Modular multilevel converter (MMC) is widely explored for high voltage direct current (HVdc transmission) and medium voltage direct current (MVdc) applications. The MMC is made up of submodules (SM) that are connected in series. In literature, renewable energy sources (RES) is integrated to SMs of MMC. However, integration of RES with some of the SMs result in asymmetrical power flow in arms and SM capacitor voltage ripple. This also results in increased total harmonic distortion (THD) in ac current, more arm currents, and large circulating current. For mitigating such issues, this paper proposes a battery energy storage system (BESS) integrated at the SMs of MMC. A proportional controller is developed to control the power flow in proposed system to achieve the reduction in the dc voltage ripple of SM capacitors. This further helps in total harmonic distortion (THD) reduction in grid current. Performance of the system is verified using MATLAB/Simulink platform.