I/O Interface Design for FPGA Based Real-time Simulator of Active Distribution Networks

With the wide integration of distributed generators, electric vehicles and the demand side response resources, active distribution network (ADN) shows great complexity in operation mode and dynamic behavior, which bring new challenges for the real-time simulation platform in hardware-in-the-loop configuration. The FPGA based real-time simulator takes advantage of many merits of field programmable gate array (FPGA), such as small time-step, high simulation precision, rich I/O interface resources, and low cost. The I/O interface framework of the simulator was proposed to fulfil communication requirement between the simulator and external devices. A universal high-precision A/D converter interface was designed to accept signals from physical devices. A universal high-speed D/A converter interface was designed to output the result signals to physical devices, as well as a high-speed photoelectric converter interface with multiple full duplex channels was presented in application of communication between FPGA boards. A typical low voltage distribution network including photovoltaic (PV) generation unit was simulated in real-time with a time-step of 3 μs. The real world irradiance is collected by solar sensor and then imported to the simulator via A/D converter. The results of the simulator were displayed on an oscilloscope via D/A converter. Simulation results were compared with commercial off-lime simulation tool PSCAD/EMTDC to validate the correctness and effectiveness of the I/O interface design.