This paper studies on the change mechanisms of the voltage stability caused by the grid connection of front-end speed-controlled wind turbines(FSCWT)integrating into power system.First of all,the differential algebrai...This paper studies on the change mechanisms of the voltage stability caused by the grid connection of front-end speed-controlled wind turbines(FSCWT)integrating into power system.First of all,the differential algebraic equations describing the dynamic characteristics of wind turbines are illustrated.Then,under the guidance of IEEE3 node system model,the influence of the angular velocity of wind turbines,the reactive power and the active power at load bus on the voltage stability of grid-connection has been analyzed by using bifurcation theory.Finally,the method of linear-state feedback control has been applied to the original system in accordance with the bifurcation phenomenon of grid-connected voltage caused by the increase in the active power at load bus.Research shows that voltage at the grid-connected point would be changed with the fluctuation of turbines angular velocity.And increasing its reactive power can enhance voltage at the grid-connected point;problem of bifurcation at the grid-connected point can be delayed when increasing the gain k s of feedback controller within a certain range.展开更多
Mechanical gearboxes are typically employed with doubly-fed induction generatur-based wind turbines. The main drawback of this solution is the gearbox＇s reliability and maintenance. Using magnetic gearbox in conjunct...Mechanical gearboxes are typically employed with doubly-fed induction generatur-based wind turbines. The main drawback of this solution is the gearbox＇s reliability and maintenance. Using magnetic gearbox in conjunction with the doubly-fed induction generator is an emerging alternative being promoted by the research community which maintains the reduced size doubly-fed machine and overcomes the mechanical gearbox problems reported by field experience. This paper proposes a novel magnetic gearbox configuration in which a conventional planetary magnetic gearbox is equipped with n-phase coils fitted around the ferromagnetic pole-pieces to extract output electrical power. The turbine mechanical power is thus divided into mechanical power to drive the electrical generator and extra electrical power that can be diverted into a storage system to perform the power leveling function. The proposed configuration can also be used to freely modify the power-speed characteristic as seen by the electrical generator, a highly needed feature for grid frequency support.展开更多
基金National Natural Science Foundation of China(No.61663019)
文摘This paper studies on the change mechanisms of the voltage stability caused by the grid connection of front-end speed-controlled wind turbines(FSCWT)integrating into power system.First of all,the differential algebraic equations describing the dynamic characteristics of wind turbines are illustrated.Then,under the guidance of IEEE3 node system model,the influence of the angular velocity of wind turbines,the reactive power and the active power at load bus on the voltage stability of grid-connection has been analyzed by using bifurcation theory.Finally,the method of linear-state feedback control has been applied to the original system in accordance with the bifurcation phenomenon of grid-connected voltage caused by the increase in the active power at load bus.Research shows that voltage at the grid-connected point would be changed with the fluctuation of turbines angular velocity.And increasing its reactive power can enhance voltage at the grid-connected point;problem of bifurcation at the grid-connected point can be delayed when increasing the gain k s of feedback controller within a certain range.
文摘Mechanical gearboxes are typically employed with doubly-fed induction generatur-based wind turbines. The main drawback of this solution is the gearbox＇s reliability and maintenance. Using magnetic gearbox in conjunction with the doubly-fed induction generator is an emerging alternative being promoted by the research community which maintains the reduced size doubly-fed machine and overcomes the mechanical gearbox problems reported by field experience. This paper proposes a novel magnetic gearbox configuration in which a conventional planetary magnetic gearbox is equipped with n-phase coils fitted around the ferromagnetic pole-pieces to extract output electrical power. The turbine mechanical power is thus divided into mechanical power to drive the electrical generator and extra electrical power that can be diverted into a storage system to perform the power leveling function. The proposed configuration can also be used to freely modify the power-speed characteristic as seen by the electrical generator, a highly needed feature for grid frequency support.
