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Forum Index : Windmills : Advice on MMPT and Inverter
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| briggsy Newbie  Joined: 06/09/2010 Location: AustraliaPosts: 4 |
Hello all you wise old windies out there. I'm a newbie but have been lurking for some time, long enough to buy myself a 2kw 360v Grid Connect Chinese turbine which came with controller and heat dump. The power output table supplied with turbine is shown below. I’m still learning about MMPT don’t quite follow how the Output (DC) peaks at 360V at 1010 Watts and stays at 360 V as the RPM increase and Output increases to 3120 Watts. I presume the amps must increase but don’t know how one would put this into the MMPT table. Example: RPM OUTPUT DC (V) OUTPUT (W) 64 110 31 191 240 136 239 280 265 287 320 670 334 360 1010 382 360 1519 430 360 2010 478 360 2211 Then 9 more steps until 673 360 3120 I’m currently looking around for a suitable inverter to match this turbine and am looking at the Aurora Power One and Ginlong and have two questions. 1. As the DC Output voltage peaks at 360V but the power and RPM keep increasing, how would one enter this into the MMPT for the inverter? 2. The Max Input for Ginlong is 9amps. For my turbine, presumably that’s 360V by 9 amps = 3240 watts which is past it’s peak power curve before furling. Does this mean I could use this inverter or do I have to go for something bigger(and more expensive) Windwise it will be rare for the turbine to produce more than 2kw but I don’t want to overload the Inverter. I’d appreciate any advice. |
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Greenthumbs Regular Member  Joined: 05/12/2008 Location: AustraliaPosts: 40 |
Hi Briggsy, Sorry don't know the answers to any of your questions. But at least I has responded to you! It seems that if no one knows the answer or it takes to long to find the answer or it is just too hard then Know one will will answer you. I have had the same experience with this forum. Not to say it is a bad site. It rocks but just to let you know we are freindly most of the time 
From What I know about wind turbines and grid tie inverters You generally need to turn Off the MMPT as the inverters can not handle the quick changes in voltage with wind power. However The Power One wind inverter is made for the job and MMPT is built in up to 580 volts So if you check out all the specks I think it would do the job (but I am No expert). I can say though that I own a Power One Solar Grid tie Inverter and it is great! and cheaper that the SMA stuff which I have one of as well. With My Power One inverter the inverter will DE-RATE if it gets too hot or is driven to hard. You will have to do some research. Download the installer manual and read it , sometimes this helps. Here is the PDF Brochure with specs for the wind Power One series if you have not got it. 2010-09-16_171832_pvi303642outdus.pdf Regards Damo |
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imsmooth Senior Member  Joined: 07/02/2008 Location: United StatesPosts: 214 |
I have the aurora 3.6, so I can answer for this one, although most of the principles will be the same for the Ginlong. The inverter has two sensing inputs: rpm and voltage. It uses this to determine how much current to draw off of the input line in order to get the right amount of power extraction. The technician at Power-one told me I should use the voltage as my variable, and not rpm. You have to choose one of them. You can not have multiple current levels at the same rpm or voltage. This is a mistake. A typical table would be something like: volt current 50 0.5 60 0.9 70 1 80 1.5 and so on... You have to keep the input voltage below a certain level. For the aurora it is 600v. If you exceed it you will blow the inverter. The unloaded voltage is linearly related to the rpm. The rpm is linearly related to the wind speed. Wind speed will determine the available power. All you need is to enter the current you want to draw at a fixed voltage and you have the power extracted by the inverter. Knowing this relationship, you can work out a formula to know how much power to have the inverter extract at various voltage points. If you want to see the calculation, let me know and I will give you a link to see how I did it. It has worked very nicely. |
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| briggsy Newbie Joined: 06/09/2010 Location: AustraliaPosts: 4 |
Thanks Damo and Imsmooth. Yes I thought the table supplied must have been a typo but as I'm new to these things I wanted to check. My regulator is set up to protect inverter. Once voltage gets past 380V it diverts surplus to heat dump and at 410V it electrically brakes turbine. By that stage it's producing more than 2.2KW and so would overload the Ginlong 2KW inverter I believe. I've only heard good reports about the Aurora so looks like that's the go, unless the larger Ginlong gets certified for Australia. Imsmooth, yes I'd appreciate the link to calculate my own table. Thanks. |
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| imsmooth Senior Member Joined: 07/02/2008 Location: United StatesPosts: 214 |
See if this helps. calculating data points for aurora inverter |
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| Greenthumbs Regular Member Joined: 05/12/2008 Location: AustraliaPosts: 40 |
Do either of you know how much the Power One wind inverter costs and if it is in Australia? I went with Latronics coz there was lots of people using it and so more help available. But if the wind power one is anywere as good as the solar one then that would be the best one too get. In your case with such high voltage one of the only ones. 
Damo |
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