Patent ID: 11888419
Assignee: JIANGSU UNIVERSITY
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H  Y | IPC H

Claim 3:
4. The unified open-circuit fault-tolerant control method according to claim 1, wherein in step 5), calculating the direct-axis and quadrature-axis fundamental voltages of the VC drive system and the DTC drive system based on the current components id1 and iq1 in the two-phase rotating coordinate system and the predetermined torque Te* comprises:
part 1: obtaining a predetermined quadrature-axis fundamental voltage of the VC drive system;
(1.1) using id=0 control, and inputting a difference between a predetermined direct-axis current zero and a direct-axis current id1 into a proportional integral (PI) controller to obtain a predetermined direct-axis voltage ud1*;
(1.2) obtaining a quadrature-axis current iq1*, and inputting a difference between iq1* and a quadrature-axis current iq1 into the PI controller to obtain a predetermined quadrature-axis voltage uq1*, wherein
the quadrature-axis current iq1* is calculated as follows:, i
   
    q
    ⁢
    1
   
   *
  
  =
  
   
    2
    ⁢
    
     T
     e
     *
    
   
   
    5
    ⁢
    
     p
     r
    
    ⁢
    
     ψ
     f
    
   
  
 

wherein, pr is a number of pole pairs of the motor, and ψf is an amplitude of a permanent magnet flux linkage;
part 2: obtaining a predetermined quadrature-axis fundamental voltage of the DTC drive system;
(2.1) calculating an amplitude, a phase and an estimated torque of a stator flux linkage through the current components id1 and iq1 in the two-phase rotating coordinate system,
wherein, direct-axis and quadrature-axis components of the stator flux linkage are as follows:, {
  
   
    
     
      
       ψ
       d
      
      =
      
       
        
         L
         s
        
        ⁢
        
         i
         
          d
          ⁢
          1
         
        
       
       +
       
        ψ
        f
       
      
     
    
   
   
    
     
      
       ψ
       q
      
      =
      
       
        L
        s
       
       ⁢
       
        i
        
         q
         ⁢
         1
        
       
      
     
    
   
  
 

wherein, Ls is a stator inductance;
obtaining the amplitude and phase of the stator flux linkage from the above equation:, {
  
   
    
     
      
       
        ψ
        s
       
       =
       
        
         
          ψ
          d
          2
         
         +
         
          ψ
          q
          2
         
        
       
      
     
    
    
     
      
       δ
       =
       
        arc
        ⁢
          
        tan
        ⁢
          
        
         (
         
          
           ψ
           d
          
          /
          
           ψ
           q
          
         
         )
        
       
      
     
    
   
   ,
  
 

 and
calculating, based on direct-axis and quadrature-axis inductances of the five-phase permanent magnet fault-tolerant motor that are sub-equal, the estimated torque as follows:, T
   e
  
  =
  
   
    5
    2
   
   ⁢
   
    p
    r
   
   ⁢
   
    ψ
    f
   
   ⁢
   
    i
    
     q
     ⁢
     1
    
   
  
 

(2.2) inputting a difference between the predetermined torque Te* and the calculated torque into a speed PI controller to obtain a torque angle increment Δδ, and obtaining a predetermined value ψs* of the stator flux linkage through a flux linkage adaptive predetermined point control strategy;
rewriting the torque equation by considering that the electromagnetic torque of the five-phase permanent magnet motor is essentially an interaction result of magnetic fields of a rotor and a stator:, T
   e
  
  =
  
   
    
     5
     2
    
    ⁢
    
     p
     r
    
    ⁢
    
     1
     
      L
      s
     
    
    ⁢
    
     
      ψ
      f
     
     ⟶
    
    ×
    
     
      ψ
      s
     
     ⟶
    
   
   =
   
    
     5
     2
    
    ⁢
    
     p
     r
    
    ⁢
    
     1
     
      L
      s
     
    
    ⁢
    
     ψ
     f
    
    ×
    
     ψ
     s
    
    ⁢
      
    sin
    ⁢
      
    δ
   
  
 

wherein, {right arrow over (ψf)} is a magnetic field vector of the rotor; {right arrow over (ψs)} is a magnetic field vector of the stator; and δ is an angle between the stator flux linkage and the rotor flux linkage being a phase angle of the stator flux linkage;
taking the derivative of both sides of the above equation to obtain:, Δ
   ⁢
   
    T
    e
   
  
  =
  
   
    3
    2
   
   ⁢
   
    p
    r
   
   ⁢
   
    1
    
     L
     s
    
   
   ⁢
   
    ψ
    f
   
   ⁢
   
    ψ
    s
   
   ⁢
   Δδ
   ⁢
     
   cos
   ⁢
     
   δ
  
 

wherein, a torque deviation ΔTe and the torque angle increment Δδ have a nonlinear relationship; and the torque angle increment Δδ is obtained by inputting ΔTe into the PI controller;
if the predetermined stator flux linkage is a fixed value, when the motor is operating with no load or sudden load, an additional direct-axis current component is needed to maintain the stator flux linkage unchanged; by inputting the difference between the direct-axis current id1 and zero into the PI controller to obtain the predetermined stator flux linkage, the predetermined stator flux linkage is adaptively adjustable based on the load to ensure that the direct-axis current component is zero when the motor is operating under different conditions;
(2.3) calculating the amplitude, the phase, the torque angle increment Δδ and the predetermined value ψs* of the stator flux linkage by an expected voltage, and obtaining reference values of the direct-axis and quadrature-axis fundamental voltages ud1* and uq1* in the two-phase rotating coordinate system:
expressing the reference values of the direct-axis and quadrature-axis fundamental voltages based on the equations of the direct-axis and quadrature-axis voltages of the five-phase permanent magnet fault-tolerant motor, wherein Rs is a stator resistance:, {
  
   
    
     
      
       
        u
        
         d
         ⁢
         1
        
        *
       
       =
       
        
         
          R
          s
         
         ⁢
         
          i
          
           d
           ⁢
           1
          
         
        
        +
        
         
          
           
            ψ
            s
            *
           
           ⁢
             
           cos
           ⁢
             
           
            (
            
             δ
             +
             
              Δ
              ⁢
              δ
             
            
            )
           
          
          -
          
           
            ψ
            s
           
           ⁢
             
           cos
           ⁢
             
           δ
          
         
         
          Δ
          ⁢
          T
         
        
       
      
     
    
    
     
      
       
        u
        
         q
         ⁢
         1
        
        *
       
       =
       
        
         
          R
          s
         
         ⁢
         
          i
          
           q
           ⁢
           1
          
         
        
        +
        
         
          
           
            ψ
            s
            *
           
           ⁢
             
           sin
           ⁢
             
           
            (
            
             δ
             +
             
              Δ
              ⁢
              δ
             
            
            )
           
          
          -
          
           
            ψ
            s
           
           ⁢
             
           sin
           ⁢
             
           δ
          
         
         
          Δ
          ⁢
          T
         
        
       
      
     
    
   
   .