Research On Thrustallocationmethodof Dynamic Position System Combined With Power Management

People's further development and utilization of marine resources makes dynamic positioning ships been used widely,simultaneously,putting forward higher requirements for the performance of the dynamic positioning system.Thrust allocation,at the end of the dynamic positioning system,assigns thrust command to each propeller according to certain logic strategy,which plays an important role in the accuracy and flexibility of the ship positioning.However,the traditional thrust allocation mainly aimed at the minimum power consumption of the thrust system,does not take into account the impact of change in the power consumption of other electrical equipment on the power grid,which may cause serious consequences such as loss of power.In this paper,the dynamic positioning ship with full electric propulsion is taken as the research object,and the propulsion system and the thrust allocation algorithm are used to assist the power management of the power system,in order to reduce the power consumption fluctuation of power grid and improve the stability of the whole power system.The main work is as follows:For the research on thrust allocation method based on power management,firstly,the paper discusses the function modules and related control strategies of power management system,and completes the modeling of propulsion system of the dynamic positioning.After that,on the basis of propulsion system model,according to the principle of thrust allocation,modeling of optimal thrust allocation is finished by building the model of the thrust structure of ship hull and constraint condition.In order to solve the problem of thrust allocation,the paper introduces two kinds of optimization algorithm,sequential quadratic programming and Lagrange multiplier method,and improves the multiplier method.Then,based on the thrust allocation model,the simulation experiments are carried out,and the two algorithms are used respectively to simulate the thrust allocation of the ship.In addition,the two algorithms are proved to be able to accomplish the positioning task well by analyzing the simulation results.Finally,according to the results,the advantages and disadvantages of the two algorithms are analyzed and compared.In order to assist the power management of power system to reduce the fluctuation of power consumption in power system,the thrust allocation strategy based on dynamic load control method is adopted.The model of dynamic load control method is built based on two kinds of control modes respectively,and thrust allocation simulation experiments are carried out respectively by using the two modes of dynamic load control method in the light of two kinds of power consumption fluctuation.The analysis of the simulation results show that the two kinds of control modes of the proposed method can achieve the goal of positioning and reduce the power consumption fluctuation of power grid simultaneously.In the end,the advantages and disadvantages of the two control modes are analyzed according to the control effect.