A Switched-Capacitor-Based Reconfigurable DC-DC Converter for Nanosatellite Power System

Nanosatellites have seen rapid growth in recent years, with their electrical power systems increasingly adopting unregulated buses and distributed architectures due to stringent size and weight constraints. However, the bus voltage of NanoSats fluctuates significantly (16 V to 60 V) during transitions between shadow and sunlight periods, posing challenges for downstream point-of-load converters. To address this issue, this paper proposes a switched-capacitor-based reconfigurable DC-DC converter capable of operating in both 1:1 and 2:1 modes. Additionally, traditional transformers face limitations in miniaturization due to proximity and skin effects. To overcome this, the proposed converter employs capacitive isolation techniques, leveraging switched-capacitor technology. The operational principles of the two gain modes are described, with zero-current switching (ZCS) and zero-voltage switching (ZVS) implemented to enhance efficiency. The converter's isolation capability is thoroughly analyzed, demonstrating its ability to block common low-frequency common-mode voltages through the isolation capacitors. This work also provides a practical hardware design approach, and a prototype is developed with a 16-60 V input, 15-30 V output, and a full-load current of 10 A. The prototype achieves a remarkable power density of 1900 W/in and a peak efficiency of 98.82%, demonstrating its potential for high-performance NanoSat applications.