In the rapidly evolving energy sector, the integration of distributed energy resources (DERs) is challenging traditional power distribution systems. A recent study published in the journal *IEEE Access* offers a promising solution to these challenges, with implications for the future of microgrids and power electronics.
The research, led by David Cervero of the CIRCE Research Centre in Zaragoza, Spain, introduces a modular solid-state transformer (SST) designed for 3 kV DC grids. This innovation addresses the inefficiencies and control problems associated with the traditional use of alternating current (AC) in distribution systems, particularly in the context of DC microgrids.
“The growing emergence of Distributed Energy Resources (DER) that operate natively in DC challenges the traditional logic of unidirectional power flow and the exclusive use of AC in distribution systems,” Cervero explains. His team’s SST follows a four-module input-parallel, output-series configuration, enabling the creation of a 3 kV medium-voltage (MV) DC microgrid from the low-voltage (LV) AC electrical grid. This design allows for intrinsic voltage balancing among modules, straightforward scalability in both voltage and power, and easier maintenance.
The prototype achieves a power conversion efficiency of 96.4% under nominal conditions while transferring 151.6 kW, with line current total harmonic distortion (THD) remaining below 1.8%. Laboratory and field tests demonstrate continuous DC voltage regulation in a range from 1.2 kV to 3 kV, black-start capability, and support of the AC grid through reactive power.
The implications of this research are significant for the energy sector. As the integration of renewable energy sources and energy storage systems continues to grow, the need for efficient and controllable hybrid DC/AC grids becomes increasingly important. The SST developed by Cervero and his team could play a crucial role in enabling the development of such grids, addressing the lack of real demonstrators that can validate the benefits of DC integration.
“This SST, along with the constructed MV DC microgrids, addresses the lack of real demonstrators that can validate the benefits of DC integration,” Cervero notes. The modular design of the SST also offers commercial advantages, as it allows for easier maintenance and straightforward scalability, making it an attractive option for energy providers looking to modernize their infrastructure.
As the energy sector continues to evolve, innovations like the modular SST developed by Cervero and his team will be crucial in shaping the future of power distribution. By enabling the development of controllable hybrid DC/AC grids, this technology could help to integrate renewable energy sources more efficiently, reduce energy losses, and improve the overall reliability of the power grid. The research was published in the journal *IEEE Access*, a leading publication in the field of electrical and electronic engineering.