Regulated Transformer Rectifier Unit

Driven by the demand to optimize aircraft performance, decrease operating and maintenance costs, increase dispatch reliability, and reduce gas emissions – have pushed forward the aircraft industries to the concept of more electric aircraft (MEA), and ultimately an all-electric- aircraft. More electric aircraft
applications aim for achieving a lower weight, smaller dimension, high-end efficiency, higher power density, enhanced reliability, improved EMI performance and a better environmental impact by taking the advantages of more electrical system power onboard. Inside the aircraft, different electrical parts i.e. air
compressors, wing actuators, electric brakes, air pumps, entertainment system are driven by an auxiliary DC power supply. Traditionally, a transformer rectifier unit (TRU) used to convert the three-phase AC output of the turbo generator to a regulated DC voltage. However, utilization of the bulky line frequency
transformer and large DC link capacitor, presence of third and fifth harmonic components in phase currents make the passive TRU increases the weight and size of the converter, decreases the total conversion efficiency and degrades the power quality. Therefore, our research group is looking for an alternative approach is to design a regulated transformer rectifier unit (RTRU) using an actively controlled three-phase AC-DC power factor correction (PFC) and rectification stage followed by an isolated DC/DC converter stage. An extensive research work on SiC-based, high power density, highly efficient RTRU prototypes, complying with DO-160F avionics conducted EMI standard is being carried out. Furthermore, different control techniques, soft-switching strategies, passive volume optimization methods are being explored to achieve an improved electrical performance of the RTRU. We have developed >95% efficient 5 kW (continuous) / 10kW (peak) RTRU prototype (air-cooled) satisfying different avionics standard requirements.