Detecting Power Failure and Recovery by Grid-Connected Digital Grid Router using FPGA Control

Electricity is a necessary part of our lives. Industrial computers and control systems have high electric power quality standards because of the sensitivity to power quality disturbances. Rapid power failure detection is required to supply power continuously during power failure. An Uninterruptible Power Supply (UPS) or other systems have been proposed to prevent malfunctions such as unpredictable computer shutdowns. In this paper, we describe control flows and test results of a Digital Grid Router (DGR) by using Field Programmable Gate Array (FPGA). The DGR is a computer controlled multi-leg AC-DC-AC converter with internet communication. Our DGR has achieved 4 megahertz sampling of voltage and current data and has been developed with hysteresis current control using FPGA. This paper presents our noise robustness method for rapid grid power failure detection (a similar behavior of a UPS) and recovery, as well as seamless reconnection to the grid.