具有PWM调光功能的无电解电容LED照明驱动研究

发布时间：2018-01-10 09:40

本文关键词：具有PWM调光功能的无电解电容LED照明驱动研究　出处：《西南交通大学》2017年硕士论文　论文类型：学位论文

【摘要】：电解电容是影响LED照明驱动寿命的主要元件,因此,电解电容消除技术成为LED照明驱动研究的热点。传统的AC/DC LED照明驱动一般采用AC/DC变换器级联LED电流调节器的两级架构,虽然能够消除电解电容,实现恒流输出,但存在电路复杂、成本高、效率低等问题。同时,为了实现进一步能量节省和适应不同的应用需求,PWM调光功能已成为LED照明驱动必备功能之一。为此,论文以基于低频纹波对消技术的准单级LED照明驱动架构为研究对象,研究具有PWM调光功能的无电解电容LED照明驱动。目前低频纹波对消技术仅研究了单串LED负载的情况,无法直接应用于多串LED负载,且未实现PWM调光功能。论文以此为切入点,系统讨论了前级FlybackAC/DC变换器和后级非隔离DC-DC变换器(重点考虑Buck变换器拓扑)的拓扑连接方式以及PWM调光下系统参数的设计。基于低频纹波对消技术的LED照明驱动中前级AC/DC变换器通常采用CRM FlybackAC/DC变换器,存在在全负载范围和线周期内开关管开关频率变化范围较宽,开关损耗大,变换器效率低的问题。将准谐振技术引入具有功率因数校正功能的FlybackAC/DC变换器,通过加入开关管最小关断时间Toff_min控制,在实现主开关管谷值开通的同时,减小了开关频率的变化范围,降低了开关损耗,提高了变换器的效率。详细分析了准谐振Flyback AC/DC变换器的工作原理、功率因数PF和控制策略。以两串LED负载为例,详细阐述了低频纹波对消架构中Bus电压的选取原则,分别给出了前级Flyback AC/DC变换器和后级Floating Buck变换器电路参数设计。实验室研制了两台40W的原理样机,实验结果验证了方案的可行性和设计的合理性。
[Abstract]:Electrolytic capacitor is the main component, LED lighting driving life so eliminating electrolytic capacitor technology has become a hotspot to drive LED lighting. The traditional AC/DC LED lighting driver two using AC/DC converter cascaded LED current regulator architecture, although can eliminate the electrolytic capacitor, constant current output, but the existence of complex circuit high cost and low efficiency. At the same time, in order to achieve further energy saving and adapt to the needs of different applications, PWM dimming function has become one of the essential functions of LED lighting. This paper based on low frequency ripple cancellation technology of quasi single stage LED lighting driver architecture as the research object, no electrolytic capacitor LED lighting driver is studied PWM dimming function. The low-frequency ripple cancellation of only a single strand of LED load, can not be directly applied to the series LED load, and did not realize the PWM dimming function based on. This is the starting point of the system, discussed the first level FlybackAC/DC converter and a non isolated DC-DC converter (Buck converter topology is focus on the design of system parameters) topology connection and PWM dimming. The low frequency ripple cancellation technology of LED lighting in the first stage AC/DC converter usually adopts CRM FlybackAC/DC transform based on the existing in the full load range and line cycle switching frequency range is relatively wide, large switching loss, low efficiency of the converter. The quasi resonant technology into FlybackAC/DC converter with power factor correction function, by adding minimum switch off time Toff_min control, opened at the same time in the realization of value the main switch Valley, reduces change range of switching frequency, reducing the switching losses and improve the efficiency of the converter. A detailed analysis of the working principle of Flyback quasi resonant AC/DC converter, power Factor PF and control strategy. In the two series LED load as an example, elaborated on the selection principle of eliminating low frequency ripple voltage of Bus in the architecture are given, the former Flyback AC/DC converter and Floating stage Buck converter circuit parameter design. The principle prototype of two 40W was developed. The experimental results verify the rationality the feasibility and design scheme.

【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM46;TM923.34

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