In the design and application of the high power converter products, the root mean square (RMS) ripple current of the support capacitor of the converter module is too large, resulting from the mismatch of stray inductance of the busbar, and the capacitor works in excess state for a long time, resulting in damage. In view of the above problems, the corresponding mathematical model according to the different busbar structures of the converter module is established, and the root cause of the large support capacitor current is analyzed. The stray inductors of different busbar structures are measured and extracted by experiments to guide the design of subsequent busbar. According to the theoretical analysis, it is proposed to reduce the ripple current of bus support capacitor by optimizing the bus bar design and improving the control algorithm. Finally, based on a converter platform, the capacitive current ripple under different experimental conditions is measured, and the experimental data are compared and analyzed to verify the effectiveness of the proposed improved measures.