1. Introduction

Within the modern aircraft industry, More Electric Aircraft technology is growing rapidly. Figure 1 shows a general block diagram for MEA power distributions. The power distribution system model consists of power generation unit, transformer rectifier unit, DC-DC converter unit, and DC-AC inverter unit.

The satisfactory performance of MEA depends to a very great degree on the continuing reliability of electrical systems and subsystems. This technology has many benefits and advantages such as:


© 2018 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

© The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and eproduction in any medium, provided the original work is properly cited.

Figure 1. MEA general power distribution system.

In MEA Power Electronics segment plays a very important part in controlling the energy and improving both generators and actuators energy conversion. Furthermore, in a fixed frequency system (400 Hz) a mechanical constant speed drive set between the engine and the aircraft generator, however this will give extra weight and must be frequently maintained.

The use of Power Electronics helps in reducing weight, is easier to maintain, and provides more controllability and intelligence which includes fault detection and diagnosis [1–6].

A conventional 12 pulse rectifier using Diode Bridge is one of the simplest converter since does not require any control loop, however, this type of converter has a fixed DC output with high Total Harmonic Distortion (THD) on the input current compared with the proposed 12-pulse active rectifier.

The system has the ability to stabilize an output voltage of variable Vdc from a 3 phase 360– 800 Hz, 115 V RMS system. Using a decoupling feed-forward control method by DQ frame technique, the magnitude and the phase of the input current can be controlled and hence the power transfer that occurs between the AC and DC sides can also be controlled. The converter could be suitable to use with an electric actuator (or other) aircraft loads. The system could be used as DC source for DC loads or to feed DC to AC inverter for a fixed 400 Hz supply. The design of this system poses significant challenges due to the nature of the load range and supply frequency variation and requires many features such as:

1. Sinusoidal and low harmonics contents on supply current.


Generally, use of electrical power on board is continuously increasing within the areas of communications, surveillance and general systems, such as: radar, cooling, landing gear or actuators systems. DC voltage of up to 540 V [9] may be required for electric power distribution to feed certain loads.
