DC microgrids have the advantage of increased reliability and controllability, as well as the absence of synchronization and the stability problems that come with synchronization. Bipolar DC microgrids have significant advantages over traditional two-wire microgrid systems in terms of efficiency, safety and transmission capacity, but midpoint potential asymmetry has always been a problem in the operation of bipolar DC microgrids. The three-level rectifier is used to serve the bipolar DC microgrid. The modeling and simulation is carried out by MATLAB/Simulink, based on the dual closed-loop voltage and current control, the output proportional adjustment factor is adjusted to the differential voltage across the capacitors, and then the proportional adjustment factor is injected into the SVPWM algorithm to adjust the operating time of the small vector, which makes the midpoint potential symmetrical and also enables the smooth operation of the bipolar DC microgrid.