Good Three Phase Wind Turbine Grid-Tie inverter

[Can Alex]

Hey folks

I have a 10kW Bergey BWC that a customer wants to connect to 3 phase panel (industrial customer) Now, as you probably know, Bergey BWC Grid-Tie inverter is single phase output. I talked to Bergey and they say that I could just connect the single phase output to three phase power. This would throw off the phase loading on the distribution system of the customer and his plant manager is not to keen on that.
Now, alternator output of the turbine itself is 3 phase variable AC. Voltage can go up to 600V at really high speeds.
My only solution is if there is a manufacturer out there that makes customizable converters (inverters) which can be programmed so they are married to turbines variables that will maximize available output of the turbine and still make it a three phase output.
My understanding is it's not that easy to pick up a inverter off the shelf and install. There are different variables of the turbine that need to be programed into the converter for it to work properly.
Some turbine manufacturers recommend to use one converter per phase (SMA WindyBoy). Not too sure as this product is only rated to 6kW and it's only DC input.

Anyone had a run-in to this sort of scenario before?

Any help would be appreciated.


Thanks

[Rob Beckers]

Hi Can,

Not sure how much help this is, but here goes: Together with Mel we've been looking into replacing Bergey's GridTek inverter with one or more Power-One Aurora inverters (their largest is currently 6 kW, a 12 kW has been announced for later this year). Currently that would take two inverters, they can be stacked, and they can be programmed with the correct power curve for MPPT for the particular turbine. If you've looked at the WindyBoy, the Aurora is very much like the WindyBoy, though the Aurora uses many more entries than the two or three point MPPT table of the WindyBoy. We have a power curve that matches the GridTek, and voltage levels (even unloaded) seem to be well within the limits of the Aurora inverter. In short, short of testing it looks like this will work for single-phase (or rather, split-phase).

Now, the Power-One tech guys tell me that the same can also be done for three-phase output. However, it takes 3 inverters, and a 3-phase transformer to couple them (the inverters do not have galvanic separation internally, so to stack them it takes a transformer). There are two obvious downsides to this; it's expensive (3 inverters plus transformer!), and the transformer will continuously leak 100 - 200 Watt just to keep it magnetized.

In view of that, why not just feed back on one of the three phases? Most of the time the turbine will produce little, and even at 10kW it seems a very small load imbalance. The cost and effort to feed three-phase seems disproportionate. Of course, if it's worth it to your customer then by all means...

-RoB-

[Can Alex]

Thanks Rob.

I think explaining to the owner that his most cost effective option is to go with single phase output connected to three phase line.



Cheers


Alex

[Rocky Hill]

Hi Guys,

I have a Bergey Excel 10 KW with Gridtek inverter, System installed new in 2004.

The inverter freezes at various intervals shortly after cut-in. I can tell the inverter has failed because the RPMs do not change and the turbine spins without load. There is usually no error and the reset button does not work. The main power breaker has to be cycled to restart inverter.

I found a repair facility that estimates $2000 repair with really no idea what is wrong with unit, and requires me to ship whole unit. I am reluctant to invest this much in an unreliable (second repair, first was under warranty) inverter that tends to cut out in gusty conditions and is less efficient than the new Bergey inverter. I am also reluctant to invest $8000 in a new inverter for a turbine that has reached it's half life expectancy.

I'm 62 years old......do I have time to consume $8000 worth of electricity on top of the initial investment that has not yet been realized in power production?

I have serious doubts any Bergey Excel system has lasted long enough to pay for itself in a grid tie scenario. I hope I'm wrong. My turbine produces about $100/month
in electricity savings when it works.

You mentioned some alternative inverters.....are they cost effective?

I've had a very expensive lawn ornament loafing on my horizon for over a year that makes a lousy advertisement for wind power.


Rocky

[Power Waze]

Has anyone found another inverter that will work with the 10Kw Bergey?