基于MATLABSimulink的异步电机仿真.docx

1、基于MATLABSimulink的异步电机仿真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

2、 circuitparameters. These 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 T

3、ermsEducation, induction 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 el

4、ectrical machinery education 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 .F

5、or personal use only in study and research; not for commercial use The computational tools 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 simu

6、lations.Such a comparison opportunity helps students realize the limitations of hardware experiments 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 a

7、ssumptions.Moreover, an undergraduate electric machinery course that integrates up-to-date 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,

8、 possibly attracts more students. Electrical machinery courses at the undergraduate level 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

9、quantities, such as input current and power, power factor, developed torque, and efflciency. 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, andFor persona

10、l use only in study and research; not for commercial useblocked-rotor tests on the motor in a typical laboratory experiment. The laboratory section includes these tests and a load experment that allows students to become familiar with the inducion motor operation and to gain invaluable hardware and

11、measurement experiences. The authors experience while teaching nduction motors at Drexel University, Philadelphia, PA, indicates that students generally have difflculty when they come to he laboratory to carry out these experiments even though the corresponding theory is extensively covered in the c

12、lassroomsection with a detailed hand-out describing laboratory facilitiesand the procedure of the experiments, given to them at least a week before the laboratory. Students are not familiar with a laboratory environment that contains large machines and relatively complex measurement methods and devi

13、ces as compared with other laboratories they have been to before. The time constraints during the laboratory exercise are also a difflcult adjustment. In a usual two-hour laboratory section, students are required to set up and perform four induction motor experiments, to take the necessary measureme

14、nts, and to investigate steady-state performance of the motor under various loading conditions. Because of the time limitations, students often rush through the experiments in order to flnish them on time, which unfortunately prevents them from getting a true feeling of motor operation and rom appre

15、ciating what has been accomplished during the laboratory practice.Therefore, simulation tools must be developed for induction motor experiments to serve as useful preparatory exercises before students come to the laboratory. The objective of this paper is to present simulation models of these induct

16、ion motor experiments in an effort to design a computational laboratory.The dc, no-load, and blocked-rotor simulation models are developed as stand-alone applications using MATLAB/Simulink and Power System Blockset (PSB) . For the load experiment, students are required to write a computer program us

17、ing MATLABs M-flle programming for the per-phase equivalent circuit of the induction motor to compute operating quantities.Such an assignment improves students programming skills that would be helpful in other classes as well. The remainder of the paper is organized as follows. Section II describes

18、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 how these tests are conducted and how the corresponding measurements are used to compute the equivalent circuit parameters. Then, for each test,

19、the corresponding Simulink/PSB model is presented and compared with the actual experimental setup emphasizing the similarities and discrepancies. Section III compares the equivalent circuit parameters determined using simulation data and data obtained from experiments. Section IV explains how to int

20、egrate these simulation models into undergraduate electric machine courses at two different universities, while the last section concludes the paper. II. INDUCTION MOTOR TESTS:EXPERIMENTAL SETUPS AND SIMULINK/PSB MODELSThe steady-state operating characteristics of a three-phase induction motor are o

21、ften investigated using a perphase equivalent circuit as shown in Flg. In this circuit,R1 and X1 represent stator resistance and leakage reactance, respectively;R2 and X2 denote the rotor resistance and leakage reactance referred to the stator, respectively;RC resistance stands for core losses;XM re

22、presents magnetizing reactance; and S denotes the slip. The equivalent circuit is used to facilitate the computation of various operating quantities, such as stator current, input power, losses, induced torque, and efciency. When power as pects of the operation need to be emphasized, the shunt resis

23、tance(Rc)is usually neglected; the core losses can be included in efflciency calculations along with the friction, windage, and stray losses. The parameters of the equivalent circuit can be obtained from the dc, no-load, and blocked-rotor tests .In the following, both experimental setup and Simulink

24、/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 environment. With its graphical user interface and extensive library, it provides power engineers and researchers with a modern and interactiv

25、e design tool tobuild simulation models rapidly and easily. MATLAB and Simulink/PSB have been widely used by educators to enhance teaching of transient and steady-state characteristics of induction machines. Of course, other commercial software packages, such asMaple andMathCad, are commonly used in

26、 electrical engineering education with their advantages and disadvantages 12. The reason that MATLAB with its toolboxes was selected is that it is the main software package used in almost all undergraduate courses in the authors institutions as a computation tool to reinforce electrical engineering

27、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 computer programs when required before coming to the machinery class.The dc test is performed to compute the stator winding resisance . A dc vol

28、tage 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 induced in the rotor circuit, and the motor reactance is zero. The stator resistance is he only circuit parameter limiting current flow. Fig. 2

29、 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 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 t

30、o 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 Simulink/PSB implementation of the dc test. From the PSB machine library, an induction motor block is used whose electrical parameters (such as

31、nominal voltage and equivalent circuit parameters) and mechanical parameters (such as inertia and number of poles) can be specifled in either International System 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

32、 induction motor through a series resistance, while the phase C is grounded through a resistance branch in order to have a complete electrical connection. The purpose of the series resistance between the dc source and the induction motor is to limit the current flowing through the two windings of th

33、e 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 instanta 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