Periodic variation in the effect of switching frequency on the harmonics of power electronic converters

Abstract

Switching frequency is an important factor in the performance control of power electronic converters. It can help optimize switching losses, switching ripples and electromagnetic interference, especially for newly developed high-switching-frequency silicon carbide converters. Periodic variation in the switching-frequency methods has been developed for this purpose, especially the model-predictive variable switching-frequency pulse width modulation (VSFPWM) method. The effect of periodic switching-frequency variation on the harmonics of a converter using double Fourier analysis and simulations are investigated. This work verifies that the switching harmonics can be reduced by periodic variation in the switching frequency, and the low-frequency (baseband) harmonics only incur a slight change. The analysis provides a theoretical foundation for the application of VSFPWM in power electronic converters.