All research starts with simulation. Our faculty and students are adept at using multiphysics software to evaluate electrical, thermal and magnetic design impacts. In addition to traditional power system models of standard problems, we’re integrating results from multiple platforms to show the complete picture for real feeders on real grids. OpenDSS linked to CYME, RTDS linked to OPAL-RT and multiple connected FREEDM System grids? Done.
Power Electronics Packaging
Wide Band Gap semiconductors are opening new options for circuit design with higher voltages and higher switching frequencies. But these devices still require proper thermal management and electromagnetic isolation for optimal performance. We’re using 3D printing, UV curable resins, proprietary encapsulants and novel material combinations to design better packages for power electronics. Some of this work is done on our Hesse Mechatronics High Precision Programmable Wire Bonder and a Torch Pick-and-Place Machine.
Green Energy Hub
Housed in the Keystone Science Center on NCSU’s Centennial Campus, this 12 kV loop rated for 1 MW has five connection nodes for demonstrating the full FREEDM system. This high bay lab space currently houses multiple projects and research areas but can also accommodate commercial products for testing and evaluation with the FREEDM plug and play design. Our hub also connects 40 kW of rooftop photovoltaics with four electric vehicle charging stations and an outdoor pad for evaluating the full range of renewable energy technologies.
Real Time Digital Simulation
FREEDM has two RTDS facilities, each with unique features. At Florida State University, we use a 14 rack system linked by fiber optics to multiple high power stations for conducting Hardware-in-the-Loop (HIL) simulations. Our EMS/SCADA incorporates Rockwell PLCs and SEL and Beckwith relays. This lab includes a motor drive testbed with a 5 megawatt, two stage gearbox capable of 24,000 rpm. This lab recently conducted HIL testing of the Generation 3 Solid State Transformer.
NC State University is home to our other RTDS lab. In addition to various switches and relays that can be included in the system, we’ve also synchronized our RTDS units with our OPAL-RT system. Though smaller that the lab at FSU, we’re using the latest PB5 cards from RTDS and a 12 core, OP5600 rack from OPAL-RT. Using Modular Multilevel Converter topology, we’re simulating multi-terminal High Voltage DC systems.
Both labs have been used to simulate implementation scenarios for the FREEDM System and provide feedback to technology designers for improving system performance. We’ve also used this equipment to help design the all-electric warship for the US Navy, solve grid stability issues for the Western Electric Coordinating Council and conduct research for the Advanced Research Projects Agency for the Department of Energy (ARPA-e).
Transient Network Analyzer
Although digital simulators are now prevalent, we still maintain our electromagnetic analog for studying particular power systems. Our system has been used for performance evaluation of voltage source converter solutions on a reduced 3 phase network that included generators, transmission line models and transfer impedances between buses.