Research Onactive Equalization And Protection Strategy For Batteries Of Strong Mixing Hybrid Electric Car

The hybrid vehicles develop quickly because of the advantage of energy saving and environmental protection. In the first 20 years of the 21th century, the strong mixing HEV will be the main research direction. As the key component of hybrid electric vehicle, power batteries have a significant impact of the HEV, such as the dynamical performance, security and economy. Therefore, in-depth research on battery management has the great significance and engineering application value for improving the performance of hybrid vehicles, guaranteeing the safety of the batteries, prolonging battery lifetime.Firstly, this article analyzes the demands of power batteries for strong mixing HEV, as well as the lithium-ion battery indicators in the national 863 project, researches the equivalent circuit models of battery, analyzes the reason why the inconformity come into being, builds a math module to describe the inconformity of batteries.The voltage of one battery cell is only about 3.3V, so hybrid electric vehicle uses a number of single cells connected in series. Due to factors such as the existence of manufacturing error, the batteries have inconformity in internal resistance, voltage, capacity, and other parameters. So this article specifically designed an equalization circuit which base on the idea of "low charge and high discharge". Then an active equalization control strategy, which is based on the T-S fuzzy theory and aim to enhance the conformity of the cells, has been raised. Besides the equalization, a SOC corrected strategy based on special conditions has been raised.Strong mixing HEV always works in severe working condition, so this article researched an active protection scheme, which include the cell protection strategy based on dynamic diagnosis, the insulation monitoring and High-voltage electric management strategy, the active thermal protection strategy based on Temperature prediction model.To fulfill the demand of simulating work condition test and real vehicle test,a human-machinery software have been designed based on Labview. It can acquire and save real time parameters for batteries. Then the equalization test has been designed and completed.Results show that the equalization project is practical and reliable. The batteries inconformity has been well controlled, and the usability of the batteries has been enhanced effectively.