This document summarizes a presentation on a three phase fully controlled rectifier. It introduces the topic, outlines the objectives to design and fabricate the rectifier and its control unit. It describes applications of three phase rectifiers such as DC motor speed control and battery charging. Block diagrams and circuit diagrams are shown to illustrate the design.

1. A Presentation On
“Three Phase Fully Controlled Rectifier”
By,
Keshar Rawal (32044)
Suman Shrestha (32048) 10 October 2012

2. Introduction
Objectives
Applications
Block Diagram
Work Done
Conclusion
OVERVIEW

3. INTRODUCTION
 Primary energy source are available as AC but many
application needed dc source.
 For high applications, three phase rectifiers are needed
 Variable DC can be obtained using thyristor.
 Microcontroller base thyristor schema is best because
of low loss, low cost and flexibility.

4. OBJECTIVES
 To design and fabricate three phase fully controlled
rectifier.
 Design microcontroller based control unit.
 To design bridge rectifier circuit. .

5. APPLICATIONS
 DC motor speed control in industrial application
 Base design for higher power application
 Home appliances
 DC motor drivers
 Battery charger
 Base for the AC-AC converter.

6. Block diagram

7. Bridge rectifier

8. Thyristor conduction schema
 The thyristor are trigged at interval of π/3
 The frequency of output ripple is 6*f
 T1 is triggered at ω*t=(π/6+α), T6 is already conducting when T1 is turned
ON.
 During the interval ( (π/6+α) to (π/2+ α) T1 and T6 conduct together and
output load is equal to Vab=Van-Vbn
 Each thyristor start conduct after 60 degree.
 Out put voltage varies according to that pulse given to gate
Vd= 3𝑉𝑚/𝜋 * cosα cosα =0 for α=90
cosα =1 for α=0

9. Programe flow chart

10. Circuit diagram

11. Zero Crossing Detector

12. Power Supply Unit

13. Output Of ZCD
 Waveform of crossing of two line voltage with respect of neutral

14.  Output waveform of microcontroller’s 1st output pin without delay

15.  Output of last pin without delay

16. Triggering pulse with maximum delay

17. Isolation circuit