The Key Techniques Of Lithium Battery Energy Storage System

The energy storage system is very important to the electric system.However,some energy storage methods,like flywheel energy storage,compressed air energy storage and so on,have some disadvantages,so these methods can not apply to electric industrial.Compare with those physical methods,chemistry methods have more advantages to energy storage systems.Battery energy storage are being become a researching focous,because it has some significant features.At the moment,Lithium battery energy storage system has many benefits than other battery energy storage sysyem,for example,it would be more flexible in operation,more high in energy density and so on.The dissertation introduces energy storage system’s power converter system and battery management system.In the section one,the dissertation introduces the system’s significance and new status in the world,and researchs the common two-level and the common three-level topology,meanwhile,the writer compares those several topology’s advantages and disadvantages,by the way,the writer discusses PCS power devices’ control.Three-level has some advantanges about AC side input or output and declines the switching frequence.Meanwhile,some three-level topology can apply in high voltage situation.So,three-level topology has obviously been becoming a researching focus.In the dissertation section two,the dissertation improves a method for three-level topology,the new method is simple and effective,at the moment.It is very suitable to DSP programming.First,the method can ensure the power module to work perfectly,second,it obviously reduces complexity of control.In the dissertation section three,the dissertation describes internal current loop control and external loop control to reach some functions which can be used in several situations.In the dissertation section four,the dissertation gives several key technologies.For example,it can result in single or several converters to run in grid or micro grid.In order to prove theories,the writer shows some experiments’ results.About battery management system,in the dissertation section five,the passge introduces BMS’s functions and particularly researchs battery’s SOC estimating and battery balancing.On the one hand,the dissertation gives a simple and accurate method to estimate SOC,on the other hand,the dissertation introduces a new method to blance battery.