The fundamental principles, essential functions, and optional functions of a virtual synchronous machine (VSM) to make power electronic converters standardized for different applications and suitable for single-unit operation, multi-unit operation, islanded/off-grid operation, and grid-tied operation, facilitating the large-scale utilization of DER and the integration of power electronic converters into the grid, and advancing energy freedom and energy access are defined in this standard.

This recommended practice defines the fundamental principles, essential functions, and optional functions of a virtual synchronous machine (VSM). A VSM is a piece of equipment that includes a dc/ac power electronic converter (PEC) controlled to mimic and, in some cases, to surpass the dynamics and behavior of conventional synchronous machines (SM) through the inherent synchronization mechanism of SM. It does not describe or specify power semiconductor devices, hardware topologies, or micro-controllers that are used to build a VSM. This standard is about equipment operation rather than grid requirements, which are covered by IEEE Std 1547-2008 [B2] and IEEE Std 2800-2022 [B3]. Equipment complying with this standard are able to work individually, to form a grid, and to interact with the grid. This standard focuses on VSM only, rather than generic criteria that apply irrespective of the specific control implementation. The boundary of this standard is at the equipment terminals, which includes the phase terminals, plus a neutral terminal, plus a ground terminal on the ac side and the dc-bus terminals on the dc side, while IEEE Std 1547- 2008 [B2] and IEEE Std 2800-2022 [B3] consider the point of connection (PoC) or point of common coupling (PCC) as the boundary. As a result, anything outside of the equipment terminals, such as the energy source, the load, and/or the grid, are not covered in this standard.