EXPERT SYSTEMS AND SOLUTIONS

Email: expertsyssol@gmail.comexpertsyssol@yahoo.comCell: 9952749533

www.researchprojects.info PAIYANOOR, OMR, CHENNAI

Call For Research Projects Final year students of B.E in EEE, ECE, EI, M.E (Power Systems), M.E (Applied

Electronics), M.E (Power Electronics)Ph.D Electrical and Electronics.

Students can assemble their hardware in our Research labs. Experts will be guiding the

projects.

Control of Induction MotorControl of Induction Motor

Under the GuidanceUnder the Guidanceof of

Prof.Pramod AgarwalProf.Pramod AgarwalDr.Sumit Ghatak ChoudhriDr.Sumit Ghatak Choudhri

INTRODUCTION TO VECTORINTRODUCTION TO VECTOR

Nikola Tesla in 1880 introduced the concept of Nikola Tesla in 1880 introduced the concept of PolyPhase Induction Machine, from which the PolyPhase Induction Machine, from which the world has witnessed continued growth in the use world has witnessed continued growth in the use of Induction Machine of Induction Machine Three phase induction motors has been mainly Three phase induction motors has been mainly preferred for is simplicity, robustness and preferred for is simplicity, robustness and maintenance free operationmaintenance free operationBut for variable speed drive normally D.C drives But for variable speed drive normally D.C drives are preferred . The main problem with D.C are preferred . The main problem with D.C drives is the time to time maintenance of the drives is the time to time maintenance of the commutators, brushes and brush holders commutators, brushes and brush holders

Problems with scalar ControlProblems with scalar Control

At frequencies higher than the rated value, At frequencies higher than the rated value, the constant V/Hz principle also have to be the constant V/Hz principle also have to be violated because, to avoid insulation break violated because, to avoid insulation break down, the stator voltage must not exceed down, the stator voltage must not exceed its rated value its rated value

WHAT IS VECTOR CONTROLWHAT IS VECTOR CONTROL

Vector control mode is defined as a control Vector control mode is defined as a control technique in which two equivalent control signals technique in which two equivalent control signals are produced to control Flux and Torque in are produced to control Flux and Torque in decoupled Manner.decoupled Manner.both the magnetic field and the torque both the magnetic field and the torque developed in the motor can be controlled developed in the motor can be controlled independently;independently;Optimal conditions for torque productions, Optimal conditions for torque productions, resulting in the maximum torque per unit resulting in the maximum torque per unit ampere, occur in the motor both in the steady ampere, occur in the motor both in the steady state conditions and transient conditions of an state conditions and transient conditions of an operation.operation.

Direct and Indirect Direct and Indirect

Direct MethodDirect Method

hall effect hall effect transducers are used transducers are used to obtain rotor fluxto obtain rotor flux

Indirect MethodIndirect Method

no direct no direct measurement is done measurement is done but a larger but a larger computation is used computation is used

Typical hardware layout of FOC Typical hardware layout of FOC systemsystem

V/F CONTROLV/F CONTROL

Problems with scalar Problems with scalar ControlControl

At frequencies higher At frequencies higher than the rated value, the than the rated value, the constant V/Hz principle constant V/Hz principle also have to be violated also have to be violated because, to avoid because, to avoid insulation break down, insulation break down, the stator voltage must the stator voltage must not exceed its rated value not exceed its rated value

SPACE PHASORSPACE PHASOR

Clarke TransformationClarke Transformation

PARK TRANSFORMATIONPARK TRANSFORMATION

PHASOR DIAGRAM OF VECTOR PHASOR DIAGRAM OF VECTOR CONTROLCONTROL

Flux Orientation MethodsFlux Orientation Methods

Rotor flux orientationRotor flux orientation It gives a natural decoupling controlIt gives a natural decoupling control

Stator flux orientationStator flux orientation It gives a coupling effect which needs to be It gives a coupling effect which needs to be

compensated by a decoupling compensation compensated by a decoupling compensation currentcurrent Air gap flux orientationAir gap flux orientation

It gives a coupling effect which needs to be It gives a coupling effect which needs to be compensated by a decoupling compensation compensated by a decoupling compensation current current

PWM MERITS AND DEMERITSPWM MERITS AND DEMERITSMERTSMERTS

Relatively simple and robust Power circuitRelatively simple and robust Power circuitLow Manufacturing CostLow Manufacturing CostSimple Voltage and Current Control techinquesSimple Voltage and Current Control techinques

DemeritsDemerits Most PWM inverters operate at low and medium Most PWM inverters operate at low and medium

switching frequency levels; a reason for this is that switching frequency levels; a reason for this is that such converters need to switch rapidly to minimize such converters need to switch rapidly to minimize loss. Any attempt to increase switching frequencies loss. Any attempt to increase switching frequencies will also follow in an increase of switching loss and an will also follow in an increase of switching loss and an increase in the generation of electromagnetic increase in the generation of electromagnetic interference. interference.

Speed ControllerSpeed Controller

ω ω e (n)e (n) = ω = ω nn* - ω * - ω nn

Speed Controller takes speed error as input Speed Controller takes speed error as input and output Torque Valueand output Torque Value

Types of Speed ControllersTypes of Speed ControllersPI ControllerPI ControllerPID ControllerPID ControllerFuzzy ControllerFuzzy Controller

PI controllerPI controller

K K PP and K and K ii are are

proportional and integral proportional and integral gain parameters of the gain parameters of the PI speed controller PI speed controller

T (n) = T (n-1) * + KP [ω re (n) - ω re(n-1) ] + K i ω re (n)

PID ControllerPID Controller

T (n) = T (n-1) * +KP [ω re(n) - ω re(n-1) ] + K i ω re(n) + K d [ω re (n) - 2 ω re(n-1) + ω re(n-2) ]

Fuzzy Logic ControllerFuzzy Logic Controller

ModellingModelling

ModelingModeling

The Concept of Space VectorThe Concept of Space Vector

BLOCK DIAGRAM OF INDUCTION BLOCK DIAGRAM OF INDUCTION MOTORMOTOR

SPEED SENSORLESS DRIVESPEED SENSORLESS DRIVE

Reduction of HardwareReduction of Hardware

Increased Mechanical robustnessIncreased Mechanical robustness

Higher reliabilityHigher reliability

Unaffected machine InertiaUnaffected machine Inertia

INDUCTION MOTORINDUCTION MOTOR

DOL STARTER MODEL IN DOL STARTER MODEL IN MATLABMATLAB

SIMULATED STARTING RESPONSE OF A 1HP MACHINE

0.5 0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95 1-500

0

500Stator Voltage

Van

,Vb

n,V

cn

0.5 0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95 1-20

0

20Stator Currents

Ia

Ib

Ic

0.5 0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95 10

2000

4000Speed

Wm

0.5 0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95 1-20

0

20Torque

TL

T

E

Time --->

REVERSAL and RE-REVERSAL

1 1.2 1.4 1.6 1.8 2 2.2 2.4 2.6 2.8 3-500

0

500Stator Voltage

Van

,Vbn

,Vcn

1 1.2 1.4 1.6 1.8 2 2.2 2.4 2.6 2.8 3-20

0

20Stator Currents

Ia I

b Ic

1 1.2 1.4 1.6 1.8 2 2.2 2.4 2.6 2.8 3-5000

0

5000Speed

Wm

1 1.2 1.4 1.6 1.8 2 2.2 2.4 2.6 2.8 3-50

0

50Torque

TL T

E

Time --->

Load Perturbations

3 3.2 3.4 3.6 3.8 4 4.2 4.4 4.6 4.8 5-500

0

500Stator Voltage

Van

,Vb

n,V

cn

3 3.2 3.4 3.6 3.8 4 4.2 4.4 4.6 4.8 5-5

0

5Stator Currents

Ia

Ib

Ic

3 3.2 3.4 3.6 3.8 4 4.2 4.4 4.6 4.8 50

2000

4000Speed

Wm

3 3.2 3.4 3.6 3.8 4 4.2 4.4 4.6 4.8 5-5

0

5Torque

TL

T

E

Time --->

LITERATURE SURVEYLITERATURE SURVEYF. Blaschke, ”The principle of field orientation as applied to the new TRANSVEKTOR closed-loop control for F. Blaschke, ”The principle of field orientation as applied to the new TRANSVEKTOR closed-loop control for rotating field machines,” rotating field machines,” Siemens ReviewSiemens Review, pp. 217-220, 1972., pp. 217-220, 1972.G.Diana, R.G. Harley, “ An aid for teaching field oriented control applied to Induction Machines,” G.Diana, R.G. Harley, “ An aid for teaching field oriented control applied to Induction Machines,” IEEE Trans. IEEE Trans. on Power Systemson Power Systems, Vol. 4, no.3, pp.1258-1262, Aug 1989, Vol. 4, no.3, pp.1258-1262, Aug 1989James A. Norris, “ Vector Control of A.C Motors,” James A. Norris, “ Vector Control of A.C Motors,” in Proc. 1993 IEEE Textile, Fibre and Film Industry in Proc. 1993 IEEE Textile, Fibre and Film Industry Technical ConfTechnical Conf., pp. 3/1 – 3/8.., pp. 3/1 – 3/8.W.Leonard, “ Field Oriented for Controlling AC Machine-Principle and Applications,” W.Leonard, “ Field Oriented for Controlling AC Machine-Principle and Applications,” in Proc. 1988 Power in Proc. 1988 Power Electronics and variable Speed Drives ConfElectronics and variable Speed Drives Conf ., pp.277-282., pp.277-282B.K.Bose, B.K.Bose, Power Electronics and A.C DrivesPower Electronics and A.C Drives, New Jersey, Prentice-Hall, 1986, New Jersey, Prentice-Hall, 1986P.C Krause, P.C Krause, Analysis of Electrical machineryAnalysis of Electrical machinery, New York; McGraw-Hill 1986., New York; McGraw-Hill 1986.J. Murphy and E Turnbull, PJ. Murphy and E Turnbull, Power Electronic control of A.C Motors.ower Electronic control of A.C Motors. Oxford,U.K., Pergamon Press, 1988. Oxford,U.K., Pergamon Press, 1988.S.Yamamura, S.Yamamura, AC Motor for High Performance Applications, Analysis and ControlAC Motor for High Performance Applications, Analysis and Control , New York, Marcel dekker, , New York, Marcel dekker, 19861986R.Krishnan, R.Krishnan, Electric Motor Drives Modeling Analysis and ControlElectric Motor Drives Modeling Analysis and Control , Pearson Education, New Delhi, India, 2003 , Pearson Education, New Delhi, India, 2003J.W.Finch, “ Scalar and vector : a simplified treatment of induction motors performance,” J.W.Finch, “ Scalar and vector : a simplified treatment of induction motors performance,” in Proc. 1998 IEE in Proc. 1998 IEE vector control colloquiumvector control colloquium, pp2/1- 2/4., pp2/1- 2/4.C.C Lee, “ Fuzzy logic on Control System Part-I,” C.C Lee, “ Fuzzy logic on Control System Part-I,” IEEE Trans. on Systems, Manual CyberneticsIEEE Trans. on Systems, Manual Cybernetics , vol.20, no.2, , vol.20, no.2, pp.404-418, Mar/Apr 1990pp.404-418, Mar/Apr 1990C.C Lee, “ Fuzzy logic on Control System Part-II,” C.C Lee, “ Fuzzy logic on Control System Part-II,” IEEE Trans. on Systems, Manual CyberneticsIEEE Trans. on Systems, Manual Cybernetics , vol.20, no.2, , vol.20, no.2, pp.404-418, Mar/Apr 1990pp.404-418, Mar/Apr 1990 Hellendoom H. and C. Thomas, “Defuzzifications in Fuzzy controllers”, Intelligence and Fuzzy Systems, Vol. Hellendoom H. and C. Thomas, “Defuzzifications in Fuzzy controllers”, Intelligence and Fuzzy Systems, Vol. 1, 28-30 1996. pp. 109-123, 1993.1, 28-30 1996. pp. 109-123, 1993. B.N.Singh, “Investigations on vector Controlled Induction Motor Drive,” Ph.D dissertation, Dept. of Electrical B.N.Singh, “Investigations on vector Controlled Induction Motor Drive,” Ph.D dissertation, Dept. of Electrical Eng., Indian Institute of Technology, Delhi. India. 1995. Eng., Indian Institute of Technology, Delhi. India. 1995. S.Ghatak Choudhuri, “Analysis and Development of vector Control of Induction Motor Drive,” Ph.D S.Ghatak Choudhuri, “Analysis and Development of vector Control of Induction Motor Drive,” Ph.D dissertation, Dept. of Electrical Eng., Indian Institute of Technology, Delhi. India. 2004. dissertation, Dept. of Electrical Eng., Indian Institute of Technology, Delhi. India. 2004.