I am doing a project in which I have to switch between two connecting configurations ; series and parallel, of solar panels. I want some suggestions for switching circuitry. Here are the options i have so far:
i) Use of relays but in relay there would be a large time delay so how can i cope it up? If you are suggesting me capacitor then please tell me how can i calculate the required capacitor ratings?
ii) Using transistors. If i want to implement it then i have to make compatibility between generated currents and base current ratings of transistors. To cope up with it i can use arduino in between that can generate the required signal to operate the transistor as a switch.
Please give me suggestions about it and a rough idea of circuitry.
relays always open before closing, so you have time when the arm is traveling from one contact to the other.
this is rarely a problem with mechanical things, but if you are powering an electronical device, you cannot have any interuption. to calculate the size of the capacitor, you have to know the load you need to deliver and the time it has to deliver that load.
a very detailed sketch would be needed. how can the load take two different voltages ? I would probably chose to use a battery, but there is that two voltage thing......
i) Use of relays but in relay there would be a large time delay so how can i cope it up?
Yes, a circuit diagram would be great. Regarding relays, you actually can get them with "make-before-break" contacts. This might be useful, but we need to see your circuit. MBB Contacts (G2A-4L32A)
EDIT: Well, scratch that idea ... this "general purpose relay" doesn't come with a general purpose price!
dlloyd:
Yes, a circuit diagram would be great. Regarding relays, you actually can get them with "make-before-break" contacts. This might be useful, but we need to see your circuit. MBB Contacts (G2A-4L32A)
EDIT: Well, scratch that idea ... this "general purpose relay" doesn't come with a general purpose price!
MBB are no general purpose. and as the parts become more rare, they go up in price to krazy numbers.
Robin2:
I think you need to explain your total project. It seems a strange requirement to change solar panels from series to parallel connection.
Why does it matter if the switching is slow?
Don't you have a battery connected to the panels that could provide continuity during a switch-over - if that is the problem?
You could mimic make-before-break with multiple simple relays - but it sounds like a recipe for a short circuit and smoke.
...R
I am guessing he will ride the curve so to speak
series in the overcast days and morning/evening with the Sun on the horizon. in series, the panels will deliver very low voltage per panel, but give you some extra time to charge with.
then, in the bright sun, each panel will be putting out maximum voltage and that would be too much for the charger.
alas, this is also probably not the case, because the actual interface would have access to the batteries and any electronical bits would more properly be powered from the batteries, not the raw and wildly changing voltages from the panels.
as for the relays, a simple super cap would hold the charge for the few ms that the contacts swapped from one to the other state. that part is not the hard part. that part is just sizing for the load.
I want to switch circuitry according to irradiance levels. So, i have to switch it minimum of 2 times on sunny day. The reason is i want to operate panels in parallel when light intensities (irradiances) are low and in series when high.
I have to say I still don't understand the need for switching speed. I swap one of my solar panels between two batteries by manually pulling off one plug and plugging on the other.
What circuit are you talking about that does not like transients?