DIY Arduino controlled limiter for non limiting grid tie inverter

[brandonoh777]

I am trying to DIY build my own limiter for a non limiting 1000W grig tir inverter the best idea i have is to limit the DC input much the same was as lower sunlight limits the AC output. So i think this can be done with a circuit consisting of a mosfet (maybe some capacitors to smooth the output) and a Arduino to generate and very the PWM signal to the mosfet. Problem is a mosfet data sheet is intimidating to someone whos neevr seen one!!! ME! lol Can anyone help with the mosfet specs and maybe also cap specs i might want to try...?

inverter-- 24V 1000W so input voltages can range between about low 20's and about 37 (OCV of my panels) its a max 1000W inverter so at those voltages im looking at about 41 amps--prob not much higher than 45 amps and can i drive it with a 5V signal form the Arduino or will i need a separate mosfet driver? thanks!!

Brandon

 

[svetz]

There's a similar thought in the AC battery thread, what's your use-case for this? The PWM approach had a problem for that application, see this post.

Here's a link that explains mosfet datasheet basics, but I'd recommend investing $20 in a few small ones to play around with first.

Also, I'll move this thread to the Home Brew Solar Electronics forum where hopefully more will see it.

 

[rin67630]

1) PWM chopping the input of the grid tie inverter might not be much appreciated by the inverter electronics running their own PWM cycle:
You risk heavy interferences. Personally i never will risk that.
2) Driving a MOS-FET at 45Amps will require a strong gate driver, else you will have too long switching times and dissipate too much energy at linear intermediary levels.

 

[jdevine82]

I did this for a bit. I used igbt switching at 12k with a drive of 12v. Real simple Arduino voltage comparator. I got a heap of Rf interference, however the grid tie inverter seemed fine with it. I kept getting shorted igbts from lightning and other random things. Probably need better dv/DT protection. I am now going to attempt to add frequency shifting to my eg8010 based in inverter and just put a relay on ac side of inverter operated by my BMS