Patent ID: 11874336
Assignee: WUHAN UNIVERSITY
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 3:
4. The method according to claim 1, wherein Step (3) comprises:
dividing the fault sections into a current zero zone and a current non-zero zone, and setting different diagnosis thresholds THXY(k) for different sections:, T
    ⁢
    
      
        H
        
          X
          ⁢
          Y
        
      
      ⁡
      
        (
        k
        )
      
    
  
  =
  
    {
    
      
        
          
            
              
                
                  
                    V
                    DC
                  
                  ⁡
                  
                    (
                    k
                    )
                  
                
                4
              
              -
              V
            
            ,
          
        
        
          
            
              
                I
                
                  X
                  ⁢
                  Y
                
              
              ⁡
              
                (
                k
                )
              
            
            =
            0
          
        
      
      
        
          
            
              
                
                  
                    V
                    DC
                  
                  ⁡
                  
                    (
                    k
                    )
                  
                
                2
              
              -
              V
            
            ,
          
        
        
          
            
              
                I
                
                  X
                  ⁢
                  Y
                
              
              ⁡
              
                (
                k
                )
              
            
            =
            1, for a fault diagnosis of the internal switching transistor, where V is a preset value, which is a constant; IXY(k)=0 represents that IX or IY is in the current zero zone, IXY(k)=1 represents that IX and IY are both in the current non-zero zone, and VDC(k) is the direct current side voltage of the rectifier at the current time; and
providing a following definition:, I
      
        X
        ⁢
        Y
      
    
    ⁡
    
      (
      k
      )
    
  
  =
  
    {
    
      
        
          
            0
            ,
          
        
        
          
            
              
              
                
                  I
                  X
                
                ⁡
                
                  (
                  k
                  )
                
              
              
            
            ≤
            
              
                I
                
                  T
                  ⁢
                  H
                
              
              ⁢
              
                
              
              ⁢
              or
              ⁢
              
                
              
              ⁢
              
                
                
                  
                    I
                    Y
                  
                  ⁡
                  
                    (
                    k
                    )
                  
                
                
              
            
            ≤
            
              I
              
                T
                ⁢
                H
              
            
          
        
      
      
        
          
            1
            ,
          
        
        
          
            
              
              
                
                  I
                  X
                
                ⁡
                
                  (
                  k
                  )
                
              
              
            
            >
            
              
                I
                
                  T
                  ⁢
                  H
                
              
              ⁢
              
                
              
              ⁢
              and
              ⁢
              
                
              
              ⁢
              
                
                
                  
                    I
                    Y
                  
                  ⁡
                  
                    (
                    k
                    )
                  
                
                
              
            
            >
            
              I
              
                T
                ⁢
                H
              
            
          
        
      
    
  

for the definition of the current zero zone and the current non-zero zone, considering noise and fluctuations of current, where ITH is a current threshold.