Final Design

The overall design features three main components; the heating element, the cooling system, and the temperature transfer medium. These components are enclosed in the chassis and the heating and cooling system is controlled with external circuitry. Two circuits are used to measure the temperature of the TCU using Resistance Temperature Detectors (RTDs). A  MOSFET circuit is used to control the power distributed to the heating elements (RTDs) and also the cooling system which consists of a fan and heat sink.

Rounds of testing were done on the temperature control unit including initial performance tests and tests specified by the sponsors themselves. Two loops, A and B, were tested focusing on the heating of two different components of the temperature control unit. Additional cooling tests were done on loop A to test the rate of heat dissipating from the system

• Loop A: 

  • Heating measurements done on the heating element of the temperature control unit only

    1. Ramp from ambient to 50C & maintain temp for 10 seconds

    2. Ramp to 100C & maintain temp for 10 seconds 

    3. Ramp to 150C & maintain temp for 10 seconds

    4. Return to ambient temperature

• Loop B:

  • Heating measurements done on the simulated semiconductor, known as the device under test, through the transfer of heat from the temperature control unit

    1. Ramp from ambient to 50C & maintain temp for 10 seconds

    2. Ramp to 100C & maintain temp for 10 seconds 

    3. Ramp to 130C & maintain temp for 10 seconds

    4. Return to ambient temperature

Initial Tests:

Initial tests required finding if the thermal unit and semiconductor could reach minimum and maximum temperature requirements which can be seen below.

• Loop A: 

  • Minimum: 40°C

  • Maximum: 200°C

• Loop B:

  • Minimum: 40°C

  • Maximum: 130°C

Results:

Heating and Cooling Ramp Time Tests showed that the 4 RTDs in parallel could reach 130 C in an average of 53 seconds and cool down at an average of 17 seconds. Though these do not achieve original specifications, minor changes to future prototypes of the TCU could potentially improve ramp times

Final Tests:

Three ramp up tests for loop A and B were done to test if the TCU and device under test could reach and hold temperatures for 10 seconds. The test specifications can be seen below:

 Loop A: 

• • One: Ambient to 50°C

  • Two: 50°C to 100°C

  • Three: 100°C to 150°C back to ambient

• Loop B:

  • One: Ambient to 50°C

  • Two: 50°C to 100°C

  • Three 100°C to 130°C back to ambient

Results: