Study On Design And Capacity Optimization Configuration Method Of Dredging Ship Hybrid Energy Storage System

With the development of large-scale ships,the requirements for port berthing capacity and navigation capacity are increasing.Thus dredging ships are particularly important in guaranteeing the water depth to meet the requirements of large ships.Traditional power system of dredging ship is composed of diesel generator sets.However,due to its particularity of frequent load disturbance during operation,the output power of diesel generator sets fluctuates sharply and high power output time makes a very little percentage in total time,the diesel engine works in low efficiency conditions most of the time.Which therefore causes the problem of incomplete fuel combustion and low ship energy efficiency.Aiming at problems above,this paper proposes a solution that combining lithium iron phosphate battery and ultra-capacitor to form a hybrid energy storage system,which stabilizes the fluctuation of the output power of the diesel generator sets and reduces the amplitude to reduce the excessive redundancy of the capacity of the generator sets and makes the generator sets work in optimal-efficiency conditions.This paper takes a dredging ship as research object,starts from the load characteristics of dredging ships,focuses on the analysis and design of the topological structure of hybrid energy storage system,simulates and verifies the optimization method of capacity configuration for hybrid energy storage system under set energy management strategy.The research this paper carried out was below:(1)This paper collects the actual operation data of the dredging ship,and divides the output power of the diesel generator sets into several sections based on the load characteristics.Aiming at the problems that excessive redundancy of current diesel generator sets capacity,great fluctuation of output power and low efficiency of working condition,a method that using energy storage technology to stabilize the fluctuation of diesel generator sets out power is proposed,which is combining Lithium iron phosphate battery and ultra-capacitor to form a hybrid energy storage system according to the characteristics of loads and various energy storage devices.The working principle and charge-discharge characteristics of the battery and ultra-capacitor are also modeled in detail.(2)Based on the topological structure of the hybrid energy storage system designed,this paper establishes the optimization model with the reliability of ship power system as primary condition and the best system economy as purpose,formulates the energy scheduling strategy and optimizes which by adapting the basic particle swarm optimization algorithm and the improved quantum-behaved particle swarm optimization algorithm.Taking typical data as an example,this paper compiles the algorithm program by MATLAB to calculate the optimal configuration capacity of the hybrid energy storage system and the real-time charge and discharge power of the battery and ultra-capacitor under the example is calculated.After comparing the results of the two algorithms,the improved quantum-behavior particle swarm optimization algorithm is proved to be stronger in searching capability.(3)In order to verify the reliability of the optimized configuration method,this paper builds a small-scale semi-physical hybrid energy storage system test bench.According to the ratio of real load of the test bench and the load in the example,the test bench capacity is configured correspondingly.The semi-physical test is carried out with dSPACE as the executing unit of the energy management strategy,and the real-time charge and discharge curves of battery and ultra-capacitor are collected.Comparing which with the simulation results,the results show that the optimal configuration method for the capacity of the hybrid energy storage system is effective and is of certain reliability.