Modelling And Analysis Of Drive System Of Intelligent LED Headlamp

At present,intelligent LED headlamp,on account of its advantages of high-efficiency,energy conservation and safety,plays a significantly important role in the field of automotive lighting,which has improved the safety of night driving greatly.As the power module for LED,drive system of intelligent LED headlamp is faced with technical problems such as stability that depends heavily on hardware conditions and insufficient intelligence,which restrict the transformation,upgrading and promotion of automotive LED headlights in the direction of small size,high performance and self-adaptation.In this paper,by modelling,analyzing and designing the anti-glare lighting control strategy of the high beam LED part of the drive system of intelligent LED headlight,it improves the stability and intelligence of the drive system of intelligent LED headlight without increasing the hardware cost:First,in accordance with the operating principle of constant-current LED drive system,a first-order matrix differential equation is used to preliminarily establish its switched linear system model,and the model is approximately discretized.Taking into account that the working mode of the intelligent LED drive system will be affected by various factors such as ambient light,temperature changes,road changes and system constant current mechanism during the driving of the car,the transition probability model of the polyhedral structure is used to describe the switching rules of system mode.The state space expression of the corresponding discrete-time inhomogeneous Markovian jump linear system model is constructed,that is,the constant current LED drive model.Secondly,the direct analysis method based on Lyapunov function is used to make a defined stability analysis of the obtained discrete-time inhomogeneous Markovian jump linear system model.Through the proof,in the form of linear matrix inequality,the criteria for the constant current LED drive model is established to satisfy asymptotic stability,finite time boundedness and finite-horizon l₂l-l_∞performance at the same time.Within the solution range of the theoretical criteria,we calculate the optimization problem for the objective function,and design the intelligent LED drive system parameters under the optimal quantitative performance index.Based on the optimal system parameters designed,the dynamic characteristics of the constant current LED drive model are numerically simulated in MATLAB,and then the software Multisim is used to simulate the constant current LED drive system under this parameter to verify the correctness and validity of the theoretical results.On the basis of the theoretical criteria and optimization algorithm of the proposed constant current LED drive model,the LED drive system of low beam and high beam is designed by using LED constant current driving chips GM9910B and MT7202,respectively.The work content includes driving principle design,circuit diagram drawing and physical proofing test.In the design of the driving principle,it is mainly to use the proposed theoretical criteria to design the parameters of the energy storage element of the output loop,designing the sampling resistance to adjust the LED power,and add various system protection circuits.The corresponding circuit diagram is drawn with comprehensive consideration of current,heat dissipation,and chip stability.After completing the design,we conduct electrical efficiency test and luminous flux test on the proofed circuit board to check the quality of the product.In addition,in view of the intelligent control requirements of the high beam part,the STC15W202S microcontroller is used to complete the design of the LED main control system,and the actual product is proofed.The working principle of the LED main control system mainly includes two parts:power input protection and voltage conversion.Based on the designed hardware,an anti-glare lighting control strategy for the optical partition is designed.The principle of this control strategy can adapt to the needs of the environmental luminosity and the change of the road conditions,the gradual control of the LED high beam,and the formation of moving dark areas for other vehicles.Finally,the designed anti-glare lighting effect is demonstrated through an application example of the algorithm.