谐振型无电解电容LED驱动器的分析设计

发布时间：2018-05-03 14:48

本文选题：LED驱动器 + 功率因数校正　；参考：《燕山大学》2015年硕士论文

【摘要】：发光二极管(Light Emitting Diode),简称LED,与传统的光源相比具有很大的优势:不仅寿命长,还可以大幅度降低照明用电量,被称为当今2l世纪的绿色环保照明光源。LED驱动器的实质是把输入交流电压转换为稳定的直流电压,产生恒定电流来驱动LED工作。为了提高LED驱动器的寿命和可靠性,必须去除其中的储能电解电容。本文的研究内容即为一种两级式谐振型无电解电容LED驱动电源。两级式LED驱动器由前级功率因数校正(Power Factor Correction,PFC)变换器和后级DC-DC变换器级联而成:PFC变换器可以将输入交流电压变换为直流电压,而后级变换器主要是把该直流电压变换为一个恒定的电流,来驱动LED。本文采用Boost PFC变换器作为前级,分析PFC变换器的输入功率脉动与输入功率因数之间的关系,计算电解电容容量与输出电压脉动的关系。比较了各种去除电解电容的方案,最终确定采用注入谐波的方式,在保证功率因数不小于0.9的前提下,减小电解电容容值并用薄膜电容进行替代。文中,前级Boost PFC变换器工作在电感电流临界连续模式,实现高的功率因数的同时,而且还可以实现开关管的零电流开关,避免了升压二极管的反向恢复问题。后级采用半桥LLC谐振变换器,该变换器不仅可以实现开关管和整流二极管的软开关,还具有较高效率。本文详细分析该驱动电源的工作原理,讨论该方案相应的控制策略,并给出主电路及控制电路参数设计。最后制作完成一台140W谐振型无电解电容LED驱动器的原理样机,并进行了仿真实验验证。实验结果表明本文所提出的方案是可行的。
[Abstract]:Light Emitting Diode, or LED, has a great advantage over conventional light sources: it not only has a long life span, but also greatly reduces the power consumption of lighting. The essence of the green lighting source. Led driver is to convert the input AC voltage into a stable DC voltage and generate a constant current to drive the LED operation. In order to improve the life and reliability of LED driver, the electrolytic capacitance of energy storage must be removed. The research content of this paper is a two-stage resonant LED drive power supply without electrolytic capacitance. The two-stage LED driver is cascaded by the former power factor correction (PFC) converter and the latter DC-DC converter to form a LED converter, which can convert the input AC voltage to DC voltage. The latter converter mainly converts the DC voltage to a constant current to drive the LED. In this paper, the Boost PFC converter is used as the front stage to analyze the relationship between the input power pulsation and the input power factor of the PFC converter, and the relationship between the electrolytic capacitance capacity and the output voltage pulsation is calculated. The methods of removing electrolytic capacitance were compared and the method of injecting harmonics was determined. Under the premise of ensuring power factor not less than 0.9, the capacitance of electrolytic capacitor was reduced and replaced by thin film capacitance. In this paper, the former Boost PFC converter works in the critical continuous mode of inductance current, which can achieve high power factor, and can also realize the zero current switch of the switch tube, thus avoiding the reverse recovery problem of the booster diode. The half-bridge LLC resonant converter is adopted in the rear stage. The converter can not only realize the soft switching of switch and rectifier diode, but also have high efficiency. In this paper, the working principle of the drive power supply is analyzed in detail, the corresponding control strategy of the scheme is discussed, and the design of the main circuit and the control circuit parameters are given. Finally, a 140W resonant LED driver without electrolytic capacitance is fabricated and verified by simulation. The experimental results show that the proposed scheme is feasible.
【学位授予单位】：燕山大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TM46;TM923.34

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