Rotor lamination shaping for minimum core loss in srms

Abstract

An electrical machine rotor includes a flux-conducting portion and a flux-inhibiting portion. The flux-conducting portion is conducive to conveying an electromagnetic flux and has a plurality of salient rotor poles and a portion of back material. The flux-inhibiting portion is less conducive to conveying an electromagnetic flux than the flux-conducting portion and is disposed entirely outside the boundaries of the rotor poles.

What is claimed is: 
     
         1 - 19 . (canceled) 
     
     
         20 . A system that identifies operational phases of an electrical machine, the system comprising:
 a rotor comprising at least one first hole formed therethrough and at least one second hole formed therethrough   a first detector configured to detect the passage of a light beam through the at least one first hole;   a second detector configured to detect the passage of a light beam through the at least one second hole; and   a phase identifying component that identifies the occurrence of a first operational phase of the machine based upon the detection of light passing through the at least one first hole and identifies the occurrence of a second operational phase of the machine based upon the detection of light passing through the at least one second hole, wherein the at least one first hole is formed a first radial distance from a rotational axis of the rotor and the at least one second hole is formed a second radial distance from the rotational axis that is different than the first radial distance.   
     
     
         21 . The system of  claim 20 , wherein the first and second operational phases are periods during which first and second stator windings, respectively, of the electrical machine are configured to be excited with the flow of current. 
     
     
         22 . The system of  claim 20 , wherein the first radial distance is longer than the second radial distance. 
     
     
         23 . The system of  claim 20 , wherein the at least one first hole comprises one of a plurality of circumferentially-spaced first holes, and the at least one second hole comprises one of a plurality of circumferentially-spaced second holes. 
     
     
         24 . The system of  claim 23 , wherein the plurality of first holes are circumferentially offset from the plurality of second holes. 
     
     
         25 . The system of  claim 23 , wherein the plurality of first holes are spaced radially outward from the plurality of second holes. 
     
     
         26 . The system of  claim 23 , wherein the rotor includes a plurality of circumferentially-spaced poles, wherein each first hole of the plurality of first holes is aligned with a rotor pole of the plurality of rotor poles and each second hole of the plurality of second holes is aligned with a space between adjacent rotor poles. 
     
     
         27 . The system of  claim 20 , wherein the rotor includes a plurality of circumferentially-spaced poles, wherein the at least one first hole is aligned with a rotor pole of the plurality of rotor poles and the at least one second hole is aligned with a space between adjacent rotor poles. 
     
     
         28 . The system of  claim 20 , further comprising:
 a first light source configured to emit the light beam through the at least one first hole; and   a second light source configured to emit the light beam through the at least one second hole.   
     
     
         29 . The system of  claim 20 , further comprising a single light source configured to emit the light beams through the at least one first hole and through the at least one second hole. 
     
     
         30 . The system of  claim 20 , wherein light is detected only by the first detector in the first operational phase. 
     
     
         31 . The system of  claim 20 , wherein light is detected only by the second detector in the second operational phase. 
     
     
         32 . A method for identifying operational phases of an electrical machine, the method comprising:
 detecting the passage of a light beam through at least one first hole formed between opposing surfaces of a rotor of the electrical machine;   identifying the occurrence of a first operational phase of the machine based upon the detection of light passing through the at least one first hole;   detecting the passage of a light beam through at least one second hole formed between the opposing surfaces of the rotor; and   identifying the occurrence of a second operational phase of the machine based upon the detection of light passing through the at least one second hole, wherein the at least one first hole is positioned a first radial distance from the rotational axis of the rotor and the at least one second hole is positioned a second radial distance from the rotational axis that is different from the first radial distance.   
     
     
         33 . The method of  claim 32 , wherein the first and second operational phases are periods during which first and second stator windings, respectively, of the electrical machine are configured to be excited with the flow of current. 
     
     
         34 . The method of  claim 32 , further comprising:
 forming the at least one first hole in the rotor at the first radial distance from the rotational axis; and   forming the at least one second hole in the rotor at the second radial distance from the rotational axis that is shorter than the first radial distance.   
     
     
         35 . The method of  claim 34 , wherein forming the at least one first hole and the at least one second hole comprises forming the at least one first hole and the at least one second hole such that the at least one first hole is circumferentially offset from the at least one second hole. 
     
     
         36 . The method of  claim 32 , further comprising:
 aligning the at least one first hole with a rotor pole of a plurality of circumferentially-spaced rotor poles; and   aligning the at least one second hole with a space between adjacent rotor poles.   
     
     
         37 . The method of  claim 32 , further comprising projecting the light beams through the at least one first hole and through the at least one second hole with a single light source. 
     
     
         38 . The method of  claim 32 , further comprising:
 projecting the light beam through the at least one first hole with a first light source; and   projecting the light beam through the at least one second hole with a second light source.   
     
     
         39 . The method of  claim 32 , wherein light is detected only by the first detector in the first operational phase, and light is detected only by the second detector in the second operational phase.