Combiner box with MPPT system

[Jimbo]

Hello fellows,

I`m the new forum member and I`m a newbie in PV technology.

The question is if there is combiner box equipment on the marked which is equipped with MPPT system and do I need such equipment in my project?

Solar plant without any obstacles and building shadings. modules of the same orientation.

Solar array consists of 22 modules connected in series.
Arrays (12-20 pieces) are connected in parallel to combiner box via string monitor.
Combiner boxes(CB) are plugged in the DC input of Inverter Station (~600 kW).

I`ve read a lot of articles about the MPPT systems and it now seems to me that inverter with multy-MPPT is not enough for this system because I will have a lot of yield losses on CB. Modules cover the huge area and clouds will shade different parts of modules connected to one box.
If I understand right the inverter MPPT extracts the maximum power from CB boxes. I mean multi-MPPT system will find the appropriate rate for all CB.
But to extract the highest yields from solar modules we need CB with multi-MPPT. Do we?
P.S. I d`ont consider power boosters for exact modules because i think its not applicable

Thank you for answer. I feel that the question is stupid but cant handle it myself.

[Mike90250]

A solar array of 22 modules in series: (I assume modules = 200W PV panel)

1) is not HUGE
2) if they are all in series string, would not need a Combiner Box, as CB is used for parallel strings ( 2 strings of 11 panels)
3) 22, 12V (23V Open Ckt panels in series = 506V, a bit toward the high side for many inverters), you should run your array through your inverters sizer chart, and make sure in cold weather, you don't exceed the max volt input.
4) cloud cover over a 22 panel array will shut off the entire array while more than 2 panels are shaded. Trying to minimize this is pointless, either the whole array will be covered or uncovered within seconds.

I'd suggest you list your parts and plans for us here, to review, before you spend any more $$. we really try to help for free, and make sure you have a good solar experience.
(unlike my array that's been shaded for a week now, and someone fueled the 2 gensets with 2 cycle premix)

[Jimbo]

Mike,
thank you very much for your answer. But it seems like some misunderstanding.

I`ve said that there are 22 modules in 1 array connected in series. Something like 8 to 10 arrays are paralleled through combiner box (CB) and then connected to inverters input. There are for example 6-8 CB`s.
In this situation what is the best way of gaining the highest yields using MPPT?
It seems for me,that in this case inverter`s multi-MPPT will not be effective as it should adjust the load for the whole PV modules and whole CB`s on its input.
I wonder if it will more profitable to use CB`s with their own multi-MPPT?
So that every CB could provide the load to the arrays connected to its input?
I`ve found such equipment in web: SATCON SOLSTICE SSB.

I have also one technical question. If we have for example 3 strings with their own MPPT systems and then own I-V curves( I1≠I2≠I3, V1≠V2≠V3) and we align them in parallel to one string how their parameters being summarized? For example inverter has N inputs which are then aligned.

I hope to have the answer. So thank you in advance.

[Mike90250]

OK, so you are not working with a household inverter, but a large, 3 phase commercial rig?

Anyway, combiner boxes are simple connection boxes with fuses/ckt breakers, like a sub panel.

Solar PV arrays IN THE SAME ORIENTATION can be easily paralleled and fed into a single MPPT . No problem.

If some of the array is shaded, or faces a different angle, that will confuse the MPPT, and that's when you get rid of the shade. Arrays with different angle, each angle needs it's own MPPT. Again, clouds don't count, until you cover larger than an acre. But that's too large for a single inverter anyway.

How do you know the inverter has multiple MPPT channels ? Most inverters only have 1 MPPT.

IF you MIX brands / technologies of PV, you will need a separate MPPT channel for each different one. (thin film. polycrystalline, monocrystalline), they have slightly different MPPT curves.

But, all combiner boxes I've seen, are simple sub panel, there are no MPPT electronics in them. Maybe large scale utility systems have that, but that's not in my price range. Your own Engineer (if you are doing multi-kilowatt production, you NEED your own engineer) should be on top of this, along with the utility and transmission line planners.

Mike

[russ]

I'm with Mike - With something like 200 panels and say 200 watt panels that is a 40 kW system.

It needs to be designed by an engineering company that knows solar. This is not in the DIY range. Your utility will have all sorts or requirements that the electrical engineer will have to deal with.

If not it could get expensive real fast.

Russ

[Jimbo]

thank you, guys