Abstract: Aiming at the demand of intelligent coal mine and exit problem of underground coal mine power

network，an energy storage hybrid distribution transformer based on modular multilevel converter（MMC-HDT）

was proposed. Firstly，the proposed energy storage MMC-HDT was modeled and four operation modes were given

considering grid fault and state of charge（SOC）. Secondly，the passivity-based controller was designed according

to the port controlled Hamiltonian with dispersion（PCHD）model on the AC side of MMC-HDT. Finally，the

switching control strategy of four operation modes was designed. The experimental results show that the proposed

control strategy in energy storage MMC-HDT can further reduce the steady-state total harmonic distortion（THD）

rate of feeder current and effectively limit the unrestricted sudden increase of feeder current in case of voltage fault.

In any grid voltage fault state，the load voltage can be maintained at the rated value，the function of uninterrupted

power supply can be realized，and the reliability of the distribution system can be improved.

      Key words: hybrid distribution transformer（HDT）；port controlled Hamiltonian with dispersion（PCHD）；

passivity-based control；modular multilevel converter（MMC）