Experimental evaluation of virtual synchronous generators with high regulation performance to enhance AC–DC grid interconnections

Abstract

In the recent years there has been a significant increase in the interest surrounding the interconnection of AC and DC networks due to its potential to improve the power systems reliability. Despite the potential advantages, however, the AC and DC grid coexistence can pose challenges if not appropriately managed. In this scenario, this paper presents an enhanced control scheme enabling the use of Virtual Synchronous Generators (VSGs) as elements of interconnection between AC and DC networks. The proposed solution enables VSG operation with both fast dynamics for DC voltage regulation and slow dynamics for AC inertia emulation. This approach accommodates the contrasting requirements arising from the distinct mechanisms of DC voltage regulation and AC frequency regulation. Simulation and experimental results obtained with a 8 kVA three-phase converter prototype are provided to validate the effectiveness of the proposed technique and prove its better performances with respect to the solutions currently presented in literature.

Keywords

• Static synchronous generators
• Multi-terminal DC systems
• Voltage regulation
• Inertia emulation
• DC–AC interconnections