Xiaoyang Wang and Xin Chen's unified framework enables seamless inverter mode switching

A new research paper from Xiaoyang Wang and Xin Chen, published on arXiv, presents a unified control framework that bridges the gap between grid-forming (GFM) and grid-following (GFL) inverters. Traditionally, these inverters rely on discrete controller switching to change operating modes, which can cause instability and transient issues. The proposed solution merges dispatchable virtual oscillator control with reference-following synchronization, allowing a single controller to handle multiple behaviors. This eliminates abrupt switching and provides a physically interpretable approach to adapting inverter dynamics.

The unified framework supports five distinct operating modes within a single structure: voltage- and frequency-following (PQ), voltage-forming and frequency-following (PV), voltage-following and frequency-forming (Qf), voltage- and frequency-forming (Vf), and a hybrid mode mixing GFM and GFL traits. By tuning a small set of continuous control parameters, the inverter can smoothly pre-synchronize to the grid and transition between modes—critical for renewable energy systems that face fluctuating grid conditions. The authors also analyze small-signal stability and input-output frequency-domain characteristics. Extensive electromagnetic transient (EMT) simulations and hardware-in-the-loop (HIL) experiments confirm the method's effectiveness and robustness, making it a promising step toward more flexible and resilient power electronics control.