Design Of High Efficiency Multichannel Battery Capacity Test System

In recent years,with the development of power generation equipment,renewable resources such as wind power,water conservancy,solar energy and tidal energy have replaced traditional firepower.Electric energy has become a truly clean energy source and has played an important role in the development of new energy.The promotion of electrical equipment has promoted the widespread use of lithium-ion batteries.Different industries have different battery performance requirements.Step-by-step reuse of lithium batteries can extend battery life and maximize battery value to reduce battery cost.In order to fully utilize the battery performance and ensure the consistency of performance when using the battery,it is urgent to develop an efficient,accurate,energy-saving and simple battery capacity test system.It can calibrate and screen the actual capacity of the lithium battery.In response to this problem,the paper designed a battery capacity test system based on parallel bidirectional Cuk converter.The test system could complete the test of multiple cell test channels at the same time,and the energy transfer between the channels was preferentially transferred to the charging channel through the mutual transfer of energy between the channels.This test system enabled efficient,energy-saving test requirements for battery test systems.The main contributions of the thesis are as follows:(1)The paper studied the charging and discharging characteristics of lithium batteries during battery capacity testing.According to the characteristics of the inverter parallel method,the energy of the battery discharge was preferentially used to charge other channels,thereby realizing energy recovery during the battery capacity test.According to functional requirements,the system was divided into power supply module,main control module,man-machine interaction module,converter module,detection module and communication module.(2)Aiming at the system charge and discharge test control,the paper studied the working principle of the converter module.Combined with the constant current-constant voltage charging,constant current discharge strategy and input and output characteristics of the converter,the energy flow state space model and small signal model in the parallel converter circuit were established,and the constraints of the variables in the model were given.The principle of constant current control,constant voltage control and overflow energy absorption control of the system battery was analyzed.The PI controller was designed to achieve accurate and stable control of battery charge and discharge.(3)Taking the battery capacity test system prototype,the host computer of the prototype realized human-computer interaction and battery capacity calculation,and the lower computer realized real-time control of battery constant current-constant voltage charging and constant current discharge.The performance of the prototype is tested by experiments.The prototype test results showed that the system can accurately and stably completed the current control,voltage control and overflow energy absorption control during the test of the battery capacity test system.It can transfer energy among many test channels and realize efficient utilization of test system energy.