Simulation Study On Electric Propulsion And Manoeuvring System Of Inland River Pure Electric Ship Under Different Working Conditions

With the deepening of the national "dual carbon" goal,it has greatly promoted the urgency and enthusiasm of carbon reduction in China’s river transportation industry.With the rapid development of inland pure electric ships in recent years,this ship has the characteristics of zero noise,zero emissions,and high efficiency,which is bound to become the future direction of green ship development.As the core of ships,the electric propulsion system and control system of ships have been developed early in Western countries,mainly in Northern Europe.However,there is relatively little simulation research and investment in this field in China.This article establishes a simulation model for the electric propulsion system and control system of pure electric ships,and analyzes the performance changes of the electric propulsion system and control system of ships under different working conditions,It has practical significance for ship navigation guidance and ship design.This article is based on the "Navigation Star",the first inland pure battery ship in Harbin,and analyzes the composition and operating principles of each subsystem in the ship’s electric propulsion system.The relationships and parameters between each subsystem are determined,and simulation models of each subsystem are established in Simulink.A dual closed-loop control model for DC converters was established based on the charging and discharging characteristics of lithium battery packs.The direct torque control method for motors was analyzed,and a motor control model was established.Subsequently,a ship three degree of freedom maneuverability model was established based on MMG modeling ideas,and a ship wind load calculation model was established through empirical formulas and numerical calculation methods.Finally,the accuracy of establishing models for the electric propulsion system and control system was verified by comparing simulation and experimental values of parameters at different propulsion motor speeds.Based on the composition and principles of the electric propulsion system and control system,the relationship between the two was established,and an integrated simulation model of the electric propulsion system and control system of the inland waterway ship was built in Simulink.Through this model,the simulation of ships under different working conditions was conducted.Firstly,the simulation of ships linearly accelerating from the design working condition to the maximum speed was conducted.The simulation results showed that the fluctuation value generated by the acceleration method system was small,which met the requirements of inland river sightseeing ships.Secondly,ship rotation and Z-shaped rotation simulations were conducted,and the results showed that the ship had good maneuverability and met IMO international standards.And by comparing the impact of sudden changes in the deviation angle of the pod thruster and slow increase changes on the ship’s rotation,and analyzing the changes in simulation parameters in the two changes,the results indicate that ships operating in inland rivers are more suitable to use slow change methods for reverse transfer.Finally,the impact of wind power levels 0-4 on ships was analyzed through a model,and the relationship between wind resistance,ship power,ship speed,wind power level,and wind direction angle was summarized through simulation results.In summary,this article introduces a simulation method for the electric propulsion system and control system of inland pure electric ships,which can simulate the performance of inland pure electric ships under different working conditions.