Research On Driving Cycle And Energy Control Strategy For Pure Electric Buses In Hefei

The extensive use of internal combustion engine vehicle brought several problems, such as excessive consumption of non-renewable energy, huge environment pollution and traffic congestion. The solutions are to develop new energy vehicles and advocate use green public transport. The related ministries have already issued policies which encourage the development of new energy public transportation.The policies are supported by each enterprise and achieved good results in our country.At present, the control strategy of pure electric bus energy storage system has two problems: First, the formulation of control strategy is built on the basis of the standard driving cycle, but domestic and international research shows that national standards and the actual driving cycle are quite different, especially the pure electric bus driving cycle. There are cannot serve as the main basis for strategy formulation. Therefore, it is necessary to establish a set of pure electric bus driving cycle. Second, the traditional logic threshold control strategy exist some questions, such as frequent moves, poor stability condition. So we need to optimize and create a new control strategy for improving the control performance of the traditional logic threshold.To address these two problems, the paper relies on country 863 financing projects which "environment and driving cycle differences and new energy technology research in Hefei". We will study the following contents.1. Driving cycle for pure electric bus is to study in Hefei. The data is from pure electric vehicle demonstration project in Hefei. We obtain vehicle running laws through analysis statistical and get three typical driving cycle module by using principal component and clustering analysis awful-sounding. Hefei pure electric buses driving cycle circulation (HF-PEB-DC) synthesized form these analyses. The circulation conform the pure electric bus actual operation situation and provide the reference for medium-sized city. At the same time, it also provides the basis for the foundation of driving cycle identification and control strategy.2. Research on self-recognition system of driving cycle. After established driving cycle for pure electric buses in Hefei, the driving cycle recognition system has designed by fuzzy control theory. The fuzzy controller input use the pause time rate of driving stages and average speed and acceleration. The output use pure electric buses driving cycle typical module parameters in Hefei. We pose system control strategy and make each language variable assignment table and fuzzy status table and using Simulink build a simulation model. The simulation results show that the original random and uncertain condition has been converted to typical driving cycle which accorded with the module features. It is proved that the development of pure electric buses driving cycle since recognition system is feasible. The identification of driving cycle parameters is used as threshold of the new logic threshold control strategy for the energy storage system.3. Study on mixed energy storage system control strategy. Common control strategies contain traditional logic threshold and fuzzy logic and dynamic programming. Through comparison their advantages and disadvantages, the paper proposes an average rate constraint plus super capacitor state of charge (SOC) constraint for the threshold of a new logic threshold control strategy. This control strategy has several advantages. However, it also has the further optimization. This paper presents a variational method based on the classical vehicle energy storage system. The lowest rate of energy loss in the optimal control ideas is for the mixed energy storage system. This provides a post-optimization research.4. Simulation shows that the control strategy formulation is reasonable. The mixture energy storage system by battery and supercapacitor can reasonable allocation of power which provided by battery dropped significantly and the peak power provided by the super-capacitors. Regenerative braking energy is absorbed mostly by super-capacitors. The system meets the design objectives. It can improve the performance of pure electric bus.