In the quest for more reliable and efficient energy systems, researchers have been exploring innovative ways to enhance the performance of microgrids. A recent study published in the International Journal of Electrical Power & Energy Systems, has introduced a groundbreaking control strategy that could revolutionize the way we manage energy storage in bipolar DC microgrids. This research, led by Yuechao Ma from the Inner Mongolia Power (Group) Co., Ltd., and the Inner Mongolia Enterprise Key Laboratory of Smart Grid Simulation of Electrical Power System, focuses on improving system inertia through hybrid energy storage systems (HESSs).
In a bipolar DC microgrid, which operates with both positive and negative voltage rails, maintaining system inertia is crucial for stability and reliability. Ma and his team have developed an optimization control strategy that addresses this challenge by integrating batteries and supercapacitors (SCs) in a novel way. “Our approach aims to solve the unreasonable power distribution problem caused by asymmetric load power on the positive and negative systems,” Ma explained. This dynamic power distribution strategy ensures that the supercapacitors can effectively improve system inertia without compromising the overall performance of the microgrid.
One of the key innovations in this research is the introduction of two operating-state discriminators for each supercapacitor. These discriminators act as smart controllers, deciding when to activate the supercapacitors to boost system inertia and when to allow them to recover. “By using these discriminators, we can avoid the influence of supercapacitors on the state-of-charge balancing of the batteries, ensuring reliable operation,” Ma added.
To further enhance the system’s inertia, the researchers introduced virtual DC generators (VDCGs) and time-varying virtual inductors. These virtual components are integrated into the output and recovery paths of the supercapacitors, respectively. The VDCGs improve the system inertia when needed, while the virtual inductors accelerate the recovery speed of the supercapacitors’ terminal voltages. This dual approach helps in maintaining the optimal operation of the entire system.
The researchers employed a particle swarm algorithm to jointly optimize the parameters of the VDCGs, addressing the trade-off between inertia improvement and dynamic response speed. This optimization ensures that the supercapacitors can repeatedly output power and improve system inertia, even under varying load conditions.
The simulation results of this study, conducted under different working conditions, demonstrated the effectiveness of the proposed control strategy. The strategy not only achieved reasonable output powers for the positive and negative HESSs but also improved system inertia and ensured the reliable operation of the supercapacitors.
The implications of this research are significant for the energy sector. As the demand for renewable energy sources grows, so does the need for efficient and reliable energy storage solutions. Bipolar DC microgrids, with their ability to handle both positive and negative voltages, offer a promising avenue for integrating renewable energy sources into the grid. The control strategy developed by Ma and his team could pave the way for more stable and efficient microgrids, enhancing the overall reliability of the energy system.
As the energy landscape continues to evolve, innovations like this will play a crucial role in shaping the future of energy storage and distribution. The work published in the International Journal of Electrical Power & Energy Systems, which translates to the International Journal of Electrical Power and Energy Systems, highlights the potential of hybrid energy storage systems in improving the performance of microgrids. With further development and implementation, this control strategy could become a cornerstone of modern energy management, driving the transition to a more sustainable and resilient energy future.
