Buck converter for small wind turbine project

[Burnit0017]

Hi, thanks for the information. Is this a complete circuit schematic?

[herbnz]

Hi, thanks for the information. Is this a complete circuit schematic?

No not complete just showing SCR control. combine with cct shown on backshed by warpspeed .
If you have problems I will spend some time and find out how to post a drawing.
Herb

[Burnit0017]

Hi, yes I am having problems. I save my drawing as a .jpeg file, then use the upload photo or image option that is offered at the forum. Any additional help will be greatly appreciated.

[rossw]

I save my drawing as a .jpeg file, then use the upload photo

jpeg is a lossy compression standard. It is poorly suited to saving line diagrams. You will get crisper lines and smaller images if you use gif.
That doesn't alter the uploading part however.

[herbnz]

I save my drawing as a .jpeg file, then use the upload photo

jpeg is a lossy compression standard. It is poorly suited to saving line diagrams. You will get crisper lines and smaller images if you use gif.
That doesn't alter the uploading part however.

Trying to upload

Herb

[MadScientist267]

Wow, been a little while since I've been able to get on and look at this. Coming along rather nicely from what I can tell. I'm going to have to go back a bit and find the exact point where I last kept myself in the loop.

Seems like every time I peek at this thread there is another alternator stacked on the assembly, maybe 2.

The rest of us aren't going to need to do anything about the "energy crisis" if this keeps up... Between you with the turbine, and Oz with the mega PV array, you guys will eventually be generating enough juice to enable the shutting down of every other power plant world wide. I just hope you guys got some REALLY long extension cords.

Keep up the good work man, it's a pleasure to watch this progress.

Steve

[Burnit0017]

Hi, I have established OVP concept drawing. The thyristors may be able to be replaced with Triacs, I am not sure. Opto-isolaters will be used to separate the DC from the AC. The book I am using as a reference is for motor control. This is a first attempt. Comments are welcome.                   

[rossw]

This is a first attempt. Comments are welcome.                 

OK. Constructive criticism, hope it's taken as such.

1. I doubt you can connect the gates together directly, across phases, in the way you indicate.
Its possible of course this is intended as a "functional diagram" only, and you will in fact have three, isolated trigger circuits.

2. Connecting the 3 triac/scr groups like that, with resistors to a common point, I think will come back to haunt you.
Since you must have two (minimum) devices ON in order to conduct, I've doubts that you can actually trigger them while there's no potential across them. It would seem (to me) to be a far better arrangement to connect your loads in  delta directly across the 3 phases (ie, one resistor/triac from A-B, another from B-C, and the last from C-A - that way, each will be directly between a phase.

[Burnit0017]

Greetings, I have found a possible solution for the over voltage protection circuit. The circuit located at number 4 uses the AC to trigger the circuit. I could duplicate the circuit 3 times, one for each phase. When the SCR’s are triggered the added resistive load would brake the turbine to lower the input AC voltage and the buck converter would continue to lower the voltage at the input capacitor of the buck converter on the DC side. I am not sure of the values required. D5 could be two 200 volt zeners in series for a 400 volt trigger. Comments welcome.

 http://www.circuitstoday.com/scr-applications 



It looks like the circuit reset its self. 

Thanks for input, it is very helpful

[Burnit0017]

Hi, If I can get the circuit working for single phase AC, this maybe a possible solution for a 3 phase configuration. Comments welcome.

[Burnit0017]

Hi, I tried to test the modified F&P with the OVP circuit. Because I modified the F&P stator I could not charge a capacitor to 400 volts to test to see if the OVP would trigger. I do have my moments.  RPM was about 600 and max voltage at the capacitor was about 350 volts with no load.     

Even if I add a 1:7 belt drive to the modified F&P I should be safe to road test with the buck converters.


I removed one of zener diodes from the OVP test causing the trigger voltage to be 200 volts. The OVP circuit triggered at about 200 volts and as I increased the RPM’s the voltage at the capacitor remained at 210 volts. The load resistor was only rated at 1 watt and became very hot but the circuit still functions. I have to increase the wattage rating of the load resistor.

It looks like the circuit will work for my application, if used with a wind turbine and the buck converters, the turbine will brake because a resistive load is added when the OVP is triggered and the input voltage at the input of the buck converters will remain at a save value at higher RPM’s.

[Burnit0017]

http://www.wisc-online.com/objects/ViewObject.aspx?ID=SSE5804


Hi, I found a tutorial explaining how the Zeners work in the OVP circuit. It really helped clear up my confusion. 

[Burnit0017]

Hi, this is the style blade I can fabricate. The C shape will have end caps.
The big question is what style will have better performance at average wind speeds? Please cast your vote, A, B, or C.

It is a election year.   

[Burnit0017]

Hi, making progress. Yes you guessed correct, no wind. 3 more blade to go.

[Burnit0017]

still waiting for wind