Design And Performance Analysis Of An Electronic Variable Valve Based On BLDC Motor

Electronic variable valve technology can adjust valve timing and lift in real time according to actual working conditions.It is one of the effective methods to improve the performance of automobile engine.Based on the research analysis of existing variable valve technology,an electronic variable valve system based on a BLDC motor was proposed in the paper.The system had a relatively simple structure,high response speed and good seat performance,which could achieve fully flexible regulation of the valve.The structural design,control methods and performance analysis were studied by theoretical analysis,system simulation and test methods.Specific research work is as follows:(1)The overall design scheme of electronic variable valve based on BLDC motor was presented.The performance requirements of the system design were analyzed,and the different forms of actuators and transmission mechanisms were evaluated for this scheme,and the overall scheme of electronic variable valves based on BLDC was obtained.(2)The overall structure design of the electronic variable valve was completed.Through the theoretical analysis of the system,the maximum acceleration of valve movement was taken as the main design target,the BLDC motor was parameterized by electromagnetic field finite element simulation software,and the transmission mechanism as the main components of the system was designed,the feasibility of the design structure was verified by theoretical verification.(3)The mathematical modeling of mechanical,magnetic and circuit subsystems of electronic variable valves were carried out.On this basis,three closed-loop control schemes of position loop,speed loop and current loop were designed,and a position loop control strategy based on CMAC-PID compound control was proposed.The system was simulated and analyzed based on Matlab/Simulink,the system performance was analyzed,and the feasibility of the algorithm was verified,which laid a foundation for subsequent tests.(4)The test bench construction and system test research were completed.The control system scheme was designed based on d SPACE controller,and on this basis,relevant software and hardware design was completed,and the system test bench was built.The experimental results showed that the valve transition time,seating speed and maximum lift meet the design requirements which could realize the fully variable performance of the valve well.