DOE OSTI2013
Seedling funding was secured through the ARPA-E program to develop a robust, utility-scale Power Converter Augmented Transformer (PCAT). The project designed, fabricated, and tested two 13 kV, 1 MW PCATs operating at an effective switching frequency of up to 50 kHz and at an efficiency of greater than 99%. Two versions of the PCAT were fabricated – one using an imputed DC link (IDCL) topology and the other using a back-to-back (BTB) topology. The IDCL avoids the use of electrolytic capacitors for bulk energy storage, thus improving the lifetime and decreasing the size of the converter, while the BTB topology uses an industry-proven topology that is more commercially viable in the short term. To give the PCAT a lifetime and maintenance profile compatible with typical existing utility assets, a novel Passive Thermal Management System (PTMS) was designed and integrated into both PCATs. The PTMS uses a thermosiphon to remove heat from the power electronic devices without forced cooling and reject it to the ambient environment. In addition, a fail-normal feature was implemented to ensure that in the event of PCAT failure the functionality of the underlying transformer is retained. Attainment of project objectives was verified through testing at the Georgia Tech National Electrical Energy Testing Research and Applications Center (NEETRAC). The IDCL-based PCAT had an efficiency of more than 99.10% and the BTB-based PCAT had an efficiency of more than 99.75%. During testing, the PTMS exceeded project requirements by rejecting the 5 kW output of the converters to a 40 °C environment while keeping devices junction temperatures within their tolerances.
24 POWER TRANSMISSION AND DISTRIBUTION↗