摘要
级联DC-DC变换器结构是直流分布式电源系统的常用形式,级联系统中单独设计的单个变换器能够独立稳定运行,但级联后因源和负载变换器间相互作用可能引起整个系统的不稳定。该文以Buck变换器级联为例,通过状态空间平均法建立大信号模型分析级联系统的开环稳定性,并据此确定能在全负载范围内稳定的并联电阻范围;然后分析并联电阻对级联系统中源变换器输出阻抗影响,在此基础上提出一种基于并联虚拟电阻的有源阻尼控制策略,以改善级联系统的稳定性。该方法可在不影响源变换器的闭环动态性能下,满足与负载变换器输入阻抗相匹配的稳定要求。然后利用Lyapunov间接法得到该控制策略的稳定性判据,通过合理选择并联虚拟电阻可满足整个系统稳定。最后通过仿真和实验证了所提控制策略的有效性。
Cascaded DC-DC converter structure is a common form of DC distributed power systems.A converter designed individually can operate independently and stably.However,it may cause the instability of the whole system due to the interaction between the source and load converter after cascading.In this paper,a cascaded buck converter is taken as an example.The large-signal model is established by state space average method to analyze the open-loop stability of the cascaded system,and the parallel resistance range that can be stable in the full load range is derived.Then the influence of the resistance on the close-loop output impedance of the source converter is analyzed.Accordingly,an active damping control strategy based on paralleling virtual resistor is proposed to improve the stability of the cascaded system.This strategy can meet the stability requirement of matching the input impedance of the load converter without affecting the closed-loop dynamic of the source converter.The Lyapunov indirect method is used to analyze the stability conditions of the control strategy.The reasonable selection of the paralleling virtual resistor can satisfy the stability of the whole system.Finally,the effectiveness of the proposed control strategy is verified by simulation and experiment.
作者
黄远胜
刘和平
苗轶如
廖建权
Huang Yuansheng;Liu Heping;Miao Yiru;Liao Jianquan(State Key Laboratory of Power Transmission Equipment&System Security and New Technology Chongqing University,Chongqing 400044 China)
出处
《电工技术学报》
EI
CSCD
北大核心
2020年第18期3927-3937,共11页
Transactions of China Electrotechnical Society
基金
国家自然科学基金面上资助项目(51877017)。
