Real-time simulation of airplane power distribution system

Abstract

Airplane power distribution system is developing rapidity in recent years. The concept

of a "more electric aircraft (MEA)" and "all electric aircraft (AEA)" represent the

trends of airplane power distribution system in the future.

Simulation is very important in the design of airplane power system. As a certain type

of simulation, real-time simulation runs in discrete-time and fixed time step. As the

name suggests, real-time simulation runs in the same pace as clock time, which makes

rapid control prototyping and hardware in the loop simulation possible on real-time

simulators.

In this project, real-time simulation is implemented on the modeling of the airplane

power system. The complete model of the airplane is built with Simulink, and then

simulated on Opal-RT real-time simulators with the assistance of RT-Lab software. The

power system model consists of generators, power distribution lines, auxiliary power

units, transformer and rectifier units and the loads on both ac and dc buses.

The simulation result revealed that it is feasible to run a real-time simulation on

airplane power system. However, airplanes commonly use 400Hz ac power system

with a great number of power electronic devices adopted. For that reason, the time step

must be set extremely small to maintain accuracy in a discrete time simulation. Thus

the requirement for the performance of hardware is excessively high in airplane power

system simulation. In this project, due to the limitation of hardware, the whole system

is separated the power system into smaller scale ones during simulation.

The simulation result is reasonable when the time step is set to 0.05 millisecond, and the number of overruns occurred in simulation is acceptable. In further research, it is

highly recommended to implement real-time simulation only on single component

(control unit, power electric devices, etc.) instead of the whole power system.