Design and In-orbit Test of Small SAR Satellite Electrical Power System
- Paper number
IAC-14,C3,3,x22336
- Author
Dr. None None, None, Chile
- Year
2014
- Abstract
The HJ-1-C satellite is a small satellite of HJ-1 constellation which is also the first small satellite carrying Synthetic Aperture Radar (SAR) of China, in Low Earth Orbit (LEO). HJ-1-C is designed by DFH Satellite Limited Corporation and managed by the Chinese Ministry of Environmental Protection. As a small SAR satellite，HJ-1-C focused on some severe requirements for electrical power system(EPS), the 4kW peak emission power requirement with high repetitive rate by the SAR antenna and the volume and mass restriction of the whole small satellite. Corresponding to the requirement of SAR antenna and solid state amplifier (SSA), EPS supplies electrical power to SSA by an isolated 34V power bus which satisfies the SSA input voltage requirement as 33.5V，at the same time, solves EMC problem caused by SSA high repetitive rate. The 70Ah Ni-Cd battery and high efficiency solar cells of 34V power bus can guarantee a peak current for the SAR peak imaging. Before the input of SSA, 34V power bus designs a voltage close-loop circuit to eliminate 200A surge current generated by filter capacitors in SSA, and to protect the relays in power distribution unit (PDU). Because of the mass and volume restriction of the whole small satellite, EPS designs a solar array (SA)-battery union system in both 28.5V and 34V electrical power bus to satisfy the high power demand of SAR. 28.5V power bus supplies electrical power to the equipments except SSA. The SA power is conditioned by the PCU via a sequential switching shunt series regulator (S4R) operated under the control of a main error amplifier (MEA). The S4R function ensures, when required by the spacecraft users power demand (including the battery recharge power), to provide enough power from both the SA and the battery. The battery power is conditioned by battery discharge regulator (BDR). This paper shows the EPS design with particular attention on optimizing the battery intervention and dual primary power buses independence, improving the efficiency of battery discharge regulator and avoiding surge current when SAR demands high electrical power. Then this paper shows the analysis of on-orbit test TMs which demonstrate the efficiency and feasibility of the EPS design and its capability to support SAR peak emission power. Since HJ-1-C satellite launched in November 2012, the EPS has guaranteed the success of the satellite and its SAR imaging for more than 1 year.
- Abstract document
- Manuscript document
(absent)