【作者】 桂巍；

【导师】 庄圣贤；

【作者基本信息】 西南交通大学 ， 电路与系统， 2013， 硕士

【摘要】 绿色照明是人类社会可持续发展需要解决的重要问题之一,LED作为最具发展潜力的新型绿色光源之一,由于其节能、环保、高效、寿命长、应用广泛等特点,时下正引领人类照明工业的第四次飞跃,受到了世界上各个国家的高度关注。由于LED自身的伏安特性需要输出恒流,而开关变换器在驱动LED电路中具有恒流、效率高等优点,因此它被广泛应用于LED驱动电路中。本文以DC-DC Boost电路的LED驱动电路作为研究对象,对单电感多路输出的峰值电流控制技术在其变换器上的应用进行了详细的分析研究。本文首先介绍了高亮白光LED的电气特性和工作特点,确定了LED驱动电路最好采用恒流的方式进行驱动；接着对比了几种恒流驱动技术,采用单电感多路输出技术的开关变换器因只采用一个电感,在分时复用的情况下可实现多路输出,在节约成本上和减小体积上有优势,成为本文研究重点。本文以非隔离Boost电路的单电感双路输出LED驱动电路为例,分析研究了DC-DC恒流驱动方式；由于驱动电路需要恒流反馈调节,本文采用了峰值电流控制方法；为了抑制峰值电流反馈造成的次谐波振荡,在电路中增加了PID控制电路模块,对电路进行补偿。本文采用理论与实验相结合的方式,首先应用状态空间平均法对LED驱动电路进行建模,分析了DCM模式下电路的工作状态及小信号模型,导出稳态方程和传递函数；接着分析了峰值电流控制模式及添加PID控制电路后电路的稳定性,得到驱动电路小信号模型框图和整个系统开环传递函数,进而分析了整个系统的开环稳定性和闭环稳定性。最后对驱动电路进行软件仿真和试验验证,以非隔离型Boost电路的单电感双路输出高亮LED驱动电路为例设计并制作了驱动电路样机,详细介绍了主电路、控制电路及补偿电路的设计方案,并对其电路性能进行了测试。测试结果基本满足测试预期。更多还原

【Abstract】 Green lighting is the one of significant issue for human society’s sustainable development. LED is a new green light, and also is the one of the most potential for development, because of its energy saving, environmental protection, high efficiency, long using time and wide application. It’s leading the forth evolution of human’s lighting industry, also, is paid high attention by most of countries in the world. Due to the volt-ampere characters itself, LED needs constant current in outputs. Meanwhile, using switch converter in LED driver has the ablility of constant current output and high efficiency, so it is used widely in LED drivers. This paper studied in DC-DC Boost circuit in LED drivers, besides, in this paper, technologies with Single-Inductor Multiple outputs and Peak Current Mode are used in this converter.This paper introduced the electrical specifications and features of highlight white LED; and it showed LED had better use constant current driver. Secondly, compared some technologies with constant current, and then chose the technology of Single Inductor Multiple output in switch converter because of lower cost and smaller size. Thirdly, this paper took the single inductor double outputs as an example, analyzed DC-DC constant current driver. Due to the circuit needs feedback regulation, Peak current mode was used in the control circuit. At last, PID control was added in the compensating circuit to keep the circuit stable.This paper not only analyzed in theories but also made experiments; for one thing it used state-space average method to analyze the working condition and to derive the small signal average model in DCM mode, then analyzed peak current control mode and the stability after adding the PID module, and obtained the small signal block diagram with driving circuit and open-loop transfer function with the whole system, at last analyzed the stability with the whole open-loop and the closed-loop. For another it simulated the circuit and designed a model circuit to test the circuit. As non-isolated Boost Single inductor double outputs for example, explained the main circuit, control circuit and compensating circuit. Then tested the outputs voltages and currents, the results basically corresponded the hopes.更多还原