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Seminar OnSeminar OnPhase Controlled Converters

and it’s applications In D.C. drives

Presented By Debraj Rakshit M.Tech (Power Electronics & Drives) Jalpaiguri Govt Engg. College

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What is Rectifier?• Definition:-Converting a.c.(from

mains or other a.c. sources) to d.c. power by

power diodes or by controlling the firing angle of thyristors/controllable switches.

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Types of Types of rectifiersrectifiers

• Uncontrolled Rectifiers

• Semi controlled Rectifiers

• Controlled Rectifiers

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Uncontrolled Rectifiers with R-load

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Uncontrolled rectifier with R-L-load

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Controlled half wave with R-load

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Uncontrolled full wave rectifier with R-load

• Bridge Configuration • Center Tapped Configuration• For both Configuration

• Vo ={VmSin ωt 0 ≤ ω t ≤ π

={-VmSin ωt π ≤ ω t ≤ 2 π

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Bridge Rectifier with R-Load

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Bridge Rectifier with R-L-load

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Vector Diagram of three phase supply voltage

V A N

V C N

V B N

1 2 00

1 2 00

1 2 00

RN AN

YN BN

BN CN

v v

v v

v v

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Three phase half wave converter with R-L load

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Necessary waveforms for three phase half wave

circuit

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Output voltage for various triggering angle

0

0

3 00

3 00

6 00

6 00

9 00

9 00

1 2 00

1 2 00

1 5 00

1 5 00

1 8 00

1 8 00

2 1 00

2 1 00

2 4 00

2 4 00

2 7 00

2 7 00

3 0 00

3 0 00

3 3 00

3 3 00

3 6 00

3 6 00

3 9 00

3 9 00

4 2 00

4 2 00

V an

V 0

V 0

V an

= 300

= 600

V bn

V bn

V cn

V cn

t

t

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Three phase full converter with R-L-load

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Waveforms for three phase full converter

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An Introduction to d.c. drives

• Definition:-An electric drive can be defined as an electromechanical device for converting electrical energy into mechanical energy for various kinds of process control.

• Classification of Drives:-• Group Electric Drive• Individual Electric Drive• Multimotor Electric Drive

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An Introduction to Closed Loop Control Of D.C.

drives• Closed loop System-Closed loop system

utilizes feedback to measure the actual system operating parameter being controlled such as temp,pressure etc.

• Open loop system-In Open loop control no feedback loop is employed and system

variations which cause the output to deviate from the desired value are not detected or corrected.

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Basic Block diagram of a closed loop speed control

system

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Essential parts of d.c. motor

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An introduction to closed loop control of separately excited d.c. motor

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Possible methods of speed control

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Introduction to dynamic equations and small

signal model of motor

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Small signal model of separately excited d.c.

motor

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Speed Control Loop

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Current Control Loop

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Proportional control to step change in speed

reference

Speed Response

Current Response

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Response of PI Control To Step Change in Speed

Reference

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Effect of Load Torque Disturbance

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Response to Step increasing load torque in

proportional control

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Response to step increase in load torque

with PI Control

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Linearized Model of dc series motor

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PLL based motor speed control

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Future Analysis Power Circuit of proposed QRZCS DC Drive

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Thank YouReferences

Power Electronics (M.H.Rashid)

Power Electronics (Khanchandani & Singh)

Thyristor Based DC Drive By P.C. Sen http://ieeexplore.ieee.org www.books.google.com www.en.wikipedia.org