It is running with 2.7 ohms. They shipped me the wrong resistor and said it would work OK. They said they talked to the ENGINEERS at SunG. LOL The only thing running on it is the little Effsun PMA. Most I have ever seen out of it is 600 watts at 40 mph.
Minnesota do you think I could make this mosfet work in place of the ssf7508? http://www.fairchildsemi.com/ds/FD/FDH055N15A.pdf I know that is a bigger package but I can make it work. Or could try two of these. http://www.digikey.com/product-detail/en/IPP075N15N3 G/IPP075N15N3 G-ND/2081152 Would get me up to 600 watt max dissipation.
Just cause I ask STUPID questions some times. LOL I was checking the ssf7508 and the irf3710 that we have found in the GTI for dump load. They both only have a max wattage dissipation of 200 watts. To me that would only be 400 watts continuous. Is that just wrong or what? Because I can just bet when it goes to dump the turbine takes off and the wattage is more like 600 watts when it finally connects to the dump load. Because even with my dump load terminals shorted last night. Both GTI's were making some power. During gusts even the relay switch would go on and off when a gust would come through. It did switch on and off pretty fast. It would drag the turbines both down pretty quick. That was when I saw the dump load glowing. And was doing some checking as to why.
Either of those FETS will work, Tom, but heat sink them well. They obviously try to use best-value parts but these sometimes prove to be unreliable if used hard. They have updated the normal DC and AC-side MOSFETS from the ones they used in earlier models due to many of their units failing in the field. Less seem to fail these days, plus the workmanship has improved. Yes, this over-volt circuit could be very fast acting, turing on and off rapidly. One would have to put a scope on it to see how fast it cycles. That is why one could see some watts still going to the grid and some going to the divert load. If you can study that area more, that would be helpful. A better design would divert power to the divert load while still actively inverting. They used a cheap-and-dirty method at least in this current generation of GTIs.
Tom/Minnesota, This may be a very dumb question...can we simply build a DC voltage regulator to go between the rectifier and the gti? Build it for 55volts to use on the 22-60v model and save the gti internals? This would take over at 55v and impose heavy loads to the turbine in order to maintain the voltage but should not decrease gti output compared to moments before hitting the limit.
That would require using mosfets at different states of conduction to hold voltage. Sure it could be done but at what cost. Also what would be the losses. My setup connects the dump load before the gti disconnects. If you adjust the resistor for the turbine you could maximize GTI output during this time. But go to large on the resistor and risk overspeed and DESTRUCTION. Input Minnesota?
I am hoping to find a way to keep the gti flowing instead of dumping. There is no good reason for a 1000 Watt gti to dump while only feeding 300 Watts to the grid. If it can't keep the voltage below 60 then I must finger a way to regulate it before the gti. I would rather burn off a few Watts to regulate than to dump everything..
Well I was playing around with dumping to a solar gti. You can not run it by itself. Because during fast rises it tries to lock on at 18 vdc and higher. Which worked well for low end. Most of the time it is sitting idle.I still needed dump load for really big gusts. In excess of a 25 mph increase in wind. But other than than that it never goes to dump.
Josh and Tom - the overvolt/divert port is obviously a cheap and dirty way for SUN to get into the wind GTI world without a major redesign. It's not ideal by any means, and it's terrible that it diverts all the power rather than just the excess over what it can invert. FETs are cheap, and it is possbile to develop a circuit that clamps the voltage at 55V but allows the amps to reach perhaps 20A. The same circuit could activate a 2nd GTI, perhaps at 45V, to allow both to invert when using a 1kW rated turbine (at 11m/s) like a HY1000. This circuit, and the multi-GTI switch Tom is developing, could be combined to provide a nice end-to-end solution.
It will be around $40-45. I just sent the board order in after 3 days of trying to shrink the size down to save $9 a board cost. First boards cost was $20. Which I can not use because it had the op amp on it. Now it is just $11 . Plus 24 items to squeeze onto the board. I will post when they are tested and ready. Will be about a month to get the boards as they send them out. Also will have to know if you want the leds with extension wires as to be able to mount in a box and still be able to mount leds in holes. But more on that later. Tell me at order time so I do not forget.
What for? The whole thing runs off a 1 amp supply. The input can take over 150 volts. That would only be 15 volts at the comparator and it can handle 38 volts.
My turbine might be capable of 180volts+ which would require too many gti's stacked without regulation.
The only one I know of with those kind of voltages doing MPPT or voltage regulation is Govertical over at Fieldlines. He is trying to control a F&P without modification. I think his voltages are higher. http://www.youtube.com/watch?v=b6PA71uhtjE
Tom, I did talk to him about his v4 board but he isn't confident about its ability to handle the load. Tell me if this will work.. Using 1 sun g 1kw 22-60v. What if I tie in a xantrex c40 in diversion mode? Put the gti in place of the battery bank. Hook up the 1500 Watt dump load to the c40 and program the diversion at 56v. When the gti cannot keep the turbine below 56v the c40 diverts keeping the fets in the gti from ever being used. Plus, since the c40 is designed to be battery tied AND discharge the batteries during dump, the gti will still be fed current so I will not dump 100% of my electricity being produced. Just enough to stay below 60volts. (I say this based on the wiring diagram of the c40 showing the turbine being tied directly to the batteries, or in my case the gti, and the c40 being tied to the input of the gti so to dump it simply will "share " the incomming current.) Thoughts?
Not a bad idea. I would wonder if the CC would have enough time to react since it will only get activated at the higher voltage as there is no constant voltage to keep it awake for any fast gust's? I guess you would also have to make sure the voltage never exceeds 60 vdc on the CC too? I am not sure if it can handle any more voltage then 60 vdc? Please keep us posted
Manual says it can handle 125v and 85 amps in short bursts. That should give time to divert or add resistance from a second load. The way I see it, this should let the gti continue to work while the controller bleeds off the extra that the gti can't handle.
