Research On Integrated And Coordinated Control For PMSG-base Direct-Drive WECS And Its Key Technologies

Since wind power is an inexhaustible, environment friendly and clean energy, it is paid more and more people’s attention. Direct-drive permanent magnet synchronous wind turbines will become the main model for the future development. However, it cannot be neglected that large-scale wind power of this type connected to the grid will inevitably lead to a large number of new problems. In order to reduce its negative impact on power system and achieve the harmonious development, mutual benefit and win-win progress between the wind power system and the grid, it is of great significance to research on integrated and coordinated control for PMSG-base direct-drive WECS.This paper takes PMSG-base direct-drive WECS as the research object and focuses on its integrated and coordinated control and some key technologies. First of all, the paper established the static and dynamic mathematical model of PMSG and proposed a direct parameter identification method for PMSG based on vector control. The simulation and experiment show that the parameter identification is effective, which can be used to achieve the offline parameter identification of stator resistance Rs, d-axis inductance L&, q-axis inductance Lq and the permanent magnet flux iff. Secondly, the paper established the mathematical model of the wind turbine and the converter, designed the control strategy of the wind turbine and the generator-side converter, and analysed the voltage oriented control strategy of the grid-side converter with decoupling controller. The simulation results show that the established model and its control strategy are correct and effective, and have good dynamic characteristics. Then, the paper presented the power system model with PMSG-base direct-drive wind turbines, put forward the processing method for PMSG-base WECS nodes in network equations and carried out a dynamic simulation research.Finally, due to the shortcomings of traditional control method, the paper proposed a new integrated and coordinated control method for PMSG-base WECS. For single machine infinite system and multi-machine system case, the simulation research was respectively to do. The simulation results show that the integrated and coordinated control method combined with pitch angle controller can reasonably coordinate active and reactive power output and well provide reactive power to support the node voltage which can improve the system voltage stability. What’s more, it can be beneficial to the angle stability of multi-machine system.