Summary of doctoral thesis: Improving the efficiency in using double fed induction machine in shaft generator system on shipboards

Aims doctoral thesis: The application of doubly - fed induction machine on power-station on shipboard ensures that the two work modes working in parallel with the grid of shipboard and work independently when requiring.
Nội dung trích xuất từ tài liệu:
Summary of doctoral thesis: Improving the efficiency in using double fed induction machine in shaft generator system on shipboards MINSTRY OF EUCATION AND TRANING HANOI UNIVESITY TRANSPORT AND COMMUNICATIONS NGUYEN TRONG THANG IMPROVING THE EFFICIENCY IN USING DOUBLE-FEDINDUCTION MACHINE IN SHAFT GENERATOR SYSTEM ON SHIPBOARDS Major: Technology of Control and Automation Code: 62.52.02.16 SUMMARY OF DOCTORAL THESIS HÀ NỘI- 2014The thesis was completed at: Hanoi University of Transport andCommunicationsSupervisor: 1. Ass.Prof. Dr Nguyen Tien Ban 2. Ass.Prof. Dr Nguyen Thanh HaiReviewer 1:........................................................................................................................................................................................................................................Reviewer 2:........................................................................................................................................................................................................................................Reviewer 3:........................................................................................................................................................................................................................................This thesis will be defended at Universitarian dissertation Committee atUniversity of Transport and Communications.At ….hour…..date.…month….year.The thesis can be found at: National Library Library of University ofTransport and Communications. 1 INTRODUCTIONBrief The thesis studies the shaft generator system using doubly-fed inductionmachine on power-station on shipboards for providing solutions to improvethe efficiency of energy production and saving operating costs on shipboards.The thesis consists of: 4 chapters, 113 pages, 97 references, 54 figures andgraphs.Rationale While running on the sea, on the stable environment in climate andweather, the main engine propeller of shipboard often is not at full powermode, to take advantage of this excess power, the large shipboard often isdesigned with shaft generator working together with the diesel-generator. However, one of the complex technical issues is the stabilizing infrequency and voltage of the shaft generator when the speed of the mainmachine changing with the large limit, one of the effective technical solutionis that using doubly-fed induction machine working in generator mode. The advantages of DFIG in the power generation systems is that thestator is connected directly to the grid and the rotor is connected to thegrid through the control circuit. Because the control circuit is in the rotor,the power of the control circuit is much less than the power fed in to the grid,and the generating power is fed into the grid directly. Because of the above reasons, the author chose title “Improving theefficiency in using doubly-fed induction machine in shaft generation systemon shipboards” to perform the thesis.Aims The application of doubly-fed induction machine on power-station onshipboard ensures that the two work modes: 1.Working in parallel with thegrid of shipboard; 2.Work independently when requiring. In the thesis, theauthors delve into the ability to work in parallel with the shipboard grid byproposing a new structure with a simple control system, which is high quality,stable imitation of the grid voltage. In the thesis, the author also presents the method of caculating optimumangular speed of DFIG rotor so that the conversion efficiency frommechanical engergy into electrical energy in shaft generators on shipboards ismaximal. Hence, the transmission system between the main engine and DFIGrotor with the reasonable ratio of transmission is designed in order that the 2consumption of fuel for producing one electrical unit in shaft generators usedDFIG is minimum.The subject and scope of research The subject of thesis include of: - The doubly-fed induction machine. - The control system structure of the doubly-fed induction machine in shaftgenerator. The scope of thesis: Researching the shaft generator working in parallelwith the grid on shipboard.Results - The results of scientific is that proposing the new control structure of thedoubly-fed induction machine in shaft generator on shipboards, improving theefficiency in using doubly-fed induction machine in shaft generation systemon shipboards. - The results of practical is that reducing the consumption of fuel forproducing one electrical unit in shaft generators used DFIG, which plays animportant role in saving operating costs on shipboards. ***************** CHAPER 1: OVERVIEW OF SHAFT GENERATOR SYSTEM ON SHIPBOARD USING DOUBLE FED INDUCTION MACHINE AND RELATED RESEARCHS1.1 Overview of shaft generator on shipboard Figure 1.1: The system structure of shaft generator using doubly-fed induction machine The symbols in Figure 1.1 are as follows: 1.Propeller; 2.Shaft generator;3.Gearbox; 4. Main machine; 5.The controller of shaft generator power; 6.Thepower distribution cabinet; 7.The diesel-generator.1.2 The shaft generation systems in practices 31.2.1 The ways to layout for shaft generator to receive the energy frommain machine1.2.2 The electrical structure of of shaft generator1.3 The general diagram of the control system of shaft generator usingdoubly-fed induction machine The control circuit has two main parts: The grid-side converter c ...