solar grid tie / wind grid tie...different?

[makenzie71]

What are the operational differences between an inverter labeled for solar and one labeled for a wind turbine?

[DamonHD]

The solar one will be expecting DC with a max voltage and a particular V/I curve with MPPT set up for it, and will be happy to 'let go' of excess energy that it can't use since doing so is safe.

The wind one will expect wild AC with possibly much peak voltage transients, and will need something to happen sensibly with unusable 'excess' energy, such as clipping or dumping.

Or am I getting the wrong end of this stick?

Rgds

Damon

[makenzie71]

I guess I'm assuming everyone is rectifying and regulating before the inverter.  If the ones labeled for wind are taking in the raw three phase and doing all the xtra work that explains why they're labeled differently (and generally more expensive).

[DamonHD]

I've only bought and concentrated on the details of the wiring up of kWh-scale solar stuff, so I may simply be wrong.

Rgds

Damon

[makenzie71]

No i think you're right.  I've been looking at product pages and almost all the ones labeled for wind turbines are looking for three phase input and they control load diversion.

I think if you're charging batteries and are handling the dump and rectifying/regulating then it doesn't matter.  Volts dc coming in should be volts dc coming in, no matter the source.

(Of course, I could be wrong )

[SparWeb]

There are enough differences between wind and solar, so a system design is important, not just a choice of inverter.

I always feel bad doing this but to nitpick on some stuff, a "controller" is used to regulate a wind turbine output, and an "inverter" delivers AC from a DC source.  Some Solar Inverters can go without batteries, and connect between solar panels and grid and handle all the stuff that's happens there.  Not so common to do that with wind - usually you use a controller and a set of batteries.  Bigger scale stuff doesn't need the batteries, but then it's a grid-tie at a commercial scale, and the turbine has to support doing that just like the inverter.

A charge controller that can handle a wind turbine can, as Damon said, absorb transients on the power supply, and it's designed to keep the load on at all times.  If it's a MPPT wind controller, then it goes between the turbine and the batteries, managing the turbine operation.  If it's not a MPPT, then the charge controller just manages a diversion load so that the batteries don't over-charge.  This stuff doesn't matter in solar, so an inverter designed for solar is much simpler.  As you noticed, there's also a possible 3-phase supply or a DC supply in wind, and solar is always just DC.  That said, the solar grid-tie inverters can have a lot of features that the wind controller can't.

Best way to learn about it (IMO) is to keep reading those installation and operation manuals.

[makenzie71]

I always feel bad doing this but to nitpick on some stuff

Nitpicking is fine...half the work in researching stuff is trying to find out exactly what things are called, which things need to be researched, and weeding out the assumptions.

Like my assumption that everyone uses a "charge controller" off the turbine before they do anything else anyway

Everything I'm reading suggests that a wind turbine can be connected to a solar inverter so long as the voltages are in the appropriate range and your regulating/rectifying (R/R) and diversion load happens prior to the inverter.  The only advantage I'm really seeing in do it is the expense of the inverter, but it looks like that cost savings can be eaten up pretty quickly with the expense of a good R/R and setting up diversion.  The only reason I can really see to do it this way is if you were already setup to charge batteries but have, for one reason or another, decided to grid tie instead.

As I'm already regulating/rectifying, though not necessarily in that order, right after the turbine I may go this route if I can find an inexpensive means to handle diversion loads.

[makenzie71]

Why is diversion loading only a wind turbine concern?

[DamonHD]

Is is generally totally safe to just not use any 'excess' solar PV input.  The inverter/controller can just disconnect/ignore the input with impunity.

Do that with a wind turbine and the turbine can run away in high winds and destroy itself (and/or produce high-enough AC voltages to toast the inverter/controller too).

Rgds

Damon

[SparWeb]

Yes - just to add to what Damon said, the wind turbine needs to have an electrical load on its generator at all times.  If you unplug the generator, then the wind power put into the blades make them speed up, with nothing to slow them down (until they break). 

If you unplug a PV panel, nothing really happens.  That's the big difference.