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Lookup NU author(s): Dr Haimeng Wu,
Professor Volker Pickert,
Dr Xu Deng,
Dr Damian Giaouris,
Dr Wei Li
This is the authors' accepted manuscript of an article that has been published in its final definitive form by IEEE, 2019.
For re-use rights please refer to the publisher's terms and conditions.
Abstract: Linear Ramp Slope Compensation (LRC) and Quadratic Slope Compensation (QSC) are commonly implemented in peak current mode controlled DC-DC converters in order to minimize subharmonic and chaotic oscillations. Both compensating schemes rely on the linearized state-space averaged model (LSSA) of the converter. LSSA ignores the impact that switching actions have on the stability of converters. In order to include switching events, the nonlinear analysis method based on Monodromy matrix was introduced to describe a complete-cycle stability. Analyses on analogue controlled DC-DC converters applying this method show that system stability is strongly dependent on the change of the derivative of the slope at the time of switching instant. However, in a mixed-signal controlled system, the digitalization effect contributes differently to system stability. This paper shows a full complete-cycle stability analysis using this nonlinear analysis method, which is applied to a mixed-signal controlled converter. Through this analysis, a generalized equation is derived that reveals for the first time the real boundary stability limits, for LRC and QSC. Furthermore, this generalized equation allows the design of a new compensating scheme which is able to increases system stability. The proposed scheme is called Polynomial Curve Slope Compensation (PCSC) and it is demonstrated that PCSC increases the stable margin by 30% compared to LRC and 20% to QSC. This outcome is proved experimentally by using an interleaved DC-DC converter that is built for this work.
Author(s): Wu H, Pickert V, Deng X, Giaouris D, Li W, He X
Publication type: Article
Publication status: Published
Journal: IEEE Transactions on Industrial Electronics
Print publication date: 01/01/2019
Online publication date: 12/04/2018
Acceptance date: 02/04/2018
Date deposited: 08/04/2018
ISSN (print): 0278-0046
ISSN (electronic): 1557-9948
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