JP5885423B2 - Permanent magnet rotating electric machine - Google Patents

Description

  Embodiments described herein relate generally to a permanent magnet type rotating electrical machine.

  In general, in a permanent magnet type rotating electrical machine, the interlinkage magnetic flux of the permanent magnet is always generated with a constant strength, so that the counter electromotive voltage (also referred to as induced voltage) by the permanent magnet increases in proportion to the rotational speed. However, when a permanent magnet type rotating electrical machine is operated at a variable speed from a low speed to a high speed, the back electromotive force by the permanent magnet becomes extremely high in the high speed rotation range. Therefore, in the permanent magnet type rotating electrical machine, the counter electromotive voltage reaches the power supply voltage upper limit value, and it becomes impossible to apply the excitation voltage for flowing the current necessary for the output. As a result, the permanent magnet type rotating electrical machine not only greatly reduces the output in the high-speed rotation range, but also cannot be operated at a variable speed in a wide range up to the high-speed rotation range. In order to solve such problems, when the permanent magnet type rotating electrical machine is designed so that the amount of magnetic flux of the permanent magnet is equal to or lower than the withstand voltage, the permanent magnet type rotating electrical machine decreases the output and efficiency in the low speed rotation range. .

  As a method of expanding the range of the variable speed operation of the permanent magnet type rotating electrical machine, there is a method of applying a flux weakening control to the permanent magnet type rotating electrical machine. The total interlinkage magnetic flux amount of the armature winding is composed of a magnetic flux due to the d-axis current and a magnetic flux due to the permanent magnet, but decreases when a magnetic flux due to a negative d-axis current is generated by the weakening magnetic flux control. In a permanent magnet type rotating electrical machine to which such a weak flux control is applied, the linkage flux is reduced by the magnetic flux due to the negative d-axis current, so the decrease in linkage flux provides a voltage margin with respect to the upper limit of the power supply voltage. create. Therefore, the permanent magnet type rotating electrical machine to which such a flux-weakening control is applied can increase the current as a torque component, so that the output in the high-speed rotation region can be increased and the rotation speed is increased by a margin of voltage. Therefore, the range of variable speed operation can be expanded.

  However, since the permanent magnet type rotating electrical machine to which such a flux-weakening control is applied constantly flows a negative d-axis current that does not contribute to the output, the efficiency is deteriorated due to an increase in copper loss. Further, the demagnetizing field due to the negative d-axis current generates a harmonic magnetic flux, and an increase in voltage generated by the harmonic magnetic flux or the like creates a limit of voltage reduction by the flux weakening control. Therefore, it is difficult for the permanent magnet type rotating electrical machine to which the flux-weakening control is applied to operate at a variable speed that is three times or more the base speed. In addition, the permanent magnet type rotating electrical machine to which weak flux control is applied increases the iron loss due to the harmonic flux, so the efficiency is greatly reduced in the middle and high-speed rotation range, and vibration is generated by electromagnetic force due to the harmonic flux. Let

  In order to solve the above problems, a permanent magnet type rotation that reduces the iron loss in the high-speed range by changing the frequency of the rotating electrical machine by arranging a magnetic body movable in the radial direction and changing the number of poles of the rotor. There is an electric machine. However, the rotor is structurally complicated because it is necessary to provide a moving mechanism to move the magnetic body.

  Further, in order to solve the above problems, a low coercive force permanent magnet (hereinafter referred to as a variable magnetic force magnet) whose magnetic flux density is irreversibly changed by a magnetic field generated by an armature winding current, and a variable magnetic force magnet There is a permanent magnet type rotating electrical machine in which a high coercive force permanent magnet (hereinafter referred to as a fixed magnetic force magnet) such as NdFeB having a coercive force twice or more of the above is provided. In such a permanent magnet type rotating electrical machine, the total interlinkage magnetic flux between the variable magnetic magnet and the fixed magnetic magnet is adjusted by adjusting the amount and direction of the magnetic flux of the variable magnetic magnet in the high speed rotation range where the power supply voltage exceeds the maximum voltage. Adjust to reduce. A permanent magnet type rotating electrical machine in which such a fixed magnetic magnet and a variable magnetic magnet are arranged can change the number of poles of the rotor by reversing the magnetization direction of the variable magnetic magnet to facilitate wide variable speed operation. Can do.

JP 2006-280195 A JP 2008-48514 A JP-A-4-331447

Design and control of embedded magnet synchronous motor, Yoji Takeda et al., Ohm Basic research on pole number conversion memory motor, 2011 IEEJ National Conference 5-017

  However, a permanent magnet type rotating electrical machine in which a fixed magnetic magnet and a variable magnetic magnet are arranged has a case where the mounting space is limited, and there are cases where it is applied to an in-vehicle driving rotating electrical machine that requires high output density and high torque density. Therefore, the size (cross-sectional area) of the rotor is limited. Since the magnetic force of the variable magnetic magnet is smaller than that of the fixed magnetic magnet, the rotor cannot be equipped with a variable magnetic magnet that can sufficiently reduce the amount of interlinkage magnetic flux in the high-speed rotation range where the power supply voltage exceeds the maximum voltage. . Further, in the high-speed operation range, the iron loss increases in proportion to the square of the rotation speed (electric frequency), so the iron loss that can be suppressed by the variable magnetic force of the permanent magnet is limited.

  Further, the conventional configuration in which the number of poles of the rotor is changed by reversing the magnetization direction of the variable magnetic force magnet needs to change the connection of the armature winding. Therefore, it is necessary for the permanent magnet type rotating electrical machine to add additional devices such as a switching device and switching control means for changing the connection of the armature winding. The addition of such an accessory has problems such as an increase in the size of the permanent magnet type rotating electrical machine and an increase in cost due to the addition of the accessory.

  An object of the present invention is to provide a permanent magnet type rotating electrical machine that can improve the operation efficiency by changing the number of poles of a rotor without requiring a change in connection of armature windings.

  According to the embodiment, the permanent magnet type rotating electrical machine has a stator and a rotor. The stator has armature windings. The rotor includes a rotor iron core and a permanent magnet embedded in the rotor iron core. The permanent magnet type rotating electrical machine switches the phase sequence of the armature winding without changing the connection of the armature winding, and the polarity of the permanent magnet is changed by a magnetic field formed by energizing the armature winding. To change the number of poles of the rotor.

FIG. 2 is a radial cross-sectional view of the permanent magnet type rotating electric machine according to the first embodiment. 1 is a block diagram of a control system of a permanent magnet type rotating electrical machine according to a first embodiment. FIG. 3 is a three-phase current waveform diagram in the permanent magnet type rotating electric machine according to the first embodiment. FIG. 3 is an enlarged radial cross-sectional view of the permanent magnet type rotating electric machine according to the first embodiment. FIG. 3 is an enlarged radial cross-sectional view of the permanent magnet type rotating electric machine according to the first embodiment. FIG. 3 is a waveform diagram of a counter electromotive voltage in the permanent magnet type rotating electric machine according to the first embodiment. The radial cross-section enlarged view of the permanent-magnet-type rotary electric machine which concerns on 2nd Embodiment. The radial cross-section enlarged view of the permanent-magnet-type rotary electric machine which concerns on 2nd Embodiment. The radial cross-section enlarged view of the permanent-magnet-type rotary electric machine which concerns on 3rd Embodiment. The radial cross-section enlarged view of the permanent-magnet-type rotary electric machine which concerns on 3rd Embodiment. The wave form diagram of the counter electromotive voltage in the permanent magnet type rotary electric machine which concerns on 4th Embodiment.

Hereinafter, the present embodiment will be described with reference to the drawings.
(First embodiment)
First, the configuration of the permanent magnet type rotating electrical machine (permanent magnet type reluctance type rotating electrical machine) 1 according to the first embodiment will be described. FIG. 1 is a cross-sectional view in the radial direction of the permanent magnet type rotating electrical machine 1 according to the first embodiment. The permanent magnet type rotating electrical machine 1 includes a stator 10 and a rotor 20. The stator 10 is cylindrical. The rotor 20 has a cylindrical shape, and is disposed coaxially with the stator 10 inside the through hole of the stator 10. The rotor 20 has a radial size such that the outer peripheral surface thereof has a slight gap (air gap) with the inner peripheral surface of the stator 10.

  The stator 10 includes a stator core 101 and an armature winding 102. The stator core 101 is configured by laminating electromagnetic steel plates. The stator core 101 has a stator tooth 1011 and a stator slot 1012 on the inner peripheral side. The stator teeth 1011 face the rotor 10 and extend radially from the stator core 101 toward the rotor 10. A plurality of stator teeth 1011 are provided at equal intervals in the circumferential direction of the stator 10. In the first embodiment, the number of stator teeth 1011 is 36. Stator slot 1012 is a groove for accommodating armature winding 102 provided between adjacent stator teeth 1011. In the first embodiment, the number of stator slots 1012 is 36 slots equal to the number of stator teeth 1011. Note that the number of slots of the stator slot 1012 is determined based on the number of poles of the rotor 20 as described later. The armature winding 102 is concentratedly wound around each stator tooth 1011. Each armature winding 102 is applied with an AC current of any one of the U phase (U shown in FIG. 1), the V phase (V shown in FIG. 1), and the W phase (W shown in FIG. 1).

  The rotor 20 includes a rotor core 201 and a permanent magnet 202. The rotor core 201 is configured by laminating electromagnetic steel plates. In the rotor core 201, easy magnetization directions and difficult magnetization directions are alternately formed in the circumferential direction around the rotation shaft 203. The rotor core 201 has an insertion hole 2011 in the axial direction of the rotary shaft 203 along the easy magnetization direction in order to form magnetic irregularities on the outer peripheral surface. A plurality of insertion holes 2011 are provided at equal intervals in the circumferential direction of the rotor core 201. In the first embodiment, the number of insertion holes 2011 is 48. The permanent magnet 202 is embedded in the insertion hole 2011 and fixed with an adhesive or the like. A plurality of permanent magnets 202 are embedded at equal intervals in the circumferential direction of the rotor core 201. The magnetization direction of each permanent magnet 202 embedded in the rotor core 201 is either the direction from the rotor 20 toward the stator 10 or the opposite direction. In the first embodiment, the number of permanent magnets 202 is 48 equal to the number of insertion holes 2011. The permanent magnet 202 includes a fixed magnetic magnet 2021 and a variable magnetic magnet 2022. In the first embodiment, the term permanent magnet 202 is used as a general term including at least one of a fixed magnetic magnet 2021 and a variable magnetic magnet 2022.

  Next, the arrangement of the fixed magnetic magnet 2021 and the variable magnetic magnet 2022 will be described. In the first embodiment, the fixed magnetic magnet 2021 and the variable magnetic magnet 2022 are arranged in the rotor core 201 so that the number of poles of the rotor 20 is 48 poles or 24 poles equal to the number of permanent magnets 202. Will be described. The two fixed magnetic magnets 2021 and the two variable magnetic magnets 2022 are alternately arranged in the rotor core 201 in the circumferential direction. Further, each fixed magnetic magnet 2021 has a magnetization direction of a fixed magnetic magnet 2021 whose magnetization direction is adjacent in the circumferential direction (including the fixed magnetic magnet 2021 adjacent in the circumferential direction with two variable magnetic magnets 2022 interposed therebetween). The rotor core 201 is disposed in the opposite direction.

Next, application control of a three-phase alternating current to each armature winding 102 will be described. FIG. 2 is a block diagram showing a control system of the permanent magnet type rotating electrical machine 1 according to the first embodiment. The permanent magnet type rotating electrical machine 1 is controlled so as to output an inverter 30 for driving it, a DC voltage source 40 connected to the DC side thereof, and a torque that matches the required torque command Tm ^*. An inverter control unit 50 is provided.

The inverter control unit 50 controls the inverter 30 so that torque that matches the requested torque command is output. In response to the torque command Tm ^* , the DQ axis current command calculation unit 501 calculates a DQ axis current command. On the other hand, the rotor mechanical angle θm of the permanent magnet type rotating electrical machine 1 is detected by the position detector 60. The electrical angle calculation unit 502 multiplies the rotor mechanical angle θm by the number of poles, adds the offset phase angle θ that adjusts the reference phase angle, and calculates the electrical angle θdq. The electrical angle θdq corresponds to the phase angle of the D axis with respect to the U phase. What are the currents Iu and Iw of the permanent magnet type rotating electrical machine 1? The current is detected by the current detectors 70 and 80, and is converted into a current value on the DQ coordinate system by the coordinate converter 503 in accordance with the electrical angle θdq. The current control unit 504 controls the DQ axis output voltage commands Vd ^* and Vq ^* so that the DQ axis current matches each current command value. The coordinate converter 505 converts the DQ axis output voltage commands Vd ^* , Vq ^* into three-phase voltage commands Vu ^* , Vv ^* , Vw ^* , and the PWM controller 506 generates a gate signal to the switching element of the inverter 30. To do.

  Furthermore, the pole number switching setting unit 507 switches the number of poles of the rotor 20 between the A pole and the B pole with the rotation speed of the permanent magnet type rotating electrical machine 1 as an input. The change in the number of poles of the rotor 20 will be described later. The pole number switching setting unit 507 determines the low speed side as the A pole and the high speed side as the B pole according to a predetermined switching rotation speed. When the efficiency is more strictly maximized, the pole number switching setting unit 507 sets the switching frequency according to the inverter DC voltage and the torque command in addition to the rotation speed.

  When the pole number switching setting unit 507 selects the low speed rotation based on the rotation number calculated by the rotation number calculation unit 508 (inverter FLG = 0), the inverter control unit 50 performs control by regarding the motor as an A pole. The electrical angle calculator 502 multiplies the detected rotor mechanical angle θm by the number of pole pairs (N / 2), and adds the phase angle reference to the offset phase angle θα to obtain the electrical angle θdq. Further, when the DQ-axis current command calculation unit 501 is regarded as an A-pole motor, the N-pole DQ current command calculation unit 501a is used. On the other hand, when the pole number switching setting unit 507 selects high-speed rotation based on the rotation number calculated by the rotation number calculation unit 508, the inverter control unit 50 performs control by regarding it as a B-pole motor. Note that the electrical angle calculation unit 502 sets the apparent number of pole pairs to be multiplied here to be (−B / 2) in order to reverse the phase order in the part to be multiplied by the number of poles. Thereby, the inverter operation | movement of the permanent-magnet-type rotary electric machine 1 which made the phase order reverse by the time of A pole and the time of B pole is attained. The rotor 20 rotates around the rotor shaft 203 by a rotating magnetic field generated by a current flowing through each armature winding 102.

  Inverter control unit 50 detects that the number of poles setting has changed, and then flows the DQ axis current command set by pole number switching excitation current command calculation unit 510 for a predetermined time set by timer 509. Thus, the number of poles is changed by switching the magnetization direction (polarity) of the variable magnetic force magnet 2022. That is, the inverter 30 causes a magnetic field formed by a pulsed magnetizing current to be passed through the armature winding 102 for a very short time to act on the variable magnetic force magnet 2022, and irreversibly changes the magnetization direction of the variable magnetic force magnet 2022. By doing so, the number of poles of the rotor 20 can be switched to reduce from the A pole to the B pole.

  FIG. 3 is a graph showing a three-phase current waveform in the permanent magnet type rotating electrical machine 1 according to the first embodiment. FIG. 3 shows three-phase current waveforms before and after switching the inverter 30 to reduce the number of poles of the rotor 20 from the A pole to the B pole. As shown in FIG. 3, the three-phase alternating current has different frequencies, different phase sequences, different phases, and different current amplitudes before and after the inverter 30 switches the number of poles of the rotor 20 from the A pole to the B pole. . The reason why the inverter 30 switches from the phase order of the U phase, the V phase, and the W phase to the phase order of the U phase, the W phase, and the V phase is that the rotating direction of the rotating magnetic field is reversed as the number of poles is changed. This is because the phase order of the armature winding 102 must be changed in order to make the rotation direction of the same as before the change in the number of poles.

  Next, the operation of the permanent magnet type rotating electrical machine 1 according to the first embodiment will be described. 4 is an enlarged cross-sectional view of a broken line portion in FIG. FIG. 4 shows the magnetization state of each variable magnetic force magnet 2022 when the number of poles of the rotor 20 is 48. The arrows in FIG. 4 indicate the magnetization directions of the fixed magnetic magnets 2021 and the variable magnetic magnets 2022. Each variable magnetic force magnet 2022 is magnetized by the action of the armature winding 102 such that the respective magnetization direction is opposite to the magnetization direction of the adjacent permanent magnet 202. One pole of the rotor 20 is formed by one of a fixed magnetic magnet 2021 and a variable magnetic magnet 2022. Therefore, the number of poles of the rotor 20 is 48, which is equal to the number of permanent magnets 202 arranged on the rotor core 201. At this time, the inverter 30 applies an alternating current to each armature winding 102 in the phase order of the U phase, the V phase, and the W phase as in the case of the A pole in FIG. The alternating current applied to each armature winding 102 is indicated by U (corresponding to the U phase), V (corresponding to the V phase), and W (corresponding to the W phase) in FIG.

  FIG. 5 is an enlarged cross-sectional view taken along a broken line in FIG. FIG. 5 shows the magnetization state of each variable magnetic force magnet 2022 when the number of poles of the rotor 20 is changed from 48 poles to 24 poles. The arrows in FIG. 5 indicate the magnetization directions of the fixed magnetic magnets 2021 and the variable magnetic magnets 2022. Each variable magnetic force magnet 2022 is magnetized so that the direction of magnetization is reversed by the action of the armature winding 102 so as to be in the same direction as the magnetization direction of the adjacent fixed magnetic force magnet 2021. One pole of the rotor 20 is formed by an adjacent fixed magnetic magnet 2021 and variable magnetic magnet 2022. Therefore, the number of poles of the rotor 20 is 48, which is half of the number of permanent magnets 202 arranged in the rotor core 201. As the number of poles of the rotor 20 changes, the inverter 30 applies an alternating current to each armature winding 102 in the phase order of the U phase, the W phase, and the V phase as in the case of the B pole in FIG. Switch to apply. The alternating current applied to each armature winding 102 is indicated by U (corresponding to U phase), W (corresponding to W phase), and V (corresponding to V phase) in FIG.

  Next, the change in the back electromotive force by the permanent magnet 202 according to the difference in the number of poles of the rotor 20 will be described. FIG. 6 is a graph showing the relationship of the counter electromotive voltage with respect to the electrical angle in the permanent magnet type rotating electrical machine 1 according to the first embodiment. The A pole shown in FIG. 6 is a case where the number of poles of the rotor 20 is 48, and the B pole is a case where the number of poles of the rotor 20 is 24. Note that the position of the central axis of an arbitrary pole having a polarity in the direction from the rotor 20 toward the stator 10 is defined as an electrical angle of 0 °. According to the graph shown in FIG. 6, when the number of poles of the rotor 20 is 24 poles (B pole), the period is 1/0 compared to the case where the number of poles of the rotor 20 is 48 poles (A pole). 2 and the amplitude of the back electromotive force generated by the permanent magnet 202 is halved.

  In the first embodiment, the example in which the two fixed magnetic magnets 2021 and the two variable magnetic magnets 2022 and the rotor core 201 are alternately arranged in the circumferential direction has been described. The arrangement of the magnets 202 is not limited to this. The arrangement and the combination of the number of fixed magnetic magnets 2021 and variable magnetic magnets 2022 are not limited as long as the number of poles of the rotor 20 is 48 or 24.

  Further, the configuration of the permanent magnet type rotating electrical machine 1 in which the number of poles of the rotor 20 is 48 or 24 and the stator slot 1012 is 36 slots has been described as an example, but the first embodiment uses the permanent magnet 202. It can be applied regardless of the type, number of poles and number of slots of the rotating electrical machine. In the first embodiment, the number of slots of the stator slot 1012 is (24 poles + 48 poles) / 2 = 36 slots in the stator core 101 when the number of poles of the rotor 20 is variable between 24 poles and 48 poles. Although an example of formation has been described, this can be generalized as follows. That is, when the number of poles of the rotor 20 is variable between 2n poles and 4n poles, the number of slots of the stator slots 1012 may be formed in the stator core 101 with (2n poles + 4n poles) / 2 = 3n slots. . Note that n is an integer.

  According to the first embodiment, the following effects can be obtained. The permanent magnet type rotating electrical machine 1 changes the number of poles of the rotor 20 by changing the magnetization direction of the variable magnetic force magnet 2022, thereby changing the connection of each armature winding 102 from low speed to high speed. High efficiency and variable speed operation is possible in a wide range of operation. The permanent magnet type rotating electrical machine 1 operates at a high torque with the number of poles of the rotor 20 being 48 poles (4n poles) in the low speed operation area, and the number of poles of the rotor 20 is 48 poles (4n poles) in the middle and high speed operation areas. ) To be reduced to 24 poles (2n poles) and operated at a high output, the counter electromotive voltage caused by the permanent magnet 202 can be suppressed. Therefore, since the permanent magnet type rotating electrical machine 1 can significantly reduce the iron loss without operating by applying the flux-weakening control by reducing the electrical frequency by half, the efficiency and reliability are improved. Further, even when the permanent magnet type rotating electrical machine 1 is operated by changing the number of poles of the rotor 20, the arrangement itself of the armature windings 102 is the same. Therefore, the permanent magnet type rotating electrical machine 1 does not require an auxiliary device such as a switch for changing the connection of each armature winding 102 and a switching control means, and there is no increase in the size of the rotating electrical machine. Can be provided.

(Second Embodiment)
First, the configuration of the permanent magnet type rotating electrical machine 1 according to the second embodiment will be described. 7 and 8 are cross-sectional views in the radial direction of the permanent magnet type rotating electrical machine 1 according to the second embodiment. Note that the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. In the second embodiment, the number of stator teeth 1011 is 9 and the number of stator slots 1012 is 36 slots equal to the number of stator teeth 1011. Note that the number of slots of the stator slot 1012 is determined based on the number of poles of the rotor 20 as described later. The number of insertion holes 2011 provided in the rotor core 201 is 40, and the number of permanent magnets 202 is 40 equal to the number of insertion holes 2011.

  The fixed magnetic magnet 2021 and the variable magnetic magnet 2022 are arranged on the rotor core 201 so that the number of poles of the rotor 20 is 10 poles or 8 poles. Any combination of the arrangement and the number of the fixed magnetic magnets 2021 and the variable magnetic magnets 2022 may be used without any limitation.

  Next, the operation of the permanent magnet type rotating electrical machine 1 according to the second embodiment will be described. FIG. 7 shows a case where the number of poles of the rotor 20 is 10. The arrows in FIG. 7 indicate the polarities of the poles of the rotor 20. Each variable magnetic magnet 2022 is magnetized by the action of the armature winding 102. The number of poles of the rotor 20 is 10 poles due to the magnetization of each variable magnetic force magnet 2022. At this time, the inverter 30 applies an alternating current to each armature winding 102 in the phase order of the U phase, the V phase, and the W phase as in the case of the A pole in FIG. The AC current applied to each armature winding 102 is shown in FIG. 7 as U (corresponding to U phase), V (corresponding to V phase), -V (corresponding to -V phase), W (corresponding to W phase). , -W (corresponding to -W phase).

  FIG. 8 shows a case where the number of poles of the rotor 20 is eight. The arrows in FIG. 8 indicate the polarities of the poles of the rotor 20. Each variable magnetic magnet 2022 is magnetized by the action of the armature winding 102. The number of poles of the rotor 20 is reduced from 10 poles to 8 poles by reversing the magnetization direction of each variable magnetic force magnet 2022. Note that the inverter 30 applies an alternating current to each armature winding 102 in the order of the U phase, the W phase, and the V phase in accordance with the change in the number of poles of the rotor 20 as in the case of the B pole in FIG. Switch to apply. The AC current applied to each armature winding 102 is shown in FIG. 8 as U (corresponding to U phase), -U (corresponding to -U phase), W (corresponding to W phase), -W (corresponding to -W phase). Corresponding), V (corresponding to the V phase), and -V (corresponding to the -V phase).

  In the second embodiment, the number of slots of the stator slot 1012 is (8 poles + 10 poles) / 2 = 9 slots when the number of poles of the rotor 20 is variable between 8 poles and 10 poles. Although the example formed in 101 has been described, this can be generalized as follows. That is, the number of slots of the stator slot 1012 may be formed in the stator core 101 with (8n + 10n) = 9n slots when the number of poles of the rotor 20 is variable between 8n poles and 10n poles. Note that n is an integer.

  According to the second embodiment, as described in the first embodiment, when the number of poles of the rotor 20 is 8n poles, compared to the case where the number of poles of the rotor 20 is 10n poles, The period becomes ½, and the amplitude of the counter electromotive voltage generated by the permanent magnet 202 is halved. According to 2nd Embodiment, there exists an effect similar to the effect demonstrated in 1st Embodiment. Furthermore, according to the second embodiment, the combination of the 10n pole 9n slot and the 8n pole 9n slot has a higher winding coefficient than other combinations of the number of poles and the number of slots. High torque can be realized. Therefore, according to the second embodiment, it is possible to provide the permanent magnet type rotating electrical machine 1 having higher efficiency, higher output density, and higher torque density.

(Third embodiment)
First, the configuration of the permanent magnet type rotating electrical machine 1 according to the third embodiment will be described. 9 and 10 are sectional views in the radial direction of the permanent magnet type rotating electrical machine 1 according to the third embodiment. In addition, the same code | symbol is attached | subjected to the structure same as 1st Embodiment and 2nd Embodiment, and description is abbreviate | omitted. In the third embodiment, the number of stator teeth 1011 is 12, and the number of stator slots 1012 is 12 slots equal to the number of stator teeth 1011. Note that the number of slots of the stator slot 1012 is determined based on the number of poles of the rotor 20 as described later. The number of insertion holes 2011 provided in the rotor core 201 is 70, and the number of permanent magnets 202 is 70 equal to the number of insertion holes 2011.

  The fixed magnetic magnet 2021 and the variable magnetic magnet 2022 are arranged on the rotor core 201 so that the rotor 20 has 14 or 10 poles. Any combination of the arrangement and the number of the fixed magnetic magnets 2021 and the variable magnetic magnets 2022 may be used without any limitation.

  Next, the operation of the permanent magnet type rotating electrical machine 1 according to the third embodiment will be described. FIG. 9 shows a case where the number of poles of the rotor 20 is 14. The arrows in FIG. 9 indicate the polarities of the poles of the rotor 20. Each variable magnetic magnet 2022 is magnetized by the action of the armature winding 102. The number of poles of the rotor 20 is 14 poles due to the magnetization of each variable magnetic force magnet 2022. At this time, the inverter 30 applies an alternating current to each armature winding 102 in the phase order of the U phase, the V phase, and the W phase as in the case of the A pole in FIG. The AC current applied to each armature winding 102 is shown in FIG. 7 as U (corresponding to U phase), V (corresponding to V phase), -V (corresponding to -V phase), W (corresponding to W phase). , -W (corresponding to -W phase).

  FIG. 10 shows a case where the number of poles of the rotor 20 is 10. The arrows in FIG. 10 indicate the polarities of the poles of the rotor 20. Each variable magnetic magnet 2022 is magnetized by the action of the armature winding 102. The number of poles of the rotor 20 is reduced from 14 poles to 10 poles by reversing the magnetization direction of each variable magnetic force magnet 2022. Note that the inverter 30 applies an alternating current to each armature winding 102 in the order of the U phase, the W phase, and the V phase in accordance with the change in the number of poles of the rotor 20 as in the case of the B pole in FIG. Switch to apply. The AC current applied to each armature winding 102 is shown in FIG. 8 as U (corresponding to U phase), -U (corresponding to -U phase), W (corresponding to W phase), -W (corresponding to -W phase). Corresponding), V (corresponding to the V phase), and -V (corresponding to the -V phase).

  In the third embodiment, the number of slots of the stator slot 1012 is (10 poles + 14 poles) / 2 = 12 slots when the number of poles of the rotor 20 is variable between 10 poles and 14 poles. Although the example formed in 101 has been described, this can be generalized as follows. In other words, when the number of poles of the rotor 20 is variable between 10 n poles and 14 n poles, the number of slots of the stator slots 1012 may be formed in the stator core 101 with (10 n poles +14 n poles) / 2 = 12 n slots. . Note that n is an integer.

  According to the second embodiment, as described in the first embodiment, when the number of poles of the rotor 20 is 10 n poles, compared to the case where the number of poles of the rotor 20 is 14 n poles, The period becomes ½, and the amplitude of the counter electromotive voltage generated by the permanent magnet 202 is halved. According to the second embodiment, the same effects as described in the second embodiment can be obtained.

(Fourth embodiment)
In the first to third embodiments, the arrangement of the fixed magnetic magnet 2021 and the variable magnetic magnet 2022 in the rotor core 201 is particularly limited as long as the number of poles of the rotor 20 is variable to two different pole numbers. However, in the fourth embodiment, an example of a method for determining the arrangement of the fixed magnetic magnet 2021 and the variable magnetic magnet 2022 in the rotor core 201 will be described. In addition, the same code | symbol is attached | subjected to the structure same as 1st-3rd embodiment, and description is abbreviate | omitted.

  FIG. 11 is a graph showing the relationship between the no-load counter electromotive force and the electrical angle in the permanent magnet type rotating electrical machine 1 in which the number of poles of the rotor 20 described in the third embodiment is variable to 14 and 10 as an example. is there. The number of poles A shown in FIG. 11 is a case where the number of poles of the rotor 20 is 14, and the number of poles B is a case where the number of poles of the rotor 20 is 10. Note that the position of the central axis of an arbitrary pole having a polarity from the rotor 20 toward the stator 10 is an electrical angle of 0 °. FIG. 11 shows the permanent magnets 202 arranged in the circumferential direction of the rotor 20 so as to be associated with the electrical angle, below the graph of electrical angle vs. no-load back electromotive force. FIG. 11 shows the magnetization directions of the permanent magnets 202 with arrows when the number of poles of the rotor 20 is A pole and B pole. Since each permanent magnet 202 is arranged in the circumferential direction of the rotor core 201 as shown in FIG. 9 or FIG. 10, when the number of poles of the rotor 20 is A pole (14 poles), One pole is formed by five permanent magnets 202. On the other hand, when the number of poles of the rotor 20 is the B pole (10 poles), one pole is formed by seven permanent magnets 202.

  The hatched portion in FIG. 11 indicates a position where the positive and negative of the A pole back electromotive voltage waveform and the B pole back electromotive voltage waveform are reversed. That is, the magnetization direction of the permanent magnet 202 included in the hatched portion differs depending on the number of poles A and the number of poles B. Therefore, the variable magnetic force magnet 2022 is disposed at the circumferential position of the rotor 20 corresponding to the shaded portion. Conversely, a fixed magnetic magnet 2021 is disposed at a circumferential position of the rotor 20 corresponding to a portion other than the shaded portion. Note that FIG. 11 shows only the no-load counter electromotive voltage waveform up to an electrical angle of 900 °, but the waveform after the electrical angle of 900 ° is the same and is omitted. When the number of poles of the rotor 20 is changed from the A pole to the B pole (or from the B pole to the A pole), the permanent magnet type rotating electrical machine 1 has the armature winding as described in the first to third embodiments. The polarity of the variable magnetic magnet 2022 may be changed by the action of the line 102.

  In the fourth embodiment, an example in which 70 permanent magnets 202 are arranged in the circumferential direction of the rotor core 201 and 7 or 5 permanent magnets 202 form one pole has been described. The total number of permanent magnets 202 arranged in the circumferential direction is not limited to this. That is, if one or more variable magnetic magnets 2022 are arranged in the hatched portion in FIG. 11, the total number of permanent magnets 202 arranged in the circumferential direction of the rotor core 201, the fixed magnetic magnet 2021, and the variable magnetic magnet 2022, respectively. The number of is not limited.

  According to 4th Embodiment, there exists an effect similar to the effect demonstrated in 1st-3rd embodiment. Furthermore, according to the fourth embodiment, the combination of the number of poles can be freely selected, and the number of permanent magnets 202 arranged on the rotor core 201 can be freely selected without having to be adjusted by the combination of the number of poles.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 1 ... Permanent magnet type rotary electric machine, 10 ... Stator, 20 ... Rotor, 30 ... Inverter, 50 ... Inverter control part, 101 ... Stator iron core, 102 ... Armature winding, 201 ... Rotor iron core, 202 ... Permanent Magnets, 1011, stator teeth, 1012, stator slots, 2011, insertion holes, 2021, fixed magnetic magnets, 2022, variable magnetic magnets.

Claims (7)

A stator having electromagnetic windings;
A rotor having a rotor core and a permanent magnet embedded in the rotor core;
Switching the phase sequence of the armature winding without changing the connection of the armature winding,
A permanent magnet type rotating electrical machine that changes the polarity of the permanent magnet by a magnetic field formed by energizing the armature winding, and changes the number of poles of the rotor ,
A first no-load back electromotive voltage when the number of poles of the rotor is the first number of poles and a second when the number of poles of the rotor is a second number of poles less than the first number of poles. When the first no-load back electromotive voltage is changed from positive to negative when the center of the pole of the same polarity as the starting point is compared along the circumferential direction of the rotor, The second no-load back electromotive voltage from the zero cross point where the second no-load back electromotive voltage changes from positive to negative and from the zero cross point where the first no-load back electromotive voltage changes from negative to positive. Between the negative and positive zero cross point, the permanent magnet has a different polarity,
Permanent magnet type rotating electric machine . The permanent magnet includes a variable magnetic magnet,
The permanent magnet type rotating electrical machine according to claim 1, wherein the number of poles of the rotor changes based on a change in polarity of the variable magnetic force magnet.   The permanent magnet type rotating electric machine according to claim 2, wherein when the number of poles of the rotor is A pole or B pole, the number of slots of the stator is (A + B) / 2.   The permanent magnet rotating electrical machine according to claim 3, wherein when the number of poles of the rotor is 2n poles (n is an integer) or 4n poles, the number of slots of the stator is 3n slots.   The permanent magnet type rotating electrical machine according to claim 3, wherein when the number of poles of the rotor is 8n poles (n is an integer) or 10n poles, the number of slots of the stator is 9n slots.   The permanent magnet rotating electrical machine according to claim 3, wherein when the number of poles of the rotor is 10n poles (n is an integer) or 14n poles, the number of slots of the stator is 12n slots.   The permanent magnet type rotating electrical machine according to any one of claims 2 to 6, wherein the variable magnetic force magnet is disposed at a position where the positive / negative of the no-load counter electromotive voltage waveform due to the different number of poles of the rotor is reversed.

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