[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.