Patent ID: 11967825
Assignee: HEFEI UNIVERSITY OF TECHNOLOGY
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H  G | IPC G  H

Claim 2:
3. The stability control method for the VSG in the strong grid based on the inductance-current differential feedback according to claim 1, wherein the equation for transforming the voltages in the two-phase static coordinate system into the voltages in the two-phase rotating coordinate system in step 4 is:

Ud=cos(θPLL_Last)×Uα+sin(θPLL_Last)×Uβ

Uq=−sin(θPLL_Last)×Uα+cos(θPLL_Last)×Uβ, and

the phase-locked equation of the PLL in the single synchronous coordinate system in step 4 is:, θ
   PLL
  
  =
  
   
    U
    q
   
   ×
   
    (
    
     
      k
      p_PLL
     
     +
     
      
       k
       i_PLL
      
      s
     
    
    )
   
   ×
   
    1
    s
   
  
 

wherein, θPLL_Last is a phase angle of an A-phase voltage of the inverter-side filter capacitance obtained through the phase-locked equation of the PLL in the single synchronous coordinate system in a last computation cycle, kp_PLL is a coefficient of a proportional controller for the PLL in the single synchronous coordinate system, and ki_PLL is a coefficient of an integral controller for the PLL in the single synchronous coordinate system.