Integrated model of brushless wound-rotor synchronous starter-generator based on improved Parametric Average-Value Model of rotating rectifier

Brushless wound-rotor synchronous starter-generator (WRSSG) is drawing more and more attentions in aircraft power system applications because of advantages such as high safety and low cost in maintenance. Detailed analysis and optimal start control research for the WRSSG system need an accurate and time-efficient integrated model of WRSSG. Because of the presence of the rotating rectifier, there is a complex nonlinear relationship between electrical variables of the brushless exciter and main generator in WRSSG, which makes the building of the integrated model a very tough work. In this paper, an improved Parametric Average Value Model (PAVM) of the rotating rectifier with coefficients varying with load impedance and load current was proposed, and coefficients of the improved PAVM were obtained from simulations of the detailed joint Voltage-Behind-Reactance (VBR) model of WRSSG. Based on the improved PAVM of the rotating rectifier, an integrated model of the WRSSG with a two-phase brushless exciter was proposed in classic state-variable formulation. Computer studies verified that the proposed integrated model of the WRSSG is sufficiently accurate in simulations of both steady and transient states, and it is very computationally efficient compared with detailed switching models.