飞跨电容型三电平Buck变换器双闭环控制研究  

Research on double closed loop control of flying-capacitor three-level Buck converter

作　　者：韩锟[1] 马晓慧 李蔚[1] HAN Kun;MA Xiaohui;LI Wei(School of Traffic&Transportation Engineering,Central South University,Changsha 410075,China)

机构地区：[1]中南大学交通运输工程学院,湖南长沙410075

出　　处：《铁道科学与工程学报》2025年第2期829-840,共12页Journal of Railway Science and Engineering

基　　金：广西科技重大专项资金资助项目(桂科AA20302010)。

摘　　要：飞跨电容型三电平Buck变换器因具有输出电压电流谐波小、开关管电压应力小等优势在轨道交通储能系统中被广泛应用。为保证其中点电位平衡的同时提高其输出电流、电压品质,在对输出电压与飞跨电容电压解耦的基础上提出一种模型预测控制与自抗扰控制相结合的双闭环控制方法。电流内环采用引入飞跨电容电压调节速率因子的连续集模型预测控制策略,该方法开关频率固定,不需要调节评价函数的权重系数,能降低控制器设计难度,通过微调开关管占空比实现对外恒流充电工况和中点电位平衡控制,利用李雅普诺夫理论分析了内环的稳定性。电压外环采用基于粒子群参数寻优的自抗扰控制器,实时估计并补偿负载突变等扰动,改善系统的抗扰能力,满足对外恒压充电工况的需求。这种双闭环结构限制了变换器最大峰值电流,保证了变换器可靠运行。在50 kHz开关频率下进行仿真和半实物实验,结果表明所提控制策略将飞跨电容电压稳定在输入电压的一半,保证了中点电位平衡,在此基础上实现了恒流和恒压输出。其中,对于输出电流单环控制,模型预测控制与PI控制器相比表现出更快的响应速度;对于电压电流双闭环控制,所提控制策略的响应时间比PI双闭环控制提升了44%,当输入电压和负载电阻发生突变时,所提控制策略与PI控制相比输出电压超调量更小、调节时间更短。Flying-capacitor three-level Buck converter has been widely used in rail transit charging system because of its low output voltage,current harmonics,and low voltage stress of switching tube.To enhance the control quality of the output current and voltage,while maintaining neutral-point potential balance,a dual closed loop method that combines model predictive control with active disturbance rejection control was proposed,based on the decoupling of output voltage and flying capacitor voltage.The current inner loop adopted a continuous set model predictive control with the introduction of the flying capacitor voltage regulation rate factor.The switching frequency of this method was fixed,and the weight coefficient of the evaluation function does not need to be adjusted,which reduces the difficulty of controller design.The external constant current charging condition and midpoint potential balance control were realized by fine tuning the duty ratio of the switching tube.The stability of the inner loop was analyzed by using Lyapunov theory.The active disturbance rejection control based on particle swarm parameter optimization was used in the voltage outer loop to estimate and compensate the disturbance such as sudden load change in real time,which improved the immunity of the system and meets the demand of external constant voltage charging conditions.The double closed-loop structure limited the maximum peak current of the converter and ensured the reliable operation of the converter.At 50 kHz switching frequency,simulation and semi-physical experiments were carried out.The results show that the proposed control strategy can stabilize the flying-span capacitor voltage at half of the input voltage and ensure the balance of midpoint potential.On this basis,constant current and constant voltage output were realized.For the output current single loop control,the model predictive control has a faster response speed than PI controller.For the voltage-current double closed loop control,the response time of the proposed cont

关 键 词：飞电容三电平降压变换器 解耦控制 模型预测控制 最优控制律 自抗扰控制 

分 类 号：TM46[电气工程—电器]