采用开关电感的Buck变换器CCM和DCM特性分析  

Characteristics Analysis of Buck Converter with Switched Inductor in CCM and DCM

作　　者：祁静静 吴学智[1] 王久和[2] 续文政[1] 刘京斗[1] Qi Jingjing;Wu Xuezhi;Wang Jiuhe;Xu Wenzheng;Liu Jingdou(National Active Distribution Network Technology Research Center Beijing Jiaotong University,Beijing 100044,China;School of Automation Beijing Information Science and Technology University,Beijing 100192,China)

机构地区：[1]北京交通大学国家能源主动配电网技术研发中心,北京100044 [2]北京信息科技大学自动化学院,北京100192

出　　处：《电工技术学报》2022年第16期4155-4168,共14页Transactions of China Electrotechnical Society

基　　金：中央高校基本科研业务费专项资金资助项目(2020YJS168)。

摘　　要：Buck型DC-DC变换器采用开关电感单元后能拓宽电压变换范围且减小器件电流应力,但该文经推导发现,因电感的串并联切换会使等效电流分别为单电感电流的一倍和两倍,导致与负载电流的关系不确定,并使变换器变为非最小相位系统。该文以开关电感Buck变换器(SLBC)为例,在分析工作原理的基础上,指出该变换器在连续导通模式(CCM)下开关电感单元电流与负载电流间存在六种与电感和占空比密切相关的匹配关系,同时存在负调现象。在断续导通模式(DCM)下开关电感单元电流与负载电流间仅存在一种对应关系,且不存在负调现象。该文分别在CCM和DCM下使用状态空间平均法和全阶模型面积法建立SLBC的小信号模型,表明该变换器存在右半平面零点(RHPZ),系统特性类似于升压型DC-DC变换器。依据六种电流关系和RHPZ相对位置,给出电感、电容值的最佳选择区域,综合满足稳态纹波和动态响应需求。最后通过实验验证了该文理论分析的正确性。Buck DC-DC converters with switched inductor can broaden the voltage conversion range and reduce the device current stress. However, in this paper, it is found that the series-parallel switching of the switched inductor unit will make the equivalent current equal to or twice the single inductor current, resulting in an uncertain relationship with the load current and making the converter a non-minimum phase system. Taking the switched inductor Buck converter(SLBC) as an example,based on the operation principle, it is pointed out that there are six matching relationships between the switched inductor unit current and the load current in the continuous conduction mode(CCM), which are closely related to the inductance & duty cycle and affect the output voltage ripple, and there is also a negative regulation phenomenon. In the discontinuous conduction mode(DCM), there is only one correspondence between the switched inductor unit current and the load current, and there is no negative regulation phenomenon. The small signal model of the SLBC is established using the conventional state-space averaging method and the full-order model area method in the CCM and the DCM respectively. It is shown that the RHPZ exists in this converter and the system characteristics are similar to a step-up DC-DC converter. Based on the six matching relationships and the relative position of the RHPZ, the best selection area of inductance and capacitance is given to meet the requirements of steady-state ripple and dynamic response comprehensively. Finally, the correctness of the analysis in this paper is verified by experiments.

关 键 词：开关电感 BUCK 小信号建模 右半平面零点 参数设计 

分 类 号：TM46[电气工程—电器]