Development Of Backup Power System For AC Steering Gear Of Inland Ship

The water transportation industry is the basic,leading and service industry of economic and social development,and an important part of the comprehensive transportation system in China.Chinese inland transportation industry is booming,and the volume and tonnage of inland ships are constantly increasing.Hydraulic steering gears are widely used due to their advantages of small size,light weight,large torque,and high sensitivity.If the power supply fault occurs in the operation of hydraulic steering gear,it will cause the ship to lose control of the course and cause serious safety problems.In recent years,there have been many accidents involving power supply of ship steering gears in domestic inland transportation,which have caused different degrees of damage to the hull itself,the navigation area and the surrounding ships.Therefore,the research and development of the backup power supply system of inland ships' AC steering gear can effectively prevent the power supply failure of the ship's steering gear,which is very important for the safe and stable operation of inland ships.This paper develops an economical and reliable backup power supply system for inland ships AC steering gears in order to prevent power failures of inland ships AC steering gears.The thesis first analyzes the power supply requirements of the AC steering gear based on the actual operating conditions of inland ships.After comprehensively considering the battery operating characteristics and engineering application costs,the lithium iron phosphate battery is selected as the backup power system battery pack,the battery capacity configuration and system topology design are carried out with the system cost as the goal,and then a detailed analysis of the converter parameter design.Secondly,in order to ensure the safe and stable operation of the backup power system,the thesis carried out modeling analysis and SOC estimation of lithium batteries.Comprehensively considering the accuracy and availability of the model,a second-order RC equivalent circuit is selected for lithium-ion battery modeling and parameter identification,and then based on this,the extended Kalman filter algorithm is used to estimate the SOC of the lithium-ion battery,then using the ampere-hour method as a comparison object,Matlab / simulink simulation is used to verify the effectiveness of the model and algorithm.Third,in order to ensure the timely and effective charge and discharge operation of the backup power system,the converter part was analyzed and modeled in detail,the on-grid and off-grid control strategies of the backup power system are proposed based on the actual working conditions of inland ships.When the ship's main power supply fails,the backup power supply system works in off-grid operation and independently supplies power to the AC steering gear to ensure the controllability of the ship's course.When the main power supply of the ship works normally and the battery pack of the backup power supply system needs to be charged,the system works in the on-grid operation state,and obtains electric energy from the distribution board to charge the battery pack.The effectiveness of the system topology and control strategy is verified by Matlab / simulink simulation.Finally,the device parameter design and selection of the 20 k W backup power system platform are analyzed,which laid the foundation for the construction of the backup power system platform and related experiments.