2results about How to "Minimize disturbance" patented technology

This invention discloses a control method for improving the transient stability of doubly-fed induction generator (DFIG) wind turbine systems connected to the grid, belonging to the fields of wind power grid connection technology and power system stability control technology. First, a reduced-order model of the system is established to accurately reflect the dynamic behavior during low-voltage ride-through. Based on this model, the attraction domain boundary and maximum power angle constraint are obtained, and then adaptive current reference control is proposed: the rotor d-axis current limit is calculated based on the maximum power angle constraint and the grid voltage, and compared with the original reference generated by maximum power point tracking. The smaller value is taken as the command to achieve adaptive limiting of the rotor current. Simultaneously, transient pitch collaborative control is proposed: the rotor speed is monitored in real time, and when the speed exceeds the safe upper limit, a transient load reduction power command is calculated and the pitch angle is rapidly increased to reduce mechanical torque. This invention can significantly enhance the fault ride-through capability and grid-connected operation reliability of DFIG wind turbines during transient processes such as voltage dips.

The utility model belongs to the seedling planting technical field especially in desert soft soil area bare root seedling quick planting tool, including the vertical rod, the outside symmetry of vertical rod has opened the small hole, the interval between corresponding one side's adjacent two small holes is equal. The present application is through setting adjusting assembly, through controlling telescopic link up and down displacement, makes the buckle with the small hole of different height cooperation under the action of spring, can adjust the distance between guide root ware and foot pedal according to need, realizes the change demand of different planting depth, through minimally invasive implantation, can realize the minimization of soil disturbance and the quick planting of bare root seedling, has promoted overall efficiency, has set up support assembly, through the synchronous rotation outward of support foot, can prevent the deflection of planting, rotates the handle and drives adjusting rod to move up and down, carries out the location to support foot, can support the vertical rod of different height, need not to bend down and pick up, the next use is convenient.