Dynamic Modeling, Stability Analysis, and Power Management of Shipboard DC Hybrid Power Systems

This article proposes a framework for the stability analysis and control testing of marine hybrid power systems with dc power architecture. The dynamics of such active systems are increasingly influenced by interactive modes, such as the highly dynamic loads and varying load sharing scenarios, electromechanical modes, and integration of energy storage systems (ESS). Hence, a dynamic model of the entire system is developed, including the power electronics and ESS, electromechanical systems, different controllers, low level and high level, and propulsion loads. The proposed analytical model is used to establish not only the small-signal stability analysis but also time-domain simulations. Then, a set of dynamic analyses and tests has been performed to identify the stability challenges that a vessel may be exposed to during a real operation. The suggestions for improving the system performance are given as the control modification at different levels. To emulate the real operation, a ship operational profile is used for the tests. Finally, the proposed dynamic model is verified with the experimental results conducted in a full-scale hybrid power systems laboratory. The results show that the system dynamics can be affected significantly by the interaction of the high- and low-level controls of the converters, which is usually neglected in conventional models.