A Power Decoupling Strategy for Virtual Synchronous Generator Based on Active Disturbance Rejection Control Strategy

The renewable power grid is a complex system with multiple symmetries, in which active power and reactive power play different but symmetrical roles. In weak power grid condition, the virtual synchronous generators (VSGs) are prone to large power angles and high impedance ratios in the transmission lines, leading to severe coupling between active and reactive power. This coupling causes mutual interference between the active and reactive power outputs of the VSG, increasing the dynamic oscillations and prolonging the regulation time. To solve this problem, a power decoupling strategy for VSGs based on active disturbance rejection control (ADRC) is proposed in this paper. The ADRC control decouples the VSG, a dual-input, dual-output coupled system, into two single-input, single-output systems by observing and compensating for disturbances. This approach eliminates the coupling between the VSG’s power loops without considering virtual impedance. Compared with the conventional virtual impedance power decoupling method for VSGs, the proposed ADRC strategy can deal with multi-variable systems with different orders without complex and detailed high-order models, effectively decoupling the active power and reactive power of the VSG and improving the stability of the power grid.