Parameter Matching And Performance Optimization Of A Pure Electric Bus Power System

The rapid development of the automotive industry has brought many environmental problems.At the same time,as the price of oil continues to rise,the cost of using automobiles has also increased.The development of pure electric vehicles has become an effective way to solve these problems.Compared with traditional fuel vehicles,pure electric vehicles have the characteristics of low noise,no pollution,and high energy utilization.Especially for pure electric passenger cars,the internal space is large,and the average speed of driving is relatively low.Therefore,the power battery with a large volume and a large number can be placed inside,and the driving range is relatively long,and has a broad market.Application prospects.Power system parameter matching is an important part of the pure electric bus in the design and development process,and the matching result will directly affect the power and economy of the whole vehicle.In this paper,a pure electric bus developed by a car company is taken as the research object.According to the performance requirements of the design,the main components of the power system are selected and matched,and the parameters of the powertrain are optimized by genetic algorithm.The main contents are as followsFirstly,the basic structure and layout of pure electric bus are introduced.The dynamics analysis of pure electric bus is carried out by using the principle of automobile kinematics.The dynamic performance and economic performance of pure electric bus are analyzed.According to the basic parameters and performance requirements of the vehicle,the power battery,drive motor and transmission system are analyzed and selected,and their parameters are determined through detailed calculation.Then use the CRUISE software platform to build a pure electric bus simulation model and set calculation tasks such as acceleration performance,climbing performance and endurance performance,and calculate these tasks.After analyzing the results of the simulation calculation,it is found that the performance of the vehicle meets the requirements of the expected performance index,but there is room for optimization.In order to improve economic performance under the condition of ensuring vehicle dynamics,NSGA-II improved multi-objective genetic algorithm was selected to optimize the transmission system.CRUISE and ISIGHT software were used to establish a joint simulation optimization platform to find the most accurate ratio of the final speed reducer in the feasible domain.Excellent solution.The optimized main reducer speed ratio value is substituted into the completed vehicle simulation model for simulation.Compared with the pre-optimization simulation results,the maximum climb grade of the vehicle is increased by 1.76%,and the 40km/h constant speed driving range is increased by 8.06%,0-50km/h acceleration time reduced by 3.08%,other aspects of the results are also in line with vehicle performance indicators.Finally,the pure electric bus prototype is tested for the dynamics and economy of the vehicle in accordance with the test standards and methods stipulated by the national standards.The test results show that the economy and dynamics of the vehicle can meet the performance requirements of the design,and the difference between the experimental results and the simulation results is small.The feasibility and rationality of the parameter matching of the pure electric bus power system and the optimization of the transmission ratio are verified.