Research on Multi-VSG Parallel Control Strategy Based on Sliding Mode Active Disturbance Rejection

Abstract

To suppress the frequency oscillation phenomenon that occurs in the parallel control system of multiple virtual synchronous generators (multi-VSG) during load mutation, this paper proposes a multi-VSG parallel control strategy based on sliding mode linear active disturbance rejection (SM-LADRC). Initially, mathematical modeling of the multi-VSG parallel control system is conducted to analyze the mechanism by which load mutation affect frequency. Subsequently, based on the rotor motion equation of the VSG, linear active disturbance rejection control (LADRC) is applied to the angular frequency, and an extended state observer (ESO) is constructed to estimate and compensate for the system’s frequency state and load mutation in real time, thereby enhancing the system’s disturbance rejection capability. Concurrently, an integral sliding mode linear state error feedback (SM-LSEF) control law is formulated to rapidly adjust the frequency error control quantity, eliminating the reaching phase and accelerating the system’s response speed. Moreover, the integral sliding mode, by introducing an integral term, continuously approximates the switching function, making the sliding mode surface smoother, which effectively suppresses sliding mode chattering and improves the system’s robustness. Finally, simulation comparisons validate the correctness and effectiveness of the proposed control strategy, providing a theoretical and simulation experimental basis for engineering applications.