Electric power converter

Abstract

By reduction in loss and noise of a three-phase reactor on the AC side of an electric power converter, compactness and reduction in weight of the reactor are realized, and countermeasures for heat and noise are reduced, and a specific frequency component is reduced, thus cost reduction and conversion efficiency are improved, and carriers of a controller are prepared in correspondence to the phases of the electric power converter, and moreover a phase difference of each carrier is set properly.

1 . A method of converting electric power between AC power and DC power, comprising the steps: 
 providing a switching device between an AC circuit and at least one DC line of a DC circuit;    providing a reactor having one side connected to said switching device and another side connected to at least one phase of said AC circuit and said another side being further connected to any one of said at least one DC line by at least one capacitor;    providing a plurality of carrier waves having a phase difference among said plurality of carrier waves;    generating a signal as a function of characteristics said plurality of carrier waves; and    converting DC power on said at least one DC line to AC power or converting AC power on said AC circuit to DC power to thereby provide improved conversion efficiency by reduction in energy loss and a reduction in noise from the reactor.    
   
   
       2 . The method according to  claim 1  wherein said at least one DC lines includes two DC lines and said capacitor is connected between said two DC lines.  
   
   
       3 . The method according to  claim 1  wherein said AC circuit has three lines each of said lines being connected by a respective capacitor to said at least one DC line.  
   
   
       4 . The method according to  claim 1  wherein said switching device functions as a Pulse Width Modulation converter.  
   
   
       5 . An apparatus for converting electric power between AC power and DC power, comprising: 
 a switching device connected between an AC circuit and at least one DC line of a DC circuit;    a reactor having one side connected to said switching device and another side connected to at least one phase of said AC circuit and said another side being further connected to any one of said at least one DC line by at least one capacitor;    a carrier source outputting a plurality of carrier waves having a phase difference among said plurality of carrier waves;    signal generator device outputting a signal as a function of characteristics of said plurality of carrier waves, whereby said apparatus provides conversion of DC power on said at least one DC line to AC power or conversion AC power on said AC circuit to DC power to thereby provide improved conversion efficiency by reduction in energy loss and a reduction in noise from the reactor.    
   
   
       6 . The apparatus according to  claim 5 , wherein said at least one DC lines includes two DC lines and said capacitor is connected between said two DC lines.  
   
   
       7 . The apparatus according to  claim 5 , wherein said at least one DC lines includes two DC lines and said capacitor is connected between said two DC lines.  
   
   
       8 . The apparatus according to  claim 5  wherein said switching device is a Pulse Width Modulation converter.  
   
   
       9 . The apparatus according to  claim 5  further including a plurality of signal wave generators respectively associated with each of said carrier waves.  
   
   
       10 . The apparatus according to  claim 9 , further including a plurality of comparators each of said comparators receiving a respective carrier wave and signal wave at its input and outputting an on or off signal to said switching device.