In collaboration with the National Institute of Advanced Industrial Science and Technology (AIST) Group, including AIST Solutions Co., Ltd., we conducted a prototype validation of the Digital Grid Router (DGR) with Grid Forming functionality in January 2024. The testing took place at the Fukushima Renewable Energy Institute.

During the validation at the Fukushima Renewable Energy Institute, we operated six Digital Grid Routers DGRs (three 20kW units and three 10kW units) in parallel, directly connected to a simulated power source. We evaluated the frequency response, voltage response, and voltage dips, confirming that all units performed according to design specifications.

Additionally, we conducted Power Hardware-In-the-Loop (PHIL) tests using FREA’s Digital Real-Time Simulation (DRTS). The tests involved interconnecting six DGR units through a power amplifier to a grid model and assessing the behavior of the frequency change rate when part of the power source on the grid model was dropped. The tests confirmed that the grid could operate stably post-dropout in scenarios where the DGRs constituted 20% to 80% of the grid source. Detailed results of these tests are currently under review and are planned for publication in academic papers.

We are also in the process of procuring the same DRTS equipment and power amplifiers used by FREA, and plan to establish our own PHIL testing environment at our R&D Center (Tokyo Ryutsu Center) within this year. Moving forward, we will conduct PHIL tests at our R&D Center to evaluate and improve DGR performance more efficiently.