Energy Saving And Comfort Optimization For Electric Bus Based On Longitudinal Dynamics Model

With the development of automotive technology, automobile industry represents the industrialization level and scientific and technological of a country, and has become the pillar of the national economy in developed countries. When promoting social development and bring convenient, fast and comfortable modern life, automobiles also brings a series of social problems. With more and more serious environmental problems and energy crisis, new energy vehicles are developed and become a popularization of choice around the world.This paper analyzes and discusses the comfort and energy efficiency indicators of pure electric passenger car. A pure electric vehicle longitudinal drive model is developed. Driver intent module and optimization algorithms for electric bus based on longitudinal dynamics model are developed. A parameter correction of motor magnetizing inductance and rotor resistance change during operation is made to improve the efficiency of the motor. Hardware and software of the vehicle controller is designed. The optimal control strategy is achieved by the vehicle controller and in real pure electric car made experimental verification. The main work of this paper is:(1) Base on the definition of comfort and energy efficiency of pure electric vehicle, international and domestic research evaluation on comfort and energy efficiency of vehicles is proposed for pure electric vehicle comfort and energy efficiency targets. The index combines international and domestic comfort and energy efficiency research for new energy vehicles, can well responses the driver and passenger’s comfort and energy efficiency requirements of pure electric passenger car, have certain significance for new energy vehicles comfort and energy efficiency studies have certain significance.(2) According to the structure and physical principles, a model consist of subsystems of electric vehicle is developed, then a nonlinear input-output model is established. Data collected through the CAN bus from vehicle, the pure electric bus model was verified. Nonlinear output value and the actual value of the model error is less than1.08%of the input, the fitting effect is good.(3) Energy saving and comfort optimization strategy based on NMPC(NMPCESCOP) is proposed. The control strategy includes driver intention module and nonlinear predictive control algorithms. Simulation and real vehicle tests have shown that the designed optimal control strategy significantly improves the energy efficiency and comfort of pure electric passenger vehicle. The simulation shows that, error between electric bus speed and the reference speed is less than1.48%, acceleration and deceleration locate in [-0.9m/s2,1.122m/s2] range, and meets the comfort requirements.(4) Electric bus controller is developed, and achieves a large-scale application. Vector algorithm which has corrected the motor rotor resistance and magnetizing inductance function is applied to motor. The AVL bench test and real vehicle test show that, NMPCESCOP can make the SOC variation of the electric bus reduced by12.5%, acceleration is less than1.122m/s2, deceleration is less than0.9m/s2, the result shows the algorithm significantly improves the energy efficiency and comfort of the electric bus.The work mentioned above has been used in in the1700new energy vehicles of Anhui Ankai automobile limited company, and achieves a large scale of application. These studies not only has important implications for comfort and energy efficiency study on pure electric vehicles, but also has important implications for simplification of optimization algorithm to make it can be used in actual vehicles.