im just a amatuer but looking for a device that i can not find.
could anyone help to create a list of parts to buy and a program to run (i have some experiense in arduino 3d printing programming)
im looking for a simple PWM device
i got a wind turbine that in storms will put out to much voltage for my controller to handle.
normally the safety feature just will diverse 100% of the power generated in to a dumpload and the controller shut off.
i want to harvest the power possible in all wind.
so im looking for a PWM devise that will sense the voltage generated and use PWM to diverse some of the energy to a dumpload but ONLY to keep the voltage at the maximum point of the controller, and the controller can still be on and harwest the power in to the battery bank
im thinking arduino with a small screen and some navigation buttons to select maximum volt allowed and also in real time display voltage in the line(s).
Doesn't your wind turbine's manufacturer have any options for this?
The voltages you mention are something to be very careful with, and I may assume that there are pretty significant currents involved as well.
Your description of what you want is the description of a SECOND controller to be switched in as controller when the source voltage gets too high. Do you know what the voltage will be the instant you switch, under load, from the old controller to the new one? Approaching infinity! Well, close.
What are your plans to switch back to the original controller when the wind dies down?
Paul_KD7HB:
Your description of what you want is the description of a SECOND controller to be switched in as controller when the source voltage gets too high. Do you know what the voltage will be the instant you switch, under load, from the old controller to the new one? Approaching infinity! Well, close.
What are your plans to switch back to the original controller when the wind dies down?
Paul
yes it wil be 2 controllers in paralel in a way but the first one is full MPPT.
the second one (arduino) is just to add more resistors to the circuit to take down the voltage.
the resistor wil be a few water heating elements in my floor heating system.
as i said second one wil NOT switch on or of it need to be PWM and automaticly adjust the pulsewith to keep the voltage down to selected
option could be a relay for safety that shut ewrything off if volt adjustment fail.
this do not turn the orginal one off the arduino add inn paralel to the other to take down voltage if nessesary, its just for safety in extremly high winds
wvmarle:
Doesn't your wind turbine's manufacturer have any options for this?
The voltages you mention are something to be very careful with, and I may assume that there are pretty significant currents involved as well.
as i said orginaly there is just a dump load that make 100% of the power go in to heating of the air and bechause all the power go out there is nothing left for the controller to work on.
thats why i want to remove only the top, the voltage that is over the max rating, that way the controller will still work as normally and it will newer get damaged from too high voltage bechause the arduino wil by PWM skim of the top voltage and ampers that goes with it.
total its about 3kw at the top rated voltage so ampers are mannageble
I'm not sure what kind of help you expect... Nobody can give you a schematic for something like this.
im looking for a simple PWM device
Have you looked-into how switching power supplies/regulators work? The pulse-width is determined by hardware-feedback in a hardware-oscillator. (If a microcontroller is involved it's used indirectly, it's not generating the PWM.) The voltage/current is smoothed with an inductor.
thats why i want to remove only the top, the voltage that is over the max rating
That's not how [u]PWM[/u] works. PWM gives you the full-voltage but since it's pulsed you get a lower average voltage/current. When you dim an LED with the Arduino, your eye takes care of the averaging. With a power supply an inductor (and usually capacitors) does the smoothing/averaging.
total its about 3kw at the top rated voltage so ampers are mannageble
Maybe for you... The Arduino runs in the ballpark of 1W and we can touch it without getting killed. At 3KW there's a good chance that you'll fry a few components during development/testing/debugging. ...The 1st time I built an AC dimmer, I tested it a 12VAC with a light bulb from a car.
This is simple to do on the dc side, much more difficult on the ac side. Since simple is a relative term, simple here means easy if you're experienced in power electronics design.
The concept is that you monitor the dc voltage and when it exceeds a threshold, you turn on the resistor(s). Typically, you PWM them (the resistors) based on the level of overvoltage. Higher bus voltages equal longer on times.
For 3kw, you can probably build a chopper (that's what they're called) with a big-a$$ 500 volt N-channel mosfet but it will need a real gate driver circuit, it would not be directly drivable from an Arduino. You've got to dump a lot of current into the gate quickly to get the device fully turned on to minimize the heat rise/losses. You'll have to watch the current, a function of your heater resistance. And of course you'll need bigger than expected heat sink since most 500V 30 amp mosfets are in the 150-200 milliohm range which puts a 10 amp load at 15-20 watts into the heat sink.
Expect to blow up a few devices getting it right. High speed fuses and safety glasses are an absolute must at these power levels, faults have a habit of creating rather high speed airborne molten balls of copper, aluminum and silicon. No synthetic fabric clothing is a good idea as well, it tends to melt into your skin when hit with the molten copper and aluminum.
No synthetic fabric clothing is a good idea as well, it tends to melt into your skin when hit with the molten copper and aluminum.
Excellent advice, but I would add a full face shield, preferably hung from a safety helmet, so you don't bash your head backwards when the board explodes.
DVDdoug:
I'm not sure what kind of help you expect... Nobody can give you a schematic for something like this.
Have you looked-into how switching power supplies/regulators work? The pulse-width is determined by hardware-feedback in a hardware-oscillator. (If a microcontroller is involved it's used indirectly, it's not generating the PWM.) The voltage/current is smoothed with an inductor.
That's not how [u]PWM[/u] works. PWM gives you the full-voltage but since it's pulsed you get a lower average voltage/current. When you dim an LED with the Arduino, your eye takes care of the averaging. With a power supply an inductor (and usually capacitors) does the smoothing/averaging.
Maybe for you... The Arduino runs in the ballpark of 1W and we can touch it without getting killed. At 3KW there's a good chance that you'll fry a few components during development/testing/debugging. ...The 1st time I built an AC dimmer, I tested it a 12VAC with a light bulb from a car.
im sorry that i do not explain well enough, i wil try to make function blocks for arduino:
1 AC volt reading wetween 3 lines coming from generator
2 AC reading over set value = pwm +5%
3 AC reading still over set value = pwm +5%
4 AC reading within set value = do nothing
5 AC reading under set value = pwm -5%
6 AC reading under set value = pwm -5%
as for physical stuff, since its complicated to do AC wee are going to DC no problem but the arduino still need to read AC to monitor the corect voltage entering the 1 controller
Function for physical stuff:
1 wind turbine
2A wires enter 1 controller
2B in paralell with 1 controller AC volt reading for arduino
2C in paralell with 1 controller all 3 lines in to rectifier
3 from rectifier in to solid state relays
4 from relays in to water heating elements (dumpload)
5 solid state relays controlled by pwm output from arduino
for the arduino to read as high voltages maybe some voltagedeviders need to be added before the input of the board but thats fine to compansate in the software and still get accurate voltage readings
avr_fred:
This is simple to do on the dc side, much more difficult on the ac side. Since simple is a relative term, simple here means easy if you're experienced in power electronics design.
The concept is that you monitor the dc voltage and when it exceeds a threshold, you turn on the resistor(s). Typically, you PWM them (the resistors) based on the level of overvoltage. Higher bus voltages equal longer on times.
For 3kw, you can probably build a chopper (that's what they're called) with a big-a$$ 500 volt N-channel mosfet but it will need a real gate driver circuit, it would not be directly drivable from an Arduino. You've got to dump a lot of current into the gate quickly to get the device fully turned on to minimize the heat rise/losses. You'll have to watch the current, a function of your heater resistance. And of course you'll need bigger than expected heat sink since most 500V 30 amp mosfets are in the 150-200 milliohm range which puts a 10 amp load at 15-20 watts into the heat sink.
Expect to blow up a few devices getting it right. High speed fuses and safety glasses are an absolute must at these power levels, faults have a habit of creating rather high speed airborne molten balls of copper, aluminum and silicon. No synthetic fabric clothing is a good idea as well, it tends to melt into your skin when hit with the molten copper and aluminum.
it wil be made from comersial avalible parts.
my 1 controller wil take 2kw away so the rest max 1kw need to go somwere else to not damage the 1 controller, if this power is constant and predicteble its not a problem, just add a relay and a dumpload and its fine.
but the power over 2kw is not predictable and not stabile, but the watt follows the volt so it can easely be adjusted by the voltage on the generator output and the current dont matter just have to use big enough opamps and mosfets.
or if its possible use solid state relays, did not look at their maximum switching frequency yet but mosfets could be used for sure
could something like this be used for the AC monitoring input on the arduino?
its rated 250acv so it wil not work without modifiction or another model,
anyway toughts?
edit:
if measured between hot line and ground only half of the AC voltage vil be detected so then this item is fine to use, need 3, one for ewry hot line
It is not a way for lowering the voltage. My heater is in household socket with 230V and the regulator regulates power by 'cutting out parts of the the AC wave'.
Juraj:
It is not a way for lowering the voltage. My heater is in household socket with 230V and the regulator regulates power by 'cutting out parts of the the AC wave'.
i see, i ment that in my case it can not be used due to higher voltages and i still have no system to read the AC voltage (hopefully someone here could help with a arduino board for that part)
but the power over 2kw is not predictable and not stabile, but the watt follows the volt so it can easely be adjusted by the voltage on the generator output and the current dont matter just have to use big enough opamps and mosfets.
Minor mistake you made there... the watts do not always follow the volts. The watts follow volts times amps and for a constant resistance load, the wattage goes up at the rate of volts squared divided by the load resistance. You might want to take that into consideration when calculating the resistor(s) required.
You also say the power above 2kw isn't stable. How does one control the voltage of a source that's unstable? The answer is simple, you can't! That's why the controller just dumps it.
Commercial wind turbines feather their blades and point the nacelle into the wind when the wind speed exceeds the generators ability to control its output. I think there should be a lesson in those facts.
avr_fred:
Minor mistake you made there... the watts do not always follow the volts. The watts follow volts times amps and for a constant resistance load, the wattage goes up at the rate of volts squared divided by the load resistance. You might want to take that into consideration when calculating the resistor(s) required.
You also say the power above 2kw isn't stable. How does one control the voltage of a source that's unstable? The answer is simple, you can't! That's why the controller just dumps it.
Commercial wind turbines feather their blades and point the nacelle into the wind when the wind speed exceeds the generators ability to control its output. I think there should be a lesson in those facts.
again my bad explaining
i ment that the wind turbine have a linear voltage and aperage curve so it wil be no suprises.
im not going to calculate any resistors bechause i want PWM and then the softwase should adjust accordingly to what load is present, if it turns out that its not enough i wil just add another water heater element in paralel.
is this post better to post in the software forum?
i have concluded what parts i need and already ordered them from ebay.
what i need now is:
what arduino to buy
what screen with buttons to buy
what powersupply
and the code for program
Perhaps consider a mechanical/hydraulic speed governor on the turbine output. Usual safety mechanism is to lock out or feather the rotor main drive blades.
bluejets:
Perhaps consider a mechanical/hydraulic speed governor on the turbine output. Usual safety mechanism is to lock out or feather the rotor main drive blades.
yes im looking at ghyro brake, it wil apply automatically when overspeeding.
other than that the load on it wil also slow it down, another safety could be a timed output that wil activate if the hz goes to high basiccaly short the output and it wil brake the turbine maximum
