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SPEED CONTROL OF SEPARATELY EXCITED DC MOTOR USING NEURO FUZZY TECHNIQUE

• Muhammed sajid• Augustin Fidalis• Sajina• Sufina• Ramsi• Jumana

MAIN OBJECTIVE

• This project Focusses on NEURO FUZZY TECHNIQUE in estimating speed and controlling it for a separately

excited DC motor.

• A neuro fuzzy control scheme consists of two parts

1)neural identifier 2)fuzzy logic controller • The purpose of this technique is to achieve accurate

trajectory control of the speed.

INTRODUCTION

• Various applications of DC motors. • Why DC drives are used in industrial

applications? • In these applications, the motor should be

precisely controlled to give the desired performance.

• Conventional methods of Speed control of dc motors.

• The proposed controller systems consist of multi-input fuzzy logic controller (FLC) and multi-input integrated fuzzy logic controller (IFLC) for the speed control

Many practical control issues

• Variable and unpredictable inputs • Noise propagation along a series of unit

processes • Unknown parameters • Changes in load dynamics

Advantages of using neuro fuzzy technique

• Fast adaptation • High degree of tolerance • Smooth operation • Reduce the effect of Non-linearity • Learning ability • Inherent approximation capability

Block diagram of separated excited dc motor

First phase

• This project first focussed on implementing PI controller & IP controller to control speed of a dc motor.

Block diagram of separated excited dc motor for speed control

Block diagram of separated excited dc motor for PI speed controller

SIMULINK MODEL OF PI CONTROLLER

Block diagram of separated excited dc motor for IP speed controller

SIMULINK MODEL OF IP CONTROLLER

Transfer Fcn

1

.0465 s+.004Scope 1

Integrator

1s

Gain 91.5

Gain 8

1

Gain 7

.55

Gain 6

.55

Gain 5

-K-Gain 4

13

Gain 3

1

Gain 2

1

Gain 1

30

Constant 1

25

Constant

1500

Motor’s Parameters

• The motor used in this experiment is dc separately excited,rating 2.5hp at rated voltage 110 V, and the motor’s parameters are as follows:

• Armature resistance (Ra) = 0.6 Ω• Armature inductance (La) = 8 mH• Back e.m.f constant (K) = 0.55 V/rad/s• Mechanical inertia (J) = 0.0465 kg.m2• Friction coefficient (B) = 0.004 N.m/rad/s• Rated armature current (Ia) = 20 A

Simulation result for PI controller

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 20

200

400

600

800

1000

1200

1400

1600

1800

2000speed response of PI controller

time in seconds

speed in r

pm

Simulation result for IP controller

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 20

200

400

600

800

1000

1200

1400

1600

time in seconds

speed in r

pm

speed response of IP controller

Comparison between PI controller and IP controller

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 20

200

400

600

800

1000

1200

1400

1600

1800

2000

time in seconds

speed in r

pm

speed response of PI & IP controller

IP controller

PI controller

RESULTS AND DISCUSSIONS

• PI controller maintaining a zero study state error

• PI controller have the disadvantages as High starting over shoot,Sluggish response, Sensitivity

• IP controller have the advantages as reduction of peak over shoot

• Inorder to avoid the limitations of IP controller fuzzy is introduced

Second Phase

Fuzzy logic theory and the design concepts

CONCLUSION

IP controller provide important advantages over the traditional PI controller like limiting the overshoot in speed,thus the starting current over shoot can be reduced.

REFERENCES[1] J.S.R.Jang, “ANFIS: Adaptive Network Based Fuzzy InferenceSystem”, IEEE, Transactions on

system, Man & cybernetics, volume23, May/June 1993.[2] J.S.R.Jang, C.T.Sen, “Neuro-Fuzzy Modeling &Control”,Proceedings of IEEE, volume 83, No.3,

March 1995.[3] S.Aydemir, S.Sezen, H.M.Ertunc, “Fuzzy logic speed control of DCmotor”, IEEE, volume 2,

August 2004, PP 766-771.[4] “Speed Control of separately Excited DC Motor”, MoleykuttyGeorge, American JournalApplied

Science[5] “Fundamentals of Electrical Drives”, Gopal K.Dubey, Narosa Publishers 2nd Edition.[6] “Electric Motor drives modeling, Analysis and control”, R.Krishnan,Prentice-Hall of India

Private Limited, New Delhi.[7] The Mathworks Inc., MATLAB/SimPower Systems Demos/Chopperfed DC Motor Drive.

[8] “Modern Power Electronics and AC Drives”, B.K.Bose NJ: Prentice Hall, 2002. ISSN 1546-9239 I

2008 Science publications.