The structural stability requirements of satellite optical payloads impose a stringent challenge on thermal stability. In active thermal control systems, conventional fixed-resistance heaters may cause temperature overshoot, thereby degrading control performance of temperature stability. To address this issue, this paper investigates the thermal performance of positive-temperature-coefficient (PTC) self-regulating heaters, whose electrical resistance increases with rising temperature, under two closed-loop thermal control strategies: proportional-integra (PI) and bang-bang control. The spatial temperature non-uniformity across the self-regulating heater surface is characterized, and its temperature control performance is compared with that of conventional fixed-resistance heaters. The results show that the resistance of the self-regulating heater increases with temperature, exhibiting a slow growth rate in the low-temperature region and an accelerated growth rate in the high-temperature region. The temperature difference across the heater surface increases during heating and decreases as the system approaches steady state. Under closed-loop control logic, the temperature fluctuation of the self-regulating heater gradually decreases as the target temperature increases. This phenomenon is more pronounced under PI closed-loop control and under bang-bang closed-loop control with narrow upper-lower temperature bounds. For conventional heaters operated at the same supply voltage, higher resistance results in lower electrical power and smaller temperature fluctuations, thereby improving temperature control accuracy. These results indicate that the selection and design of heaters should account for the satellite thermal environment to minimize power consumption redundancy. For the application of PTC self-regulating heaters, an appropriate resistance range should be selected to ensure temperature stability.

Self-regulating heater,Satellite active thermal control system,PI closed-loop logic,bang-bang closed-loop logic