[Objective] Silicon carbide (SiC) devices

characterized by low switching losses and high voltage endurance

demonstrate significant advantages in modular multilevel converter (MMC) for medium-voltage applications. However

submodules based on SiC devices generate high du/dt and di/dt during switching transients

leading to severe electromagnetic interference that compromises system safety. [Methods] To address this issue

this study analyzed the stray capacitance distribution characteristics of submodules based on the MMC topology. By performing an equivalent transformation of stray capacitance

an equivalent circuit model for common-mode interference was established. On this basis

a novel common-mode current suppression strategy was proposed

employing carrier phase-shifted pulse width modulation with complementary submodules triggering pulses in the upper and lower bridge arms. By adjusting the carrier phase of the complementary submodules

common-mode current suppression was achieved. [Results] Simulation results showed that the proposed method effectively maintained submodules capacitor voltage balance and ensured high-quality AC-side output waveforms

both of which were critical performance factors for MMC. Compared to conventional methods

the proposed strategy reduced the peak common-mode current by 43%

demonstrating better suppression capability and validating its effectiveness. [Conclusion] The proposed method effectively suppresses common-mode interference current

enhancing the overall integrity and reliability of SiC MMC. These findings provide valuable insights into the advancement of power electronics technology in medium-voltage applications.