ABB Aurora wind inverter

[Paul Pavone]

I have a 48 V off grid system I assembly in a 20 ft. shipping container. I am using a SMA sunny island and sunny boy for 6000W and a 1.5kW wind turbine I designed. The 220 Vac PMG is powering the Aurora WIB and the 3.6 wind inverter. I am having issues with an error on the gird freq. with the wind inverter. I was told that ABB has software to program the grid freq. to a variable setting. Is this true? or any solutions.

[Rob Beckers]

Hi Paul,

At the time that we were still a distributor for Power-One/ABB we were told there was no way to change the frequency; this was part of the firmware. It was not part of the factory menu inside the inverter either (I had access to that, those are the parameters an installer cannot normally change, each inverter has its own access code for that menu). It's been a year and a half since, so maybe this has changed.

For grid-tie inverters the requirements for frequency stability are very, very strict. It doesn't take much before the inverter is forced to disconnect (based on UL1741).

The Sunny Island inverter uses frequency shift to tell the other inverters (WindyBoy or SunnyBoy) when the batteries are getting full, to taper their output power. That throws off any regular grid-tie inverter. I've been told that you can switch this behavior off in the Sunny Island, but have no personal experience with that inverter. If you switch frequency shift off, you'll have to provide an alternate mechanism for charge control though (diversion controller for example).

-RoB-

[Paul Pavone]

Thanks Rob;
I am waiting on ABB to respond. My supplier said that ABB showed him how to do this. Maybe it is something new for off grid only.

I'll let you know.

Paul

[Rob Beckers]

Paul, please post back once you know how to do this. That is useful information for others (me included).

-RoB-

[Christopher Smith]

I'm on now. Thanks for the link.

[Cor van Houtum]

hello Paul
did you ever find out how the freq shift setting works
in combination with power one

[Paul Camilli]

Long time member but first post and I appreciate this is an old thread but I've just installed a 3.6kW Aurora on an 'off grid' 'AC coupled' system and I too would like to widen or disable the anti islanding parameters.

I've been running a grid tied Proven 2.5/3.2kW turbine for a few years now using an SMA WB6000 into a grid created by an SI6.OH. I disabled the FSPC (frequency shifting) long ago and rely on a combination of AC and DC dump loads driven by 4 Tri Stars. The system works brilliantly in combination with AC and DC coupled solar and hydro providing all the heat and power to our 120m square house.

However, I've never been totally happy with the SMA/Proven set up and it's inability to 'grid feed' below 230VDC. Consequently I recently installed the Aurora and three days ago finally managed to program a curve into the unit and try it out. Despite there being virtually no wind the inverter was happily feeding .3kWh a day into my system. This on days when the SMA would be doing 'diddly squat'. I was well pleased, but also know from previous experience with using GTI's that as soon as I switch on a heavy inductive load it'll 'drop out' unless I can widen or disable the 'anti islanding' parameters.

Is this possible?

Cheers, Paul

[Rob Beckers]

Hi Paul,

If you send me a Private Message with the serial number I'll return the factory-menu access code. That allows you to change the grid under- and over-Voltage limits, and there are some anti-islanding settings that I've never messed with, but feel free to try those (since you're not on the grid there's no risk of electrocuting lineman working on it).

-RoB-

[Paul Camilli]

Cheers Rob,

I just love this inverter, been using SMA's since 'Adam was a lad' and on the whole been really impressed with both the inverters and service but their software is pants and very 'user unfriendly'. Apart from that bug with the 'Aurora Installer' and gross CPU usage (which I sorted) I find this Power One a pure joy to tinker with.

I have a non standard 'air gap' in my turbine so the factory power curve is no use. I'm having great fun playing around with mine, it's just so easy to alter.

Cheers, Paul

[Rob Beckers]

Paul, I've sent you the access code. Hopefully it works!

These inverters actually come empty from the factory, there's no default MPPT curve as far as Power-One is concerned, must have been your supplier that put one in. They show "missing table" when fired up for the first time.

I agree that by and large they work very well. Biggest problem I saw is that any DC Voltage over 600 Volt will let out the magic smoke. There's no protection inside at all against that, and a whole lot of people had flaky wind turbines that didn't control output Voltage.

Anyway, hope you get it to do what you want!

-RoB-

[Paul Camilli]

Hi Rob,

sure enough, there was no curve in when I got it and I installed the one recommended by Proven/Kingspan (they fit the 3.6kW inverter on their 3.2kW turbines). However, my turbine has a much wider airgap than standard. Turbine is in a very good spot and was putting out 4.2kW at times!!!! That was using the SMA WB6000, sadly it burnt out the stator last winter so when I fitted a new one I increased the air gap by a couple of mm, consequently the power curve used by the turbine manufacturer wasn't much use, but a good starting point for experimentation, which I'm enjoying doing.

Cheers, Paul

[Rob Beckers]

Paul, it's possible to calculate an MPPT curve in case you have trouble adjusting things to where they work. Changing the air gap will affect the Voltage, so various power levels from the rotor will happen at different Voltages now.

Not sure if a wider air gap will provide any protection against burning it out. The way it works is that for a given wind speed the rotor will produce a given amount of power. That needs to be extracted by the alternator or the excess will go towards speeding up that rotor. So, for a stable wind speed and rotor RPM the power from the inverter matches that of the rotor (short of various losses along the way). Heat in the stator is a function of the stator current, and power is a function of Voltage and current (basically their multiplication, but it gets a bit more complicated for 3-phase AC with a poor power factor). Losses (heat) in the stator go with the square of that current, so to keep it from melting that current has to stay below a certain limit. If you need more power out of the rotor and stay below that limit you'd have to increase the Voltage coming from the rotor.

Increasing the air gap would lower the Voltage of the alternator for a given RPM, would it not? I'm no expert on PMGs, never looked into their design calculations. If your output Voltage is lower it means you have to limit your MPPT curve to a lower output power value than before, certainly at a point where the stator current is lower than before (in particular if your old stator burned out, meaning it couldn't handle the current).

To calculate the MPPT curve I'd need to know the exact rotor diameter, the Voltage vs. RPM relationship of the PMG (ie. unloaded Voltage is XX Volt AC between two phases at RPM YY), the TSR of the turbine, and the resistance between two phases of the PMG.

-RoB-

[Paul Camilli]

Hi Rob,

funny you should say that, I came to a decision last night, after a little 'tinkering' to reduce the air gap. Sadly this wasn't through any in depth knowledge of 3 phase AC theory, just my observation of how the turbine has behaved since I replaced the stator. To be perfectly honest it was a bit of a bodge, the turbine head is over ten years old and the new stator was slightly different. Rather than doing some drastic mods to the head I just widened the 'air gap' figuring it would help prevent overheating. The old stator had swollen a little with the heat and was touching the rotor so the air gap must have only been a couple of mm. In retrospect I guess I should have modified the head to suit the new rotor.

https://lifeattheendoftheroad.wordpress.com/2016/03/06/flying-again/

Just hope I can get it off again after using all that 'Loctite'!!!

Will keep you posted, my son is good at math, I'll see what he comes up with and you can check it for me.

Cheers, Paul

[Rob Beckers]

Paul, do you have any number for the maximum current that the stator will handle without burning up (it's up in the wind, so it gets some cooling)?

As I said, if you give me the numbers I can calculate a halfway decent MPPT curve for your turbine. It would serve as a good starting point that you can improve upon experimentally. It can also be made so the stator never gets overloaded.

-RoB-