PV Inverter Systems Enabled by Monolithically Integrated SiC based Four Quadrant Power Switch (4-QPS)

Subhashish Bhattacharya
B. Jayant Baliga
Douglas C Hopkins

Project runs from 09/01/2018 to 12/31/2021
$1,517,146

This work brings together three innovations: Newly developed 4-Quadrant Single Die SiC-JBSFET based Power Semiconductor Switches (4-QPSs) are used to enable a new breed of Power Conversion Systems (PCS) for photovoltaic (PV) applications based on a cyclo-converter topology, and that are combined into two new module packaging schemes for creation of ultra-high density, low cost power conversion cells. Novel DC/AC power converter topologies leveraging high frequency (HF) transformer technology coupled with SiC based 4-QPS are proposed for commercial and household PV inverter applications. This combined technology development of the scalable power converter cell as a building block from the monolithic 4-QPS device die, package and converter will meet and exceed the higher efficiency, power density, specific power and relative cost metrics envisioned in the FOA. This is specifically done by innovative implementation of a SiC based 4-QPS based on monolithically integrated die which can be scaled up in current and voltage due to majority carrier characteristics. Innovative module packaging provides integration of bidirectional 4-QPS to construct power converter cells to achieve higher efficiency, power density and specific power metrics as required by the FOA. The proposed topologies can be designed to satisfy all current and emerging interconnection, interoperability, and grid support functional requirements while also achieving a combination of increased efficiency, power density, reliability, and reduced costs as compared to conventional solar inverters. The proposed module offers flexible integration of multiple types of Distributed Energy Resources including Energy Storage, Fuel Cells, and Responsive Loads on the PV plant side for optimized delivery of power to the grid. Prototype hardware will be demonstrated at power levels and voltage ratings relevant for commercial scale installations up to 50 kW using (1) newly developed SiC based 4-QPS devices (2) custom packaging of the 4-QPS (3) HF transformer technologies based upon state-of-the-art commercial magnetic cores. Simulation studies will also be performed in parallel to demonstrate the advanced grid-support features enabled by the proposed topologies. The proposed concepts leverage many recent investments and capabilities established through PowerAmerica Semiconductor Power Device Electrical Characterization Station, the NCSU FREEDM Center, X-Fab Foundry, NCSU Designed Foundry Process Developed at X-Fab, NCSU Laboratory for Packaging Research in Electronics Energy Systems (PREES) amongst others. The project scope and teaming structure seeks to transition the technologies under development to major US manufacturers to accelerate commercialization and enable successful realization of broader deployment of affordable and reliable PV-based generation throughout the US energy infrastructure.