Pe dual converter ppt

Power Electronics
Dual Converter
GTU ALA PPT

1. Prepared By:- Rohan Kaushik (161310109051) Rohit Chavda (161310109052) Dual Conveters

2. CONTENTS Introduction Block Diagram Principle of operation Mode of operation Four quadrant operation Ideal Dual Converter Types of Dual converter Applications of dual converter

3. INTRODUCTION It is an electronic converter or circuit which comprises of two converters. One will perform as rectifier and the other will perform as inverter. Therefore, we can say that double processes will occur at a moment. Here, two full converters are arranged in anti-parallel pattern and linked to the same dc load.

4. BLOCK DIAGRAM Basic Block Diagram

5. Principle Of Operation A.C input given to converter 1 for rectification. In this process positive cycle of input is given to first set of forward biased thyristors which gives a rectified D.C on positive cycle, as well negative cycle is given to set of reverse biased thyristors which gives a D.C on negative cycle completing full wave rectified output can be given to load.

6. Modes of Operation of Dual Converter There are two functional modes: Non-circulating current mode. Circulating mode.

7. Non Circulating Current Mode One converter will perform at a time. So there is no circulating current between the converters. During the converter 1 operation, firing angle (α 1 ) will be 0<α 1 < 90 o ; V dc and I dc are positive. During the converter 2 operation, firing angle (α 2 ) will be 0<α 2 < 90 o ; V dc and I dc are negative.

8. Circulating Current Mode Two converters will be in the ON condition at the same time. So circulating current is present. The firing angles are adjusted such that firing angle of converter 1 (α 1 ) + firing angle of converter 2 (α 2 ) = 180 o . Converter 1 performs as a controlled rectifier when firing angle be 0<α 1 < 90 o and Converter 2 performs as an inverter when the firing angle be 90 o <α 2 < 180 o . In this condition, V dc and I dc are positive.

9. FOUR QUADRANT OPERATION

10. Ideal Dual Converter The term ‘ideal’ refers to the ripple free output voltage. For the purpose of unidirectional flow of DC current, two diodes (D 1 and D 2 ) are incorporated between the converters. However, the direction of current can be in any way. The average output voltage of the converter 1 is V 01 and converter 2 is V 02 . To make the output voltage of the two converters in same polarity and magnitude, the firing angles of the thyristors have to be controlled.

11. Block Diagram for ideal dual converter

12. Average output voltage of Single-phase converter = Average output voltage of Three-phase converter = For converter 1, the average output voltage, For converter 2, the average output voltage, Output voltage,

13. Types of Dual Converters They are of two types: Single-phase dual converter. Three-phase dual converter.

14. Single Phase Dual Converter

15. Three Phase Dual Converter

16. Application of Dual Converter Direction and Speed control of DC motors. Applicable wherever the reversible DC is required. Industrial variable speed DC drives.