Control of Aggregated Virtual Synchronous Generators for PV Plants Considering Communication Delays

In this paper, a new method for the delay compensation when using an aggregation of virtual synchronous generators is proposed. Lack of inertia in power converters can potentially provoke stability issues that can be mitigated by the use of virtual inertia techniques. Among those, the Virtual Synchronous Generator (VSG) concept has received strong impulse in the last years. This paper is focused on the idea of using the distributed VSG concept in a renewable power plant, in which a single Synchronous Central Angle Controller (SCAC) is used for the power control exchange at the Point of Connection (PoC), while distribution control units are employed for the local inverter control. This idea, already discussed in the literature, is in here extended to consider the implementation on industrial string-level commercial power converters, recalling the importance of accessible measurements and communication delays. In order to validate the proposal, firstly communication delays are measured and modelled. Following, simulations with different SCAC operating modes are conducted, and finally experimental results validation of different operation modes with commercial converters are presented.