Research And Design Of Electroless Capacitor LED Drive Power

In recent years,people have been committed to the development and design of new lighting source.With its high efficiency,energy saving and environmental protection,long life,high reliability and many other advantages,LED(Light Emitting Diode)is recognized as the most valuable "green" light source in 21st century.Aiming at the problem of mismatch between the drive power supply and the service life of LED light source,this paper mainly studies LED driver power supply without electrolytic capacitor.Based on the analysis of a variety of strategies to eliminate the electrolytic capacitor,this paper will optimize the circuit topology as the main direction,analyze and study the solution to no electrolytic capacitor LED drive circuit topology.This paper is devoted to design a new pulse current LED drive circuit that does not require any electrolytic capacitor or a complex control circuit to reduce the low-frequency output ripple.The circuit is simple,the single-switch topology simplifies the design of the controller,which can be reduced to micro-law storage capacitor,so the film capacitor can be used to replace the unreliable electrolytic capacitors.LED drive power supply is a power converter which transforms AC voltage to stable DC voltage and then supplies it to the LED light source.Since the input power of LED drive power supply is fluctuating,in order to ensure that the output power is constant,the storage capacitor with large-capacity energy is required to balance the instantaneous input power and output power and in general,electrolytic capacitors with large capacity are used as the energy storage capacitors.However,the life of electrolytic capacitors is only a few thousand hours,which is much shorter than the LED life(>50,000 hours),that makes LED drive power supply mismatch with long service life of LED.In order to prolong the service life of power,the electrolytic capacitors in the power supply must be reduced or even eliminated or replaced by other types of capacitors.This paper studies the concept of cascaded DCM flyback converters and designs a new type of no electrolytic capacitor circuit.The working principle,switching mode,parameter design and control circuit design of the circuit topology are discussed in detail,and verified by MATLAB simulation.High efficiency,low cost,high power factor and long-life drive power is the key to ensure the quality of light and the overall performance.This paper analyzed the relationship between the input power factor,the input power ripple and the required storage capacitor capacity.On this basis,a third harmonic injection method is proposed,which injected a third harmonic into the input current of the converter,to ensure that under the condition that the output voltage ripple is constant and the input power factor is not less than 0.9,The storage capacitance is reduced to 65.6%in the improved circuit,and the volume is reduced by nearly 20%,which is verified in a 60W Boost PFC converter prototype,and finally the experimental results are given.By comparing the results of simulation and experiment,the correctness and feasibility of the theoretical analysis are verified,which shows that the circuit has strong practicability and superiority.Through experimental data analysis,the design scheme of the no electrolytic capacitor has the characteristics of high power factor,high efficiency and high reliability,at the same time can meet the requirements of energy saving and environmental protection and EMC testing standards.