Patent ID: 11939961
Assignee: SHANDONG UNIVERSITY
Field: Engines, pumps, turbines (Mechanical engineering)
Classification: CPC F  H  Y | IPC F  H

Claim 0:
1. A method for positive and negative sequence rotor currents control of a doubly-fed wind turbine generator under a single dq control structure, comprising:
extracting positive and negative sequence components of a stator terminal voltage of a doubly-fed wind turbine generator;
tracking and phase locking the positive sequence components of the stator terminal voltage;
adjusting a reference value r_ref−*− of a negative sequence rotor current according to the negative sequence stator terminal voltage to obtain a reference adjustment value of the negative sequence rotor current, a conversion formula for adjusting is:, I
     r
    
    
     r_com
     
      -
      *
     
    
    -
   
   =
   
    
     
      
       I
       ⊥
      
      
       r_ref
       
        -
        *
       
      
      -
     
     -
     
      
       K
       
        U
        neg
       
      
      ⁢
      
       
        U
        ⊥
       
       
        s
        
         -
         *
        
       
       -
      
     
    
    
     K
     
      r
      ⁢
      e
      ⁢
      f
     
    
   
  
  ,
 

wherein, r_com−*− is the reference adjustment value, r_ref−*− is the negative sequence rotor current reference value, the Kref and KUneg depend on parameters of the doubly-fed wind turbine generator, and vary with ωPLL and ωr, and need to be updated in real time according to the ωPLL and ωr, wherein ωPLL is a rotational speed of a forward-rotating dq coordinate system, and ωr is the rotational speed of a rotor; {right arrow over (I)}r_ref−*−
superimposing the reference adjustment value of the negative sequence rotor current with a reference value of a positive sequence rotor current in the forward-rotating dq coordinate system as an input to a PI current feedback control function in the forward-rotating dq coordinate system; and
controlling turn-on and turn-off of a switching device by using a switching signal of a rotor-side converter obtained from the PI current feedback control function, then controlling a output voltage of the rotor-side converter.