The 800Amps wide range BUS current sensor for COSMO-SkyMed satellite

This paper describes a complete technical and performances overview of the Bus Current Sensor Unit (CUS) for the COSMO-SkyMed Satellite. The COSMO-SkyMed mission is very powerful demanding in terms of stringent operational modes requirements, with high peak power (up to 13.2 kW) load demand from the payload, providing a challenging set of engineering constraints to the EPS design. The major constraint is identified in the very high-pulsed power demand of the on-board SAR payload. The mission imaging capability requirements at EOL for one satellite of the COSMO-SkyMed constellation requires up to 750A to be provided by the Li-Ion Battery during eclipse period , in a repetitive pulses operational mode and with durations in the order of about ten seconds, The Current Sensor Unit (CUS), is designed to monitor the charge current for Battery Charger Module (inside the PCU) high accuracy feedback, and both charge as well discharge current, for Bus telemetry purpose. Due to the use of Li-Ion Battery for the COSMO-SkyMed in the Electrical Power Subsystem (EPS), the accuracy and offset specification for the Current Sensor performances, are close to the available state of the art for this kind of devices. A very challenging design was started, to get the best performances in terms of mass reliability and measurement accuracy. Optional full charge battery voltage control function is implemented, to allows maximum end of life battery performances. Summary of performance measurement and qualification result, as well as Power Subsystem integration test are reported.