An Energy Hub Based on Virtual-Machine Control

The energy hub is one of the key technologies under the umbrella concept of energy internet. The energy hub topology and its control scheme will closely affect the flexible operation of future grids in terms of conversion and renewable integration. An AC/DC hybrid electric energy hub was proposed with a modular structure and isolation on the line-frequency AC side. Using the hub,the low voltage AC and DC distribution networks,renewable energy sources,energy storage devices and loads can be easily integrated into the utility system. A virtual-machine-based control strategy was presented for the energy hub to emulate the machine inertia and damping,improving its stability. Based on the study using established models and a virtual-machine-based control scheme,a small-signal model and power sharing scheme of the energy hub were proposed. Finally,focusing on a typical energy hub system,the validity and effectiveness of the proposed topology and control strategy are verified by using PSCAD/EMTDC. The proposed model and analysis approach can be useful in future energy internet and energy hub development.