebastian Bach too!) Prof. Satogata / Spring 2014 ODU University Physics 227N/232N 1 Testing for Rest of Semester § Past Exams § Full solutions promptly posted for review (done) § Quizzes § Similar to (but not exactly the same as) homework § Full solutions promptly posted for review § Future Exams (including comprehensive final) § I’ll provide copy of cheat sheet(s) at least one week in advance § Still no computer/cell phone/interwebz/Chegg/call-a-friend § Will only be homework/quiz/exam problems you have seen! • So no separate practice exam (you’ll have seen them all anyway) § Extra incentive to do/review/work through/understand homework § Reduces (some) of the panic of the (omg) comprehensive exam • But still tests your comprehensive knowledge of what we’ve done Prof. Satogata / Spring 2014 ODU University Physics 227N/232N 2 Review: Magnetism § Magnetism exerts a force on moving electric charges F~ = q~v B~ magnitude F = qvB sin ✓ § Direction follows⇥ right hand rule, perpendicular to both ~v and B~ § Be careful about the sign of the charge q § Magnetic fields also originate from moving electric charges § Electric currents create magnetic fields! § There are no individual magnetic “charges” § Magnetic field lines are always closed loops § Biot-Savart law: how a current creates a magnetic field: µ0 IdL~ rˆ 7 dB~ = ⇥ µ0 4⇡ 10− T m/A 4⇡ r2 ⌘ ⇥ − § Magnetic field field from an infinitely long line of current I § Field lines are right-hand circles around the line of current § Each field line has a constant magnetic field of µ I B = 0 2⇡r Prof. -
Power-Invariant Magnetic System Modeling
POWER-INVARIANT MAGNETIC SYSTEM MODELING A Dissertation by GUADALUPE GISELLE GONZALEZ DOMINGUEZ Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY August 2011 Major Subject: Electrical Engineering Power-Invariant Magnetic System Modeling Copyright 2011 Guadalupe Giselle González Domínguez POWER-INVARIANT MAGNETIC SYSTEM MODELING A Dissertation by GUADALUPE GISELLE GONZALEZ DOMINGUEZ Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Approved by: Chair of Committee, Mehrdad Ehsani Committee Members, Karen Butler-Purry Shankar Bhattacharyya Reza Langari Head of Department, Costas Georghiades August 2011 Major Subject: Electrical Engineering iii ABSTRACT Power-Invariant Magnetic System Modeling. (August 2011) Guadalupe Giselle González Domínguez, B.S., Universidad Tecnológica de Panamá Chair of Advisory Committee: Dr. Mehrdad Ehsani In all energy systems, the parameters necessary to calculate power are the same in functionality: an effort or force needed to create a movement in an object and a flow or rate at which the object moves. Therefore, the power equation can generalized as a function of these two parameters: effort and flow, P = effort × flow. Analyzing various power transfer media this is true for at least three regimes: electrical, mechanical and hydraulic but not for magnetic. This implies that the conventional magnetic system model (the reluctance model) requires modifications in order to be consistent with other energy system models. Even further, performing a comprehensive comparison among the systems, each system’s model includes an effort quantity, a flow quantity and three passive elements used to establish the amount of energy that is stored or dissipated as heat. -
Magnetism and Magnetic Circuits
UNIVERSITY OF BABYLON BASIC OF ELECTRICAL ENGINEERING LECTURE NOTES Magnetism and Magnetic Circuits The Nature of a Magnetic Field: Magnetism refers to the force that acts between magnets and magnetic materials. We know, for example, that magnets attract pieces of iron, deflect compass needles, attract or repel other magnets, and so on. The region where the force is felt is called the “field of the magnet” or simply, its magnetic field. Thus, a magnetic field is a force field. Using Faraday’s representation, magnetic fields are shown as lines in space. These lines, called flux lines or lines of force, show the direction and intensity of the field at all points. The field is strongest at the poles of the magnet (where flux lines are most dense), its direction is from north (N) to south (S) external to the magnet, and flux lines never cross. The symbol for magnetic flux as shown is the Greek letter (phi). What happens when two magnets are brought close together? If unlike poles attract, and flux lines pass from one magnet to the other. الصفحة 321 Saad Alwash UNIVERSITY OF BABYLON BASIC OF ELECTRICAL ENGINEERING LECTURE NOTES If like poles repel, and the flux lines are pushed back as indicated by the flattening of the field between the two magnets. Ferromagnetic Materials (magnetic materials that are attracted by magnets such as iron, nickel, cobalt, and their alloys) are called ferromagnetic materials. Ferromagnetic materials provide an easy path for magnetic flux. The flux lines take the longer (but easier) path through the soft iron, rather than the shorter path that they would normally take. -
MAGNETISM and Its Practical Applications
Mechanical Engineering Laboratory A short introduction to… MAGNETISM and its practical applications Michele Togno – Technical University of Munich, 28 th March 2014 – 4th April 2014 Mechanical Engineering laboratory - Magnetism - 1 - Magnetism A property of matter A magnet is a material or object that produces a magnetic field. This magnetic field is invisible but it is responsible for the most notable property of a magnet: a force that pulls on ferromagnetic materials, such as iron, and attracts or repels other magnets. History of magnetism Magnetite Fe 3O4 Sushruta, VI cen. BCE (lodestone) (Indian surgeon) J.B. Biot, 1774-1862 A.M. Ampere, 1775-1836 Archimedes (287-212 BCE) William Gilbert, 1544-1603 H.C. Oersted, 1777-1851 (English physician) C.F. Gauss, 1777-1855 F. Savart, 1791-1841 M. Faraday, 1791-1867 J.C. Maxwell, 1831-1879 Shen Kuo, 1031-1095 (Chinese scientist) H. Lorentz, 1853-1928 Mechanical Engineering laboratory - Magnetism - 2 - The Earth magnetic field A sort of cosmic shield Mechanical Engineering laboratory - Magnetism - 3 - Magnetic domains and types of magnetic materials Ferromagnetic : a material that could exhibit spontaneous magnetization, that is a net magnetic moment in the absence of an external magnetic field (iron, nickel, cobalt…). Paramagnetic : material slightly attracted by a magnetic field and which doesn’t retain the magnetic properties when the external field is removed (magnesium, molybdenum, lithium…). Diamagnetic : a material that creates a magnetic field in opposition to an externally applied magnetic field (superconductors…). Mechanical Engineering laboratory - Magnetism - 4 - Magnetic field and Magnetic flux Every magnet is a magnetic dipole (magnetic monopole is an hypothetic particle whose existence is not experimentally proven right now). -
6.685 Electric Machines, Course Notes 2: Magnetic Circuit Basics
Massachusetts Institute of Technology Department of Electrical Engineering and Computer Science 6.685 Electric Machines Class Notes 2 Magnetic Circuit Basics c 2003 James L. Kirtley Jr. 1 Introduction Magnetic Circuits offer, as do electric circuits, a way of simplifying the analysis of magnetic field systems which can be represented as having a collection of discrete elements. In electric circuits the elements are sources, resistors and so forth which are represented as having discrete currents and voltages. These elements are connected together with ‘wires’ and their behavior is described by network constraints (Kirkhoff’s voltage and current laws) and by constitutive relationships such as Ohm’s Law. In magnetic circuits the lumped parameters are called ‘Reluctances’ (the inverse of ‘Reluctance’ is called ‘Permeance’). The analog to a ‘wire’ is referred to as a high permeance magnetic circuit element. Of course high permeability is the analog of high conductivity. By organizing magnetic field systems into lumped parameter elements and using network con- straints and constitutive relationships we can simplify the analysis of such systems. 2 Electric Circuits First, let us review how Electric Circuits are defined. We start with two conservation laws: conser- vation of charge and Faraday’s Law. From these we can, with appropriate simplifying assumptions, derive the two fundamental circiut constraints embodied in Kirkhoff’s laws. 2.1 KCL Conservation of charge could be written in integral form as: dρ J~ · ~nda + f dv = 0 (1) ZZ Zvolume dt This simply states that the sum of current out of some volume of space and rate of change of free charge in that space must be zero. -
Reluctance Network Analysis for Complex Coupled Inductors
Journal of Power and Energy Engineering, 2017, 5, 1-14 http://www.scirp.org/journal/jpee ISSN Online: 2327-5901 ISSN Print: 2327-588X Reluctance Network Analysis for Complex Coupled Inductors Jyrki Penttonen1,2*, Muhammad Shafiq2, Matti Lehtonen1 1Department of Electrical Engineering, Aalto University, Espoo, Finland 2Vensum Ltd., Helsinki, Finland How to cite this paper: Penttonen, J., Abstract Shafiq, M. and Lehtonen, M. (2017) Reluc- tance Network Analysis for Complex The use of reluctance networks has been a conventional practice to analyze Coupled Inductors. Journal of Power and transformer structures. Basic transformer structures can be well analyzed Energy Engineering, 5, 1-14. by using the magnetic-electric analogues discovered by Heaviside in the 19th http://dx.doi.org/10.4236/jpee.2017.51001 century. However, as power transformer structures are getting more complex Received: December 16, 2016 today, it has been recognized that changing transformer structures cannot be Accepted: January 7, 2017 accurately analyzed using the current reluctance network methods. This paper Published: January 10, 2017 presents a novel method in which the magnetic reluctance network or arbi- Copyright © 2017 by authors and trary complexity and the surrounding electrical networks can be analyzed as a Scientific Research Publishing Inc. single network. The method presented provides a straightforward mapping This work is licensed under the Creative table for systematically linking the electric lumped elements to magnetic cir- Commons Attribution International License (CC BY 4.0). cuit elements. The methodology is validated by analyzing several practical http://creativecommons.org/licenses/by/4.0/ transformer structures. The proposed method allows the analysis of coupled Open Access inductor of any complexity, linear or non-linear. -
Magnetic Theory and Applications.Cdr
Magnetic Theory & Applications All materials are defined as being magnetic in that they respond to the application of an applied magnetic field differently to that of air or vacuum. Only selected elements or alloys have useful magnetic properties in engineering applications. B Magnetic materials which are easily magnetized and the magnetized are often termed soft. Conversely, those magnetic materials where any induced magnetism Normal is difficult to remove are termed hard or permanent. Intrinsic When a practical or highly permeable material is influenced by an external Initial magnetisation curve magnetic field it may acquire a large magnetization or magnetic induction. The level J of the magnetization will be related to the individual intrinsic permeability of the B HcJ HcB material in question. The relationship between the external field in the induction is: H B = µH where B is the magnetic induction and where µ is the permeability and where H is the external magnetic field. Br Remanence HcB Normal coercivity HcJ Intrinsic coercivity In the S. I. system of units, B is defined in terms of the tesla (T) and the magnetic field H in ampere per meter (A/m). When the external field, H and induction, B are identical (i.e. in a vacuum) the permeability µ is exactly 4π x 10-7 in units of henry per meter for the equation to balance. It is termed µo. Hence: B B = µo H Initial magnetisation curve Bmax In strongly magnetic materials the relationship is: B r A ΔB H B = µ µ H where µ is the relative c o r r H ΔH permeability of the Hysteresis loop material. -
Magnetic Circuits Magnetic Circuit Definitions
ELG2336: Magnetic Circuits Magnetic Circuit Definitions • Magnetomotive Force – The “driving force” that causes a magnetic field – Symbol, F – Definition, F = NI – Units, Ampere-turns, (A-t) 2 Magnetic Circuit Definitions • Magnetic Field Intensity – mmf gradient, or mmf per unit length – Symbol, H – Definition, H = F/l = NI/l – Units, (A-t/m) 3 Magnetic Circuit Definitions • Flux Density – he concentration of the lines of force in a magnetic circuit – Symbol, B – Definition, B = Φ/A – Units, (Wb/m2), or T (Tesla) 4 Magnetic Circuit Definitions • Reluctance – The measure of “opposition” the magnetic circuit offers to the flux – The analog of Resistance in an electrical circuit – Symbol, R – Definition, R = F/Φ – Units, (A-t/Wb) 5 Magnetic Circuit Definitions • Permeability – Relates flux density and field intensity – Symbol, μ – Definition, μ = B/H – Units, (Wb/A-t-m) ECE 441 6 Magnetic Circuit Definitions • Permeability of free space (air) – Symbol, μ0 -7 – μ0 = 4πx10 Wb/A-t-m 7 Definitions Combined (Unit is Weber (Wb)) = Magnetic Flux Crossing a Surface of Area ‘A’ in m2. B (Unit is Tesla (T)) = Magnetic Flux Density = /A B H (Unit is Amp/m) = Magnetic Field Intensity = = permeability = o r -7 o = 4*10 H/m (H Henry) = Permeability of free space (air) r = Relative Permeability r >> 1 for Magnetic Material 8 Magnetic Circuit 9 Air Gaps, Fringing, and Laminated Cores • Circuits with air gaps may cause fringing • Correction – Increase each cross-sectional dimension of gap by the size of the gap • Many applications use laminated cores