Research On A Semi-active Heave Compensation System Combined Variable Frequency With Throttle

Offshore cranes are affected by the heave motion of the ship,which has a negative effect on hoisting.Heave compensation system is essential for the safe and efficient hoisting operation.Semi-active heave compensation system,in which the compensation precision and system energy consumption are taken into account simultaneously,is becoming the focus of research.Because of the frequent movement of the system and the large load,the energy consumption of the semi-active system is still huge.Therefore,it is of great theoretical and practical significance to study the energy saving of the existing semi-active heave compensation system.In order to achieve this goal,a semi-active heave compensation system is designed by combining the valve control system with the variable frequency hydraulic technology.This system not only retains the advantages of the valve control system,such as high control precision,fast response,but also allows full play to the characteristics of variable frequency hydraulic speed control system,which contains large speed range and good energy-saving.In this paper,the design and calculation of the above system is completed.The simulation models of hydraulic system,controller and variable frequency motor are established.The compensation performance is studied.The main research contents and achievements of this paper are as follows:(1)The main parameters of the active heave compensation system are calculated,and some components are selected.The system's severe overflow loss and limited adaptability are found according to modeling and simulation;(2)A semi-active heave compensation system combined variable frequency with throttle is designed and the important components of the system are calculated and selected.A control method combined velocity and displacement compensation is designed to realize the compensation of random wave.The mathematical model of vector induction motor is established based on rotor flux orientation;(3)Both the hydraulic system model and the controller model are established by using AMESim software.The vector variable frequency motor model is established by using Simulink software;(4)Sinusoidal wave and random wave are used as input signals of AMEsim-Simulink joint simulation respectively.The compensation and energy saving effect of the designed system are analyzed by simulation.The energy saving advantage of the system is verified by comparing with the other three systems;(5)In order to verify the performance of the designed system,a simulation test bed,including hydraulic system and whole structure,is designed.