Abstract: With the continuous advancement of the aerospace industry, there has been a significant shift towards More Electric Aircraft (MEA). Some of the advantages of the electrification of some actuation systems in an aircraft include lower weight – hence, lower fuel consumption, – robustness, flexibility, ease of integration, and higher availability of sensors to achieve better diagnostics of the system. One cannot ignore the challenges of the electrification process, which encompasses finding appropriate hardware architectures, and control schemes, and obtaining at least the same reliability as traditional drives.

The thrust reverser actuation system (TRAS), which acts during landing to reduce the necessary runway for the aircraft to fully decelerate, has a big potential to be replaced by an electromechanical version, the so-called EM-TRAS. Among the different hardware architectures, the central-converter multi-machine (CCMM) stands out for employing a single power converter that drives multiple machines in parallel, saving weight and room usage inside the aircraft. This solution comes with its challenges related to the requirement of ensuring position synchronization among all the machines, even under potentially unbalanced mechanical loads. Since there is only one central converter, all the machines are subject to its common output, limiting the control independence of each machine. Moreover, the lack of position synchronization among the machines can cause harmful stresses to the mechanical structure of the EM-TRAS.

This work proposes a solution for position synchronization under CCMM architectures, for aerospace applications. The proposed method utilizes three-phase external and variable resistors connected in series with each of the machines, which increases the degrees of freedom (DOF) to control independently each machine under different demands. Mathematical modeling for the different components of the system is presented, from which the proposed solution is derived. Numerical simulations are used to show the working capabilities of the external resistor method. The performance of the position synchronization is enhanced via H-infinity control design methods. Hardware experiments are also presented, obtained from an experimental testbed that was partially designed and constructed during this work. Both numerical and experimental results are in agreement. Initial findings show that the method is promising and works well under some operating conditions. However, some limitations of the method are presented, such as the unstable operation under negative loads. An alternative method is described at the end of this work, which is currently under investigation by the author.

Adviser: James Cale
Co-Adviser: N/A
Non-ECE Member: Michael Kirby
Member 3: Edwin Chong
Addional Members: Peter Young

Publications:
[1] C. Lima and J. Cale. Control design for position synchronization in central converter multimachine
actuators. In Proc. of the International Conference on Electrical, Computer, Communications
and Mechatronics Engineering (ICECCME 2023), Tenerife, Spain, July 19–21, 2023
(accepted, to appear).

[2] C. Lima, Z. Miller, A. Riley, and et al. A novel electromechanical actuation testbed for emulation
of aerospace actuation systems. In 33rd Aerospace Testing Seminar, El Segundo, CA
(USA), May 15, 2023.

[3] C. Lima, J. Cale, and K. Shahroudi. Rotor position synchronization in central-converter multimotor
electric actuation systems. Energies 2021, 7485(14), Nov, 2021.

[4] C. Lima and J. Cale. Rotor position synchronization control in central-converter multi-motor
topologies. In IEEE Power and Energy Systems General Meeting, 2022, Denver, CO (USA),
July 17–21 (abstract and poster session).

[5] C. Lima, Z. Miller, R. Bushue, and et al. Testbed for emulation of aerospace actuation systems.
In Pipeline Research Council International (PRCI) Meeting, Fort Collins, CO (USA), May 10,
2022 (poster).

Program of Study:
ENGR-665
ECE-514
ECE-565
ECE-520
ECE-566
ENGR-570
MATH-580 (A3, A4, and A5)
N/A