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Author: search.filters.author.Ramesh, U. S.Subject: search.filters.subject.Tugboat

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    Energy saving strategy on electric propulsion system integrated with doubly fed asynchronous motors
    (IEEE, 2016-11) Singh, Raja R.; Chelliah, Thanga Raj; Khare, Deepak; Ramesh, U. S.
    Electric propulsion system integrated with doubly-fed asynchronous motor contributes efficient characteristics and flexibility in operation. However, in perception of energy saving and full-scale speed variation, the conventional doubly fed asynchronous motor is limited by the ratings of power converters. Generally, the electrical machines are designed to attain maximum efficiency around the full load. To increase energy saving and operating speed range under lightly loaded condition, the proposed strategy injects a low voltage DC supply to the stator winding instead of full rated AC supply. Wherein the DC supply is obtained from the converter's DC-link instead of external source. The proposed system is mathematically modelled using Matlab/Simulink tool and implemented experimentally with a 2.2 kW doubly fed asynchronous motor. In addition to this, the comparative energy conservation analysis of an electric propulsion system (2 MW) with the proposed strategy is carried out as a case study.
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    Control strategy for fuel saving in asynchronous generator driven electric tugboats
    (IEEE, 2016-12) Anil Kumar, B.; Anil Kumar, K.; Radha, T.; Chelliah, Thanga Raj; Khare, Deepak; Ramesh, U. S.
    Usually electric tugboats are equipped with diesel engine based electric generator for power production, battery for supplying power to auxiliary loads and electric motors for propulsion. This paper proposes control strategies for diesel engine and electric generators used in electric tugboat to improve energy efficiency of the system. Doubly fed induction machine (DFIM), asynchronous in nature, is considered in this research which serves as generator (power production). The speed of diesel engine is controlled in accordance with the power demanded by the tug. Output voltage and frequency of generator during sub-synchronous operation are regulated by controlling its rotor current with the help of power electronic convertors. Comparison of fuel consumption at fixed and variable speeds of operation is performed. From the test results, it is observed that the variable speed operation of diesel generator offers significant reduction in fuel consumption.
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    Improved fuel-use efficiency in diesel–electric tugboats with an asynchronous power generating unit
    (IEEE Transactions On Transportation Electrification, 2019) Anil Kumar, Birudula; Raghu, Selvaraj; Thanga Raj, Chelliah; Ramesh, U. S.
    High capacity diesel–electric tugboats are employed at every modernized harbor for assisting big marine vessels and other harbor applications. Contemporary tugboats use multiple power sources to meet their propulsion and auxiliary on-board load demands. The effective utilization of multiple power sources leads to better fuel use efficiency with reduced emissions, economic, and environmental benefits. This paper presents a simple optimization technique for scheduling available power sources of a diesel–electric tugboat [diesel engine generators (DEGs) and batteries] to meet its load demand with an objective to minimize fuel consumption. For this paper, a diesel–electric tugboat system of 1.1-MW capacity with different generating systems is considered: 1) fixed speed generating unit (2 × 550 kW fixed speed DEG employing synchronous generators) and 2) variable speed generating unit [1×1.1 MWvariable speed DEG employing doubly fed induction generator (DFIG)]. From the optimized test results, it is inferred that the variable speed generating unit offers a fuel saving of 29.86% in comparison with diesel-mechanical propelled system and 2.9%in comparison with fixed speed diesel– electric system. The simulation of a 1.1-MW variable speed generating system is performed in MATLAB/Simulink 2014A environment, and experimental demonstration is performed through a 2.2-kW laboratory prototype