Compact high power alternator

Abstract

An apparatus for converting between mechanical and electrical energy, particularly suited for use as a compact high power alternator for automotive use and “remove and replace” retrofitting of existing vehicles. Various aspects of the invention provide a means of significantly increasing the output of permanent magnet alternators while addressing the issues of radial loading applied to a permanent magnet alternator rotor. Another aspect of the invention allows for the production of power in two discrete voltages. An aspect of this invention allows for a marked increase in output capability without increasing axial length through the use of magnetic fringing. One aspect of the invention offers an effective means of mounting a skewed stack that eliminates or reduces cogging that is present in a permanent magnet machine without negatively impacting airflow. Another aspect of the invention reduces cogging by radially offsetting opposing magnets of a dual rotor permanent magnet machine.

What is claimed is: 
     
         1 . A power conversion apparatus comprising:
 a shaft, a first stator, a second stator, a first rotor and a diametrically opposed second rotor, the shaft, stators, and rotor casings being coaxially disposed with the rotor casings mounted on the shaft, the first and second stators including at least one winding;   the first rotor including a first plurality of permanent magnets disposed proximate to the first stator, separated from the first stator by a predetermined gap distance, such that relative motion of the first stator and first rotor causes magnetic flux from the magnets to magnetically interact with the first stator winding;   the second rotor including a second plurality of permanent magnets disposed proximate to the second stator, separated from the second stator by a predetermined gap distance, such that relative motion of the second rotor and second stator causes magnetic flux from the magnets to magnetically interact with the second stator winding,   wherein the respective permanent first and second plurality of magnets have a predetermined length beyond a predetermined first and second stators individual face lengths;   wherein the apparatus further comprises four lugs that couple the apparatus to a surface;   wherein the disposition of at least one of a first stator slot and a second stator slot and respective permanent magnets is skewed by a predetermined amount relative to the axis of the first and second stator; and   wherein the first rotor and stator pairing and second rotor and stator pairing comprise independent output voltages.   
     
     
         2 . The apparatus of  claim 1  wherein the independent output voltages comprise a direct current and an alternating current. 
     
     
         3 . The apparatus of  claim 2  wherein the first rotor and first stator pairing and second rotor and second stator pairings are configured to provide an output voltage range optimized for 12 VDC and a second independent voltage range optimized for 110 VAC. 
     
     
         4 . The apparatus of  claim 1  wherein the shaft has a predetermined diameter and includes shaft tapered portions disposed between the ends of the shaft at predetermined positions relative to the first and second stators, the diameter of the shaft tapered portions varying in accordance with a predetermined taper from a minimum diameter to a predetermined maximum diameter greater than the shaft predetermined diameter; and
 the first and second rotors include a hub and a central through-bore having the predetermined taper corresponding to a taper of at least one shaft tapered portion of the shaft, the diameter of the tapered through-bore varying in accordance with the predetermined taper from a minimum through-bore diameter greater than the shaft predetermined diameter to a predetermined maximum through-bore diameter; and 
 the first and second rotors hub are disposed with the shaft journaled and extending through the hub through-bore, with the shaft tapered portion received in the through-bore with interior surface of the through bore and exterior surface of the shaft tapered portion in mating contact, wherein cooperation of the tapered first and second rotor bore is in surface contact with the shaft tapered portion positions the first and second rotors both axially and radially with respect to the shaft and first and second stators, coupling the first and second rotors to the shaft for rotation therewith. 
 
     
     
         5 . The apparatus of  claim 1  wherein the first and second rotors and shaft comprise an integral unit. 
     
     
         6 . The apparatus of  claim 1  wherein the shaft is rotatably coupled to a first endplate. 
     
     
         7 . The apparatus of  claim 7  wherein the first and second rotors comprise endcaps coupling a cylindrical casing to the shaft; the casing and endcaps comprising an integral unit.