Power Quality Improvements in Aircraft Systems: A Proposal Using a 24-pulse Converter for Harmonic Mitigation

Power quality improvements and availability of electrical power are issues of great importance to aircraft systems. This paper presents an alternative 24-Pulse Converter System (CS-24P) to reduce the 11th and 13th filters in AC supply system, initially installed in traditional 12-pulse rectifiers (CS-12P) in more electric aircraft systems. The topological structure of the proposed CS-24P comprises two special three-phase three winding transformers and four 6-pulse three-phase AC-DC converters connected in series on the DC side of the system. To show the advantages of the proposed CS-24P compared with the traditional CS-12P used with AC and DC filters, computer simulations were carried out using Matlab/Simulink software to prove the theoretical analysis performed with the help of the MathCad program. The theoretical and simulation results show that the total harmonic distortion (% THD) of the input current for the CS-24P is equal to 6.60% at 60 Hz and 2.92% at 400 Hz, respectively, which meets the IEEE-519 and MIL-STD-704F requirements. Furthermore, the ripple amplitude obtained of DC voltage is less than 6 V (maximum), which meets the RTCA-DO-160F aeronautical standard. Also, it is shown that in comparison with the traditional CS-12P, the proposed CS-24P presents a satisfactory performance in terms of % THD of AC current and voltage, power factor, ripple amplitude (peak to mean) and ripple factor of DC voltage. A laboratory prototype was designed and executed using available laboratory resources to validate the research. The obtained results confirm the technical feasibility and applicability of the proposed prototype in aircraft systems.