I want some directional advice regarding the pulsing from cap bank to battery bank.
50 ms pulse and 300ms delay for example. My ignorance is in the area of the best type of 50A rated mosfet to pulse with arduino and basic functional hookup.
I have been using an UNO and pulsing on a lower power level, but when I increased system power, I started to explode mosfets. It looks like I'll need several in parallel and a reliable pulsing approach. If one has experience with this I would appreciate advice. I have experience with arduino and mosfets but not at this power level.
Thanks,
brodonh
Welcome to the forum. Did you skip past the forum introductory guidelines?
You need to post a lot more information.
Be sure You know what the current will be. Then get MOSFETs rated for that current. Which MOSFET did You use?
Create schematics, pen and paper usually works well.
It is possible to connect MOSFETs in parallel but, they should be of the same type, manufacturer and date code, so their properties are very well matched. The input capacitance will of course be cumulative, harder to switch on and off.
Posting an annotated schematic would help. Your MOSFETs should be rated more voltage then your load voltage. I would not consider anything less than 100V. MOSFETs explode when overloaded the get hot real fast and go boom. That is caused a lot by not properly driving them. Look at the data sheet and look at the curves, they will tell you how much voltage you need on the gate to switch a given load. Paralleling them the best is to put them on the same heat sink. Even if they are mismatched they will share as the are PTC (Positive Temperature Coefficient) devices. The process is such as one starts overloading it gets warm, causing its resistance to rise, the others will follow suite. Here is an app note that will help: AN_2009_PL18_2010_105641 Here is another, they will not all agree. https://blog.csdn.net/liugaoxingliushi/article/details/127075676. You will need to use some care when doing this.
Also since you are pulsing them you need to take into account the rise and fall times when switching as when not in saturation it is getting hot. Siemens at one point in the 80 would say use silicone instead of heat sink. Hint be sure it is driven properly.
I think that you need a coil in between that flattens the current spikes. See switching power supply techniques.
So your duty cycle is 50ms/300ms = 16.7%.
The power dissipated by the MOSFET is I^2xRon.
If your MOSFET has an Ron of 10mOhms, the the power dissipated is 50^2x0.01 = 25W
However for a duty cycle of 16.7%, the average power would be 25W*0.167 = 4.175W
If you have a good heatsink and fan a single MOSFET should work, but that is not the problem.
Inductances in the MOSFET leads, and any wires you have connected will cause huge voltage spikes between the MOSFET drain and sourse that will exceed the Vds, thus destroying the MOSFET
You may want to consider an IGBT
Hi, @brodonh
Welcome to the forum.
Can we please have a circuit diagram?
An image of a hand drawn schematic will be fine, include ALL power supplies, component names and pin labels.
Can you please post a copy your code?
Thanks.. Tom...
Might be worth using a gate driver to make sure the MOSFET switches quickly:
Also, make sure you use a MOSFET that will be fully on for the gate drive voltage you are using, which, for 5V, means using a logic level MOSFET.
I recommend you play with 12V 1A for a while...
60 V can kill
60 V times 50 A = 3000 W. It is quite easy to weld things together or start a fire.
If you run this through a coil, you may get serious high voltage when you shut down the current.
Highly not recommended for someone asking the questions you are asking here.
Hi,
What is your actual load current?
What is the application of your project?
Tom...
That's where freewheel diodes enter the scene. Remember my suggestion to look at switching power supplies for approved circuits?
I know, but does OP know?
If he takes the chance to learn?
I attempted to upload a schematic but was told that newcomers cannot upload.
I have been on this forum before and received help to build a 60A relay, 24v, 4 battery bank swapping system. It works perfect.
I rejoined lately because my old email is no longer in use.
bro d
To post images etc you need trust level 1, you can get there by:
- Entering at least 5 topics
- Reading at least 30 posts
- Spend a total of 10 minutes reading posts
Users at trust level 1 can…
- Use all core Discourse functions; all new user restrictions are removed
- Send PMs
- Upload images and attachments
Really? A dropbox link is all you can provide, when you're given a way to post?
Dear Mr aarg,
I posted this afternoon that I was not allowed to upload because I'm in the category of new member and not trust level1.
bro d
Anyway, you can be permitted now, if you follow the actions in reply #16.