Buck converter for wind turbine

[slowBurn]

Greetings, I am new to the forum. I am working on Buck converter that I can be used with a PMA for a VAWT project. 

The PMA and VAWT fabrication methods are establish.
I have road tested the VAWT and PMA, the highest output was 9 amps dc at 40 MPH. I was using a 12 volt deep cell as a test load.

Basically the faster the PMA spins the more it acts as a electric brake. The solution is to the problem is to add a MPPT controller.

Remove the micro  from the MPPT controller and a Buck converter remains.

I have fabricated a Buck converter that I am testing with the PMA.

Circuit parameters are :
Vin max = 100 volts DC
V out = 13.7 volts DC
I out max = 15 amps DC
Switching frequency = 20 kHz (this can change if required)

Problems encounter during first phase of testing:

Damaging DMV’s measuring current. I believe they are over heating and self destruct.
Searching for a better way to measure current.

Control circuit IC Vcc is from a 7812 connected to the battery.
Is there a circuit configuration that would work using Vin? Than the system would power down during periods of with no wind.

555 timers have voltage spikes during transitioning of waveform that resonant throughout the circuit. Is there a circuit configuration to dampen the voltage spikes?

I have limited power electronics and I would like to select a off the shelf output inductor that will handle 15 amps continues. Any recommendation will be greatly appreciated.

I have had limited success manually spinning the PMA and illuminating a 12 volt 50 watt halogen light.

I am able to adjust the switching frequency duty cycle manually. Duty cycle range is from 10 to 50 %. I am using this approach to gather data to have a better understanding of the MPPT algorithm. 

I am currently using two IRF540’s in parallel.

Comment welcome.   

Videos of projects:
http://www.youtube.com/watch?v=EKH7DJKxryw

http://www.youtube.com/watch?v=gdnsGDhNH4w

[slowBurn]

Hi, additional photos and video of project

http://www.youtube.com/watch?v=B3dLzZZ5jKQ

[Hero999]

Thanks for posting your project.

I think the best solution for the inductor is winding your own. A ferrite core designed for use in an SMPS would be ideal.

[slowBurn]

Hi, I did order some toroid inductors, thanks for the suggestion. Can anyone recommend a IC that will up clean the timing signal from the 555 timer? There are positive and negative voltage spikes that are transmitting through out circuit.            

[Guest alyna]

thanks for posting that.... my father want also to have like that but his not keen into research...