Determination Methodology for Stability Domain of Hybrid Electric Power System with Multiple Excitation Sources

Abstract

Irregular internal excitation (engine excitation and motor excitation) and external load excitation can cause torsional vibration in hybrid electric propulsion system which even leads to the break of shaft. The objective of this paper is to determinate the stability domain of hybrid electric power system under different drive mode with multiple excitation sources. To achieve the goal, the simplified three-mass torsional model of hybrid electric power system is established. Then we apply the multi-scale method to solve the nonlinear torsional model. Finally we set different parameters of engine speed to simulate torsional vibration characteristics of hybrid electric power system. The simulation results exhibit that the torsional vibration characteristics of hybrid electric power system under two drive mode are different because the directional relationship of the moment of engine and permanent magnet synchronous motor (PMSM) is distinctive. It’s hard to eliminate the torsional vibration of hybrid electric propulsion system due to phase difference between the engine excitation and the load excitation.