Small-signal Modeling and Output Impedance Analysis of Three Stage Brushless Synchronous Generator for More Electric Aircraft

With increased electric power replacing other secondary power in more electric aircraft (MEA), as a result, aircraft electrical power system (EPS) will face enormous challenges related to design optimization and system stability. This paper focuses on the modeling and impedance characteristics analysis of the three-stage DC generator in the 270V DC EPS for MEA, which is a critical factor in the system stability. The detailed model of the three-stage generator is derived based on the two-port network model. Then the characteristics of output impedance are analyzed and the influence of some factors including the DC-bus capacitor and control bandwidth on the output impedance is discussed. Some simulations are performed to verify the correctness of the theory.