The Research Of Drive Control Technology For Large Ship Crane

Large crane is the key equipment.for developing offshore oil. Based on the construction costs, maintenance costs and other factors, the several world's large crane are available with electric drive at present. As the electric grid will have a greater impact when lectric drive crane is operating, and it may even result in serious loss of electricity grid, and then an accident, this article will start the study for driving control technology of electric drive crane.The load of crane owns the characteristics of constant torque, which can limit the rate of change of power by limiting the crane acceleration and deceleration rates, and then it can ensure that the ship power grid voltage and frequency fluctuations in the extent permitted, and also it doesn't affect other electrical equipment of the ship electrical grid stable operation.In this paper, I have taken the practical three-phase synchronous generator of fifth-order model. In the excitation system, this paper has taken the model of controllable phase-compound excitation brushless excitation system which not only can reflect the relevant physical quantities, but also the mathematical model with sufficient accuracy. In the speed control system, at present, most of the research literatures are used to take the ways of inertia part and the delay part to simulate the operation of diesel engines, and they consider output power of diesel engines is a function of throttle position rack, while they have ignored the impact of the speed of diesel engine group output.Therefore, this article gives a more accurate diesel engine model, that the output power of diesel engine is dual function of the throttle position and speed rack. The article has taken both analysis and simulation studies for the model and it has carried out to verify the validity of the model.Based on the above simulation model, this paper has analyzed instantaneous frequency and the generator terminal voltage changes by adjusting the acceleration and deceleration rate at different loads, and then in order to meet the requirement of "steel vessel rules" to arrive at the final program of crane acceleration and deceleration rate, and draw out the crane acceleration and deceleration rate curve.Using regression analysis, the acceleration and deceleration rates point of the crane will become synthetic function, in the controller,which can change acceleration and deceleration rate of inverter based on the function dynamically.The traditional crane acceleration and deceleration rate is a fixed value, which will take the crane's operating speed as the expense. In this paper, the crane acceleration and deceleration rate limiting scheme achieve the speed smoothly and improve the operating speed of the crane under the premise of that the crane doesn't affect the stable operation of power system.