A Fast Self-synchronizing Synchronverter Design with Easily Tuneable Parameters

Abstract

This paper proposes a fast self-synchronizing synchronverter controller design, which synchronizes the synchronverter inner voltage to the grid-side voltage without needing to measure its phase angle, prior to physical connection to the grid. The proposed design centres on the addition of a virtual resistance branch (along with a suitable coordinate transformation), which provides the controller with virtual active- and reactive-power output feedback signals during self synchronization, even though the actual outputs are zero before grid connection. The virtual resistance branch enables fast self synchronization by avoiding inductance dynamics in prevailing methods that use a virtual impedance branch. At the same time, the parameter tuning process is simplified as fewer parameters require tuning. Moreover, the effects of these parameters on synchronization dynamics are well defined. Time-domain simulations are provided to validate that the proposed controller design self synchronizes quickly and that its parameters are easily tuneable.