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Forum Index : Windmills : IGBT shunt controller
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imsmooth Senior Member  Joined: 07/02/2008 Location: United StatesPosts: 214 |
I know most of you use battery banks, but some may be interested in grid-tie solutions. I developed my own IGBT shunt controller that stands by in case I lose the grid. It will turn on if the voltage exceeds 235v and divert the power to a dump load, keeping the voltage and blade rpm down. The voltage threshold can be set to whatever value one wishes. The unit works off of voltage between 0 and 350v. I have tested it with an 8 ohm load at 250v and it works well. I am providing a link to the webpages. These pages also go into creating and developing your own circuit board which some may find interesting and useful. Click here to go to the link. |
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GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
Hi imsmooth, An 8ohm load is a serious amount of power at 240V, 7.2kW at full duty cycle. If the grid is down, better to just use an interlocked relay, and electrically turn OFF windmill. I think what you mean is to provide a load during the time that the GridTiedInverter [GTI] is not connected to the grid. The Solar type GTI are notorious for losing grid connection with a windmill. I used an SMA SunnyBoy with limited success with additional componentry. Better to use a GTI that has a smarter system, to maintain grid connection during brief low wind periods. The AC anti-islanding still functions normally though. The system I have is now commercially available in Latronics GTI's. I am working on a Triac loading system now, having already looked at separate rectifiers and Mosfet and IGBT heater systems. Gordon. PS Have just looked at the link, and this must be for a multikW system. Are you OK with having such a high static loading that does not get to the grid? The heaters in the low voltage power supply are as much as the base loading on my entire house. become more energy aware |
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| imsmooth Senior Member Joined: 07/02/2008 Location: United StatesPosts: 214 |
I guess I was not clear. Sorry. I tested the unit with 8 ohms and 30A. The actual load is 30 ohms/4000w which you can see in the schematics. My point with the 8 ohms was that the IGBT could handle the large current at that voltage with no problem. I tested it with a voltage multiplier at 30A. I watched the unit cycle back and forth without a hitch. I would have tested it at 350v, but I didn't have my workarea set up for that kind of current. The purpose my my controller is for when grid goes down. My Aurora has been pretty reliable so far and has not lost a grid connection. The inverter is a dedicated wind inverter, and has nothing to do with solar. What did you mean by a high static loading? |
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| GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
Hi imsmooth, An extract from your pic. 
There is about 100mA @ 250V. This is a high static load of about 25W. I keep the static control cct current to below 30mA @ 5V. I would power the unit from an AC plugpac, and have relay interlocks for power failure. Gordon. become more energy aware |
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| imsmooth Senior Member Joined: 07/02/2008 Location: United StatesPosts: 214 |
I thought about connecting it to the mains and using relays, but I wanted a self-contained unit. The unit only uses 25w at peak power; it is much less when the voltage is lower. Is there a significant problem with such a high static load? |
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| GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
Hi imsmooth, only 25W!! Before anything happens, this power is consumed in a dropping resistor. It remains the whole time the windmill produces enough power to feed the grid. The current will be approx half, at half the voltage. I would expect that the inverter will have approx 180VDC minimum nom input voltage when connected to the grid. I work on reducing wasted power to a minimum. I would think that the active parts of your cct could be selected to only draw a few mA. Probably could replace the 2300ohm resistor with a high voltage constant current source. This could reduce power by a factor of 10-20x. You are only using a zener sensing, so power supply would not be too critical. Gordon. become more energy aware |
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| imsmooth Senior Member Joined: 07/02/2008 Location: United StatesPosts: 214 |
The problem I was trying to solve is that I need enough current to rapidly charge the IGBT gate's capacitance to rapidly go to saturation. I wanted the device to function without any external (grid) voltage source, so it had to develop a stable voltage to power the ICs over a large voltage range (0-350v). THe 2300 ohm resistor allows the 18v voltage regulator to do this. The shunt controller, and hence the 2300 ohm resistor, is not in series with the inverter. It is in parallel, so nothing interferes with the inverter getting power. The inverter feeds to the grid starting at 50v. That's only 1w. At 100v it's only 4w, and at 150v it is 9.8w. I know I am wasting power, but I didn't see a way to solve the problem: 1. be able to turn on if the voltage exceeds a certain threshold with or without the grid being active 2. turn on at a specified voltage (234v). If the grid is down, I still need to be able to shunt power. If the grid is active, but I have not established a connection I still need to be able to divert power. If the voltage exceeds a certain threshold I will destroy the inverter. However, if you have a better idea, which I am always interested in, I wouldn't mind seeing a schematic. |
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| GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
You have moved on from the F&P by the looks, unless you have a mini windfarm. Gordon. become more energy aware |
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| imsmooth Senior Member Joined: 07/02/2008 Location: United StatesPosts: 214 |
It is more like an oak tree farm  |
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| alfa156 Newbie  Joined: 21/04/2012 Location: ItalyPosts: 1 |
Hi, am new to the forum, I read some threads, I have a generator model windmax hy 600 watts, 24 volts. I burned the charge. Now I realize it with the means I have a charge controller. I decided to make this project http://www.thebackshed.com/windmill/articles/TL084-Controlle r.asp But instead of using relays for load dump, a Toshiba IGBT MG75J2YS50 possibile.Il not know if it's my system with 24 volt batteries. If you can, some of you have an outline for the project? Thank you for your help. |
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