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Small-Signal Analysis of Naturally-Sampled Single-Edge PWM Control Loops.
- Source :
-
IEEE Transactions on Power Electronics . Jan2018, Vol. 33 Issue 1, p51-64. 14p. - Publication Year :
- 2018
-
Abstract
- This paper presents a simple method to analyze the behavior of feedback loops that contain a naturally-sampled single-edge pulse-width modulator. A small-signal model is derived by means of simple geometric arguments. It is shown how this small-signal model can be used to analyze the stability of the continuous-time pulse-width modulated feedback loop by using standard $z$-domain techniques. The strategy relies on familiar concepts like transfer functions and small-signal gains and does not require any in-depth knowledge of nonlinear systems. A simple design process, where the continuous-time compensator is designed directly in the $z$-domain, is developed and detailed design equations are derived for a PI current regulator. It is shown how the proposed strategy can accurately predict instability that cannot be explained by means of the well-known average model of the pulse-width modulator. The theoretical analysis is confirmed by means of detailed time-domain simulations. The mechanisms that lead to instability are discussed and an equation for the critical loop gain is derived. [ABSTRACT FROM PUBLISHER]
Details
- Language :
- English
- ISSN :
- 08858993
- Volume :
- 33
- Issue :
- 1
- Database :
- Academic Search Index
- Journal :
- IEEE Transactions on Power Electronics
- Publication Type :
- Academic Journal
- Accession number :
- 125562446
- Full Text :
- https://doi.org/10.1109/TPEL.2017.2666720