Research And Design Of LED Street Lamp Special Digital Power Supply

Energy conservation is an important goal of the development of global economy.Lighting make up 20% of the world's energy consumption.LED lighting is known as the fourth generation lighting because of its excellent characteristics such as energy saving,environmental protection and long service life.As a diode,LED is drived by direct current,and constant-current drive is preferred.Its performance is greatly affected by the drive power supply.Therefore,the study of reliable driving power supply has a great significance to the development of LED lighting.This thesis according to the market demand for LED street lamp driving power supply,puts forward the design requirements of digital power supply with AC 220 V input and 48 V 3.2A output.It can choose constant current mode or constant voltage mode for demand.It can communicate with other CPUs to change the output voltage or current.This thesis designs the digital power supply in hardware and software.In the hardware part,the design process of power factor correction circuit and half-bridge LLC resonant converter is introduced in detail.Power factor correction is based on UCC28019 chip design,using the typical application Boost topology.The half-bridge LLC resonant converter is designed by FHA fundamental wave analysis method which is widely used at present,and the high-frequency transformer is designed by AP method.The auxiliary circuits such as input protection circuit and MOSFET driving circuit are introduced briefly as well.In the software part,the digital compensator is designed by incremental PI control algorithm.The flowchart of the main program such as master routine and softstart routine are given.According to the design scheme,Simplis is used to simulate the power factor correction and uncompensated half-bridge LLC resonant converter.The simulation results show that the design parameters are reasonable.The experimental prototype of digital power supply is made and the PWM generation module,communication module and power level output module are tested.The experimental results show that the design scheme is reasonable and feasible.