Electric spring (ES) is mainly used to stabilize the voltage of the critical load (CL) under the condition of power fluctuation in the grid. Through the bidirectional flow of energy, the DC side energy storage system of ES can flexibly compensate active and reactive power in the distribution network. However, the DC side has a large volume and lacks systematic energy monitoring and management due to the high voltage level. In this paper, an ES topology based on modular multilevel converters (MMC) is proposed to simplify the storage side structure, and a digital energy management strategy based on the proposed topology is proposed. The effectiveness of the proposed topology is verified by the simulation results.

electric spring;modular multilevel converter;sinusoidal pulse width modulation;reactive power compensation