4VA直流高频开关电源设计.docVIP

摘 要 目前开关电源向着高频高可靠低耗低噪声抗干扰和模块化Abstract At present, the switching power supply developed high frequency, high reliability, low energy consumption, low noise, interference and modular direction. That is to develop the inverter power source controlled by microcomputer which adopts soft-switches . This researching task is put forward on the base of discussing the characteristics and virtues of the welding inverter. The phase-shift chip UC3875 is adopted phase-shift pulse width modulate. The design about high frequency transformer is given .The amplified circuit and the commuted circuit are designed. The paper mostly researches and designs the soft-switch control system. Secondly, the control circuit, the protect circuit of the power supply are analyzed and designed. Its control circuit is centered on UC3875, uses a control that based regulation to realize the function is composed of analog of voltage-stabilization and current-limited. In addition, the safeguard circuit that mainly consists of over current, over heat, over voltage and circuit are studied and designed in the paper. And the circuit is simulated by the SABER, Simulation results show that the design is correct. Key words: soft-switch, UC3875, phase-shift目 录 摘 要 I Abstract II 目 录 III 第一章 引 言 1 1.1开关通信电源系统的介绍 1 1.1.1通信设备对开关通信电源的要求 1 1.1.2通信电源系统的组成 2 1.2通信直流开关电源的发展现状和发展方向 2 1.2.1开关电源的发展和趋势 2 1.2.2软开关技术的发展 3 1.3本文的主要工作 4 第二章 高频开关电源主电路的设计与实现 6 2.1高频开关电源的技术指标 6 2.2高频开关电源主电路的硬件设计 6 2.2.1输入整流电路的设计 6 2.2.2直流变换器的设计 7 2.2.3输出整流电路的设计 8 2.3移相全桥谐振软开关电路[2][3][7] 9 2.3.1移相全桥零电压PWM软开关电路的工作原理 9 2.3.2移相零电压软开关电路存在问题的解决 11 2.3.3 ZVS的实现及副边占空比丢失 12 2.3.4 结论 13 2.4主电路元件参数的选择 14 2.4.1 输入电路参数的选择[8] 14 2.4.2高频变压器的设计[1] 15 2.4.3输出滤波电感的设计 17 2.4.4输出滤波电容的选择 17 2.4.5 吸收电路器件的选择 18 2.4.6功率器件的选择 19 2.5本章小结 19 第三章 高频开关电源控制电路的硬件设计与实现 21 3.1移相控制芯片UC3875的概述 21 3.3.1 UC3875电气特性 21 3.1.2 UC3875外围电路的设计 22 3.1.3 UC3875输出波形的分析 25 3.1.4 光电耦合器 26 3.2保护电路的设计 26 3.2.1电压与电流的保护 27 3.2.2过热保护电路 28 3.3 辅助电源设计 28 3.4 本章小结 29 第四章 电路的仿真及分析 30 结 论