MDT-MVMD-based frequency modulation for photovoltaic energy storage systems

Due to the rapid advances in renewable energy technologies, the growing integration of renewable sources has led to reduced resources for Fast Frequency Response (FFR) in power systems, challenging frequency stability. Photovoltaic (PV) plants are a key component of clean energy. To enable PV plants to contribute to FFR, a hybrid energy system is the most favorable candidate, and its power sharing algorithm significantly influences the FFR capability of PV plants. In this study, a model is established for a Virtual Synchronous Generator Hybrid Energy Storage System (VSG HESS). In addition, the mechanism by which PV plants participate in fast frequency regulation is analyzed. Subsequently, a novel multi-dimensional time filtering algorithm is proposed to overcome the problems associated with the short frequency sampling periods and insufficient measurement data in PV plants. Specifically, the techniques of Multi-Delay embedding Transform (MDT), Tucker decomposition, and Multivariate Variational Modal Decomposition (MVMD) are integrated into a unified framework for improved frequency resolution prior to frequency division. Finally, the effectiveness of the proposed method is validated through online simulations performed on a VSG-controlled PV storage microgrid platform. Simulation results reveal that the proposed method is able to outperform conventional filtering algorithms in terms of frequency division accuracy and calculation speed.