HAIT Journal of Science and Engineering B Volume 2, Issues 3-4, pp. 452-475 © 2005 Holon Academic Institute of Technology |
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Unified small-signal model for PCM control in CCM: unterminated modeling approachTeuvo Suntio* and Mikko Hankaniemi |
Institute of Power Electronics, Tampere University of Technology P.O. Box 692, FI-33101 Tampere, Finland *Corresponding author: teuvo.suntio@tut.fi Received 1 March 2005, accepted 10 August 2005 |
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The small-signal modeling of peak-current-mode (PCM) controlled switched-mode converters has attracted the researchers and caused lively discussions since the invention of the control mode. The application of the PCM control makes the converter to resemble a current source at open loop rather than a voltage source, what it actually is, when the feedback loop is connected. The current-source nature has caused problems to study the converter dynamics and the anomalies it has, such as the limited duty ratio. As a consequence, generally accepted small-signal models are not available but only a variety of models serving the interests of different schools. In this paper, we will show definitively that the models including infinite duty-ratio gain form the basis for the accurate small-signal modeling as well as explain fully the phenomena characteristic to PCM control. Keywords: Peak-current-mode control, switched-mode converter, mode limit, CCM |
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