Analysis of subharmonic oscillation of fixed-frequency current-programming switch mode power converters

Author

Ki, Wing-Hung

Author_Institution

Dept. of Electr. & Electron. Eng., Hong Kong Univ. of Sci. & Technol., Hong Kong

Volume

45

Issue

1

fYear

1998

fDate

1/1/1998 12:00:00 AM

Firstpage

104

Lastpage

108

Abstract

Subharmonic oscillation of a generic fixed-frequency current-programming switch mode power converter (SMPC) operating in the continuous-conduction mode (CCM) is analyzed. The conditions for oscillation are derived by the geometric approach as well as by analyzing the converter in the discrete time domain and are shown to be equivalent. In obtaining the state-space averaged differential equation, the forward Euler approximation is invoked. This z→s transformation maps a z-domain pole outside the unit circle that causes the oscillation to a s-domain pole in the left-half plane (LHP), which has previously been overlooked. The analysis is then applied to a current-programming buck converter, which suggests the two correct control equations for both converters employing either trailing- or leading-edge modulation

Keywords

circuit oscillations; nonlinear network analysis; poles and zeros; power convertors; switching circuits; time-domain analysis; buck converter; continuous-conduction mode; control equations; current-programming power converters; discrete time domain; fixed-frequency convertors; forward Euler approximation; leading-edge modulation; s-domain pole; state-space averaged differential equation; subharmonic oscillation; switch mode power converters; trailing-edge modulation; z-domain pole; Delay; Equations; Filtering theory; Filters; Network address translation; Signal processing; Switches; Switching converters; Transfer functions; Transient response;

fLanguage

English

Journal_Title

Circuits and Systems I: Fundamental Theory and Applications, IEEE Transactions on

Publisher

ieee

ISSN

1057-7122

Type

jour

DOI

10.1109/81.660771

Filename

660771