A Modeling Framework for Stability and Dynamic Analysis of Marine Hybrid Electric Powertrains

This article introduces a modeling framework for electric and hybrid propulsion systems and presents a comprehensive set of stability analyses with onboard experimental validations. In the studied electric powertrain, a diesel engine (DE)-driven generator set feeds a dc link via an active front-end (AFE) converter, forming a hybrid ac/dc power system suitable for battery integration. A state-space system model is established, and small-signal stability analyses are conducted with a focus on the control parameters. Two types of analysis are presented such as stability portrait and sensitivity analysis based on eigenvalues. The findings highlight complex interdependencies between the control parameters, including the measurement filters, and the proportional gains of control loops. The analytical model is benchmarked and validated against time-domain simulations and experimental tests conducted onboard a vessel with a hybrid electric powertrain. Results highlight the model’s ability to mimic the real onboard power system under varying conditions, indicating the appropriate model fidelity and the ability to replicate the salient dynamic properties of the real system. The main outcomes include a detailed understanding of control parameters’ interactions and the identification of unstable operating points. The findings demonstrate the practical value of the presented framework in enhancing the operational reliability of electrified vessels and facilitating efficient system integration.