Research On Energy Management And Energy Saving Of Ship Parallel Gas-electric Hybrid System

With the increasingly stringent emission regulations of the shipping industry and the expansion of the emission control area,the traditional propulsion system with diesel engine as the core is difficult to improve the system efficiency and meet the increasingly stringent emission standards.The ship hybrid power system makes full use of the advantages of multienergy,by adopting clean fuels and optimized matching of the engine over the full load range,so the engine can always work in the high efficiency zone,effectively improving system efficiency and significantly reducing emissions.This paper proposes a ship parallel gas-electric hybrid power system,which studies the key technologies such as system design selection,matching optimization and energy management strategy design,and provides theoretical basis for the engineering application of the system.Firstly,the concept design of the overall scheme of the system is carried out,a scheme of ship parallel gas-electric hybrid system is proposed,and the matching and selection of the applicable ship type for the system is carried out.Then,the simulation model of the system is established on the Simulink platform,which mainly includes the gas engine model,permanent magnet synchronous reversible motor model in motor mode and generator mode,lithium iron phosphate battery group model,simplified clutch and gearbox model,propeller model,power transformation device model,power distribution controller model and energy management strategy model,etc.Secondly,according to the operation characteristics of the ship hybrid power system,the cycle conditions suitable for the system research are selected,and the operation cycle of the ship is designed with the port tugboat as an example.The average storage efficiency of the battery in the system is calculated,and the energy flow of the system under different propulsion modes is analyzed.The mechanical propulsion,electric propulsion and energy storage power propulsion efficiency and sensitivity,total propulsion efficiency and improvement of the system under different working conditions and different power ratios are studied.The results show that the total propulsion efficiency of the system decreases under the condition of high load and rotational speed,but the total propulsion efficiency increases with the decrease of load and rotational speed,and the greater the total propulsion efficiency when the load and rotational speed are lower.Finally,an energy management strategy based on logical threshold is designed for the system,and the equivalent energy consumption optimal algorithm is used to optimize the logic threshold boundary,and the energy management strategy flow chart is drawn.The energy efficiency and energy saving rate of the system under different working conditions and different degrees of hybridization are studied,and the actual energy-saving effect of the system is evaluated by taking the port tugboat as an example.The results show that the degrees of hybridization of the system is better than 0.25,and the comprehensive energy saving effect and comprehensive performance are better when the degrees of hybridization of the system is 0.25~0.35.The conclusions obtained in this paper can provide theoretical basis for the design selection,matching optimization and energy management strategy of ship parallel gas-electric hybrid power system.