Abstract
This paper investigates the conventional droop control and the recently-developed droop control, like virtual synchronous machine (VSM) based control and Q -V control. The VSM based control can effectively smooth frequency dynamics by emulating the damping and the inertia of the synchronous machine, and Q - V droop control can enhance the more ideal results in the reactive power sharing among converters. Both controls bring their frequency and V to the initial values depending on the restoration mechanism. Such a mechanism is achieved by deviating their power reference, and it may lead to severe nonideal power-sharing when the converters asynchronously connect with the system. To improve this problem, this study presents a resetting mechanism realized through a central console. In the end, the laboratory test results are supported to validate their benefits.