LED无级调光电源系统设计（代做电子毕业设计）
摘要
伴随着科技和应用技术的进步，与LED有关的驱动以及调光技术的发展，将不断的创新与完善，其对节能减排，降低能耗的大环境下具有着更高的价值，并将对照明产业起到重要的革命性作用。
一般情况下，每一种电源都必须在具有前端驱动电路的前提下，才能够给LED供电。白炽灯是通过普通电压源来进行运作，利用其端电压电流关系特性为线性关系的缘故。与纯阻性的普通白炽灯运行原理不同，LED为指数形式的伏安特性曲线，简单的讲，通过LED的电压和电流呈非线性关系，且电源电压即便有微小的调整，经过LED负载的电流也能够产生非常大的变化。如果LED供电选用电压源，会造成电压微微变大，电流却增长过大，导致温升变大，因而，可能损坏LED灯。所以除去上述方法，通过选用恒流源来达到最大程度的控制温升的目的。对LED灯设计专门的电源驱动电路，来完成对电流的恒定控制。保护LED灯的最佳方法，应先从保持电流的恒定性来入手，所以一般LED驱动设计选用恒流源居多。
本篇的设计方案结构为，首先了解LED发光的原理以及特性，然后基于PWM的技术，设计了能够控制LED的亮度的电源电路，其主要目的在于能够为LED输出恒定的驱动电流，进而能够令LED负载稳定且安全的运行，以及利用PWM技术来精确控制流经LED灯组的电流。。论文通过对几种LED恒流驱动转换方案的原理以及优缺点进行了阐述和分析，简单描述了各方案对应不同场合的选择;大体说明了三种调光方法的原理，也包括优缺点，相互对比之后，考虑到LED恒流驱动的实际应用，选出基于PWM调光技术作为前提的控制方案;最后，论文对本课题所设计的各个部分进行主要说明，包括恒流驱动电路、功率因数校正电路以及调光系统电路、通讯电路的结构与工作原理，之中又对PCB板的焊接及整个灯组进行了制作与装配。测试了在占空比不同下的PWM信号所生成的亮度，验证了LED灯组运行的可靠性及效果，完成了本次设计的LED无级调光电源系统。
关键词:LED驱动电源电路，PWM，恒流驱动，功率因数校正
Abstract
With the advances in technology and application of technology, as well
as driving the development of LED-related dimming technology, the constant innovation and improvement of its energy conservation, reducing energy consumption under the environment has a higher value, and lighting
industry has played an important revolutionary role.
Under normal circumstances, each of the power supply must be in the context of the drive circuit having a front end, to be able to power the LED. Ordinary incandescent lamp by a voltage source to operate with its current relationship between the terminal voltage characteristic for the
sake of a linear relationship. Pure resistive operating principle different from ordinary incandescent, LED is exponential current characteristic, simply speaking, the voltage and current through the LED is nonlinear, and the power supply voltage even with minor adjustments, through the LED load current can produce very big change. If the LED supply voltage source selection, will cause voltage slightly larger, but the current increase is too large, resulting in temperature rise becomes large,and therefore, may damage the LED lights. Therefore, removing the above-described method, through the selection of a constant current source to achieve the greatest degree of temperature control purposes. LED lamps are designed specifically for the power driver circuit to complete the constant current control. The best way to protect the LED lights should start to keep current constant resistance to start, it is generally a constant current source LED driver design choice majority.
This article design structure, first understand the principle and characteristics of the LED light, and then based on PWM technology that is designed to control LED brightness can be a power supply circuit, its main purpose is to be able to output a constant LED drive current, and thus be able to make LED load stable and safe operation, and the use of PWM technology to precisely control the current flowing through the LED group. Paper by the principles and advantages and disadvantages of LED constant current driver conversion programs were discussed and analyzed, a brief description of the programs corresponding to different occasions choice; generally explains the three dimming principles, including advantages and disadvantages of each other after comparison, taking into account the practical application of LED constant current drive, select PWM-based dimming control scheme as a prerequisite; Finally, the paper of the various parts of this project are designed mainly be described, including the constant current drive circuit, power factor correction circuit and a dimming system circuit, communication circuit structure and working principle, but also among the PCB board welding and the entire group of lamps production and assembly. Tested at different duty cycles of the PWM signal generated by the luminance, verify the effectiveness and reliability of LED lamps run, completing the LED stepless dimming
power supply system of this design.
Keywords: LED driver power supply circuit, PWM, constant current drive, power factor correction
第一章 绪论
1.1 LED无级调光电源系统的背景及意义…………………………………1
1.1.1技术背景……………………………………………………………1
1.2 LED无级调光电源系统的国内外研究现状……………………………2
1.2.1国内现状……………………………………………………………2
1.2.2国外现状……………………………………………………………2
1.2.3 LED电源技术………………………………………………………2
1.3 LED无级调光电源系统的技术特点………………………………………3
1.4 LED无级调光电源系统研究内容…………………………………………5
第二章 LED无级调光电源系统的系统框图……………………………………6
2.1 LED无级调光电源总体设计思想…………………………………………6
2.2 LED无级调光电源的硬件电路框图………………………………………6
2.3 LED无级调光电源的软件流程……………………………………………6
2.4 LED无级调光电源简要工作原理…………………………………………7
第三章LED无级调光电源系统的硬件设计……………………………………7
3.1 LED无级调光电源系统硬件电路设计思想……………………………7
3.2 LED无级调光电源系统分电路设计……………………………………7
3.2.1 EMI滤波…………………………………………………………………7
3.2.2功率因数校正……………………………………………………………8
3.2.3通讯电路模块…………………………………………………………9
3.2.4调光横流电路模块……………………………………………………12
第四章软件设计………………………………………………………………19
4.1 流程图…………………………………………………………………19
4.1.1系统主程序流程图……………………………………………………19
4.2 程序……………………………………………………………………21
第五章硬件系统的调试………………………………………………………21
第六章总结………………………………………………………………29
附录………………………………………………………………………33
参考文献…………………………………………………………………34
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