Regulator for 24v wind generator

[Thomas Medlin]

Would like to build a 24vdc regulator for a wind generator

 

[tcmtech]

Do you need to keep the generator loaded so it cant go over 24 volts or keep the power going to a device at 24 volts without going higher?

 

[Thomas Medlin]

24vdc wind generator regulator

The wind generator is a 3 phase ac perment magnet. The regulator supplied with it continually allows the dc output to go above 30vdc, hence causing problems with over charging and my inverter cutting out on over voltage.

As it is a 3 phase ac perment magnet I need to keep a load on the generator at all times. So once the batteries reach 28vdc I would then like to divert the power to another usable load.

 

[MikeMl]

...
As it is a 3 phase ac perment magnet I need to keep a load on the generator at all times. So once the batteries reach 28vdc I would then like to divert the power to another usable load.

Thomas, what is the max. current that the wind machine can deliver to the batteries during strong winds?

Are you familiar with a shunt regulator such as is sometimes used to prevent a solar panel from overcharging batteries?

 

[Thomas Medlin]

Max current of 24v wind generator

MikeM1, The max current at full wind speed of the 24v wind generator is approximately 20amps at about 30vdc.

I am not familiar with the shunt regulator, but feel this is the way to over come my problem.

The real problem is that my inverter has an over voltage cutout at 30vdc. Hence when the wind generator gets up just over 30vdc my invertor shuts down. What I would like to do is regulate it around 29vdc as I have no problem taking the batteries upto this voltage as it is supposed to be good for their long term life expectance.

Thomas

 

[MikeMl]

MikeM1, The max current at full wind speed of the 24v wind generator is approximately 20amps at about 30vdc.

I am not familiar with the shunt regulator, but feel this is the way to over come my problem.

Ok Thomas, the shunt regulator is just what it's name implies; it is a shunt path in parallel with the battery such after the battery reaches its full charge voltage, the excess current is shunted to ground, keeping the load on the wind machine relatively constant.

20A at 29.5V is almost 600W, so this raises the issue of how to dissipate 600W. Do you have any ideas of what you could do with the excess energy. Heat water, blow air, pump water uphill. The alternative is to heat a resistor which in turn heats air.

The real problem is that my inverter has an over voltage cutout at 30vdc. Hence when the wind generator gets up just over 30vdc my invertor shuts down. What I would like to do is regulate it around 29vdc as I have no problem taking the batteries upto this voltage as it is supposed to be good for their long term life expectance.

Would it be possible to put a series regulator between the wind machine and the battery bank/inverter. That way you could guarantee that the battery, nor the inverter will ever see a voltage above the regulator's output. But this raises another problem. Does the wind machine over-speed if there is no place for its output current to go? I'm asking "does the wind machine rely on having a constant electrical load on it for its speed regulation"?

 

[tcmtech]

Here is a basic adjustable shunt load voltage regulator circuit.
By adjusting the on and off voltages it will be possible to set the load bank to cycle full on at a high point voltage but not disconect until a lower voltage is reached.

I also posted a cheap but efective way to make load resistors in the **** chat area under Dumpster diver tips and tricks.

This should give you a basic but simple and reliable way to regulate your voltage with a load.

 

[MikeMl]

Here is a basic adjustable shunt load voltage regulator circuit.
By adjusting the on and off voltages it will be possible to set the load bank to cycle full on at a high point voltage but not disconect until a lower voltage is reached.

I also posted a cheap but efective way to make load resistors in the **** chat area under Dumpster diver tips and tricks.

This should give you a basic but simple and reliable way to regulate your voltage with a load.

That's a clever full-on, full-off shunt regulator. It minimizes power dissipation in the Power switching transistor, but still requires the load resistor bank to dissipate 600W.

I wonder at what rate and duty cycle it will be switching on/off.
Also, if you make the lower switching point too low, then while the switch is on, the system voltage could sag low enough to begin discharging the battery bank.

 

[tcmtech]

Thats the whole point of the adjustablity! You chose your high and low points!
The the rate and cycle are relative to the voltage set points, the size of the battery system, the charge being put in, and the actual resitance of the load bank.
As far as I know being able to set it to pull just a little off the top of the battery charge is not bad for them at all.

Given that a fully charge 24 v LA battery system actualy will sit at around 25 to 26 volts Idle, as long as the low level shut off is above that there should be no actual dischargeing taking place.

 

[Thomas Medlin]

In reply to the circuit posted by tcmtech, I think U1 is a 12v regulator and I'm not sure how to choose the values for R5 & R6 in refernce to zener diode D1. Also I'm not sure what Q1 IGB1 is. Is it possible to get a bit of a explanation on how the circuit works.
Much appriciated Thomas Medlin

 

[tcmtech]

U1 is a standard LM7812 voltage regulator. Q1 is any IGBT or Mosfet or group of them that has a high enough voltage and curent rating.
The zenere diode is the voltage referance for when the two comparitors change states. That is entirely up to the builder to chose.

R5 sets the high end of the adjustment scale. By chosing its value in respect to the zener diode referance voltage you will determine the highest limit the the comparitors can switch states at.

R6 sets the low end of the adjustment scale. By chosing its value in respect to the zener diode referance voltage you will determine the lowest limit the the comparitors can switch states at.

If you used a 5 volt zener with these R5 and R6 values your total range adjustments would be some place close to this.

R5 30K
R6 250K
High point trigger: 25 - 30 volts
Low point reset: 20 - 25 volts

R5 28K
R6 250K
High point trigger: 27 - 32 volts
Low point reset: 22 - 27 volts

These are just approximate voltages. Due to the wide variations in resistor tollerances the actual referance voltages will vary some.