Application of Dynamic Phasor Concept in Modeling Aircraft Electrical Power Systems

As future commercial aircraft incorporates more EMAs, the aircraft electrical power system architecture will become a complex electrical distribution system with increased numbers of power electronic converters (PEC) and electrical loads. The overall system performance and the power management for on-board electrical loads are therefore key issues that need to be addressed. In order to understand these issues and identify high pay-off technologies that would enable a major improvement of the overall system performance, it is necessary to study the aircraft EPS at the system level. Due to the switching behaviour of power electronic devices, it is very time-consuming and even impractical to simulate a large-scale EPS with some non-linear and time-varying models. The dynamic phasor (DP) technique is one way to solve that problem. This DP technique is naturally a frequency-domain analysis method and has been successfully applied in modeling of electromagnetic machines, flexible AC transmission systems etc. our previous work has extended this technique to modeling of controlled rectifier units (CRU), auto-transformer rectifier units (ATRU) etc. This paper is to summarize the DP model library developed in the University of Nottingham for accelerated simulation studies of the aircraft EPS. The three-phase models (ABC models) are used for comparative studies. The DP modeling technique is compared with the ABC model using the simulation of a twin-generator aircraft EPS, which is based on the more open electrical technology (MOET) large aircraft EPS architecture. The switching behaviour of ATRU is included in the ABC model for the EPS studies. However, the switching behaviour of PWM converters is not considered due to computation convergence problems. The efficiency and the accuracy of the DP model are demonstrated through comparison of the simulation results under normal operation conditions.