WO2013008275A1

WO2013008275A1 - Transverse flux machine apparatus

Info

Publication number: WO2013008275A1
Application number: PCT/JP2011/003999
Authority: WO
Inventors: Shouichi Tanaka
Original assignee: Three Eye Co., Ltd.
Priority date: 2011-07-13
Filing date: 2011-07-13
Publication date: 2013-01-17

Abstract

An object of the present invention is to provide a transverse flux machine apparatus having a simple power converter with a high efficiency for driving a switched reluctance motor (SRM). Another object of the invention is to provide a transverse flux machine apparatus having compact structure of a switched reluctance motor with a high torque. The TFM apparatus has a three-phase power converter for the SRM constructed with six MOS transistors and two free-wheeling diodes. A power loss and a production cost of the power converter are reduced largely. A TFSRM has a magnet member having N-pole areas disposed between left rotor teeth and S-pole areas disposed between right rotor teeth. Therefore, A torque is increased. A TFM has two stators and two rotors. Left stator teeth of the first stator and right stator teeth of the second stator are disposed at same axial position. Left rotor teeth of the first rotor and right rotor teeth of the second rotor are disposed at same axial position. Thus a compact TFM is constructed.

Description

TRANSVERSE FLUX MACHINE APPARATUS

Cross-Reference to related application

This application claims benefit under 35 U.S.C.119 of PCT/JP2011/000669 filed on Feb/07/2011, the title of TRANSVERSE FLUX MACHINE, of which the entire content are incorporated herein reference.

Background of Invention

1. Field of the Invention
The present invention relates to a transverse flux machine apparatus (TFMA), in particular to a three-phase transverse flux machine apparatus employing a switched reluctance motor type.

2. Description of the Related Art
A known transverse flux machine (TFM) capable of producing a large torque is strongly expected for direct-drive applications, for example an in-wheel motor, an engine-assisting motor, a wind generator and so on. In TFM technology, it is preferable to employ a plurality of TFMs arranged in tandem for reducing torque ripples, because a TFM is essentially a single-phase motor or a single-phase generator.

However, it is well known that a prior TFM has very complicate structure in comparison with a conventional radial gap motor. United States Patent Ser.No. 4,973,868 discloses a U-shaped cut core made of a wound steel core. United States Patent No. 4,849,871 describes expensive three full-bridge inverters for driving three single-phase TFMs.

A tandem three-phase TFM driven by switched reluctance method is preferable for some applications such as the in-wheel motor, because the switched reluctance multi-phase TFM, called the TFSRM, has very low levels of vibration, acoustic noise and torque ripples in comparison with a conventional radial gap SRM.

However, a prior power converter for driving a prior three-phase SRM or a prior TFSRM is driven by a complicated power converter in comparison with a three-phase inverter for driving a permanent magnet synchronous motor (PM). It is required for the SRM or the TFSRM to realize a simple power converter.

United States Patent No. 4,973,868 United States Patent No. 4,849,871

An object of the invention is to provide a transverse flux machine apparatus (TFMA) having a simple power converter with a high efficiency for driving a switched reluctance motor. Another object of the invention is to provide a compact transverse flux machine apparatus (TFMA) generating a large torque.

According to a first aspect of the invention, a power converter for driving three single-phase switched reluctance motors has three asynchronous half bridges (200U, 200V and 200W) driving three phase windings (3U, 3V and 3W) respectively. Both ends of a V-phase winding (3V) are connected to a U-phase winding (3U) and a W-phase winding (3W) respectively. Accordingly, a power loss of the power converter is reduced.

According to a preferred embodiment, the power converter has four legs (301-304). Two of the four legs (302 and 303) of driving the V-phase winding (3V) consist transistors (T2 -T5) with free-wheeling diodes connected in anti-parallel to each of the transistors (T2-T5).

According to another preferred embodiment, the power converter has two diodes (D1 and D6) and six MOS transistors (T1-T6). Body diodes of the MOS transistors (T1-T6) combine the free-wheeling diodes of the power converter. Accordingly, it is realized to construct the power converter with simple topology, because a conventional power converter for driving three-phase SRM has six transistors and six free-wheeling diodes.

According to another preferred embodiment, three single-phase transverse flux machines have a stator having a stator core made of laminated steel sheets with bent teeth each. Accordingly, the TFM is constructed with laminated steel sheets.

According to another preferred embodiment, the three single-phase transverse flux machines has a rotor (4U) having a rotor core made of laminated steel sheets with bent teeth each. Accordingly, the TFM is constructed with laminated steel sheets.

According to a second aspect of the invention, a TFMA has a rotor (4U) having a magnet member (6). Each of the N-pole areas of the magnet member (6) is disposed between adjacent each two left rotor teeth (41L). Each of the S-pole areas of the magnet member (6) is disposed between adjacent each two right rotor teeth (41R). Accordingly, a torque of the TFMA is increased.

According to a third aspect of the invention, a stator (1U) has a pair of a left stator (11U) and a right stator (12U) being adjacent to each other. Each of the right stator teeth (21R) of the left stator (11U) is disposed between adjacent each two of the left stator teeth (21L) of the right stator (12U). The rotor (4U) has a pair of a left rotor (41U) and a right rotor (42U) being adjacent to each other. Each of the right rotor teeth (41R) of the left rotor (41U) is disposed between adjacent each two of the left rotor teeth (41L) of the right rotor (42U). Accordingly, a compact TFMA generating a large torque is constructed.

Figure 1 is an axial cross-section schematically showing a three-phase TFSRM. Figure 2 is an axial cross-section schematically showing a three stator/rotor pairs of the TFSRM shown in Figure 1. Figure 3 is a schematic view showing of a laminating process of the stator core shown in Figure 4. Figure 4 is an enlarged axial cross-section schematically showing the enlarged stator core shown in Figure 3. Figure 5 is a partial side view of a ring-shaped stator shown in Figure 3. Figure 6 is a partial circumferential development of the ring-shaped stator core shown in Figure 5. Figure 7A is an axial cross-section (line A-A) schematically showing three rotors with magnet rings. Figure 7B is a partial development showing arrangement of rotor teeth and magnet rings. Figure 7C is an axial cross-section (line B-B) schematically showing three rotors with magnet rings. Figure 7 is a schematic side view showing a first relative position of a pair of the stator and the rotor. Figure 9 is a schematic side view showing a second relative position of a pair of the stator and the rotor. Figure 10 is a schematic side view showing a third relative position of a pair of the stator and the rotor. Figure 11 is a schematic cross-section of a U-phase TFM having a pair of stators and a pair of rotors. Figure 12 is a partial development showing stator teeth of two stators. Figure 13 is a partial development showing rotor teeth of two rotors. Figure 14 is a schematic cross-section showing three single-phase TFSRM having six stators and six rotors. Figure 15 is a circuit topology configuration showing a three-phase power converter consisting of three asynchronous half bridges. Figure 16 is a circuit topology configuration showing a three-phase power converter consisting of six MOS transistors and two diodes. Figure 17 is a timing chart showing motor operation of the power circuit shown in Figure 16. Figure 18 is a circuit topology configuration showing currents in a period t1. Figure 19 is a circuit topology configuration showing currents in a period t2. Figure 20 is a circuit topology configuration showing currents in a period t3. Figure 21 is a circuit topology configuration showing currents in a period t4. Figure 22 is a circuit topology configuration showing currents in a period t5. Figure 23 is a circuit topology configuration showing currents in a period t6. Figure 24 is a circuit topology configuration showing currents in a period t7. Figure 25 is a circuit topology configuration showing currents in a period t8. Figure 26 is a circuit topology configuration showing currents in a period t9. Figure 27 is a timing chart showing generator operation of the power circuit shown in Figure 16. Figure 28 is a circuit topology configuration showing currents in a period t1. Figure 29 is a circuit topology configuration showing a current in a period t2. Figure 30 is a circuit topology configuration showing currents in a period t3. Figure 31 is a circuit topology configuration showing a current in a period t4. Figure 32 is a circuit topology configuration showing currents in a period t5. Figure 33 is a circuit topology configuration showing a current in a period t6.

Detailed Description of the Preferred Embodiments

A preferred embodiment about three-phase transverse flux machine apparatus (a three-phase TFMA) is explained referring to drawings. The TFMA consists of three single-phase TFMs and a three-phase power converter for driving three single-phase TFMs.

Figure 1 is an axial cross-section schematically showing a three-phase TFM consisting of three single-phase transverse flux switched reluctance motors, which is called a three-phase TFSRM 1. The TFSRM 1 has a housing, three single-phase TFSRMs and a rotor disk 9 press-fixed to a revolving axis 10. The TFSRMs consists of a U-phase TFSRM, a V-phase TFSRM and a W-phase TFSRM. The U-phase TFSRM has a pair of a U-phase stator 1U and a U-phase rotor 4U. The V-phase TFSRM has a pair of a V-phase stator 1V and a V-phase rotor 4V. The W-phase TFSRM has a pair of a W-phase stator 1W and a W-phase rotor 4W.

The housing 1 consists of a bowl-shaped front housing 11, center rings 12 and 13 and a rear disk 14, which are made from aluminum alloy. The center rings 12 and 13 are press-fixed on an inner circumferential surface of a cylinder portion of the front housing 11. The rear disk 14 is press-fixed on an inner circumferential surface of the cylinder portion 1 of the front housing 11. The rear disk 14 closes an opening of front housing 11. The front housing 11 and rear disk 14 support the axis 10. The U-phase stator 1U is sandwiched by front housing 11 and center ring 12. The V-phase stator 1V is sandwiched by center rings 12 and 13. The W-phase stator 1W is sandwiched by center ring 13 and end disk 14.

The rotor disk 9 consists of a front ring 91,

center disks

92 and 93 and a rear ring 94, which are made from aluminum alloy. The

center disks

92 and 93 are press-fixed on an outer circumferential surface of the axis 10. The U-phase rotor 4U is sandwiched by the front ring 91 and the center disk 92. The V-phase rotor 4V is sandwiched by the

center disks

92 and 93. The W-phase rotor 4W is sandwiched by center disk 93 and rear ring 94. The above sandwiching operation is executed to an axial direction of axis 10.

Stators 1U, 1V and 1W and

rotors

4U, 4V and 4W are explained referring to Figure 2. Figure 2 is an axial cross-section showing the three single-phase TFSRMs. Three stators 1U, 1V and 1W are adjacent to each other to the axial direction AX. Three

rotors

4U, 4V and 4W are adjacent to each other to the axial direction AX.

Stator 1U has a ring-shaped U-phase stator core 2U and a ring-shaped U-phase winding 3U. V-phase stator 1V has a ring-shaped V-phase stator core 2V and a ring-shaped V-phase winding 3V. W-phase stator 1W has a ring-shaped W-phase stator core 2W and a ring-shaped W-phase winding 3W.

Each of

stator cores

2U, 2V and 2W consists of a laminated steel core having left stator teeth 21L, right stator teeth, a ring-shaped yoke portion 24, left diagonal portions 25L and right diagonal portions 25R. The

stator teeth

21L and 21R project radial inward. Three ring-shaped yoke portions 24 extend to the circumferential direction. The left stator teeth 21L are arranged to the circumferential direction. The right stator teeth 21R are arranged to the circumferential direction. The left diagonal portions 25L are arranged to the circumferential direction. The right diagonal portions 25R are arranged to the circumferential direction. Each left diagonal portion 25L joins each left stator tooth 21L and yoke portion 24. Each right diagonal portion 25R joins each right stator tooth 21R and yoke portion 24.

Left diagonal portions 25L extend diagonally from yoke portion 24 forward and radial inward. Right diagonal portions 25R extend diagonally from yoke portion 24 backward and radial inward. Left stator teeth 21L and right stator teeth 21R of U-phase stator core 2U are adjacent to each other in the axial direction AX across the ring-shaped U-phase winding 3U. Left stator teeth 21L and right stator teeth 21R of V-phase stator core 2V are adjacent to each other in the axial direction AX across the ring-shaped V-phase winding 3V. Left stator teeth 21L and right stator teeth 21R of W-phase stator core 2W are adjacent to each other in the axial direction AX across the ring-shaped W-phase winding 3W.

Three

rotors

4U, 4V and 4W are adjacent to each other to the axial direction AX. Each of

rotors

4U, 4V and 4W has a laminated core having left rotor teeth 41L, right rotor teeth 41R, a ring-shaped yoke portion 44, left diagonal portions 45L and right diagonal portions 45R. The

rotor teeth

41L and 41R project radial outward. Each yoke portion 44 extends to the circumferential direction.

Left rotor teeth 41L are arranged to the circumferential direction. Right rotor teeth 41R are arranged to the circumferential direction. Left diagonal portions 45L are arranged to the circumferential direction. Right diagonal portions 45R are arranged to the circumferential direction. Each left diagonal portion 45L joins each left rotor tooth 41L and yoke portion 44. Each right diagonal portion 45R joins each right rotor tooth 41R and yoke portion 44. Left diagonal portions 45L extend diagonally from yoke portion 44 toward forward and radial outward. Right diagonal portions 45R extend diagonally from yoke portion 44 backward and radial outward.

Left rotor teeth 41L and right rotor teeth 41R of U-phase rotor 4U are adjacent to each other in the axial direction AX across a magnet ring 6. Left rotor teeth 41L and right rotor teeth 41R of V-phase rotor 4V are adjacent to each other in the axial direction AX across another magnet ring 6. Left rotor teeth 41L and right rotor teeth 41R of W-phase rotor core 4W are adjacent to each other in the axial direction AX across another magnet ring 6.

Left rotor teeth 41L are capable of facing left stator teeth 21L across a ring-shaped small air gap 'g'. Right rotor teeth 41R are capable of facing right stator teeth 21R across the ring-shaped small air 'g'.

Stator cores

2U, 2V, 2W and rotor cores of

rotors

4U, 4V and 4W are made of a plurality of ring-plate-shaped soft steel sheets 7 laminated to the axial direction AX as shown in Figures 3. Instead of the laminating, it is capable of employing a spirally wound soft steel tape.

Figure 3 shows the laminating operation of ring-shaped soft steel sheets 7. Each of soft steel sheets 7 consists of left teeth 71L, right teeth 71R, a ring-shaped yoke portion 74, and left diagonal portions 75L and right diagonal portions 75R. The left teeth 71L and the right teeth 71R project radially inward. The yoke portion 74 extends to the circumferential direction. The left diagonal portions 75L extending diagonally joins left teeth 71L and yoke portion 74.

Each of the right diagonal portions 75R extending diagonally joins right teeth 71R and yoke portion 74. Consequently, each of

stator cores

2U, 2V and 2W is constructed with a predetermined number of the laminated soft steel sheets 7. Similarly, each of

rotor cores

4U, 4V and 4W is constructed by predetermined number of laminated soft steel plates. Left diagonal portions 75L and right diagonal portions 75R are formed by means of bending a flat steel plate.

Figure 4 is an enlarged cross-section, which schematically shows U-phase stator 1U with ring-shaped stator core 2U and ring-shaped U-phase winding 3U. It is considered that each ring-shaped gap 74g is formed between each pair of yoke portions 74 being adjacent to each other in the axial direction AX. Similarly, each teeth-shaped gap 71g is formed between each pair of left teeth 71L being adjacent to each other in the axial direction AX. Furthermore, each teeth-shaped gap 71g is formed between each pair of right teeth 71R being adjacent to each other in the axial direction AX, too.

The gaps 74g and 71g can be buried with resin material or resin film. The resin film can include soft iron powder. Yoke portions 74 and teeth 71L and 71R can be curved in the axial direction in order to reduce axial vibration of yoke portions 74 and teeth 71L and 71R.

Figure 5 is a partial side view of U-phase stator 1U. Figure 6 partially shows a circumferential development of the ring-shaped U-phase stator core 2U. Left stator teeth 21L are arranged to the circumferential direction. Right stator teeth 21R are arranged to the circumferential direction. Two of the left stator teeth 21L are adjacent to each other across one non-magnetic spacer 8.

The left diagonal portions 25L are arranged to the circumferential direction PH. The right diagonal portions 25R are arranged to the circumferential direction. In Figure 5, left stator teeth 21L and left diagonal portions 25L are illustrated, but right stator teeth 21R and right diagonal portions 25R are hidden by non-magnetic spacers 8 disposed between right stator teeth 21R and right diagonal portions 25R, which are adjacent to each other in the circumferential direction. The non-magnetic spacers 8 are formed by molding resin material or non-magnetic metal.

Left diagonal portion 25L and right diagonal portion 25R are arranged alternately in the circumferential direction PH. The

rotor

4U, 4V and 4W are made with the same method explained above. Similarly, U-phase rotor core 4U, V-phase rotor core 4V and W-phase rotor core 4W are constructed with the same method for constructing the three-phase stators 1U, 1V and 1W.

In the other words, ring-shaped non-magnetic spacers 8 are inserted in spaces between each of adjacent two

diagonal portions

25L and 25L, 25R and 25R, 21L and 21L and 21R and 21R. Spacers 8 are formed with aluminum alloy. Spacers 8 are projected from the front housing 11, center rings 12 and 13 and rear disk 14 to the axial direction.

Figure 7A is a schematic cross-section (A-A) partially showing

rotors

4U, 4V and 4W in the axial direction AX. Figure 7B is a schematic development of an outer surface of

rotor

4U, 4V and 4W in the circumferential direction PH. Figures 7C is a cross-section (B-B) partially showing

rotors

4U, 4V and 4W in the axial direction AX. An outer surface of the magnet rings 8 made of a permanent magnet each has N-pole areas and S-pole areas. The S-pole areas are disposed among left rotor teeth 41L of rotor 4U, among right rotor teeth 41R of rotor 4V and among left rotor teeth 41L of rotor 4W. The N-pole areas are disposed among right rotor teeth 41R of rotor 4U, among left rotor teeth 41L of rotor 4V and among right rotor teeth 41L of rotor 4W.

Motor operation of U-phase single-phase TFM is explained referring to Figures 8-10. Figure 8 shows a stable position of rotor 4U. Each left stator teeth 21L stops just upon each S-pole area among each left rotor teeth 41L. Rotor 4U moves to the left direction, when U-phase current IU is supplied to U-phase winding 4U as shown in Figure 9, because the rotor is moving to the left direction by the V-phase TFM and the W-phase TFM. Left stator teeth 21L pull left rotor teeth 41L. Moreover, Left stator teeth 21L push S-pole areas of magnet ring 6.U-phase rotor 4U moves to the left direction.

U-phase current Iu is stopped before left rotor teeth 41L reach just under left stator teeth 21L as shown in Figure 10. However, permanent magnet forces between S-pole areas and left stator poles 21L pulls S-pole areas to the left direction. Accordingly, the U-phase single-phase TFSRM having magnet ring 6 has an increased torque and a reduced torque ripples.

According to an arranged embodiment, the current direction of U-phase current Iu is changed, after left rotor teeth 41L has reached just under left stator teeth 21L as shown in Figure 10. Left stator teeth 21L magnetized to N-poles pull left rotor teeth 41L. This is essentially same as known operation of a permanent magnet synchronous motor (PM) having a reluctance torque. After all, the above tandem TFM with magnet ring 6 is capable to be driven by a well-known three-phase inverter, too.

Another arranged embodiment is explained referring to Figures 11-13. In Figure 11-13, U-phase TFSRM consists of a left U-phase TFSRM and a right U-phase TFSRM. The left TFSRM consists of a left stator 11U and a left rotor 41U. The right TFSRM consists of a right stator 12U and a right rotor 42U. Stator 1U consists of the left stator 11U and the right stator 12U. Rotor 4U consists of the left rotor 41U and the right rotor 42U.

Two stators 11U and 12U are adjacent to each other in the axial direction AX, and two rotors 41U and 42U are adjacent to each other in the axial direction AX, too. Stator 11U consists of a ring-shaped U-phase stator core 2U and a ring-shaped U-phase winding 31U. Stator 12U consists of a ring-shaped U-phase stator core 2U and a ring-shaped U-phase winding 32U. Each of U-phase windings 31U and 32U is essentially same as U-phase winding 3U shown in Figure 2 each. Each of rotors 41U and 42U is essentially same as U-phase rotor 4U shown in Figure 2.

It is important that each of right teeth 21R (not illustrated in Figure 11) of left stator 11U is disposed between each pair of adjacent left teeth 21L of right stator 12U. Each of non-magnetic spacers 80 is disposed between each of right teeth 21R of left stator 11U and each of left teeth 21L of right stator 12U as shown in Figure 12. Figure 12 is a partial development showing

stator teeth

21L and 21R of U-phase stators 11U and 12U. In Figure 12, A bent line 1001 schematically shows a flux path of stator 11U. Similarly, a bent line 1002 schematically shows a flux path of stator 12U. In Figure 12, it is capable that U-phase windings 31U and 32U have opposite current directions to each other.

Figure 13 is a partial development showing

rotor teeth

41L and 41R of U-phase rotors 41U and 42U.

Rotor teeth

41L and 41R of left rotor 41U are just under

stator teeth

21L and 21R of left stator 11U, when

rotor teeth

41L and 41R of right rotor 42U are just under

stator teeth

21L and 21R of right stator 12U. Similarly,

rotor teeth

41L and 41R of left rotor 41U are between

stator teeth

21L and 21R of left stator 11U, when

rotor teeth

41L and 41R of right rotor 42U are between

stator teeth

21L and 21R of right stator 12U.

As the result, a compact TFSRM is constructed. The smallest value of the inductance including a leakage inductance of U-phase windings 31U and 32U are not large. The TFSRM is shown in Figures 11-13. However, technical philosophy based on the overlapped dual stator/rotor pairs with the same phase is employed by the other TFM including a conventional TFM. For example, a single-phase PM TFM or single-phase induction TFM is enabled to employ the above overlapped dual stator/rotor structure. Figure 14 shows a three-phase TFSRM having six single-phase TFSRMs. The three-phase TFSRM generating a strong torque has a compact axial width.

Preferably, the above three single-phase TFSRMs are driven by a three-phase power converter shown in Figure 15. Figure 15 is a circuit topology configuration of three-phase power converter 200 for driving the three-phase TFSRM shown in Figures 1-14. The power converter 200 consists of three asynchronous half-bridges 200U, 200V and 200W. The U-phase asynchronous half-bridge 200U for driving U-phase winding 3U consists of diodes D1 and D2 and MOS transistors T1 and T2. The V-phase asynchronous half-bridge 200V for driving V-phase winding 3V consists of diodes D3 and D4 and MOS transistors T3 and T4. The W-phase asynchronous half-bridge 200W for driving W-phase winding 3W consists of diodes D5 and D6 and MOS transistors T5 and T6.

Half-bridges 200U, 200V and 200W are same as well-known conventional asynchronous half-bridges for driving a conventional three-phase SRM. However, Power converter 200 further has two connecting

lines

211 and 212. The connecting line 211 directly connection one end of U-phase winding 3U and one end of V-phase winding 3V. The connection line 212 directly connects one end of V-phase winding 3V and one end of W-phase winding 3W.

Connection lines

211 and 212 reduce a power loss of power converter 200 as described later.

Figure 16 is a circuit topology configuration of three-phase power converter 300 for driving the three-phase TFSRM, for example shown in Figures 1-14. The power converter 300 is essentially same as power converter 200 shown in Figure 15.

In the other words, a body diode of MOS transistor T2 combines the free-wheeling diode D3, which is connected in parallel to the body diode of MOS transistor T2. A body diode of MOS transistor T3 combines the free-wheeling diode D2, which is connected in parallel to the body diode of MOS transistor T3. Furthermore, a body diode of MOS transistor T4 combines the free-wheeling diode D5, which is connected in parallel to the body diode of MOS transistor T4. A body diode of MOS transistor T5 combines the free-wheeling diode D4, which is connected in parallel to the body diode of MOS transistor T5.

However, the other end N of U-phase winding 3U is not connected to the other end of W-phase winding 3W in order to stop a circulating current circulating around three-

windings

3U, 3V and 3W. It is capable to employing any transistor, for example an IGBT instead of the above MOS transistor, if a free-wheeling diode is connected in anti-parallel to the IGBT. After all, the power converter 300 saves semiconductor elements and a production cost, because converter only employs two free-wheeling diodes and six transistors with diodes. It is enable to employ the

power converters

200 and 300 for driving a known conventional three-phase SRM, too.

Motor operation of three single-phase TFSRMs shown in Figure 1 is explained hereinafter referring to Figures 17-26. Generally, a motor operation of a power converter for operating a SRM has two types. One type is PWM operation type, and another type is one-pulse operation type. For example, the PWM operation type is explained in Figures 17-26.

Figure 17 is a timing chart showing inductances LU, LV and LW and phase currents IU, IV and IW of three

phase windings

3U, 3V and 3W. Each inductance increases in each increasing period Ti. Each inductance decreases in each decreasing period Td. The inductances LU, LV and LW keep a peak level in each peak period Tp each. Inductances LU, LV and LW keep a bottom level in each bottom period Tb each.

Each of phase currents IU, IV and IW is increased in a current-increasing period Tx, keeps constant in a constant current period Ty, is decreased in a current-decreasing period Tz, and becomes zero in an absent period Tab. A revolving angle of 360 electrical degrees is divided to periods t1-t9 as shown in Figure 17.

Figure 18 shows the period t1. Transistors T1, T3 and T4 are turned on. A U-phase magnetizing current IUS flows through inductance LU of U-phase winding 3U. Moreover, a V-phase recovery current IVr returns to a power source (not shown). It is important that directions of currents IUS and IVr are opposite to each other in transistor T3. In the other words, a part of current IUS directly flows through inductance LV without flowing through transistor T3. It causes to decrease the power loss of transistor T3.

Figure 19 shows the next period t2 while transistor T1 is PWM-switched. When transistor T1 is turned off, a U-phase free-wheeling current IUf circulates through diode D1, winding 3U and transistor T3. It is considered that directions of currents IUf and IVr are opposite to each other in transistor T3. It causes to decrease the power loss of switching element T3.

Figure 20 shows the next period t3. The residual magnetic energy of inductance LV becomes zero, and transistor T4 is turned off. The PWM-switching of transistor T1 is continued in order to control amplitude of U-phase current IU including currents IUS and IUf.

Figure 21 shows the next period t4. Transistors T2, T4 and T6 are turned on. A W-phase magnetizing current IWS flows through inductance LW of W-phase winding 3W. Moreover, a U-phase recovery current IUr returns to the power source. It is important that a current does not flow through the inductance Lv, because potentials of connecting points C1 and C2 are essentially equal to each other. Accordingly, V-phase winding 3V are not energized.

Figure 22 shows the next period t5 while transistor T6 is PWM-switched. When transistor T6 is turned off, a W-phase free-wheeling current IWf circulates through diode D6, winding 3W and transistor T4. It is considered that a current does not flow through the inductance Lv by employing the PWM-switching of transitory T6, because potentials of the connecting points C1 and C2 are essentially equal to each other.

Figure 23 shows the next period t6. The residual magnetic energy of inductance LU becomes zero, and transistor T2 is turned off. The PWM-switching of transistor T6 is continued in order to control amplitude of W-phase current IW including currents IWS and IWf.

Figure 24 shows the next period t7. Transistors T2 and T5 are turned on. A V-phase magnetizing current IVS flows through inductance LV of V-phase winding 3V. Moreover, a W-phase recovery current IWr returns to the power source. It is important that directions of currents IVS and IWr are opposite to each other in transistor T5. In the other words, a part of current IVS directly flows through inductance LW without flowing through transistor T5. It causes to decrease the power loss of transistor T5.

Figure 25 shows the next period t8 while transistors T2 and T3 are PWM-switched. When transistor T2 is turned off, and transistor T3 is turned on, a V-phase free-wheeling current IVf circulates through inductance LV and transistor T3 and T5. It is considered that directions of currents IVf and IWr are opposite to each other in transistor T5. It causes to decrease the power loss of switching element T5.

Figure 26 shows the next period t9. The residual magnetic energy of inductance LW becomes zero. The PWM-switching of transistors T2 and T3 are continued in order to control amplitude of V-phase current IV including currents IVS and IVf. It is well-known that a dead time is provided between turning-on periods of transistor T2 and turning-on periods of transistor T3.

Generator operation of three single-phase TFSRMs shown in Figure 1 is explained hereinafter referring to Figures 27-33. Generally, a generator operation of a power converter for operating a SRM has two types. One type is PWM operation, and another type is one-pulse operation. For example. the one-pulse operation is explained in Figures 27-33.

Figure 27 is a timing chart of inductances LU, LV and LW and phase currents IU, IV and IW of three

phase windings

3U, 3V and 3W. Phase currents IU, IV and IW are increased in current-increasing periods t1, t3 and t5 respectively in order to energize winding 3U, 3V and 3W respectively.

Figure 28 shows the period t1. Transistors T1, T3 and T4 are turned on. A U-phase magnetizing current IUS flows through inductance LU of U-phase winding 3U. Moreover, a V-phase recovery current IVr, which is a generating current, is supplied to the power source. It is important that directions of currents IUS and IVr are opposite to each other in transistor T3. It causes to decrease the power loss of transistor T3.

Figure 29 shows the next period t2 after transistor T4 is turned off, because the generating current IVr becomes zero. Furthermore, a U-phase generating current IUr is supplied to the power source, because transistors T1 and T3 are turned off, and transistor T2 is turned on.

Figure 30 shows the next period t3. Transistors T4 and T6 are turned on. A W-phase magnetizing current IWS flows through inductance LW of W-phase winding 3W. Moreover, the U-phase generating current IUr is supplied to the power source. It is important that a current does not flow through the inductance Lv, because potentials of connecting points C1 and C2 are essentially equal to each other.

Figure 31 shows the next period t4. Transistors T2 is turned off, because generating current becomes zero. Moreover, a W-phase generating current IWr is supplied to the power source, because transistors T4 and T6 are turned off and transistor T5 is turned on.

Figure 32 shows the next period t5. Transistors T2 and T5 are turned on. A V-phase magnetizing current IVS flows through inductance LV of V-phase winding 3V. Moreover, a W-phase generating current IWr is supplied to the power source. It is important that directions of currents IVS and IWr are opposite to each other in transistor T5. It causes to decrease the power loss of transistor T5.

Figure 33 shows the next period t6 after transistor T5 is turned off, because the generating current IWr becomes zero. Furthermore, a V-phase generating current IVr is supplied to the power source, because transistors T2 and T5 are turned off, and transistors T3 and T4 are turned on. After all, power converter 300 with six MOS transistors and two diodes is capable of realizing simple structure and a high efficiency. The operations of three-

phase power converters

200 and 300 are enable to be employed by the other known three-phase SRM or the other known three-phase TFSRM, too.

Another arrangement of the three-phase TFM is explained. The TFSRM shown in Figures 7A, 7B, 7C, 8-10 has rotor magnets. Accordingly, the TFSRM can be driven as a synchronous permanent magnet motor (PM). Any skilled engineer can understand that the motor shown in 7A, 7B, 7C, 8-10 is operated as the three-phase PM by means of applying a three-phase voltage to three

phase windings

3U, 3V and 3W.

Claims

A transverse flux machine apparatus comprising a three-phase power converter for respectively applying three phase voltages to three phase windings of three single-phase transverse flux machines arranged in tandem, wherein:
the three single-phase transverse flux machines consist of a switched reluctance motor each;
the three-phase power converter has an U-phase asynchronous half bridge (200U) for driving the U-phase winding (3U), a V-phase asynchronous half bridge (200V) for driving the V-phase winding (3V) and a W-phase asynchronous half bridge (200W) for driving the W-phase winding (3W);
one end of U-phase winding (3U) is directly connected to one end of V-phase winding (3V); and
the other end of V-phase winding (3V) is directly connected to one end of W-phase winding (3W).
The three-phase transverse flux machine apparatus according to claim 1, wherein:
the U-phase winding (3U) is driven by a first leg (301) and a second leg (302) of the power converter (300);
the V-phase winding (3V) is driven by the second leg (302) and a third leg (303) of the power converter (300);
the W-phase winding (3W) is driven by the third leg (303) and a fourth leg (304) of the power converter (300);
the first leg (301) has at least free-wheeling diode (D1) and a transistor (T1) connected in series;
the second leg (302) has transistors (T2 and T3) connected in series;
the third leg (303) has transistors (T4 and T5) connected in series;
the fourth leg (304) has a transistor (T6) and at least free-wheeling diode (D6) connected in series; and
each of free-wheeling diodes is connected in anti-parallel to each of the transistors (T1, T2, T3, T4, T5 and T6).
The three-phase transverse flux machine apparatus according to claim 2, wherein the transistors (T1, T2, T3, T4, T5 and T6) have a MOS transistor with a body diode performing as the free-wheeling diode each.
The three-phase transverse flux machine apparatus according to claim 1, wherein:
each of the three single-phase transverse flux machines has
a pair of a rotor (4U) and a stator (1U) having a stator core (2U) and the winding (3U) wound on the stator core (2U);
the stator core (2U) has left stator teeth (21L), right stator teeth (21R), left diagonal portions (25L), right diagonal portions (25R) and a yoke portion (24);
the left diagonal portions (25L) extending diagonally join the left stator teeth (21L) and the yoke portion (24);
the right diagonal portions (25R) extending diagonally join the right stator teeth (21R) and the yoke portion (24);
the winding (3U) is accommodated between the left stator teeth (21L) and the right stator teeth (21R); and
the stator core (2U) is essentially made of laminated soft steel sheets.
The three-phase transverse flux machine apparatus according to claim 4, wherein:
the rotor (4U) has left rotor teeth (41L), right rotor teeth (41R), left diagonal portions (45L), right diagonal portions (45R) and a yoke portion (44);
the left diagonal portions (45L) extending diagonally join the left rotor teeth (41L) and the yoke portion (44);
the right diagonal portions (45R) extending diagonally join the right rotor teeth (41R) and the yoke portion (44); and
the rotor core (4U) is essentially made of laminated soft steel sheets.
The three-phase transverse flux machine apparatus according to claim 5, wherein:
the rotor (4U) has a magnet member (6) having a permanent magnet;
the magnet member (6) has N-pole areas and S-pole areas;
each of the N-pole areas is disposed between adjacent each two left rotor teeth (41L); and
each of the S-pole areas is disposed between adjacent each two right rotor teeth (41R).
The three-phase transverse flux machine apparatus according to claim 4, wherein:
the stator (1U) has a pair of a left stator (11U) and a right stator (12U) being adjacent to each other;
each of the right stator teeth (21R) of the left stator (11U) is disposed between adjacent each two of the left stator teeth (21L) of the right stator (12U);
the rotor (4U) has a pair of a left rotor (41U) and a right rotor (42U) being adjacent to each other; and
each of the right rotor teeth (41R) of the left rotor (41U) is disposed between adjacent each two of the left rotor teeth (41L) of the right rotor (42U).
A transverse flux machine apparatus comprising a stator (1U) and a rotor (4U), the stator (1U) having a stator core (2U) and a stator winding (3U) wound on the stator core (2U), wherein:
the stator core (2U) has left stator teeth (21L), right stator teeth (21R) and a yoke portion (24) connecting the left stator teeth (21L) and the right stator teeth (21R);
the winding (3U) is accommodated between the left stator teeth (21L) and the right stator teeth (21R);
the rotor (4U) has left rotor teeth (41L), right rotor teeth (41R) and a yoke portion (44) connecting the left rotor teeth (41L) and the right rotor teeth (41R);
the rotor (4U) has a magnet member (6) having a permanent magnet;
the magnet member (6) has N-pole areas and S-pole areas;
each of the N-pole areas is disposed between adjacent each two of the left rotor teeth (41L); and
each of the S-pole areas is disposed between adjacent each two of the right rotor teeth (41R).
The transverse flux machine apparatus according to claim 8, wherein:
the rotor core (4U) has left rotor teeth (41L), right rotor teeth (41R), left diagonal portions (45L), right diagonal portions (45R) and a yoke portion (44);
the left diagonal portions (45L) extending diagonally joins the left rotor teeth (41L) and the yoke portion (44);
the right diagonal portions (45R) extending diagonally joins the right rotor teeth (41R) and the yoke portion (44); and
the rotor (4U) is essentially made of laminated soft steel sheets.
A transverse flux machine apparatus comprising a stator (1U) and a rotor (4U), the stator (1U) having a stator core (2U) and a stator winding (3U) wound on the stator core (2U), wherein:
the stator core (2U) has left stator teeth (21L), right stator teeth (21R) and a yoke portion (24) connecting the left stator teeth (21L) and the right stator teeth (21R);
the winding (3U) is accommodated between the left stator teeth (21L) and the right stator teeth (21R);
the rotor (4U) has left rotor teeth (41L), right rotor teeth (41R) and a yoke portion (44) connecting the left rotor teeth (41L) and the right rotor teeth (41R);
the stator (1U) has a pair of a left stator (11U) and a right stator (12U) being adjacent to each other;
each of the right stator teeth (21R) of the left stator (11U) is disposed between adjacent each two of the left stator teeth (21L) of the right stator (12U);
the rotor (4U) has a pair of a left rotor (41U) and a right rotor (42U) being adjacent to each other; and
each of the right rotor teeth (41R) of the left rotor (41U) is disposed between adjacent each two of the left rotor teeth (41L) of the right rotor (42U).
The transverse flux machine apparatus according to claim 10, wherein:
the stator (2U) has left stator teeth (21L), right stator teeth (21R), left diagonal portions (25L), right diagonal portions (25R) and a yoke portion (24);
the left diagonal portions (25L) extending diagonally join the left stator teeth (21L) and the yoke portion (24);
the right diagonal portions (25R) extending diagonally join the right stator teeth (21R) and the yoke portion (24); and
the stator (2U) is essentially made of laminated soft steel sheets.
The transverse flux machine apparatus according to claim 10, wherein:
the rotor (4U) has left rotor teeth (41L), right rotor teeth (41R), left diagonal portions (45L), right diagonal portions (45R) and a ring-shaped yoke portion (44);
the left diagonal portions (45L) extending diagonally join the left rotor teeth (41L) and the yoke portion (44);
the right diagonal portions (45R) extending diagonally join the right rotor teeth (41R) and the yoke portion (44); and
the rotor (4U) is essentially made of laminated soft steel sheets.