“DESIGN AND DEVELOPMENT OF CHOPPER CONTROL SLIP RING INDUCTION MOTOR DRIVE”

By

Suman KarmakarEnrolment No: - 0820312

Under The Guidance ofMrs. Anindita Jamatia, Assistant Professor

Electrical Engineering DepartmentN.I.T. Agartala

&

Dr. Mainak Sengupta, Assistant ProfessorBengal Engineering & Science University,

Howrah, West Bengal.

PRESENTATION OUTLINE

1. INTRODUCTION ON SRIM DRIVES

2. DETERMINATION OF M/C PARAMETERS

3. EXPERIMENT ON SPEED CONTROL OF SRIM by varying the slip which involves varying the rotor resistance

4. SIMULATION FOR PULSE WIDTH MODULATOR CIRCUIT

5. DESIGN AND DEVELOPMENT OF CONTROL CIRCUIT AND DRIVER CIRCUIT

7. ANALYSIS OF CHOPPER CONTROL LED SRIM DRIVE

8. CONCLUSION AND FUTURE SCOPE

PROS AND CONS OF AC MOTOR DRIVES

Advantages : Lightweight (20% to 40% lighter than equivalent DC motor) InexpensiveLow maintenance

Disadvantages Power control relatively complex and more expensive

Effective turns ratio easy to determined for a slip ring IM than cage rotor motor

Torque-speed characteristic of SRIM can be modified, which is not possible in cage rotor IM .

SCIM has small starting torque, large starting current & poor starting power factor

Advantages of SRIM OVER SCIM

Desired Motor Characteristic

Should behave: like the high-resistance wound-rotor curve; at high slips, & like the low-resistance wound-rotor curve at low slips

Speed Control of Induction Motor

1. Induction Motor Speed Control by Pole Changing. 2. Speed Control by Changing the Line Frequency. 3. Speed Control by Changing the Line Voltage. 4. Speed Control by Changing the Rotor Resistance.

Stator Voltage Control

Td

IMAC

VariableVoltageSources

Vs

Tmax

S=0s

Ns

S=1

TL

Nm =0

Td

Vs1Vs Vs2> >

12

Tst

Tst1

Tst2

Frequency Voltage Control

Td

IM

ACVariableVoltageSources

Vs

f

Tmax

S=0S=1

TL

m =0

Td

< <

1 2

TstTst1

Tst2

s

fsS=0fs1fs2

S=0

fs2 fsfs1

Three-phasesupply

Rotor

Stator

RX

RX

RX

Rotor Resistance control

RATING OF THE COUPLED MOTOR –GENERATOR SET & IM PARAMETERS:

Induction Motor: 3 H.P, 415 V, 4.7 A, Winding- Stator- Y- 415 V, 4.7 A Rotor- Y- 185 V, 7.5 A

DC m/c : 2 KW, 220 V, 9 A, 1500 rpm, Shunt, 220 V, 0.7 A.

TESTS performed to Determine M/C Model Parameters,

The No-Load Test (result compare with synchronous Test) The DC Test The Locked-Rotor TestMoment of inertia test

Pcore,loss = 161.7165 ohm RC = 1757 ohm Xm = 46.937 ohm.

X ‘lr = Xls = 25.5 ohm rs = 4.95 ohm ;

r ‘r = 2.4439

ohm.

B =1.6649 * 10-3 N-m

Jeach,m/c = 8.9357* 10-6 Kg-m2

CONTROLLING WOUND ROTOR INDUCTION MOTOR SPEED BY VARYING THE SLIP USING ROTOR RESISTANCE CONTROL

Speed control by three external resistances on rotor circuit.

Speed control by Diode Rectifier and Single external resistance on rotor circuit

Speed control by Diode Rectifier and Single resistance with a Chopper on rotor circuit

METHOD-1 CONTROLLING INDUCTION MOTOR SPEED USING EXTERNAL ROTOR RESISTANCES

Three-phasesupply

Rotor

Stator

RX

RX

RX

Speed

In rpm

Rotor External

Resistance (Rex)

Total Equ.

Resistance

RT,eq

Vr,L-L Ir

1188

RA= 82 Ω

RB = 54 Ω

Rc = 65 Ω

= RA+ RB+ Rc

= 201 Ω44 V 0.40

1238

RA= 44.5 Ω

RB = 40 Ω

Rc = 47.5 Ω

= RA+ RB+ Rc

= 132 Ω34 V 0.42

1336

RA= 30.7 Ω

RB = 23 Ω

Rc = 27.7 Ω

= RA+ RB+ Rc

= 81.420 V 0.45

METHOD 2: SPEED CONTROL BY DIODE RECTIFIER AND SINGLE EXTERNAL RESISTANCE ON ROTOR CIRCUIT ( WITH A DC LINK INDUCTOR)

Speed

In rpm

Rotor External

Resistance (Rex)Vdc Idc

1188 108 Ω 49 V 0.555 A

1238 80.5 Ω 44 V 0.57 A

1336 56.56 Ω 21 V 0.59 A

1488 nil 0.4 V 0.62 A

755 242 Ω 130 V 0.49 A

METHOD 3: SPEED CONTROL BY DIODE RECTIFIER AND SINGLE RESISTANCE WITH A CHOPPER ON ROTOR CIRCUIT

58 0.6 27.43 1158

44 0.612 45.7 1238

34 0.62 58.9 1306

Rotor rectified DC voltage (Vdc)

DC link Current( Idc)

Duty Ratio (%) Speed of the rotor

,Switching frequency

Rotor rectified

DC voltage

(Vdc)

DC link Current

( Idc)

Duty Ratio (%)

Speed of the rotor

Remarks

fsw = 2.54 KHz

76 0.54 ---------- 1060MOSFET Switched

off

70 0.58 14.22 1104MOSFET

ON

58 0.6 27.43 1158MOSFET

ON

44 0.612 45.7 1238MOSFET

ON

34 0.62 58.9 1306MOSFET

ON

fsw=4.6296 KHz

76 0.52 --------- 1060 MOSFET off

66 0.58 9.26 1104MOSFET

ON

56 0.58 25.92 1140MOSFET

ON

38 0.59 50 1262MOSFET

ON

27 0.62 66.66 1320MOSFET

ON

fsw=3.7879KHz

58 0.56 21.21 1128MOSFET

ON

44 0.60 40.9 1218MOSFET

ON

30 0.6125 62.12 1304MOSFET

ON

Pulse width modulator circuit

Orcad Simulation for Pulse width modulator circuit

Out put wave form of Op-amp, VA , Square wave

Out put wave form of Op-amp VB = Bipolar triangular wave

Out put wave form of Op-amp, VC ,Unipolar triangular wave

Out put wave form of Op-amp ,VD ,P.W.M square pulse

The Oscillogram outputs of the driving pulse generated by the Op Amp based controller for the MOSFET switch for Duty ratio = 50%

MOSFET driver circuit

Fig5.6 (c) Duty cycle = 50%, Fig5.6 (d) Duty cycle = 66.66%,speed = 1262 rpm,

speed = 1320 rpm,

Gate pulse at MOSFET gate terminal for different Duty Cycle (Switching frequency at,

Duty Ratio fsw(KHz)

Rotor rectified Ripple

Voltage

VdcIdc(A)

Speed(rpm)

0.1869

4.6729 19.625 71.2 0.325 1104

3.33 21.5 70.5 0.33 1118

2.4272 25.875 69.4 0.34 1176

0.514

4.6729 29.75 46.4 0.33 1224

3.33 33.75 44.5 0.34 1246

2.4272 38.875 43.5 0.32 1255

Rotor rectified Ripple Voltage variation with MOSFET switching frequency at different Duty ratio.

Rotor speed variation with MOSFET switching frequency at different Duty ratio

Ripple in rotor rectified voltage against rotor speed at different frequency at D= 0.1869 & D= 0.514

D= 0.1869 D= 0.514

Rotor chopper current (Idc) against rotor speed at different frequency at D= 0.1869 & D= 0.514

MOSFET driver circuit and pulse width modulated gate pulse circuit

Experimental set up

Conclusion

The effect of chopper frequency at different duty cycles of WRIM drive with a resistive loaded chopper performance is studied.

The result shows that a low value of chopper frequency may cause fluctuation in motor speed and torque pulsation.

Increasing the chopper frequency, decrease the ripple in rotor rectified voltage, speed variation and improvement in the electromagnetic torque characteristics of WRIM drive with a resistive loaded rotor chopper is studied.

Scope of Future WorkThis thesis has successfully established the potential of wound rotor induction motor as a variable speed drive. Some aspects can be explored further to effect improvements in performance. A few of these are: The closed loop control scheme of wound rotor induction motor drive with resistively loaded chopper can further be designed, developed using Matlab/Simulink toolbox and developed the hard ware of this closed loop control scheme.

This control scheme has a disadvantage of low efficiency. In order to increase the motor efficiency while controlling the speed of the motor, slip energy recovery scheme can be developed with help of this thesis.

REFERENCES------------------------------------------------------------------------------------------------------------[1] M. G. Say, “Performance and Design of A.C. Machines”, ELBS and PITMAN,[2] Bimal K. Bose, “Adjustable Speed AC Drive System”, IEEE Press, 1981.[3] Muhammad H. Rashid, “Power Electronics: Handbook”, Academy Press, 2001.[4] L. Umanand, “Power Electronics, essential & application”, [5] Mohan Ned, Undeland Tore M. and Robbins William P.[6] "Power Electronics, Converters Applications and Design", John Wiley & Sons, Inc., Book, 1995.[7] Operational Amplifiers and Linear Integrated Circuits by Robert F. Coughlin, Frederick F. Driscoll[8] Steady State Modeling and Performance Analysis of Static Slip Energy Recovery Controlled Slip Ring Induction Motor Drive by B. K. Singh and K. B. Naik[9] Study on rotor IGBT chopper control for Induction motor by SHEN Tian-fei and Bo-shi, GONG You min ,School of Electromechanical Engineering and Automatic shanghai University, Shanghi 200072,china[10] Analysis and simulation of static Kramer drive under steady-state conditions B.A.T. AI Zahawi, BSc, PhD B.L. Jones, BSc(Eng), PhD, CEng, MlEE ,W. Drury, BSc, PhD, CEng, MlEE[11] INDUCTION MOTOR THEORY by Jerry Bednarczyk, PE[12] Bipolar transistors for MOSFET gate driving applications by Peter Blair, Product Development Manager[13] Power MOSFET Gate Driver Circuits using High Current Super-b Transistors 6A Pulse Rated SOT23 Transistors for High Frequency MOSFET Interfacing by Neil Chadderton Application Note 18 Issue 1 March 1996[14] APPLICATION NOTE, AN524/0994 DRIVE CIRCUITS FOR POWER MOSFETs AND IGBTs by B. Maurice, L. Wuidart[15] Matching MOSFET Drivers to MOSFETs Author: Jamie Dunn Microchip Technology Inc.[16] Design and Application Guide for High Speed MOSFET Gate Drive Circuits by Laszlo Balogh[17] IEEE Standard Test Procedure for Polyphase Induction Motors and Generators

Thank you all