Stability of Marine DC Propulsion Systems: A Review of Multiphysics Coupling Mechanisms and Hierarchical Enhancement Architectures

Objectives In order to enhance the operational stability of ships in modern high-energy applications, the stability of ship DC propulsion systems is systematically analyzed in response to the severe challenges posed by the coupled characteristics of multi-physical fields. Methods Based on the “electromagnetic-mechanical-fluid” three-dimensional technology model, we summarize and compare the stability research dynamics of ship DC propulsion system in recent years, and focus on analyzing the evolution mechanism of voltage oscillation, harmonic resonance, and electro-mechanical instability in the core technology route, energy efficiency characteristics, and control strategy. The key issues such as voltage oscillation, harmonic resonance and electromechanical instability are analyzed in terms of core technology routes, energy efficiency characteristics and control strategies. Results The study shows that: the voltage oscillation stage (in recent years) can control the voltage fluctuation at ±15% by optimizing the power electronic devices and control strategies; the harmonic resonance stage (2021-2023) adopts the enhancement of the response time and adaptive regulation to achieve the harmonic suppression rate up to 60%, and at the same time enhances the fault tolerance of the system; and the current systematic stage (2024 onwards) integrates the digital twin technology, high-frequency components and multi-field coupling model, effectively improving the system stability margin to two times, power system response time by 40%, fault prediction accuracy of 92%. Conclusions The stability study of ship DC propulsion system is accelerating the transformation from single field to multi-physical field synergy, and from passive response to active intelligent regulation. The research framework by integrating advanced power electronics technology and digital twin platform has become the mainstream direction for the design of next-generation energy-efficient ships, marking the system stability research leaping to a new stage of higher precision and lower energy consumption, and laying a solid foundation for the intelligent and high-efficiency operation of future ships.