Rodney McGee

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Single element 33×33 μm² InAs/GaSb superlattice light-emitting diodes (SLEDs) operating at 77 K with peak emission at approximately 4.6 μm are demonstrated. A peak radiance of 2.2 W/cm²/sr was measured corresponding to an apparent temperature greater than 1350 K within the 3-5 μm band. A 48 μm pitch, 512 × 512 individually addressable LED array was fabricated from a nominally identical SLED wafer, hybridized with a read-in integrated circuit, and tested. The array exhibited a pixel yield greater than 95%.

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The CVORG group at the University of Delaware is responsible for designing and developing a test platform for the operation and characterization of a 512×512 array of infrared LED emitters. This platform consists mainly of an integrated circuit responsible for driving current to the LEDs, a package to which the driver and LEDs can be mounted, and a cryogenic dewar used to run tests at 77K. The fabrication of the driver read-in integrated circuit, or RIIC, was completed using a 0.5μm CMOS process from OnSemiconductor. Because of the size of the array, stitching techniques were used to create the 3.3cm×3.3cm chip. The cryogenic package is a custom 6-layer printed circuit board (PCB) plated in a soft wire-bondable gold. Finally, modifications were made to the cryogenic dewar to allow us to properly interface with the RIIC.

512 Individually Addressable MWIR LED Arrays Based on Type-II InAs/GaSb Superlattices

The demand for high-speed and/or high-temperature infrared (IR) scene projectors has led to the development of systems based on IR light-emitting-diode (LED) arrays. Using mid-wave (3--5 μm) superlattice LED arrays, a 512 × 512 pixel scene projection system operating at 100 Hz has been fully developed. These LEDs, flip-chip bonded to a read-in integrated circuit, display temperatures of up to 1350 K when cooled to liquid nitrogen temperature (77 K). Using custom drive electronics and packaging, the array has been nonuniformity corrected (NUCed) and has survived hundreds of hours of operation at multiple facilities. This system is fully configurable by the user and has a digital visual interface to display content.

System for driving 2D infrared emitter arrays at cryogenic temperatures

With increased focus on intermittent renewable energy sources such as wind turbines and photovoltaics, there comes a rising need for large-scale energy storage. The vehicle to grid (V2G) project seeks to meet this need using electric vehicles, whose high power capacity and existing power electronics make them a promising energy storage solution. This paper will describe a charging system designed by the V2G team that facilitates selective charging and backfeeding by electric vehicles. The system consists of a custom circuit board attached to an embedded linux computer that is installed both in the EVSE (electric vehicle supply equipment) and in the power electronics unit of the vehicle. The boards establish an in-band communication link between the EVSE and the vehicle, giving the vehicle internet connectivity and the ability to make intelligent decisions about when to charge and discharge. This is done while maintaining compliance with existing charging protocols (SAEJ1772, IEC62196) and compatibility with standard “nonintelligent” cars and chargers. Through this system, the vehicles in a test fleet have been able to successfully serve as portable temporary grid storage, which has implications for regulating the electrical grid, providing emergency power, or supplying power to forward military bases.

512

Large IR detector arrays, particularly ones intended for military and aerospace applications, are often difficult and expensive to directly test. These detectors require an IR projector for scene simulation. Current methods for testing such sensors rely heavily on expensive field test programs and/or utilize lower performance thermal emission-based IR scene projectors. Recently there has been increased interest and development of seminconductor-based infrared (IR) LED-based emitter array devices (e.g. SLEDS), due to their ability to produce higher apparent temperatures, lower background temperatures, and much faster rise and fall times than thermal emission techniques. These devices flip-chip a large CMOS driver chip onto a two-dimensional array of IR emitter devices typically fabricated on a GaSb substrate. Several testing sessions showed the unique functionality and capabilities in several important areas such as: apparent temperature exceeding 1000 Kelvin, rise and fall time of 3–4 microseconds, and low apparent background temperatures. Unfortunately, SLEDS arrays require the removal of kW-level heat fluxes while being maintained at liquid-nitrogen temperatures. Although multiple project for construction of these IR emitter arrays are underway, currently there appears to be no cooling system available to operate these arrays at the performance level that they are capable of achieving.

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This report summarizes the activities and accomplishments of a two-year DOE-funded project on Grid-Integrated Vehicles (GIV) with vehicle to grid power (V2G). The project included several research and development components: an analysis of US driving patterns; an analysis of the market for EVs and V2G-capable EVs; development and testing of GIV components (in-car and in-EVSE); interconnect law and policy; and development and filing of patents. In addition, development activities included GIV manufacturing and licensing of technologies developed under this grant. Also, five vehicles were built and deployed, four for the fleet of the State of Delaware, plus one for the University of Delaware fleet.