Designning H Bridge for 200A

Thread Starter

artmaster547

Joined Jan 6, 2016
409
Hi All
I wondered if anyone could give any recommendations for pcb layout I am trying to design a H Bridge that takes in AC voltage and output 12VDC but at 200A, and I am constrained to a 4 layer 2oz Copper PCB but I do have access to the use of bus bars on the PCB, and I am using TO 220 packaged FETs does anybody have any recommendations for techniques I could use to get 200A through these Devices on a PCB, would appreciated any recommendations?

Kind Regards
Art
 

Thread Starter

artmaster547

Joined Jan 6, 2016
409

ArakelTheDragon

Joined Nov 18, 2016
1,350
Thanks for pointing that out it is much appreciated, unfortunately it is a design I need to complete, however I do have the option of using bus bars external to the PCB, my main concern is how to package it all though into one unit which is why I was seeking assistance here
Your requirements are very strict. Your best option is 1 diode right to the transformer and the load next to it to. If you can avoid a PCB it would be better.
 

jpanhalt

Joined Jan 18, 2008
10,064
Of the two high current controllers I have made, one had the mosfets soldered directly to bus bars made from 0.025 copper sheet:
upload_2018-11-9_7-29-52.png
The second of somewhat lower current needs had the mosfets soldered to 4 oz pcb mounted to the heat sink:
upload_2018-11-9_7-31-57.png

The heat sink formed one side of a vented box. Logic was also in that box.
 

DickCappels

Joined Aug 21, 2008
6,531
There are some circuits that are not suitable for implementation on a PCB. This may be one of them.

When I made a 45 amp water heater controller I used very large traces with AWG 12 wire soldered on top, similar to using a bus bar, but went on flying leads to the heat sunk triac right after that. That way most of the current path was off the PCB and the heatsink could be mounted high off the board to facilitate convective cooling.
 

DNA Robotics

Joined Jun 13, 2014
571
Assuming you are using multiple MOSFETs in parallel and will need a heat sink that will be attached to the tabs of each group, the tabs are the drain. You can bolt your 200 amp cables to the heat sink on each group. Now you can cut the #2 drain pin off the TO 220 MOSFETs making it a 2 pin component with 0.2" pin spacing. Then you have room for a MUCH larger pad and trace on your PC board for the source pin.

I did that on this board. The 2 pin components on the left with wide traces are MOSFETs.

MOSFETs on board.jpg
 

MisterBill2

Joined Jan 23, 2018
6,664
Several years ago I had to complete a project that was to deliver a total of 100 amps for almost a minute. The challenge was that it was to be small, self contained including the batteries, tightly regulated, and 100% reliable because it was going to ride in a crash car and film the airbag deployment. The design, which I inherited, along with the circuit boards, fully stuffed, worked fine on paper.
The failure was that everything has voltage drops at 100 amps.
So I am offering this fact so that you can avoid the same problem. Every connector has a voltage drop! Every wire has a voltage drop! And none of those drops show up in simulations.
Good luck on the project, you certainly will need it.
 

Thread Starter

artmaster547

Joined Jan 6, 2016
409
Great thank you all for the assistance it has been of great help :) I think I have ideas of what I can do from all your responses.

Kind Regards

Art
 
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