Dynamic modeling and equivalent description of directly driven wind power system

In order to study the composite load modeling of distribution network with directly driven permanent magnet synchronous wind generators(D-PMSG),this paper described the mathematical model of it. Dual-loop control and maximum power point tracker are suitable for grid-connected D-PMSG, which was adopted to build D-PMSG power generating system in Matlab/Simulink. The analysis results of the steady and dynamic operating characteristics of D-PMSG show that, the D-PMSG can be seen as a generalized dynamic load with negative power consumption. The third order differential equations of state description equivalent model was presented. Through different disturbance levels, The validity of the equivalent model is proved from generalization, fitting degree of this equivalent description model and stability of the parameters.