电机学英文版课件01.ppt

1、Electric Machinery and Drive Fall Semester 2009Dept. of Electrical EngineeringPowerPoint Slidesto accompanyElectric MachineryFourth EditionStephen J. ChapmanChapter 1Introduction to Machinery PrinciplesObjectives To instill an understanding of the underlying electromagnetic effects permitting electr

2、ic machine operation and introduce basic machine types To describe the construction of these machines To examine the main types of these machines To be skilled in analyzing the characteristic of these machinesIntroduction and OverviewReference Books 1.Theodore Wildi. Electrical Machines, Drives, and

3、 Power Systems (Fifth Edition) Pearson Education. 2002 2. A. E. Fitzgerald, Charles Kingsley, Jr., Stephen D. Umans Electric Machinery (Sixth Edition) McGraw-Hill.2003 3. 李发海 王岩. 电机与拖动基础 北京：清华大学出版社，1994. 4. 顾绳谷. 电机及拖动基础(上、下册) 北京：机械工业出版社，1980 5. 汤蕴缪 史乃. 电机学 第二版 北京：机械工业出版社，2005.1 6. 姚舜才付 巍 赵耀霞 电机学与电力拖

4、动技术 北京：国防工业出版社，2006.1What is an Electric-Machine Drive?Type of Electrical MachinesEMMotorGeneratorDC MotorAC MotorSeparately ExcitedNon-Separately ExcitedSeriesShuntCompoundSynchronousAsynchronousSingle PhaseDouble PhaseThree PhaseDC GeneratorAC Generator Angular Position Angular Velocity Angular Ac

5、celerationdtddtdrv260mmmmffndtddtdva Torque T T=(Force Applied) (Perpendicular Distance) =(F)(r sin ) Newtons Law of Rotation T=J Work W Power PTdWFdrWTdtdrTTrdtddtdWPFvdtdrFFrdtddtdWPdtdWP)()(TWFrWElectric Drives An electric drive is a system that converts electrical energy to mechanical energy Par

6、ts: electric motor (or several) control system (including software) Constant-speed drives only a start/stop and protection system in addition to the electric motor Variable-speed drives (VSDs) include an electronic power converterElectric Drive and the Surrounding SystemAcceleration of Inertial Mass

7、 Torque needed for accelerating the moment of inertia J: Moment of inertia ofa thin-walled cylinder Moment of inertia of a solid cylinderEquation of MotiondtdJTTmL Inertia J is a theoretical parameter. In engineering, Fly Wheel GD2 is used to replace inertia. That is： dtdnGDTTL3752Copyright The McGr

8、aw-Hill Companies, Inc. Permission required for reproduction or display.Simple magnetic circuit.Figure 1.11-15Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display.Magnetic circuit with air gap.Figure 1-31-16 Production of a Magnetic Field Amperes Law H =magnetic

9、field intensity (Ampere-turns per meter) B=magnetic flux density/ intensity of magnetic induction =magnetic permeabilitynetIdlHcclNiHNiHlHBclNiHB Magnetic flux Magnetomotive Magnetic reluctanceAdABclNiABABAmRFAlRcmAnalogy between electric and magnetic circuits. (a) Electric circuit, (b) magnetic cir

10、cuit.Figure 1-4 Kirchhoffs Law in Magnetic Circuit0321 0FINIlHknk1lINmmRRHHlF210Air-gap fringing fields.Figure 1-6Simple synchronous machine.Figure 1-9(a) Magnetic circuit and (b) equivalent circuit for Example 1.3.Figure 1.6MATLAB plot of inductance vs. relative permeability for Example 1.5.Figure

11、1.7Magnetic circuit with two windings.Figure 1.8B-H loops for M-5 grain-oriented electrical steel 0.012 in thick. Only the top halves of the loops are shown here. (Armco Inc.)Figure 1-10Dc magnetization curve for M-5 grain-oriented electrical steel 0.012 in thick. (Armco Inc.)Figure 1.10Excitation p

12、henomena. (a) Voltage, flux, and exciting current; (b) corresponding hysteresis loop.Figure 1.11Exciting rms voltamperes per kilogram at 60 Hz for M-5 grain-oriented electrical steel 0.012 in thick. (Armco Inc.)Figure 1-10Hysteresis loop; hysteresis loss is proportional to the loop area (shaded).Fig

13、ure 1-11Core loss at 60 Hz in watts per kilogram for M-5 grain-oriented electrical steel 0.012 in thick. (Armco Inc.)Figure 1.14Laminated steel core with winding for Example 1.8.Figure 1.15(a) Second quadrant of hysteresis loop for Alnico 5;(b) second quadrant of hysteresis loop for M-5 electrical s

14、teel; (c) hysteresis loop for M-5 electrical steel expanded for small B. (Armco Inc.)Figure 1.16Magnetic circuit for Example 1.9.Figure 1.17Magnetic circuit for Example 1.10.Figure 1.18Magnetization curves for common permanent-magnet materials.Figure 1.19Magnetic circuit including both a permanent m

15、agnet and an excitation winding.Figure 1.20Portion of a B-H characteristic showing a minor loop and a recoil line.Figure 1.21Magnetic circuit for Example 1.11.Figure 1.22(a) Magnetization curve for Alnico 5 for Example 1.11; (b) series of load lines for Ag = 2 cm2 and varying of values of i showing

16、the magnetization procedure for Example 1.11. Figure 1.23(a)(b)Magnetic circuit for Problem 1.1.Figure 1.24Magnetic circuit for Problem 1.6.Figure 1.25Magnetic circuit for Problem 1.9.Figure 1.26Inductor for Problem 1.12.Figure 1.27Pot-core inductor for Problem 1.15.Figure 1.28Inductor for Problem 1

17、.17.Figure 1.29Toroidal winding for Problem 1.19.Figure 1.30Iron-core inductor for Problem 1.20.Figure 1.31Magnetic circuit for Problem 1.22.Figure 1.32Symmetric magnetic circuit for Problem 1.23.Figure 1.33Reciprocating generator for Problem 1.24.Figure 1.34Configuration for measurement of magnetic

18、 properties of electrical steel.Figure 1.35Magnetic circuit for Problem 1.28.Figure 1.36Magnetic circuit for the loudspeaker of Problem 1.34 (voice coil not shown).Figure 1.37Magnetic circuit for Problem 1.35. Figure 1.38 Production of Induced Force On a Wirei=magnitude of current in the wireB=magne

19、tic flux density vectorl= length of conductor in the magnetic field)(BliFsinilBF ilBF Induced Voltage On a Conductor Moving In a Magnetic Fieldv=velocity of the wireB=magnetic flux density vectorl= length of conductor in the magnetic fieldlBvE)(BlvE Three Phase PowerThree Phase PowerThe instantaneou

20、s total power is constant!Three Phase PowerThree Phase Power Real Power per phase isP = Vp Ip cos() Real Power for all three phases isP = 3 Vp Ip cos() Since for a balanced load the power is constantP(t) = 3 Vp Ip cos() also Power in Terms of Line QuantitiesP = 3 Vll Ill cos()Three Phase Reactive Po

21、wer QThree Phase Reactive Power Q Total supply Volt Amps product (VA) isVA = 3 Vll Ill Reactive power Q is the Quantity making up the difference between VA and PowerQ = 3 Vll Ill sin() Thus VA2 = P2 + Q2 Q is a measure of the energy storage capability of the circuit For the greatest Power per amp of supply the Power Factor should be Unity and Q should be zero