Dynamic Coordination Control of Voltage for Multiple Energy Storage Converters in DC Microgrid

With the integration of a large number of power electronic devices, the DC microgrid exhibits low inertia characteristics. When disturbed, the bus voltage will undergo sudden changes, which can seriously affect the dynamic stability of the DC microgrid voltage. A DC microgrid voltage dynamic control strategy based on coordinated control of main energy storage and auxiliary energy storage is proposed for this purpose. Firstly, based on the control of analog virtual synchronous generators (AVSG) under the AC DC/AC converter, the AVSG control is established in the main energy storage DC/DC converter, and the small signal equation of the main energy storage DC/DC converter is derived. The characteristic root locus and unit Step response of the main energy storage DC/DC converter are analyzed, and the influence of the virtual inertia value on the system stability, inertia and dynamic response is obtained. Furthermore, based on the variation of bus voltage under disturbance, an adaptive control method for the virtual inertia of the main energy storage AVSG is proposed. Secondly, in response to the limited improvement of the voltage dynamic characteristics of the DC microgrid by the main energy storage AVSG control, based on the fixed power control of the auxiliary energy storage, an additional adaptive power compensation control method is proposed for the auxiliary energy storage DC/DC converter, which can quickly and adaptively reverse compensate for intermittent power sources or sudden power changes in the DC microgrid, effectively improving the voltage dynamic characteristics of the DC microgrid under large power disturbances. Finally, the effectiveness of the proposed control strategy was verified through Matlab/Simulink simulation analysis.