| The double-fed shaft generator system is an important part of the ship’s power system,and is an important and difficult point in the simulation training of the ship power station.Due to its complex structure and high simulation difficulty,the previous ship power station simulator still uses the traditional synchronous shaft generator.In this paper,the double-fed shaft generator system has been studied in depth,and some components have been accurately modeled and simulated.In order to be different from the traditional synchronous shaft generator,and to follow up the pace of updating ship electromechanical equipment,the new type of marine double-fed shaft has been systematically modeled and simulated,which lays a solid foundation for the research and development of double-fed shaft simulation operation platform.Firstly,this paper conducts accurate mathematical modeling of the excitation device,stator and rotor of the double-fed shaft by the mathematical model;Uses Matlab/Simulink software as simulation tools to conduct simulation analysis on various operating conditions of the double-fed shaft power generation system;And conducts related experiments by using the double-fed shaft experimental platform of the laboratory.The experimental results were compared with the simulation results,thus verifying the correctness and effectiveness of the mathematical model built.According to the working principle of the converter during the operation of the double-fed shaft generator,the principle of three-phase controllable rectification and the theory of electrical machinery,the mathematical models of the grid-side converter and the machine-side converter of the double-fed shaft excitation system are established.Matlab/Simulink softwares are used to perform dynamic simulation and in-depth analysis,obtaining the working states of the rotor-side PWM converter and the grid-side converter when the double-fed shaft excitation system works in the sub-synchronous and super-synchronous states.The simulation results conforming to the theory are then obtained.For the excitation current change problems caused by the change of the main engine during the operation of the double-fed shaft system,according to Faraday’s law of electromagnetic induction and Kirchhoff’s law,The mathematical models of the voltage,current,flux linkage,electromagnetic torque and other physical quantities of the stator and rotor of the double-fed shaft are established with the three-phase static coordinate system.On that basis,using the principle of Park transformation,the mathematical model in the static coordinate system is transformed into the state equation in the d-q coordinate system.Matlab/Simulink are used to carry out real-time simulation,analyzing the change process of each physical quantity in the sub-synchronization,synchronization and super-synchronization due to the change of the ship’s main engine speed when the double-fed shaft is operating independently.Through research and analysis,the change law of the phase sequence,frequency,amplitude,phase of the rotor excitation current of the double-fed shaft generator and the rotation speed of the main engine is obtained.For the functional requirements of the double-fed generator system,the virtual instrument control of the double-fed shaft system is written using Visual C#programming language and GDI+ technology,and the double-fed shaft simulation system is developed,which is an important part of the ship power station simulator and lays a solid foundation for the development of the double-fed shaft simulation operation platform.The simulation system has the advantages of convenient operation,strong professionalism,high model accuracy,and good real-time performance.It can be modularized and operated independently,or integrated into the power station simulator to operate as a whole.The successful development of this system is of great significance to improve the practical technical level of the double-fed shaft for the electricians or engineers. |
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