Modeling and Analysis of Impedance of Variable Frequency AC Three-Stage Generator for More Electric Aircraft

With more electric aircraft (MEA) development, the power electronics power rating for the MEA power system is increasing. As a result, the number and power rating of the constant power loads (CPLs) in the system is gradually rising. However, the negative impedance characteristics of the CPLs may cause the system to be unstable. The impedance model of the variable frequency AC three-stage generator (VFAC-TSG), the main power supply of the MEA variable frequency AC power system, is required to analyze the stability of the MEA variable frequency AC power system. This article proposes a small-signal impedance model of the VFAC- TSG in the synchronous d-q frame. In addition, the terminal characteristics of the VFAC- TSG in open-loop and closed-loop modes are also analyzed, respectively. Finally, the proposed impedance model and analysis are verified by experiments on the hardware-in-the-loop platform.