Model-Based Design of Marine Hybrid Power Systems - With a case study of DC Grid Architecture and Control
Doctoral thesis
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Date
2023Metadata
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- Institutt for marin teknikk [3437]
Abstract
Marine electrification and hybridization with DC power systems topology are still under development with advanced power electronics, energy storage systems (ESS), and their associated controllers to cope with stricter regulations for safety, reduced emissions, and improved energy efficiency. A design concept of the hybrid DC power system can bring a higher level of complexity in power and control system design due to the multiple converterfed power sources and loads and multilayered control systems. In addition, stability issues that can be arisen from design and operation parameters should be tackled during the design stage.
In this thesis, a model-based design strategy with stability analysis tools is proposed to achieve higher reliability, flexibility, and efficiency in complex ship hybrid DC power system design. A modeling approach that covers upper- to lower-level power and control systems is proposed for its application to the model-based design approach. The proposed model can be highlighted as an electromechanical system with variable-speed engine-driven generators, active front-end (AFE) rectifiers, ESS (battery and DC-DC converter), loads, and power filters. To interconnect the models and operate the power system, energy management systems, power management systems, and local controllers are proposed. Then, the proposed complete model is validated with time-domain simulations and large-scale experimental setups.
The results of the selected case studies demonstrate the effectiveness of the proposed method for the complex system design. For example, the proposed model-based design approach is applied to battery capacity sizing, filter design, load-sharing control, advanced power converter control, variable speed operation, etc. With these case studies, it is shown how the design and control parameters can be selected by obtaining limiting boundaries that assure system stability and higher efficiency.