1. Simulation of Electrical Machines, drives and Control using software tools
Dr. B. Umamaheswari
Professor
Dept of Electrical & Electronics Engineering,
College of Engineering Guindy
Anna University Chennai
Programs linked in the enclosed slides can be run in MATLAB-SIMULINK platform

2. The Teaching and Learning Process
An Effective Teaching-Learning Process may require the following 5-step sequence
OPTRA
O Organising
P Preparation
T Transmission
R Reception
A Assimilation
Let us present this lecture in these 5-steps
Dr. B. Umamaheswari, Anna University

3. Organizing
The theory of electrical machines is best explained with analytical models and equivalent circuits. Hence with the help of software tools these concepts can be best explained.
Let us start with the following questions
Why do we need tools like MATLAB?
How, where and when do we these tools?
To what level do we use these tools?
Dr. B. Umamaheswari, Anna University

4. Use of software tools like MATLAB & SIMULINK
Best used when the theory requires support of analytical expressions i.e. in the form of mathematical equations
The equations could be
static or dynamic
Linear or non-linear
Descriptive or symbolic
Deterministic or stochastic
Dr. B. Umamaheswari, Anna University

5. Benefits of using software tools
To have better understanding of the operating principles
To visualise the characteristics under various operating conditions
To experiment on favourable and non-favourable conditions
To design and test the machines for achieving improved performance
To create a working platform for pre-determining the characteristics
Dr. B. Umamaheswari, Anna University

6. Level of Usage
Digital simulation for complete functional testing -MATLAB/SIMULINK
Hardware in Loop (HIL) simulation for real time testing of the controller –RTW and DAQ
Power Hardware in Loop Simulation (PHIL) for real time testing of the Power Electronics and Controller - RTW and DAQ
Embedding the control algorithm on a real time embedded target platform – RT Target link module
Dr. B. Umamaheswari, Anna University

7. Suitability of the tool for Electrical Drives and Control
Fields involved
Electrical Machines
Power Electronics
Control Theory and
embedded platforms
Study involves understanding of analytical expressions .
Simulation of experimental conditions and research developments is possible.
Dr. B. Umamaheswari, Anna University

8. Topics for Presentation
Let us discuss the following topics using software tools
Electro-Magnetics
Electro-mechanics
DC Machines
AC Machines
Dr. B. Umamaheswari, Anna University

9. 1. Electro-Magnetics
Under Electro-magnetics the following topics are to be discussed.
Magnetic circuit – the linear relationship
Electrical Equivalent
Inductance
Rotating magnetic field
Use software tools for teaching and research
Dr. B. Umamaheswari, Anna University

10. Magnetic circuit The Amphere’s Law
A current carrying coil produces magnetic field whose intensity is decided by the permeability of the medium through which the flux passes through.
BH-curve describes the permeability of a medium
For linear assumption Permeability is constant
Dr. B. Umamaheswari, Anna University

11. Electrical equivalent
For the purpose of analysis, an equivalent electrical circuit can be drawn.
Flux => current
MMF => emf
Reluctance => Resistance
Linear BH- relationship Program1
Non-linear BH relationship
program2
Dr. B. Umamaheswari, Anna University

12. Linear case Linear BH- relationship Air gap reluctance is Rg
Core Reluctance is Rl << Rg
Using voltage division rule, the greater Reluctance part gets the greater MMF sahre
Hence upon the supplied MMF ‘Ni” most of the MMF is dropped or available across the air-gap
Program1 describes the flux variation (equation 1) as a function of airgap length.
Program1
Dr. B. Umamaheswari, Anna University

13. Non-Linear case Non-linear BH relationship
Core reluctance is a function of flux
Use equation (3) to get Hl for various values of Bg.
Superimpose the obtained Hl vs Bg characteristics on the BH curve to get Hl and Bg of the given circuit.
Use Program2 to see the results.
program2
Dr. B. Umamaheswari, Anna University

14. Inductance
Self Inductance of a coil describes how much of the flux links the coil produced by its own current
Mutual inductance of a coil describes how much of the flux links the coil produced by current in the other coils.
Inductance in a salient pole machine is simulated using the following program
MATLAB Program
Dr. B. Umamaheswari, Anna University

15. Generation of Sinusoidal MMF
With two sets of coils of carrying currents in the opposite directions Square -MMF waveshape can be produced.
Using appropriate Fourier relationship the square wave can be resolved into fundamental and its harmonic components .
Dr. B. Umamaheswari, Anna University

16. Rotating magnetic field
Rotating magnetic field can be produced by Two, Three or more phases equally placed along the periphery of a circular path
Rotating MMF of Two phase and Two pole machine is illustrated in the following program
MATLAB Program
Dr. B. Umamaheswari, Anna University

17. Electro-mechanics
A coil (Armature) placed in the airgap subjected to time-varying magnetic field experiences an induced voltage { Faraday’s Law}
It circulates current to oppose its cause (Lenz aw)
Interaction of magnetic flux with armature current produces mechanical force
Direction of force is given by Fleming’s Left Hand Rule.
This is the principle of motoring
Dr. B. Umamaheswari, Anna University

18. Principle of Motoring & Generation
Dr. B. Umamaheswari, Anna University

19. Simulation of DC Machine characteristics
Equivalent circuit of DC machine with separate excitation is illustrated in the figure
Using software simulation the characteristics can be studied
Dr. B. Umamaheswari, Anna University

20. MATLAB CODING DC MOTOR EQUIVALENT CIRCUIT
Dr. B. Umamaheswari, Anna University

21. Separately excited Torque speed characteristics Matlab model
Matlab code
Dr. B. Umamaheswari, Anna University

22. Other EXCITATION SCHEMES
Dr. B. Umamaheswari, Anna University

23. Load Profiles
Dr. B. Umamaheswari, Anna University

24. Series excited Torque speed characteristics Matlab model Matlab code
Dr. B. Umamaheswari, Anna University

25. Simulation DC-Chopper performance
Program_Chopper
Dr. B. Umamaheswari, Anna University

26. Chopper fed DC Drive MATLAB program
Dr. B. Umamaheswari, Anna University

27. Closed loop PI Control of Chopper fed DC motor
Matlab model
Dr. B. Umamaheswari, Anna University

28. Induction Machine Steady state Equivalent circuit
Dr. B. Umamaheswari, Anna University

29. Three Phase Induction machine
Circle diagram can be obtained using the following program to predetermine the steady stae characteristics
Circle diagram
Dr. B. Umamaheswari, Anna University

30. 3ф INDUCTION MOTOR
Torque speed characteristics can be obtained using the following program
MATLAB CODE
MATLAB MODEL
Dr. B. Umamaheswari, Anna University

31. SINGLE PHASE IM Closed Loop Speed control V/F control
Dr. B. Umamaheswari, Anna University

32. References Electric Drives by Ion Boldea and S.A. Nasar
Electrical Machines by Nagrath and Kothari
Electrical Machines by Fitzerald and Kingsley
Power Electronics by B. K. Bose
Control Systems Engineering by I. J. Nagrath and M. Gopal
Dr. B. Umamaheswari, Anna University

33. Thank You B. Umamaheswari Professor
Department of Electrical and Electronics Engineering
Anna University Chennai
This lecture material serves as s a supplement for learning electrical machines , drives and control for an advanced learner
Dr. B. Umamaheswari, Anna University