Temperature stabilization using Peltier modules in highly dynamic environment

Abstract

The precision of the Inertial Navigational System (INS) is mostly related to the drift of the gyroscopes. Stability of biases and minimisation of drift can be achieved by highly and accurately stabilised temperature of sensors themselves as well as all related electronic circuits. In this paper, we present a very compact and economical solution for temperature stabilisation of INS with the use of Peltier elements controlled by a single microcontroller. The basis of the INS container is an aluminium block which provides the most homogeneous temperature field with its high-temperature conductivity. Temperature stability of the INS container is achieved by assigning a group of four Peltier elements to the sides of the block, each coupled with a temperature sensor. The aluminium block is isolated on all six sides, and the Peltier modules are the only "openings" for heat flux. The mathematical model of the Peltier element is derived and verified through measured performance. This model is expanded to take into account the influence of the environment as well as the internal heat source. Theoretical limitations are obtained using this mathematical model, which is later compared to experimentally obtained limits. This type of temperature stabilisation can be used for different purposes where precise temperature stability is needed in its end application. Temperature stabilisation achieved in this manner is highly adaptable to the changes in the object's surroundings and keeps the object's inner temperature stable. Groups of Peltier modules and temperature sensors enable the object to have fully independent temperature stabilisation on each of its sides, which in turn allows the temperature stabilisation algorithm to adapt its performance to the object's surroundings. All Peltier elements are controlled and monitored by a single microcontroller, which also exposes a simple and intuitive communication interface for the end-user. This concept was tested in a highly non-stationary environment with rapid changes in surrounding conditions, and the object's inner temperature was kept stable up to the second decimal. Hardware limitations were introduced, and the coefficient of performance was compared to its theoretical value.