JP5412121B2 - Permanent magnet rotor and electric motor equipped with the same - Google Patents

Description

  The present invention relates to a permanent magnet rotor including a rotor auxiliary coil that can be easily wound and an electric motor including the same, and a permanent magnet rotor capable of improving output torque while reducing no-load iron loss and the same. It is related with the electric motor provided with.

  Conventionally, an excitation coil is provided on the rotor side, and the field magnetic flux is controlled by the magnetic flux generated by an excitation coil (auxiliary coil) excited as necessary in addition to the magnetic flux generated by a plurality of permanent magnets composed of an N pole group and an S pole group Variable motors have been proposed.

  Examples of such a variable motor include an excitation coil that is wound so as to directly enclose or surround each permanent magnet (see, for example, Patent Documents 1 and 2), U-shaped permanent magnets, which are S poles, are arranged on the rotor so that the same poles are alternately opposed, and a magnetic path is provided between the magnetic poles of the two permanent magnets on the extension line of the core of the exciting coil (For example, see Patent Document 3).

JP 2007-300787 A Special table 2004-519999 gazette JP-A-5-304752

  However, in the variable motor disclosed in Patent Document 1 or 2, there is a problem that the winding length becomes long because the exciting coil is wound around all the permanent magnets. Further, it may be difficult to reduce the size of the variable motor due to the shape of the permanent magnet, the winding, or the like.

  Moreover, since the variable motor disclosed in Patent Document 3 uses a U-shaped permanent magnet, it is necessary to provide a gap between the magnetic poles. In this case, there is a problem that the permanent magnet may be damaged due to a change in the gap between the magnetic poles during operation of the variable motor. Moreover, since the U-shaped permanent magnet is used, there is a problem that the cost of the permanent magnet increases.

  Further, in a variable motor having such an excitation coil, electric power necessary for the excitation coil is supplied in a high-load operation region in order to supplement the output torque of the variable motor. Since this electric power causes loss such as copper loss, it is desirable to reduce the supplied power as much as possible.

  The present invention has been made in view of the above-described points, and its object is to provide a rotor auxiliary coil that can be easily wound, and to improve output torque at low power while reducing no-load iron loss by reducing the amount of magnets. An object of the present invention is to provide a permanent magnet rotor that can be made to operate and an electric motor including the same.

In order to solve the above problems, the permanent magnet type rotor of the present invention (2 ') is on the surface of the rotor yoke facing the stator (3) (21), a plurality of permanent magnets made of one of the two polarities In the permanent magnet rotor (2 ′) in which the magnetic pole portions constituted by the groups (22A, 22B) are arranged so that the polarities are alternated at predetermined intervals in the circumferential direction, the rotor yoke (21) is cylindrical. And a plurality of the magnetic pole portions protruding from the annular portion to the outer diameter side at predetermined intervals in the circumferential direction, and the permanent magnet group (22A) of each of the magnetic pole portions. Or 22B) includes a plurality of permanent magnet pieces (221 or 222) each having the same polarity, and the permanent magnet pieces are arranged with the annular portion as a back yoke, and are adjacent to each other of the two magnetic pole portions having different polarities. the annulus between An auxiliary coil for generating a magnetic flux (40) with wound toroidally over the outer peripheral surface from the inner peripheral surface of the annular portion, in each magnetic pole portion, between the permanent magnet pieces of the same polarity adjacent (221, 222) In the gap, an auxiliary iron core (23) for passing the magnetic flux of the auxiliary coil (40) is provided so as to fill the gap, and the two auxiliary coils (40) adjacent in the circumferential direction face each other. The magnetic poles are wound so that the magnetic poles on the side are the same .

According to the permanent magnet type rotor of the present invention, the rotor auxiliary coil does not need to surround the permanent magnet as disclosed in Patent Documents 1 and 2, and the auxiliary coil is wound around the rotor yoke in a toroidal shape. Can be easily wound. Further, unlike the configuration of the electric motor disclosed in Patent Document 3 described above, the permanent magnet back yoke and the magnetic path of the auxiliary coil can be shared , that is, the annular portion which is the permanent magnet back yoke is supported. Since it can function as a magnetic path of the coil, it is not necessary to use a U-shaped permanent magnet or to provide a gap between the magnetic poles of the two permanent magnets. Furthermore, since the magnetic resistance of the auxiliary iron core provided so as to fill the gap between adjacent permanent magnet pieces in the magnetic pole part is smaller than that of, for example, a permanent magnet, this auxiliary iron core can be used as the magnetic path of the auxiliary coil. , thereby, the auxiliary coil can be TeiOkoshi magnetic force. Furthermore, since the two auxiliary coils adjacent in the circumferential direction are arranged so that the magnetic poles on the opposite side are the same pole, the magnetic flux generated by the permanent magnet piece is used as the field magnetic flux of the auxiliary coil. In addition, since the auxiliary iron core can be used as the magnetic path of the auxiliary coil as described above, the magnetic flux generated by the permanent magnet piece is supplemented (assisted) by the field magnetic flux of the auxiliary coil. In this case, since the auxiliary iron core having a smaller magnetic resistance than the permanent magnet is used as the magnetic path of the auxiliary coil, the auxiliary coil can be made low in magnetomotive force and the loss in the auxiliary coil can be reduced.

  In the permanent magnet type rotor of the present invention, a fixing member (24) made of a nonmagnetic material having a substantially U-shaped cross section for covering and fixing each of the permanent magnet pieces (221, 222) is provided. 24) may be fixed by fitting both end portions (24a) to the rotor yoke (21). Alternatively, a fixing member (24) made of a nonmagnetic material having a substantially L-shaped cross section for wrapping and fixing each of the permanent magnet pieces (221, 222) is provided, and the fixing member (24) is an auxiliary iron core (23 ) And the rotor yoke (21) may be fixed by fitting both end portions (24a, 24b) thereof. Thus, by providing the fixing member made of a non-magnetic material so as to wrap each permanent magnet piece, the magnetic flux generated from the permanent magnet piece and the auxiliary coil does not pass through the fixing member, but in the gap between the adjacent permanent magnet pieces. It will pass through the provided auxiliary iron core intensively. Therefore, since the magnetic flux of the permanent magnet piece and the magnetic flux of the auxiliary coil pass through the auxiliary iron core in a concentrated manner, the leakage magnetic flux can be reduced.

  In the permanent magnet rotor of the present invention, the side surfaces of the auxiliary iron core (23) or the rotor yoke (21) are provided with fitting grooves (23a, 21a), and both end portions (24a) of the fixing member (24) are What is necessary is just to be the convex shape fitted to the fitting groove | channel (23a, 21a) of an auxiliary iron core (23) or a rotor yoke (21). Thus, since the fixing member is configured to be fitted to the rotor yoke or the auxiliary iron core, the permanent magnet piece can be firmly fixed to the rotor yoke.

  In order to solve the above problems, the electric motor (1 ′) of the present invention is in contact with the permanent magnet rotor (2 ′) and the permanent magnet rotor (2 ′) as described above. In the electric motor (1 ′) including the stator (stator) (3) to be arranged, in the low load operation region (A) of the electric motor (1 ′), each permanent magnet piece (22A, 22B) ( 221 and 222), and in the high load operation region (B), the current required for the auxiliary coil (40) according to the rotor magnetic flux that is insufficient with only the magnetic flux of these permanent magnet pieces (221 and 222). It is characterized by operating by energizing a quantity (ampere turn).

  According to the electric motor of the present invention, since the field magnetic field of the auxiliary coil can be used during high load operation of the electric motor, the torque of the electric motor can be improved without increasing the total amount of permanent magnet pieces. Thereby, the no-load iron loss of an electric motor can be reduced compared with the case where an auxiliary coil is not used. In addition, since the back electromotive force can be reduced, the motor itself and the inverter for the motor can be reduced in size, and the efficiency of the motor can be increased.

  In the electric motor of the present invention, the amount of current that flows through the auxiliary coil (40) due to the difference between the torque command value for the electric motor (1 ') and the torque threshold value corresponding to the magnetic flux of the permanent magnet group (22A, 22B). What is necessary is just to adjust (current amount of field current). As described above, the relationship between the torque command value and the amount of current (ampere turn) energized to the auxiliary coil is obtained in advance by analysis or experiment, so that the motor of the present invention can be appropriately operated at a high load. Can do.

  The reference numerals in the parentheses described above exemplify corresponding constituent elements in the embodiments described later for reference.

According to the present invention, the auxiliary coil can be easily wound around the rotor yoke, and the fixing member made of a nonmagnetic material for fixing the permanent magnet piece is provided, and the field magnetic flux of the auxiliary coil concentrates the auxiliary iron core. By configuring so as to pass through the motor, the output torque of the electric motor can be improved with low power. Moreover, the no-load iron loss of an electric motor can be reduced by reducing the total amount of permanent magnet pieces. Furthermore, since the two auxiliary coils adjacent in the circumferential direction are arranged so that the magnetic poles on the opposite side are the same pole, the magnetic flux generated by the permanent magnet piece is used as the field magnetic flux of the auxiliary coil. In addition, when the auxiliary iron core can be used as the magnetic path of the auxiliary coil, the magnetic flux generated by the permanent magnet piece is supplemented (assisted) by the field magnetic flux of the auxiliary coil. Since the auxiliary iron core having a smaller magnetic resistance than the permanent magnet is used as the magnetic path of the auxiliary coil, the auxiliary coil can be reduced in magnetomotive force, and loss in the auxiliary coil can be reduced.

It is a conceptual diagram of the electric motor containing a permanent magnet type | mold rotor, (a) is the fragmentary perspective view, (b) is the fragmentary sectional view. It is a notional fragmentary sectional view of the electric motor containing the permanent magnet type rotor of the present invention. It is a block diagram which shows the control system of a magnet magnetic flux, and the control system of an auxiliary coil magnetic flux. It is a circuit diagram which shows an example of the control system of the magnet magnetic flux of FIG. It is a circuit diagram which shows an example of the control system of the auxiliary coil magnetic flux of FIG. It is a graph which shows the torque-rotation speed characteristic of the electric motor in this embodiment. It is a graph which shows the relationship between a torque command value and the ampere-turn of an auxiliary coil. It is a graph which shows the relationship between the torque difference required for torque complement, and the energization amount of the auxiliary coil corresponding to it. It is a flowchart which shows the motor driving | running process of the electric motor of this embodiment. It is a figure which shows the result of the torque magnetic field analysis of the electric motor shown to FIG. 1 and FIG.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of a permanent magnet rotor and an electric motor including the same according to the invention will be described in detail with reference to the accompanying drawings. The permanent magnet rotor according to the present invention is used as a rotor (rotor) of an electric motor mounted on a vehicle such as an electric vehicle or a so-called hybrid vehicle, and drives the vehicle by output torque generated by the electric motor. In the present invention, the configuration (structure, control method, etc.) of the permanent magnet type rotor has its technical characteristics, and therefore other components of the vehicle (for example, the drive system, etc.) are not shown in the drawings. Detailed description thereof is omitted.

  First, with reference to FIG. 1 and FIG. 2, the structure of the permanent magnet type rotor which concerns on this invention, and an electric motor provided with the same is demonstrated in detail. FIG. 1 is a conceptual diagram of an electric motor including a permanent magnet type rotor that is a basic configuration of the present invention. FIG. 1 (a) is a partial perspective view thereof, and FIG. 1 (b) is a partial sectional view thereof. As will be described later, the permanent magnet rotor 2 and the electric motor 1 including the same shown in FIG. 1 have the basic configuration of the present invention.

  First, the structure of the electric motor 1 provided with the permanent magnet type rotor 2 shown in FIG. 1 is demonstrated. As shown in FIGS. 1A and 1B, the electric motor 1 has an inner rotor type permanent magnet rotor (hereinafter also referred to as “rotor”) 2 and an outer periphery of the permanent magnet rotor 2. And a stator (hereinafter also referred to as “stator”) 3 provided so as to be in contact therewith.

  The stator 3 includes a stator core 31 that constitutes the outer periphery of the electric motor 1 and a plurality of protrusions protruding from the stator core 31 inward in the radial direction, that is, toward the center of the rotor 2 (in the present embodiment, the entire illustration is omitted, For example, 18 teeth 32. Each tooth 32 includes a tooth tip portion 32a and a winding portion 32b (constituting an iron core of the stator coil 33) around which the stator coil 33 is wound. The plurality of teeth 32 are arranged at equal intervals in the circumferential direction of the stator 3, and the tooth tip 32 a of each tooth 32 is formed so as to protrude from the tip of the tooth 32 in the circumferential direction.

  The rotor 2 includes a rotor core (rotor yoke) 21 and N-pole and S-pole permanent magnet pieces 22 a and 22 b that are alternately arranged on the outer circumference of the rotor core 21 at equal intervals in the circumferential direction. In the rotor core 21, a rotor auxiliary coil (or excitation coil, hereinafter referred to as “auxiliary coil”) 40 is wound in a toroidal shape between adjacent permanent magnet pieces 22 a and 22 b. The auxiliary coil 40 generates a field magnetic flux for assisting the output torque under a predetermined condition. Thus, the auxiliary coil 40 can be wound directly on the rotor core 21 in a toroidal shape, so that the auxiliary coil 40 can be easily wound. Further, since the back yokes of the permanent magnet pieces 22a and 22b and the magnetic path of the auxiliary coil 40 can be shared, a conventional U-shaped permanent magnet is used, or a gap is formed between the magnetic poles of the two permanent magnets. There is no need to set up.

  Here, for example, in the two auxiliary coils 40 adjacent to each other in the circumferential direction shown in FIG. 1B, the permanent magnet piece 22a provided between them is an N pole. The magnetic poles of the auxiliary coils 40 facing the N pole of the piece 22a are wound so as to become the N pole, that is, the same pole when energized. Similarly, in the two auxiliary coils 40 adjacent to each other with the S-pole permanent magnet piece 22b provided therebetween, the magnetic poles of the auxiliary coils 40 facing the S-pole of the permanent magnet piece 22b become the S-pole when energized. So that it is wound. In the present embodiment, by arranging the adjacent auxiliary coils 40 in this way, the magnetic flux generated by the permanent magnet pieces 22a and 22b can be supplemented (assisted) by the field magnetic flux of the auxiliary coil 40.

  As shown in FIG. 1A, a non-contact (non-contact) energization type rotor transformer 50 is provided on the rotor 2 side. In the rotor transformer 50, a power supply coil 51 connected to a control power supply 9 to be described later and supplied with AC power from the control power supply 9 and a power receiving coil 52 supplied with power from the AC power supply applied to the power supply coil 51 are provided. It is done. The feeding coil 51 and the receiving coil 52 are adjacent to each other, but there is no contact point. Although not shown in FIG. 1A, the power receiving coil 52 is connected in series with the auxiliary coil 40 as will be described later.

  In the present embodiment, since the auxiliary coil 40 is wound around the rotor core (rotor yoke) 21 of the inner rotor type permanent magnet rotor 2 in a toroidal shape, the control current (excitation current) to the auxiliary coil 40 is controlled. Is provided on the rotor 2 side, that is, on the side close to the center of the electric motor 1. The present invention is not limited to such an inner rotor type, and the permanent magnet rotor 2 may be an outer rotor type permanent magnet rotor. In this case, the rotor transformer 50 may be provided on the outer rotor side, that is, on a portion close to the outer periphery of the electric motor 1.

  Next, with reference to FIG. 2, the structure of the permanent magnet type | mold rotor of this invention and an electric motor provided with the same is demonstrated. FIG. 2 is a conceptual partial cross-sectional view of an electric motor including the permanent magnet type rotor of the present invention. An electric motor 1 ′ shown in FIG. 2 includes permanent magnet groups 22A and 22B each made up of a plurality of permanent magnet pieces 221 and 222 instead of the permanent magnet pieces 22a and 22b. 22A and 22B differ from the electric motor 1 shown in FIG. 1 in that an auxiliary iron core 23 is provided between adjacent permanent magnet pieces 221 and 221 (not shown, but the same applies to the permanent magnet pieces 222 and 222). . Here, the components different from the configuration of the electric motor 1 shown in FIG. 1 will be described in detail, and the same components as those of the electric motor 1 are denoted by the same reference numerals and the description thereof is omitted.

  As shown in FIG. 2, the electric motor 1 ′ of this embodiment has an inner rotor type permanent magnet rotor (hereinafter also referred to as “rotor”) 2 ′ and an outer periphery of the permanent magnet rotor 2 ′. And a stator (hereinafter also referred to as “stator”) 3 provided so as to be in contact therewith. Since the configuration of the stator 3 is the same as that of the electric motor 1 of FIG. Hereinafter, the configuration of the rotor 2 ′ will be mainly described in detail.

  In the present embodiment, each magnetic pole constituting the N pole is provided with a permanent magnet group 22A composed of two permanent magnet pieces 221 and 221 as shown in FIG. Similarly, each magnetic pole constituting the S pole is provided with a permanent magnet group 22B composed of two permanent magnet pieces 222 and 222, although only one is shown in FIG. 2 illustrates the case where each of the permanent magnet groups 22A and 22B includes two permanent magnet pieces 221 and 222. However, the present invention is not limited to such a configuration, and the auxiliary iron core 23 includes the stator coil 33. Each permanent magnet group 22A, 22B may be composed of three or more permanent magnet pieces 221, 222 as long as it is spatially arranged substantially in series with the inner winding portion (iron core) 32b.

  An auxiliary iron core 23 is provided in a gap between adjacent (adjacent) permanent magnet pieces 221, 221 and 222, 222 of each permanent magnet group 22A, 22B so as to fill the gap. The auxiliary iron core 23 functions as an auxiliary coil magnetic path for passing the magnetic flux generated by the auxiliary coil 40. Therefore, the auxiliary iron core 23 is made of a material having a high magnetic permeability (that is, a small magnetic resistance) as compared with a fixing member 24 and air described later. As shown in FIG. 2, the auxiliary iron core 23 may be configured integrally with the rotor core 21 so as to protrude from the rotor core 21. As long as the auxiliary iron core 23 is fixed to the rotor core 21, it is separate from the rotor core 21. It may be configured as.

  Around each permanent magnet piece 221, 222, magnetic flux generated from the permanent magnet piece 221, 222 passes through at least one direction (here, the direction in which one surface of the permanent magnet pieces 221, 222 abuts the stator 3). A fixing member 24 for wrapping and fixing the permanent magnet pieces 221 and 222 is provided. In this embodiment, the shape of each permanent magnet piece 221 and 222 is substantially a rectangular parallelepiped. As shown in FIG. 2, the fixing member 24 has a substantially U-shaped cross section so that the fixing member 24 covers at least three of the six surfaces constituting the rectangular parallelepiped. By providing such a fixing member 24, leakage of magnetic flux to be induced in the stator coil 33 can be effectively reduced.

  The fixing member 24 is fixed by fitting at least one end to the rotor core 21 in its cross section. Specifically, in the cross section of the fixing member 24, as shown in FIG. 2, a fixing portion (a dowel) 24 a for fixing the fixing member 24 to the rotor core 21 is provided at one end portion of the fixing member 24. . On the other hand, a fitting groove 21 a that fits into the fixing portion 24 a of the fixing member 24 is provided near the outer peripheral surface of the rotor core 21.

  In addition, the fixing member 24 is a fitting provided on the side surface of the auxiliary iron core 23 at a predetermined position on the surface of the fixing member 24 that faces the surface where the fixing portion 24a is provided via the permanent magnet pieces 221 and 222. A fixing portion 24b for fitting into the groove 23a is provided. These fixing portions 24a and 24b are not substantially spherical (or hemispherical) for fixing to the rotor core 21 or the auxiliary iron core 23 at one point, but are substantially cylindrical or substantially cylindrical extending in a direction perpendicular to the paper surface of FIG. is there. With such a configuration, the fixing member 24 is slid perpendicularly to the paper surface of FIG. 2 and inserted into the rotor core 21 and the auxiliary iron core 23 provided with the fitting grooves 21a and 23a, respectively. The permanent magnet rotor 2 ′ can be easily assembled.

  The fixing member 24 is made of a nonmagnetic material such as stainless steel (SUS). Therefore, the magnetic flux from the permanent magnet pieces 221 and 222 and the magnetic flux generated by the auxiliary coil 40 do not pass through the fixing member 24, and the auxiliary iron core 23 provided in the gap between the adjacent permanent magnet pieces 221, 221 and 222, 222 is used. Pass through intensively. Therefore, since the magnetic flux of the permanent magnet pieces 221 and 222 and the magnetic flux of the auxiliary coil 40 are concentrated and passed through the auxiliary iron core 23, the leakage magnetic flux can be reduced as described above.

  In the present invention, the configuration (structure) of the fixing member 24 is not limited to the configuration described above, and may be as follows, for example. That is, the fixing member 24 has a substantially U-shaped cross section like the fixing member 24 of FIG. 2, but both end portions in the cross section have the same configuration as the fixing portion 24a of FIG. May be. Alternatively, the fixing member 24 has a substantially L-shaped cross section, and both end portions thereof are fitted in fitting grooves 21 a and 23 a provided on the outer peripheral surface of the rotor core 21 and the side surfaces of the auxiliary iron core 23, respectively. It may be a configuration. Even with such a configuration, the permanent magnet pieces 221 and 222 can be fixed by the fixing member 24, and leakage of magnetic flux generated from the permanent magnet pieces 221 and 222 and the auxiliary coil 40 can be reduced.

  In addition, compared with the case where the fixing | fixed part (dowel) 24b as shown in FIG. 2 is provided corresponding to the side surface of the auxiliary iron core 23, or the cross-sectional shape of the fixing member 24 is substantially L-shaped, the fixing | fixed part ( The dowels 24a are preferably provided at both ends of the cross section corresponding to the outer peripheral surface of the rotor core 21. In this case, the permanent magnet pieces 221 and 222 can be firmly fixed, and the magnetic path of the auxiliary iron core 23 through which the generated magnetic flux passes can be made wider.

  Next, with reference to FIGS. 3 to 5, the exciting current supply system for the permanent magnet rotor 2 ′ of the present embodiment and the electric motor 1 ′ including the same will be described in detail. FIG. 3 is a block diagram showing a magnet magnetic flux control system and an auxiliary coil magnetic flux control system. 4 is a circuit diagram showing an example of the magnet magnetic flux control system of FIG. 3, and FIG. 5 is a circuit diagram showing an example of the auxiliary coil magnetic flux control system of FIG.

  As shown in FIG. 3, in the exciting current supply system of the present embodiment, when the operation unit 6 of the vehicle is operated by the driver, here, for example, when an accelerator pedal (not shown) is depressed, the operation amount (depression) A detection signal is sent from the operation amount detector 61 to an electronic control unit (hereinafter referred to as “ECU (Electric Control Unit)”) 7 in accordance with the amount, for example, the accelerator pedal opening degree.

  The ECU 7 is based on input signals from various sensors and instruments (not shown) including the operation amount detection unit 61 and the like, and is also referred to as a PDU (Power Drive Unit) 8, a traveling motor (hereinafter also referred to as “electric motor”). 1) Control the control power supply 9 for the auxiliary coil 40 and the like. In particular, the ECU 7 calculates a torque command value corresponding to the rotation speed of the rotor 2 ′ based on a detection signal from the operation amount detection unit 61, and outputs the calculated torque command value to the PDU 8.

  As shown in FIG. 4, the PDU 8 is connected to a high voltage battery 85 that exchanges electric energy with the electric motor 1 ′. In this embodiment, the PDU 8 includes a PWM inverter IN that performs pulse width modulation (PWM) using a bridge circuit in which transistor switching elements 81a to 83b are bridge-connected, and a capacitor 84 that is connected in parallel to the PWM inverter IN. And controlling the driving operation and the regenerative operation of the electric motor 1 ′ in accordance with a control command output from the ECU 7.

  The PWM inverter IN responds to a torque command value (drive torque value) input from the ECU 7, for example, when driving the electric motor 1 ′, for example, a gate signal (that is, pulse width modulation) that is a switching command input from the ECU 7. The DC power supplied from the battery 85 is changed to the three-phase AC power by switching the on (conductive) / off (cut) state of the switching elements 81a to 83b paired for each phase of the PWM inverter IN based on the signal). Convert to Then, by sequentially commutating energization to each stator coil (stator winding) 33 of the stator 3 of the electric motor 1 ′, AC U-phase current Iu, V-phase current Iv and A W-phase current Iw is applied. As a result, the PDU 8 causes the electric motor 1 ′ to generate a torque corresponding to the torque command value. For example, when the electric motor 1 ′ is regenerated, the PDU 8 converts the three-phase AC power output from the electric motor 1 ′ into DC power and charges the battery 85.

  Here, when the torque command value is equal to or less than the threshold value of the torque with respect to the rotational speed of the rotor 2 ′ as shown in FIG. 6 (that is, the low-load operation region A), the ECU 7 The electric motor 1 ′ is operated only with the magnetic fluxes of the permanent magnet pieces 221 and 222 of 22A and 22B. However, when the torque command value exceeds the threshold value shown in FIG. 6 (that is, the high load operation region B), the ECU 7 controls the auxiliary coil 40 to cope with the difference between the torque command value and the threshold value. The power supply 9 is instructed to energize the auxiliary coil 40. Thereby, in the high load operation region B of the electric motor 1 ′, the ECU 7 sets the control power source 9 so as to supplement the magnetic field flux generated by energizing the auxiliary coil 40 in addition to the magnetic flux of the permanent magnet pieces 221 and 222. Control. As a result, since the field magnetic field of the auxiliary coil 40 can be used during high load operation of the electric motor 1 ′, the electric motor 1 ′ can be used without increasing the total amount of the permanent magnet pieces 221 and 222 of the permanent magnet groups 22A and 22B. The torque can be improved. Therefore, compared with the case where the auxiliary coil 40 is not used, the no-load iron loss of the electric motor 1 ′ can be reduced. Moreover, since the back electromotive force can be reduced, the motor 1 ′ itself and the inverter for the motor 1 ′ can be reduced in size, and the efficiency of the motor 1 ′ can be increased.

FIG. 6 is a graph showing the torque-rotational speed characteristics of the electric motor 1 ′ in the present embodiment, and this torque is a magnetic flux obtained from the rotational speed of the rotor 2 ′ and the maximum current supplied to the electric motor 1 ′. Torque. In the present embodiment, the torque-rotational speed characteristic is constant in the region where the rotational speed of the rotor 2 ′ is between ₀ and the predetermined rotational speed N ₀ , and is constant at a higher speed than the predetermined rotational speed N _0. It has the characteristic that it becomes output.

  As shown in FIG. 5, the control power supply 9 includes a bridge circuit (switching circuit) 90 in which switching elements 91 of four transistors are bridge-connected. The control power supply 9 is connected to a low-voltage (for example, 12 V) battery 92 for supplying electric energy to the auxiliary coil 40.

  In the present embodiment, the low-voltage battery 92 may be a DC power source capable of applying a DC voltage to the switching circuit 90, and for example, to supply a three-phase AC current to the electric motor 1 'via the PDU 8. It may be shared with the high-voltage battery 85. In this case, the high voltage battery 85 can be used as a battery for the auxiliary coil 40 by reducing the voltage to the voltage required for the auxiliary coil 40 by the rotor transformer 50.

  The switching circuit 90 controls the energization amount of the direct current supplied to the auxiliary coil 40 according to the difference between the torque command value input from the ECU 7 and the threshold value. Here, FIG. 7 is a graph showing the relationship between the torque command value (Nm) and the energization amount (ampere-turn: AT) to the auxiliary coil 40, and FIG. 8 shows the torque difference (Nm) required for torque complementation. It is a graph which shows the relationship between the energization amount (AT) of the auxiliary coil 40 corresponding to it.

  The ECU 7 outputs a gate signal that is a switching command of each switching element 91 of the switching circuit 90 based on the differential torque between the torque command value and the threshold value and the graphs of FIGS. The switching circuit 90 switches DC power supplied from the battery 92 to a single phase by switching the on (conductive) / off (cut) state of each switching element 91 based on the gate signal (that is, the pulse width modulation signal). Convert to AC power. The converted single-phase AC power is transformed by the rotor transformer 50 in accordance with the turn ratio between the feeding coil 51 and the receiving coil 52 and the partial coil up to the intermediate point X of the receiving coil 52, and the transformed AC power is converted into a diode. The rectified current by the group 11 and an ampere-turn DC current corresponding to the differential torque between the torque command value and the threshold value is supplied to the auxiliary coil 40. When a direct current is supplied to the auxiliary coil 40, a field magnetic flux is generated in the auxiliary coil 40 according to the amount of current (AT), and the generated magnetic flux is an auxiliary iron core provided in the S-pole permanent magnet group 22B. 23 passes through the auxiliary iron core 23 provided in the N-pole permanent magnet group 22A, is supplied to the iron core of the stator coil 33, and finally the electric motor 1 'generates a complementary torque. As described above, the relationship between the torque command value output from the ECU 7 and the amount of current (ampere turn) supplied to the auxiliary coil 40 with respect to the complementary torque is obtained in advance by analysis or experiment, whereby the electric motor 1 of the present invention is obtained. It is possible to appropriately perform operation at high load on '.

  Next, motor operation processing of the electric motor 1 ′ of the present embodiment will be described using a flowchart. FIG. 9 is a flowchart showing a motor operation process of the electric motor 1 ′ of the present embodiment. When the operation unit 6 of the vehicle is operated by the driver, the operation amount detection unit 61 detects the operation amount of the operation unit 6 (step S1), and outputs the detected operation amount to the ECU 7. The ECU 7 that has received the detected operation amount calculates, as a torque command value, the torque that should be output by the electric motor 1 ′ in accordance with the operation amount (step S2).

  Next, the ECU 7 determines whether or not the torque command value is larger than a torque threshold value with respect to the rotational speed of the rotor 2 ′ as shown in FIG. 6 (step S3). When it is determined that the torque command value is larger than the threshold value, the ECU 7 calculates the amount of current to be supplied to the auxiliary coil 40 (step S4), and the calculated amount of current is supplied to the auxiliary coil 40. As described above, a gate signal (pulse width modulation signal) for each switching element 91 is output, and the on / off state of each switching element 91 of the switching circuit 90 is switched. Thereby, the ECU 7 converts the DC power of the battery 92 into single-phase AC power, and supplies the necessary amount of current (AT) to the auxiliary coil 40 via the rotor transformer 50. In this way, the electric motor 1 ′ is operated using the field magnetic flux of the auxiliary coil 40 in addition to the magnetic flux of the permanent magnet pieces 221 and 222 of the permanent magnet groups 22A and 22B (step S5). Exit.

  On the other hand, if it is determined in step S3 that the torque command value is not greater than the threshold value, it is not necessary to use the field magnetic flux of the auxiliary coil 40, so that the electric motor 1 'has the permanent magnet pieces 221 and 222. Is operated using only the magnetic flux (step S6), and the motor operation process is terminated.

  In addition, in the electric motor 1 and the electric motor 1 ′ of the present invention that are the basic configuration of the present invention, the output torque when only the magnetic fluxes of the permanent magnet pieces 22a and 22b and the permanent magnet pieces 221 and 222 are used, and the auxiliary An output torque when a field magnetic flux obtained by applying a field current to the coil 40 is further applied is shown as a result of the torque magnetic field analysis. FIG. 10 is a diagram showing the results of torque magnetic field analysis of the electric motors 1 and 1 ′ shown in FIG. 1 and FIG. In this torque magnetic field analysis, as shown in FIG. 10A, in the case where only the magnetic flux of the permanent magnet pieces 22a and 22b in the electric motor 1 is used, the torque is 102 (Nm). A torque of 155 (Nm) was obtained by applying a current amount of 4000 ampere-turns (AT) to the auxiliary coil 40. Therefore, compared to the case of only the magnetic flux of the permanent magnet pieces 22a and 22b, the torque of about 50% can be improved by using the auxiliary coil 40. On the other hand, as shown in FIG. 10B, in the case of only the magnetic flux of the permanent magnet pieces 221 and 222 in the electric motor 1 ′, the torque was 80 (Nm). A torque of 151 (Nm) was obtained by passing a current of 3000 ampere turns (AT) through the auxiliary coil 40. Therefore, compared with the case of only the magnetic flux of the permanent magnet pieces 221, 222, the torque of about 80% can be improved by using the auxiliary coil 40. As described above, the electric motor 1 ′ of the present invention can supplement the torque equivalent to that of the electric motor 1 with a current amount of 3000 ampere-turns, so that the auxiliary coil 40 has a lower magnetomotive force than the electric motor 1. can do. Thereby, losses, such as a copper loss in the auxiliary coil 40, can be reduced.

  As described above, according to the permanent magnet rotor 2 of the present invention, a plurality of permanent magnet groups 22A and 22B made of one of two polarities are alternately arranged at predetermined intervals on the surface of the rotor yoke 21 facing the stator 3. In the permanent magnet type rotor 2 ′ arranged in the above, an auxiliary coil 40 for generating a field magnetic flux is wound between two permanent magnet groups 22A, 22B adjacent to each other in a toroidal shape, and the permanent magnet group 22A, 22B includes a plurality of permanent magnet pieces 221 and 222, respectively, and an auxiliary iron core 23 for passing the magnetic flux of the auxiliary coil 40 is provided in the gap between adjacent permanent magnet pieces 221 and 222 in each permanent magnet group 22A and 22B. It was decided that it would be filled up. Since the auxiliary coil 40 can be directly wound around the rotor yoke 21, the auxiliary coil 40 can be easily wound. Further, since the magnetic resistance of the auxiliary iron core 23 provided so as to fill the gap between the permanent magnet groups 22A and 22B is smaller than, for example, the permanent magnet pieces 221 and 222 and air, the auxiliary iron core 23 is used as the magnetic coil of the auxiliary coil 40. It can be used as a road. Thereby, the auxiliary coil 40 can be made low in magnetomotive force.

  In the permanent magnet rotor 2 ′ of the present invention, a fixing member 24 made of a nonmagnetic material having a substantially U-shaped or substantially L-shaped cross section for wrapping and fixing each of the permanent magnet pieces 221 and 222 is provided. The fixing member 24 is fixed to the rotor 2 ′ by fitting the fixing portion 24 a at the end thereof to the side surface of the rotor core 21 or the auxiliary iron core 23. Thus, by providing the fixing member 24 made of a nonmagnetic material so as to wrap each permanent magnet piece 221, 222, the magnetic flux generated from the permanent magnet pieces 221, 222 and the auxiliary coil 40 does not pass through the fixing member 24. Then, the auxiliary iron core 23 provided in the gap between the adjacent permanent magnet pieces 221 and 222 is intensively passed. Therefore, leakage of magnetic flux generated from the permanent magnet pieces 221 and 222 and the auxiliary coil 40 can be reduced.

  In the permanent magnet rotor 2 'of the present invention, the side surfaces of the auxiliary iron core 23 or the rotor core 21 are provided with fitting grooves 23a, 21a, and the fixing portions 24a, 24b of the fixing member 24 are provided with the auxiliary iron core 23 or The cross section is convex so as to be fitted into the fitting grooves 23 a and 21 a of the rotor yoke 21. Since the fixing member 24 is thus fitted to the rotor core 21 or the auxiliary iron core 23, the permanent magnet pieces 221 and 222 can be firmly fixed to the rotor core 21.

  Further, in the permanent magnet rotor 2 ′ of the present invention, the two auxiliary coils 40 adjacent in the circumferential direction have the same magnetic pole on the opposite side as well as the magnetic pole of the permanent magnet piece 22a or 22b provided therebetween. It suffices to be wound so as to be. By arranging the adjacent auxiliary coils 40 in this manner, the magnetic flux generated by the permanent magnet pieces 22 a and 22 b can be supplemented (assisted) by the field magnetic flux of the auxiliary coil 40.

  Moreover, according to the electric motor 1 ′ of the present invention, the electric motor including the permanent magnet rotor 2 ′ as described above and the stator (stator) 3 disposed so as to contact the permanent magnet rotor 2 ′. In 1 ′, in the low load operation region A of the electric motor 1 ′, the permanent magnet groups 22A and 22B are operated only by the magnetic fluxes of the permanent magnet pieces 221 and 222, and in the high load operation region B, these permanent magnet pieces 221 and 222 are operated. In accordance with the rotor magnetic flux that is insufficient with only the magnetic flux, the current (ampere turn) required for the auxiliary coil 40 is energized for operation. As a result, since the field magnetic field of the auxiliary coil 40 can be used during high load operation of the electric motor 1 ′, the torque of the electric motor 1 ′ can be improved without increasing the total amount of the permanent magnet pieces 221 and 222. it can. Therefore, compared with the case where the auxiliary coil 40 is not used, the no-load iron loss of the electric motor 1 ′ can be reduced. Further, since the back electromotive force can be reduced, the motor 1 ′ itself and the inverter for the motor 1 can be reduced in size, and the efficiency of the motor 1 ′ can be increased.

  Further, in the electric motor 1 ′ of the present invention, the auxiliary value is determined by the difference between the torque command value for the electric motor 1 ′ and the torque threshold value corresponding to the magnetic flux of the plurality of permanent magnet pieces 221 and 222 of the permanent magnet groups 22A and 22B. The amount of current flowing through the coil 40 (the amount of field current: ampere-turn) was adjusted. As described above, the relationship between the torque command value and the amount of current (ampere turn) supplied to the auxiliary coil 40 is obtained in advance by analysis or experiment, so that the operation of the electric motor 1 of the present invention at the time of high load can be appropriately performed. It can be carried out.

  The embodiments of the permanent magnet rotor of the present invention and the electric motor including the same have been described in detail with reference to the accompanying drawings. However, the present invention is not limited to these configurations, and Various modifications can be made within the scope of the technical idea described in the specification and drawings. In addition, even if it has a shape, structure, or function that is not directly described in the specification and drawings, it is within the scope of the technical idea of the present invention as long as it has the effects and advantages of the present invention. That is, each part which comprises an electric motor and a permanent magnet type | mold rotor can be substituted with the thing of the arbitrary structures which can exhibit the same function. Moreover, arbitrary components may be added.

  In the above-described embodiment, the present invention has been described in detail using the inner rotor type electric motor (electric motor) 1 ′. However, the present invention is not limited to the inner rotor type electric motor, and may be an outer rotor type electric motor. Can also be applied.

1, 1 'electric motor (electric motor)
2, 2 'Permanent magnet type rotor (rotor)
21 Rotor core (rotor yoke)
21a Fitting groove 22A, 22B Permanent magnet group 221, 222, 22a, 22b Permanent magnet piece 23 Auxiliary iron core 23a Fitting groove 24 Fixing member 24a, 24b Fixing part (Dowel)
3 Stator (stator)
31 Stator core 32 Teeth 33 Stator coil 6 Operation unit 61 Operation amount detection unit 7 Electronic control unit (ECU)
8 Power Drive Unit (PDU)
81a to 83b Switching element 85 Battery 9 Control power supply 11 Diode group 40 Rotor auxiliary coil 50 Rotor transformer 51 Feeding coil 52 Power receiving coil 90 Switching circuit 91 Switching element 92 Battery IN PWM inverter

Claims (6)

On the surface of the stator facing the rotor yoke, the magnetic pole portion constituted by two of the plurality of permanent magnet groups consisting of either polarity, the permanent magnet rotating arranged so polarity is alternately at predetermined intervals in the circumferential direction In the child
The rotor yoke includes an annular portion having a cylindrical inner peripheral surface, and a plurality of the magnetic pole portions protruding from the annular portion to the outer diameter side at predetermined intervals in the circumferential direction,
The permanent magnet group of each magnetic pole part includes a plurality of permanent magnet pieces each having the same polarity, and the permanent magnet pieces are arranged with the annular part as a back yoke,
An auxiliary coil for generating a field magnetic flux in the annular portion between two magnetic pole portions having different polarities adjacent to each other is wound in a toroidal shape from the inner peripheral surface to the outer peripheral surface of the annular portion ,
In each magnetic pole portion, an auxiliary iron core for passing the magnetic flux of the auxiliary coil is provided in a gap between the adjacent permanent magnet pieces of the same polarity, so as to fill the gap ,
The two auxiliary coils adjacent to each other in the circumferential direction are wound so that the magnetic poles on the opposite side are the same pole .   A fixing member made of a non-magnetic material having a substantially U-shaped cross section for wrapping and fixing each of the permanent magnet pieces is provided, and the fixing member is fixed by fitting both ends of the rotor yoke. The permanent magnet rotor according to claim 1, wherein:   A fixing member made of a non-magnetic material having a substantially L-shaped cross section for wrapping and fixing each of the permanent magnet pieces is provided, and the fixing member is fitted to both sides of the auxiliary iron core and the rotor yoke. The permanent magnet rotor according to claim 1, wherein the permanent magnet rotor is fixed by joining together.   A side surface of the auxiliary iron core or the rotor yoke is provided with a fitting groove, and both end portions of the fixing member have a convex shape that fits into the fitting groove of the auxiliary iron core or the rotor yoke. The permanent magnet type rotor according to claim 2 or 3. The permanent magnet rotor according to any one of claims 1 to 4 ,
In an electric motor comprising a stator disposed so as to abut on the permanent magnet rotor,
In the low load operation region of the electric motor, the auxiliary coil is operated only by the magnetic flux of each permanent magnet piece of the permanent magnet group, and in the high load operation region, the auxiliary coil according to the rotor magnetic flux that is insufficient only by the magnetic flux of the permanent magnet piece. An electric motor characterized in that it is operated by energizing a necessary amount of current. 6. The electric motor according to claim 5 , wherein an amount of current to be supplied to the auxiliary coil is adjusted by a difference between a torque command value for the electric motor and a torque threshold value corresponding to the magnetic flux of the permanent magnet group. .

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