750kW AC-link power converter for renewable generation and energy storage applications

Widespread deployment of photovoltaic (PV) and wind energy systems, with their associated variability, will require the addition of local energy storage in order to level out the power delivered to the utility. The fast power ramp rates experienced by PV and wind, however, require rapid response times and tight integration with co-located energy storage systems. This paper presents a novel three-port 750kW AC-link power converter which ties together a renewable generation source, an energy storage system, and a grid connection. The system enables sub-millisecond response times to power transients, energy capture during grid low-voltage ride-through conditions, direct voltage transformation using a 50kHz high-frequency nanocrystalline transformer, and 3MW/m³ power density. A prototype system developed for Naval applications that uses 6kV silicon carbide GTOs provides an example of the technology´s capabilities.