Continuous Multi-Scroll Chaotic PWM and its Chaotic Signal Selection Method for EMI Suppression of Power Converters

Chaotic pulse width modulation (PWM) technique has been applied to suppress electromagnetic interference (EMI) in power converters. However, traditional discrete chaotic PWM has the shortcoming that the spreading spectrum distribution is triangular in shape and the practical spreading frequency bandwidth is much larger than the designed, which will further result in the limited EMI suppression. In this paper, a continuous chaotic PWM method based on the continuous multi-scroll chaotic attractors is put forward to suppress EMI more effectively, getting better spread spectrum distribution at switching frequency and its multiples for power converters. Moreover, to guide the selection of chaotic signals in real applications, the influence mechanism of multi-scroll chaotic signals on EMI spectrum distribution is firstly analyzed in this paper so as to provide a practical chaotic signal selection method. Finally, the experiments are presented followed by the simulations on a boost converter to verify the effectiveness of the proposed continuous multi-scroll chaotic PWM method and the correctness of the given chaotic signal selection method. This paper provides design guidance for the chaotic PWM in engineering applications.