Sampled-Data Modeling and Analysis of Closed-Loop PWM DC-DC Converters
Abstract
Sampled-data analysis of converters has been a topic of investigation for the past two decades. However, this powerful tool is not widely used in control loop design or in closed-loop performance validation. Instead, averaged models are typically used for control loop design, while detailed simulations are used for validating closed-loop performance. This paper makes several contributions to the sampled-data modeling and analysis of closed-loop PWM DC-DC converters, with the aim of increasing appreciation and use of the method. General models are presented in a unified and simple manner, while removing simplifying approximations present in previous work. These models apply both for current mode control and voltage mode control. The general models are nonlinear. They are used to obtain analytical linearized models, which are in turn employed to obtain local stability results. Detailed examples illustrate the modeling and analysis in the paper, and point to situations in which the sampled-data approach gives results superior to alternate methods. For instance, it is shown that the sampled-data approach will reliably predict the (local) stability of a converter for which averaging or simulation predicts instability.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1999
- Accession Number
- ADA438679
Entities
People
- Chung-chieh Fang
- Eyad H. Abed
Organizations
- University of Maryland