Nonlinear Modeling and Analysis of Wound-Rotor Synchronous Starter/Generator (WRSSG) in Generating State for More Electric Aircraft

Abstract

The nonlinear modeling and analyzing of wound-rotor synchronous starter/generators (WRSSGs) plays a vital role in the analysis and monitoring of aircraft power systems. Moreover, they are of great significance with regard to the establishment of a future aircraft smart grid. However, owing to its nonlinear, high-dimensional, and strong coupling characteristics, this modeling has always remained in the frequency domain stage and the progress of more intuitive time domain modeling has been slow. This paper presents a nonlinear model of a WRSSG in a generating state. When the WRSSG is in power generation mode, most cases indicate that the aircraft is in flight mode. The establishment of the nonlinear model of the system in the power generation state is of great significance for the research of the health management and state monitoring of the aircraft power system and can improve the safety and reliability of the aircraft during flight. The model uses FE analysis and neural network to solve the nonlinear problem of the motor in the system and uses the improved variable parameter average model to solve the nonlinear problem of the rotating rectifier. According to the principle of signal transmission, a time domain model for the whole system is developed. Finally, the model is compiled by the RT-LAB real-time simulator. The nonlinear model performs well when compared with FE analysis results and tested against the MIL-STD-704F standard. The proposed nonlinear model and analysis results can be used for the condition monitoring and fault diagnosis of aircraft power systems. The hardware-in-the-loop test platform based on an accurate nonlinear model is a feasible means to study the failure of expensive equipment, and it can aid the study of irreversible failures of equipment at a low cost.