BEGIN:VCALENDAR VERSION:2.0 PRODID:IEEE vTools.Events//EN CALSCALE:GREGORIAN BEGIN:VTIMEZONE TZID:America/Los_Angeles BEGIN:DAYLIGHT DTSTART:20260308T030000 TZOFFSETFROM:-0800 TZOFFSETTO:-0700 RRULE:FREQ=YEARLY;BYDAY=2SU;BYMONTH=3 TZNAME:PDT END:DAYLIGHT BEGIN:STANDARD DTSTART:20251102T010000 TZOFFSETFROM:-0700 TZOFFSETTO:-0800 RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=11 TZNAME:PST END:STANDARD END:VTIMEZONE BEGIN:VEVENT DTSTAMP:20251118T201939Z UID:8FEC5E62-F1F0-471E-B542-0F10EED5809A DTSTART;TZID=America/Los_Angeles:20251118T093000 DTEND;TZID=America/Los_Angeles:20251118T110000 DESCRIPTION:Grid-forming (GFM) inverter research has accelerated as inverte r-based resources (IBRs) become dominant. Unlike grid-following (GFL) unit s\, GFM inverters establish their own voltage and frequency references\, e nabling operation at high IBR penetration. System operators\, research ins titutions\, and industry are therefore calling for GFM capabilities in gri d-connected converters. Yet the transition from synchronous-generator (SG) dominated systems to GFM-rich grids remains challenging: open questions p ersist regarding desired GFM behavior during disturbances (balanced/unbala nced faults\, frequency or phase jumps\, and overloading)\, the system-lev el impacts on stability and protection\, and the resulting control design implications. This talk addresses two of these questions.\n\nPart I examin es the consequences of strictly limited overcurrent capability in power-el ectronic converters. To protect hardware\, GFM inverters must implement fa st current limiting\; once engaged\, however\, the inverter departs from i deal voltage-source behavior and can destabilize the system. The presentat ion will review widely used current-limiting schemes\, introduce a frequen cy-stabilization strategy tailored for large disturbances\, and present a recently proposed equivalent-impedance framework that quantifies the resul ting stability margins. A complementary small-signal model then explains v oltage-oscillation mechanisms arising from limiter-stabilizer interactions . The analysis reveals key design trade-offs and leads to a practical cont rol-tuning workflow.\n\nPart II explores using Stuart–Landau nonlinear o scillators as the synchronizing core of GFM control to enhance reliability \, disturbance rejection\, and dynamic performance under weak\, non-ideal\ , or unbalanced conditions. A cascaded architecture is adopted: an outer G FM layer sets voltage/frequency references\, while a nonlinear\, passivity -based inner loop enforces them\, providing global asymptotic stability\, stronger damping\, and faster transients than conventional linear approach es. To capture magnetic saturation in interfacing elements\, a gray-box mo del combines physics-based relations with measured characteristics\; a hig h-gain observer estimates nonlinear inductance online\, enabling adaptive gain scheduling across operating points. MATLAB/Simulink and PLECS studies demonstrate robust regulation\, strong disturbance rejection\, and resili ence to load changes\, parameter uncertainty\, and weak-grid scenarios.\n\ nSpeaker(s): Bowen Yang\, Vikram Roy Chowdhury\n\nVirtual: https://events. vtools.ieee.org/m/514490 LOCATION:Virtual: https://events.vtools.ieee.org/m/514490 ORGANIZER:justin.zhang@ubc.ca SEQUENCE:18 SUMMARY:Grid-Forming Inverters Under Disturbance: Current Limiting and Nonl inear Synchronization URL;VALUE=URI:https://events.vtools.ieee.org/m/514490 X-ALT-DESC:Description: <br /><p class="MsoNormal" style="text-align: justi fy\;">Grid-forming (GFM) inverter research has accelerated as inverter-bas ed resources (IBRs) become dominant. Unlike grid-following (GFL) units\, G FM inverters establish their own voltage and frequency references\, enabli ng operation at high IBR penetration. System operators\, research institut ions\, and industry are therefore calling for GFM capabilities in grid-con nected converters. Yet the transition from synchronous-generator (SG) domi nated systems to GFM-rich grids remains challenging: open questions persis t regarding desired GFM behavior during disturbances (balanced/unbalanced faults\, frequency or phase jumps\, and overloading)\, the system-level im pacts on stability and protection\, and the resulting control design impli cations. This talk addresses two of these questions.</p>\n<p class="MsoNor mal" style="text-align: justify\;">Part I examines the consequences of str ictly limited overcurrent capability in power-electronic converters. To pr otect hardware\, GFM inverters must implement fast current limiting\; once engaged\, however\, the inverter departs from ideal voltage-source behavi or and can destabilize the system. The presentation will review widely use d current-limiting schemes\, introduce a frequency-stabilization strategy tailored for large disturbances\, and present a recently proposed equivale nt-impedance framework that quantifies the resulting stability margins. A complementary small-signal model then explains voltage-oscillation mechani sms arising from limiter-stabilizer interactions. The analysis reveals key design trade-offs and leads to a practical control-tuning workflow.</p>\n <p class="MsoNormal" style="text-align: justify\;">Part II explores using Stuart&ndash\;Landau nonlinear oscillators as the synchronizing core of GF M control to enhance reliability\, disturbance rejection\, and dynamic per formance under weak\, non-ideal\, or unbalanced conditions. A cascaded arc hitecture is adopted: an outer GFM layer sets voltage/frequency references \, while a nonlinear\, passivity-based inner loop enforces them\, providin g global asymptotic stability\, stronger damping\, and faster transients t han conventional linear approaches. To capture magnetic saturation in inte rfacing elements\, a gray-box model combines physics-based relations with measured characteristics\; a high-gain observer estimates nonlinear induct ance online\, enabling adaptive gain scheduling across operating points. M ATLAB/Simulink and PLECS studies demonstrate robust regulation\, strong di sturbance rejection\, and resilience to load changes\, parameter uncertain ty\, and weak-grid scenarios.</p> END:VEVENT END:VCALENDAR