Research On The Single-stage LED Driver Based On LLC Resonant Converter

Whether it causes pollution,whether it can simulate natural light,and the energy conversion efficiency is an important standard for contemporary society to test light sources.As a new generation of lighting source,LED not only meets the needs of contemporary society,but also has the advantages of small size,long life and fast response.Therefore,LED is widely used in indoor and outdoor lighting in many fields.As the key section of LED lighting,LED driver is also constantly developing.Compared with the traditional two-stage LED driver,the single-stage LED driver has the advantages of less power conversion times,simpler control,and higher efficiency.Therefore,based on the previous literature,this paper proposes a new single-stage LED driver.The specific research content of the article includes:The single-stage LED driver based on bidirectional magnetizing flyback(BMF)and LLC resonant circuit is analyzed in detail in this paper.The BMF circuit is obtained by sharing the magnetizing inductance of the interleaved flyback circuit.Due to the leakage inductance of the BMF transformer,the BMF circuit is equivalent to the combination of the discontinuous conduction(DCM)boost circuit and the critical conduction(BCM)buck-boost circuit,so the BMF circuit has the better effect of power factor correction(PFC).The BMF transformer turns ratio is set to 1 so that the bus voltage is only slightly higher than the peak of input voltage,coupled with the soft switching characteristics of the LLC resonant circuit,the system has better efficiency.Aiming at the voltage instability problem of single-stage LED drive buffer capacitor,the output power of BMF circuit and the input power of LLC resonant circuit of the proposed LED driver are analyzed in detail with the switching frequency.The design steps of system parameters are given in detail,including BMF transformer,resonant transformer,selection of main semiconductor components and main hardware circuit.The extended description function(EDF)method is used to analyze and model the LLC resonant circuit,and then the system is compensated according to the system compensation theory.The system has been verified through simulation and experiment.The designed prototype has a power factor of 0.991,a THD of 9.7%,and an efficiency of 90.8% under rated conditions.Finally,according to simulation and experiment,compare the proposed LED driver in this paper with the topology mentioned in the previous literature,and draw the comparison results into a table.