Title :
A comparison and an improvement of two continuous-time models for current-mode control
Author :
Johansson, Bengt
Author_Institution :
Dept. of Technol., Univ. of Kalmar, Sweden
Abstract :
Current-mode control can be used to control switched DC-DC power converters. This paper compares two continuous-time models for current-mode control that are made to be accurate up to half the switching frequency. The two models are the ones presented by Ridley and Tan. The closed loop frequency responses predicted by these two models are compared with results obtained from simulations of a buck converter in continuous conduction mode. The control-to-output transfer functions and the output impedances predicted by the two models agree very well with the simulation results. This is however not the case for the audio susceptibility. A new expression for the audio susceptibility is presented in this paper and is used to improve the two models.
Keywords :
DC-DC power convertors; closed loop systems; continuous time systems; control system analysis; electric current control; frequency response; switching convertors; transfer functions; audio susceptibility; closed loop frequency responses; continuous conduction; continuous-time models; control simulation; control-to-output transfer functions; current-mode control; output impedances; switched DC-DC power converters; switching frequency; Buck converters; DC-DC power converters; Frequency conversion; Frequency locked loops; Impedance; Inductors; Predictive models; Switching converters; Switching frequency; Transfer functions;
Conference_Titel :
Telecommunications Energy Conference, 2002. INTELEC. 24th Annual International
Print_ISBN :
0-7803-7512-2
DOI :
10.1109/INTLEC.2002.1048711
