Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Does this IGBT bridge meaningless ?

Status
Not open for further replies.

Hasan2017

Member level 3
Joined
Oct 23, 2017
Messages
64
Helped
0
Reputation
0
Reaction score
0
Trophy points
6
Activity points
718
Hello My Dear Friends!

Hope this post finds you well.

I am trying to develop a AC to DC rectifier 110V/50 A range.
Feeling that I am doing wrong on making the full bridge or half bridge portion.
The IGBT module I am using is FF75R12RT4,https://www.infineon.com/dgdl/Infineon-FF75R12RT4-DS-v02_01-EN.pdf?fileId=db3a304327b89750012805fd8fd76151
IGBT.PNG

One module contains 2 IGBT that makes me confusing!
I need to understand my switching topologies first

Take a look my diagram, how the current flows back from primary winding of TR for a full cycle?

igbt_bridge.PNG

1. When point A is positive then Q2 conducts, Q1 is OFF?
2. When point A is negative then Q1 conducts Q2 is OFF?
3. When point B is positive then Q4 conducts, Q3 is OFF?
4. When point B is negative then Q3 conducts Q4 is OFF?

Freewheeling built on doides are available, whats 2uF high voltage is doing here?
 

FvM

Super Moderator
Staff member
Joined
Jan 22, 2008
Messages
48,944
Helped
14,340
Reputation
28,944
Reaction score
13,084
Trophy points
1,393
Location
Bochum, Germany
Activity points
282,382
It's a regular full bridge, sketched in a rather nondescriptive way. 2uF are DC bus bypass capacitors, strongly suggested to avoid IGBT overvoltage caused by large di/dt.

1. When point A is positive then Q2 conducts, Q1 is OFF?
2. When point A is negative then Q1 conducts Q2 is OFF?
3. When point B is positive then Q4 conducts, Q3 is OFF?
4. When point B is negative then Q3 conducts Q4 is OFF?
A is DC+, B is DC- bus node. They don't change polarity. Confusion is apparently caused by the inappropriate schematic style.
 

Hasan2017

Member level 3
Joined
Oct 23, 2017
Messages
64
Helped
0
Reputation
0
Reaction score
0
Trophy points
6
Activity points
718
It's a regular full bridge, sketched in a rather nondescriptive way. 2uF are DC bus bypass capacitors, strongly suggested to avoid IGBT overvoltage caused by large di/dt.


A is DC+, B is DC- bus node. They don't change polarity. Confusion is apparently caused by the inappropriate schematic style.

Question arises if both node remains constant on polarity then why 4 igbts are used? One leg of primary TR connected with a pair of IGBT doesn't tell us that its polarity could interchange? Don't you mean the circuit is not wrong?
 

KlausST

Super Moderator
Staff member
Joined
Apr 17, 2014
Messages
20,547
Helped
4,463
Reputation
8,935
Reaction score
4,497
Trophy points
1,393
Activity points
135,829
Hi,

the circuit seems to be correct.
Node A is always positive, node B is always negative.

A "full bridge" needs 4 IGBTs. It has two ouputs. The difference voltage of both these outputs may be positive or negative.

Klaus
 

Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top