Hybrid Impedance Model and Stability Analysis of Dual-Channel Enhanced Power Generation System for More Electric Aircraft

High-voltage DC (HVDC) electrical power system is a promising architecture of future More Electric Aircraft. Commonly, DC impedance modelling has been traditionally employed to describe the system behavior. However, this approach tends to neglect impact of the d-axis of the AC side on the system and requires the inclusion of AC and DC grid-side parameters in the model, which can limit its ability to adapt to the complex changes in on-board working conditions. To address these issues, this paper proposes a hybrid impedance modelling method along with verification in simulation. This modelling method enables modular modelling of the system, allowing for the neglect of effects from AC and DC grids in the resulting converter model. Furthermore, the stability of single-channel and dual-channel power generation systems are analyzed in this paper. The analysis reveals that the rotational speed of the on-board permanent magnet synchronous generator (PMSG) impacts the stability of the HVDC system to a certain extent. Furthermore, while system stability can be enhanced by appropriately increasing the inner current loop bandwidth, as demonstrated in previous studies, this improvement is not without limitations. Specifically, there exists an optimal point for the inner current loop bandwidth, beyond which further increases may degrade system stability or even induce instability. The analytical findings are validated through simulation and experimental platforms.