Enhanced high-fidelity and dynamic modeling for power conditioning units synchronized with on-orbit satellites

As a critical subsystem of satellites, the electrical power system provides stable and reliable energy for both the platform and payload against the harsh space environment. Satellite electrical power systems are continually advancing toward longer operational lifespans, higher reliability, and greater integration. The core of the electrical power system is the power conditioning unit (PCU), which controls, manages, and distributes electrical energy. A digital model of the PCU enhances design validation, optimizes assembly, integration, and testing (AIT) processes, and supports system operation and maintenance. Traditional PCU models typically focus on individual internal modules, resulting in incomplete representations and low model fidelity, which severely limits the practical applications. To address this issue, this article proposes a frequency-domain modeling and parameter optimization approach for the complete PCU module of the sequential switching shunt regulator (S3R) used in geostationary orbit (GEO) satellites. The first contribution is the development of equivalent mathematical models for the mid-frequency and high-frequency bands using spectral analysis, with optimized parameters based on magnitude and phase spectra. The second contribution involves virtual-reality synchronized experiments for on-orbit satellite and feedback regulation under typical fault scenarios. A key advantage of the proposed method is its ability to adaptively extract features from raw telemetry data, synchronize the input and output states of the satellite with the model, and enable real-time digital twin simulations. Experimental comparisons demonstrate that the proposed method improves system stability compared with traditional time-domain modeling approaches. The model demonstrates higher accuracy and superior dynamic performance by minimizing deviation from telemetry data and rapidly adapting to different operating modes and fault conditions. The results evaluate the effectiveness of the proposed approach in modeling for the satellite electrical power system.