晨昏轨道卫星硅太阳电池阵功率衰减估计

Estimation to Silicon Solar Cell Degradation of Dawn-dusk Satellite

摘要:

关于空间环境对近地卫星太阳电池阵输出功率衰减影响,以某晨昏轨道卫星的背场硅太阳电池阵为对象,在分析卫星轨道半长轴摄动、降交点地方时漂移、光照角变化、日地距离波动等因素的基础上,讨论电池阵工作温度和输出电流变化,建立电流与温度的拟合模型；同时以拟合电流归一化处理为重点,在光照角、功率温度系数归一化前提下,针对输入光源功率波动,提出利用温度进行归一化处理；最后利用实际在轨数据进行检验。结果表明,利用温度对光源功率进行归一化之后,太阳电池阵输出电流的数据一致性较好；在轨3年后,电流出现约2.35%的突降,推测电池阵串并联支路数目在40左右,且某个支路出现开路；功率变化具有季节性,冬至前后功率最强,夏至前后功率最弱；背场硅太阳电池阵功率衰减因子约为-1.034′10_^-5/d,年均衰减约为0.377%；预测卫星在轨17年后,夏至时期的电池阵功率衰减不超过8.5%；电池阵抗辐照性较强,适宜于近地空间长寿命应用场合。该方法可应用于在轨卫星长期测控与管理中的能源管理、遥测诊断与器件健康状态评估等方面。

Abstract:

With respect to output power degradation of solar cell influenced by space environment, a back surface field silicon solar cell array supplying power for a LEO (Low Earth Orbit) satellite running on dawn-dusk sun synchronous orbit is selected as a sample. Details on orbit semi major axis perturbance, LTDN (Local Time of Descending Node) shift, solar incidence change, and variation of distance from the Sun to the Earth are discussed. Situations involving solar cell array output current and working temperature are investigated and analyzed to build a fitting model from telemetry. To mitigate solar power variation influence, a new method has presented to normalize the fitting current with solar array temperature that is based on solar incidence and output power temperature coefficient. Validated by telemetry data, the results have shown that normalized current has a better consistency of degradation with a sudden declination of 2.35% after 3 years on orbit to indicate that solar array has about 40 branches among which one is probably open in circuit, and is high in winter and low in summer, and has degraded with exponential factor of -1.034′10_^-5/d that is equivalent to 0.377% annually. Prediction is that current degradation in summer is lower than 8.5% in 17 years of satellite working on orbit. Degradation illustrates that indigenous silicon solar cell has a better anti-irradiation performance in near Earth space and is applicable to LEO satellite of long life. The results can be used to assist power supply balance, telemetry diagnosis and device SOH (State of Health) evaluation for long term management of satellite in TT C (Telemetry, Tracking and Command).