Solar Cell as a Capacitive Temperature Sensor

Spacecrafts in geostationary Earth orbit and low Earth polar orbit experience temperatures in the range of -180 degrees C to 80 degrees C [1, 2] depending on the orbit. Solar cells are mounted on light weight aluminum honeycomb panels which are deployed and Sun pointed in on-orbit operation. Solar panels charge batteries and supply power to the satellite during sunlit period and batteries supply power during eclipse period. The open circuit voltage (V-oc) of a silicon solar cell varies by about -2.5 mV/degrees C [3] and temperature can bring about a dramatic change in the solar cell characteristic, particularly with reference to operating voltage. PRT mounted on the rare of the solar panel measure the temperature of the solar panel. This introduces errors due to temperature gradients between solar cell blanket and solar panel and slow transient response of PRTs. A method of using solar cell capacitance to measure the temperature of solar cell blanket is proposed. This removes error due to location and transient response of PRT. Solar cell as a temperature sensor for measurement of temperature is demonstrated.