Research On Transient Process Optimization Control Of Marine Gas-Electric Hybrid Power System

In recent years,the combination of single engine and other power forms to form Marine hybrid power system has become an effective means of energy saving and emission reduction.Using hybrid power to combine power sources under different operating conditions to form different operating modes can effectively improve ship energy efficiency and reduce emissions.However,when the hybrid power system switches between different working modes,it is difficult to maintain the stability and continuity of power transmission in the hybrid power system control.This paper studies how to coordinate the gas engine and motor in the mode switching process of parallel Marine gas-electric hybrid power system.The research work mainly includes the following aspects:This paper firstly introduces the research of ship gas-electric hybrid system architecture,on the basis of using the simulation software of the system included in the equipment and parts based on the principle of simulation modeling,which mainly include gas engine,permanent magnet synchronous motor,clutch,gear box and power battery and other equipment.Because this paper mainly studies the mode switching of gas-electric hybrid system,the dynamic characteristics of gas engine and permanent magnet synchronous motor are simulated and analyzed based on the modeling work.Then the necessity of dynamic coordination of ship hybrid mode switching is analyzed,and the mode switching rules of gas-electric hybrid system are designed.In view of the system mode switching process,the structure of the hybrid power system is transformed first,and the state equations of the system under different states are obtained.After that,the parameters affecting mode switching of hybrid power system are determined as motor target torque and clutch binding pressure through simulation experiment analysis,and the evaluation function of mode switching process is constructed,which includes three evaluation indexes:gas engine speed fluctuation,transmission shaft impact and clutch friction work.Then,the whale optimization algorithm is proposed to optimize the control parameters by calling the ship gas-electric hybrid system model to minimize the evaluation function value,so as to optimize the switching process.Finally,according to the designed mode switching condition of hybrid power system,offline simulation experiment is carried out to verify.The results show that,compared with no optimized control,both the speed fluctuation of gas engine and the working condition of transmission system are improved obviously after optimized control.Finally,a semi-physical simulation platform is built to verify the designed control strategy.NICompactRIO is used as system controller and NI chassis is used as real-time simulator for experiments.Experimental results in the semi-physical simulation environment show that the mode switching process optimized for motor target torque and clutch combined pressure can effectively suppress the speed fluctuation of the gas engine,reduce the friction work in the clutch sliding process,and improve the working condition of the transmission system.It shows that the dynamic coordinated control strategy designed in this paper can effectively improve the problems existing in the mode switching process of Marine gas-electric hybrid system.