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Research On Distributed Drive Control System Of Four-wheel Drive Electric Vehicle

Posted on:2021-05-19Degree:MasterType:Thesis
Country:ChinaCandidate:J Z ZanFull Text:PDF
GTID:2392330611957553Subject:Control engineering
Abstract/Summary:PDF Full Text Request
Compared with most electric vehicles that use centralized driving,the four-wheel drive electric vehicle has a simple and powerful body structure,which makes it more congenital in terms of transmission efficiency,power controllability,energy utilization,and driving intelligence.Due to the existence of mechanical transmission shafts and mechanical differentials,traditional electric vehicles not only increase the weight of the vehicle,but also limit the attitude of the vehicle and the process of driving intelligence.Therefore,the research and development of distributed drive control strategies and system design for wheel-driven electric vehicles are becoming more and more important.How to develop advanced control systems and control algorithms to make car power control more precise,car operation safer,and car driving more energy-saving has become the current Research hotspots.This article studies the core part of the vehicle's distributed control system based on the four-wheel drive electric vehicle's power model and control requirements.Aiming at the multi-operating environment problems faced by automobile driving,a driving force distribution algorithm that can switch modes is designed by analyzing the characteristics of the human-vehicle road model,so that the vehicle can drive smoothly in various environments.Aiming at the chattering and pulsation of permanent magnet hub motor,an optimized motor speed regulation algorithm is proposed by analyzing the characteristics and causes of motor vibration.That is,Space Vector Pulse Width Modulation(Space Vector Pulse Width Modulation)flexible speed regulation algorithm,the algorithm is optimized for torque ripple.The research work of this article is as follows:First,based on the vehicle dynamics theory,a characteristic model that conforms to the wheel-type electric vehicle is derived and simplified.By simplifying the traditional mechanical vehicle mechanical model,the reference model is closer to the wheel-driven electric vehicle model studied in this paper.Establish the road model to be tested and the driver model in accordance with the rules of electric vehicle operation and complete the model building in Car Sim software.Secondly,the layered theory is used to build the control system of the vehicle.The upper layer is the driving force distribution layer,and the lower layer is the drive speed control layer.Aiming at the problem of driving force distribution under complex and changing road conditions,a driving force distribution scheme that can be switched with the change of the road feature model is proposed.A driving force multi-modal distributor is designed according to the theoretical scheme.And verify the driving force distribution system.Then,the theoretical analysis of the motor body and its control system is carried out to improve the high-speed chattering problem of the motor system.By designing a flexible vector control strategy at the driving force speed control layer of the car body control system,the torque ripple generated by the permanent magnet wheel motor speed regulation is optimized to reduce the amplitude and frequency of the ripple.The flexible vector control model was built through Matlab,and compared with the traditional vector control and direct torque control,the optimization effect of torque ripple was analyzed.Finally,the upper simulation of the distributed drive control system is completed in the Car Sim-Simulink co-simulation environment to verify the control efficiency of the multi-modal drive strategy.Use the fast computing power of DSP28335 to complete the development of the motor controller,and at the same time design the driver board.Then complete the design of the driver program,and carry out the actual measurement of the drive speed regulation layer to verify the reliability of the drive speed control system.
Keywords/Search Tags:In-wheel drive electric vehicle, Hierarchical control, Multi-modal drive force distribution, SVPWM flexible control, DSP motor control
PDF Full Text Request
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