UBC Theses and Dissertations
Parametric average value modeling of PWM DC-DC converters Davoudi, Ali
State-space average value modeling of hard switching PWM converters in continuous and discontinuous conduction modes has received significant attention in the literature and various models have been derived. In this thesis, a" new approach for generating the average value model is set forth in which the parasitic effects of circuit elements are readily included. In the proposed methodology, the so-called duty ratio constraint and correction term are extracted numerically using the detailed simulation and expressed as nonlinear functions of the duty cycle and the average value of fast state variable. The proposed methodology is also generalized by representing these numerical functions in terms of duty cycle and the switching-cell dynamic-impedance. An automated small-signal characterization method using a general purpose simulator is also proposed. The resulting parametric average value model is compared with the hardware prototype, the detailed simulation and the analytically averaged model. The proposed model is shown to be very accurate in predicting large-signal time-domain transients as well as small-signal frequency-domain characteristics.
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