Research On The Fuzzy Control And Optimization Of Synergic Electric Power System On Vehicle

With energy shortage and environmental degradation problems getting increasingly serious, the development of new vehicles is attracting more and more attention from governments and automobile industry. Under this background, electric vehicles have been rapid development, brings automobile industry into the era of "energy saving, emission reduction". Hybrid vehicles on the basis of the existing engine, equipped with a motor/generator, technology is mature, becomed one important direction of electric vehicles’development. Hybrid electric vehicles require an energy storage system to provide high power and great energy, and the present, the characteristics of the power batteries and ultracapacitors are unable alone to satisfy those requirements under the economy conditions; consider combining them to form a hybrid power system, through rational structure and control strategy, to play the advantages of both devices in the hybrid energy storage system, to break through the single storage device’s technological defects. Ensure that meet the performance needs of the vehicle, at the same time, to achieve greater power efficiency, and extend the service life of complex power, which is the starting point of this paper.This paper firstly analyzed the performance and characteristics of current widely used power energy storage devices, according to the specific working environment, compared the performance of their respective advantages and disadvantages, chosen lithium power battery and ultracapacitor for energy components, their characteristics of discharge and charge, storage, resistance are analyzed in detail. Discussed four kinds of typical complex power structure, selected the vehicle complex power structure using ultracapacitor and DC/DC converter in series and parallel with the lithium power battery. Charge and discharge state of complex power system are generalized from the operating modes of the parallel hybrid electric vehicles.Then the power distribution model of the hybrid power system was established and analyzed. The power distribution factor was as a control object, to establish management strategy of complex power system which based on fuzzy logic, due to the strategies of discharge and charge are different, designed two fuzzy logic controllers. The model of complex power has been completed in the ADVISOR, then been simulated, the simulation results of fuzzy logic control strategies are analyzed. On the basis of the results in the above, the membership function’s parameters of the power distribution factor act optimized object, the fuel consumption ratio and regenerative braking energy recovery ratio act optimized target, established optimization mathematical model of energy control strategies, the genetic and ant colony algorithm was used to optimize.Simulation results show that optimized fuzzy control strategies can more effectively reduce the fuel consumption ratio and improve the regenerative braking energy recovery ratio. That mean the super capacitor’s role of "push and pull" has been strengthened, the lithium battery has been better protected, while improving the complex power efficiency and extending the life of system.