Optimized Virtual DC Machine Control for Voltage Inertia and Damping Support in DC Microgrid

Voltage inertia and damping characteristics are the key to improve the voltage dynamic stability of DC microgrid. This paper simulates the operation performance of DC motor to improve the voltage inertia and damping characteristics of bi-directional DC-DC converter (B-DC). A dynamic model suitable for DC motor is established. In order to improve the sensitivity of voltage control, a variable voltage drop control loop is designed and implemented as a part of vdmc. Based on Middlebrook stability criterion, the influence of additional loop on DC microgrid stability is estimated. Finally, experimental tests on a hardware-in-the-loop platform of a DC microgrid are carried out to validate the proposed control strategy. The results demonstrate that both inertia support function and voltage damping are improved using the proposed VDMC. Consequently, the dynamic stability of the DC microgrid is significantly improved.