Lead Lag Controller For Temperature Regulation (Peltier-based mini refrigerator)

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Hello there. Im trying to design a lead lag controller for a temperature regulation using peltier module. And im kinda lost and wanted to ask a few questions

The specifications are as follow:-
25x20x20cm Styrofoam Box (10L)
2 x TEC-12703 Module
2 x Heatsinks
1 x TMP102 temperature sensor
1 x Arduino

For now, I understand that there are 4 main energy that I need to consider which are,

  1. hot side to cold side transfer
  2. current generated for peltier
  3. heat caused by seebeck effect (heat pump)
  4. heat loss

For now, i am puzzled on the lead lag part, is the lead lag part is actually a "software" which is the coding ? How does it differ than a normal on and off control by the coding ? Do I need a MOSFET for PWM to implement the Lead Lag ?

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You also need a fan to move the air in the box.

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yes my heatsink does have it

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How do you plan to control the 3+ Amp current?

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using a MOSFET with PWM ?

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You don't need pwm for temperature control. Whatever on-off switch is fine, mosfet, relay...

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thats the thing, im not trying to do a bang bang control or a regular on off temperature control, im trying to implement a lead lag to increase the stability and reduce overshoot of the system, hence the question is what do i need to the lead lag possible ?

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First of all you need to get the setup working to cool the box, and a simple PID controller will be fine for that.

That will take some effort, so worry about the lead/lag software after you have the most important part of the work done.

With the PID controller, you may even find that there is no "undesirable frequency response in a feedback and control system" that needs improving.

Or is this merely a classroom assignment?

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thank you for your explanation, this is actually a design project which should be presented to my lecturer.

also the simulation has to be done before i can proceed on setting it up

and for your explanation, do i need PID ? since my lecturer said i only have to use Lead Lag controller, or does implementing lead lag requires PID first ?

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PID and lead-lag are two different transfer functions used in a closed loop controller, designed to meet specific goals.

In turn, deciding on the specific goals to be met requires analysis of the actual system to be controlled.

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PWM is harmful with many peltier diode units. Check this link, it has a good explanation as to why you want to control the current not the voltage. How to drive a Peltier element? - Electrical Engineering Stack Exchange and another with the math: 13.6 Lead-Lag Controller – Introduction to Control Systems while you are at it search for "13.6 Lead-Lag Controller – Introduction to Control Systems"

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thank you for the answers, but my main question is that, can i do lead lag control with just using a microcontroller ? or would it still be a normal on off control.

or do i need something to change the current or voltage, so that it sort of like an inverter in AC ?

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The MCU would acquire sensor data, do the required calculations and send output to the power controller.

1 Like
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On/Off would work but adding some smarts like watching the temperature change and compensating for the time lag by turning on sooner will help, also do the same when going the other direction.

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im using a 12V 16.5 power supply , how do i control the power supply ?

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i see, i do have another question , is Matlab or Proteus better to simulate this ?

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You don't control the power supply, the MCU controls the power delivered to the Peltier, using the Peltier driver module you have chosen.

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that means i have to use a driver module capable of 12V+ and at least 10A ? since im using 12703 module

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is this good enough ? BTS7960 43A High Current Motor Driver Module