Questions about solar and wind regulators

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dedeleco
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by dedeleco » 01/10/12, 23:33

Completely agree with the basic comparators (which are also found in the op amp input stage, which is enough to use with low gain) and relays which turn the current on and off according to the necessary thresholds of steps and stop

This will recharge the battery between the correct voltage, from 12 to 14V, but without making the most of the wind turbine.


But the cow of a wind turbine is to give very variable tensions according to the wind and the current required.

With a small collection of comparators, we can adjust the optimum I currents of the wind turbine, with relays and series resistors, depending on the voltage it outputs when empty (or under load by analogically correcting the voltage under load U in U0 = U + RI.

But at high voltage we lose a lot of power in the resistor to reduce the voltage on the battery with a strong current.
This explains the use of a switching converter to adjust the voltage without too much energy loss !!

Otherwise, simply, you can charge the battery, elements by elements of 2V, connected in series, by relay, to have a battery portion voltage always close to that given by the wind turbine, this with a nice collection of comparators (or adhoc op amp, sometimes sold by 4 LM324 or 6 in a single circuit !!) ordering relays.
The assembly resembles that used to switch resistors in digital to analog converters.

It reminds me of montages for a completely different function, which I had done 40 years ago with a beautiful collection of relays.

If you have lots of batteries to charge, this is a simple, concrete solution, going back in time without microprocessors, without delving into their complexities and surprises, sometimes tiring.
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RV-P
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by RV-P » 02/10/12, 08:45

- Uh ... I don't understand you: why do you want that much to dissipate the excess energy in a resistance? Isn't there a way to reduce energy produced by the alternator without cutting into a resistance ? Broaden your reasoning "a little": there is a way to reduce the energy produced by an alternator without dissipating it in a resistor : I had spoken about it in the other subject "Self modified alternator for wind turbine" ... And if you fear the runaway of the wind turbine by strong wind and minimal load, there is a way to stabilize the speed by the not variable and even (I am preparing the diagrams) by the variable SPAN! The alternator of a car engine, is it not able to "digest" large speed differences (from idle to 800 rpm to over 12000 rpm, flywheel)?
- For vertical axis wind turbines, they are strong enough (like the stato-wind turbine) to withstand strong gusts of wind and Darrieus wind turbines are able to withstand winds of more than 250 km / h, with their small blades ...
- I saw a report on Chinese wind turbines which, instead of a fragile and prone to failure gear train, replaced it with magnets! Perhaps the author wanted to speak rather of an alternator with large number of poles, as it was made in the time of steam engines ... an adaptation of the frequency, by the passage by the continuous and a mono or three-phase inverter placed in the wind turbine or at its foot, despite the speed variation, we can generate very stable 50 Hz!
- @ +!
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dedeleco
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by dedeleco » 02/10/12, 14:05

RV-P wrote:- Uh ... I don't understand you: why do you want that much to dissipate the excess energy in a resistance? Isn't there a way to reduce energy produced by the alternator without cutting into a resistance

there are already, inevitably, losses in internal resistance easily strong alternator, depending on the size of the alternator relative to the wind turbine.
? Broaden your reasoning "a little": there is a way to reduce the energy produced by an alternator without dissipating it in a resistor : I had spoken about it in the other subject "Self modified alternator for wind turbine" ... And if you fear the runaway of the wind turbine by strong wind and minimal load, there is a way to stabilize the speed by the not variable and even (I am preparing the diagrams) by the variable SPAN!

by removing the span of the wind turbine reduced to its axis, we reduce the energy, but then as much not to put a wind turbine, if we lose almost all the energy available in the wind.

However, cheap pulsed voltage converters, with good efficiency, transforming any voltage between 2V and 150V into a stable voltage of 12 to 14V (or other value), exist with good efficiency going to 80%, with commercial integrated circuits where all the design work is almost done, and therefore instead of losing the energy of the wind, we can recover it to the maximum of what can give the wind turbine, if well ordered.

I don't understand why complicate life?

The alternator of a car engine, is it not able to "digest" large speed differences (from idle to 800 rpm to over 12000 rpm, flywheel)?

it takes an energy as variable as the battery needs it with its regulator adapted to the car and the battery, but very little adapted to a wind turbine where one seeks to obtain the maximum of power.
If we forget this objective, and the runaway of the wind turbine at high wind, it can work, paying attention to the very low speeds of the wind turbine which do not exist on an engine, which means that the alternator does not will give nothing at these low speeds.
- For vertical axis wind turbines, they are strong enough (like the stato-wind turbine) to withstand strong gusts of wind and Darrieus wind turbines are able to withstand winds of more than 250 km / h, with their small blades ...
- I saw a report on Chinese wind turbines which, instead of a fragile and prone to failure gear train, replaced it with magnets! Perhaps the author wanted to speak rather of an alternator with large number of poles, as it was made in the time of steam engines ... an adaptation of the frequency, by the passage by the continuous and a mono or three-phase inverter placed in the wind turbine or at its foot, despite the speed variation, we can generate very stable 50 Hz!
- @ +!

This is what is marketed, but sometimes with problems.
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RV-P
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by RV-P » 25/11/14, 10:00

- I think I found something ... Look by typing "34036 sepic" or "3843 sepic" in Google, in the "Images" section!
These are switching regulators whose voltage remains fixed despite the variability of the input voltage, higher or lower than the output voltage! And in addition, they are simple to manufacture!
- But for the 34063, it must be protected upstream against excessively high voltages, the 3843 having an internal zener diode!
- @ +!
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RV-P
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by RV-P » 02/12/14, 12:47

- So, I did a little experiment ...
- From this diagram:
Image
, and from this module, recovered from SONY CD player power supplies:
Image
, I modified it as follows:
Image
, as you can see in these diagrams:
Image
(figure 2)!
- Noting that it worked, despite a supply voltage as low as 2,5V (always 5V at output!), I can say that this diagram will work:
Image
- You just have to adjust the voltage and intensity according to what you want! If you "attack" Darlingtons or "Sciklay pairs" (pseudo-darlington, if you prefer!), You can charge big drums!
- @ +!
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by chatelot16 » 02/12/14, 18:50

this diagram is a voltage regulator! the power is determined by the load on the output, it is absolutely necessary that the source is able to provide the power ... it is not at all suitable for exploiting a variable power source

in the case of a variable source, it is necessary to seek the voltage which makes the maximum of power: therefore mppt for photovoltaic

for wind turbines the mppt is even more complicated because of the inertia ... when the mppt lowers the input voltage a little it instantly recovers more power with kinetic energy, but it slows down and then the power drops .. to obtain a wind turbine you need a smarter mppt ... or a simpler solution: an anemometer independent of the wind turbine and the regultion contains a table giving the optimum voltage for each wind speed

the diagram of power supply with cutting of the preceding message is not optimum at all: the input current passes in 2 transistor in series ... and the output current passes by 2 diodes in series

I prefer an inverter type decoupage: the month of the battery is grounded ... most of the source is grounded ... a single transistor charges the self ... we only diode discharges the self in the battery
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RV-P
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by RV-P » 02/12/14, 20:10

- And would it work in step down AND tension booster at the same time?
- I have seen inverter diagrams with precisely the 34063. We would have to see if they would work in "step-down-elevator"!
- We should also see this diagram, but with another circuit: the 3843, which is found in the power supplies of old cathode monitors:
Image
- But it only works from 9V!
- @ +!
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RV-P
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by RV-P » 12/12/14, 09:05

- Ah! Precisely: as these circuits have an intensity limitation, we should study how to make this intensity limitation (which determines the power!) VARIABLE!
Image (Sioux's trick!)
- From this diagram (Figure 2):
Image
, it should be possible to put in parallel on the resistances of 1 ohm and 6,2 ohms (which limit the current to 500 mA), a third resistance with a transistor (MOS-FET?) controlled in Pulse Width Modulation (PWM) ), so as to vary the limit current with the voltage supplied by the wind turbine! Of course, not on this circuit which limits absolute to 1,5A before grilling!
- I think we could do it from the famous 555 ... To study ...
- @ +!
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