1Cloud CubeSat Thermoelectric Cooler Controller System

During the summer of 2010, our team developed a thermoelectric cooler control system as part of the University of Maryland-Baltimore County and Goddard NASA Space Flight Center Radiation and Climate Branch Cloud CubeSat Project. Our control system was built for Dr. Vanderlei Martins of the University of Maryland-Baltimore County Physics Department. We implemented a unity gain, closed-loop feedback system that read from a temperature-measuring sub-system. The system was controlled by a combination of an integrator and gain compensation and included a current amplifier to drive the thermoelectric cooler. We used a less powerful thermoelectric cooler than the Marlow device housed on the Cloud CubeSat and a less accurate thermistor (rated for 1 % error) to read the temperature of the cold plate of the cooler. The thermoelectric cooler reached the set-point temperature voltage corresponding to-30◦C in approximately 50 seconds. To our best knowledge–limited by the accuracy of our measuring devices–we achieved a steady-state error within ± 0.1K. We included a manual outlining the suggested changes to adjust our control system to the Marlow thermoelectric cooler