In the dynamic world of energy systems, the integration of renewable energy sources and energy storage systems (ESS) into microgrids is becoming increasingly crucial. A recent study published in IEEE Access, led by Yi-Hung Liao from the Department of Electrical Engineering at National Central University in Taiwan, introduces a groundbreaking power regulation strategy for bidirectional interlinking converters (BIC) in hybrid AC/DC microgrids. This innovation could revolutionize how we manage and distribute power in isolated and interconnected grid systems.
The research focuses on a control strategy that leverages grid-forming virtual synchronous generator (VSG) control of BIC to achieve global power sharing (GPS) between AC and DC sub-grids in islanded mode. This means that even when the microgrid is disconnected from the main power grid, the system can still efficiently distribute power between its different sub-grids. “The proposed control strategy not only ensures stable power distribution but also enhances the system’s resilience to faults and communication failures,” Liao explains.
One of the standout features of this strategy is its ability to operate under voltage source faults in the AC subgrid. This is a significant advancement, as it ensures that the microgrid can continue to function even if part of the system experiences a fault. The control strategy includes both communication-based and communication-less approaches, providing a robust solution for handling communication equipment failures.
On the DC side, the study introduces a droop shift control (DSC) strategy that takes into account the ESS and its management with the virtual output power method. This approach not only increases the load response on the DC side of the BIC but also allows the ESS to be charged during periods of low load demand. “By integrating the ESS with the droop shift control, we can achieve a more balanced power sharing between the AC and DC sides, optimizing the overall efficiency of the microgrid,” Liao notes.
The research also combines virtual impedance and frequency restoration control of BIC to enhance active and reactive power sharing. This ensures that the system can maintain stability and efficiency, even under varying load conditions. The feasibility of the proposed method was verified through simulations and prototype experimental results, demonstrating its practical applicability.
The implications of this research are far-reaching. For the energy sector, this could mean more reliable and efficient microgrid systems, capable of handling a wider range of operational scenarios. This is particularly relevant for remote or islanded communities that rely on microgrids for their power supply. The ability to achieve global power sharing and enhance system stability could lead to more widespread adoption of hybrid microgrids, reducing dependence on traditional power grids and promoting the use of renewable energy sources.
As the world continues to transition towards more sustainable and resilient energy systems, innovations like this one will play a pivotal role. By improving the efficiency and reliability of microgrids, this research could pave the way for a future where energy is distributed more equitably and sustainably. The study, published in IEEE Access, which translates to ‘IEEE Open Access Journal’, provides a comprehensive framework for implementing these advanced control strategies, offering valuable insights for engineers and researchers in the field.
