Wind Turbine & Enphase IQ7 system integration success

WebPowerWebPower Registered Users Posts: 10 ✭✭
I've successfully connected an Enphase IQ7 to a wind turbine. Working out some kinks. Maybe someone out there is interested and maybe has ideas for some final tweaks that I need to do. Its based on the KSU research but has some tweaks due to IQ7 characteristics that are different from the KSU Enphase microinverter.

power production 24hrs a day, solar in parallel with turbine to provide power to black box interface during the day.
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  • BB.BB. Super Moderators, Administrators Posts: 32,216 admin
    I would be very interested in you posting your configuration/testing/results here on the forum (you can do it in this thread).

    And more information about your wind turbine too (actual daily/monthly harvest, brand/model/etc.). Finding HAWT (horizontal axis wind turbines) that are reliable and harvest significant energy in "normal" winds has been a unicorn hunt around here.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • WebPowerWebPower Registered Users Posts: 10 ✭✭
    The IQ7 has some interesting quirks to it when you try to do 24 hour production. First, Enphase doesn't plot in Enlighten any power production at night. However, the IQ7 does produce power. Enphase turns off cloud reporting based on your location. So I'm in Virginia and nothing is plotted between 11pm and 4am. The problem with the IQ7 I have to still correct for, is a non-production mode it gets into at times. I'm not sure yet when that happens, but it happens at night. It's happened three times in the last week. You have to cold start the IQ7 to get it back into service. Because I'm always providing it a DC bias, you have to unhook both AC and DC to it for it to restart the fastest. The things I still have to implement are:

    automatic cold start of IQ7 sometime during the night

    Implement a boost converter to fully utilize power production of turbine in low winds

    Once I figure out this forum's way to operate I'll post some diagrams and pics.

    More discussion/description to follow. I've posted several entries in the Enphase Community forum as well. But no real interest it seems there.

    Pat
  • WebPowerWebPower Registered Users Posts: 10 ✭✭
    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.
  • BB.BB. Super Moderators, Administrators Posts: 32,216 admin
    Interesting.

    What are you doing on the AC side of the micro inverter(s)? Are you using a PSW inverter (that may be optimized for running with GT inverters on the AC output) or something else?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • WebPowerWebPower Registered Users Posts: 10 ✭✭
    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
  • BB.BB. Super Moderators, Administrators Posts: 32,216 admin
    With the grid--You have "unlimited" energy storage... So now you are looking at having the choice of solar+GT Inverter vs HAWT+GT Inverter. This becomes a cost/maintenance choice between solar and wind turbine.

    My personal choice is usually solar power--Solar panels are (generally) cheaper and lower maintenance vs wind turbine.

    With GT Solar, you do not have "backup power" ability. In California, we (GT Power Customers) are required to use Time of Use billing...Currently, peak power is roughly 4 pm to 9 or 10 pm at night (high cost utility power)--In this case, having an energy source that can supply power when solar cannot--That could be of economic interest ($0.20 vs $0.40 per kWH hour for off peak/peak power costs).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • WebPowerWebPower Registered Users Posts: 10 ✭✭
    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. 

    Pat
  • WebPowerWebPower Registered Users Posts: 10 ✭✭
    Updates on progress. No non-production issue duplication yet. However,

    I have devised a method to perform a cold reset of the IQ7.
    HCW-M635 LVCO
    YX631 Time Delay Relay, mode C, 1 minute delay

    As a low voltage cut out, the HCW can be programmed to turn on at a higher voltage than the turn off voltage. Testing it, I can set it to 26v turn on, and 20v turn off. As the voltage slowly ramps up to the IQ7 turn on voltage of 22.5 volts, the M635 does nothing. once it reaches my set point of 26v it will turn on. That turn on triggers the YX631 to turn the relay on. AC to the IQ7 is across the NC of the relay, therefore it will open the AC to the IQ7 for one minute. Once the minute is over, the relay returns to NC resting state, powering the IQ7 back up and allowing the IQ7 to reboot. Since it's got 26v on the DC input, it will go into power production mode once boot up is complete. That in turn drops the DC of the super capacitor bank below 20v, turning off the time delay relay. Time delay relay off, powers down the YX631. In theory it should work..If the IQ7 takes more than one cold boot, I can handle that scenario with the same parts, just change the mode of the YX631 to keep repeating.

    So this will only happen if the voltage goes up past my IQ7 turn on voltage of 22.5v.

    Next thing being worked on is additional rectifier bank to put in parallel with the turbine output. I'm going to start plotting turbine voltage with a raspberry pi in preparation for a buck converter to produce power below the IQ7 nominal operating voltage. Stay tuned...

    Also, now that I figured out how to add pics, here are three plots from the Enphase cloud of the wind turbine's IQ7.Remember, there is solar in parallel with the turbine.

    First is normal morning turn on point from nighttime standby. Note the slight jump in green slope after 6pm which is the power supply turning on when solar is gone.
    Second is 40v DC non-production example. 3 times last week.
    Third is what happens when cold start occurs to correct from non-production mode
  • BB.BB. Super Moderators, Administrators Posts: 32,216 admin
    Is this still with your DC power supply "test source" or a real Wind Turbine?

    Getting real numbers from a real wind turbine installation has been far and few between here.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • WebPowerWebPower Registered Users Posts: 10 ✭✭
    This is with the turbine and solar combined. I'm almost where I'll be able to plot current and voltage for the turbine. Working on the programming now of the raspberry pi. I'd like to get an anemometer and couple that with the turbine measurements. That would give me the best idea of how its all working. I've got the second rectifier bridge installed and it's giving me independent voltage measurements from the turbine. This one will be for the voltage and the current measurement and tell me what is going to the super cap bank and then into the IQ7A. The bottom plot is for wind turbine today. The top plot is for a 420W dual sided panel/IQ7+ right next to one of the panels that powers the wind. It got a bit windy but was pretty cloudy until maybe about 1210 or so (we weren't home so don't know for sure). But you can see some influence of the wind. There were still clouds so I'm not entirely sure that some of the peaks aren't sun/cloud shading. If you compare the two, you see the wind IQ7A is much more noisy, which you could say is attributed to the addition of wind power. But the last little peak at the far right is wind only. That's where I inserted the additional rectifier bridge and was testing a boost converter into the circuit. It does add some measurable power. But I can't quantify it until I get the current shunt into the circuit and start gathering data. The little drop in DC at 5pm is where I was adding the rectifier in and shorted the super caps by accident. It's unusual that the IQ7 didn't turn off which is evident where it produced power from the boost converter add. Then the power supply comes on line and stabilized the DC at the end of the plot. Notice the daily peak of the wind plot where the IQ7 turns on and sucks all the stored power from the super cap bank. Most of the peaks are about 1 amp or so, about 15W it seems from the wind. That's where data collection will be helpful.

    I've never done this side by side comparison before. I'd say it's interesting and does show some added benefit from the wind.

    Pat







  • WebPowerWebPower Registered Users Posts: 10 ✭✭
    Since I've now got a solution for the non-production state, the main circuitry is working and should work on its own without intervention. Now I'm working on the final circuit diagrams. Here is a simple block diagram of the design. Detailed component circuit to follow...
    For simplification sake, the circuitry will not include power monitoring aside from a simple current and volt meter on the DC output to the IQ7. I'm working on that separately and have a raspberry pi installed measuring turbine current now to try to characterize the output of the turbine. I need to put an anemometer up and collect wind speed at the same time as turbine power so I can see what kind of power I'm actually generating from the turbine since I have solar in parallel with the turbine. Pat


  • WebPowerWebPower Registered Users Posts: 10 ✭✭
    Final design. Parts list to follow.


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