Resumo:
This work, with the objective of improving the quality of electric power (QEE) in MEA (More Electric Aircraft) distribution systems operating with variable frequency (360 – 800 Hz), addresses an application of a 24-pulse converter system (SC- 24P), previously developed by the research group for use in HVDC (High Voltage Direct Current) transmission systems. Usually, the converter systems used in MEA systems, for AC–DC conversion, are of the 12-pulse type (SC-12P). However, this type of converter technically does not meet harmonic distortion standards for MEA applications and therefore must be used in conjunction with AC and DC filters. In addition, the weight and volume occupied by the filters clearly bring some disadvantages to modern MEA systems.
In order to overcome the disadvantages offered by the traditional system, this dissertation proposes the use of the SC-24P to reduce the filters used in conventional MEA systems and to improve the power quality of the system as a whole. Theoretical analyzes of the SC-24P, regarding the profiles and harmonic content of the AC currents and DC voltages for both converters, are briefly described through established equations, which made it possible to partially prove the research conducted in this dissertation. The calculations processed through the theoretical analyzes are done using the MathCad program. The advantages and performance of the employed SC-24P compared to the traditional SC-12P are exposed via computational simulations carried out in the Matlab/Simulink environment.
The results obtained from the SC-24P in terms of %THD (< 3%) of AC current, DC voltage ripple amplitude and other QEE indices, for the 360 Hz and 800 Hz frequencies, meet the RTCA-Aeronautical Standards. DO-160F and MIL-STD-704F, respectively. On the other hand, with the lack of laboratory resources regarding the availability of a power supply for the level of operational frequencies treated in simulations, a reduced-scale prototype was implemented using the power supply network at 60 Hz. The results meet the requirements of IEEE 519 and prove the application of the converter used only in industrial electrical systems, for driving rotating electrical machines. The synthesis of the results treated and discussed in this work confirms the applicability of the SC-24P in MEA systems and demonstrates a promising research to be explored for future developments.
