Design and Integration of DC Power System with Regulated Transformer Rectifiers 2002-01-3186

New trends in design of electric power systems for the next generation of aircraft, (more electric aircraft, variable frequency electric power systems, etc.), require new technologies for DC power supply and AC/DC conversion. Advancement in power electronics and in power distribution technologies favor the development of concepts of power distribution and conversion with improved electric power performances.

This paper presents the main characteristics and performances related to design and integration of the Honeywell Regulated Transformer Rectifier Unit (RTRU) in a DC electric power system. The design requirements for this new concept RTRU were developed from studies and analysis of existing and foreseen future power systems needs. Conclusions and recommendations on the use and integration of the RTRU were developed based on studies, simulation, analysis and testing. The testing was performed as part of the RTRU integration in a Laboratory Test Rig replicating a fully integrated Variable Frequency electric power system of a commercial aircraft. The multi-functional RTRU presented is the result of Honeywell's research and development programs oriented to the next generation of more electric aircraft. Novel features offered by the use of the Honeywell designed RTRU in an integrated DC Generating system include: voltage regulation of the DC Bus, controlled APU start via current control capabilities, optimized charge schedule for batteries (charging algorithm) and finally enabler for the implementation of No-Break-Power-Transfer in the DC Subsystem. The benefits offered by the integration of the RTRU in a DC Subsystem will be reflected in increased dispatch reliability, lower overall weight, lower cost of ownership, lower Direct Maintenance Cost, compared with present DC systems.

The object of this paper is to present technical aspects related to the use of the RTRU in a DC Power Subsystem.