Patent ID: 11967909
Assignee: DAIKIN INDUSTRIES, LTD.
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. A power conversion device comprising:
a voltage source that converts a single-phase alternating current voltage Vin and outputs a rectified voltage;
a first switch having one end connected to an output end of the voltage source, the first switch becoming electrically conductive in accordance with a predetermined first duty drec;
a second switch having one end connected to an other end of the first switch, the second switch becoming electrically conductive in accordance with a predetermined second duty dc;
a capacitor having one end connected to an other end of the second switch and an other end connected to a common end of the voltage source;
a clamp diode connected in parallel with the second switch;
a third switch having a first end connected to the other end of the first switch, a second end connected to the common end of the voltage source, and a third end selectively electrically connected to the first end or the second end of the third switch, the third end electrically connected to the first end in accordance with a predetermined third duty dz;
a current source having one end connected to the other end of the first switch and an other end connected to the third end of the third switch;
a reactor having one end connected to the output end of the voltage source;
a diode having an anode connected to an other end of the reactor and a cathode connected between the second switch and the capacitor; and
a fourth switch having one end connected to the anode of the diode, and an other end connected to the common end of the voltage source, the fourth switch becoming electrically conductive in accordance with a predetermined fourth duty dl,
the third switch and the current source forming a 3n-phase voltage shape inverter where n is a positive integer,
the power conversion device being configured such that
in a first duration where an instantaneous value of the voltage source is higher than a direct current voltage command value Vdc*, the second switch is turned off, the predetermined first duty drec and the predetermined third duty dz are selected so that a direct current voltage Vdc to be input to the current source becomes equal to the direct current voltage command value Vdc*, a first conversion operation of supplying power from the voltage source to the current source is performed, and the capacitor is charged by the rectified voltage via the clamp diode, and
in a second duration where the instantaneous value of the voltage source is equal to or less than the direct current voltage command value Vdc*, the first switch is turned off, the predetermined second duty dc and the predetermined third duty dz are selected so that the direct current voltage Vdc to be input to the current source becomes equal to the direct current voltage command value Vdc*, and a second conversion operation of supplying power from the capacitor to the current source is performed,

the predetermined first duty drec, the predetermined second duty dc, and the predetermined third duty dz satisfy

drec+dc+dz=1

and
when a maximum value of the single-phase alternating current voltage Vin is Vm, an angular velocity of the single-phase alternating current voltage Vin is ω, and time is t,
the predetermined first duty drec and the predetermined second duty dc in a period of the first conversion operation are expressed by, d
      rec
    
    =
    
      
        
          V
          dc
        
        *
      
      
        
          V
          m
        
        ⁢
        
          
          
            sin
            ⁡
            
              (
              
                ω
                ⁢
                
                  
                
                ⁢
                t
              
              )
            
          
          
        
      
    
  

  
    
      
        d
        c
      
      =
      0
    
    ,
  

the predetermined first duty drec and the predetermined second duty dc in a period of the second conversion operation are expressed by, d
      rec
    
    =
    0
  

  
    
      
        d
        c
      
      =
      
        
          
            V
            dc
          
          *
        
        
          V
          m
        
      
    
    ,
  

and
a boundary phase angle φ between the first duration and the second duration is expressed by, ∅
  =
  
    
      
        sin
        
          -
          1
        
      
      ⁡
      
        (
        
          
            
              V
              dc
            
            *
          
          
            V
            m
          
        
        )
      
    
    .