峰值电流控制Buck变换器高频建模及结合遗传算法的控制器优化设计  

High-Frequency Modeling for Peak Current-Model Buck Converters and Optimal Controller Design by Combining Genetic Algorithm

作　　者：程翔鹏 刘进军[1] 邵钰 刘增[1] Cheng Xiangpeng;Liu Jinjun;Shao Yu;Liu Zeng(State Key Laboratory of Electrical Insulation and Power Equipment Xi’an Jiaotong University,Xi’an 710049,China)

机构地区：[1]电力设备电气绝缘国家重点实验室(西安交通大学),西安710049

出　　处：《电工技术学报》2024年第1期217-232,共16页Transactions of China Electrotechnical Society

基　　金：国家自然科学基金资助项目(51437007)。

摘　　要：峰值电流控制Buck变换器广泛应用于电源管理芯片。小信号建模是设计其控制器的关键。现有模型忽略电压外环引入的稳态控制信号纹波与小信号扰动延拓频谱对系统的影响,在高控制带宽场景下失效,从而无法指导控制器的设计。该文首先指出控制器设计决定了控制信号纹波类型,进而研究了可导型纹波对系统建模的影响;然后综合考虑电压、电流环导致的频谱耦合,得到精确的高频模型;最后基于高频模型,提出一种结合遗传算法的高带宽控制器优化设计方法。仿真与实验证明了该模型的精确性与设计方法的优越性。Peak current-model(PCM)Buck converters are widely employed in power management ICs.As microprocessors integrate continuously,high-bandwidth design has become a requisite for the front-end Buck converters.Accurate small-signal modeling is crucial for analyzing system stability and designing high-performance controllers.Existing models neglect control signal ripples(CSRs)in steady-state and extended-spectrum under small-signal perturbation transferred by voltage-loop,which makes significant errors under high control bandwidth and fails to guide controller design.To portray the high-frequency characteristics of the system and direct the design of high-bandwidth controllers,this paper proposed a high-frequency model for PCM Buck converters.An optimal controller design method was conducted based on the proposed model and genetic algorithm.Firstly,this paper emphasized that different types of CSRs are initiated by different types of controllers.Subsequently,influences caused by differentiable CSRs were analyzed,wherein the impact of differentiable ripples on the system can be equivalent to the derivative values at crossing points.The spectrum coupling from the voltage-loop and current-loop was incorporated,and the maximum frequency point corresponding to-20 dB amplitude of the single-frequency loop gain was taken as the selection boundary of the extended spectrum to simplify the model.Thereby an accurate small-signal model was obtained.Analytical expressions for loop gain,audio susceptibility,input impedance,and output impedance were derived based on matrix operations.Lastly,based on the proposed high-frequency model,an efficient optimization design of high-bandwidth controllers was conducted by combining genetic algorithm.To assert the accuracy of the proposed model and the effectiveness of the optimal controller design method,this paper devised two cases and conducted simulations and experimental verifications.For caseⅠ,the loop gain predicted by the proposed model(Bandwidth:222.5 kHz,Phase margin:29.9°)matches we

关 键 词：BUCK变换器 峰值电流控制 高带宽 高频建模 遗传算法 

分 类 号：TM46[电气工程—电器]