Extended Filippov's Method for Stability Analysis of Digitally Controlled DC–DC Converters

The same as Poincaré map, Filippov's method is also an effective method to analyze the stability of power converters. Moreover, it is easier to implement. However, the existing Filippov's method is designed only for analog-controlled converters. To expand its application fields, an extended Filippov's method is presented for digitally controlled dc–dc converters. The closed-form expression of the monodromy matrix of a general digitally controlled dc–dc converter is established. Based on the obtained monodromy matrix, the stability of the digitally controlled dc–dc converter can be assessed easily. Finally, the correctness of the proposed method is experimentally verified by two classic dc–dc converters.