隔离型有源钳位AC-DC变换器多模式原边反馈数字控制策略研究

Isolated active-clamp AC-DC converter can realize high frequency, high power, small volume and electronic isolation, thus it can be used in power adapters of mobile devices such as cell phones and table tablets. As opto-coupler is used in the feedback control loop, aging effect, temperature-drift effect and limited working temperature are introduced. Primary-side regulation control method is aimed to remove the opto-coupler and improve the working performance of the converter. However, due to the non-linearity and simple control method, the existing research can not satisfy the requirements of the output precision, the efficiency and the dynamic transition. To solve the above problems, this project will focus on the study of primary-side control of active-clamp converter. Considering the non-linearity and the parasitic parameters, the precise sampling model, loss model and circuit model under different control mode are firstly established. Based on the models, constant voltage and current realization with primary-side regulation control, multimode control method with efficiency optimization and stable closed loop control with fast dynamic performance will be developed. At last, an isolated active-clamp AC-DC converter featuring high efficiency, high accuracy and rapid dynamic response will be acquired. This project will promote the technology development of power improvement and volume reduction in isolated AC-DC converter. It will also provide theoretical guidance for the design of this kind of converter and the control chip.

隔离型有源钳位AC-DC变换器具有高频率、高功率、小体积及安全可靠的特性，在手机、笔记本电脑等智能移动设备电源中得到了较多应用。当前该变换器采用光耦反馈电路，存在老化、温漂及工作温度受限等问题，原边反馈控制方案旨在移除光耦器件，提升变换器性能。然而变换器存在非线性特性及寄生效应，且控制方式单一，当前研究方案无法满足变换器对输出精度、转换效率及环路动态调节等性能的需求。针对以上问题，本项目将综合考虑变换器非线性特性与寄生效应，建立不同工作模式下原边反馈控制的精确采样模型、损耗模型与环路频域模型，从而分别研究原边反馈高精度恒压、恒流控制方法，优化整体效率的自适应多模式控制方法与提高动态调节的环路控制方法，最终得到高精度、高效率、高动态响应隔离型有源钳位AC-DC变换器稳定的多模式原边反馈数字控制策略。本项目将推动隔离型AC-DC变换器高功率、小体积技术发展，并为该类电源及芯片设计提供理论指导。