基于MATLABSimulink的異步電機(jī)仿真

1、Induction Motor Tests Using MATLAB/Simulink and Their Integration Into Undergraduate Electric Machinery CoursesAbstractThis paper describes MATLAB/Simulink implementation of three induction motor tests, namely dc, no-load,nd blocked-rotor tests performed to identify equivalent circuitparameters. The

2、se simulation models are developed to supportnd enhance electric machinery education at the undergraduate evel. The proposed tests have been successfully integrated intolectric machinery courses at Drexel University, Philadelphia, PA,and Nigde University, Nigde. Turkey.Index TermsEducation, inductio

3、n motors, MATLAB/Simulink, software laboratory.I. INTRODUCTIONWITH THE advent of low-cost personal computers and various easily accessible software packages, computer-aided teaching tools have become an essential part of both classroom lectures and laboratory experiments in electrical machinery educ

4、ation 16. The computer models and simulations of induction motors, as teaching tools, support the classroom teaching by enabling the instructor, through the computer-generated graphics, to illustrate easily steady-state operation of themotor under various loading conditions . The computational tools

5、 as a part of laboratory experimentsenhance laboratory experience by providing students with the opportunity to verify the results of laboratory experiments and compare them with those obtained by computer simulations.Such a comparison opportunity helps students realize the limitations of hardware e

6、xperiments and, as a counterpoint, appreciate that computer models cannot substitute for actual hardware experiments that might not exactly represent the operation of induction motors because of some modeling assumptions.Moreover, an undergraduate electric machinery course that integrates up-to-date

7、 computer hardware and software tools in both lecture and laboratory sections also meets the expectationsof todays students who want to use computers and simulation tools in every aspects of a course, and thus, possibly attracts more students. Electrical machinery courses at the undergraduate level

8、typically consist of classroom and laboratory sections. The classroom section covers the steady-state operation of the induction motor in which the per-phase equivalent circuit is used to compute various motor quantities, such as input current and power, power factor, developed torque, and efflcienc

9、y. The computations associated with the steady-state operation require the knowledge of equivalent circuit parameters. These parameters are obtained by performing three tests, namely dc, no-load, andblocked-rotor tests on the motor in a typical laboratory experiment. The laboratory section includes

10、these tests and a load experment that allows students to become familiar with the inducion motor operation and to gain invaluable hardware and measurement experiences. The authors experience while teaching nduction motors at Drexel University, Philadelphia, PA, indicates that students generally have

11、 difflculty when they come to he laboratory to carry out these experiments even though the corresponding theory is extensively covered in the classroomsection with a detailed hand-out describing laboratory facilitiesand the procedure of the experiments, given to them at least a week before the labor

12、atory. Students are not familiar with a laboratory environment that contains large machines and relatively complex measurement methods and devices as compared with other laboratories they have been to before. The time constraints during the laboratory exercise are also a difflcult adjustment. In a u

13、sual two-hour laboratory section, students are required to set up and perform four induction motor experiments, to take the necessary measurements, and to investigate steady-state performance of the motor under various loading conditions. Because of the time limitations, students often rush through

14、the experiments in order to flnish them on time, which unfortunately prevents them from getting a true feeling of motor operation and rom appreciating what has been accomplished during the laboratory practice.Therefore, simulation tools must be developed for induction motor experiments to serve as u

15、seful preparatory exercises before students come to the laboratory. The objective of this paper is to present simulation models of these induction motor experiments in an effort to design a computational laboratory.The dc, no-load, and blocked-rotor simulation models are developed as stand-alone app

16、lications using MATLAB/Simulink and Power System Blockset (PSB) . For the load experiment, students are required to write a computer program using MATLABs M-flle programming for the per-phase equivalent circuit of the induction motor to compute operating quantities.Such an assignment improves studen

17、ts programming skills that would be helpful in other classes as well. The remainder of the paper is organized as follows. Section II describes the dc, no-load, and blocked-rotor tests. For the sake of completeness, first the experimental setup for each test is provided with a brief explanation of ho

18、w these tests are conducted and how the corresponding measurements are used to compute the equivalent circuit parameters. Then, for each test, the corresponding Simulink/PSB model is presented and compared with the actual experimental setup emphasizing the similarities and discrepancies. Section III

19、 compares the equivalent circuit parameters determined using simulation data and data obtained from experiments. Section IV explains how to integrate these simulation models into undergraduate electric machine courses at two different universities, while the last section concludes the paper. II. IND

20、UCTION MOTOR TESTS:EXPERIMENTAL SETUPS AND SIMULINK/PSB MODELSThe steady-state operating characteristics of a three-phase induction motor are often investigated using a perphase equivalent circuit as shown in Flg. In this circuit,R1 and X1 represent stator resistance and leakage reactance, respectiv

21、ely;R2 and X2 denote the rotor resistance and leakage reactance referred to the stator, respectively;RC resistance stands for core losses;XM represents magnetizing reactance; and S denotes the slip. The equivalent circuit is used to facilitate the computation of various operating quantities, such as

22、 stator current, input power, losses, induced torque, and efciency. When power as pects of the operation need to be emphasized, the shunt resistance(Rc)is usually neglected; the core losses can be included in efflciency calculations along with the friction, windage, and stray losses. The parameters

23、of the equivalent circuit can be obtained from the dc, no-load, and blocked-rotor tests .In the following, both experimental setup and Simulink/PSB models of each test are described The PSB is a useful software package to develop simulation models for power system applications in the MATLAB/Simulink

24、 environment. With its graphical user interface and extensive library, it provides power engineers and researchers with a modern and interactive design tool tobuild simulation models rapidly and easily. MATLAB and Simulink/PSB have been widely used by educators to enhance teaching of transient and s

25、teady-state characteristics of induction machines. Of course, other commercial software packages, such asMaple andMathCad, are commonly used in electrical engineering education with their advantages and disadvantages 12. The reason that MATLAB with its toolboxes was selected is that it is the main s

26、oftware package used in almost all undergraduate courses in the authors institutions as a computation tool to reinforce electrical engineering education. Therefore, students can easily access to MATLAB,and they already have the basic programming skills to use the given Simulink models and to write c

27、omputer programs when required before coming to the machinery class.The dc test is performed to compute the stator winding resisance . A dc voltage is applied to the stator windings of an induction motor. The resulting current flowing through the stator windings is a dc current; thus, no voltage is

28、induced in the rotor circuit, and the motor reactance is zero. The stator resistance is he only circuit parameter limiting current flow. Fig. 2 showsthe experimental setup of the dc test conducted at the Interconnected Power Systems Laboratory (IPSL) 13 of Drexel University. A 120-V dc power source

29、is applied to the two phasesof a Y-connected induction motor. A group of light bulbs are nstalled in the circuit as a resistive load in order to adjust dc current to the rated value. The current in the stator windings Idl and voltage across the two phases of the motor Vdc are measured. Depicts the S

30、imulink/PSB implementation of the dc test. From the PSB machine library, an induction motor block is used whose electrical parameters (such as nominal voltage and equivalent circuit parameters) and mechanical parameters (such as inertia and number of poles) can be specifled in either International S

31、ystem of Units (S.I.) or in per unit. Similar to the experimental setup, a 120-V dc source is applied to the two phases (phases A and B) of the induction motor through a series resistance, while the phase C is grounded through a resistance branch in order to have a complete electrical connection. Th

32、e purpose of the series resistance between the dc source and the induction motor is to limit the current flowing through the two windings of the motor to its rated value, which is sim ilar to the lighting bulbs used in the hardware setup of Fig. 2 Voltage and current measurement blocks measure the i

33、nstanta neous voltage across two phases and the current flowing through the windings, respectively. Two scopes display the waveform of the voltage and current, while two display boxes are used to obtain the steady-state values of the dc voltage,Vdc and current Idc.With these two measurements, the st

34、ator resistance can easily be computed asIII. COMPARISON OF EQUIVALENT CIRCUIT PARAMETERS To illustrate the effectiveness of the proposed simulaon models, one compares the equivalent circuit parameters etermined by simulations with those obtained from hardware experiments. The motors used for this p

35、urpose are the hree-phase 60-Hz Y-connected, and the 5-Horse Power (HP)nduction motors of 200-V rating 1735 r/min located at Drexel Universitys IPSL. A set of hardware experiments are rsterformed (i.e., dc, no-load, and blocked-rotor tests) on four nduction motors to obtain appropriate equivalent ci

36、rcuit paameters for software simulations. The resulting parameters are resented in Table I. For each induction motor tested the Simulink/PSB models of the dc, no-load, and blocked-rotor testswere run. The simulation data of no-load and blocked-rotor tests for motor 1 is shown inTable II, where vario

37、us quantities, such as voltage, current, and power required to compute equivalent circuit parameters, are presented. The dc test simulation data for motor 1 is as follows:Vdc=12.66V and Idl=15.74A The simulation data for the other three motors is similar to that of Motor 1 and, thus, is not given he

38、re Table III gives the equivalent circuit parameters computed,using the simulation data and the corresponding errors relative o those obtained experimentally. The error computations asume that equivalent circuit parameters determined experimenally are accurate. The results indicate that relative err

39、ors are negligible, and the proposed simulation models accurately predict equivalent circuit parameters. The largest error occurs in he stator and rotor leakage reactances, since one assumes that wo reactances have equal contributions to the blocked-rotor re-actance, which might not be the real case

40、.IV. INTEGRATION OF SIMULATION MODELS INTO ELECTRIC MACHINERY COURSES In this section, the authors describe the integration of these simulation models into electric machinery courses at two different universities, Drexel University and Nigde University,Nigde, Turkey. The Electrical and Computer Engi

41、neering (ECE) Department of Drexel University offers a pre-junior-level machine course (ECE-P 352 Electric Motor Control Principles) that concentrates on the fundamentals of electromechanical energy conversion and related control theory. This flve-hour course required for those who are in the power

42、and control track has both lecture and laboratory sections that must be taken in the same quarter. The lecture section (three hours a week) introduces students to operation principles of transformers, induction motors, dc motors, and various motor control techniques, including the power-electronics-

43、based ones. In the laboratory section (two hours a week), students are required to perform various experiments for which the necessary theoretical background is developed in the lecturesection. The experiments conducted during the term at the IPSL of Drexel University include open-circuit, short-cir

44、cuit, and load tests for transformers, speed control experiments for dcmotors, and induction motor tests. The IPSL is a computerized,small-scale, energy management system that was designed toprovide students with a hands-on learning experience about theattributes and implications involved in the man

45、agement and control of a small electric power system. With its customized graphic-intensive environment, it provides a set of experiments on the interaction of various system components in a real-life power system operating environment . In order to incorporate simulation models of induction motor t

46、ests into the course, the laboratory section is divided into two main components, each of which is a two-hour section: software laboratory and hardware laboratory. After being introduced to the theory and operating characteristics of the induction motors, including per-phase equivalent circuit and t

47、orquespeed curve and speed control methods, students simulate three induction motor tests presented in the previous section and record the data required to compute per-phase equivalent circuit parameters. A week before the software laboratory, the Simulink/PSB models of the tests and a detailed hand

48、-out describing how each model is to be simulated are made available to students. An example of the procedure showing the steps involved in simulating a no-load condition is given in the Appendix. An essential part of the software laboratory is an assignment given to students to develop a computer m

49、odel for the per-phase quivalent circuit of the induction motor using the MATLAB programming language. Using the computer program, students nvestigatemotor characteristics under varying conditions. Exmples of simulations obtained by students computer programs or the motor 1 are presented in Figs. 81

50、0. Fig. 8 shows motor quantities, such as input current and power, power factor, developed torque and power, and efficiency as a function of rotorpeed, and how these quantities are affected by a 20% drop n the supply voltage when the frequency is kept constant at he nominal value. Fig. 9 illustrates

51、 the same quantities when he frequency is reduced by 25% while the supply voltage is kept unchanged. Fig. 10 shows the torque-speed characteristic of themotor for different values of rotor resistance. Such studiesV. CONCLUSION AND FUTURE WORKIn this paper, the authors presented simulation models of

52、induction motor tests performed to obtain parameters of the per-phase equivalent circuit of three-phase induction motors.Each Simulink/PSB model is explained in detail and compared with the corresponding experimental setup. Circuit parameters obtained from simulation results are compared with those

53、obtained from hardware experiments. The error studies show that MATLAB paired with Simulink/PSB is a good simulation tool tomodel inductionmotor tests and to evaluate steady-state characteristics of the induction motor. Furthermore, a successful integration of simulation models is described in a sof

54、tware laboratory in an electric machines course, which complements classroom lecture and laboratory practice. A logical extension to the software laboratory would be to include Simulink/PSB models of experiments of transformers, dc machines, and synchronous machines so that a complete computational

55、laboratory is available to support electric machinery education.基于MATLAB/Simulink的異步電機(jī)仿真摘要本文介紹MATLAB / Simulink的實施三個異步電動機(jī)試驗，即直流，空載，和封鎖轉(zhuǎn)子測試，以確定等效電路。這些仿真模型，以支持和加強(qiáng)電子機(jī)械在本科的教育水平。在Drexel大學(xué)，費(fèi)城，賓夕法尼亞大學(xué)和尼代，尼代，土耳其的電氣機(jī)械課程。擬議的試驗已經(jīng)成功地融入電機(jī)課程。關(guān)鍵詞：教育 異步電動機(jī)，MATLAB / Simulink，電機(jī)1.引言隨著低成本的個人電腦和各種方便軟件包的興起，電腦輔助教學(xué)工具已經(jīng)成為電

56、動機(jī)械教育的一個重要組成部分的課堂講座和實驗室實驗。計算機(jī)模型和模擬的異步電動機(jī)，作為教學(xué)工具，支持課堂教學(xué)，使教師通過計算機(jī)，以容易說明穩(wěn)態(tài)運(yùn)行異步電機(jī)在各種負(fù)載條件下生成的圖形。計算工具的一部分，加強(qiáng)實驗室的實驗經(jīng)驗，提供學(xué)生有機(jī)會來驗證實驗結(jié)果，比較他們獲得的計算機(jī)模擬圖形。 這種比較的機(jī)會幫助學(xué)生認(rèn)識的局限性，硬件實驗，而且作為一個計算機(jī)模型不能代替實際的硬件實驗，因為一些模型假設(shè)可能并不完全代表了操作的異步電動機(jī)。電動機(jī)械課程，本科課程一般包括教室和實驗室課節(jié)。課堂節(jié)涵蓋的穩(wěn)態(tài)運(yùn)行的異步電動機(jī)，其中每相的等效電路是用于計算各種汽車的數(shù)量，如輸入電流和功率，功率因數(shù)，發(fā)達(dá)國家扭矩和效率

57、。相關(guān)的計算與穩(wěn)態(tài)運(yùn)行需要的知識，等效電路參數(shù)。這些參數(shù)都得到了履行三項測試，即直流，無負(fù)載，并阻止轉(zhuǎn)子試驗電機(jī)在一個典型的實驗。該實驗室的部分包括這些測試和負(fù)載實驗，讓學(xué)生熟悉異步電動機(jī)運(yùn)行、硬件和測量并獲得了寶貴的經(jīng)驗。作者的經(jīng)驗表明，在教學(xué)上卓克索大學(xué)，賓州費(fèi)城，當(dāng)他們來到實驗室進(jìn)行這些實驗，即使相應(yīng)的理論，廣泛覆蓋在課堂上，給它們至少一節(jié)課詳細(xì)描述出實驗室設(shè)施和程序的實驗，學(xué)生普遍有困難。與他們之前的其他實驗室相比，學(xué)生不熟悉實驗室環(huán)境，其中包含大量的機(jī)器和相對復(fù)雜的測量方法和設(shè)備。時間限制在實驗室工作，也是一個艱難的調(diào)整。在通常的兩小時的實驗課，學(xué)生必須建立和執(zhí)行四個感應(yīng)電機(jī)的實驗中，采取必要的測量，并調(diào)查穩(wěn)態(tài)性能的電動機(jī)在各種工況.由于時間的限制，學(xué)生往往急于通過實驗，以完成他們的時候，不幸的是使他們獲得真正的感覺電機(jī)運(yùn)行和升值所取得的成就在實驗室實踐。因此，在學(xué)生來實驗室，仿真工具必須制定異步電動機(jī)試驗充當(dāng)有益的籌備工作。本文的目的是以設(shè)計一個計算實驗室，介紹這些仿真模型的異步電機(jī)實驗。直流，無負(fù)載，并阻止轉(zhuǎn)子模擬模型的開發(fā)作為單獨(dú)的應(yīng)用程序中使用MATLAB / Simulink的和電氣系統(tǒng)模塊（PSB）。在負(fù)載實驗中，學(xué)生必須寫一個計算機(jī)程序利用MATLAB的M -文件編程的每相的等