LED调光驱动电源的研究与设计

发布时间：2018-04-21 06:03

本文选题：LED驱动电源 + 可调光　；参考：《陕西科技大学》2014年硕士论文

【摘要】：新一代的绿色节能LED照明，凭借着其节能环保、长寿命、数字调控方便等优势已经成为全球化的趋势。作为LED照明光源不可或缺的关键组件——LED驱动电源，它在灯具中的作用就好比像人的心脏一样无比关键与重要，电源品质制约着LED产品的可靠性与其商业化应用。本文对功率因数校正技术、调光控制方式、反激式变换器、电磁兼容问题等关键模块进行分析研究，设计了一款输出为40V/350mA可调光的隔离式LED驱动电源。其主要工作与结果如下：（1）功率因数校正技术的研究。本文选择两级结构，前级AC/DC采用升压变换器实现功率因数校正，后级DC/DC级采用反激变换器工作于临界模式实现恒流驱动，功率因数达到0.93以上。（2）调光中闪烁问题的解决。针对调光过程中存在的闪烁问题，设计无源泄放电路电路。LED出现闪烁的主要原因有：在TRIAC导通的瞬间会产生一个大的尖峰电流，引起电路振荡，在电路中加入阻尼电路，抑制该尖峰电流；在调光器导通过程中，需要有一个维持电流IH维持其导通，否则电流低于IH时，调光器关断，如此反复，使调光器误触发引起LED闪烁。因此，设计无源泄放电路，避免调光器误触发，实现平稳调光，范围在1%~100%。（3）控制电路的研究。对电路的控制方式以及驱动电源控制策略进行研究分析，选择原边恒流控制的方式，并利用数字控制芯片，实现电路的恒流输出。采用原边恒流控制的方案，去除了副边光耦控制，减少反馈回路，使电路结构更加简化。结果表明电流实现恒流输出，，且电流的变化范围小于5%。（4）EMI滤波电路的设计。针对LED驱动电路中的电磁兼容问题，分析了电磁兼容产生的原因，根据电磁干扰的三要素提出电磁干扰的抑制措施。设计EMI滤波电路，有效地抑制传导干扰。本文实现了低成本可调光的LED调光电源。本电源的性能指标如下：该电源的调光范围可达1%~100%，实现无闪烁平稳调光；且在无调光模式下，功率因数可达0.93以上，效率在0.80以上，恒流范围小于5%，具有较好的实用性能与应用前景。
[Abstract]:The new generation of green energy-saving LED lighting has become a global trend with its advantages of energy saving and environmental protection, long life, convenient digital control and so on. As an indispensable key component of LED lighting source, LED-driven power supply plays an important role in lamps and lanterns just like the human heart. The quality of power supply restricts the reliability and commercial application of LED products. In this paper, the key modules such as power factor correction technology, dimming control mode, flyback converter and EMC are analyzed and studied. An isolated LED driver with output of 40V/350mA dimming light is designed. Its main work and results are as follows: Research on Power Factor Correction (PFC). In this paper, the two-stage structure is chosen. The former stage AC/DC adopts boost converter to realize power factor correction, the latter stage uses flyback converter to work in critical mode to realize constant current drive, and the power factor is above 0.93. (2) the solution of the flicker problem in dimming. Aiming at the flicker problem in the dimming process, the main reasons for the design of the passive discharge circuit circuit. The main reasons are as follows: a large peak current will be produced at the moment of TRIAC conduction, which will cause the circuit to oscillate, and a damping circuit will be added to the circuit. In the process of the dimmer conduction, it is necessary to have a maintenance current IH to maintain its conduction. Otherwise, when the current is lower than IH, the dimmer is turned off and repeated so that the dimmer may mistrigger and cause LED scintillation. Therefore, the passive discharge circuit is designed to avoid the misfiring of dimmer and to realize smooth dimming, which ranges from 1 to 100. Research on control circuit. The control mode of the circuit and the control strategy of the driving power supply are studied and analyzed. The original side constant current control mode is selected and the constant current output of the circuit is realized by using the digital control chip. The primary edge constant current control scheme is adopted to eliminate the secondary edge optical coupling control and reduce the feedback loop, which makes the circuit structure more simplified. The results show that the current output is constant current, and the current range is less than 5. Design of EMI filter circuit. Aiming at the problem of EMC in LED driving circuit, the causes of EMC are analyzed, and the measures to restrain EMI are put forward according to the three elements of EMI. EMI filter circuit is designed to suppress conduction interference effectively. In this paper, a low cost tunable LED dimming power supply is realized. The performance indexes of the power supply are as follows: the dimming range of the power supply can reach 1 / 100, and the power factor can reach above 0.93 and the efficiency is more than 0.80 in the non-flashing and stable dimming mode. The constant-current range is less than 5, so it has good practical performance and application prospect.
【学位授予单位】：陕西科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM923.34;TM46

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