Z-domain modeling of peak current mode control for full-bridge DC-DC buck converters

Abstract

Traditional local-averaged state-space modeling for peak current mode (PCM) controls fails to explain the subharmonic oscillation phenomenon when the spectrum is higher than half of the switching frequency. To address this problem, this paper presents a small-signal modeling method in the z-domain, and builds a discrete linear model for the current loop of a full-bridge DC-DC converter. This discrete model is converted into a second-order continuous model that is able to represent the system performance with a wider frequency range. A frequency-domain analysis shows that this model can be used to explain the subharmonic oscillations and unstable characteristics. This provides an engineering guideline for the practical design of slope compensation. The effectiveness of the proposed modeling method has been verified by simulation and experimental results with a prototype working in the Buck mode.

Ankastre Bir Kirişin Ayrık Zamanlı Titreşim Modelinin Meta-sezgisel Optimizasyon Yöntemleri Kullanılarak Elde Edilmesi

“…Oluşturulan modellere çeşitli giriş sinyalleri uygulanarak sistem davranışı gözlenebilmekte ve gerekliyse aktif kontrolör tasarlanmasında bu modeller kullanılmaktadır [6]. Günümüzde mikroişlemci teknolojisindeki gelişmeler sebebiyle mühendislik sistemlerinin modellenmesi ayrık zamanlı modeller şeklinde de yapılmaktadır [7].…”