Review and Applications of Virtual Synchronous Machines Technologies

Renewable energy such as solar or wind energy provides new possibilities to meet the world's energy needs. However, connecting renewable energy sources to the power grid at a large scale will cause huge stability challenges at the connection interface. Virtual synchronous machine (VSM) technologies, which emulate the transient electromechanical characteristics of traditional synchronous machines, offer a unified interface for smart grid integration. With these technologies, all the renewable energy generators as well as the flexible loads could take part in regulating the grid frequency and voltage, thus improving the power grid's stability. This paper presents the origin and development of VSM technology, and evaluates the mathematical model, control strategies and stability issues of the technology. It then summarizes VSM applications related to the grid interconnection of renewable energy, voltage sourced converter based HVDC (VSC-HVDC), motor speed regulation, and fast-charging interfaces. Finally, future research directions are assessed