Accurate Modeling and Stability Analysis for Chaotic PWM Boost Converters Based on Describing Function Method

Chaotic pulse width modulation (PWM) is introduced to Boost converters to suppress its electromagnetic interference. However, the conventional stability criterion with linear modeling method is not accurate and unpractical for chaotic PWM Boost converters because of the chaotic dynamic characteristics and the switching frequency variation. In this paper, the describing function method is applied to model the switching process under chaotic PWM in Boost converters with considering the chaotic switching frequency. Further, based on the derived describing function, the accurate stability analysis criterion of chaotic PWM Boost converters can be obtained, the stable region is a little smaller compared with the conventional PWM with fixed switching frequency. Finally, the simulation and experiment results demonstrate the accuracy and effectiveness of the proposed describing function method based on a Boost converter. Therefore, this paper provides a stability analysis method for Boost converters under chaotic PWM.