Modeling and analysis of MEMS-based cooling system for nano-satellite active thermal control

The thermal control of developing nano-satellite will be challenging due to the continually rising tendency of the power densities on board and the complicatedly ever-changing orbital thermal environment. The paper is aimed at modeling and analysis of an active thermal control system for on-orbit nano-satellite used MEMS (Micro Electro Mechanical Systems)-based pumped liquid micro channel efficient cooling system. A thermal response model for the active thermal control system was established by means of lumped parameter method. Then an external orbital thermal environment nonlinear model was presented to simplify analysis of the environmental influence on the nano-satellite thermal control system. Based on the nano-satellite on-orbit case, the dynamics of temperature varieties of the internal electronic equipment was performed by the numerical simulation and calculation, and the PID control was done as well. Simulation results indicate that the combination of the MEMS-based single phase liquid cooling system and classical PID control law can satisfy the cooling requirements of on-orbit nano-satellite thermal system with high power generating components; especially, adoption of the advanced control theory for the active thermal system is necessary for autonomous keeping their payload within allowed temperature limits and also for achieving precious temperature control requirements. From these results, it is concluded that the modeling methods and algorithm are convenient and reasonable not only for the dynamical temperature calculation and analysis of nano-satellite, but also for developing control strategies of the nano-satellite thermal control system.