Modeling and Nonlinear Dynamic Analysis of Cascaded DC-DC Converter Systems Based on Simplified Discrete Mapping

• Published in: IEEE transactions on industrial electronics (1982) 2023-06, Vol.70 (6), p.5830-5839
• Main Authors: Cheng, Chao, Xie, Fan, Zhang, Bo, Qiu, Dongyuan, Xiao, Wenxun, Ji, Huayv
• Format: Article
• Language: English
• Subjects: Analytical models; Basic converters; Cascaded dc–dc converters; DC-DC power converters; discrete-time mapping (DTM) model; Dynamical systems; Load modeling; Mapping; Modelling; Nonlinear dynamics; Power system stability; stability analysis; state-space averaging model; Switches; Switching; Switching frequency; Thermal stability; Voltage converters (DC to DC)
• ISSN: 0278-0046; 1557-9948
• DOI: 10.1109/TIE.2022.3192684

As a basic structure of the distributed power systems, cascaded dc-dc converter systems have attracted a lot of attention. However, due to the interaction between the subconverters, classic methods for modeling cascaded systems are either not accurate enough, such as state-space averaging model, or not simple enough, such as discrete-time mapping model, especially the systems with different switching frequencies. To overcome this drawback, a simplified discrete-time mapping modeling method for cascaded dc-dc converter systems is proposed in this article. Based on the idea of state-space average, the original problem is simplified to modeling cascaded dc-dc converter systems with the same switching frequencies. The proposed method is able to predict the dynamic properties of the system at all stages, such as slow-scale and fast-scale instabilities. Then, two-stage cascaded boost converter with different switching frequencies under peak current double loop control is taken as an example to present the simplified discrete-time mapping model. Finally, the effectiveness of the proposed method is verified by simulations and experiments.