Patent ID: 11959976
Assignee: SOUTH CHINA UNIVERSITY OF TECHNOLOGY
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC G  H  Y | IPC G  H

Claim 3:
4. The DC converter valve state detection method based on temporal features of converter terminal currents according to claim 1, wherein the step S4 comprises:
S41. during normal operation, triggering the valve VT1, the valve VT2, the valve VT3, the valve VT4, the valve VT5, and the valve VT6 of the three-phase to conduct in turn at 60° equal phase intervals, and according to the steps S2 and S3, calculating a time interval of each valve conducting state in normal operation according to the following formula:, t
      
       HVT
       ⁢
       _
       ⁢
       normal
      
     
     =
     
      T
      3
     
    
   
   
    
     (
     7
     )
    
   
  
 

where tHVT_normal is the valve conduction time interval in normal operation, and T is the time interval of a power frequency cycle;
S42. comparing the valve conduction time interval tHVTm calculated in the step S33 with the valve conduction time interval tHVT_normal in normal operation to determine whether each valve conducting state is abnormal according to the following formula:, {
     
      
       
        
         
          
           
            ❘
            "\[LeftBracketingBar]"
           
           
            
             t
             
              HVT
              m
             
            
            -
            
             t
             
              HVT
              ⁢
              _
              ⁢
              normal
             
            
           
           
            ❘
            "\[RightBracketingBar]"
           
          
          ≤
          ε
         
         ;
            
         normal
               
        
       
      
      
       
        
         
          
           
            ❘
            "\[LeftBracketingBar]"
           
           
            
             t
             
              HVT
              m
             
            
            -
            
             t
             
              HVT
              ⁢
              _
              ⁢
              normal
             
            
           
           
            ❘
            "\[RightBracketingBar]"
           
          
          >
          ε
         
         ;
            
         abnormal
        
       
      
     
    
   
   
    
     (
     8
     )
    
   
  
 

where ε represents a sampling measurement error; and
S43. locating an abnormal valve according to an output state from the valve conduction time interval through a range comparator according to the following formula:, CS
      HVTm
     
     =
     
      {
      
       
        
         
          2
          ;
          
           
            
             t
             
              HVT
              m
             
            
            -
            
             t
             
              HVT
              ⁢
              _
              ⁢
              normal
             
            
           
           >
           ε
          
         
        
       
       
        
         
          1
          ;
          
           
            -
            ε
           
           ≤
           
            
             t
             
              HVT
              m
             
            
            -
            
             t
             
              HVT
              ⁢
              _
              ⁢
              normal
             
            
           
           ≤
           ε
          
         
        
       
       
        
         
          0
          ;
          
           
            
             t
             
              HVT
              m
             
            
            -
            
             t
             
              HVT
              ⁢
              _
              ⁢
              normal
             
            
           
           <
           
            -
            ε
           
          
         
        
       
      
     
    
   
   
    
     (
     9
     )
    
   
  
 

where csHVTm represents a valve state signal, 2 represents that the valve conducting state is lengthened, 1 represents that the valve conducting state is normal, and 0 represents that the valve conducting state is shortened.