Research On State-of-Charge Estimation For Battery Of Electric Underwater Vehicles

With the development of Marine resources,underwater vehicle can carry out various underwater tasks,and its importance is increasingly apparent.The electric power underwater vehicle with its low noise operation,almost no track,the vehicle performance is almost free from the impact of other advantages depth voyage,becoming the trend.As the main energy storage device of electric power underwater vehicle,the research on the battery development and monitoring becomes more and more urgent.The State of Charge(SOC)is a very important parameter for the underwater vehicle battery,and it is exact estimated that the underwater vehicle can successfully complete the precondition and guarantee of the given task.In order to estimate the battery charge of state of the electric underwater vehicle,the following work is mainly carried out in this paper:(1)Battery test system is used for charging and discharging cycle test of electric power underwater vehicle battery.The experimental results show that the internal resistance,working voltage and other parameters of the battery are consistent with the different charge-discharge rate trend.In this paper,the influence of the external environment on the battery SOC of the electric underwater vehicle is studied,and the dynamic hysteresis characteristics of the battery are found in the experiment.(2)Based on the dynamic hysteresis characteristics of the battery of the electric power underwater vehicle,a modified open-circuit voltage method was proposed to estimate the SOC of the battery of the electrodynamic underwater vehicle in the static state.Using traditional open circuit voltage method for electric power underwater vehicle to estimate the SOC of the battery,need to rest after a period of time to measure the open circuit voltage of battery,the length of incubation time will directly affect the electric battery charged underwater vehicle state estimation accuracy.In this paper,through the establishment of electric power underwater vehicle battery and the second-order circuit model,using the test data,the cell incubation time,open circuit voltage and the relationship between the battery SOC and fitting,estimates of the modified open circuit voltage method was proposed for electric power underwater vehicle SOC of the battery.(3)For the rise of intelligent computing method,in order to realize electric power underwater vehicle battery SOC online estimation,based on electric power underwater vehicle battery voltage change at work,neural network was established in this paper to explore the relationship between the working voltage and the battery SOC.Charging and discharging rate of underwater vehicles affecte the SOC of batteries,in order to make the neural network model accurately monitoring electric power underwater vehicle battery SOC,this paper established three neural network model for estimating the specific discharge ratio in SOC of the battery,through the training and simulation test data,the estimation errors are kept within 5%.In this paper,the modified open circuit voltage method makes up for the traditional open circuit voltage method in estimating the battery SOC need to stand for a long time,at the same time,neural network and can realize constantly online battery SOC estimation,this achievements have a positive effect for the development of BMS technology.