LLC谐振变换器滞环控制数字实现与对比  

Digital Realization and Comparison for Hysteretic Control of LLC Resonant Converter

作　　者：谢维 李大伟 刘斌 王许成 XIE Wei;LI Da-wei;LIU Bin;WANG Xu-cheng(HUADA SEMICONDUCTOR Co.,Ltd.,Shanghai 201200,China)

机构地区：[1]华大半导体有限公司,上海201200

出　　处：《电力电子技术》2023年第2期105-109,共5页Power Electronics

摘　　要：传统的LLC变换器数字控制通常采用脉冲频率调制(PFM)或平均电流控制,但其存在控制补偿环路参数设计困难,动态性能差等缺点。此处提出一种基于数字实现的LLC滞环控制完整方案,包括基于精确稳态工作点的滞环控制建模,从而实现精确的系统控制环路参数设计,基于窄采样范围的开环启动方案,使得在满足系统控制精度的条件下,也能实现快速平滑启动,基于捕获开关管导通时间的占空比不对称补偿方案,保证谐振腔电流对称,变压器可靠运行;最后针对burst模式下变压器噪音问题,提出轻载控制及其切换优化策略。为了验证所提滞环控制方案的可行性与有效性,搭建了一台额定功率为1.6 kW的半桥LLC谐振变换器实验平台,并与传统控制方案进行对比分析,结果表明,相对于传统数字控制方案,所提滞环控制完整方案在瞬态响应方面具有更好的性能。The traditional digital control of LLC converters usually adopts pulse frequency modulation(PFM) control or average current control schemes,but it has some disadvantages such as difficult to design control parameters of compensation loop and poor dynamic performance.A complete LLC scheme of hysteretic control based on digital realization is proposed,including the modeling of hysteretic control based on precise steady-state operating point which achieve the precise design of system control loop parameters,the open-loop start-up scheme based on narrow sampling range,which can implement fast and smooth start with satisfying the condition of system control precision.The duty cycle asymmetric compensation scheme based on capturing switch conduction time which can ensure the symmetry of resonant current and the reliable operation of transformer.Finally,aimiting at the transformer noise in burst mode,a light load control and its switching optimization strategy is proposed.An experimental platform of half-bridge LLC resonant converter with rated power of 1.6 kW is built to verify the feasibility and effectiveness of the proposed digital control scheme,and to compare it with the traditional control schemes.The results show that compared with the traditional digital control scheme,the proposed hysteretic control scheme has better performance in transient response.

关 键 词：变换器 滞环控制 数字实现 瞬态响应 

分 类 号：TM46[电气工程—电器]