Alternating current generator having a plurality of independent three-phase windings

Abstract

There is provided an alternating current generator comprising: a rotatably supported field rotor having a pair of opposed rotor pole cores, each being provided with P/2 claw poles wherein P is an even number, and a field winding wound on the rotor pole cores; an armature core located around the outer periphery of the field rotor and having axially extending 3nP slots wherein n is an integer more than one; n independent sets of three-phase windings, each being wound on the armature core by being inserted in the slots so that the n sets of three-phase windings are shifted from each other by electrical angle of π/(3n) radians; and three-phase rectifiers connected with the n sets of three-phase windings to rectify output voltages generated by the three-phase windings.

We claim:  
     
       1. An alternating current generator comprising a rotatably supported field rotor having a pair of opposed rotor pole cores, each being provided with P/2 claw poles wherein P is an even number; 
       an armature core located around the outer periphery of the field rotor and having axially extending 3nP slots wherein n is an integer more than one;  
       n independent sets of three-phase windings, each being wound on the armature core by being inserted in the slots so that the n sets of three-phase windings are shifted from each other by an electrical angle of π/(3n) radians; and  
       three-phase rectifiers connected with the n sets of three-phase windings to rectify output voltages generated by the three-phase windings.  
     
     
       2. An alternating current generator as set forth in  claim 1 , in which said claw poles have a trapezoidal peripheral shape and P=12 and n=2 hold so that said armature core has 72 slots and said three-phase windings include first and second three-phase windings. 
     
     
       3. An alternating current generator as set forth in  claim 2 , in which the length L of the base side of the trapezoidal peripheral shape of said claw poles is less than 7τ-A, wherein τdenotes a slot pitch of said armature core and A denotes the peripheral width of a tip end of a tooth portion of said armature core. 
     
     
       4. An alternating current generator as set forth in  claim 2 , in which said first and second three-phase windings are substantially identical with each other in diameter of the cross-section of a winding conductor, the number of parallel winding conductors, and the number of winding turns. 
     
     
       5. An alternating current generator as set forth in  claim 2 , in which said first and second three-phase windings of each phase are wave-shaped windings having a plural number of parallel winding conductors. 
     
     
       6. An alternating current generator as set forth in  claim 1 , in which all the n sets of three-phase windings are connected in Y-form, respectively, and each set of three-phase windings has an independent three-phase rectifier connected thereto, and direct current output terminals of the respective rectifiers are connected in parallel with each other. 
     
     
       7. An alternating current generator as set forth in  claim 2 , in which all the n sets of three-phase windings are connected in Y-form, respectively, and each set of three-phase windings has an independent three-phase rectifier connected thereto, and direct current output terminals of the respective rectifiers are connected in parallel with each other. 
     
     
       8. An alternating current generator as set forth in  claim 1 , in which the n sets of three-phase windings are two sets of three-phase windings, with one set being connected in Y-form and the other set being connected in delta-form, and the two sets of three-phase windings are connected in parallel with each other and then connected to a common three-phase rectifier. 
     
     
       9. An alternating current generator as set forth in  claim 2 , in which the n sets of three-phase windings are two sets of three-phase windings, with one set being connected in Y-form and the other set being connected in delta-form, and the two sets of three-phase windings are connected in parallel with each other and then connected to a common three-phase rectifier. 
     
     
       10. An alternating current generator as set forth in  claim 8 , in which the number of turns of the delta-connected thee-phase windings is 1.5 to 2.5 times as many as that of the Y-connected three-phase windings. 
     
     
       11. An alternating current generator as set forth in  claim 9 , in which the number of turns of the delta-connected three-phase windings is 1.5 to 2.5 times as many as that of the Y-connected three-phase windings. 
     
     
       12. An alternating current generator as set forth in  claim 2 , in which said first and second three-phase windings are inserted in odd and even numbered slots of said armature core, respectively, and center portions of respective coil ends of each phase of said first and second three-phase windings projecting from both sides of said armature core are arranged with a pitch pattern of 1, 2, 2, 3, 2, 2 times as large as a unit pitch in a peripheral direction of said armature core. 
     
     
       13. An alternating current generator comprising: 
       a frame for defining an accommodation space therein;  
       a substantially cylindrical armature core rigidly supported in the accommodation space of said frame and having a plurality of slots axially extending along an inner wall thereof;  
       first and second sets of three-phase windings wound respectively being inserted in said plurality of slots so that the respective sets of three-phase windings are arranged with a phase difference of electrical angle of π/6 radians therebetween;  
       a field rotor comprising: a field core having a pair of opposed rotor pole cores and rotatably disposed inside and armature core, each of said rotor pole cores having P/2 claw poles wherein P is an even number; and a field winding wound around said rotor pole cores; and  
       three-phase rectifiers connected with said first and second sets of three-phase windings for rectifying an output generated therefrom,  
       said claw poles having a substantially trapezoidal peripheral shape, and said armature core having 6P slots.  
     
     
       14. An alternating current generator as set forth in  claim 13 , in which the length L of the base side of the trapezoidal peripheral shape of said claw poles is less than 7π-A, wherein π denotes a slot pitch of said armature core and A denotes the peripheral width of a tip end of a tooth portion of said armature core. 
     
     
       15. An alternating current generator as set forth in  claim 13 , in which both said first and second sets of three-phase windings are connected in Y-form, respectively, and each set of three-phase windings has an independent three-phase rectifier connected thereto, and direct current output terminals of the respective rectifiers are connected in parallel with each other. 
     
     
       16. An alternating current generator as set forth in  claim 14 , in which both said first and second sets of three-phase windings are connected in Y-form, respectively, and each set of three-phase windings has an independent three-phase rectifier connected thereto, and direct current output terminals of the respective rectifiers are connected in parallel with each other. 
     
     
       17. An alternating current generator as set forth in  claim 13 , in which one set of three-phase windings is connected in Y-form and the other set being connected in delta-form, and the two sets of three-phase windings are connected in parallel with each other and then connected to a common three-phase rectifier. 
     
     
       18. An alternating current generator as set forth in  claim 14 , in which one set of three-phase windings is connected in Y-form and the other set being connected in delta-form, and the two sets of three-phase windings are connected in parallel with each other and then connected to a common three-phase rectifier. 
     
     
       19. An alternating current generator as set forth in  claim 17 , in which the number of turns of the delta-connected three-phase windings is 1.5 to 2.5 times as many as that of the Y-connected three-phase windings. 
     
     
       20. An alternating current generator as set forth in  claim 18 , in which the number of turns of the delta-connected three-phase windings is 1.5 to 2.5 time as many as that of the Y-connected three-phase windings. 
     
     
       21. An alternating current as set forth in  claim 13 , in which said first and second sets of three-phase windings are inserted in odd and even numbered slots of said armature core, respectively, and center portions of respective coil ends of each phase of said first and second three-phase windings projecting from both sides of said armature core are arranged with a pitch pattern of 1, 2, 2, 3, 2, 2 times as large as a unit pitch in a peripheral direction of said armature core. 
     
     
       22. The alternating current generator as claimed in  claim 1 , wherein the alternating current generator is an alternating current generator for a vehicle.  
     
     
       23. The alternating current generator as claimed in  claim 22 , wherein the alternating current generator for a vehicle is adaptive to be driven by an engine of a vehicle, and wherein the field rotor, the armature core, the three- phase windings and the three - phase rectifiers are adaptive to supply electric power to a vehicle battery and a vehicle load.    
     
     
       24. The alternating current generator as claimed in  claim 23 , wherein the field rotor has a field winding, and wherein the alternating current generator comprises a voltage regulator which preforms conduction control of the field winding in response to the terminal voltage of the vehicle battery to regulate the vehicle battery at a constant terminal voltage.  
     
     
       25. The alternating current generator as claimed in  claim 1 , wherein each of said claw poles has a trapezoidal peripheral shape, and only one tooth portion of said armature core may simultaneously overlap with two of said claw poles.  
     
     
       26. The alternating current generator as claimed in  claim 13 , wherein the alternating current generator is an alternating current generator for a vehicle.  
     
     
       27. The alternating current generator as claimed in  claim 26 , wherein the alternating current generator for a vehicle is adaptive to be driven by an engine of a vehicle, and wherein the field rotor, the armature core, the three- phase windings and the three - phase rectifiers are adaptive to supply electric power to a vehicle pattern and a vehicle load.    
     
     
       28. The alternating current generator as claimed in  claim 27 , wherein the field rotor has a field winding, and wherein the alternating current generator comprises a voltage regulator which performs conduction control of the field winding in response to the terminal voltage of the vehicle battery to regulate the vehicle battery at a constant terminal voltage.  
     
     
       29. The alternating current generator as claimed in  claim 13 , wherein each of said claw poles has a trapezoidal peripheral shape, and only one tooth portion of said armature core may simultaneously overlap with two of said claw poles.