Abstract: A voltage stability control strategy for DC microgrid based on muti-group energy storage unit

dynamatic regulation was proposed. Due to the volatility of the new energy，and in order to improve the power

supply reliability of the energy storage system，the multi-group energy storage equipped with a certain control

system was chosen to control the bus voltage stability. In order to avoid over-charge or deep-discharge of storage

units and reduce dependency on communication，an adaptive droop controller was designed to dynamically allocate load power among storage units considering the state of charge（SOC）of storage units，the maximum power and DC bus voltage. Meanwhile，the voltage feed forward control was designed in the power loop of droop control to reduce voltage fluctuation. Besides，the voltage stability control strategy may automatically switch converters to different working states，which ensures that there are convertors in all working conditions to control DC voltage stability and system power load balance. Finally，the simulation model of DC microgrid was built in Matlab/Simulink，and the simulation results indicate the proposed method may improve the ESS reliability and voltage quality for DC/AC load.

      Key words: DC microgrid；droop control；secondary control；voltage quality