【作者】 陆莹；

【导师】 许维胜；

【作者基本信息】 同济大学 ， 控制理论与控制工程， 2007， 硕士

【摘要】 随着半导体材料的发展，高功率白光LED成为许多领域照明的首选器件，是新世纪“绿色照明”的主力军。LED需要低电压、大电流进行供电。而且随着LED灯具功率的提升，直接交流电输入正成为LED驱动的必要要求。因此本课题针对该需求，期望设计出直接交流电输入、具备功率因数校正功能及恒流输出的开关变换器为高功率照明用LED供电。该变换器也适合于中小功率的大电流驱动场合，例如微处理器的供电。根据这样的设计思路，本文主要完成了以下工作：1．通过大量阅读文献和方案对比，确定了课题的技术实现方案。采用单周期控制技术令对偶Boost变换器工作在电容电压连续模式。对偶Boost变换器与传统Boost电路结构对偶，与带输入滤波器的Buck变换器具有相同的电路结构，能实现“升流”功能。电容电压连续模式保证变换器输入电压、电流均连续变化，避免了Buck变换器输入电流断续的缺点。单周期控制避免使用乘法器等昂贵元件即可实现给定的快速跟踪和功率因数校正。2．使用三段频率法建立了变换器控制系统的完整模型。整个系统由工作在开关频率的电压前馈环和工作在2倍线频率的电流反馈环组成。电压前馈环使得输入电压总是跟踪输入电流，从而实现功率因数校正。电流反馈环确保输出电流稳定。建立了前馈控制-输出、反馈控制-输出、输入扰动-输出、负载扰动-输出的传递函数，在这一过程中通过分析得到了保证系统稳定性的参数必要条件。3．利用MATLAB和Saber Designer分别进行了系统的频域和时域仿真。参数整定后，利用MATLAB分析了电流外环的开环频率特性，并针对其频率特性设计了误差放大器(补偿环节)。利用Saber Designer提供的多种分析功能，完成了课题提出的变换器的时域功能验证。通过仿真验证最终得到结论：课题所提出的变换器输出恒流满足设计要求、启动过程平滑、开关管承受压力小、输入电流与输入电压相位同步，但输入电流畸变较严重、功率级使用电感更大。更多还原

【Abstract】 With the development of semiconductor materials, high power LED (Light Emmiting Diode) becomes the first choice for many lighting applications, and is the main force of New Century’s Green Lighting project. LEDs require low voltage, high current drivers. And along with increasing of driving power, adding direct alternative current input to LED drivers becomes urgent. Thus a novel power factor corrector with direct AC line voltage input and constant current output is proposed in this thesis.According to above design goals, authur’s main work lies in:1. By reading a great quantity of in-art articles and comparing existing solutions, a better solution comes out: One-Cycle controlled Dual boost converter working in Continuous Capacitor Voltage Mode (CCVM). Dual Boost has the same topology as traditional buck converter with input filter, which could "Boost" the current. CCVM guarantees the continuous input voltage and current, which avoid the "discontinuous input current" drawback of buck converter. One-Cycle control needs no multiplier to accomplish power factor correction and fast output regulation.2. To model the converter system with Three-Bandwidth Analysis. the whole system is consisted of switching frequency voltage feedfaword loop and line frequency current feedback loop. The former makes input voltage track input current, thus power factor correction. The latter guarantee a constant output current. Feedfaword-control, feedback-control, input disturbance-output, load disturbance-control transfer functions are established, meanwhile stability requirements for circuit components are given out in this part.3. To simulate frequency domain and time domain response with MATLAB and Saber Designer, respectively. After calculation of circuit components, MATLAB simulation result helps to settle error amplifier (the PI compensator). Saber Designer’s many analysis functions, such as DC, Transient, Vary, Monte Carlo analysis, time domain verification of converter function is achieved. Through analysis, simulation and verification, the conclusions come out: proposed converters have intrinsit output current regulation; input current has the same phase with input voltage; soft start and low switch stresss during start-up etc. However, simulation results show that input current distortion is severe, and inductance in power stage is higher than other topologies.更多还原