Abstract:
An object of the invention is to provide a transverse flux machine apparatus (TFMA) with simple and economical core structure. The TFMA employs a core having laminated iron plates. The core has left diagonal portions and right diagonal portions for forming the 3D flux passages. A plurality of the 3D structures employs laminated iron cores with diagonal portions. By means of employing the diagonal portions, the core looks like a centipede. The centipede-like TFM called CTFM can have a plurality of types. A plurality of motor structure and a plurality of driving means are proposed for the CTFM.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims benefit under 35 U.S.C.119 of JP2012-048906 filed on Mar. 6, 2012, the title of TRANSVERSE FLUX MACHINE APPARATUS, JP2012-090672 filed on Apr. 12, 2012, the title of TRANSVERSE FLUX MACHINE APPARATUS and JP2012-95235 filed on Apr. 19, 2012, the title of TRANSVERSE FLUX MACHINE APPARATUS, the entire content of which is incorporated herein reference. 
       BACKGROUND OF INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a transverse flux machine apparatus (TFMA). More particularly, this invention relates to a transverse flux machine apparatus having a core formed with laminated iron plates. 
         [0004]    2. Description of the Related Art 
         [0005]    A transverse flux machine (TFM) with a large number of poles and short current passages is an attractive electric machine because the machine has a high torque/weight ratio, a high power/weight ratio and a low copper loss. U.S. Pat. No. 7,830,057 proposes a tandem transverse flux machine (TFM) shown in  FIG. 1 . The TFM is constructed with many core segments. However, the segmented core structure causes to increase magnetic resistance and to decrease robustness. 
         [0006]      FIG. 2  shows another prior TFM employing a core made from soft magnetic composites (SMC). However, magnetic characteristic and robustness of the SMC core are not enough. An electric vehicle and a wind turbine wait a direct-drive machine capable of reducing a gear loss and an inertial mass strongly. However, prior TFMs having a permanent magnet rotor is not desirable for a variable-speed machine because of the high electromotive force (EMF) in a high-speed zone and a cost of the permanent magnets. The other proposed TFM such as a TFSRM has smaller values of torque/weight ratio and other problems. 
       CITATION LIST 
     Patent Literature 
       [0007]    PTL 1:U.S. Pat. No. 7,830,057 
       SUMMARY OF INVENTION  
       [0008]    An object of the invention is to provide a transverse flux machine apparatus (TFMA) having simple core structure employing laminated iron plates. Another object of the invention is to provide a transverse flux machine apparatus having a reduced power loss. Another object of the invention is to provide a transverse flux machine apparatus having an excellent torque characteristic for a variable-speed application. 
         [0009]    As for a first aspect of the invention, a transverse flux machine (TFM) has a laminated core made of laminating iron plates with diagonal portions. The diagonal portions for connecting a yoke portion and teeth magnetically are made by means of bending the iron plates. The core has the left teeth, the right teeth, the left diagonal portions, the right diagonal portions and the yoke portion. The centipede-like TFM of the present invention is called CTFM because the core with the diagonal portions seems like a centipede. It is desirable that the diagonal portions extending diagonally extend straightly. It is desirable that an angle between the diagonal portions and the teeth is in a range from 25 degrees to 65 degrees. 
         [0010]    However, it is not easy for the TFMs including the CTFM, the centipede-like TFM, to compete with conventional radial flux machines (RFMs) because the RFMs have a long history of the developing. The TFM cannot use the developed results of the RFMs straightly because single-phase rotation method and the core structure of the TFMs are different from popular three-phase RFMs. Accordingly, it is desirable to develop the peculiar motor structure and the peculiar driving converter in order to use features of the TFM fully. Therefore, unique motor structures have been further developed for the TFM as below. 
         [0011]    First, a transverse flux induction machine (TFIM) of squirrel cage type is disclosed. The diagonal portions of a rotor of the CTFM, centipede-like TFM, is attracted via rotor teeth by stator teeth to the radial direction of the rotor. Accordingly, it is preferable for the CTFM to employ supporting members supporting at least one of the rotor teeth and the rotor diagonal portions. According to the transverse flux induction machine (TFIM) of the invention, the supporting member is capable of performing as a well-known squirrel-cage secondary conductor with a very low electric resistance because the supporting member made of aluminum or copper surrounds the rotor teeth. Further, the electric-resistance value of the secondary conductor of the TFM becomes low because the TFM has many spaces having the large cross-section and the short length. Thus, a secondary copper loss of the TFIM is reduced largely. 
         [0012]    But, it is difficult for the TFIM to generate a starting torque because the TFIM is essentially the single-phase induction machine. The above problem is solved by means of using the double salient structure of the TFIM. In other words, the TFIM of the present invention is started as a single-phase synchronous reluctance motor or a single-phase switched reluctance motor. 
         [0013]    According to a preferred embodiment, a first tandem TFIM driven by an internal combustion engine is connected to a second tandem TFIM for driving wheels of a vehicle via a relay. The relay is opened after when generating currents of the first tandem TFIM become nearly equal to motor currents of the second tandem TFIM. 
         [0014]    Next, a transverse flux wound rotor machine (TFWRM) for generating a magnet torque of a single-phase synchronous motor is proposed. The TFWRM has a field winding extending in a space between the left teeth and the right teeth. Furthermore, three TFWRMs arranged in tandem have three secondary windings and a three-phase full-bridge diode rectifier fixed to the rotor. The rectifier supplies a field current to the field windings after rectifying the three-phase secondary voltage induced across the three secondary windings. The field winding has a low electric resistance because the field winding has a short length. Thus, a copper loss of the field winding is reduced. 
         [0015]    According to a preferred embodiment,each of trapezoid currents or each alternative current with a frequency being different from a fundamental component (a primary component) is supplied to each single-phase winding wound on each stator core. Harmonics of the magnet motive force excited by the stator current induce the secondary alternative voltage across each secondary winding. 
         [0016]    According to a preferred embodiment, each primary field winding is wound on each stator core of TFWRMs arranged in tandem. A DC primary field current is supplied to the primary field windings connected in series. Thus, the primary field winding supplies the field current to the field winding of the rotor effectively, when the TFWRM is rotated. 
         [0017]    Next, a transverse flux switched reluctance machine (TFSRM) for generating a torque of a single-phase switched reluctance motor is proposed. Further, a transverse flux permanent magnet switched reluctance machine (TFPMSRM) capable of generating a magnet torque and the reluctance torque simultaneously is proposed. The volume of the TFPMSRM is not increased by means of adding the permanent magnet because the TFSRM has the large space. Further,a plurality of the TFMs arranged axially or circumstantially in tandem is proposed. The other features and the other advantages of the invention are explained in embodiments. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0018]      FIG. 1  is an axial cross-section showing prior TFMs with segmented cores. 
           [0019]      FIG. 2  is a schematic cross-section showing a prior TFM with a SMC core. 
           [0020]      FIG. 3  is an axial cross-section showing three TFIMs (transverse flux induction machines) arranged in tandem. 
           [0021]      FIG. 4  is an axial cross-section an axially laminated stator core shown in  FIG. 3 . 
           [0022]      FIG. 5  is a partial side view showing the stator core shown in  FIG. 4 . 
           [0023]      FIG. 6  is a partial plan view of the stator core shown in  FIG. 4 . 
           [0024]      FIG. 7  is a circumferential development showing an arrangement of rotor teeth shown in  FIG. 3 . 
           [0025]      FIG. 8  is a circumferential development showing an arrangement of stator teeth shown in  FIG. 3 . 
           [0026]      FIG. 9  is a block circuit configuration showing a TFMA for driving the TFIMs shown in  FIGS. 3 . 
           [0027]      FIG. 10  is a flow chart showing the connection-changing operation of TFMA shown in  FIG. 9 . 
           [0028]      FIG. 11  is a schematic configuration showing an electric power system of series-hybrid vehicle car with two motor-generators employing the TFIMs shown in  FIG. 3 . 
           [0029]      FIG. 12  shows frequencies of a common frequency of the two motor-generators and two rotor frequencies being equivalent to rotor speeds of two motor-generators shown in  FIG. 11 . 
           [0030]      FIG. 13  is a flow-chart showing connection-changing operation of the electric power system shown in  FIG. 11 . 
           [0031]      FIG. 14  is an axial cross-section showing three TFWRMs (transverse flux wound-rotor machines) arranged in tandem. 
           [0032]      FIG. 15  is a circuit topology configuration showing an rotor circuit for supplying a field current to field windings of the TFWRM shown in  FIG. 14 . 
           [0033]      FIG. 16  is a circuit topology configuration showing an three-phase inverter for supplying a three-phase stator current to three single-phase windings. 
           [0034]      FIG. 17  is a vector view for showing a fundamental current component and a high frequency current component. 
           [0035]      FIG. 18  is a figure showing one wave pattern example of a phase current employed by the TFWRM shown in  FIG. 14 . 
           [0036]      FIG. 19  is a flow-chart showing a torque control of the TFWRM shown in  FIG. 14 . 
           [0037]      FIG. 20  is a circumferential development showing arrangement of rotor teeth shown in  FIG. 14 . 
           [0038]      FIG. 21  is a circumferential development showing arrangement of stator teeth shown in  FIG. 14 . 
           [0039]      FIG. 22  is a circumferential development showing a first position of the rotor teeth shown in  FIG. 14 . 
           [0040]      FIG. 23  is a circumferential development showing a second position of the rotor teeth shown in  FIG. 14 . 
           [0041]      FIG. 24  is a circumferential development showing a third position of the rotor teeth shown in  FIG. 14 . 
           [0042]      FIG. 25  is a circumferential development showing a fourth position of the rotor teeth shown in  FIG. 14 . 
           [0043]      FIG. 26  is an axial cross-section showing another TFWRMs arranged in tandem. 
           [0044]      FIG. 27  is a circuit topology configuration showing a field current circuit of the TFWRMs shown in  FIG. 26 . 
           [0045]      FIG. 28  is an axial cross-section showing three TFPMs arranged in tandem. 
           [0046]      FIG. 29  is a partial development showing the pole areas of a permanent magnet rotor shown in  FIG. 28 . 
           [0047]      FIG. 30  is a partial development showing the stator teeth shown in  FIG. 28 . 
           [0048]      FIG. 31  is a partial development showing a first magnetizing process of the permanent magnet rotor shown in  FIG. 28 . 
           [0049]      FIG. 32  is a partial development showing a second magnetizing process of the permanent magnet rotor shown in  FIG. 28 . 
           [0050]      FIG. 33  is an axial cross-section showing another three TFPM arranged in tandem. 
           [0051]      FIG. 34  is a circumferential development showing an arrangement of rotor pole areas shown in  FIG. 33 . 
           [0052]      FIG. 35  is a schematic axial cross-section showing a separated left core, a separated common core and a separated right core of a stator shown in  FIG. 33 . 
           [0053]      FIG. 36  is a circumferential development showing an arrangement of stator teeth shown in  FIG. 33 . 
           [0054]      FIG. 37  is a circumferential development showing an arrangement of yoke portions of stator core shown in  FIG. 33 . 
           [0055]      FIG. 38  is an axial cross-section of another transverse flux permanent magnet machine (TFPM). 
           [0056]      FIG. 39  is an axial cross-section of separated stator cores of the TFPM shown in  FIG. 38 . 
           [0057]      FIG. 40  is a schematic view for showing magnetic flux of the TFPM shown in  FIG. 38 . 
           [0058]      FIG. 41  is a side view showing the left core shown in  FIG. 38 . 
           [0059]      FIG. 42  is a side view showing a stator core of the TFPMs shown in  FIG. 38 . 
           [0060]      FIG. 43  is a schematic development showing arrangement of stator teeth shown in  FIG. 38 . 
           [0061]      FIG. 44  is a schematic development showing arrangement of pole-areas of a permanent magnet cylinder shown in  FIG. 38 . 
           [0062]      FIG. 45  is an axial cross-section showing six transverse flux switched reluctance machines (TFSRMs) arranged in tandem. 
           [0063]      FIG. 46  is a circumferential development showing an arrangement of stator teeth shown in  FIG. 45 . 
           [0064]      FIG. 47  is a circumferential development showing an arrangement of rotor teeth shown in  FIG. 45 . 
           [0065]      FIG. 48  is an axial cross-section showing six transverse flux permanent magnet switched reluctance machines (TFPMSRMs) arranged in tandem. 
           [0066]      FIG. 49  is a circumferential development showing an arrangement of stator teeth shown in  FIG. 48 . 
           [0067]      FIG. 50  is a circumferential development showing an arrangement of rotor teeth shown in  FIG. 48 . 
           [0068]      FIG. 51  is a schematic view showing motions of the rotor of the DC-driven TFPMSRM shown in  FIG. 48 . 
           [0069]      FIG. 52  is a reference view showing motions of the rotor of a AC-driven TFSynRM with same structure as the DC-driven TFSRM shown in  FIG. 48 . 
           [0070]      FIG. 53  is an axial cross-section showing dual-three-phase TFIMs with a circumferential tandem arrangement. 
           [0071]      FIG. 54  is a schematic side view showing an arrangement of the TFIMs shown in  FIG. 53 . 
           [0072]      FIG. 55  is an axial cross-section for illustrating separated stator cores and teeth-holders shown in  FIG. 53 . 
           [0073]      FIG. 56  is a partial side view showing a stator core shown in  FIG. 53 . 
           [0074]      FIG. 57  is a developed side view showing the TFM shown in  FIG. 53 . 
           [0075]      FIG. 58  is an axial cross-section showing the stator core shown in  FIG. 53 . 
           [0076]      FIG. 59  is a circumferential development of one arrangement of the stator teeth shown in  FIG. 53 . 
           [0077]      FIG. 60  is a circumferential development of another arrangement of the stator teeth shown in  FIG. 53 . 
           [0078]      FIG. 61  is a schematic side view showing another arrangement of the TFIMs shown in  FIG. 53 . 
           [0079]      FIG. 62  is a circumferential development of rotor teeth shown in  FIG. 53 . 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0080]      FIGS. 3-62  show five embodiments for showing the centipede-shaped TFMA (called the CTFMA) having the laminated core with diagonal portions for connecting teeth to a core back.  FIGS. 3-13  for showing a first embodiment disclose the tandem TFIM technology and the tandem TFSynRM technology having the TFIMs (transverse flux induction machines) or the TFSynRMs (transverse flux synchronous reluctance machines).  FIGS. 14-27  for showing a second embodiment disclose the tandem TFWRM technology having three TFWRMs (transverse flux wound rotor machines).  FIGS. 28-44  for showing a third embodiment disclose the tandem TFPM technology having three TFPMs (transverse flux permanent magnet machines).  FIGS. 45-52  for showing a fourth embodiment disclose the tandem TFSRM technology having six or three TFSRMs (transverse flux switched reluctance machines) or TFPMSRMs (transverse flux switched reluctance machines).  FIGS. 53-62  for showing a fifth embodiment disclose the circumferential-tandem TFIM technology having three TFIMs. The circumferential-tandem TFIM means the TFIM with stator cores arranged in tandem to the circumferential direction. The above circumferential-tandem structure can be employed by the other CTFMs. A part of technologies disclosed in the below embodiments are useful for known TFMs with conventional core structure. 
       The First Embodiment 
       [0081]    The TFMA shown in  FIG. 3  has three single-phase TFIMs arranged axially in tandem. A U-phase TFIM has a U-phase stator  1 U and a U-phase rotor core  4 U. A V-phase TFIM has a V-phase stator  1 V and a V-phase rotor core  4 V. A W-phase TFIM has a W-phase stator  1 W and a W-phase rotor core  4 W. The stators  1 U,  1 V and  1 W are fixed to a stator housing  100 . U-phase stator  1 U has a U-phase stator core  2 U accommodating a U-phase winding  3 U. V-phase stator  1 V has a V-phase stator core  2 V accommodating a V-phase winding  3 V. W-phase stator  1 W has a W-phase stator core  2 W accommodating a W-phase winding  3 W. The stator cores  2 U,  2 V and  2 W and the phase windings  3 U,  3 V and  3 W have ring shape each. 
         [0082]    The stator housing  100  has a disc-shaped front housing  101  and a barrel-shaped rear housing  102 . The front housing  101 , a teeth-holder  1   a,  U-phase stator core  2 U, a teeth-holder  1   b,  V-phase stator core  2 V, a teeth-holder  1   c,  W-phase stator core  2 W, a teeth-holder  1   d  and a disc portion of the rear housing  102  are arranged in turn to an axial direction AX of the rotor shaft  201 . Detailed structure of teeth-holders  1   a - 1   d,  the stator cores  2 U,  2 V and  2 W and the rotor cores  4 U,  4 V and  4 W are explained later. 
         [0083]    A cooling conduit  400  is wound in each ring-shaped concave portion of teeth-holders  1   a - 1   d . The concave portions extend to the circumferential direction PH along outer circumferential surfaces of teeth-holders  1   a - 1   d  made of aluminum. Rear housing  102  accommodates stators  1 U- 1 W, teeth-holders  1   a - 1   d  and the cooling conduit  400 . Cooling fluid flows through the cooling conduit  400 . An inner circumferential surface of a cylinder portion of the rear housing  102  comes into contact with outer circumferential surfaces of stator cores  2 U- 2 W, teeth-holders  1   a - 1   d  and the cooling conduit  400 . Preferably, teeth-holders  1   a - 1   d  come into contact with stator cores  2 U- 2 W across insulation layers (not shown) for reducing eddy currents. The insulation layers are made with same process as resin layers inserted in gaps  71   g  and  74   g  between two soft iron plates  7  shown in  FIG. 4 . 
         [0084]    Rotor cores  4 U,  4 V and  4 W arranged axially in tandem are fixed to a rotor housing  200  made with the die-casting method. The rotor housing  200  made of aluminum or copper is fixed to the rotor shaft  201 . Stator housing  100  holds the rotor shaft  201  via bearings. Rotor housing  200  constitutes so-called squirrel-cage secondary windings of three single-phase TFIMs. Rotor housing  200  has three ring-shape portions  40  disposed in three ring-shaped slots of rotor cores  4 U- 4 W. Each of rotor cores  4 U- 4 W faces each of stator cores  2 U- 2 W. A rotor shaft  201  has a heat pipe  202  extending axially. A cooling disc  203  made of a copper plate is fixed to rotor shaft  201  at an adjacent position to an outer end surface of rear housing  102 . Cooling disc  203  is covered with a resin case  206  having an inlet  204  and an outlet  205 . Air boundary layers on the cooling disc  203  remove both disc surfaces of the cooling disc  203  with own centrifugal force, when cooling disc  203  rotates. Generated heat of rotor housing  200  and rotor cores  4 U- 4 W are transferred to cooling disc  203  via rotor shaft  201  with heat pipe  202 . Steam or vapor in heat pipe  202  flows to the rear direction. Heat pipe  202  does not need structure for returning condensed liquid because all portions of cylinder-shaped liquid surface in the rotating heat pipe  202  have equal distance from an axial center line of rotor shaft  201 . In other words, the heat-transferring capability of the heat pipe is excellent because the condensed liquid returns with own centrifugal force. 
         [0085]    U-phase stator  1 U with U-phase stator core  2 U and U-phase winding  3 U is explained referring to  FIGS. 4-6 . Other stators  1 V and  1 W are the same as U-phase stator  1 U. Each of rotor cores  4 U- 4 W has the same structure as U-phase stator core  2 U. Stator core  2 U consists of left stator teeth  21 L, right stator teeth  21 R, a ring-shaped yoke portion  24 , left diagonal portions  25 L and right diagonal portions  25 R. Stator teeth  21 L and  21 R project inward to the radial direction RA. Ring-shaped yoke portion  24  extends to a circumferential direction PH. Left stator tooth  21 L, right stator teeth  21 R, left diagonal portions  25 L and right diagonal portions  25 R are arranged to the circumferential direction PH each. 
         [0086]    Each left diagonal portion  25 L joins each left stator tooth  21 L and yoke portion  24 . Each right diagonal portion  25 R joins each right stator tooth  21 R and yoke portion  24 . Left diagonal portions  25 L extend diagonally from yoke portion  24  toward the forward direction. Right diagonal portions  25 R extend diagonally from yoke portion  24  toward the rear direction. Left stator teeth  21 L and right stator teeth  21 R are adjacent to each other in the axial direction AX across the ring-shaped U-phase winding  3 U accommodated in a ring-shaped slot of U-phase core  2 U. Ring-shaped resin spacer  800  with triangle-shaped cross-section is inserted in upper portions of the slot between left stator teeth  21 L and right stator teeth  21 R. 
         [0087]    As shown in  FIG. 4 , stator core  2 U consists of six soft iron plates  7  laminated axially. Each plate  7  consists of left teeth  71 L, right teeth  71 R, a ring-shaped yoke portion  74 , left diagonal portions  75 L and right diagonal portions  75 R. The left teeth  71 L and the right teeth  71 R project inward to the radial direction RA. The yoke portion  74  extends to the circumferential direction PH. Each left diagonal portion  75 L extending diagonally joins each of left teeth  71 L and yoke portion  74 . Each of the right diagonal portion  75 R extending diagonally joins each of right teeth  71 R and yoke portion  74 . Therefore, stator core  2 U consists of a plurality of axially laminated soft iron plates  7 . Similarly, another stator cores  4 V and  4 W and rotor cores  4 U,  4 V and  4 W consist of a plurality of axially laminated soft iron plates as well as stator core  4 U. Left diagonal portions  75 L extending straightly to the diagonal direction is formed by means of pressing a flat iron plate. Right diagonal portions  75 R formed by means of pressing the flat iron plate extend straightly to the diagonal direction. 
         [0088]    A soft iron plate laminated helically can be employed instead of a plurality of soft iron plates  7  stacked axially. It is considered that each ring-shaped gap  74   g  is formed between each pair of yoke portions  74  being adjacent to each other. Similarly, each teeth-shaped gap  71   g  is formed between each pair of left teeth  71 L being adjacent to each other in the axial direction AX. Similarly, each teeth-shaped gap  71   g  is formed between each pair of right teeth  71 R being adjacent to each other in the axial direction AX. Each of the gaps  74   g  and  71   g  are buried with each resin layer including soft iron powder. The resin layer reduces harmonic components of an iron loss. Instead of using the resin layers, yoke portions  74  and teeth  71 L and  71 R can be curved or bent or projected to the axial direction AX for reducing magnetic vibration. After all, stator core  2 U is constructed by means of axially laminating process of a plurality of soft iron plates  7 . 
         [0089]      FIG. 5  is a partial side view showing a part of stator core  2 U schematically.  FIG. 6  is a partial plan view showing a part of stator core  2 U schematically. Left stator teeth  21 L and right stator teeth  21 R are arranged alternately in the circumferential direction PH. Two left stator teeth  21 L are adjacent to each other across a space with a circumferential width being mostly equal to one stator tooth  21 L. Similarly, two right stator teeth  21 R are adjacent to each other across a space with a circumferential width being mostly equal to one stator tooth  21 R. Left diagonal portions  25 L and right diagonal portions  25 R are arranged alternately in the circumferential direction PH. Two left diagonal portions  25 L are adjacent to each other across a space with a circumferential width being mostly equal to diagonal portion  25 L. Similarly, two right diagonal portions  25 R are adjacent to each other across a space with a circumferential width being mostly equal to diagonal portion  25 R. 
         [0090]    Each of rotor cores  4 U- 4 W consists of left rotor teeth  41 L, right rotor teeth  41 R, a ring-shaped yoke portion  44 , left diagonal portions  45 L and right diagonal portions  45 R. The left rotor teeth  41 L and the right rotor teeth  41 R project outward. The yoke portion  44  extends to the circumferential direction PH. Left rotor teeth  41 L, right rotor teeth  41 R, left diagonal portions  45 L and right diagonal portions  45 R are arranged to the circumferential direction PH each. Each left diagonal portion  45 L joins each left rotor tooth  41 L and yoke portion  44 . Each right diagonal portion  45 R joins each right rotor tooth  41 R and yoke portion  44 . Left diagonal portions  45 L extend diagonally from yoke portion  44  toward the forward direction. Right diagonal portions  45 R extend diagonally from yoke portion  44  toward the rear direction. Left rotor teeth  41 L and right rotor teeth  41 R are adjacent to each other in the axial direction AX across a ring-shaped slot buried with a ring portion  40  of rotor housing  200 . The ring portion  40  is a part of a squirrel-cage secondary winding. Left rotor teeth  41 L face left stator teeth  21 L in the radial direction RA. Right rotor teeth  41 R face right stator teeth  21 R in the radial direction RA. 
         [0091]    Stator teeth  21 L of stator core  2 U and rotor teeth  41 L of rotor core  4 U have a U-phase electric angle. Stator teeth  21 L of stator core  2 V and rotor teeth  41 L of rotor core  4 V have a V-phase electric angle. Stator teeth  21 L of stator core  2 W and rotor teeth  41 L of rotor core  4 W have a W-phase electric angle. Each angle between each two of the three phase electric angles is 120 degrees. After all, the TFMA shown in  FIG. 3  has three transverse flux single-phase induction machines (TFIMs).  FIG. 7  is a partial development showing one arrangement of rotor teeth  41 L and  41 R.  FIG. 8  is a partial development showing one arrangement of stator teeth  21 L and  21 R. 
         [0092]      FIG. 9  is a block circuit configuration showing the TFMA with three TFIMs shown in  FIG. 3 . Three-phase inverter  9  applies a U-phase voltage Vu, a V-phase voltage Vv and a W-phase voltage Vw to three single-phase windings  3 U- 3 W of the three TFIMs respectively. A rotor angle detected from the TFIMs is transmitted to controller  300  having an induction-motor mode and a reluctance-motor mode. The three TFIMs are capable of generating a reluctance torque each because each of the TFIMs has the dual-salient structure. In other words, stator cores  2 U- 2 W are salient type and rotor cores  4 U- 4 W are salient type. Thus, reluctances of three TFIMs are changed in accordance with the rotor angle. On the other hand, each of three TFIMs is not capable of generating the starting torque because the three TFIMs are a single-phase induction motor each. After all, three TFIMs are operated as three single-phase synchronous reluctance motors or three single-phase switched reluctance motors in a starting period. 
         [0093]      FIG. 10  is a flow chart showing the selection of either one of the above two modes. First, information including a rotor position, a rotor angular speed and a torque instruction value are detected at the step S 200 . At next step S 202 , an induction motor torque Ti and a synchronous reluctance torque Tr are calculated in accordance with the detected information and a memorized map. The induction motor torque Ti is zero, when the speed of the TFIMs is zero. Each TFIM is capable of generating the synchronous reluctance torque Tr, (=(Ld−Lq)IdIq) because each of phase windings  3 U- 3 W has a difference between a d-axis inductance Ld and a q-axis inductance Lq each. The torque Tr is calculated in accordance with the d-axis inductance Ld, the q-axis inductance Lq, a d-axis current Id and a q-axis current Iq. 
         [0094]    After the starting of the TFIMs as the synchronous reluctance motors (TFSynRMs) or the switched reluctance motors (TFSRMs), it is judged whether or not an induction-motor mode is better in accordance with efficiency and the torque values at the step S 202 . The induction-motor mode is selected under conditions that an efficiency of the induction motor operation is higher than an efficiency of the reluctance motor operation. The induction-motor mode is selected at step S 204 , and the reluctance-motor mode is selected at step S 206 . According to another case, it is further judged whether or not a rotor temperature is higher than a predetermined threshold value at the step S 202 . The reluctance-motor mode is selected, when the rotor temperature is higher because the copper loss of the rotor is decreased by means of employing the reluctance-motor mode. 
         [0095]      FIG. 11  is a schematic block circuit configuration showing an example of electric power system for driving the above TFIMs employed by series-hybrid vehicle car. The electric power system consists of an engine-side motor-generator (MG 1 ), a wheel-side motor-generator (MG 2 ), an engine-side three-phase inverter  9 E, a wheel-side three-phase inverter  9 F, and a DC power source  9 G and a connection-changing relay  9 H. Each of the motor-generators MG 1  and MG 2  consists of three TFIMs shown in  FIG. 3 . Three phase windings  3 U 1 ,  3 V 1  and  3 W 1  of the MG 1  are connected to three legs (not shown) of the three-phase inverter  9 E respectively. Three phase windings  3 U 2 ,  3 V 2  and  3 W 2  of the MG 2  are connected to three legs (not shown) of the three-phase inverter  9 F respectively. A high potential terminal of the DC power source  9 G is connected to high potential terminals of inverters  9 E and  9 F. The connection-changing relay  9 H connects three phase windings  3 U 1 ,  3 V 1  and  3 W 1  and three phase windings  3 U 2 ,  3 V 2  and  3 W 2  respectively. 
         [0096]    Three phase windings  3 U 1 ,  3 V 1  and  3 W 1  have three phase voltages Vu 1 , Vv 1  and Vw 1  respectively. Each phase difference among the three phase voltages Vu 1 , Vv 1  and Vw 1  is 120 degrees of electric angle. Three phase windings  3 U 2 ,  3 V 2  and  3 W 2  have three phase voltages Vu 2 , Vv 2  and Vw 2  respectively. Each phase difference among the three phase voltages Vu 2 , Vv 2  and Vw 2  is 120 degrees of electric angle. Controller  300  controls frequencies and voltages of six voltages Vu 1 , Vv 1 , Vw 1 , Vu 2 , Vv 2  and Vw 2 . A common frequency ‘fo’ is selected under conditions that the MG 1  is operated as a generator and the MG 2  is operated as a motor. Voltages Vu 1 , Vv 1  and Vw 1  have a synchronous frequency f 1 , which is corresponding to the rotor speed of the MG 1 . Voltages Vu 2 , Vv 2  and Vw 2  have a synchronous frequency f 2 , which is corresponding to the rotor speed of the MG 2 . Connection-changing relay  9 H is turned on, when a difference between two synchronous frequencies f 1  and f 2  is small. Therefore, U-phase winding  3 U 1  and  3 U 2  are connected directly. V-phase winding  3 V 1  and  3 V 2  are connected directly. W-phase winding  3 W 1  and  3 W 2  are connected directly. A output power of an internal combustion engine connected to the motor-generator MG 1  is controlled to keep efficiencies of motor-generators MG 1  and MG 2  high. After all, the six phase voltages Vu 1 , Vv 1 , Vw 1 , Vu 2 , Vv 2  and Vw 2  have a common frequency ‘fo’ each. 
         [0097]      FIG. 12  shows the common frequency ‘fo’, an equivalent synchronous frequency ‘fg’ of the MG 1  and an equivalent synchronous frequency ‘fm’ of MG 2 . The equivalent synchronous frequency ‘fg’ is equivalent to the rotor speed of the MG 1 . The equivalent synchronous frequency ‘fm’ of MG 2  is equivalent to the rotor speed of the MG 2 . The common frequency ‘fo’ has an intermediate value between the equivalent synchronous frequencies ‘fg’ and ‘fm’. Therefore, the MG 1  has a slip rate ‘Sm’, and the MG 2  has a slip rate ‘Sg’, when relay  9 H are turned on. The common frequency ‘fo’ is controlled in order to realize the current balance between the MG 1  and the MG 2 . Inverters  9 E and  9 F can be stopped, when the relay  9 H is turned on. 
         [0098]      FIG. 13  shows a flow-chart showing one control example of the connection-changing relay  9 H. Firstly, information including rotor speeds of MG 1  and MG 2  are detected at the step S 300 . At next step S 302 , it is judged whether or not the connection state of the relay  9 H should be changed from the turning-on state to the turning-off state or from the turning-off state to the turning-on state. The relay  9 H is turned, when the currents of inverters  9 E and  9 F have the common frequency ‘fo’. In other words, the inverter  9 E and  9 F are driven with the common frequency ‘fo’ before the turning-on or the turning-off of relay  9 H at the step S 304 . A current difference between the MG 1  and the MG 2  is reduced by means controlling the common frequency ‘fo’ and six phase voltages Vu 1 -Vw 2 . At next step S 306 , it is judged whether or not a relay current ‘Irelay’ of relay  9 H is lower than a predetermined value. After the relay current ‘Irelay’ becomes smaller than the predetermined value, the state of relay  9 H is changed at a step S 308 . Accordingly, spark of the relay is reduced. 
       A First Arranged Embodiment 
       [0099]    The first arranged embodiment of the first embodiment is explained. The TFIMs shown in  FIG. 3  become an axially tandem transverse flux single-phase synchronous reluctance machines (TFSynRMs) or an axially tandem transverse flux single-phase switched reluctance machines (TFSRMs) by means of abbreviating three ring portions  40  of rotor cores  4 U- 4 W. 
       The Second Embodiment 
       [0100]      FIG. 14  is an axial cross-section showing the TFMA having three TFWRMs (transverse flux wound-rotor machines) arranged axially in tandem. The three TFWRMs shown in  FIG. 14  have field windings  6 U,  6 V and  6 W and secondary windings  60 U,  60 V and  60 W wound on ring-shaped spaces of rotor cores  4 U,  4 V and  4 W. The ring-shaped spaces are formed by means of abbreviating ring portions  40  shown in  FIG. 3 . The ring-shaped U-phase field windings  6 U and the ring-shaped U-phase secondary windings  60 U are accommodated in a ring-shaped space between left teeth  41 L and right teeth  41 R of U-phase rotor core  4 U. The ring-shaped V-phase field windings  6 V and the ring-shaped V-phase secondary windings  60 V are accommodated in a ring-shaped space between left teeth  41 L and right teeth  41 R of V-phase rotor core  4 V. The ring-shaped W-phase field windings  6 W and the ring-shaped W-phase secondary windings  60 W are accommodated in a ring-shaped space between left teeth  41 L and right teeth  41 R of W-phase rotor core  4 W. 
         [0101]    A rotor circuit of the three TFWRMs shown in  FIG. 14  is shown in  FIG. 15 . Secondary windings  60 U,  60 V and  60 W having the star-connection supplies a field current ‘If’ to field windings  6 U,  6 V and  6 W via a three-phase full-wave diode rectifier  600 A. Field windings  6 U,  6 V and  6 W are connected in series to each other. Instead of the rectifier  600 A shown in  FIG. 15 , a three-phase half-wave diode rectifier can be employed. Further, each of secondary windings  60 U,  60 V and  60 W performing as the field winding can be short-circuited through each diode.  FIG. 16  shows a three-phase inverter  9  connected to three single-phase windings  3 U,  3 V and  3 W wound on three stator cores  2 U,  2 V and  2 W respectively. The inverter  9  can perform as a rectifier, when the TFWRMs work as the three-phase generator. 
         [0102]    The inverter  9  supplies a symmetrical three-phase excitation current ‘Ih’ consisting of a U-phase excitation current ‘IUh’, a V-phase excitation current ‘IVh’ and a W-phase excitation current ‘IWh’. Further, the inverter  9  supplies a symmetrical three-phase fundamental stator current ‘I 0 ’ consisting of a U-phase fundamental current ‘IU 0 ’, a V-phase fundamental current ‘IV 0 ’ and a W-phase fundamental current ‘IW 0 ’. Frequencies of fundamental current ‘I 0 ’ and excitation current ‘Ih’ are shown in  FIG. 17 . In  FIG. 16 , the currents ‘I 0 ’ and ‘Ih’ has sinusoidal waveforms each. A frequency ‘fh’ of excitation current ‘Ih’ is higher than a frequency ‘f 0 ’ of fundamental current ‘I 0 ’. A slip rate ‘S’ is equal to a value of (fh−f 0 )/fh. In order to induce each secondary voltage across each of three of secondary windings  60 U,  60 V and  60 W, it is capable of employing spatial harmonics of magnet motive force (MMF) applied to rotor teeth  41 L and  41 R of rotor  4 . In other words, the dual-salient structure of the TFWRM shown in  FIG. 14  excites the spatial harmonics of the magnet motive force, even though currents with sinusoidal waveforms are supplied to three single-phase windings  3 U,  3 V and  3 W, because the magnet motive force is modulated spatially. The harmonics of the magnet motive force (MMF) induce an alternative secondary voltage across each of secondary windings  60 U,  60 V and  60 W. 
         [0103]    According to another case, each of phase currents supplied to three single-phase windings  3 U,  3 V and  3 W has a trapezoidal waveform each as shown in  FIG. 18 . The current with trapezoid waveform includes many harmonic components in addition to the fundamental current I 0 . 
         [0104]    A torque control example of the TFWRM is explained referring to  FIG. 19 . At a step S 400 , a torque instruction value ‘Ti’ is read. At next step S 402 , a waveform and an amplitude of the phase currents with trapezoid waveforms are searched from memorized map. A current-changing rate and an amplitude of the phase currents are increased at a step S 404 , when the torque instruction value ‘Ti’ is large. The current-changing rate and the amplitude of the phase currents are decreased at the step S 404 , when the torque instruction value ‘Ti’ is small. Furthermore, the excitation current ‘Ih’ with high frequency is added to the trapezoid phase currents, when the motor speed is low. Because, the frequency of the induced secondary current is decreased, when the motor speed is low. After all, the secondary current is induced by means of the supplying of the fundamental current ‘I 0 ’ with trapezoid waveforms or the supplying of the excitation current ‘Ih’ or the using of the spatial modulation of dual-salient structure of the TFWRM. The inverter  9  supplies the decided fundamental current ‘I 0 ’ and the decided excitation current ‘Ih’. 
         [0105]    The secondary windings  60 U,  60 V and  60 W do not require many turns because the field windings  6 U,  6 V and  6 W seem to resistance elements and the frequency of the excitation current Ih is high. Further, a sum of voltages induced across the field windings  6 U,  6 V and  6 W connected in series becomes mostly zero, when the symmetrical three-phase fundamental current I 0  is supplied. 
         [0106]      FIG. 20  shows one arrangement of the rotor teeth  41 L and  41 R. The left teeth  41 L of U-phase rotor core  4 U, the right teeth  41 R of V-phase rotor core  4 V and the left teeth  41 L of W-phase rotor core  4 W is magnetized to N-poles. The right teeth  41 R of U-phase rotor core  4 U, the left teeth  41 L of V-phase rotor core  4 V and the right teeth  41 R of W-phase rotor core  4 W is magnetized to S-poles.  FIG. 21  shows one arrangement of the left teeth  21 L and the right teeth  21 R of stator  1 . 
         [0107]      FIGS. 22-25  show circumferential positions of U-phase left teeth  41 L of U-phase rotor core  4 U. The left teeth  41 L is magnetized to N-poles. At a first rotor position shown in  FIG. 22 , top surfaces of left teeth  21 L is magnetized to S-poles. The left teeth  41 L is attracted by the left teeth  21 L. At a second rotor position shown in  FIG. 23 , U-phase fundamental current Iu is stopped. At a third rotor position shown in  FIG. 24 , top surfaces of left teeth  21 L is magnetized to N-poles. The repulsion force is given to the left teeth  41 L with N-poles. At a fourth rotor position shown in  FIG. 25 , U-phase fundamental current Iu is stopped. 
       A First Arranged Embodiment 
       [0108]    The first arranged embodiment of the TFWRM shown in  FIG. 14  is explained referring to  FIGS. 26 and 27 .  FIG. 26  is an axial cross-section showing another TFMA having three TFWRMs arranged axially in tandem. The three TFWRMs shown in  FIG. 26  is essentially same as the three TFWRMs shown in  FIG. 14  except the addition of primary field windings  30 U,  30 V and  30 W wound in the three ring-shaped slots of stator cores  3 U,  3 V and  3 W respectively. The ring-shaped phase primary field windings  30 U is wound on stator core  2 U. The ring-shaped V-phase primary field windings  30 V is wound on stator core  2 V. The ring-shaped W-phase primary field windings  30 W is wound on stator core  2 W.  FIG. 26  further shows the cooling air passages through which the cooling air (C.A.) flows. The cooling air (C.A.) is generated by the rotation of teeth  41 L and  41 R. 
         [0109]      FIG. 27  is a circuit topology configuration showing a stator circuit  9000  and a rotor circuit  3000 . The stator circuit  9000  provided at the stator-side has the three-phase inverter  9 , a regulation transistor  90  and a freewheeling diode  300 . The three-phase inverter  9  is changed to a three-phase full-bridge diode rectifier, when the TFWRM is only driven as the generator. The regulation transistor  90  is PWM-switched in order to control a primary field current If 1  flowing through the primary field windings  30 U,  30 V and  30 W connected in series. The freewheeling diode  300  is connected in parallel to primary field windings  30 U,  30 V and  30 W. The rotor circuit  3000  shown in  FIG. 27  is the same as the rotor circuit shown in  FIG. 15 . 
         [0110]    Generator operation of the TFWRM shown in  FIGS. 26-27  is explained as follows. The primary field current If 1  is supplied to primary field windings  30 U,  30 V and  30 W connected in series. Thus, teeth  21 L of U-phase stator cores  2 U, teeth  21 R of V-phase stator core  2 V and teeth  21 L of W-phase stator core  2 W are magnetized to N-poles. Thus, a U-phase voltage VU 2 , a V-phase voltage VV 2  and a W-phase voltage VW 2  are induced across three secondary windings  60 U,  60 V and  60 W respectively. Rectifier  600 A rectifies the three-phase secondary voltage consisting of the U-phase voltage VU 2 , the V-phase voltage VV 2  and the W-phase voltage VW 2 , and supplies the rectified field current If to field windings  6 U,  6 V and  6 W. Therefore, teeth  41 L and  41 R are magnetized. It is desirable that teeth  41 L of U-phase rotor cores  4 U, teeth  41 R of V-phase rotor core  4 V and teeth  41 L of W-phase rotor core  4 W are magnetized to S-poles. In other words, field current If and primary field current If 1  flow to the same direction in the circumferential direction PH. Accordingly, three of alternative voltages are induced across three single-phase windings  3 U,  3 V and  3 W respectively. The rectifier  9  rectifies the induced three-phase voltage. 
         [0111]    Field windings  6 U,  6 V and  6 W have a larger number of turns than secondary windings  60 U,  60 V and  60 W and primary field windings  30 U,  30 V and  30 W. It is desirable that each of field windings  6 U,  6 V and  6 W has more than five times, more particularly more than ten times of the turns than each of secondary windings  60 U,  60 V and  60 W and each of primary field windings  30 U,  30 V and  30 W. Accordingly, field windings  6 U,  6 V and  6 W with a large inductance storage a large magnetic energy. It means to excite large magnetic flux. Furthermore, the ripple of field current If is reduced. A sum of the inductances of primary field windings  30 U,  30 V and  30 W and a sum of the inductances of field windings  6 U,  6 V and  6 W are almost constant each even though the rotor is rotated. In other words, a sum of overlapping areas (facing areas to each other) of stator teeth  21 L and  21 R and rotor teeth  41 L and  41 R of the three TFWRMs are almost constant even though the rotor is rotated. Therefore, a sum of the voltages induced across the primary field windings  30 U,  30 V and  30 W becomes almost zero. Similarly, a sum of the induced voltages of the field windings  6 U,  6 V and  6 W becomes almost zero. It is important that an electric power consumed as a copper loss of field windings  6 U- 6 W is supplied from the mechanical energy of the rotor. Further, the turn number of windings  30 U- 30 W and  60 U- 60 W are reduced because the TFWRM is capable of having a large number of teeth  21 L- 21 R and  41 L- 41 R even though the TFWRM is the unipolar type. According to another arranged embodiment, primary field windings  30 U- 30 W are abbreviated. Instead of the current If 1 , it is capable to flow a DC primary field current If 1  to single-phase windings  3 U- 3 W each. 
       A Third Embodiment 
       [0112]      FIG. 28  is a schematic axial cross-section showing the tandem TFMA having three TFPMs arranged axially in tandem. Stator  1  is essentially same as stator  1  shown in  FIG. 3 . However, the TFPM shown in  FIG. 28  does not have a rotor core  4 U- 4 W made of iron plates. The rotor  4  shown in  FIG. 28  consists of permanent magnet cylinder  600  fixed to an outer circumferential surface of non-magnetic rotor portion  605  of rotor  4 . An outer circumferential surface of the permanent magnet cylinder  600  has N-pole areas  6 N and S-pole areas  6 S arranged alternately to the circumferential direction as shown in  FIG. 29 .  FIG. 30  shows stator teeth  21 L and  21 R of stator cores  4 U- 4 W. The rotor  4  is rotated by means of supplying the three-phase currents to three single-phase windings  3 U- 3 W. 
         [0113]      FIGS. 31 and 32  show magnetization process of permanent magnet cylinder  600 . At first, N-pole areas N 1  of odd numbered lines and S-pole areas Si of even numbered lines are magnetized as shown in  FIG. 31 . The N-pole areas N 1  is formed at different columns from the S-pole areas S 1 . At next, N-pole areas N 2  of odd numbered lines and S-pole areas S 2  of even numbered lines are magnetized as shown in  FIG. 32 . The N-pole areas N 2  is formed at different columns from the S-pole areas S 2 . Therefore, the permanent magnet cylinder  600  is not magnetized to the circumferential direction PH. In other words, circumferential magnetic flux passages from S-pole areas S 2  to N-pole areas N 1  and circumferential magnetic flux passages from S-pole areas S 1  to N-pole areas N 2  are made, when all pole areas N 1 , N 2 , S 1  and S 2  are magnetized simultaneously. The above circumferential magnetic flux passages makes saddle-shaped magnetic flux passages in U-phase stator core  2 U and U-phase rotor core  4 U, when stator teeth  21 L face both of adjacent N-pole areas N 1  and S-pole areas S 2 . The above saddle-shaped magnetic flux passages do not cross-link to U-phase winding  3 U. It causes to reduce the motor torque largely. It is restrained to make the saddle-shaped magnetic flux passages, when adjacent two pole areas are magnetized in turn. 
       A First Arranged Embodiment 
       [0114]      FIGS. 33-37  show another TFMA having TFPMs.  FIG. 33  is an axial cross-section of three TFPM arranged axially in tandem. The stator cores  2 U,  2 V and  2 W shown in  FIG. 33  are essentially same as the stator cores  2 U,  2 V and  2 W shown in  FIG. 3 . However, the stator cores  2 U,  2 V and  2 W shown in  FIG. 33  further have ring portions  27  and lower diagonal portions  250 L and  250 R. Furthermore, the stator cores  2 U,  2 V and  2 W shown in  FIG. 33  have segmented yoke portions  24 L and  24 R instead of the ring-shaped yoke portion  24  employed in  FIG. 3 . 
         [0115]    According to  FIG. 33 , three stator cores  2 U,  2 V and  2 W are constructed with a left core  2 L, two center cores  2 C 1  and  2 C 2  and a right core  2 R. The ring-shaped cores  2 L,  2 C 1 ,  2 C 2  and  2 R are arranged to the axial direction AX in turn. Cores  2 L,  2 C  1 ,  2 C 2  and  2 R are made of the axially laminated iron plates respectively. Ring-shaped rotor cores  4 U,  4 V and  4 W are made of the axially laminated iron plates respectively. Rotor cores  4 U,  4 V and  4 W have conventional cylinder shape each. Each of three permanent magnet rings  10  is fixed on each outer circumferential surface of rotor cores  4 U,  4 V and  4 W. It is capable of inserting a predetermined number of permanent magnets into slots of rotor cores  4 U,  4 V and  4 W. The stator core structure shown in  FIG. 33  can be employed by the other TFMs except the TFPM, too.  FIG. 34  is a circumferential development showing three permanent magnet rings  10 . Each permanent magnet ring  10  has N-pole areas N and S-pole areas S arranged alternately in the circumferential direction PH. 
         [0116]      FIG. 35  shows construction process of the stator cores  2 U,  2 V and  2 W shown in  FIG. 33 . One left core  2 L, two center cores  2 C 1  and  2 C 2  and one right core  2 R are provided. However, the center cores  2 C 2  is not illustrated in  FIG. 35  because of limitation of the paper sheet. Left core  2 L consists of left yoke portions  24 L, upper left diagonal portions  25 L, a ring-shaped ring portion  27 , lower left diagonal portions  250 L and left teeth  21 L. The upper left diagonal portions  25 L project diagonally and outward from the ring portion  27 . Each yoke portion  24 L projects outward from each upper left diagonal portion  25 L. The lower left diagonal portions  250 L project diagonally and inward from ring portion  27 . Each left teeth  21 L projects from each lower left diagonal portion  250 L. The portions  21 L,  250 L,  25 L and  24 L are arranged to the circumferential direction PH each. The right core  2 R consists of right yoke portions  24 R, upper right diagonal portions  25 R, a ring-shaped ring portion  27 , lower right diagonal portions  250 R and right teeth  21 R. Each upper right diagonal portion  25 R projects diagonally and outward from the ring portion  27 . Each of right yoke portions  24 R projects outward from each of upper right diagonal portions  25 R. The lower right diagonal portions  250 R project diagonally from ring portion  27 . Each of right teeth  21 R projects inward from each of lower right diagonal portions  250 R. The portions  21 R,  250 R,  25 R and  24 R are arranged to the circumferential direction PH each. 
         [0117]    Each of center cores  2 C 1  and  2 C 2  consists of the left yoke portions  24 L, the right yoke portions  24 R, the upper left diagonal portions  25 L, the upper right diagonal portions  25 R, a ring-shaped ring portion  27 , the lower left diagonal portions  250 L, the lower right diagonal portions  250 R, the left teeth  21 L and the right teeth  21 R. The diagonal portions  25 R and  25 L arranged alternately in the circumferential direction PH project diagonally from ring portion  27 . Each yoke portion  24 R projects outward from each diagonal portion  25 R. Each yoke portion  24 L projects outward from each diagonal portion  25 L. The diagonal portions  250 R and  250 L arranged alternately in the circumferential direction PH project diagonally from ring portion  27 . Each right teeth  21 R projects inward from each portion  250 R. Each left teeth  21 L projects inward from each portion  250 L. The portions  21 L,  21 R,  24 L,  24 R,  25 L,  25 R,  250 L and  250 R are arranged to the circumferential direction PH each. 
         [0118]      FIG. 36  is a circumferential development of the left teeth  21 L and the right teeth  21 R.  FIG. 37  is a circumferential development of the left yoke portions  24 L and the right yoke portions  24 R. The left yoke portions  24 L and the right yoke portions  24 R of each phase are arranged alternately in the circumferential direction PH. Adjacent yoke portions  24 L and  24 R of each phase come into contact to each other in the circumferential direction PH and constitute the yoke portion  24 . 
       A Second Arranged Embodiment 
       [0119]      FIGS. 38-44  show another TFMA having TFPMs.  FIG. 38  is an axial cross-section of three TFPM arranged axially in tandem. The stator cores  2 U,  2 V and  2 W shown in  FIG. 38  are essentially same as stator cores  2 U,  2 V and  2 W shown in  FIG. 33 . Stator cores  2 U,  2 V and  2 W consist of the left stator core  2 L, the center cores  2 C 1  and  2 C 2  and the right core  2 R. However, stator cores  2 U,  2 V and  2 W shown in  FIG. 38  do not have the lower diagonal portions  250 L and  250 R and the teeth  21 L and  21 R shown in  FIG. 33 . Stator cores  2 L,  2 C 1 ,  2 C 2  and  2 R shown in  FIG. 38  have teeth  211 - 214  respectively. The left stator core  2 L has the teeth  211  projecting from ring portion  27 . The left-center stator core  2 C 1  has the teeth  212  projecting from ring portion  27 . The right-center stator core  2 C 2  has the teeth  213  projecting from ring portion  27 . The right stator core  2 R has the teeth  214  projecting from ring portion  27 . 
         [0120]      FIG. 39  shows stator cores  2 L,  2 C 1 ,  2 C 2  and  2 R separated to each other. Teeth-shaped yoke portions  24 L of left stator core  2 L and teeth-shaped yoke portions  24 R of left-center stator core  2 C 1  are arranged alternately to circumferential direction PH. Teeth-shaped yoke portions  24 L of left-center stator core  2 C 1  and teeth-shaped yoke portions  24 R of right-center stator core  2 C 2  are arranged alternately to circumferential direction PH. Teeth-shaped yoke portions  24 L of right-center stator core  2 C 2  and teeth-shaped yoke portions  24 R of right stator core  2 R are arranged alternately to circumferential direction PH. 
         [0121]    Rotor  4  shown in  FIG. 38  has the cylinder-shaped permanent magnet  600  fixed on non-magnetic rotor portion  605 . Rotor  4  shown in  FIG. 47  is essentially same as rotor  4  shown in  FIG. 37  or a rotor of a conventional transverse flux permanent magnet machine (TFPM). 
         [0122]      FIG. 40  is a schematic view for showing magnetic flux of the TFPM shown in  FIG. 38 . Real lines show the magnetic flux of the permanent magnet  600 . Dotted lines show the magnetic flux excited by three-phase current Iu, Iv and Iw flowing into three phase windings  3 U,  3 V and  3 W. As shown in  FIG. 44 , the permanent magnet  600  has columns  601 - 604  consisting of N-pole areas and S pole-areas. As shown in  FIG. 40 , the column  601  supplies the magnetic flux Fu to teeth  211 . The column  602  supplies the magnetic flux Fw teeth  212 . The column  603  supplies the magnetic flux Fv and Fw to teeth  213 . The column  604  supplies the magnetic flux Fu and Fv to teeth  214 . Each phase differences between each two of the magnetic flux Fu, Fv and Fw is 120 electric degrees. In other words, the permanent magnet flux Fu, Fv and Fw penetrating into teeth  211 - 214  are modulated spatially by means of rotating the rotor  4 . 
         [0123]    The U-phase permanent magnet flux Fu cross-linked to U-phase winding  3 U has mostly the sinusoidal waveform, when rotor  4  rotates. Similarly,the V-phase permanent magnet flux Fv cross-linked to V-phase winding  3 V has mostly the sinusoidal waveform. Similarly,the W-phase permanent magnet flux Fw cross-linked to W-phase winding  3 W has mostly the sinusoidal waveform. Thus, the TFPM generates three-phase motor torque with three-phase sinusoidal waveform or three-phase generation voltage with three-phase sinusoidal waveform. 
         [0124]      FIG. 41  is a partial side view of the left core  2 L.  FIG. 42  is a partial side view of the U-phase stator core consisting of the left core  2 L and the left-center stator core  2 C 1 . Left core  2 L has left teeth  21 L, a ring portion  27 , left diagonal portions  25 L and left yoke portions  24 L. Left yoke portions  24 L and right yoke portions  24 R are arranged alternately in the circumferential direction PH and come into contact to each other. Yoke portions  24 L and  24 R constitute a ring-shaped yoke portion  24  shown in  FIG. 3 . Vibration of stator teeth  21 L and  21 R are decreased because stator teeth  21 L and  21 R project from ring portions  27 . Stator cores  2 V and  2 W have same structure as stator core  2 U. 
         [0125]      FIG. 43  is a schematic development showing the arrangement of stator teeth  211 - 214 . The arrangement of stator teeth  211 - 214  is different from arrangement of stator teeth  21 L and  21 R shown in  FIG. 46 . It is important that the circumferential positions of teeth  211 - 214  are free even though the cores  2 L,  2 C 1 ,  2 C 2  and  2 R are overlapped in the axial direction AX. 
         [0126]      FIG. 44  is a schematic circumferential development showing arrangement of pole areas N 1 -N 5  and S 1 -S 5  of permanent magnet cylinder  600 .  FIG. 44  shows four columns  601 - 604  of pole areas N 1 -N 5  and S 1 -S 5  of permanent magnet cylinder  600 .  FIG. 44  shows five lines  607 - 611  including the N-pole areas N 1 -N 5  and the S-pole areas S 1 -S 5 . Each of N-pole areas N 1 -N 5  and each of S-pole areas S 1 -S 5  are arranged alternately in the circumferential direction PH. Each of magnetized intermediate columns  605  is disposed between adjacent two of the columns  601 - 604  in order to form the magnetic flux passages in permanent magnet cylinder  600 . The intermediate column  605  is magnetized to axial direction AX. However, permanent magnet cylinder  600  in not magnetized to the circumferential direction PH. The even numbered columns  608  and  610  are magnetized after when the odd numbered columns  607 ,  609  and  611  have been magnetized in order to cancel the magnetic flux passages extending to the circumferential direction PH. 
       A Fourth Embodiment 
       [0127]    The fourth embodiment is explained referring to  FIGS. 45-52 .  FIGS. 45-52  disclose a TFMA having six single-phase transverse flux switched reluctance machines (TFSRMs) or six single-phase transverse flux permanent magnet switched reluctance machine (TFPMSRMs).  FIG. 45  is an axial cross-section showing six single-phase TFSRMs arranged axially in tandem.  FIG. 46  is a circumferential development showing stator teeth  21 L and  21 R of stator  1 . 
         [0128]    Stator  1  has a Ul-phase stator core  2 U 1 , a U 2 -phase stator core  2 U 2 , a V 1 -phase stator core  2 V 1 , a V 2 -phase stator core  2 V 2 , a W 1 -phase stator core  2 W 1  and and a W 2 -phase stator core  2 W 2 . The stator cores  2 U 1 - 2 W 2  have six phase windings  3 U 1 ,  3 U 2 ,  3 V 1 ,  3 V 2 ,  3 W 1  and  3 W 2  respectively. Each line with each arrow shown in  FIG. 46  shows each current direction of six phase currents I 1 -I 6  flowing through the phase windings  3 U 1 - 3 W 2  respectively.  FIG. 47  is a circumferential development showing an arrangement of rotor teeth  41 L and  41 R of six rotor cores  4 U 1 ,  4 U 2 ,  4 V 1 ,  4 V 2   4 W 1  and  4 W 2  of rotor  4 . Stator  1  and rotor  4  shown in  FIG. 45  is equal to stator  1  and rotor  4  shown in  FIG. 3 . However, rotor  4  shown in  FIG. 45  does not have ring portion  40  shown in  FIG. 3 . In  FIG. 46 , stator teeth  21 L of each phase are arranged at an equal circumferential position. In  FIG. 47 , adjacent two rotor cores have a spatial difference, which is equivalent to 60 electric angular degrees, in the circumferential direction. 
       A First Arranged Embodiment 
       [0129]    The first arranged embodiment of the fourth embodiment is explained referring to  FIGS. 48-52 .  FIGS. 48-50  show six transverse flux permanent magnet switched reluctance machines (called TFPMSRMs) arranged axially in tandem.  FIG. 48  is an axial cross-section showing the six-phase TFPMSRM. The TFPMSRMs shown in  FIGS. 48-50  are essentially same as the TFSRMs shown in  FIGS. 45-47  except a permanent magnet layer  6  shown in  FIG. 48 . The permanent magnet layer  6  is disposed in spaces among teeth  41 L and  41 R of six rotor cores  4 U 1 - 4 W 2  arranged axially in tandem. Permanent magnet layer  6  is made from ferrite magnet material covering outer circumferential surfaces of rotor cores  4 U 1 - 4 W 2  except top surfaces of the teeth  41 L and  41 R.  FIG. 49  is a circumferential development showing an arrangement of stator teeth  21 L and  21 R shown in  FIG. 48 .  FIG. 50  is a circumferential development showing an arrangement of rotor teeth  41 L and  41 R of rotor cores  4 U 1 - 4 W 2  and S-pole areas  6 S and N-pole areas  6 N of permanent magnet layer  6 . N-pole areas  6 N are disposed between each two left rotor teeth  41 L of rotor cores  4 U 1 ,  4 V 1  and  4 W 1  and between each two right rotor teeth  41 R of rotor cores  4 U 2 ,  4 V 2  and  4 W 2  in the circumferential direction PH. S-pole areas  6 S are disposed between each two right rotor teeth  41 R of rotor cores  4 U 1 ,  4 V 1  and  4 W 1  and between each two left rotor teeth  41 L of rotor cores  4 U 2 ,  4 V 2  and  4 W 2  in the circumferential direction PH. Phase currents  12 ,  14  and  16  flows to the opposite direction to phase currents I 1 , I 3  and I 5  as shown in  FIG. 49 . 
         [0130]    Each TFPMSRM shown in  FIG. 48  generates both of the switched reluctance torque and the permanent magnet torque simultaneously.  FIG. 51  is a schematic side view for showing four positions of left teeth  41 L of rotor core  4 U 1  moving to the right direction. At zero electric degree, left rotor teeth  41 L are at positions between each two left stator teeth  21 L. Each N-pole area  6 N just faces left teeth  21 L. At 90 electric degrees, the Ul-phase current I 1  is supplied to Ul-phase winding  3 U 1 . Teeth  21 L attract the left teeth  41 L and repulse N-pole areas  6 N because top surfaces of the left teeth  41 L are magnetized to N-poles. At 180 electric degrees, the left rotor teeth  41 L face the next left teeth  21 L. Then, U 1 -phase current I 1  is stopped. The other rotor cores  4 U 2 - 2 W 2  move rotor core  4 U 1  to the right direction. The left teeth  41 L reach at a position of zero electric degree. A total torque of the TFPMSRM is increased because the TFPMSRM produces both of the attracting torque of the rotor teeth  41 L, which is the switched reluctance motor torque, and the repulsion magnet torque of N-pole areas  6 N, which is the permanent magnet torque, during the period from zero electric degrees to 180 electric degrees in the motor operation. 
         [0131]    It is important that a copper loss and an iron loss of the TFPMSRM are reduced relatively because the permanent magnet torque is generated without extending the current-supplying period. Furthermore, the TFPMSRM does not need to increase the sizes because the permanent magnet layer  6  is disposed in the space among the rotor teeth  41 L,  41 R. 
         [0132]      FIG. 52  is a reference side view for showing a motor-operation of an AC-driven TFPMSRM or AC-driven TFSynRM with a permanent magnet layer  6 . The stator and the rotor shown in  FIG. 52  are same as the stator and the rotor shown in  FIG. 51 .  FIG. 52  shows four positions of left rotor teeth  41 L of rotor core  4 U 1  moving to the right direction. The torque pattern of the left teeth  41 L shown in  FIG. 52  is the same as the torque pattern of the left teeth  41 L shown in  FIG. 51  in a period from 0 electric degrees to 180 electric degrees. However, the torque of the left teeth  41 L shown in  FIG. 52  is different from the torque of the left teeth  41 L shown in  FIG. 51  in a period from 180 electric degrees to zero electric degree. For example, at 270 electric degrees, the left stator teeth  21 L shown in  FIG. 52  become S-pole, because the AC phase current I 1  flows to the reverse direction. Thus, left stator teeth  21 L attract both of N-pole areas  6 N and the left rotor teeth  41 L. The attracting torque Tr of the left rotor teeth  41 L is the braking torque. After all, the ratio of torque / current is not increased much, when the large AC current is supplied, but the copper loss and the iron loss are increased because the current-supplying period is extended. Moreover, the AC-driving method needs an inverter, which needs more switching elements in comparison with a DC-driven asymmetrical power converter. 
       The Fifth Embodiment 
       [0133]    The fifth embodiment for disclosing the CTFM with the circumferential tandem structure is explained referring to  FIGS. 53-54 .  FIG. 53  is an axial cross-section showing a three-phase TFIM with circumferential tandem structure.  FIG. 54  shows a schematic side view of the three-phase TFIM shown in  FIG. 53 . Two sets of three stator cores  2 U,  2 V and  2 W are arranged to the circumferential direction in turn. Each of the six stator cores has essentially arc-shape of 60 degrees each. 
         [0134]    In  FIG. 53 , stator  1  has stator cores  2 A and  2 B arranged axially in tandem. Two arc-shaped portions of one U-phase winding  3 U are accommodated in arc-shaped slots of stator cores  2 A and  2 B respectively. Stator housing  100  having a bowl-shaped front housing  101  and a bowl-shaped rear housing  102  accommodates teeth-holder  1   a,  stator core  2 A, teeth-holder  1   b  and  1   c,  stator core  2 B and teeth-holder  1   d  in turn in the axial direction. Rotor  4  has ring-shaped rotor cores  4 A and  4 B arranged axially in tandem. Copper cylinder  200 A constituting the squirrel-cage secondary winding is fixed on rotor housing  200  fixed to rotor shaft  201 . 
         [0135]    As shown in  FIG. 54 , the two sets of arc-shaped stator cores  2 U,  2 V and  2 W are arranged to the circumferential direction PH in turn. However, two sets of stator cores  2 U,  2 V and  2 W have a ring-shaped common yoke portion  24 . In other words, stator teeth  21 L and  21 R and diagonal portions  25 L and  25 R of stator core  2 A belong to the two sets of stator cores  2 U,  2 V and  2 W. Similarly, stator teeth  21 L and  21 R and diagonal portions  25 L and  25 R of stator core  2 B belong to the two sets of stator core portions  2 U,  2 V and  2 W. Each of arc-shaped phase windings  3 U,  3 V and  3 W has mostly 60 degrees. U-phase winding  3 U is wound on adjacent two stator core portions  2 U. V-phase winding  3 V is wound on adjacent two stator core portions  2 V. W-phase winding  3 W is wound on adjacent two stator core portions  2 W. 
         [0136]      FIG. 55  is an axial cross-section for showing stator cores  2 A and  2 B and teeth holders  1   a,    1   b,    1   c  and  1   d.  The stator cores  2 A and  2 B and teeth holders  1   a,    1   b,    1   c  and  1   d  are separated to each other to the axial direction (AX). The teeth holders  1   a,    1   b,    1   c  and  1   d  are non-ferromagnetic members for holding diagonal portions  25 L and  25 R and teeth  21 L and  21 R.  FIG. 56  is a partial side view showing stator core  2 A. Teeth holders  1   a,    1   b,    1   c  and  1   d  are made from aluminum. Each of teeth-holders  1   a - 1   d  has a ring portion (a longitudinal portion)  10   a  and salient  10 T projecting inward from the ring portion  10   a.  Each salient  10 T of teeth holders  1   a  and  1   c  projects into a space between each two left teeth  21 L and  21 L, which are adjacent to each other in the circumferential direction PH. Each salient  10 T of teeth holders  1   b  and  1   d  projects into a space between each two right teeth  21 R and  21 R, which are adjacent to each other in the circumferential direction PH. A number of salient  10 T of each of teeth-holders  1   a - 1   d  is equal to a number of either left teeth  21 L of stator core  2 A. An inner diagonal surface  10   d  of the ring portion  10   a  come into contact with outer diagonal surfaces  25   a  of the diagonal portions  25 L and  25 R. According to  FIG. 55 , each circumferential side surface of stator teeth  21 L and  21 R has each fitting portion consisting of each concave portion  29 A extending to axial direction AX. 
         [0137]    According to  FIG. 55 , each circumferential side surface of salient  10 T of teeth holders  1   a - 1   d  has each fitting portion consisting of each convex portion  19  extending to axial direction AX. Each of the convex portions  19  projecting to the circumferential direction PH is fitted into each of the concave portions  29 A. In other words, each convex portion  19  and each concave portion  29 A are joined to each other. As shown in  FIG. 56 , the fitting portions positioned at one side of teeth  21 L and  21 R in the circumferential direction consist of concave portions  29 A, and the the fitting portions positioned at the other side of teeth  21 L and  21 R in the circumferential direction consist of convex portions  29 B. Accordingly, the fitting portions of each teeth holders  1   a - 1   d  consist of the convex portions  19  fitting to the concave portions  29 A of teeth  21 L and  21 R and the concave portions fitting to the convex portions  29 B of teeth  21 L and  21 R. After all, the fitting portions of teeth holders  1   a - 1   d  and teeth  21 L and  21 R fitted to each other prohibit extension and shortening of teeth  21 L and  21 R in the radial direction RA. Vibrations of stator teeth  21 L and  21 R are restrained because salient  10 T extending from ring portion  10   a  of teeth-holders  1   a - 1   d  supports stator teeth  21 L and  21 R. 
         [0138]      FIG. 57  is a partial development of showing side surfaces of stator core  2 A and rotor core  4 A near end portions of U-phase winding  3 U and V-phase winding  3 V, which are adjacent to each other in the circumferential direction PH. Each of stator cores  2 A and  2 B has wide end-slots  2000 A by means of abbreviating stator teeth  21 L and  21 R. A coil-end portion  300 U of U-phase winding  3 U and a coil-end portion  300 V of V-phase winding  3 V are accommodated in the end-slots  2000 A as shown in  FIG. 57 . 
         [0139]      FIG. 58  is an axial cross-section showing stator core  2 A with U-phase winding  3 U. Arc-shaped or ring-shaped winding  3 U made of a copper tape  310  covered by an insulation layer is wound helically and accommodated in a ring-shaped slot of stator core  2 A. Both of end portions of copper tape  310  as the thin copper plates extends outward after the bending. Copper tape  310  laminated helically achieves the high packing density, the excellent radiation capability and the low skin effect. Moreover, copper tape  310  wound helically can be accommodated easily in a ring-shaped slot of stator core  2 A because an diameter of helical copper tape  310  is reduced by means of increasing a turn number of copper tape  310 . After all, the stator winding  3 U is capable of having a high ratio of the current density and a low copper loss in comparison with a conventional round-shaped conductor line. It means to realize a compact machine. 
         [0140]      FIG. 59  is a circumferential development of stator cores  2 A and  2 B with two windings  3 U and  3 V shown in  FIG. 57 .  FIG. 60  is an arranged circumferential development of two windings  3 U and  3 V. The coil end  300  of U-phase winding  3 U has an inner portion  3 Ua, a middle portion  3 Ub and an outer portion  3 Uc. The coil end  300  of V-phase winding  3 U has an inner portion  3 Va, a middle portion  3 Vb and an outer portion  3 Vc. The divided three portions of coil end  300  are wound through different spaces between adjacent two teeth  21 L and  21 R respectively as shown in  FIG. 60 . Therefore, end-slots  2000 A are shortened. 
         [0141]    Another arrangement of the stator cores is shown in  FIG. 61 .  FIG. 61  is a schematic side view of a dual-three-phase TFIMs with the circumferential tandem structure. Stator cores  2 A and  2 B with the circumferential tandem structure have six stator cores  2 U 1 ,  2 W 2 ,  2 V 1 ,  2 U 2 ,  2 W 1  and  2 V 2  arranged to the circumferential direction in turn. Each of six phase windings  3 U 1 - 3 W 2  are wound on each of six stator cores  2 U 1 ,  2 W 2 ,  2 V 1 ,  2 U 2 ,  2 W 1  and  2 V 2  respectively. Therefore, the dual-three-phase TFIMs can be driven by a nine-switch shown in a PCT patent application applied by an inventor.  FIG. 62  is a circumferential development showing skewed rotor teeth  41 L and  41 R. 
         [0142]    Additional Explanation 
         [0143]    Other aspects of the invention are explained. A known TFM has a single-phase winding wound in a ring-shape slot or a arc-shaped slot of a stator core. The stator core has left teeth, right teeth and a yoke portion. The yoke portion connects the left teeth to the right teeth magnetically. The single-phase winding extends in a space between the left teeth and the right teeth toward a moving direction (a longitudinal direction) of a moving core. The difference between the CTFM of the present invention and the conventional TFM is on the addition of diagonal portions ( 25 L,  25 R) extending diagonally. The diagonal portions ( 25 L,  25 R) realizes the transverse flux machine having an axially-stacked core or a helical-laminated core. The features explained as below can be employed by a conventional TFM. 
         [0144]      FIG. 10  shows to employ the reluctance mode in order to generating a starting torque of the transverse induction machine (TFIM). This idea can be employed by the other TFIMs having known core structure.  FIGS. 11-13  show two motor-generator sets consisting of the TFIM each. A relay shown in  FIG. 11  connects the two TFIMs in a predetermined condition after supplying a common three-phase voltage to two TFIMs in order to reduce the sparking of the relay. The frequency of the common three-phase voltage is controlled in a range between two synchronous frequencies of the two TFIMs. This idea can be employed by the other TFIMs having known core structure. 
         [0145]      FIGS. 14-27  show three TFWRMs having a rotor circuit including three secondary windings, a rectifier and three field windings. The secondary windings and the field windings are accommodated in a ring-shaped slots of the rotor core. Preferably, three of the secondary windings with the star-connection supply the field current via the three-phase full-bridge diode rectifier to the three field windings connected in series. Furthermore, the primary field windings wound on the stator cores are disclosed. This idea can be employed by the other TFIMs having known core structure. The primary field windings is desirable for the transverse flux generator such as an alternator or a wind turbine generator. 
         [0146]      FIGS. 31-32  show the sequential magnetization process for reducing the circumferential magnetic flux passages.  FIGS. 48-51  show the TFPMSRM capable of generating both of the switched reluctance torque and the magnet torque simultaneously without increasing the power loss. This idea can be employed by the other TFIMs having known core structure.