Enhanced DC-link Voltage Control in a Virtual Synchronous Generator-Based Building-to-Building Grid Considering Islanded Mode Operation

The paper presents a droop-based power sharing with a voltage restore dc-link voltage control for a proper power exchange in a virtual synchronous generator (VSG) based building-to-building grid. Under the VSG paradigm, usually proportional-integral (PI) control is used to regulate the dc-link voltage using the energy storage-side, typically, or the grid-side converter. However, this affects the system performance when the load or generation changes. In our proposal, a dc-link droop-based voltage control is implemented using the battery and the interlinking grid converter with an additional voltage restoration controller. The interlinking converter is controlled using a modified VSG control, with a power reference coming from the dc-link voltage controller. The proposed system allows smooth transition from/to islanded to/from grid-connected operation with a pre-synchronization and islanding detection method.