Research And Implementation On Charge-Discharge Modules And The Parallel Current-Sharing Technology Of High-Power Battery

The current society faces the double pressure of nervous petroleum resources and serious environmental pollution, it is an urgent need to develop new energy. Many countries are scrambling to join to the ranks of developing the electric car industry to meet the dilemma of the shortage of future power energy. As the core part of the electric vehicle power supply, the performance of power battery is directly related to the performance of electric vehicles. Meanwhile as a kind of new energy which meets the development needs of low carbon economy, has a broad application prospect in the future. So it is very meaningful that testing the performance of power battery. At present domestic battery test equipment are widespread small capacity, low precision, poor reliability, therefore it is important to study high power, high precision, high efficiency battery test equipment. This paper mainly researchs two parts of works on this background: design and implementation of the charge-discharge module of high-power power battery and the current-sharing control scheme of modules in parallel. Specific work content is as follows:1. Aim at the shortcomings of existing battery test system and combining with the job requirements of the high-power power battery test system, overall design of charge and discharge modules is completed, including the design of charge-discharge module scheme and current-sharing scheme in parallel.2. The common topology structure and working principle of isolated DC/DC converter is studied, according to the performance requirements of the test system, the full bridge converter is selected as the main circuit of charge-discharge module. Using Matlab/Simulink software, the model of the charge-discharge modules in three work modes which are charge with constant current, charge with constant voltage, discharge with constant current is established and the simulation results are analyzed. Based on that the design of main circuit and the selection and production of related components is completed, the peripheral control circuit is built with the main circuits as the core,including the main control circuit, drive circuit, signal detection circuit, protection circuit and switch control circuit.3. The advantages and disadvantages of traditional current-sharing scheme in parallel are analyzed and combining with the overall characteristics of the test systemand the charge-discharge module, a kind of average current flow scheme based on CAN bus is put forward. The circuit model with parallel module in all kinds of work modes is established and simulation analysis was carried on. A flow control panel based on CAN bus communication is designed to complete the flow work between modules. The scheme which gives consideration to the advantage of the digital flow method and average current flow method, is featured by strong anti-interference, high flow precision and well solve the problems of the current imbalance between charge-discharge modules.4. Power battery test platform is bulit and the test and analysis of charge-discharge module and parallel module in various work models is completed, the experimental results show that the charge-discharge modules and module in parallel can meet all the performance index requirements.