An electromechanical transient model of direct-driven permanent magnet synchronous generator based wind power system

This paper proposes a method for an electromechanical transient model of direct-driven permanent magnet synchronous generator (D-PMSG) based wind power system, for analyzing the impact on stability and security of grid power system. The generator, with its converter control system based on dq decoupling strategy, is greatly simplified. And the same goes for the grid side converter and control system. Meanwhile, the dynamic process of DC voltage and braking resistor are taken into account, which reveal the operation characteristic of low voltage ride through process. As for the other parts of D-PMSG, they are established in a mathematical way. Finally, the order of the proposed electromechanical transient model is greatly decreased into eight order. Simulations in the single machine infinite bus system are carried out after all models are established in PSASP UD plat. Simulation results demonstrate that the proposed model can describe the electromechanical transient characteristics of the wind power system.