Complex Variable Design for Power Control of Grid-Forming Inverter

The analysis and design of the grid-forming (GFM) power loop and decoupling control can be challenging due to the coupled high-order system, where active and reactive power controls are typically designed separately using a dual-input-dual-output model. In this letter, we introduce a complex-power-phase-angle (CPPA) model, formulated as a single-input-single-output system for grid-forming inverters. Subsequently, a complex power controller is designed. The proposed control framework allows for the unification of active and reactive power decoupling control through an order-reduced complex transfer function, enhancing the dynamic performance of GFM power control. The robustness and advantages of this method are validated through comprehensive simulation and experimental results.