Review of general modeling approaches of power converters

The modeling approaches of power converters occupy an important position in power electronic systems and have made considerable progress over the past years. Continuous modeling approaches and linearization techniques are reviewed, including the state-space average model, generalized average model, averaged small-signal model, and describing function method. A Buck converter with PWM modulation and voltage-mode control is taken as an example to compare the advantages and disadvantages of different methods through simulation analysis. Moreover, the corresponding equivalent circuit with an intuitive physical meaning of state-space average model, generalized average model, and averaged small-signal model is given. The results point out that the generalized average model can improve the modeling accuracy based on the state-space average model. In the linearization techniques, the averaged small-signal model reflects accuracy at low frequencies, but introduces phase lag in the high-frequency region. The describing function method is derived from harmonic linearization, which takes into account the sideband effect and improves the modeling accuracy at high frequencies.