JP2021016300A - Rotary electric machine - Google Patents

Abstract

To provide a rotary electric machine excellent in heat characteristics to increase efficiency in a low torque range.SOLUTION: A stator winding of a rotary electric machine comprises: a plurality of delta-connected first windings for high-speed output; and a plurality of second windings for low-speed output arranged to be connected between each connection point and each phase terminal for connecting the first windings. The rotary electric machine comprises a switching part which switches connection between each connection point and each phase terminal to a direct connection state and a connection state via the second windings. The first windings are installed on a rotor facing surface side in a shot, and the second windings are installed opposite to the rotor facing surface side in the slot. To the first windings, a current waveform flows, which is formed by superposing a harmonic waveform in which one or more of tertiary and 3+6n-th of current to be generated in the first windings are synthesized with a primary waveform which is a fundamental control waveform of the current generated by the drive circuit. The harmonic waveform is a specific harmonic waveform of which the total sum of the current while the primary waveform takes a positive value is positive, and the total sum of the current while the primary waveform takes a negative value is negative.SELECTED DRAWING: Figure 5

Description

The present invention relates to a rotary electric machine mounted on a vehicle such as a hybrid vehicle or an electric vehicle and used as an electric motor or a generator.

Conventionally, electric motors for electric vehicles are desired to exhibit high torque and high efficiency characteristics in a wide range from low speed to high speed. For such applications, Patent Documents 1 to 3 describe the low-speed region and the high-speed region, respectively, by switching the connection of the stator winding of the motor between a star connection (Y connection) and a delta connection (Δ connection). Discloses a technique for exerting optimum characteristics in the above.

Japanese Unexamined Patent Publication No. 64-34198 Japanese Unexamined Patent Publication No. 2014-54094 Japanese Patent No. 3948009

By the way, in the electric motor adopting the Y-Δ connection switching method as described above, in the low speed region, a large torque can be obtained for the same current by selecting the Y connection and applying a sufficiently high voltage. .. Further, since the impedance of the electric motor increases in proportion to the frequency, it is difficult for the current to flow in the high-speed region where the frequency is high. Therefore, by selecting the Δ connection having a low impedance, the current can easily flow. Therefore, in the Δ connection, high characteristics in the high speed and low torque region are important, and in the Y connection, an increase in the maximum output is desired.

It is also desired to improve the problem of heat that is inevitably generated when the stator winding is energized. Since the heat generated during this energization is copper loss, the Y connection in which the two phases are connected in series is larger than the Δ connection in which the U, V, and W phase windings are connected in parallel. It tends to be a problem on the connection side.

The present invention has been made in view of the above circumstances, and it is an object to be solved to provide a rotary electric machine having excellent thermal characteristics and capable of improving efficiency in a low torque range.

The present invention made to solve the above problems
A rotor (20) having a rotor core (21) provided with a plurality of magnet accommodating holes (22) arranged in the circumferential direction, and a permanent magnet (23) embedded in the magnet accommodating holes.
A stator core (31) provided with a plurality of slots (34) arranged radially opposite to the rotor core, and a plurality of phases housed in the slots and wound around the stator core. A stator (30) having a stator winding (40) of (U-phase, V-phase, W-phase) and
In the rotary electric machine (1) equipped with
The stator windings include a plurality of delta-connected high-speed output first windings (41), connection points (43U, 43V, 43W) connecting the first windings, and phase terminals (44U). , 44V, 44W), and a plurality of second windings (42) for low speed output arranged so as to be connectable.
The rotary electric machine includes a switching unit (45U, 45V, 45W) that switches between a state in which the connection between each connection point and each of the phase terminals is directly connected and a state in which the connection is connected via the second winding. ,
The first winding is installed on the rotor facing surface side in the slot.
The second winding is installed on the anti-rotor facing surface side in the slot.
In the first winding, the first-order waveform which is the basic control waveform of the current generated by the drive circuit is added to the third-order and 3 + 6n-th order of the current generated in the first winding (n is a natural number of 1 or more). The current of the waveform in which one or two or more of them are combined and the harmonic waveform is superimposed flows,
The harmonic waveform is a specific harmonic waveform in which the sum of the currents while the primary waveform takes a positive value is positive and the sum of the currents while the primary waveform takes a negative value is negative. is there.

According to this configuration, when the connection between each connection point connecting the delta-connected first windings and each phase terminal is switched to the state of being directly connected by the switching portion, the stator winding is used for high-speed output. It becomes a delta connection state. Further, when the connection between each connection point connecting the delta-connected first windings and each phase terminal is switched to the state of being connected via the second winding by the switching portion, the stator winding outputs at low speed. It will be in a star-delta connection state for use.

Then, when the stator winding switched to the star-delta connection is energized, the current flowing through the delta-connected first winding is smaller than the current flowing through the second winding, so that the first winding There is little heat generation due to copper loss. That is, since the copper loss is proportional to the square of the load current, the calorific value of the first winding is about 1/3 of the calorific value of the second winding. In the present invention, the first winding having a small calorific value is installed on the rotor facing surface side of the stator core, and the second winding having a large calorific value is installed on the anti-rotor facing surface side of the stator core. As a result, the stator winding has excellent thermal characteristics because the second winding, which generates a large amount of heat, is brought closer to the back core portion, which has a large heat capacity of the stator core, so that it can be easily heated and cooled. It becomes.

In addition, when a magnet-embedded rotor is used, the first winding, which generates less heat, is installed on the rotor facing surface side of the stator core, so the effect of heat on the magnet is reduced. , Magnet demagnetization can be suppressed. The torque of the magnet-embedded motor is the magnet torque obtained by multiplying the d-axis magnetic flux Ψ by the q-axis current, and the relaxation obtained by multiplying the difference between the q-axis inductance and the d-axis inductance by the d and q-axis currents. Although it is a difference in torque, in the low torque range, the weakening field current and the weakening field magnetic flux are not used because of the low current, so the magnet that uses the q-axis current rather than the reluctance torque that uses the d and q-axis currents. The ratio to the total torque tends to be biased toward the torque. Here, by concentrating the delta-connected first winding for high-speed output on the rotor facing surface side of the stator core, which is close to the magnet in the rotor and has a small magnetoresistance, a large amount of magnet magnetic flux Ψ can be output. Therefore, high efficiency can be achieved in a low torque region. Further, by concentrating the second winding for low-speed output on the anti-rotor facing surface side of the stator core, an inductance that becomes an effective reluctance torque especially at low-speed large torque output in which a strong current flows on the d and q axes is maintained. It is possible to suppress an unnecessarily increase in the magnetic flux Ψ, which can be an excessive voltage source when a large current is applied.

The reference numerals in parentheses after each member or part described in this column and the claims indicate the correspondence with the specific member or part described in the embodiment described later, and the patent. It does not affect the composition of each claim described in the claims.

FIG. 5 is a schematic cross-sectional view taken along the axial direction of the rotary electric machine according to the first embodiment. It is a perspective view of the stator which concerns on Embodiment 1. FIG. It is explanatory drawing which shows the state which inserts the conductor segment into the slot of the stator core in Embodiment 1. FIG. It is sectional drawing of the conductor segment used in Embodiment 1. FIG. FIG. 5 is a partial plan view of one magnetic pole of the rotor and the stator according to the first embodiment. It is a wiring diagram of the stator winding which concerns on Embodiment 1. FIG. It is explanatory drawing which shows the waveform of the electric current which flows through the stator winding in the rotary electric machine of Embodiment 1. It is explanatory drawing which shows the flow of the magnetic flux of the d-axis magnetic path and the q-axis magnetic path in the rotary electric machine of Embodiment 1. FIG. It is explanatory drawing which shows the stator magnetic flux when the specific harmonic waveform current is passed through the stator winding in the rotary electric machine of Embodiment 1. It is a graph which shows the relationship between the rotation speed and torque at the time of operating in the state where the stator winding is Δ-connected and the case where it is operated in the state of star-delta connection in the rotary electric machine of Embodiment 1. It is a partial plan view of one magnetic pole of the stator which concerns on Embodiment 2. FIG. FIG. 5 is a partial plan view of one magnetic pole of the stator according to the third embodiment. FIG. 5 is a cross-sectional view of a laminated conductor wire constituting the first winding of the stator winding according to the third embodiment. It is a wiring diagram of the stator winding which concerns on modification 1. FIG.

Hereinafter, embodiments of the rotary electric machine according to the present invention will be specifically described with reference to the drawings.

[Embodiment 1]
The rotary electric machine 1 according to the present embodiment is used as a vehicle electric motor (motor). As shown in FIG. 1, the rotary electric machine 1 has magnetic poles having different polarities in the circumferential direction due to a housing 10, a rotating shaft 13 rotatably supported by the housing 10, and a plurality of permanent magnets 23 embedded therein. It includes a rotor 20 that is formed and acts as a field magnet, and a stator 30 that has a stator core 31 and a stator winding 40 and acts as an armature.

The housing 10 is formed into a substantially cylindrical shape with both ends closed by a pair of bottomed tubular housing semi-members 10a and 10b. The pair of housing semi-members 10a and 10b are integrated by being fastened by bolts 11 with the openings facing each other. The rotating shaft 13 is rotatably supported on the wall portions on both sides of the housing 10 in the axial direction via a pair of bearings 12, 12.

The rotor 20 is rotatably fitted and fixed to the outer periphery of the central portion of the rotating shaft 13 rotatably supported by the housing 10 in the axial direction. As shown in FIG. 5 (partial plan view showing a part), the rotor 20 has a rotor core 21 having a plurality of magnet accommodating holes 22, a first flux barrier 25, a second flux barrier 26, and the like arranged in the circumferential direction. And a plurality of permanent magnets 23 embedded in each magnet accommodating hole 22.

The rotor core 21 is formed in a thick cylindrical shape by laminating a plurality of annular steel plates having a through hole 21a in the center in the axial direction, and the through hole 21a is fitted and fixed to the outer periphery of the rotating shaft 13. A plurality of pairs (8 pairs in the first embodiment) of magnet accommodating holes 22 penetrating in the axial direction are provided on the outer peripheral portion of the rotor core 21 at a predetermined distance in the circumferential direction. The magnet accommodating holes 22 are composed of two pairs and a plurality of pairs arranged in a V shape so as to be separated from each other toward the outer peripheral side. A central bridge 24 extending in the radial direction is provided between the pair of magnet accommodating holes 22, 22.

Each magnet accommodating hole 22 accommodates one permanent magnet 23 having a rectangular cross-sectional shape in the direction perpendicular to the rotation axis O of the rotor 20. In the case of the first embodiment, one magnetic pole is formed by a pair of permanent magnets 23, 23 housed in a pair of magnet housing holes 22, 22 arranged in a V shape. In this case, the eight pairs of permanent magnets 23, 23 form a plurality of magnetic poles (8 poles (N pole: 4, S pole: 4) in the first embodiment) having alternately different polarities in the circumferential direction. In one magnetic pole of the rotor 20, the pair of magnet accommodating holes 22, 22 and the pair of permanent magnets 23, 23 are line-symmetric with respect to the magnetic pole center line C1 passing through the rotation axis O of the rotor 20 and the magnetic pole center. (V-shaped state in which the outer peripheral side opens).

A q-axis core portion 27, which is a portion where a magnetic flux flows from one magnetic pole to another, is formed between two magnetic poles adjacent to each other in the circumferential direction of the rotor core 21 and having different polarities. A first flux barrier 25 as a magnetic gap is continuously connected to the magnet accommodation holes 22 between the permanent magnets 23 accommodated in the magnet accommodation holes 22 and the q-axis core portion 27 facing in the circumferential direction. And are provided integrally.

Further, on the magnetic pole center side of each of the paired magnet accommodating holes 22 and 22, paired second flux barriers 26 and 26 extending from the magnetic pole center side end of each magnet accommodating hole 22 toward the rotation axis O side are provided. It is provided. Between the paired second flux barriers 26, 26, a central bridge 24 formed between the paired magnet accommodating holes 22, 22 is formed so as to extend toward the rotation axis O.

As shown in FIG. 2, the stator 30 includes an annular stator core 31 arranged so as to face each other in the radial direction on the outer peripheral side of the rotor 20, and a plurality of phases (U phase, V phase, W) wound around the stator core 31. The stator winding 40 of the phase) is provided. The stator 30 is fixed to the inner circumference of the housing 10 so that the inner peripheral surface of the stator core 31 faces the outer peripheral surface of the rotor 20 in the radial direction via a predetermined air gap. In this case, the stator core 31 is axially sandwiched and fixed by a pair of housing half members 10a and 10b (see FIG. 1).

The stator core 31 is formed in an annular shape by laminating a plurality of electromagnetic steel plates in the axial direction. The stator core 31 has an annular back core portion 32 located on the outer peripheral side, and a plurality of teeth 33 protruding inward in the radial direction from the back core portion 32 and arranged at a predetermined distance in the circumferential direction. A slot 34 that opens in the inner peripheral surface of the stator core 31 and extends in the radial direction is formed between the side surfaces of the adjacent teeth 33 that face each other in the circumferential direction.

The slots 34 are formed at a ratio of two per phase of the stator winding 40 to the number of magnetic poles (8 magnetic poles) of the rotor 20, and the slot multiple is 2. In the case of the present embodiment, the number of slots 34 (number of slots Sn) is such that the slot multiple S (S is a positive integer) is 2, the number of magnetic poles Mn of the rotor 20 (Mn is a positive integer) is 8 poles, and the phase is Assuming that the number p (p is a positive integer) has three phases, Sn = S × Mn × p = 2 × 8 × 3 = 48.

The stator winding 40 wound in the slot 34 of the stator core 31 is composed of a plurality of U-shaped conductor segments 50 (see FIG. 3) in which the joint ends are joined to each other. As shown in FIG. 4, the conductor segment 50 is a two-layer insulating film composed of a conductor 56 having a rectangular cross section made of a conductive material such as copper or aluminum, and an inner layer 57a and an outer layer 57b, which covers the outer peripheral surface of the conductor 56. It is formed by bending a square wire consisting of 57 into a U shape.

As shown in FIG. 3, the conductor segment 50 formed in a U shape includes a pair of straight lines 51 and 51 parallel to each other and a turn portion 52 connecting one ends of the pair of straight lines 51 and 51 to each other. .. A crown portion 53 extending in parallel with the end surface 31a along the axial end surface 31a of the stator core 31 is provided in the central portion of the turn portion 52, and both sides of the crown portion 53 are provided with respect to the end surface 31a of the stator core 31. An inclined portion 54 inclined at a predetermined angle is provided. Reference numeral 39 is an insulator that electrically insulates between the stator core 31 and the stator winding 40.

FIG. 3 shows a set of two conductor segments 50A and 50B inserted and arranged in two adjacent slots 34A and 34B in the same phase. In this case, in the two conductor segments 50A and 50B, the pair of straight lines 51 and 51 are inserted separately from one end side in the axial direction into two adjacent slots 34A and 34B instead of the same slot 34. To. That is, in the two conductor segments 50A and 50B on the right side of FIG. 3, in one conductor segment 50A, one straight line portion 51 is inserted into the outermost layer (sixth layer) of one slot 34A, and the other straight line portion 51 is inserted. The portion 51 is inserted into the fifth layer of another slot (not shown) separated by one magnetic pole pitch (NS magnetic pole pitch) in the counterclockwise direction of the stator core 31.

Then, in the other conductor segment 50B, one straight portion 51 is inserted into the outermost layer (sixth layer) of the slot 34B adjacent to the slot 34A, and the other straight portion 51 is directed in the counterclockwise direction of the stator core 31. It is inserted into the fifth layer of another slot (not shown) separated by one magnetic pole pitch (NS magnetic pole pitch). That is, the two conductor segments 50A and 50B are arranged so as to be offset by one slot pitch in the circumferential direction. In this way, two conductor segments 50A and 50B are inserted and arranged in order in two layers with respect to all the slots 34, so that the straight portion 51 of four or more even-numbered conductor segments 50 is formed. Inserted and placed. In the case of the present embodiment, six straight portions 51 (first winding 41, second winding 42) are housed in each slot 34 in one radial row (see FIG. 5).

The open ends of the pair of straight portions 51, 51 extending from the slot 34 to the other end side in the axial direction are oblique to the end surface 31a of the stator core 31 at a predetermined angle so as to be oblique to the opposite sides in the circumferential direction. By being twisted, an oblique portion 55 (see FIG. 2) having a length approximately equal to the half-pole pitch is formed. Then, on the other end side of the stator core 31 in the axial direction, the terminal portions of the predetermined diagonal portions 55 of the conductor segment 50 are joined to each other by welding or the like, so that they are electrically connected in a predetermined pattern. That is, by connecting the predetermined conductor segments 50 to each other, the three-phase (U phase, V phase, W phase) are spirally wound in the circumferential direction along the slot 34 of the stator core 31. A stator winding 40 having windings is formed.

For each phase of the stator winding 40, a winding (coil) that makes six turns around the stator core 31 is formed by the basic U-shaped conductor segment 50. However, for each phase of the stator winding 40, the segment having the output lead wire and the neutral point lead wire integrally, and the first and second laps, ..., the fifth and sixth laps, respectively. The segment having the turn portion to be connected is composed of a deformed segment different from the basic conductor segment 50. Each phase winding of the stator winding 40 is connected in a predetermined state by using these deformed segments.

As shown in FIG. 6, the stator winding 40 of the first embodiment has a plurality of (three) first windings 41 for high-speed output delta-connected and each connection point for connecting the first windings 41 to each other. Multiple (three) second windings 42 for low speed output arranged so as to be connectable between 43U, 43V, 43W and each phase terminal 44U, 44V, 44W, and each connection point 43U, 43V, 43W. It has switching units 45U, 45V, 45W that switch between a state in which the connection with each phase terminal 44U, 44V, 44W is directly connected and a state in which the connection is made via the second winding 42.

The switching units 45U, 45V, and 45W are each composed of two switches controlled on and off by a controller (not shown), and the two switches are set so as to reverse each other and not be turned on at the same time. Has been done. When the switching portions 45U, 45V, 45W switch to a state in which the connection points 43U, 43V, 43W and the phase terminals 44U, 44V, 44W are directly connected, the stator winding 40 is delta-connected for high-speed output. (Δ connection). Further, when the switching unit 45U, 45V, 45W switches the connection between each connection point 43U, 43V, 43W and each phase terminal 44U, 44V, 44W via the second winding 42, the stator The winding 40 is a star-delta connection (Y-Δ connection) for low-speed output.

When the stator winding 40 is energized while being switched to the Y-Δ connection for low-speed output by the switching portions 45U, 45V, 45W, the current flowing through the Δ-connected first winding 41 is the second winding. Since it is less than the current flowing through the 42, the heat generated by the copper loss of the first winding 41 is also small. That is, since the copper loss is proportional to the square of the load current, the calorific value of the first winding 41 is about 1/3 of the calorific value of the second winding 42.

In this case, the first winding 41, which generates less heat, is installed on the rotor facing surface side (inner peripheral surface side) of the stator core 31, and the second winding 42 generates about three times as much heat as the first winding 41. Is installed on the anti-rotor facing surface side (outer peripheral surface side) of the stator core 31. Specifically, as shown in FIG. 5, among the conductor wires constituting the stator windings 40, which are accommodated in each slot 34 in one row in the radial direction, the first winding 41 is on the rotor facing surface side. There are two conductor wires (on the inner peripheral surface side), and the second winding 42 is four conductor wires on the anti-rotor facing surface side (outer peripheral surface side). That is, 2 m of conductor wires constituting the first winding 41 (two at m = 1 in the first embodiment) are accommodated in each slot 34. As a result, the second winding 42, which generates a large amount of heat, is brought closer to the back core portion 32, which has a large heat capacity of the stator core 31, so that the stator winding 40 is easily heated and cooled. Improvements are being made.

A three-phase AC voltage is applied to the stator winding 40 from the drive circuit 60. The drive circuit 60 has three phases so that a desired rotating magnetic field is generated from the stator winding 40 based on a signal output from a position sensor (not shown) or a controller (not shown) that detects the rotational position of the rotor 20. Apply voltage to the windings. In the first embodiment, a well-known inverter that generates a three-phase AC voltage is adopted as the drive circuit 60.

In the case of the first embodiment, as shown in FIG. 7, the first winding 41 connected by Δ has a first-order waveform (broken line) which is a basic control waveform, a third-order waveform, and a 3 + 6n-order waveform (n is 1 or more). Is a harmonic waveform (solid line) in which one or more of (natural numbers) are combined, and the total current when the primary waveform takes a positive value is positive and the primary waveform is negative. A current of a waveform (single-point chain line) in which a harmonic waveform (hereinafter, simply referred to as a “specific harmonic waveform”) in which the sum of the currents when taking a value is negative flows. In the first embodiment, as the specific harmonic waveform, a harmonic waveform in which the third order and the ninth order (n = 1) are combined is adopted. By concentrating the Δ-connected high-speed output first winding 41 on the rotor facing surface side of the stator core 31 where the originally high magnet magnetic flux Ψ exists, a large amount of magnet magnetic flux Ψ can be output, so that the torque is low. It is possible to improve efficiency in the area.

Hereinafter, the increase of the magnet magnetic flux Ψ using the third-order and 3 + 6n-th order harmonics will be described. In FIG. 8, between the rotor 20 and the stator 30, the d-axis magnetic path of the magnetic flux flowing on the d-axis is shown by a solid line, and the q-axis magnetic path of the magnetic flux flowing on the q-axis is shown by a broken line. Further, the solid line arrow described on the stator 30 indicates the stator magnetic flux generated in the stator 30 when the primary waveform current flows through the stator winding 40, and the longer the solid line arrow is, the stronger the magnetic flux is. Represents being strong.

In FIG. 9, the stator magnetic flux generated in the stator 30 when the above-mentioned specific harmonic waveform current is passed through the stator winding 40 is indicated by a solid arrow. In this case, stator magnetic fluxes that flow in opposite directions in the radial direction are generated on both sides of each phase winding arranged in two slots in the circumferential direction.

Further, the stator magnetic flux generated on the q-axis due to the primary waveform current and the stator magnetic flux generated on the q-axis due to the specific harmonic waveform current face each other in the opposite radial directions and cancel each other out on the q-axis. , The magnetic resistance on the d-axis magnetic path is reduced, and the magnetic flux on the d-axis magnetic path is easily passed. Therefore, the magnet magnetic flux Ψ can be output in a larger amount by passing the current of the waveform obtained by superimposing the specific harmonic waveform on the primary waveform through the stator winding 40.

According to the rotary electric machine 1 of the first embodiment configured as described above, among the stator windings 40, the first winding 41, which is Δ-connected and has a small heat generation amount, is on the rotor facing surface side (inner circumference) of the stator core 31. The second winding 42, which is installed on the side) and has a large heat generation amount, is installed on the anti-rotor facing surface side (outer peripheral side) of the stator core. Therefore, the stator winding 40 has excellent thermal characteristics because the second winding 42, which generates a large amount of heat, is brought closer to the back core portion 32, which has a large heat capacity of the stator core 31, and is easily heated and cooled. It becomes a thing. Further, since the first winding 41 having a small heat generation amount is installed on the rotor facing surface side of the stator core 31, the influence of heat on the permanent magnet 23 is reduced, so that demagnetization of the permanent magnet 23 is suppressed. be able to.

Further, a current having a waveform in which the above-mentioned specific harmonic waveform is superimposed on the primary waveform which is the basic control waveform flows through the Δ-connected first winding 41 of the stator winding 40. The magnet magnetic flux Ψ rises due to the action of the current of this specific harmonic. Further, by concentrating the Δ-connected high-speed output first winding 41 on the rotor facing surface side of the stator core 31 where the originally high magnet magnetic flux Ψ exists, a large amount of magnet magnetic flux Ψ can be output. As shown in FIG. 10, high efficiency can be achieved in a low torque region. Further, by concentrating the second winding 42 for low-speed output on the anti-rotor facing surface side of the stator core 31, it is possible to suppress an increase in the magnet magnetic flux Ψ and increase the inductance. Therefore, when the stator winding 40 is operated in a star-delta connection state, an increase in the maximum output in the low speed region can be realized as shown in FIG.

Further, in the first embodiment, the stator winding 40 has a plurality of terminals that are axially inserted into the slot 34 and have predetermined terminals at open ends extending outward from the axial end surface of the stator core 31 to be joined to each other. It is composed of conductor segments 50. Therefore, when the stator winding 40 is wound around the stator core 31, the first winding 41 installed on the rotor facing surface side of the stator core 31 and the second winding installed on the anti-rotor facing surface side of the stator core 31 The 42 can be clearly separated and wound. As a result, the work of joining the terminals of the conductor segments 50 can be easily performed. Further, since it is easy to change the type and thickness of the conductor wire forming the first winding 41 and the conductor wire forming the second winding 42, it is possible to select the conductor wire according to the characteristics required for each.

Further, in the first embodiment, the slot 34 accommodates an even number of conductor wires having a rectangular cross section constituting the stator winding 40 in one row in the radial direction, and the conductor wires forming the first winding 41 are accommodated. The slot 34 accommodates 2 m (2 in m = 1 in the first embodiment). Thereby, it is possible to clarify the distinction between the first winding 41 installed on the rotor facing surface side of the stator core 31 and the second winding 42 installed on the anti-rotor facing surface side of the stator core 31.

[Embodiment 2]
In the rotary electric machine of the second embodiment, the conductor wire forming the first winding 41 of the stator winding 40 has a smaller cross-sectional area than the conductor wire forming the second winding 42. Unlike the one, the other configurations are the same. Therefore, the elements common to the first embodiment are designated by the same reference numerals, detailed description thereof will be omitted, and different points and important points will be described below with reference to FIG.

In the second embodiment, similarly to the first embodiment, the conductor wires (first winding 41, second winding 42) having a rectangular cross section constituting the stator winding 40 are radially 1 in each slot 34 of the stator core 31. Six (even) are accommodated in each row. Then, in each slot 34, two first windings 41, which are Δ-connected and have a small amount of heat generation, are housed on the rotor facing surface side (inner peripheral surface side) of the stator core 31, and are approximately about the first winding 41. Four second windings 42, which generate three times as much heat, are housed on the anti-rotor facing surface side (outer peripheral surface side) of the stator core 31.

However, in the case of the second embodiment, the conductor wire of the first winding 41 has a cross-sectional area about 1/2 smaller than that of the conductor wire of the second winding 42. That is, the circumferential width of the conductor wire of the first winding 41 is the same as the circumferential width of the conductor wire of the second winding 42, but the radial width is the radial width of the conductor wire of the second winding 42. It is reduced to about 1/2 of the size and formed flat.

According to the rotary electric machine of the second embodiment configured as described above, among the stator windings 40, the first winding 41 which is Δ-connected and has a small heat generation amount is on the rotor facing surface side (inner circumference side) of the stator core 31. ), And the second winding 42, which generates a large amount of heat, is installed on the anti-rotor facing surface side (outer peripheral side) of the stator core. Therefore, the same operations and effects as those in the first embodiment can be obtained, such as excellent thermal characteristics of the stator winding 40 and high efficiency in a low torque range.

Further, in the second embodiment, the conductor wire forming the first winding 41 of the stator winding 40 has a smaller cross-sectional area than the conductor wire forming the second winding 42, so that the first winding 41 It is possible to reduce the eddy current loss generated in the conductor wire of. Since the rotor facing surface side (inner peripheral surface side) of the stator core 31 in which the first winding 41 is installed is close to the permanent magnet 23 of the rotor 20, the magnet magnetic flux Ψ increases and the leakage flux also increases. Therefore, as in the second embodiment, the eddy current loss can be reduced by reducing the cross-sectional area of the conductor wire of the first winding 41, so that the efficiency can be further improved in the low torque range. ..

In the second embodiment, the conductor wire of the first winding 41 is formed in a flat shape and has a smaller cross-sectional area than the conductor wire of the second winding 42. Instead of this, the first winding The wire 41 may be composed of a plurality of parallel windings connected in parallel, and the cross-sectional area of each parallel winding may be smaller than the cross-sectional area of the conductor wire of the second winding 42.

[Embodiment 3]
The rotary electric machine of the third embodiment is different from that of the second embodiment in that the laminated conductor wire 58 is adopted as the conductor wire constituting the first winding 41 of the stator winding 40, and the other configurations are the same. is there. Therefore, the elements common to the second embodiment are designated by the same reference numerals and detailed description thereof will be omitted, and different points and important points will be described below with reference to FIGS. 12 and 13.

The laminated conductor wire 58 constituting the first winding 41 of the third embodiment is two flat wires composed of a flat conductor 58a made of a conductive material and a first insulating film 58b covering the outer peripheral surface of the conductor 58a. Is laminated in an insulated state, and further has a second insulating film 58c that covers the outer peripheral surfaces of the two flat wires. In the laminated conductor wire 58, the conductors 58a and 58a laminated at both ends in the stretching direction are joined to each other. In this case, the cross-sectional area of the conductor 58a is reduced to about 1/2 of the cross-sectional area of the conductor 56 of the conductor wire constituting the second winding 42. Therefore, the total cross-sectional area of the two conductors 58a constituting one laminated conductor wire 58 is substantially the same as the cross-sectional area of the conductors 56 constituting one conductor wire of the second winding 42.

According to the rotary electric machine of the third embodiment configured as described above, in addition to being able to obtain the same operations and effects as those of the first embodiment, as in the second embodiment, the laminated conductor of the first winding 41 Since the eddy current loss generated in the wire 58 can be reduced, it is possible to further improve the efficiency in the low torque range. In the case of the third embodiment, the total cross-sectional area of the conductor 58a of one laminated conductor wire 58 is maintained substantially the same as the cross-sectional area of the conductor 56 of the second winding 42.

[Other Embodiments]
The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

For example, in the above embodiment, the switching portions 45U, 45V, 45W of the stator winding 40 are each composed of two switches controlled on and off by a controller (not shown), but the modification 1 shown in FIG. 14 As described above, a relay that is cheaper than the above switch may be adopted. In this case, each relay is controlled by a controller (not shown), and the connection between each connection point 43U, 43V, 43W and each phase terminal 44U, 44V, 44W is directly connected and via the second winding 42. Switch to either of the connected states.
Further, in the third embodiment, the laminated conductor wire 58 is adopted only for the first winding 41, but the laminated conductor wire 58 may be adopted for the second winding 42 as well.

Further, in the above embodiment, an example in which the present invention is applied to a vehicle generator (motor) as a rotary electric machine has been described, but a rotary electric machine used as a single function as an electric machine or a generator in a vehicle or the like, or The present invention can be applied to a rotary electric machine that can selectively use both functions.

1 ... Vehicle electric motor (rotary electric machine), 20 ... Rotor, 31 ... Stator core, 34 ... Slot, 40 ... Stator winding, 41 ... First winding, 42 ... Second winding, 43U, 43V, 43W ... Connection point , 44U, 44V, 44W ... phase terminal, 45U, 45V, 45W ... switching part, 50 ... conductor segment, 58 ... laminated conductor wire, 58a ... conductor.

Claims (5)

A rotor (20) having a rotor core (21) provided with a plurality of magnet accommodating holes (22) arranged in the circumferential direction, and a permanent magnet (23) embedded in the magnet accommodating holes.
A stator core (31) provided with a plurality of slots (34) arranged radially opposite to the rotor core, and a plurality of phases housed in the slots and wound around the stator core. A stator (30) having a stator winding (40) of (U-phase, V-phase, W-phase) and
In the rotary electric machine (1) equipped with
The stator windings include a plurality of delta-connected high-speed output first windings (41), connection points (43U, 43V, 43W) connecting the first windings, and phase terminals (44U). , 44V, 44W), and a plurality of second windings (42) for low speed output arranged so as to be connectable.
The rotary electric machine includes a switching unit (45U, 45V, 45W) that switches between a state in which the connection between each connection point and each of the phase terminals is directly connected and a state in which the connection is connected via the second winding. ,
The first winding is installed on the rotor facing surface side in the slot.
The second winding is installed on the anti-rotor facing surface side in the slot.
In the first winding, the first-order waveform which is the basic control waveform of the current generated by the drive circuit is added to the third-order and 3 + 6n-th order of the current generated in the first winding (n is a natural number of 1 or more). The current of the waveform in which one or two or more of them are combined and the harmonic waveform is superimposed flows,
The harmonic waveform is a specific harmonic waveform in which the sum of the currents while the primary waveform takes a positive value is positive and the sum of the currents while the primary waveform takes a negative value is negative. There is a rotary electric machine. The stator winding is composed of a plurality of conductor segments (50) that are axially inserted into the slot and have predetermined terminals at open ends extending outward from the axial end surface of the stator core to be joined to each other. The rotary electric machine according to claim 1. In the slot, an even number of conductor wires having a rectangular cross section constituting the stator winding are accommodated in one row in the radial direction, and 2 m (m) of conductor wires constituting the first winding are accommodated in the slot. The rotary electric machine according to claim 2, wherein is accommodated by 1 or more natural numbers. The rotary electric machine according to any one of claims 1 to 3, wherein the conductor wire forming the first winding has a cross-sectional area smaller than that of the conductor wire forming the second winding. At least one of claims 1 to 4, wherein the conductor wire constituting the first winding is a laminated conductor wire (58) in which a plurality of flat plate-shaped conductors (58a) are laminated in an insulated state. The rotary electric machine described in.

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