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I built a small fermentation chamber (cooling box) based on the peltier modules. I know this is not very optimal way as peltiers are not very efficient, but I had my reasons for choosing this way.

Basicaly I was satisfied - it worked decently. I used 2 pieces of TEC-12706 of which each has:

Qmax ~57W,

Imax 6.4A

and Vmax 16.4V.

I used an old ATX PSU which can deliver 18A max and supplied peltiers with 12V. I regulated the temperature of the box with simple arduino based regulation (just ON/OFF via 2 relays). All worked, but I would need a bit of more cooling power. So I ordered 2 pieces of TEC-12715 of which each has:

Qmax 136W,

Imax 15A,

Vmax 15.4V.

What I am trying to achieve now is having better regulation and not just on/off one as I read this is not very good for the peltier modules.

I read quite a nice "answer". It explains nicely how to create PWM based regulation for the peltier module, but it counts with the max current of ~6 amps. Is it possible to achieve similar pwm regulation circuit but for my setup which would either regulate 2 peltiers separately (2 circuits, each with max ~15A) or both peltiers (1 circuit with max ~30A)? I am wondering if I could modify the parts parameters of the circuit described in the link above to match my max current or if any other modification (adding MOSFETs, coils, diodes) will do the job. Or should I consider completely different solution?

Any suggestions are welcome.

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  • \$\begingroup\$ Is there any reason you need to treat the Peltiers as separate units, to be separately controlled? \$\endgroup\$
    – Brendan Simpson
    Mar 29, 2016 at 14:36
  • \$\begingroup\$ No, I do not need to control the peltiers separately. I just mentioned this way as 1 of the possibilities (in the case building single regulation circuit for ~30A max current is a problem). \$\endgroup\$
    – user241281
    Mar 30, 2016 at 7:27

1 Answer 1

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You can do them both in parallel on one circuit. You just need a large (40A) MOSFET or IGBT. IN this case, MOSFET would be far better, as you can just use an opto-isolator working from the Arduino 5V PWM to the supply voltage of the MOSFETs. You could also use multiple MOSFETs in parallel to achieve the same thing, though you may need a greater turn on current. You could also try cooling the MOSFETs fom the Peltier modules, which would use more power, but keep your MOSFETs nice and chilly. If you do not cool them with the Peltiers, make sure the MOSFETs have a large heatsink.

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  • \$\begingroup\$ Did you mean I can use the schematic diagram from here - electronics.stackexchange.com/a/118543/105099 and just use MOSFETs with at least 40A of max current? If so - how about the coils? Do they need to be replaced as well to be able to handle more current? \$\endgroup\$
    – user241281
    Mar 30, 2016 at 7:30
  • \$\begingroup\$ You can. I actually did not see that :) Just have two 18-20A MOSFETs and make sure that they are logic-level switched. If they are not, you just need a gate driver IC, which are not that expensive. Also, you will need to use higher current inductors. I would recomend Coilcraft for inductors, as they make amazing ones. I am not sure why there is a filter built into that driver though, it seems unnecessary. \$\endgroup\$
    – KilowattLaser
    Mar 30, 2016 at 17:25
  • \$\begingroup\$ P.S. Nice first question :) Mine got like 15 downvotes the first day, and probably deserved it :P \$\endgroup\$
    – KilowattLaser
    Mar 30, 2016 at 17:26
  • \$\begingroup\$ May I ask you for suggesting an example of the Coilcraft or any other 100uH coil which would handle around 30 amps? I am not able to find such coil. \$\endgroup\$
    – user241281
    Mar 31, 2016 at 7:38
  • \$\begingroup\$ USe two of these: Coilcraft AGP4233-104ME for each one of the inutors in the schematic (wired in parallel) and it will handle the current. It will be operating near the rating, but it is ell within it. They will each handle eight point three six amps, and each of the inductors in the schematic will have to handle about fifteen. So if you connect them in parallel, you will get the equivalent of 2X 16A coils in parallel, giving 32A of total current handling. \$\endgroup\$
    – KilowattLaser
    Mar 31, 2016 at 12:04

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