Grid-Forming Inverter

A grid-forming inverter is a power electronic device that sets its own voltage and frequency the way a spinning generator does, rather than simply synchronizing to a voltage the wider grid already provides. Conventional inverters connecting solar panels, wind turbines and batteries to the grid are grid-following: they measure the existing grid voltage and inject current in step with it, which means they shut down during grid disturbances and cannot themselves stabilize a grid or supply the physical inertia that spinning generators once provided for free. Grid-forming inverters use active electronic control loops, sometimes described as a virtual oscillator, to hold up voltage and ride through disturbances, at the cost of needing oversized power electronics and paired energy storage. As solar and wind generation displace conventional power plants and their rotating machinery, grid-forming inverters, often paired with batteries or synchronous condensers, are increasingly seen as necessary to keep a renewables-heavy grid stable.