In order to improve the dynamic performance of bidirectional grid-connected converters and solve the problem that the DC bus voltage is susceptible to power fluctuations in DC microgrids

a virtual inertia control strategy based on passivity-based control is proposed in this paper

that is

the inner loop is passivity-based control

which can achieve good tracking of the desired value of inductor current

and the outer loop is virtual inertia control

which can enhance the inertia of the DC microgrid and improve the DC bus voltage stability. By establishing the small signal model of the system

the performance and stability of the bidirectional grid-connected converter are analyzed. Simulation and experimental results show that

compared with the traditional virtual inertia control strategy based on PI control

when the control strategy proposed in this paper is adopted

the voltage fluctuation amplitude is reduced by about 5 V when the load changes. Thus the dynamic performance of bidirectional grid-connected converter is better

and the inertia of the DC microgrid is also effectively improved. This control strategy can also be extended to the control of other types of converters in DC microgrids.