Real-time Simulation Research On Energy Management Strategy For All-electric Propulsion Gas-electric Hybrid Ships

The green development of ships has become an inevitable trend in the development of shipping industry,and the application of hybrid power,electrification technology and the use of clean energy is an effective way to realize energy saving and emission reduction of ships.LNG as a ship fuel has the advantages of high storage efficiency and good environmental performance,and has a broad development prospect.The natural gas engine applied to inland ships will have high gas consumption and poor dynamic response due to the drastic changes of ship load,as inland ships have variable sailing conditions and high maneuverability requirements.With the continuous development of battery energy storage technology,marine natural gas engine combined with power battery constitutes gas-electric hybrid ship and improves the energy efficiency of system operation with powerful energy timing regulation ability of power battery,which becomes an important way to realize green shipping.Compared with the single energy structure,the hybrid power system is more complex,and how to take into account the system stability,economy and environmental protection and other objectives has become a research hotspot in the field of green ships,this paper takes the all-electric propulsion gas-electric hybrid inland ships as the object,and carries out the following research on the energy management strategy of the hybrid power system.Firstly,for the gas-electric hybrid power system of all-electric propulsion ship,following the modeling process from component to system,theoretical analysis,simulation modeling and numerical calculation are used to model the natural gas power generation system,power battery system and load,etc.For the natural gas engine,the simulation model is built in GT-Power to obtain the gas consumption rate curve and universal characteristic curve of the natural gas engine;based on the inverse control rules of the Energetic Macroscopic Representation method,the simulation and verification platform architecture of the energy management strategy of the gas-electric hybrid power system of all-electric propulsion ship is constructed to lay the foundation for the subsequent research of the energy management strategy.Then,the energy management strategy based on dynamic programming is used to manage energy to the gas-electric hybrid power system with typical power demand,and the optimal energy management results under global optimization are obtained for the comparison reference of energy management strategies based on determining rules and model predictive control;The energy management strategy based on the determining rules is designed based on the principle that the natural gas engine works in the efficient gas consumption rate interval,the power battery bears the high frequency part of power fluctuation,and the natural gas engine bears the low frequency part;The energy management strategy based on model predictive control is designed with the objective function of minimizing gas consumption of natural gas engine,and the objective function solution problem is transformed into a quadratic programming problem,and the method of objective function solution is analyzed.Finally,the Energetic Macroscopic Representation method and Simulink-Simscape Power Systems modeling method are selected for offline simulation to verify the effectiveness of the Energetic Macroscopic Representation method and compare the efficiency of the two simulation methods;for the two energy management strategies,a real-time simulation platform is built based on Speedgoat to verify the efficiency of the two energy management strategies.In this paper,we propose to model the system with the Energetic Macroscopic Representation method,combine the inverse control rules of the Energetic Macroscopic Representation method,design the energy management strategy of the hybrid power system,and build a real-time simulation verification platform based on Speedgoat to verify the effectiveness of the proposed method.On the basis of achieving the design objectives,the simulation time of the energy macro description modeling method is reduced by 94.78% compared with the Simscape Power Systems modeling method at the same simulation step;under the energy management strategy based on the model predictive control,the whole-ship gas consumption is reduced by5.83% compared with the energy management strategy with deterministic rules.