High current pwm DC controller

Hello I have an idea to build an Arduino controlled pwm type dc controller to be used for a limiter on an unlimited grid-tie inverter... there are many projects out there showing how to do this but most of them deal with much lower currents than I will be dealing with I would like for it to be able to handle 1000 Watts easily the DC input will be around 24 to 30 volts so that's somewhere in the vicinity of 40 to 50 amps. You can buy pwm DC controllers that can handle approximately 40 amps my question is with a couple of arduinos some Electronics knowledge and the other properly size components could I build two of these cheaper than I could buy them? I get the basic math behind this but I also need some advice on sizing the components the mosfets capacitors and other components to handle this type of load...

Thanks brandon!!

Hello,

Be careful with those currents and powers, unless you really know what you are doing, to can start a fire.
From your question, I cannot deduce the level of expertise that you have in the matter.
DC and relatively high currents need to be handled with proper fusing care, cooling of power components etc.

There are components in the market that are state of the art and can be used for something like this: DC solid state relays are able to handle this, but know that flywheel diodes, fuses and other things might be essential to obtain a safe and reliable operation.

Best Regards,
John.

It should be pretty straightforward to build such a controller. Cheaper than buy? Not sure - especially when you take the fairly nice metal case into account that those things tend to come in.

All you need is MOSFETs that can handle the current and voltages involved (check RDS, ON ratings!), a PWM input, a PCB with sufficiently large traces and proper terminals for the input and output currents, and a handful of supporting components such as the PWM source (e.g. an Arduino or 555), pot or other method to set the actual duty cycle, gate drivers for the MOSFETs (pretty much mandatory in this kind of application), voltage regulator (buck converter) to power the logic, a fuse may come in handy, reverse voltage protection for the logic supply as well, that’s about it.

Consider placing two MOSFETs in parallel. Maybe even three. Makes handing the current and heat dissipation a lot easier.

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