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Author Topic: Buck converter for small wind turbine project  (Read 9143 times)

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Burnit0017

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Re: Buck converter for small wind turbine project
« Reply #15 on: February 26, 2012, 06:07:31 AM »
Hi, thank you for the suggestion.

 The photo displays the Vs wave form on top and the IR2117 trigger input on the bottom. I am using switching diodes because I do not have any fast recovery diodes.

The only way I could get the MosFet to turn off is to connect  Vs from the IR2117 to ground. Control signal is 10 kHz and I am using bench power supplies and a 12 volt light for a load.

I am making progress. 

Burnit0017

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Re: Buck converter for small wind turbine project
« Reply #16 on: March 02, 2012, 04:49:06 AM »
Hi, I managed to resolve most of the problems with the proto circuit when using the bench power supplies.  They were mainly caused from the power supplies and I had the new oscilloscope probes set to x10.

I still have to resolve one problem. The output from the 555 oscillator has a severe ringing that is transferred to Vs of the mosfet.  But the boot strap appears to be working with the Vs from the IR2117 connected to Vs of the mosfet and the mosfet is turning on and off.

kam

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Re: Buck converter for small wind turbine project
« Reply #17 on: March 03, 2012, 15:47:19 PM »
how did you solve the problems from the power supply????? what sort of filter you used?

Burnit0017

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Re: Buck converter for small wind turbine project
« Reply #18 on: March 03, 2012, 17:26:12 PM »
Hi, I found a manual for the power supply on line.

http://cp.literature.agilent.com/litweb/pdf/06284-90002.pdf

The bench supplies were configured with the positive terminal referenced to ground.
When I reconfigured so that the negative terminal was referenced to ground all the problems were resolved.

I am currently searching for away to supply the IC’s with Vcc. I am not sure if I should use a 12 volt linear regulator from the 12 volt battery bank or if there is a method to use the large input capacitor at Vin. The voltage at Vin can range form 0 to over 200 volts open circuit and I do not know how fast the buck converter will drain the cap at Vin when the mosfet is oscillating. Comments are welcome.   

Burnit0017

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Re: Buck converter for small wind turbine project
« Reply #19 on: March 04, 2012, 05:40:02 AM »
http://youtu.be/omrqepe4rCo

http://youtu.be/ATZ7Tfr_JQ0


Hi, video shows manual operation of PMA and buck converter to a resistive load.
The mosfet is turning on during the off cycle of the IR2117. Is there a solution to this problem???  Comments welcome.

kam

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Re: Buck converter for small wind turbine project
« Reply #20 on: March 04, 2012, 09:51:17 AM »
if the gate of the mosfet is floating, funny things happen. it can be turned on even with a sufficient external field. maybe?

Burnit0017

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Re: Buck converter for small wind turbine project
« Reply #21 on: March 05, 2012, 06:27:37 AM »

http://pcbheaven.com/circuitpages/Triangle_Wave_Generator/
http://www.pcbheaven.com/circuitpages/Voltage_Controlled_PWM_Generator/


Hi, I found some circuit examples the that can replace the 555 oscillator I am using. It may solve the ringing problem. I will post result when available.

Burnit0017

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Re: Buck converter for small wind turbine project
« Reply #22 on: March 10, 2012, 05:23:05 AM »
http://www.youtube.com/watch?v=B3dLzZZ5jKQ&feature=youtu.be


Greetings, I added the larger caps to the boot strap and the ringing is still there but only noticeable at lower RPM’s.

I am still using the 555 timer. I increased the duty cycle to 80% and inverted the output so the duty cycle at the input of the IR2117 is 20% high. I connect a 12 volt 50 watt light and spinning the PMA manually I was able to illuminate the 50 watt light with relative ease. Wow, a shorter duty cycle made all the different. The PMA was much easier to spin and even maintained momentum for a short period when I stopped spinning the PMA.

Without the buck converter I was unable to illuminate the 50 watt load under manual operation. 

I am still using the bench power supply to power the IC’s.

Performance has definitely improved.

I still need away to control the duty cycle at different PMA RPM’s and find away to power the IC’s from the battery or PMA. Next step is to try charging the battery. It maybe time to start thinking about adding a micro controller. Thank you for all the suggestions.     

kam

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Re: Buck converter for small wind turbine project
« Reply #23 on: March 10, 2012, 09:54:53 AM »
very nice mate!  8)

the 555 won't help you with the pwm change though. the microcontroller is as always a good solution. As for the ringing, i'm not sure what else to suggest.