Patent ID: 11971437
Assignee: HYOSUNG HEAVY INDUSTRIES CORPORATION
Field: Measurement (Instruments)
Classification: CPC G  H | IPC G  H

Claim 3:
4. The grid voltage phase detector of claim 1, wherein the first filter and the fourth filter individually have filtering characteristics in accordance with a Laplace's Formula 1 below in coordinates:, G
              PR_C
            
            ⁡
            
              (
              s
              )
            
          
          =
          
            
              k
              ⁢
              
                ω
                c
              
              ⁢
              s
            
            
              
                s
                2
              
              +
              
                k
                ⁢
                
                  ω
                  c
                
                ⁢
                s
              
              +
              
                ω
                2
              
            
          
        
        ;
      
    
    
      
        
          
        
        ⁢
        
          
            [
            Laplace
            ’
          
          ⁢
          s
          ⁢
          
            
          
          ⁢
          Formula
          ⁢
          
            
          
          ⁢
          1
        
        ]
      
    
  

the second filter has filtering characteristics in accordance with a Laplace's Formula 2 in coordinates:, G
              PR_SN
            
            ⁡
            
              (
              s
              )
            
          
          =
          
            
              
                -
                k
              
              ⁢
              
                
              
              ⁢
              
                ω
                c
              
              ⁢
              ω
            
            
              
                s
                2
              
              +
              
                k
                ⁢
                
                  ω
                  c
                
                ⁢
                s
              
              +
              
                ω
                2
              
            
          
        
        ;
      
    
    
      
        
          
            [
            Laplace
            ’
          
          ⁢
          s
          ⁢
          
            
          
          ⁢
          Formula
          ⁢
          
            
          
          ⁢
          2
        
        ], and
the third filter filtering characteristics in accordance with a Laplace's Formula 3 in coordinates:, G
            PR_SP
          
          ⁡
          
            (
            s
            )
          
        
        =
        
          
            k
            ⁢
            
              
            
            ⁢
            
              ω
              c
            
            ⁢
            ω
          
          
            
              s
              2
            
            +
            
              k
              ⁢
              
                
              
              ⁢
              
                ω
                c
              
              ⁢
              s
            
            +
            
              ω
              2
            
          
        
      
    
    
      
        
          
        
        ⁢
        
          
            [
            Laplace
            ’
          
          ⁢
          s
          ⁢
          
            
          
          ⁢
          Formula
          ⁢
          
            
          
          ⁢
          3
        
        ]
      
    
  

where in the above three Laplace's Formulas, co is resonance frequency, k is a damping element, and ωc is cutoff frequency.