Abstract:
The present invention relates to an improved electric machine which, when operating in motor mode, produces rotational torque without using alternating magnetic polarity, but rather magnetic flux that utilizes coils arranged in a dipolar manner around an axial plane and independently removable stators.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation-in-part application of U.S. patent application Ser. No. 13/837,141 filed on Mar. 15, 2013. 
     
    
     BACKGROUND 
       [0002]    The present invention is an improvement over various attempts to increase the efficiency of electric machines. Examples of these attempts are set forth below:
       U.S. Pat. No. 6,392,370, Bedini, Device and Method of a Back EMF Permanent Magnet Electromagnetic Motor;   U.S. Pat. No. 7,230,358, Smith, DC Resonance Motor;   U.S. Pat. No. 7,459,822, Johnson, Rotating Electric Machine Having Switched or Variable Reluctance with Flux Transverse to the Axis of Rotation; and   US Patent application 2009/0045690, Kerlin, DC Homopolar Motor/Generator.       
 
         [0007]    Also see the following articles published in IEEE Transactions of Vehicular Technology, Vol. 55, No. 6, November 2006:  Electric Motor Drive Selection Issues for HEV Propulsion Systems: A Comparative Study,  written by: Mounir Zeraoulia, Mohamed El Hachemi Benbouzid, Demba Diallo;  A Design of Axial - gap Switched Reluctance Motor for In - Wheel Direct - Drive EV,  written by: Tohru Shibamoto, Kenji Nakamura, Hiroki Goto and Osamu Ishinokura of the Elec. And Comm. Eng. Dept., Tohoku University: and  Design Procedure for Low Cost, Low Mass, Direct Drive, In - Wheel Motor Drivetrains for Electric and Hybrid Vehicles,  written by: Howard C. Lovatt, Darrell Elton, Laurence Cahill, Duc Hau Huynh, Alex Stumpf, Ambarish Kulkarni, Ajay Kapoor, Mehran Ektesabi, Himani Mazumder, Thomas Dittmar, and Gary White. 
       SUMMARY OF THE INVENTION 
       [0008]    The present invention is an efficient poly gap transverse flux electric machine. It can be embodied in various form factors for use in a variety of applications and requires no magnets. In a presently preferred embodiment of invention, a stator member comprises a plurality of removable stator elements that are concentrically positioned around and spaced apart from the drive shaft of the motor. A rotor member is positioned on each end of the drive shaft parallel to the stator member. In one embodiment, a small fan is mounted on the shaft concentrically within the stator. In another embodiment of the invention, a third rotor member is positioned on the shaft concentrically within the stator elements. 
     
    
     
       DESCRIPTION OF THE FIGURES 
         [0009]      FIG. 1  is a perspective exploded view of the stator housing and a pair of rotors mounted on a drive shaft and having a fan mounted the drive shaft therebetween to cool the stator elements in a basic transverse circumferential flux machine of the present invention; 
           [0010]      FIG. 2  is a perspective view the motor with a stator element depicted as being removed from the transverse circumferential flux machine depicted in  FIG. 1 ; 
           [0011]      FIG. 2   a  is an enlarged view of a stator element removed from stator housing as shown in  FIG. 2 ; 
           [0012]      FIG. 3  is a perspective exploded view of the structure of one of the two end rotors of the motor shown in  FIG. 1 ; 
           [0013]      FIG. 4  is a block diagram of the electrical drive circuits for the assembled motor shown in  FIG. 1 ; and 
           [0014]      FIG. 5  is an exploded perspective view of another embodiment of the machine shown in  FIGS. 1 and 2  in which three separate rotor elements are mounted on the drive shaft and concentrically positioned within the core of the stator elements for concentric rotation therewithin. 
       
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0015]    Referring to  FIG. 1 , an exploded, perspective view of rotor members  10  and  11 , respectively, of motor  30  which is more completely depicted in  FIG. 2 . Each rotor  10  and  11  is mounted to drive shaft  15  at its respective ends. As shown in  FIG. 1 , a small stirring fan  12  is shown mounted between rotors  10  and  11  and within the center of the stator members  25 . A small air circulating stirring fan  12  is used to cool stators members  25  shown in  FIG. 2 . In another embodiment, additional rotor members can be placed on drive shaft  15  as shown in  FIG. 5  where they are located concentrically within and spaced apart from the stator member assembly itself. Rotor members  10  and  11  are spiral wound. The spiral windings or rotors are discs made from a spiral wrap of magnetically permeable tape or strip comprise a plurality of rotor poles  14  are formed on the planar surfaces of the discs by cutting and forming notches  13  between the extending pole faces  14 . 
         [0016]    As shown in  FIG. 1 , cylindrical stator frame  20  comprises a number of stator support openings  21  to support stators members  25  ( FIG. 2 ). The rotor assembly  22  ( FIG. 3 .) comprising rotors  11  is positioned along with similar assembly for rotor  10  within stator frame  20  with shaft  15  extending through opening  17  in end plate  18   b  into which opening bearing assembly  19  ( FIG. 2 ) having bearings  19   a  and  19   b  ( FIG. 1 ) supports drive shaft  15 . A similar end plate  18   a  ( FIG. 2 .) having an opening  17  and bearing assembly  19   a  to support the rotor assembly within stator frame  20 . Bolts  23  secure end plates  18  and  18   a  shown in  FIG. 2  to the stator frame  20  and likewise bolts  24  secure bearing assemblies  19   a  and  19   b  to end plates  18  and  18   a,    FIG. 2 , respectively. 
         [0017]      FIG. 2  is a perspective view of motor  30  of the present invention showing a stator assembly  25  removed from the motor assembly. As can be seen, it is readily possible to remove a stator from the motor for field repair. Stator assembly in the present embodiment comprises twelve removable stators  25  which are mounted to the outside perimeter of openings  21 . The actual number of stators will vary with the application configuration and size of the motor. 
         [0018]    Referring to  FIG. 2A , each removable stator assembly  25  comprises a stack of magnetically permeable laminations  31  and electrically conductive spiral windings  33  wrapped around permeable laminations  31 . The winding  33  are a combination of the main magnetic flux producing windings and a small set flux density monitoring windings not shown. Laminations  31  are mounted to a finned heat sink  34  and retained by a clip  36  preferably using an adhesive. Openings  37  permit bolts, not shown, to affix the individual stators to stator assembly  20 . A pair of lead wires  41  and their associated connectors are connected to main magnetic flux windings  33  of the stator, and form the basis to which the electrical drive necessary to produce magnetic flux within the stator. Leads  42  provide the connection to the flux density monitoring windings embedded within the magnetic flux producing windings  33 . Leads  43  connect embedded temperature monitoring means within stack winding laminations  31 . 
         [0019]    As can be seen from  FIG. 2 , the stators are separate removable items and further, if one of the stators malfunctions, it is possible to continue operating the motor until the motor can be shut down and the faulty stator replaced. Most importantly, the motor continues to operate even if one or more stator cores fail. Such operation may cause the motor to consume more power to deliver the same mechanical output power, or it may operate at a lower mechanical output. Most importantly, the motor does not breakdown abruptly. For example, a three phase motor of the present invention will run continuously with the loss of one or two phases of drive current. Stator drive currents are continuously monitored and automatically adjusted by feedback control system to compensate for any lost drive phases. 
         [0020]    Referring to  FIG. 3 , an exploded view of a rotor  11  is shown. The structure of rotor  11  includes a hub  51  onto which a spiral laminated wound rotor member is placed. Pin  52  is pressed into structural hub  51  and goes through the end lamination tang  53   a  of spiral wound laminated rotor which is constructed from a length of magnetically permeable material such as Hiperco or other highly permeable material and wrapped in a spiral manner. The resulting spiral was machined in order to form a number of salient poles  14  by means of cutting grooves  13  in the material. The number of poles  14  in this embodiment is eight, but any number may formed depending on the requirements of each individually configured machine. Spiral wound rotor is located on drive hub  51  and retaining band  54  is placed around the rotor to ensure integrity of said spirally wound, laminated rotor. Retaining plate  55  is placed over the face of the winding and secured with fasteners  58  to mate with structural hub  51 . The purpose of the retaining plate  55  is to ensure lateral integrity to the winding of the spiral laminations. 
         [0021]    In a preferred embodiment, each of the stator members includes a coil positioned parallel to the axis of rotation of the rotor. This motor also includes a detecting means for detecting the position of the rotor in relationship to the stator members. A control means is provided for receiving at least a first input from the rotor&#39;s rotation detecting means for controlling input into selected stator members in response to the detected signals produced by the detecting means. A control means also includes means for providing a current to at least one stator coil in response to a signal from the detecting means. 
         [0022]    With reference to  FIG. 4 , a block diagram is shown for controlling the motors of the present invention. A primary AC connection  65  is provided to supply mains alternating current to the drive circuitry. The supplied current may be single phase alternating current or poly-phase alternating current depending on the configuration of the motor. Input AC power is rectified into direct current by means of rectifier  66 , and low voltage low power DC power supply  67 . Output of rectifier  66  is then used to power the internal high-power dc bus  70 , while the output of the low-voltage low-power DC power supply  67  is used to power the low-power DC bus  69 . The voltage level of the high-power DC bus  70  is governed by the desired operating parameters and wiring of the motor to be controlled. The low-power DC bus  69  then supplies rated power to the microprocessor control circuit  71 . The microprocessor control circuit  71  provides for overall motor control by applying the appropriate drive signals to pre-driver electronic circuits  72 , and by reconciling the feedback from the motor with the drive signals provided to the pre-driver electronic circuits  72 . This feedback from the motor is (but not limited to) rotor positional feedback  74  as well as actual stator-drive current (via current sensors  75 ), and temperature, vibration, and magnetic-flux level feedback  76 . The microprocessor control circuit  71  is commanded, via the user interface  68 , which accepts controls from the user of the invention. User interface  68 , may be part of the physical control means, may be a part of the physical control means separated by a distance, or may be embodied as a network interface. The output of the pre-driver electronic circuits  72 , then drives the power electronic switching elements in the stator drive electronics  73 . The purpose of the power electronic switching devices in the stator drive electronics  73  is to apply power from the high-power DC bus  70  to the stators of the motor in the proper sequence, with the proper on off time modulation as required by the given embodiment of the present invention. The number of output phases of the stator drive electronics  73  and pre driver electronics  72  are determined by the given configuration of present invention, but must be at least two or more. The output of the stator drive electronics  73  is sent to the stator coils of the motor via drive bus  77 . 
         [0023]    Alternatively the poly gap transverse circumferential flux machine may be configured using primary coils that produce commutation currents from counter-electromotive force (herein referred to as “CEMF”), which when directed through a circuit, such as an LC circuit, enhance the efficiency of the machine. These currents are switched on and off through a secondary set of stator coils without the need for these currents to be returned to the control system&#39;s intermediate DC bus. In another embodiment, an induced current passes within close proximity to the primary coils and directed to a power source and introduced into a set of secondary coils. The machine creates rotational torque as a direct result of rotor members being attracted to both primary and secondary stator members before commutation and repelled away from the stator coils as a consequence of the commutation event. 
         [0024]    Referring to  FIG. 5 , motor  79  of the present invention is shown. Motor  79  is similar in construction to motor  30 , but includes a centrally located rotor  80  mounted to shaft  85  concentrically with stator  90 . Centrally positioned rotor  79  comprises a solid or laminated body having polar lobes  81   a  and  81   b  formed by annular groove  82  circumferentially around the assembly. A pair of secondary rotor plates  83  and  84  are secured to each opposing end of central rotor  80  and onto shaft  85 . As shown in this embodiment, six modular, replaceable stators  90  are positioned circumferentially around a central rotor  80 , between end plates  91 ,  92 . along with two external rotors  83 ,  84 . Each stator  90  is comprised of a highly permeable core material, such as stacked laminated electrical steel. Additionally, two pole pieces  94 ,  95  are shaped to mirror face areas of each rotor pole are fixed onto each end of each stator core and held into position by fixing bolt  114 , first passing through end plate  91 , then through first pole piece  95 , through said core, then through opposing pole piece  94 , then into opposing end plate  92 . Fixing bolts  87  pass through end plate  91  then completely through tie block  112  and fixed into opposing end plate  92 ; thus securing the entire motor as an assembly  79 . The embodiment of  FIG. 5  provides enhanced power with control and discloses a number of possible configurations that can be utilized. The configuration shown in  FIG. 5  provides stators  90  are juxta-positioned around rotors  80 ,  83  and  84  which are concentrically mounted. The embodiment shown in  FIG. 5  provides the advantages of the motor described and shown in the inventors&#39; motor disclosed in U.S. patent application Ser. No. 13/397,121, of which this application is a continuation in part. 
         [0025]    While presently preferred embodiments of the invention have been shown and described, it may otherwise be embodied within the scope of the claims. As is customary, it will be understood that no limitation of the scope of the invention is thereby intended. The invention encompasses such alterations and further modifications in the illustrated apparatus, and such further applications of the principles of the invention illustrated herein, as would normally occur to persons skilled in the art to which the invention relates.