A Design Of LED Power Supply Based On Half-bridge LLC Converter

With the increasing demand for display devices,various new display technologies are beding studied in the market,such as the latest OLED display technology.Better display technology requires its power supply equipment to become more precise and stable.Switching power supply,in particular,LED switching power supply,are widely used in various applications,including outdoor display,LED television display equipment and other machinery and equipment.Nowadays,the market for high-quality switching power supply has become more and more large.Compared with foreign enterprises and institutions,they have more advanced technology and equipment,high-quality switching power supply in the field of leadership position.But in recent years,the domestic various types of power R & D and production enterprises after long-term technology accumulation,it has achieve a great development in this field,and successively launched a number of industrial and civilian power products,which can compensate for the gap between the advanced enterprises and foreign countries.With the concept of green power supply,using the excellent AC/DC converter technology widely will inevitably improve the current social energy shortage,which makes it important to study the scheme.According to the actual demand of switching power supply equipment in the current market,this paper designs a switching power supply with an input voltage of AC 90~264V and an output power of 300 W.Firstly,this paper introduces the background,present situation and development trend of this thesis,and explains the practical reference value of the design for economic and social development.Then,the working principle of PFC is introduced in detail;the PFC circuits of different topological structures are analyzed;the advantages and disadvantages of these are compared;the PFC technology adopted which is APFC on Boost in this design is determined with an input voltage of 90~264V and an output voltage of DC 400V;and the peripheral circuits and control circuits are given in detail design process.Secondly,the working principle of the resonant converter is analyzed in detail.In many types of resonant converters,it is important to choose a scheme that can effectively improve the switching frequency and reduce the loss of the device.How to design the appropriate circuit parameters is very important for the optimization of the system.This design will analyze the influence of resonant parameters on the performance of the work,and analyze the equivalent circuit of DC/DC converter in detail,study its gain characteristics and impedance characteristics,finally determine the control strategy of this design,give the specific design process with an input voltage of DC 400 V and three output voltages of 5V,12 V and 24 V,and deal with the problems.Thirdly,the constant current circuit and auxiliary power supply are designed.Finally,the prototype is made and tested,and the test results are analyzed briefly.In the conclusion and prospect section,we summarize the goals and problems of the design,and look forward to the future work.