Method and system for controlling the active power output of a wind farm

Patent metadata

Field	Value
Publication number	US-10557457-B2
Application number	US-201815919843-A
Country	US
Kind code	B2
Filing date	Mar 13, 2018
Priority date	Mar 13, 2017
Publication date	Feb 11, 2020
Grant date	Feb 11, 2020

Abstract

A method for controlling an active power in a wind farm comprises inputting an active power setpoint value into the wind farm model. Splitting the active power setpoint value of the wind farm among models of the wind turbines. Determining a modeled active power setpoint value of the wind farm as a sum of modeled active power setpoint values of the wind farm model. Determining a system deviation as a difference between the modeled active power setpoint value and an actual value of the active power output of the wind farm. Inputting the system deviation into a power controller which outputs a controller manipulated variable. Determining a feedforward controller manipulated variable independently of operating states of the wind turbines of the wind farm or the active power. Determining an overall manipulated variable as the sum of the freeforward controller manipulated variable (uff) and the controller manipulated variable.

First claim

The invention claimed is:

1. A method for controlling active power output (P act ) in a wind farm having at least two wind turbines, each having a wind turbine controller to control power output for each of the at least two wind turbines, the method comprising:
inputting an active power setpoint value (P set , P set,global ) of the wind farm into a wind farm model;
splitting the active power setpoint value (P set , P set,global ) of the wind farm among models of each of the at least two wind turbines;
determining a modeled active power setpoint value (P′ set ) of the wind farm as a sum of modeled active power setpoint values (p simO,1 , p simO,2 , p simO,n ) of the wind farm model, wherein the modeled active power setpoint values (p simO,1 , p simO,2 , p simO,n ) depend on a portion of the active power setpoint values (p simI,1 , p simI,2 , p simI,n ) apportioned to the respective models of each of the at least two wind turbines;
determining a system deviation (e) as a difference between the modeled active power setpoint value (P′ set ) and an actual value of the active power output (P act ) of the wind farm;
inputting the system deviation (e) into a power controller which outputs a controller manipulated variable (u reg );
determining a feedforward controller manipulated variable (u ff ) independently of operating states of the at least two wind turbines of the wind farm or the actual value of the active power output (P act ); and
determining an overall manipulated variable (u) as a sum of the feedforward controller manipulated variable (u ff ) and the controller manipulated variable (u reg ).

2. The method of claim 1 , wherein behavior of the wind farm is represented by the models of each of the at least two wind turbines.

3. The method of claim 1 , wherein the overall manipulated variable (u) is split into manipulated variables for individual wind turbines (u WT,1 , u WT,2 , u WT,n ).

4. The method of claim 1 , wherein at least one state variable (S 1,1 , . . . , S 1,k , S n,1 , . . . , S n,k ) of one of the at least two wind turbines is present in the respective model of one of the at least two wind turbines in order to minimize a deviation between the actual active power value of the at least two wind turbines (n act,1 , p act,2 , p act,n ) and the modeled active power setpoint values (p simO,1 , p simO,2 , p simO,n ) of the wind farm model.

5. The method of claim 4 , wherein the at least one state variable of each individual wind turbine comprise information about rotational speed.

6. The method of claim 1 , wherein the models of each of the at least two wind turbines of the wind farm represent configuration parameters of each individual wind turbine.

7. A wind farm control system for a wind farm having at least two wind turbines and a setpoint value for an active power (P set , P set,global ) for controlling the at least two wind turbines that is configured to be output by the wind farm and input into the wind farm control system, the wind farm control system comprising:
a feedforward control unit configured to determine a feedforward control manipulated variable (u ff ) independently of operating states of the at least two wind turbines of the wind farm and an actual value of the active power (P act );
a wind farm model configured to output a modeled active power value (P′ set ) of the wind farm from the setpoint value for the active power (P set , P set,global );
a subtraction unit configured to determine a system deviation (e) from a difference between the modeled active power value (P′set) of the wind farm and the actual value of the active power (P act ) output by the wind farm;
a power controller configured to determine a controller manipulated variable (u reg ) based on the system deviation (e); and
a summation unit configured to determine an overall manipulated variable (u) as the active power setpoint value for the wind farm from a sum of the feedforward control manipulated variable (u ff ) and the controller manipulated variable (u reg ),
wherein the wind farm model comprises wind turbine models for each of the at least two wind turbines, and
wherein a portion (p simI ) of the actual value of the active power (P act ) to be output by the wind farm is input into each model of the at least two wind turbines, and wherein each wind turbine model is configured to determine a modeled active power setpoint value of the active power (p simO ) to be output by an individual wind turbine.

8. The wind farm control system of claim 7 , further comprising a first apportioning unit configured to distribute the setpoint value for the active power (P set ) of the wind farm to the models of each of the at least two wind turbines of the wind farm.

9. The wind farm control system of claim 8 , further comprising a second summation unit configured to sum together the modeled active power setpoint values (p simO,1 , p simO,2 , p simO,n ) for the models of the at least two wind turbines, wherein the sum is input into the subtraction unit.

10. The wind farm control system of claim 8 , further comprising a second apportioning unit configured to distribute the overall manipulated variable (u) to manipulated variables for individual wind turbines (u WT,1 , u WT,2 , u WT,n ) of the wind farm.

11. The wind farm control system of claim 7 , wherein at least one state variable (S 1,1 , S 1,k , S n,1 , . . . , S n,k ) of one of the at least two wind turbines is input into a respective model of one of the at least two wind turbines in order to minimize a deviation between the actual active power value of an individual wind turbine (p act,1 , p act,2 , p act,n ) and the modeled active power value (p simO,1 , p simO,2 , p simO,n ) of the individual wind turbine.

12. The wind farm control system of claim 11 , wherein the at least one state variable of each individual wind turbine comprises information about rotational speed.

13. The wind farm control system of claim 7 , wherein the models of each of the at least two wind turbines of the wind farm represent configuration parameters of each individual wind turbine.

Assignees

• Nordex Energy Gmbh
• Nordex Engery GmbH

Inventors

• Drossel Detlef
• Bode Florian

Classifications

• H02J2103/30

  Simulating, planning, modelling, reliability check or computer assisted design [CAD] of electric power networks · CPC title

• F03D7/045

  with model-based controls · CPC title

• F03D7/048 Primary

  controlling wind farms · CPC title

• F05B2270/335

  Output power or torque · CPC title

• H02J3/38

  Arrangements for feeding a single network from two or more generators or sources in parallel; Arrangements for feeding already energised networks from additional generators or sources in parallel · CPC title