Abstract
This paper investigates the effectiveness of virtual synchronous machine based on three-phase voltage source converter. The virtual machine can effectively slow down frequency dynamics in micro-grid, which is achieved by emulating the damping and inertia of synchronous machine. Besides, the theoretical analysis indicates the virtual synchronous machine is closely related to the conventional droop control, and their performances are compared and discussed. Nevertheless, both controls may lead to micro-grid frequency deviated from the nominal value, so this study also takes the frequency restoration into consideration. In the end, laboratory test results are supported to validate their benefits.