Research On Control System Of Air Conditioning Compressor For Electric Vehicle

With the increasingly prominent problems of energy and environmental crisis,people’s family cars are more inclined to energy-saving and environment-friendly electric vehicles.The automotive air conditioning system is an indispensable part of the electric vehicle system,which affects the driving comfort and the size of vehicle energy consumption.In the air-conditioning system,the air-conditioning compressor is the main power source of the whole air-conditioning system.Due to the cancellation of the fuel vehicle engine in the electric vehicle,the driving mode of the air-conditioning compressor has changed from the original belt drive of the traditional car to the electric drive.The quality of the air-conditioning compressor control system affects the excellent performance of the whole air-conditioning system,and at the same time,in order to improve the safety and reliability of the air-conditioning system,At present,the air-conditioning compressor motor is a sensorless permanent magnet synchronous motor,which is more complex than the traditional air-conditioning compressor control system.Therefore,it is of great significance to study the control system of air conditioning compressor.This paper investigates the current research status of air-conditioning compressor control strategies for electric vehicles,analyzes and compares the advantages and disadvantages of different control strategies and existing improvement schemes,and elaborates that the research on permanent magnet synchronous motor system control for new energy vehicles is of great significance.The existing problems of the control system have formulated the research goals and main tasks of this article.This paper designs the overall scheme of the system.In terms of the system hardware scheme,the main control unit,drive module,and power frame are designed separately;in terms of the software scheme,the system architecture is designed and introduced in layers.Through the analysis and comparison of the existing control modes,it is determined that this article adopts the vector control mode scheme.Analyzed the motor control strategy of the electric vehicle air-conditioning compressor,and finally determined the compound control scheme of I/F open-loop control and sliding mode observer control in this paper.In the study of air-conditioning compressor motor control strategy,the motor vector control framework was built;the traditional sliding mode observer algorithm for medium and high speed was improved,and the adaptive sliding mode observer based on PLL was designed to weaken the system chattering.Improve the position observation accuracy,enhance the real-time followability of position estimation,and enhance the robustness of the system.It provides a good solution;for the I/F control strategy at zero and low speed,two-stage pre-positioning and smooth angle switching control are adopted.The scheme provides a good solution to the problem of motor pre-positioning dead center and angle switching torque impact.The simulation model of this control strategy was established on the MATLAB/SIMULINK platform,the stability of the vector control based on SVPWM was tested,the reliability of the rotor position estimation based on the PLL-based adaptive sliding mode observer was analyzed,and the I/F startup was verified.Feasibility of smooth switching of control and angle.Finally,this paper used NXPS32K144 as the system control core to design a set of electric vehicle air-conditioning compressor control system,and introduced the hardware design and software design of the system in detail.According to the designed control system,the hardware,software and whole machine debugging of the system were carried out.The control strategy of the control system was verified by experiments,and its control performance was tested.The experimental results show that the control system meets the expected results and is practical.