Stability analysis of digitally controlled dual active bridge converters

• 作者: Jun HUANG Ling SHI Wanjun LEI Yao CUI Yue WANG Zhuoqiang LI
• 来源期刊: 现代电力系统与清洁能源学报(英文)
• 学科: 工学
• 关键词: DUAL ACTIVE bridge(DAB) DISCRETE time modeling Stability analysis Dynamics
• 年，卷（期）: 2018,（2）
• 页码范围: 375-383
• 页数: 9页
• 分类号: TM46

摘要

The dual active bridge(DAB) converters are widely used in the energy storage equipment and the distributed power systems. However, the existence of switching nonlinearity and control delay can cause serious stability problem to the DAB converters. Thus, this paper,studies the stability of a digitally controlled DAB converter with an output voltage closed loop controller. Firstly, to accurately study the stability in a DAB converter, a discrete-time model established in a whole switching period is obtained. The model considers the output capacitor ESR,the digital control delay, and sample-and-hold process. By using this model, the stabilities of the DAB converter versus the proportional controller parameter and the output capacitor ESR are analyzed and the critical values are predicted accurately. Moreover, the stability boundary ofthe proportional controller parameter and the output capacitor ESR is also obtained. The result shows that the value of the output capacitor ESR can have a great effect on the stability region of the proportional controller parameter. Finally, the theoretical analyses are verified by the simulation and experimental results.