I am experimenting with a peltier cell (thermoelectric effect). I want to use an H bridge to turn it off and on from the Arduino, change the polarity, and reduce and increase the wattage.
The only problem is that it consumes 5A and the most common arduino H bridges (L298N) as I have seen have a limit of 2A.
I have two questions, because I am inexperienced on the subject:
The H bridges do work for what I want to do (turn off, turn on, change the polarity, change the power).
Can you tell me if you know of a recommended H-bridge of more than 5A or 5A?
Use relays! My personal experience is you need to wait 5 minutes or more with good heat sinks on both sides, before changing polarity. The internal heat in the diodes must be dissipated before changing from cold to heat, or the opposite.
Paul
You can use those Mosfets from Farnell to make your own H-bridge.
They want you to buy 10 pieces and ask you for 5€ for doing it: Thats 10 Mosfets for 15€...
on resistance is 0.124 Ohm which gives you around 4x 3W @5A to dissipate...
Hmm... Ok. I found another one in DIL package, a little bit more expensive:
0.05 Ohm on state. here is the link to the spec-->
Ok, if you are ok with 40V source-drain you can use those dual N-mosfet with very low on resistance 0.0048 Ohm which solves your heat dissipation problem I believe-->
Thanks for your comment. I plan to put sensors on them and in the code I will put a conditional until a cold temperature does not arrive that does not change the polarity. What do you think? Do you think it's OK?
About DROK L298 Dual H Bridge:
It looks like a nice choice to me with an acceptable RdsOn-number at the P-channel power Mosfet in the H-bridge, 0.015 Ohm [RDs(on)] who gives you a low power dissipation figure at 5A. I guess the N-channel MOSFET has a similar number.
Still, the suggestion that the design is obsolete and you should instead try the device pointed to by @chris... might make sense! Looked at one of the products at Popolu and it's totally integrated. Besides, you can also sense the current passing the chip which is a nice feature. . I guess it will cost you some more but it might be worth it.
Still I believe the Amazon device might also be ok even if it is "obsolete"
Why are you posting a URL to people’s local router?
Driving a Peltier device is a lot different from driving a motor. You should never short it out.
The L298 is a very poor device to use at low voltages, it generates lots of heat. It is obsolete because it is so bad in the modern world of low voltage operation. Avoid it at all costs.
Ok Grumpy. It generate -some more- heat. But the question is:
Is it suitable to -this- particular application? AFAIK it seem to me to be bearable: As an estimate based on one of the H-mosfets on the device, raym3d will have to radiate some 5W of waste heat to some heatsink or maybe the card itself will dissipate it?
Of course it's unwanted but in an experimental context it might still be ok if the numbers in the spec are valid.
( On the other hand, techSpecs on Amazon are more or less insane. You must be lucky to get something in accordance with what you want...)
Just to double check (I apologize if the question is basic, remember that I am inexperienced), with this component I can control the polarity, turn it on, turn it off, change the power and sense how much power it is drawing from the battery, right?
I'll have to see if there is a tutorial on how to use it.
Most motor drivers use PWM to adjust the power.
This can't be direct use in peltier, as heat doesn't transfer during the PWM off period and the peltier effect is completely lost. (And cause seebeck effect.)
For power regulation, You'll need to add an inductor (and perhaps a capacitor).
I think necessary to show the module that can control the voltage or current for power adjustment from Arduino.
It need use it with the relay, for power control.
It doesn’t even have FETs inside it, it is just bipolar transistors.
Not only does that make it generate heat, but it severely limits the voltage it can produce across the device.
Yes it can. You can regulate the power with PWM. It can do this because the PWM frequency is many orders of magnitude faster than the thermal time constant.
However there is an argument that says using PWM may affect the long term reliability of the device.
That is a completely different issue. I suggest to use relays for on/off & polarity switch. If you want to control the current, you'll need to control either the voltage or the resistance, and a power transistor like a TIP 35C (or many others) would do the trick just fine if you drive it with a simple filtered PWM output. H-bridges are meant for applications where fast(ish)-switching is required, that is not the case here.
No.
The peltie is driven less efficiently than a constant current drive of the same power, even with PWM, which is well faster than the thermal time constant.
This is for reasons other than the thermal time constant.
Please read this documents Page:2 from TEXAS INSTRUMENTS.
The above document also wrote that a motor driver IC was used for polarity invert.
