LED路灯恒流驱动开关电源设计
摘 要：LED作为新型光源取代传统照明设备已成为趋势，LED具有高效、节能环保、寿命长等优点，但是目前的LED路灯恒流驱动电源存在输出功率低、转换效率差、功率因数不高、输出特性不稳定等问题，严重影响了LED路灯的推广使用。本文在对反激式开关电源的拓扑结构及其工作原理分析的基础之上设计了反激式开关电源的主体电路，功率因数校正电路和反馈电路，根据电磁学理论对变压器进行优化设计，从而提高了驱动电源的性能，最后设计出一种通用的恒流源驱动开关电源，该电源选择采用高频隔离变压器和运算放大器构成的反馈系统，既保证较高的功率因数,改善电网影响,又保证高效率,控制简单,可靠实用,具有一定的应用价值。57476
毕业论文关键词：恒流驱动电源， LED，反激式变换器，功率因数校正
Abstract: As a new substitute for traditional lighting fixture, LED is characterized with high efficiency, energy saving and durability. However, the crosscurrent driving power of LED street light faces problems of low output power, poor conversion efficiency, lower power factor and instability in output, seriously affecting the spread use of LED street light. Based on analysis of topology of flyback switching power supply and its working principle, the main circuit flyback switching power supply, power factor correction circuit and feedback circuit are designed in this thesis. According to electromagnetic theory, the design of transformer is optimized, thereby improving the performance of the driving power. At last, a switching power supply driven by universal constant current source is designed. This power supply adopts high-frequency isolation transformer and feedback system consisting of an operational amplifier, ensuring high power factor, improving grid impact, and guarantying high efficiency, reliability and practicality, giving it a certain application value.
Keywords：constant current drive power，LED，flyback converter，power factor correction
1 绪论 5
1.1课题背景 5
1.3存在的问题 5
1.4本课题的主要工作 6
2 开关电源基本原理与LED伏安特性 6
2.1 DC/DC变换器拓扑结构 6
2.1.1降压式变换器 6
2.1.2升压式变换器 7
2.1.3升降压式变换器 7
2.1.4正激式变换器 8
2.1.5反激式变换器 8
2.2 LED的伏安特性 11
3开关电源各模块设计 11
3.1电源控制芯片 12
3.1.1电源控制芯片选择 12
3.2 EMI滤波器设计 13
3.3功率因数校正技术 13
3.3.1无源功率因数校正技术 14
3.3.2 有源功率因数校正技术 14
3.4反馈电路的设计 14
3.4.1恒流反馈控制电路设计 14
3.4.2限压保护电路设计 15
4变压器的优化设计 15
4.1变压器绕组极性 16
4.1.2反激式变换器中变压器功能及其占空比