Disturbance Decoupling in Grid-Forming Inverters for Enhanced Dynamic Response

This paper presents a control strategy for grid-forming inverters, utilizing a cascaded dual-control scheme that integrates current and voltage controllers, along with an outer loop for regulating the injected active and reactive power. The proposed approach enhances system performance by addressing key challenges faced by grid-forming inverters. One of the highlights of this strategy is the improved disturbance rejection capability of the current controller, achieved through capacitor voltage decoupling. This modification effectively reduces the impact of disturbances on system performance. Additionally, the voltage controller incorporates the concept of disturbance input decoupling, which further improves the inverter’s dynamic response under varying operating conditions. Notably, the inclusion of disturbance input decoupling enhances the loop gain of the voltage controller in the low-frequency range, leading to superior performance of the inverter. Experimental results validate the efficacy of the proposed control strategy in managing real-word scenarios such as voltage sags, load changes and variations in power references. These findings highlight the robustness of the proposed methodology, demonstrating its potential for enhancing the operation of grid-forming inverters in modern power systems.