A High Power Factor Flicker-Free LED Driver Design

Nowadays,the world is increasingly concerned about the energy problems,among which the rational use of electric energy constitutes an important aspect of energy saving,while the lighting power consumption occupies an important proportion in the world's electricity consumption.With the development of semiconductor lighting technology,high-power LED has been widely used as a new lighting source in line with the concept of green lighting because of its energy conservation,high efficiency,environmental protection,high reliability and long life.Starting from the modern lighting system,the LED driving power supply studied in this paper has two main characteristics:high power factor and no stroboscopic.The characteristics of LED light source determine the demand for constant current drive.This thesis compares advantages and disadvantages between several main driving modes,and makes a detailed introduction to the strobe problems existing in current LED lighting drive,summarizes the main technologies of current strobe free lighting,and clarifies the requirements for future LED driver.A two-stage stroboscopic strobos-free scheme based on Boost topology active power factor correction converter and PSR feedback based quasi-resonant Flyback converter is determined.On the basis of comparing the control methods of active power factor correction(APFC),this paper emphatically analyzes how the Boost topology of COT control realizes PFC function and analyzes its shortcomings.Based on COT control,an improved scheme of COT control is proposed,which optimizes the shortcomings of the COT controlled BOOST and greatly improves the power factor and harmonic content of the former BOOST converter.The main power parameters were designed and the simulation model was built to verify the control mode and power level.This thesis analyzes the working principle and constant current control mode of quasi-resonant Flyback circuit in the application of post-stage DC/DC,and analyzes the implementation principle of PSR from the mathematical point of view.The problem of constant current output load adjustment rate is analyzed,and the method of output voltage feedback is put forward to optimize the load adjustment rate.Based on SIMPLIS software,the simulation on the loop is carried out to ensure the stability of the system.Finally,based on the analysis results of the full text,the physical production and testing are carried out.According to the analysis of the experimental results,the measurement data show that after the active power factor correction,the power factor and harmonic content are optimized,the efficiency and the performance of the on-off test are fairly good,and the output stroboscopic problem is also solved,proving the feasibility of the high-power factor stroboscopic LED drive power supply proposed in this thesis.