Study On Matching And Performance Of Diesel-electric Hybrid Power System For Polar Ships

As countries around the world pay more and more attention to polar ecology and resources,it promotes the rapid development of polar shipping and scientific research.Because of the complex navigation environment in polar sea,the power transmission system of polar ships must undergo the test of the frequent changes of polar ice conditions and the large range of load increase and decrease.To solve the above problems,green and energy-saving hybrid systems are more suitable for polar ships.Therefore,this paper takes the polar ship hybrid power system as the research object,studies the system’s matching and selection,model building,energy flow,energy efficiency,energy management strategy,dynamic characteristics and other aspects,and provides theoretical support for the design and research of polar ship hybrid power system.Firstly,a hybrid power system for polar ships was proposed,it has 5 kinds of working mode,and the system was matched and selected in detail,including the ship propeller matching,power,rotate speed matching,and battery matching.The parameters of each component of the system are obtained,on this basis,in the MATLAB/Simulink platform,the use of modular modeling idea,the hybrid power system model of polar ship was established.Secondly,according to the propeller propulsion characteristics,the full load condition of propulsion characteristics was selected to study the energy flow of the system in different working modes,so as to study the energy efficiency of the polar ship hybrid system and pure diesel engine system at different loads and speeds under the design conditions.The results show that the driving efficiency of the hybrid system is greater than that of the pure diesel engine system in a certain range of power ratio except for the high load and high speed conditions.Thirdly,a equivalent consumption management strategy based on particle swarm optimization algorithm was designed.By setting equivalent charge and discharge factors,the SOC penalty function of battery was introduced.Particle swarm optimization(PSO)was used to solve the instantaneous minimum equivalent fuel consumption of the system,and then the optimal equivalent charge and discharge factors were selected.The torque distribution and operating point of diesel engine and reversible motor,SOC change of battery and fuel consumption of diesel engine were studied respectively under polar ice-free and ice-free conditions.The results show that the optimization effect of the minimum equivalent fuel consumption energy management strategy is mainly affected by the conditions without ice and with ice,and the working points of diesel engine and reversible motor are more distributed in the high efficiency region under the conditions with ice.Finally,the dynamic characteristics of polar ship hybrid propulsion system based on logic threshold were studied.A differential tracker module is added to the hybrid power system model of polar ship.The energy management strategy based on the logical threshold was designed,and then the energy management rules were formulated.The energy management strategy model based on the logical threshold was built on the MATLAB/Simulink simulation platform.On this basis,the navigation conditions in the polar sea were designed,and the dynamic characteristics of the polar ship hybrid propulsion system were studied.Research results show that add differential tracker module and logic threshold energy management strategy of polar Marine hybrid system model has good dynamic characteristics and the real-time performance.It can meet the needs of polar condition of load changes frequently,the actual speed and design speed matching is good.