【作者】 王炜；

【导师】 陆生礼；

【作者基本信息】 东南大学 ， 微电子学与固体电子学， 2019， 硕士

【摘要】 目前开关电源正朝着高频小型化趋势发展,原边反馈反激谐振变换器具有电路结构简单,开关损耗小等优点,非常适用于高频的中小功率AC-DC电源。由于该变换器利用寄生参数谐振实现软开关控制,辅助绕组电压波形的不规则度増大,导致传统数字采样方法误差较大。因此,该结构变换器的高精度电压数字采样策略需要深入研究与优化。针对上述问题,本文设计了一种MHz级原边反馈反激单管谐振变换器的高精度数字采样策略。首先从主拓扑结构、原边数字采样技术、软开关控制三个角度介绍了数字采样技术的基本原理,在此基础上,主要完成了以下工作:(1)设计了适用于单管谐振反激变换器的原边数字采样策略;(2)分别设计了连续导通模式CCM和断续导通模式DCM下的双输出DAC拐点采样算法,以替代ADC副边直接采样,节约了采样电路成本;(3)设计了适用于CCM和DCM模式的高精度采样补偿算法,对采样电压进行修正补偿,从而实现了电压的精准恒压输出。根据所提出的算法,搭建了MATLAB-Simulink仿真平台,进行算法行为级仿真,利用MATLAB与Modelsim联合平台进行了RTL级仿真验证系统环路功能。最终设计主拓扑样机和控制板,基于FPGA硬件平台,实测验证了所设计的高精度数字采样算法的有效性。仿真和实测结果表明,本文所设计的双输出DAC拐点采样算法和采样误差补偿方案,在全负载输入电压范围内,采样电路的精度达到±1.4%,变换器系统的恒压精度为±1.67%,达到了设计要求。更多还原

【Abstract】 At present,the switching power supply is developing towards the trend of high frequency miniaturization.The primary feedback flyback resonant converter has the advantages of simple circuit structure and small switching loss,and is very suitable for high frequency medium and small power AC-DC power supplies.Since the converter realizes soft switching control by using parasitic resonance,the irregularity of the auxiliary winding voltage waveform is large,which leads to a large error with the conventional digital sampling method.Therefore,the high-precision voltage digital sampling strategy of this structure converter needs in-depth research and optimization.Aiming at the above problems,this thesis designs a high-precision digital sampling strategy for a MHz-level primary feedback flyback single-switched resonant converter.Firstly,the basic principles of digital sampling technology are introduced from three perspectives: main topology,primary digital sampling technology and soft switching control.On this basis,the following work is mainly done:(1)Designed for single-switched resonant flyback The primary side digital sampling strategy of the converter;(2)designed the continuous conduction mode(CCM)and the discontinuous conduction mode(DCM)dual output DAC inflection point sampling algorithm,which replaces the ADC directly sampling the output voltage,saving the cost of the sampling circuit;(3)Designed a high-precision sampling compensation algorithm suitable for CCM and DCM mode,correcting and compensating the sampling voltage,thus achieving accurate and constant voltage output of the voltage.According to the proposed algorithm,the MATLAB-Simulink simulation platform is built,and the algorithm behavior level simulation is carried out.The loop function of RTL level simulation verification system is carried out by using MATLAB and Modelsim joint platform.Finally,the main topology prototype and control board are designed.Based on FPGA hardware platform,the effectiveness of the designed high-precision digital sampling algorithm is verified.The simulation and measured results show that the double-output DAC inflection point sampling algorithm designed in this thesis has a precision of ±1.4% in the full load input voltage range and ±1.67% in the constant voltage accuracy of the converter system.更多还原