Solar Grid Tied Inverter Vs Wind Turbine Grid Tied Inverter

mnittler

Assumptions:

1. The Wind Turbine 3 phase AC voltage has been successfully converted to DC voltage.

2. The Wind Turbine AC to DC Full Bridge rectifier converter circuit is producing the correct DC voltage range for the solar Inverter specs.

3. A Wind Turbine protection box has been built and installed to dump any wind turbine watts generated to a dump load during Grid loss.

4. The Wind Turbine DC voltage varies quicker than the DC voltage from a solar cell string.

5. The Wind Turbine has the possibility of exceeding the watt rating of the solar inverter much like installed solar strings exceed the watt rating of the solar inverter rating.

6. Inverter Efficiency is not a consideration

7. Grid Tied Inverter is used.

Is there any reason that a Solar Grid Tied Inverter with the same DC input voltage range as a wind turbine DC output Voltage range would not work using a wind turbine as the DC voltage source?

mike95490

Yes, there IS a reason not to.  It would be likely to work poorly.

Solar GT inverters are designed to work with a solar panels power curve.  A wind turbine has a DIFFERENT CURVE, and the controller will not be able to regulate itself well, say the inverter temp goes high, the normal response is to degrade the PV performance by changing the voltage point till the inverter cools down.   But wind turds have a different curve and the the controller may fault or fail completely.

bill von novak

mnittler said:

Is there any reason that a Solar Grid Tied Inverter with the same DC input voltage range as a wind turbine DC output Voltage range would not work using a wind turbine as the DC voltage source?

Yep.  They're not designed for the power curve of a turbine, and turbines have additional requirements as well (like dump loads and brakes.)  Midnite Solar has a charge controller with a wind turbine setting that can support them.

mnittler

Are there any Solar inverters that allow you to change the power curves?

mike95490

mnittler said:

Are there any Solar inverters that allow you to change the power curves?

I doubt it.  solar PV has one curve.   Wind Turbines could have several curves. Water turbines - several curves.

clockmanfran

 I trust that I do not upset any one here.

Yes, power curves for a Wind Turbine can be set/changed, but as far as I am aware only using a Midnite classic controllers.

If i recall 'Kitestrings'  has several Midnites connected up to his wind turbine.

Here they are working.......https://www.fieldlines.com/index.php/topic,149124.0.html   .... do a search on that forum to see how 'Kitestrings' set the controllers up.

It was a lot of work and not for the faint hearted.

He is charging batteries, but I see no reason, with a lot of thought, a GTI could used as a AC coupling device. 

SMA did the 'Windy Boy' which was dedicated to smallish wind turbines as a GTI. Old used 'Windy Boys' are always an option.

Its the furling control of the wind turbine that is Very Important, so a relative constant output is maintained. 

 NB, constant is the word here, even my three 12 footers/3.7m dia, scare me sometimes in ferocious storms when the voltage climbs so rapidly for a brief instance, and I grab my 'gentleman parts' ......    tum tee tum!        

mnittler

The SMA Windy Boy was a fine inverter.  SMA has not made them for quite a long time now,

From what I understand the Windy Boy started out as a Sunny Boy.

I had looked at the control scheme on a Windy Boy and they seem to only have 3 points on the voltage to power curve of the inverter. 

So that looks like the voltage to power curve must be pretty linear. The SMA Windy Boy has the following user defined parameters that pretain to Wind and probably Solar also.:

cut-in voltage setting

Max invert watts (I am not sure this one was a variable or not but it is on the parameter list).

And these 3 voltage to power curve settings can be changed.

Low Volts = 0% of inverter rated output (Above cut-in volts)

Mid Volts = 50% of inverter rated output

High Volts = 100% of inverter rated output

(The voltages and % of inverter rated output of these 3 power curve parameters can be set)

Do any of the Grid tied solar inverters have power curve settings that can be user defined?

The MidNight Solar is an excellent charge controller and it does have a wind setting but I am looking for a Grid Tied Inverter that will work in the maximum 480vdc input range. I could if necessary drop the voltage with a step down transformer (like a 460vac to 240vac ttansformer installed before the rectifier but at additional expense)  but then the amps would also go up but the watts would remain nearly equal except for the transformer loses.

clockmanfran

At 480vdc your in the right voltage range.

As far as I am aware, I do not know any GTI where you can adjust the power curve easily.

I do have SMA Grid guard codes and when I have reset SMA GTI's (the old toroid types), for fast sequential shut down and start ups, and voltage settings  on a AC coupled Grid, I did not see any explicit info on Power curve settings.

If you don't get any more info here, then try that 'fieldlines' forum, I do recall seeing some correspondence about GTI power curves, and I feel sure some one on there has experimented. 

Sorry to the Mods here for mentioning another Forum.

BB.

No problem pointing to other forums.

We aim to get people to the best information and sources.

Bill

bill von novak

mnittler said:

Are there any Solar inverters that allow you to change the power curves?

Not really.  Keep in mind that most charge controllers don't have "power curves" in memory that they try to match.  (Bluesky is one exception.)  Most of them just sweep the voltage/current and then look at the resulting power.  Wherever it sees the most power - there it stays.  No need to "know" the curve.  (Which is a good things, since crystalline and amorphous panels have different curves, for example.)

There are lots of details on how it does that scan, though.  Some do a full scan.  Some start with a guess, then iterate up and down slightly to zero in on the maximum.  Most of them aren't adjustable in terms of how they do that - but I think Midnite Solar has some level of control over their method of peak power tracking.  They have solar, wind, hydro, "legacy P+O" and a few other modes.  They differ in how often they sweep, how "deep" the sweeps are and what they assume.  I believe they even have a way to input a "power curve" for wind turbines that comes close to what you mention above.