Publication Detail

Quarterly Report On the Contributions from MIT to the Electric Ship Research and Development Consortium, January-March, 2009

Chryssostomos Chryssostomidis, Franz Hover, George Em Karniadakis
31 pp.

We have continued the development of an end-to-end simulation system for the All-Electric Ship (AES), including both the Integrated Power System (IPS) and Hydrodynamics. The new tasks completed are: (1) Sensitivity study of the 15-phase Induction Machine (IM) controller. (2) Modeling of the combustion turbine that drives the Synchronous Machine (SM). We present some technical details below and some representative results for both cases. In future work we will present simulation and sensitivity results of the full system for different scenarios.

We investigate the robustness of integrated power system layouts from a network theoretic perspective. We develop a new design methodology based on random network theory, in which network generation parameters are optimized for robustness to failures. Two approaches are proposed, one in which an entire network is optimized, and another in which a network added to a preexisting design is optimized. This latter approach allows given designs (line diagram detail) to be explored from a robustness perspective, without resorting to adding significant detail and running extensive simulation.

The main new accomplishment of this past quarter was the development of a basic motor estimation program to be used with existing propeller design software to jointly optimize designs of motor driven propellers. The existing 150 and 300 rpm, 19 and 38 MW, induction motor designs were also adapted to optimize operation at intermediate speeds of 200 and 250 rpm in order to verify the roughly linear dependence of the motor decrease in weight with increased shaft speed. The linear dependence results in weights slightly smaller than theoretically expected but still achievable if slightly increased heating of the rotors is allowed.

We have developed a nonintrusive power monitor for shipboard applications. Experiments with this monitor are reported in [2]–[12]. This power system diagnostic monitor uses existing power wiring to monitor loads. It is lightweight, cheap to install, and, because of its low sensor count, potentially highly reliable. References [13]–[19] demonstrate the NILM as a potentially effective tool for evaluating and monitoring shipboard mechanical systems through analysis of electrical power data. A key advantage of the nonintrusive approach is the ability to reduce sensor count by monitoring collections of loads.

The arrangement of the power wiring for these collections of loads determines the performance, accuracy, and usefulness of the NILM. During the reporting period we have conducted an analysis of the tradeoffs that affect the likely performance of the NILM in a real world environment, e.g., on board the USCGC Escanaba (WMEC-907) in Boston, MA. These tradeoffs bound the size of the collection of loads that can be monitored, determining the extent of the “nonintrusiveness” that the monitoring system can deliver in practice. A new ASNE publication of our analysis was published during the reporting period.

We have analyzed data from a Fall 2008 operational cruise of the ESCANABA, and conducted experiments that permitted the serving crew to use the NILM and its data for underway maintenance and for ensuring mission readiness. As is indicated in the attached letter, the crew found the NILM highly valuable in performing condition based maintenance (CBM) and underway repairs to maintain mission readiness.

In accordance with our plan, we developed further our models and employ them to study the response of a ship in a seaway. We developed all models for the hull, propeller, engine, generator, and motor, and included maneuvering equations for the all-electric ship in a seaway. We developed control protocols and simulated the response of the ship under transient conditions.

type: Technical reports

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Parent Project

Project No.: 2008-ESRDC-01-LEV
Title: Electric Ship Research and Development Consortium (ESRDC)

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