Harmonic current pollutions caused by nonlinear loads is a universal phenomenon in distribution systems. The medium voltage direct current distribution system based on a modular multilevel converter（MMC-MVDC） can effectively suppress the harmonic current on the network side by optimizing the appropriate control strategy. In this paper

based on the traditional inner loop PI controller

the harmonic current tracking without static difference is realized based on the proportional resonance controller

and a networkside current closed-loop control strategy of the MMC-MVDC distribution system is proposed

which dispenses with harmonic separation algorithm and employs a dual closed-loop control structure with independent fundamental and harmonic current and the control link delay compensated. It can realize multi-terminal system interconnection

power flow optimization and harmonic control at the same time. Based on MATLAB

the amplitude-frequency characteristics of the power control loop and harmonic suppression loop are analyzed

and the excellent stability of the system is verified. The scheme is applied to the three-terminal MMC-MVDC distribution system

and the RTDS test results verify the correctness and effectiveness of the control strategy.