In the quest for a more sustainable energy future, integrating renewable energy sources like photovoltaic (PV) systems into the grid presents both opportunities and challenges. One of the significant hurdles is maintaining stability, especially when these systems are connected to weak AC grids. A groundbreaking study led by Haoli Chen from the School of Electric Power Engineering at South China University of Technology sheds new light on this issue, offering a pathway to enhance grid stability and support the growing adoption of renewable energy.
Chen and his team have focused on virtual synchronous generator (VSG) energy storage converters, which can provide crucial voltage and frequency support to the grid. However, until now, the support capabilities of these converters in weak grid scenarios have been largely unexplored. “Current research has rarely considered the support capability of VSG energy storage converters in the scenario of new energy devices connected to weak power grids,” Chen explains. This gap in knowledge is what the team aimed to address.
The researchers established small signal models for both PV and VSG energy storage systems under weak AC grids. By analyzing these models, they could comprehensively assess the impact of changes in PV output and short-circuit ratio (SCR) on system stability. The team identified high-sensitivity control parameters that significantly affect system stability and proposed a method to adjust these parameters to improve overall stability.
One of the key findings is that when the output of the PV system changes, the q-axis PI parameters of both the VSG energy storage system and the PV system exhibit high sensitivity. Similarly, changes in SCR affect the internal and external q-axis PI parameters of the VSG energy storage system. By systematically adjusting these control parameters, the researchers demonstrated improved static stability, even under challenging conditions.
The implications of this research are far-reaching for the energy sector. As the proportion of renewable energy sources in the grid continues to grow, ensuring stability becomes paramount. Chen’s work provides a practical solution for enhancing the stability of high-renewable energy grids, making it easier for energy providers to integrate more PV systems without compromising grid reliability.
The study, published in Dianli jianshe, which translates to ‘Electric Power Construction’, was verified through MATLAB/Simulink simulations. The simulations confirmed the effectiveness of the theoretical analysis, showing that the proposed parameter adjustment scheme could stabilize the system even with significant fluctuations in PV output and low SCR values.
This research paves the way for future developments in grid-forming control technologies. As energy storage systems and renewable energy sources become more prevalent, the insights from Chen’s study will be instrumental in designing more robust and stable grids. Energy providers and grid operators can leverage these findings to optimize their control parameters, ensuring a more reliable and sustainable energy future.
For the energy sector, this means not only improved grid stability but also increased confidence in investing in renewable energy projects. As the world moves towards a greener future, innovations like these will be crucial in overcoming the technical challenges associated with integrating renewable energy sources into the grid. Chen’s work is a significant step forward in this direction, offering a blueprint for enhancing grid stability and supporting the transition to a more sustainable energy landscape.
