A Unified Grid-Forming and Grid-Following Primary Control Design With Optimized Enforcement of Grid Operational Constraints

A novel, unified control design is proposed for software-defined inverters (SDIs) to operate in either grid-forming (GFM) or grid-following (GFL) mode AC grids/microgrids and switch between the two modes seamlessly. The GFM GFL controls are systematically developed analytically synthesized based on dynamic state space models of inverter, its output filters, terminal voltage current at grid/microgrid. have, a) a nonlinear nominal tracking as seed design, b) constraint-enforcing control. tracks frequency, voltage-magnitude, angle, while frequency well real reactive power references. Tracking vector ensured under recursive Lyapunov paradigm, naturally resulting consistent laws. This paradigm allows implementation that ensures voltage, power, injections dynamically satisfy their operational constraints presence load variations intermittent renewable sources. Stability convergence controls, constraint enforcement concluded analytically, effectiveness demonstrated through simulations.