As to the ripple problem of the direct torque control system of permanent magnet synchronous motor, this paper present a new method based on the fuzzy logic control. The new method replaces the traditional hysteresis torque controller by a fuzzy logic controller to realize the low ripple effect of the torque and the flux linkage. Also this paper modeling and simulate the new control system using the FIS toolbox provided by the Matlab/Simulink software, and the simulation results shows that the fuzzy control method is far more better than the traditional direct torque control system.
A nonlinear model for the marine high-voltage transformer is established which based on the J-A theory , considered the eddy current loss. This model accurately reflects the nonlinear characteristics of the transformer, and does well in describing the dynamic process, it is propitious to design the ship transformer and the study of relay protection. A fourth-order Runge-Kutta algorithm is used to solve the nonlinear differential equations to ensure the model has a high accuracy, and the pre-magnetizing model is also established. At last, through the transformer no-load closing simulation results verified the correctness of the model.
The mathematical model of the ship autopilot system is established which centering on marine hydraulic steering gear, based on the Nomoto ship motion model, and considered the influence of wind, wave, flow and other environmental factors on ship course angle. Depend on this model, the physical-digital hybrid simulation autopilot simulator is developed. This simulator has all of the operating functions of the ship steering system, it can not only simulate the turbine engine working scenarios, but also dynamically display the operation process, and the simulator is applicable to the ship track control research and crew training work.
Aiming at the present deficiency of operation examination for marine engine, a simulation system of marine engine based on virtual reality is developed. In this paper, the virtual scene and 3D entity model of marine engine is constructed by 3DS MAX according to the actual situation of engine room and the specific operation requirements, and then the 3D model is driven by DirectX in the environment of Visual C++6.0 to achieve the functions of VR scene roaming, human-computer interaction and operation examination. The VR simulation system developed as a part of the whole marine engine simulator can supply an almost real environment for the crew operation examination, which will greatly improve the operation ability of crew, being of important significance for the reform of crew examination in China.
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