scholarly journals Small-signal input characteristics of step-down and step-up converters in various conduction modes

2016 ◽  
Vol 64 (2) ◽  
pp. 265-270 ◽  
Author(s):  
W. Janke ◽  
M. Walczak
Keyword(s):  
Low Frequency ◽  
Laboratory Model ◽  
Small Signal ◽  
Input Admittance ◽  
Discontinuous Conduction Mode ◽  
Dc Power ◽  
Signal Input ◽  
Analytical Formulas ◽  
Averaged Models ◽  
Conduction Mode

Abstract Small-signal input characteristics of BUCK and BOOST DC-DC power converters in continuous conduction and discontinuous conduction mode have been presented. Special attention is paid to characteristics in discontinuous conduction mode. The input characteristics are derived from the general form of averaged models of converters. The frequency dependence of input admittance and other input characteristics has been observed in a relatively low-frequency range. The analytical formulas derived in the paper are illustrated by numerical calculations and verified by experiments with a laboratory model of BOOST converter. A satisfying level of conformity of calculations and measurements has been obtained.

scholarly journals A New Buck-Boost AC/DC Converter with Two-Terminal Output Voltage for DC Nano-Grid

Energies ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3808 ◽  
Author(s):  
Xiangkun Li ◽  
Weimin Wu ◽  
Houqing Wang ◽  
Ning Gao ◽  
Henry Shu-hung Chung ◽  
...  
Keyword(s):  
Steady State ◽  
Output Voltage ◽  
Operating Principle ◽  
Small Signal ◽  
Grid System ◽  
Power Sources ◽  
Steady State Analysis ◽  
Dc Power ◽  
Signal Modelling ◽  
Conduction Mode

Due to the development and deployment of renewable DC power sources and their inherent advantages for DC loads in applications, the DC nano-grid has attracted more and more research attentions; especially the topologies of AC/DC converters are increasingly studied. When designing an AC to DC converter for a DC nano-grid system, the grounding configuration, which determines the costs, the efficiency as well as the safety, plays an important role. A three-terminal output AC to DC converter based on united grounding configuration has been presented for DC nano-grid. However, it has to be pointed out that the three-terminal output DC nano-grid is not as popular as the two-terminal DC output one, due to the infrastructure consideration. This paper proposes a new Buck-Boost AC to DC converter with two-terminal output voltage for DC nano-grid. The operating principle, the steady-state analysis, and the small signal modelling for the proposed converter working in continuous conduction mode are presented in detail. A 220 V/50 Hz/800 W prototype was fabricated to verify the effectiveness of the proposed converter.

scholarly journals Comparison of transient states in step-down power converter (BUCK) in continuous and discontinuous conduction mode

2014 ◽  
Vol 62 (4) ◽  
pp. 773-778
Author(s):  
W. Janke ◽  
M. Walczak
Keyword(s):  
Separation Of Variables ◽  
Power Converter ◽  
Order Type ◽  
First Order ◽  
Transient States ◽  
Discontinuous Conduction Mode ◽  
Fast Transients ◽  
Step Down ◽  
Averaged Models ◽  
Conduction Mode

Abstract The object of this paper is a step-down (BUCK) power converter working in the continuous conduction mode (CCM) or discontinuous conduction mode (DCM). Two types of transient states in a converter have been analyzed and observed experimentally: slow transients, described by averaged models of a converter and fast transients, in the course of a single switching period. The averaged models of converter working in CCM, presented in various sources are similar, with some differences concerning only the description of parasitic effects. The averaged models for DCM depend on the adopted modeling method. Models obtained by the switch averaging approach are second-order models (containing two reactive elements in equivalent circuit representation). Models obtained by the separation of variables approach are first-order models. The experimental results given in this paper show the first-order type of transients. Another group of experiments concern fast transients in the course of a single switching period. The oscillations of inductor voltage in the part of a switching period are observed for DCM.

Averaged models of pulse-modulated DC-DC power converters. Part II. Models based on the separation of variables

2012 ◽  
Vol 61 (4) ◽  
pp. 633-654 ◽  
Author(s):  
Włodzimierz Janke
Keyword(s):  
Power Converters ◽  
Averaging Method ◽  
Separation Of Variables ◽  
Small Signal ◽  
Large Signal ◽  
Dc Power ◽  
Switch Mode ◽  
Standard Models ◽  
Averaged Models ◽  
The Ideal

Abstract The separation of variables approach to formulate the averaged models of DC-DC switch-mode power converters is presented in the paper. The proposed method is applied to basic converters such as BUCK, BOOST and BUCK-BOOST. The ideal converters or converters with parasitic resistances, working in CCM and in DCM mode are considered. The models are presented in the form of equation systems for large signal, steady-state and small-signal case. It is shown, that the models obtained by separation of variables approach differ in some situations from standard models based on switch averaging method.

Averaged models of pulse-modulated DC-DC power converters. Part I. Discussion of standard methods

2012 ◽  
Vol 61 (4) ◽  
pp. 609-631 ◽  
Author(s):  
Włodzimierz Janke
Keyword(s):  
Power Converters ◽  
Standard Methods ◽  
Practical Applications ◽  
Dc Power ◽  
Switch Mode ◽  
Model Derivation ◽  
Averaged Models ◽  
Averaged Model ◽  
Conduction Mode ◽  
The Ideal

Abstract The averaged models of switch-mode DC-DC power converters are discussed. Two methods of averaged model derivation are considered - the first, based on statespace averaging and the second, on the switch averaging approach. The simplest converters: BUCK, BOOST and BUCK-BOOST working in CCM (continuous conduction mode) or DCM are taken as examples in detailed considerations. Apart from the ideal converters, the more realistic case of converters with parasitic resistances is analyzed. The switch averaging approach is used more frequently than the other and is believed to be more convenient in practical applications. It is shown however, that in the deriving the averaged models based on the switch-averaging approach, some informalities have been made, which may be the source of errors in the case of converters with parasitic resistances, or working in DCM mode.

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