Universal Passive Synchronization Method for Grid-Forming Inverters Without Mode Transition

Heather Chang, Nathan Baeckeland, Abhishek Banerjee, Gab-Su Seo

Research output: Contribution to conferencePaper

3 Scopus Citations


Power systems are transforming with increasing levels of inverter-based resources (IBRs). This transformation requires critical roles of grid-forming (GFM) inverters replacing synchronous generators for bulk power system stabilization and ancillary services, also allowing flexible power system operation, such as microgrid that is operated by multiple GFM IBRs to achieve system resilience against contingencies. To realize the resilient power systems allowing flexible in-and-out operation of GFM IBRs potentially programmed with different primary controls, a synchronization method universally applicable, i.e., independent of control types, would be beneficial to ease the integration process, but it has not been actively studied. To fill the gap, this paper proposes a universal synchronization method that achieves a passive synchronization to enable a smooth transition in a grid with off-nominal system parameters, i.e., voltage and frequency. The logic proposed requires no modification on the primary control, thus applicable to any type of GFMs with a voltage reference input. To validate the concept, a simulation of an IEEE 13-bus benchmark system modified with 3 GFM inverters is presented. It simulates an inverter-driven black start scenario in which GFM inverters autonomously turn on and connect to the grid under heavy loading, using the synchronization logic. The case study demonstrates that GFM inverters can tune their voltage reference to smoothly synchronize without severe transients, and contribute to a seamless black start of the grid under unbalanced load conditions. Two GFM methods - Droop and dispatchable virtual oscillator control - are used for the demo to validate feasibility and interoperability of the passive synchronization.
Original languageAmerican English
Number of pages7
StatePublished - 2023
Event2023 11th International Conference on Power Electronics and ECCE Asia (ICPE 2023 - ECCE Asia) - Jeju Island, Korea
Duration: 22 May 202325 May 2023


Conference2023 11th International Conference on Power Electronics and ECCE Asia (ICPE 2023 - ECCE Asia)
CityJeju Island, Korea

Bibliographical note

See NREL/CP-5D00-86972 for preprint

NREL Publication Number

  • NREL/CP-5D00-87692


  • black start
  • grid-forming inverter
  • inverter synchronization
  • inverter-based resources
  • passive synchronization


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