Research On Energy Saving Control Strategy Of Four-wheel Drive Electric Vehicle Based On Urban Drving Cycle

Energy conservation and environmental protection is the core theme of today's automobile development,especially the construction of "ecological civilization" proposed by the Central Committee of the Communist Party of China,which makes automobile pollution in the field of urban transportation become a hot topic of public concern.In this paper,the wheel hub motor four-wheel independent drive electric vehicle as the research object,constructs the road condition of city,puts forward the working conditions for recognition of energy-saving control strategy,carry out the four-wheel independent drive electric vehicle wheel hub motor modeling,simulation,dynamic property test and test validation of platform development,working conditions,the electric car energy saving control has higher academic significance and engineering application value.Taking Shenzhen city as an example,an urban road operating condition construction method based on K-means clustering algorithm is proposed for the city with dense population and urban traffic density indexes,such as population density,vehicle density,and vehicle-per-municipal road area,etc.Autonomous driving method selected time,vehicles,drivers and sampling equipment to carry out the experimental data,the collected data for filtering,such as pretreatment,using principal component analysis(pca)to dimension of characteristic parameters selection,determine the k-means clustering algorithm are three parameters using the data is divided into five categories,reference NEDC condition and WLTC conditions,according to the characteristics of the city population intensive selection based on the clustering center four segments of working condition of congestion and a piece of expressway operating mode of city driving cycle.The deviation analysis shows that this method can effectively solve the problem of constructing the driving condition in the population intensive city.The driving motor test platform and the vehicle dynamics simulation platform are developed.A driving motor characteristic test method based on the driving simulation loading device is proposed.The driving motor test platform developed in this paper is composed of a driving wheel device,a vertical loading device and a signal acquisition device.The motor under test drags the driving wheel device,the vertical loading device simulates the load,and the signal acquisition device collects the experimental data,and then gets the external characteristic parameters and efficiency MAP model of the drive motor after filtering.Then based on testing the dynamic characteristics of the motor parameters and vehicle dynamics parameters,in the AVL CRUISE software developed for urban driving cycle of four-wheel drive electric vehicle simulation platform,in view of the city driving cycle on the platform in the form of two drive and four-wheel drive simulation and analysis of energy consumption choice under typical working pieces more energy-efficient drive form,for saving energy control strategy to lay the foundation.A hierarchical energy saving control strategy for condition identification based on genetic K-mean clustering algorithm is proposed.The control strategy includes two drive/all-wheel-drive vehicle on architecture form selection and motor torque distribution layer two levels,including vehicle secondary drive/all-wheel-drive form choice layer using k-means clustering algorithm are genetic algorithm and its real-time identification data for vehicle is a typical working condition,the typical working condition of the corresponding drive form exists in the controller,the result according to the condition of instant choice more energy-saving drive or four-wheel drive vehicle drive form.When it is necessary to adopt the four-wheel drive,the motor torque distribution layer proposes a four-wheel drive energy saving distribution strategy based on torque optimization of the front and rear motors,which further reduces the vehicle power consumption.The core of the whole layered energy-saving control strategy is to ensure that the motor works in the high-efficiency area during the driving process of the vehicle.By identifying the driving condition of the vehicle in real time,the energy-saving driving form can be quickly selected.This strategy has high efficiency and obvious energy-saving effect.A test platform for wireline four-wheel drive electric vehicle with independent intellectual property rights is designed and manufactured.The overall scheme,hardware,software,communication and drive control system of the test platform are introduced in detail.With the shenzhen road condition data,based on the equivalent condition of clustering center parameters is put forward a kind of test method,the test method of equivalent condition by uniform acceleration,uniform section,uniformly retarded and idle speed and so on,the main component of equivalent condition parameters and the working condition of building the same clustering center,this paper to ensure that the equivalent condition of the main characteristics in accordance with the working condition of building.The test platform of electric vehicle was carried out on the chassis dynamometer,which proved that the equivalent condition test results were consistent with the simulation results and verified the effectiveness of the equivalent condition test method.