Stability Analysis of Multi-Port MVDC Distribution Networks for All-Electric Ships

Abstract

Advances in the power electronics technologies, over the years, have opened up possibilities to consider mediumvoltage dc (MVDC) distribution network as a possible evolution of the existing medium-voltage ac (MVAC) distribution networks on large ships. MVDC distribution networks provide the possibilities to increase fuel efficiency and remove bulky transformers. However, to implement industrial scale MVDC distribution networks, some critical challenges exist, such as lack of standardised equipment, system-level stability, etc. This work studies the feasibility and stability of MVDC distribution networks when a distributed layout is considered. Due to the nature of the network, a multi input multiple output (MIMO) impedance stability approach is employed for modeling and assessment. The different components are modeled according to the existing industrial medium voltage technologies. The theoretical analysis is verified by full model time domain simulations. As a summary of the contribution, the main features of the proposed study are i) realistic identification of feasibility limits, ii) definition of design rules for capacitance sizing and best placement and iii) evaluation of distances for dc distribution cables and their corresponding inductances.

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

“…State-of-the-art research on the control design and stability analysis of DC SPS investigated the influence of design parameters on the system stability [15], and in particular finding the required capacitance and the cable length of the DC-grid as presented in [16]. Voltage stability is also studied against the negative effect of constant power loads (CPL) in [17]- [19].…”

Hardware-in-the-Loop Characterization of Source-Affected Output Characteristics of Cascaded H-Bridge Converter

“…This in turn also limits the bandwidth. Still, the demand for such equipment is growing due to the need to support the development of recent medium voltage dc (MVdc) and medium voltage ac (MVac) applications, grid integration of renewable energy sources and storage devices, energy transmission and distribution in the MV range [11]- [13] and assure safe integration with the existing apparatus.…”

Weighted Bandwidth Method for Stability Assessment of Complex DC Power Systems on Ships

“…Another case in which the CPL hypothesis is conveniently assumed is in [26], where the researchers put the focus on the method for designing a fault-tolerant stabilizing system. CPL is also adopted for marine applications [27,28], while [29] considers a limitation in CPL bandwidth. Other ideas to overcome the ideal CPL are in [30,31], where reduced-order models are defined.…”