voltage controlled current regulator

[(unknown)]

Hi, I have been searching for ages trying to find an example of a circuit that regulates/limits current depending on voltage input.

eg, when my wind alternator hits 16 volts it switches on the circuit and limits current to say 500ma. when it reaches 18 volts it automatically limits current to 1 amp, 20 volts 2amps, 22 volts 3 amps ect. linearly, if this makes any sense?

thanks.

[Nando]

My initial question : what you need this type of current limiting for ?.

It may not be for battery charging.

How many watts are you looking for ( voltage range and power).

Nando

[(unknown)]

it is for battery charging, I was hoping it would be useful in low wind days, even if it only charges at 500 ma its still utilising low winds.

[(unknown)]

I think this is the sort of thing I need. http://www.linear.com/pc/productDetail.jsp?navId=H0,C1,C1154,C1009,C1028,P2179

[WindJuggler]

Hello,

The easiest way to do this is with a PWM controller.

You use the A/D converter of a microcontroller to measure the voltage output of your windmill.

Then you use a Power mosfet to switch the load. A frequency of about 200-500Hz is fine.

Be aware that measuring the voltage output isn't correct if the battery is connected for loading. The loading current will make the voltage drop. I think it is better if you go with measuring the RPM of the windmill.

The first part of the numbers isn't linearly. The first part doubles instead of going up at a steady peace.

[(unknown)]

thanks wim, yes I should have added that frequency / rpm sensing would be ok too.

PWM controller might be a better way to go.

[Norm]

Smaller windmills with smaller alternators will

charge at 500ma in low winds....probably

     ( :>) Norm.

[Nando]

You want to charge a battery with limited current,,depending on the wind mill available power, this type of charger is one with MPPT ( Maximum Power Point Tracking).

There are some low power units like the ones produced by BZProducts.net which have MPPT and some may be OK for your system,

The MX60 is a more expensive and much higher current .

Quite a few want this MPPT capability but are not inclined in spending money on the charger or controller, I quite not understand it. !!

People spend a good amount of money to build and install the tower but can NOT spend the money for the electronics to properly manage the generated power with chargers the battery bank or for heating controllers.

my 0.0002 cents

Nando

[Devo]

Nando where does one buy one for windmills?, I would be interested.

Devin

[electronrancher]

Sure, we can build one of these.

So below 16v on the input (if i understood correctly) you want no charging.  Then linear from 16 and up.

So...  How do you prevent the device from overcharging your battery?  Can you give a little more detail?