Research On Single-stage AC/DC LED Driver Based On Flyback Circuit

In the context of the contemporary development of clean energy and the promotion of energy green transformation,improving the energy utilization efficiency of the lighting link can make a great contribution to green development.As an important industry of green lighting,LED lighting has gradually become the mainstream product in the lighting market.As the core part of LED,LED driver realizes the high efficiency,high power factor and topology simplification of the driver,which has become a hot spot in various circles in recent years.Under the premise of meeting the requirements of international harmonic standard IEC 61000-3-2,in order to improve the conversion efficiency of the driver and reduce the energy loss,this paper proposes a single-stage AC/DC LED driver based on bridgeless flyback circuit with high efficiency and high power factor.This article addresses the problem of large loss of four bridge diodes in traditional flyback LED drivers.By using bidirectional power switches instead of diode rectifier bridges,and adding a winding at the output side,the topology is improved to achieve the overall high efficiency of the driver.The main topology of the driver adopts a flyback single-stage PFC circuit,the circuit works in discontinuous conduction mode,and it is used to realize the functions of power factor correction and regulated output.Through the analysis of the main circuit and the control circuit,the design of the key component parameters in the driver and the selection of the model are carried out.The control circuit adopts the fixed frequency pulse width modulation chip TL494,and the drive of the bidirectional power switch adopts the photocoupler isolation chip HCPL-3120.Then the PSIM simulation software SIMCAD is used to complete the construction of the circuit model and the simulation is carried out in the closed loop state.Through detailed comparison and analysis of the simulation waveforms of the traditional flyback LED driver and the proposed LED driver,the correctness of the theoretical analysis results is verified.According to the design of hardware circuit,the printed circuit board is made,and the experimental prototype is built.The experimental results show that compared to the traditional flyback LED driver,the LED driver proposed in this paper has a higher power conversion efficiency of 3.2%,a power factor greater than 0.95,and a stable output voltage of 48 V.By comparing the experimental test results with the theoretical data,the validity of the designed driver is verified.