Using a Outback MX-60 MPPT to control a PMA wind machine

[hmccoy99]

I have a MX-60 that I have been using on my solar array and my curiosity got the best of me.  I have tried paralleling an AIR 403 in star configuration with my solar panels

The panels are siemens 90watts x 2 rated at approx 5amps at 17.5volts I have them wired

In parallel and see at lest 30% boost in the output. on a avg day I collect .4 kw and a

max current of approx 8amps the lower output is due to sun shading. I have tried the panels in series and they will put out more power but work poorly if shaded.  I suspect

The MX-60 senses peak voltage and adjusts the MPPT algorithm to match.  I have tried

paralleling the modified AIR 403 with the solar panels with good results in low wind the 403 in star spins up better and in higher wind the unit is loaded more effiently and continues to spins without stalling with a large power gain. the input voltage to the MPPT is approx 20 vols and the output is 12v in approx 15mph winds I was getting > 11 amps. I appears the MX-60 adjusts the tracking in every couple seconds.

I see the problem with the solar MX-60 MPPT unit used as a wind controller as:

   1. It is not designed to adjust it tracking for wind machines fast variable voltage        conditions

   2. Shut down relying on the MX-60 protection circuit is not a good idea.

   3. over voltage same a #2

But I think if the input voltage swings could be smoothed to a time Constance of 2-4 seconds with a large capacitor bank. > 1 farad  and a voltage clamp/ diverter the

MX-60 would work very well.

I use a shorting switch to stop my units.

has anyone else tried this?

Henry

[scoraigwind]

I think Outback are modifying their controllers to work with wind 'as we speak'.  It has been tried before and I am told that using PV in parallel is helpful because the pv acts like a big zener diode.  come to think of it maybe boB should step in here because  he designed the MX60 and knows a lot more than I do about it.

From what I have read here, the Classic is a lot closer to being market ready than the outback controllers in respect of wind turbine connection at this time.

[boB]

OK Hugh, I'll byte... (just a little byte though)

A lot of people have hooked up MX60s to wind turbines, even without being "wind ready"

I'm not exactly sure WHY they sometimes work, but it ~might~ be because they happen to have a steady flow of wind instead of lots of ups and downs or something like that.

Yes, you can hook a solar array in parallel with a (small-ish) turbine, where the PV array "clips" the voltage at just above the temperature dependent Voc Voltage during battery full (etc) times... This works either day or night.  This can work fine as long as you are certain to add the PV manufacturers specified series fuse to the series PV string. So, the PV array MUST be able to handle the maximum current the turbine can put out at that voltage.  The turbine current cannot go above that series rating. Hopefully it's somewhat less than that to avoid nuisance breaker/fuse tripping.  This clipping method also works well in small hydro hookups.

   If the turbine and array are capable of about the same amount of power at the same voltage, then all is fine, as is with the old MX MPPT algorithm. But if the MX somehow finds the MPP Voltage of the turbine to be higher than the MPP V of the PV, then when the wind dies down, the MPP V will stay high until the MX sweeps again. This also means that the MX could possible see low power for a minute or two (or...) and might go to sleep and wake back up to do an initial sweep.  So you would want to be aware of behavior like this.

 The newer MF60 and MF80 should most likely work better than the MX in this type of hookup because when the power starts to go up with the wind speed, so should the input voltage of the MF. And when the wind dies down, the PV input voltage should come down again (i.e. dynamic tracking.)

Also, if you do use a PV array to clip the wind turbine voltage, use some PV voltage below 72V nominal to make sure it doesn't go above 150 Volts. Wire the PV array to have its MPP Voltage somewhat higher than the nominal voltage (12,24,48V) of the turbine I would say, because typically the cutin voltage of the turbine is going to be around the battery voltage and you want it to run slightly higher than the battery voltage to take advantage of all this.  For instance, for a 12V battery system, I'd try starting with a 24V nominal wired PV array with either a 12V or 24V nominal wound turbine, where the MPPV is around 33 Volts. You won't get any power out of the turbine until its voltage reaches at that 33 Volts (at least) but that's OK because open circuited, the turbine would probably have been higher than that anyway.

>>>I use a shorting switch to stop my units.

You will not want to short the PV input while the MX/MF is running though.  Make sure you disconnect the MX before connecting the short across the turbine and/or array.  The MX and most all MPPT controllers do have a few thousand microFarads of capacitance across their inputs already.

OR, you may just want to wait for a proper controller to come along first (MX or Classic) and use the MX60s built in diversion Aux output control temporarily.

If you're careful, it's a lot of fun to see this stuff work.

boB

[boB]

So I notice that you have an AIR403.  Doesn't this turbine have voltage limiting built in already ?  Maybe that was another SWWP turbine ?

boB

[hmccoy99]

It did have but I removed the control circuit and rewire it wye trying to get better low wind performance now the nomimal voltage is approx 17v.

Henry