Adaptive switching frequency PWM method of SiC inverters for EMI mitigation

Electromagnetic interference (EMI) noise resulting from the high-frequency harmonics in voltage source inverters (VSIs) poses a significant challenge in power electronics applications, particularly those involving silicon carbide (SiC) devices. The widely employed constant switching frequency pulse width modulation (CSFPWM) method is prone to generating high-frequency harmonics that contribute to EMI. This paper proposes an adaptive switching frequency pulse width modulation (ASFPWM) method that accounts for the nonlinear dead-time effect of inverters to mitigate EMI noise. Utilizing the Second-Order Generalized Integral (SOGI), the sum of the three-phase current harmonics is extracted. An adaptive law is developed allowing the switching frequency to adjust adaptively within a specified range based on the sum of the harmonic amplitudes. Simulation and experimental results demonstrate that the proposed ASFPWM method can effectively reduce conducted EMI when compared with the CSFPWM method.