Adjustable 1000A current source? - Page 1
Forum section: electronics / testgear

author: nctnico
author_rank: Super Contributor
timestamp: November 19, 2014, 02:17:03 pm
content: For an upcoming project I may need to test the behaviour of Mosfets switching a lot of current. I don't need a lot of power (I don't want or need things to run hot) but I do need a lot of current. The 1000A is a rough number it could be less or more. I'm wondering if there is any affordable equipment out there that may help me achieve this?

author: Richard Crowley
author_rank: Super Contributor
timestamp: November 19, 2014, 02:23:38 pm
content: How exactly do you get "not a lot of power" at 1000 amps?Or, perhaps we should ask what is your definition of "not a lot of power"Can you put a number on the "power" or "voltage" or something here?

author: nctnico
author_rank: Super Contributor
timestamp: November 19, 2014, 02:36:40 pm
content: Not a lot of power: 100W max. otherwise I expect the Mosfets or PCB traces to burn up. So the voltage is around 100mV or so at 1000A. A few volts (say 5) of open voltage would be nice.

author: wraper
author_rank: Unknown
timestamp: November 19, 2014, 02:40:23 pm
content: How long it should be? If you need only for a short moment, huge capacitor bank might do the job.

author: hamdi.tn
author_rank: Frequent Contributor
timestamp: November 19, 2014, 03:06:30 pm
content: i think it can be done with low frequency transformer ,2000 turn primary and 1 turn secondary, 200V @0.5A for p , 0.1 V @1000A.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: November 19, 2014, 04:02:15 pm
content: If you're doing what I grossly guess you're doing, it's normally done by pulsing an inductor with the DUT, then switching off, on and off to obtain the switching data at the requisite current level.'Cuz after all, if you only need a "constant" current for a microsecond... an inductor of sufficient size is exactly that.Tim

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: November 19, 2014, 04:22:20 pm
content: Quote from: nctnico on November 19, 2014, 02:17:03 pmhttp://www.digikey.ca/product-search/en?pv724=1348&FV=fff40002%2Cfff8000c&k=supercap&mnonly=0&newproducts=0&ColumnSort=0&page=1&quantity=0&ptm=0&fid=0&pageSize=25Maybe? It's rated for 100A, maybe whack a few in parallel.

author: commongrounder
author_rank: Frequent Contributor
timestamp: November 19, 2014, 04:29:10 pm
content: Maybe you could find yourself a used, reasonably priced, spot welder. You could control the current somewhat with a suitable variac on the AC input. This is assuming an AC current source is acceptable. Just a thought.

author: nctnico
author_rank: Super Contributor
timestamp: November 19, 2014, 04:29:54 pm
content: I want to be able to test for longer periods (up to several hours). The test rig is supposed to simulate high currents for verifying circuits and testing short circuit protection behaviour. I need the current to be controllable so using capacitors or AC are out. The idea I have so far is to create a 4 phase synchronous DC-DC converter where each phase can deliver up to 250A.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: November 19, 2014, 04:37:21 pm
content: Quote from: nctnico on November 19, 2014, 04:29:54 pmGet in touch with folks who do NDT testing.http://www.dcm-tech.com/products/magnetic-particle-inspection/They aren't fooling around, but don't usually use what we'd call DC. But it's close.

author: krish2487
author_rank: Frequent Contributor
timestamp: November 19, 2014, 08:49:35 pm
content: Quote from: hamdi.tn onTodayat 02:06:30 AM

author: Marco
author_rank: Super Contributor
timestamp: November 19, 2014, 09:28:48 pm
content: Quote from: nctnico on November 19, 2014, 04:29:54 pmSo 4 forward converter current sources in parallel?Electroplating power supplies seem to have somewhat similar specs BTW :http://www.volteq.com/volteq-power-supply-hy051000ex-5v-1000a-over-voltage-over-current-protection-220v-input.html

author: nuno
author_rank: Frequent Contributor
timestamp: November 20, 2014, 12:08:27 am
content: if it were just for the switching behaviour, an appropriate "cap" on the input and a double pulse test (current controlled by the 1st pulse ON time). How long does it take for the FETs to switch? (are they switching many times a second or they're acting just as a power switch?)update: well, I guess I'm assuming you're driving inductive loads but may not be the case.