一种用于机载电子设备的DC-DC开关电源的设计与实现

发布时间：2018-03-14 15:52

本文选题：机载电源　切入点：GJB151A　出处：《电子科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：开关电源由于具有体积小、效率高、成本低等优点被广泛用于机载电子设备中使用,而实际飞机供电存在过压浪涌、欠压浪涌、瞬时供电中断等情况,同时开关电源本身在工作过程中会产生电磁噪声,对机载敏感用电设备造成影响,为此机载电源必须满足GJB181A飞机供电特性和GJB151A电磁兼容的相关规定。本文设计和实现一种小体积、宽输入电压、高效率、50ms掉电维持、低纹波和满足电磁兼容的多路DC-DC输出机载开关电源,论文主要研究内容和成果如下:1.针对小体积、宽输入电压要求,对比研究不同的拓扑结构最终确定单端反激结构实现4路DC-DC小型化设计。重点对单端反激变压器的设计及外围PWM反馈控制、电流采样、斜坡补偿和RCD吸收电路等进行研究,结合50ms掉电维持电路设计使得输入电压宽达10V~50V。2.针对高效率要求,研究开关电源中的损耗组成和影响因素以指导电路设计和元器件选型。研究单端反激同步整流结构和跳频控制模式Buck供电电路,最终实现总功率33W效率高达到85%的电路设计。3.针对50ms掉电维持和12V电启动要求,提出基于钽电容储能,采用充电电路→储能电容→放电电路的结构实现电路设计。该方法大大降低了储能电容容量、体积和成本,同时通过控制占空比实现了充电浪涌电流限制。研究了电容放电结束时输出振荡的现象并设计宽滞回电压欠压保护电路进行控制。放电电路的升降压特性实现了12V电启动,最终电路浪涌电流仅为0.5A,充电时间小于3s,断电维持无输出振荡现象。4.针对低输出纹波和电磁兼容要求,对纹波形成机理,多路输出窜扰、拍频干扰影响因素进行研究并提出滤波、接地等措施;分析了开关电源中的主要噪声干扰源和EMI滤波器原理,对共模干扰和差模干扰的流动路径和EMI滤波器的等效电路进行了研究,采用对比试验的方法设计EMI滤波器的参数。最终产品纹波小于20mV,通过了电磁兼容试验。论文还从可靠性角度进行了输出过压、状态指示等保护功能电路的设计和仿真,并进行了降额、热设计、结构设计和容差分析等可靠性设计,最终实现高可靠机载开关电源的研制。
[Abstract]:Switching power supply with small volume, high efficiency and low cost has been widely used for airborne electronic equipment, and the actual existence of aircraft power supply overvoltage surge, undervoltage surge, instantaneous power interruption, and switching power supply itself in the work process will produce electromagnetic noise for airborne sensitive electrical equipment caused by the impact, so Airborne the power supply must meet the relevant provisions of the aircraft power supply characteristics and GJB151A electromagnetic compatibility GJB181A. We design and implement a small volume, wide input voltage, high efficiency, low ripple 50ms power down to maintain, and meet the multi-channel DC-DC output switching power supply of airborne magnetic compatibility, the main research contents and results are as follows: 1. for small volume, wide the input voltage requirements, comparison of different topologies and ultimately determine the implementation of single end flyback structure 4 DC-DC miniaturization design. Focus on the single end flyback transformer design and The peripheral PWM feedback control, current sampling of slope compensation and RCD absorption circuit, power circuit design combined with 50ms to maintain the input voltage up to 10V~50V.2. wide for high efficiency, composition and effect of loss factor in the switching power supply in order to guide the circuit design and component selection of single ended flyback synchronous rectifier and frequency hopping control structure Buck mode power supply circuit, finally realizes the circuit design of.3. 33W total power efficiency reached 85% for 50ms and 12V electric power down to maintain the starting requirements, proposed based on the tantalum capacitor, charging circuit, energy storage capacitor structure, discharge circuit circuit design. This method greatly reduces the storage capacity, size and at the same time cost by controlling the duty cycle for the charging inrush current limiting. At the end of the capacitor discharge output oscillation phenomenon and design of wide hysteresis voltage undervoltage protection The control circuit of the discharge circuit protection. The lifting pressure characteristics of the 12V electric start, the final circuit surge current is only 0.5A, the charging time is less than 3S, no output power to maintain oscillation of.4. for low output ripple and electromagnetic compatibility requirements, the formation mechanism of multi output ripple, crosstalk, on beat interference factors and propose filtering, grounding measures; analysis of the switching power supply in the main noise source and the principle of EMI filter, the equivalent circuit of the common mode interference and differential mode interference flow path and EMI filter are studied, the parameters of design than the test method of EMI filter. The final product ripple is less than 20mV, through the electromagnetic compatibility from the perspective of reliability test. The paper also makes the output overvoltage, circuit design and simulation function of state indication protection, and by reducing the amount of thermal design, analysis, structure design and tolerance And so on reliability design, and finally realize the development of high reliable airborne switching power supply.

【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：V243

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