Design Of High Power LED Driver Power Supply With Adaptive Dimming Function

As a green environmental light source in the 21 st century,LED has developed into a sunrise industry in the 21 st century with its advantages of high brightness,low power consumption,fast response and small size.However,the LED lamp can not use the public grid voltage directly like the common incandescent lamp.It must be provided with a stable voltage and current by a special driving power supply.But at present,the problems of low power factor and low power conversion efficiency are common in LED driving power supply.These problems seriously restrict the development of LED industry.In addition,in order to meet the comfort and environmental protection requirements of modern lighting,if the adaptive dimming of LED can be realized,not only can the waste of electric energy be reduced,but also the service life of LED can be prolonged.Therefore,this paper designs an LED driver with power factor correction function and adaptive dimming.This paper mainly completes the following tasks:(1)Firstly,the related technologies of LED,LED driver power supply and power factor correction are analyzed and studied.(2)The whole circuit of LED driving power supply is designed.The whole circuit includes main circuit and control circuit.The main circuit includes input protection circuit,EMI filter circuit,rectifier circuit,active power factor correction circuit,RCD buffer absorption circuit and flyback conversion circuit.The control circuit includes the minimum system of DSP,current detection circuit,temperature detection circuit,infrared detection circuit of human body and environmental light detection circuit.(3)The control algorithm of driving power supply is studied.The improved single neuron adaptive PID algorithm is used to control the driving power supply.The adaptive dimming function is realized,and the software design is completed.Among them,the software program design includes: control system main program,current sampling subroutine,temperature detection and overtemperature protection subroutine,human infrared detection subroutine,environmental light detection subroutine,improved single neuron adaptive PID control subroutine,PWM wave generation subroutine and interruption subroutine.(4)The simulation and experiment of the LED driving power supply are carried out.The simulation analysis of the active power factor correction circuit proves that the total harmonic distortion can be greatly reduced by the active power factor correction,which can avoid serious pollution to the power grid,and the feasibility of the control algorithm of the driving power supply is verified.Secondly,the experiment platform of adaptive dimming driver power supply is built to carry out the experiment of adaptive dimming of driving power supply.The experimental results show that the hardware circuit and software designed in this paper are correct.The self-adaptive dimming driving power supply designed can adjust the brightness of LED lamps according to the different ambient illumination,and maintain the stability of ambient illumination.