Controller and method for simulating active power frequency of double-fed induction generator (DFIG) in combination with inertia and over speed

Abstract

The invention discloses a controller and method for simulating the active power frequency of a double-fed induction generator (DFIG) in combination with inertia and over speed. The controller comprises a frequency deviation detecting module, a blocking module, a regulating variable setting module, a time delay module and a speed protecting module which are connected in sequence, wherein a real-time grid frequency signal and a frequency setting value are respectively input in the frequency deviation detecting module to obtain the frequency deviation signal of the grid at that time; the frequency deviation signal enters the regulating variable setting module through the blocking module, and the regulating variable setting module obtains a speed regulating variable according to the frequency deviation signal; and the speed protecting module enables the DFIG unit to exit frequency modulation under an abnormal speed condition, and can put into the frequency modulation again after time delay for a period of time. The controller has the beneficial effects that large-scale double-fed wind power integration takes the place of a conventional synchronous generator to cause that the system inertia is reduced and thus the transient stability of system frequency is worsened, and the comprehensive frequency controller provided by the invention can effectively solve the problem.

Description

technical field [0001] The invention relates to the technical field of doubly-fed wind power generators, in particular to a doubly-fed wind turbine active frequency integrated controller and method that combines simulated inertia and overspeed method control. Background technique [0002] As the most mature new energy power generation method with the most conditions for large-scale development at present, wind power generation has an increasing penetration rate in the power system, especially in regions rich in wind energy resources. The rapid development of wind power generation has brought huge environmental and economic benefits, but it also brings new challenges to the safe and stable operation of the power system. [0003] Doubly fed induction generation (DFIG) has the characteristics of high power generation efficiency and small inverter capacity, and has become one of the main models of large wind farms. While its power electronic converter achieves maximum power tra...

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Problems solved by technology

[0008] The DFIG unit has a large inertia and a wide range of speed adjustment, so the above method can theoretically simulate a larger "simulated inertia" than the synchronous motor; however, the kinetic energy that the DFIG unit can provide is limited when the speed is low, and the speed recovery process after exiting frequency regulation The reduction of output power will cause a secondary drop in grid frequency, and the deviation of the operating point from the maximum power tracking point during frequency regulation will also aggravate this adverse effect

Moreover, the perfect frequency regulation capability of wind farms requires wind turbines to have both controllable inertial response and primary frequency regulation capability, and a comprehensive control method that organically combines primary frequency regulation and inertial control after load shedding is relatively rare

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