A Flexible Virtual Capacitance Control Strategy for DC Micro-Grid

Abstract

Compared with AC grid, DC micro-grid has little inertia. Therefore, when the system suffers from transient disturbance, it is easy to cause DC voltage mutation and even system instability. In the AC system, the inertia can be developed by applying virtual synchronous generator(VSG) control to the converter. A flexible virtual capacitance(FVC) control strategy for DC micro-grid is proposed by analogizing the correspondence of variables between AC and DC systems. Potential “inertia” in DC micro-grid can be developed with the proposed control strategy, and the system stability can be improved by restraining the mutation of DC voltage.