Affiliation of Author(s):自动化学院
Journal:IEEE TRANSACTIONS ON POWER ELECTRONICS
Key Words:Averaged model discrete-time model leading edge pulse width modulation (PWM) stability trailing edge
Abstract:For dc-dc converters with pulsating output current, such as boost and buck-boost converters, the use of leading-edge or trailing-edge pulse width modulation (PWM) can result in distinctly different behavior. This phenomenon is not readily captured by the usual averaged model but can be predicted with a discretetime model. However, the discrete-time model, which tracks the dynamics of state variables over a switching period, is usually more complex and less convenient to apply for the design of the feedback control. Based on the low-pass characteristics of dc-dc converters, an approximate discrete-time model is proposed in this paper, and upon transforming to the s-domain, the model results in transfer functions that can be conveniently used for deriving practical closed-loop parameters. With the proposed model, the loop gain, the input and output impedances are derived and analyzed. The effects of applying different types of PWM on the stability of a single dc-dc converter and a system of cascaded dc-dc converters are discussed. Finally, prototypes of a buck converter, a boost converter, and a cascaded system of buck and boost converters are constructed to verify the effectiveness of the approximate discrete-time model.
ISSN No.:0885-8993
Translation or Not:no
Date of Publication:2018-08-01
Co-author:李鑫,Li Xin,Jin, Qian,Sha, Mengke,Tse, Chi K.
Correspondence Author:rxb
Date of Publication:2018-08-01