Wind Turbine & Enphase IQ7 system integration success

Even though the connection of a turbine to an IQ7 is highly desireable, its not terribly easy, but also not too hard once the details are all worked out.

As I mentioned, my system is based on the KSU research paper. However, the IQ7s operate differently than the M model of the research. My wind IQ7 starts producing power at 22.5v and then the MPPT clamps the voltage down to around 16v. I dont use a wind controller as they operate either at 12v, 24v, or 48v and the MPPT could really clamp at any voltage within the 15-48v spec. I use a diode bank from a wind controller I smoked during my testing. I tried a 24v turbine but its power curve is too high for my lower wind area. Many people write that they want to use batteries as the load bank for the turbine. With an on voltage of 22.5v and an MPPT clamping at 16v, i dont know of any battery that is compatible with those operating parameters. So like the KSU research, i use super capacitors. I didn't do the testing that KSU did to find the capacitance. I estimated based on their results.  I've moved to a 48volt 600W horizontal chinease turbine which my brother has loaned me to test with. Since I'm running at a nominal 16v, the turbine is de-rated to probably 200W or so. Its nice that the MPPT voltage is 16v in that the turbine produces power at a lower wind. However, I'd like to produce as low a wind as possible so thats why I'm looking at somehow adding a boost converter to the turbine for when its spin produces 5-16v as it wont produce power unless it has a load attached. 

Since the wind isn't up all the time, just like the KSU research, you need to provide a DC voltage bias to the IQ7 so it stays in a standby or on condition. If "off" it can take over 2 minutes to produce power once the "on" voltage triggers the software to produce power. A 48v turbines power curve allows it to teach my 22.5v on trigger voltage at a lower wind speed. The super caps allow the IQ7 to stay on during no wind transitions and will also keep tthe IQ7 on for a longer time. From standby state, the IQ7 takes less than 30 seconds to go into production mode. 

Since it needs a DC bias to keep the system working properly, why can't you use solar to power it you ask? Well, you can. I have 300 W of solar that provides DC bias to the system during the day. It powers a relay that turns off the DC power supply while the sun is shining. The solar and wind run in parallel. The only hurdle right now is overcoming the non-production mode that the IQ7 gets into sometimes. It has a high enough input voltage to turn on but doesn't. To overcome it, the fastest way is to do a cold start by removing both AC and DC from the IQ7. You can do it with simple relays once a day but why do a cold start if its not necessary. I'm looking at possibly using a small controller like a raspberry pi to make that kind of decision. Its a nagging issue that needs to be addressed. 

I spoke with Enphase today and the IQ7 reported errors of power production after dark, before dawn, and commanded reset during or near the latest non-production event. The only error worth worrying aboit is the commanded reset which usually means the microinverter is at a  too low of DC input voltage to operate in standby and is shutting down or restarting. It could be a byproduct of my transition from solar to/from DC power. So i'm in the process of testing nightime power production using a power supply all night on it. I might have to do something fancy to get it to enter the non-production mode. Once i reproduce it i can figure out the proper correction/solution.

It’s a normal Enphase grid tied install without battery. The grid is my battery. In the case of the wind micro, the AC does not go through an envoy. I have 6 other micros on that 240v line. It’s on my workshop power feed which is external to the house through a sub panel off the main breaker panel. We also have 22 micros on the house grid tied which are split between two breakers in an envoy combiner which go through a different sub panel. Those report through the envoy. I’ve not put an envoy at the workshop for its micros mainly due to being lazy. The cloud just isn’t happy and says I have a production/consumption error since there’s generation that it’s not seeing on a CT.

the entire system is a self install with all appropriate approvals.the State of Virginia and Dominion Power are great in that way. I’m net metered. Next July I’ll have a good estimate of overall electric savings. Right now it appears instead of 2019’s $2200 Power bill, 2021 should be under $800. Aside from wind, everything was finally done this July. I have about 9500W of solar total. There is a 10000W limit in Virginia before they institute a monthly generation surcharge. Solar is well worth it if you can do it yourself. My break even should be under 8 years.
pat

My playing around with the wind turbine interface is really just an expensive hobby challenge. In my area wind is not a cost effective solution that’s for sure. Once I get it all done I’ll compile a BOM and have a final cost for the interface. I’m sure it will make sense for some people.  

another challenge I’m going to take on is building a smaller solar tracking system. I’m going to use it on the turbine controller. For any of this I’m not worrying about cost, more trying to see if I can do it. It’s a hobby so like all good ones, it’s a money pit. I do this, my brothers pour money into boats…mine’s much cheaper. haha

I've always maintained that the most cost effective way to do solar with GT is to produce almost all your energy needs, no more. Net metering is perfect for that mantra. At your rates my payoff would be even sooner! And using a system with batteries that you can use the generated power during those peak hours would be good to have. Thank god I don’t have those issues.  Battery backup with my system would be fairly easy to implement due to the way my home’s power is configured. We have a portable generator so having the solar off during an outage isn’t a problem for us. I’ve had the generator solution way before the solar. And I agree that solar is the way to go. The only hassle is if you have a micro inverter fail. I had 5 fail all at once and it’s not fun changing it our by yourself with a 5 foot panel on top of it. 

Its all about the energy produced by the turbine and stored while waiting for the IQ7 to turn on and take the energy. Read the research here: https://krex.k-state.edu/dspace/handle/2097/8754.

Pat 

Sorry, I had a reply but never posted it.

No need to fuse it. The caps will only supply as much current as the micrioinverter takes. Ive regularly seen the initial surge over 10 amps. But it won't last long and I don't think its necessary.

Pat

Have bought my own 500W turbine and installed it. However it has an internal power transfer issue. The windings appear fine but it only has power on one leg of three.  I've done some characterizing of it and will post that soon. Once I get it back operational I'll redo the characterization to make sure it wasn't acting up when I was bench testing it. I'm starting to think it might have.

As you can see from the latest plot, it's windy. I'd be careful if going to a larger turbine as you're  probably going to need a larger capacitor bank. The one i have now works well to store up energy whike the inverter boots up on occassion..it regularly dumps over 10A to the inverter. I know  that's only 150W but you'll need to make sure the wire used can handle the 400W that the inverter is rated at. Not producing huge amounts from wind, but I only need about 800KWh of power over the year to make me even with usage and generation. Some tree trimming this month should help too. Last month we also reached the point where generation exceeds usage and the meter starts its negative ride backwards until the end of summer.  Our happy point in power production that happens a lot earlier in the calendar year than that point where you finish making more money than will be payed the IRS for the year.