Virtual DC Motor Control Based on Virtual Capacitor for DC Microgrid

With the access of high-density distributed power supply, the inertia level of DC micro-grid continues to decline, especially under the condition of independent power supply of new energy, its inertia is far lower than the minimum inertia demand. In order to effectively improve the system inertia and enhance the dynamic stability of the power grid, a new virtual DC motor control based on virtual capacitance is proposed for the energy storage port converter. Firstly, according to the definition of inertia of DC microgrid, the main sources of inertia of DC microgrid are defined. Secondly, according to the small-signal model of the virtual capacitor, a first-order additional inertial loop is constructed, and the virtual DC motor control method based on the additional inertial loop is obtained, which realizes the improvement of the virtual DC motor control and further enhances the inertial support capability of the system. Then, the small-signal model of the new virtual DC motor control is established to explore the influence of virtual angular velocity on system stability, and the advantages of voltage dynamic performance and stability under this control method are analyzed. Finally, the correctness and effectiveness of the proposed control strategy are verified by simulation analysis.