Study On The Estimation For SOC Of Battery In Synergic Electric Power Supply System On HEV

Nowadays auto industry has become one of the main parts of industrial energy consumption, Therefore, many automotive company are researching the auto energy-saving technology. HEV has been acceptable by the market as the most competing product , because it pay the smaller increase in costs for significant fuel economy and emissions performanceThe problem of HEV electricity storage system in the actual development process has become more apparent. This major problem is the battery SOC accurate estimation. Battery SOC value of Hybrid Vehicle is one of the most important parameters in Control Strategy. To some extent it determines the engine power distribution, We can say that the accurate estimation of SOC determines the HEV energy saving performance. However, due to the battery highly nonlinear property, Battery SOC can be estimated only by measuring the number of external battery parameters by calculating indirect access. Moreover, the hybrid electric vehicle batteries work situation is more complex, there are many short-term high current charges and discharges. The complex conditions also lead the estimation of SOC more difficult.Super capacitor brings new solution for SOC estimation This is because the super capacitor significantly reduce the working pressure of battery This has not only greatly extend the battery life, but also bring a new idea of. accurate estimates ofbattery SOC FAW "JieFang" brand hybrid city bus batteries group has met the estimation of SOC value, so it is necessary to develop a new method to estimate the battery of SOC in Synergic Electric Power Supply System.Firstly, this paper analysis nickel-hydrogen batteries from the basic characteristics, then Analysis the working situation of battery in Synergic Electric Power Supply System .According to the characteristics of working situation it made a compensation SOC estimation method..Secondly, analysis by the standard charge method for the nickel-hydrogen battery, according to actual situation developed a practical and effective charge-discharge method.. Through the analysis of charging method, develop a accurate way to make battery to a SOC state, get the relationship between the stable voltage and SOC.Thirdly, analysis charge-discharge efficiency characteristics. Under the different battery charge and discharge current. Then through experiment get the battery SOC0.5-0.7 charging and discharging efficiency. in the different currents . Under the current experimental conditions carry on the experiment of the battery life cycle.Last, According to the experimental data and combine the composite Power Battery charge and discharge characteristics, established the mathematical model of Battery SOC estimation.. Established the Synergic Electric Power Supply System test bench, and design the battery working cycle for a variety of experimental conditions. then the certificate the accuracy of SOC model .The results showed that the accuracy of the method of Battery SOC estimation is above 94%, reached the requirement of hybrid electric vehicle battery SOC estimation...