Patent ID: 11870335
Assignee: BEIJING INSTITUTE OF TECHNOLOGY
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H  Y | IPC H

Claim 1:
2. The WPT system regulation method for implementing ZVS in a wide power range according to claim 1, wherein the determining, according to a topology structure of a WPT system and based on a linear state equation, a phase-shift angle boundary and a switching frequency boundary of an inverter that meet ZVS specifically comprises:
constructing a linear state equation, wherein the linear state equation is {dot over (x)}(t)=Ax(t)+Bu(t) , wherein {dot over (x)}(t) is a derivative of a state quantity x(t), x(t)=[iLf1(t) uCf1(t) i1(t) uC1(t)]T, wherein iLf1(t) is a current through an inductor in a primary-side resonance compensation network, uCf1(t) is a voltage at both ends of a parallel capacitor in the primary-side resonance compensation network, i1(t) is a current through a self-inductor of a transmit coil, and uC1(t) is a voltage at both ends of a series capacitor in the primary-side resonance compensation network, wherein A is a system matrix and, A
   =
   
    [
    
     
      
       0
      
      
       
        -
        
         1
         
          L
          
           f
           ⁢
           1
          
         
        
       
      
      
       0
      
      
       0
      
     
     
      
       
        1
        
         C
         
          f
          ⁢
          1
         
        
       
      
      
       0
      
      
       
        -
        
         1
         
          C
          
           f
           ⁢
           1
          
         
        
       
      
      
       0
      
     
     
      
       0
      
      
       
        1
        
         
          L
          1
         
         +
         
          L
          req
         
        
       
      
      
       
        -
        
         
          Re
          ⁡
          (
          
           Z
           ref
          
          )
         
         
          
           L
           1
          
          +
          
           L
           req
          
         
        
       
      
      
       
        -
        
         1
         
          
           L
           1
          
          +
          
           L
           req
          
         
        
       
      
     
     
      
       0
      
      
       0
      
      
       
        1
        
         C
         1
        
       
      
      
       0
      
     
    
    ]
   
  
  ,, wherein Cf1 is the parallel capacitor in the primary-side resonance compensation network, Lf1 is the inductor in the primary-side resonance compensation network, L1 is the self-inductor of the transmit coil, Lreq is an equivalent inductor, C1 is the series capacitor in the primary-side resonance compensation network, Re(Zref) is a real part of an impedance Zref mapped from a secondary side to a primary side, and Re(Zref) is related to a switching frequency, wherein B is a control matrix and, B
   =
   
    
     [
     
      
       
        
         1
         
          L
          
           f
           ⁢
           1
          
         
        
       
       
        0
       
       
        0
       
       
        0
       
      
     
     ]
    
    T
   
  
  ;, and u(Δ) is an output voltage of a primary-side inverter, u(Δ0)=Udc, u(Δ1)=0, u(Δ2)=−Udc, and u(Δ3)=0, where Udc is a primary -side DC input voltage, Δ0 represents a time period t0˜t1, Δ1 represents a time period t1˜t2, Δ2 represents a time period t2˜t3, and Δ3 represents a time period t3˜t4, where Δ0, Δ1, Δ2, and Δ3 are related to phase-shift angles;
solving the linear state equation by using a numerical method and a formula, [
    
     
      
       
        -
        
         e
         
          A
          ⁢
          
           Δ
           0
          
         
        
       
      
      
       I
      
      
       0
      
      
       0
      
     
     
      
       0
      
      
       
        -
        
         e
         
          A
          ⁢
          
           Δ
           1
          
         
        
       
      
      
       I
      
      
       0
      
     
     
      
       0
      
      
       0
      
      
       
        -
        
         e
         
          A
          ⁢
          
           Δ
           2
          
         
        
       
      
      
       I
      
     
     
      
       I
      
      
       0
      
      
       0
      
      
       
        -
        
         e
         
          A
          ⁢
          
           Δ
           3
          
         
        
       
      
     
    
    ]
   
   [
   
    
     
      
       x
       ⁡
       (
       
        t
        0
       
       )
      
     
    
    
     
      
       x
       ⁡
       (
       
        t
        1
       
       )
      
     
    
    
     
      
       x
       ⁡
       (
       
        t
        2
       
       )
      
     
    
    
     
      
       x
       ⁡
       (
       
        t
        3
       
       )
      
     
    
   
   ]
  
  =
  
   [
   
    
     
      
       
        
         A
         
          -
          1
         
        
        (
        
         
          e
          
           A
           ⁢
           
            Δ
            0
           
          
         
         -
         I
        
        )
       
       ⁢
       
        BU
        dc
       
      
     
    
    
     
      0
     
    
    
     
      
       
        -
        
         
          A
          
           -
           1
          
         
         (
         
          
           e
           
            A
            ⁢
            
             Δ
             2
            
           
          
          -
          I
         
         )
        
       
       ⁢
       
        BU
        dc
       
      
     
    
    
     
      0
     
    
   
   ], according to a symmetry of waveforms of an output voltage and an output current of an inverter in a steady state, to obtain a state quantity at each switching moment, wherein the switching moments comprise a moment t0, a moment t1, a moment t2, and a moment t3, wherein x(t0) is a state quantity at the moment t0, x(t1) is a state quantity at the moment t1, x(t2) is a state quantity at the moment t2, and x(t3) is a state quantity at the moment t3; and
determining a phase-shift angle boundary and a switching frequency boundary of an inverter according to a condition for meeting ZVS, wherein the condition for meeting ZVS is, {
   
    
     
      
       
        
         i
         
          L
          ⁢
          f
          ⁢
          1
         
        
        (
        
         t
         0
        
        )
       
       <
       0
      
     
    
    
     
      
       
        
         i
         
          L
          ⁢
          f
          ⁢
          1
         
        
        (
        
         t
         1
        
        )
       
       >
       0
      
     
    
    
     
      
       
        
         i
         
          L
          ⁢
          f
          ⁢
          1
         
        
        (
        
         t
         2
        
        )
       
       >
       0
      
     
    
    
     
      
       
        
         i
         
          L
          ⁢
          f
          ⁢
          1
         
        
        (
        
         t
         3
        
        )
       
       <
       0
      
     
    
   
  
    
  ,, namely, iLf1_min=min{−iLf1(t0), iLf1(t1), iLf1(t2), −iLf1(t3)}>0, where iLf1_min is a minimum absolute value of a current of the inductor in the primary-side resonance compensation network, iLf1(t0) is a current through the inductor in the primary-side resonance compensation network at the moment t0, iLf1(t1) is a current through the inductor in the primary-side resonance compensation network at the moment t1, iLf1(t2) is a current through the inductor in the primary-side resonance compensation network at the moment t2, and iLf1(t3) is a current through the inductor in the primary -side resonance compensation network at the moment t3.