Hi all,
I've got a situation where I need to limit the rate of change in current that is presented from a bank of solar panels to the inverter's MPPT front end, basically the cloud effect is now causing over current issues as the MPPT doesn't act quick enough to clamp the over current when the panels cop a full burst of sun after a prolonged cloudy period.
Based on some rough calcs, I am dealing with a change of approx 5A to 26A @ 300V, the MPPT front end only likes to deal with a max of 13A so you can see why it's burnt out when it can't respond quick enough (by changing the impedance presented to the panels to drive the MPPT voltage up higher, reducing the current and eventually limiting the power extracted from the panels).
The most simple and elegant solution I can think of at this stage is to install a large inductor in series with the panels, effectively acting as a damper during these "cloud bursts", protecting the MPPT until it can respond to the sudden change.
My question is now, how would one size an inductor to perform this task? I'd guess I need to go from 10-20ms 21A change and stretch it out to 100-200ms as a very rough starting point.
Any help or alternative suggestions would be greatly appreciated.
Cheers izy
I've got a situation where I need to limit the rate of change in current that is presented from a bank of solar panels to the inverter's MPPT front end, basically the cloud effect is now causing over current issues as the MPPT doesn't act quick enough to clamp the over current when the panels cop a full burst of sun after a prolonged cloudy period.
Based on some rough calcs, I am dealing with a change of approx 5A to 26A @ 300V, the MPPT front end only likes to deal with a max of 13A so you can see why it's burnt out when it can't respond quick enough (by changing the impedance presented to the panels to drive the MPPT voltage up higher, reducing the current and eventually limiting the power extracted from the panels).
The most simple and elegant solution I can think of at this stage is to install a large inductor in series with the panels, effectively acting as a damper during these "cloud bursts", protecting the MPPT until it can respond to the sudden change.
My question is now, how would one size an inductor to perform this task? I'd guess I need to go from 10-20ms 21A change and stretch it out to 100-200ms as a very rough starting point.
Any help or alternative suggestions would be greatly appreciated.
Cheers izy