Optically Isolated High Voltage Integrated Gate Biopolar Transition-Based 5-MW Cascaded Inverter for Distributed Energy Resources (DER) Applications

65892 High power applications typically use power converters that are large, expensive, difficult to control, and present significant engineering challenges as power density and power capacity increase. Gate Turn Off thyristor systems, including variants that utilize Emitter Turn Off thyristors and Integrated Gate Commutated thyristors, exhibit slow switching speeds, have poor reverse bias safe operating area, and require high gate currents to turn the devices off. These traits limit their usefulness in high power applications, especially where higher switching frequencies are desired. This project will develop an optically isolated, mega-watt level, cascaded inverter based upon recent advances in optical sensors, optical interconnects, and High-Voltage Integrated Gate Bipolar Transistors (HV-IGBTs). In Phase 1, a prototype full-bridge megawatt inverter was developed, based upon newly available HV-IGBTs, and combined with optical sensing, interfacing, and control. Design parameters were established for maximum voltages, currents, harmonics, and switching frequencies. Phase II will develop a prototype, full-bridge, megawatt inverter with greater than 98% efficiency, and with higher reliability and a smaller footprint compared to thyristor inverters. Commercial Applications and Other Benefits as described by the awardee: The modularized HV-IBGT inverter should offer significant benefits over the conventional thyristor-based inverter, reducing productivity losses due to ¿voltage sags¿ and momentary outages that affect most industrial and commercial customers such as semiconductor manufacturers, telecommunications, banks, restaurants, and hospitals. These productivity losses exceed $10 billion/year in the U.S. alone.