JP2012191758A - Rotary electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a higher harmonic wave induction type synchronous rotary electric machine which optimizes the number of slots of a stator and the number of magnetic poles of a rotor, and accordingly can obtain a larger torque.SOLUTION: A stator 3 and a rotor 2 are configured so as to satisfy 0.5≤(2s/3p)<1 where the number of slots 31b in a rotation direction of the rotor 2 is represented by a number of slots s, the number of magnetic poles formed on an excited protrusion part 21a in the rotation direction of the rotor 2 is represented by a number of poles p, and s is a multiple of 3 and p is an even number.

Description

  The present invention relates to a harmonic induction type synchronous rotating electric machine.

  There has been proposed a harmonic induction type rotating electrical machine including a rotor having magnetic poles that are induced by a harmonic component of a rotating magnetic field generated by a stator and excited and magnetized by an induced current flowing in a rotor winding. Japanese Patent Laying-Open No. 2009-112091 (Patent Document 1) discloses such a structure of a rotating electrical machine. According to this, the stator includes a stator core having a plurality of slots formed at intervals in the rotation direction (circumferential direction) of the rotor, and a plurality of stator windings wound around the stator through the slots. It is comprised. Here, the stator winding is a system in which windings wound around a plurality of teeth formed between the slots are concentrated around one tooth without overlapping each other in the rotation direction. Wrapped with concentrated winding (concentrated winding in a narrow sense). Similarly, the rotor is formed at intervals in the rotational direction (circumferential direction), and includes a plurality of protrusions arranged to face the stator, a rotor winding wound around the protrusions, and each rotor winding. And a rectifying element that rectifies a flowing current in one direction.

  With the above configuration, a rotating magnetic field having a harmonic component is excited by an alternating current flowing through the stator winding, and an induced electromotive force is generated in the rotor winding that is linked to the magnetic field of the harmonic component. Since the current flowing through the rotor winding by this induced electromotive force is rectified in one direction by the rectifying element, each protrusion is magnetized as a fixed-polarity electromagnet and becomes a magnetic pole. Thereby, the rotor becomes a field having a fixed magnetic pole, and torque that rotates in the rotating magnetic field is generated (Patent Document 1: Claim 1, paragraphs 22-36, etc.). However, in Patent Document 1, a configuration of a harmonic induction type rotating electrical machine is configured by replacing the configuration of the permanent magnet type rotating electrical machine almost as it is. That is, although a basic configuration of a harmonic induction type rotating electrical machine has been presented, it is understood that further improvement is necessary to obtain a larger torque.

JP 2009-112091 A

  In view of the above background, it is desired to realize a harmonic induction type synchronous rotating electric machine that can obtain a larger torque by optimizing the number of slots of the stator and the number of magnetic poles of the rotor.

In view of the above problems, the characteristic configuration of the rotating electrical machine according to the present invention is as follows:
Having a stator and a rotor arranged opposite to each other;
The stator has a stator core in which a plurality of slots are formed at intervals in the rotation direction of the rotor, and a three-phase stator winding wound around each tooth between the adjacent slots,
The stator winding is wound in a winding manner in which windings wound around different teeth and wound around different teeth are not overlapped in the rotation direction.
The rotor includes a rotor core in which a plurality of protrusions protruding toward the stator are formed at intervals in the rotation direction, rotor windings wound around the protrusions, and the rotor windings. A rectifying element that rectifies the current flowing in the line in a predetermined direction,
A magnetic pole having a polarity in which each protrusion is excited and fixed by an induced current that is induced in the rotor winding by a harmonic component of the armature magnetic flux from the stator winding and flows in one direction by the rectifying element. A rotating electric machine,
In the stator and the rotor, s is a multiple of 3 and p is an even number, where s is the number of slots that is the number of slots in the rotation direction, and p is the number of poles that is the number of magnetic poles in the rotation direction. And “0.5 ≦ (2s / 3p) <1”.

  In general, when the stator winding is wound around each tooth without overlapping the windings wound around different teeth in the rotation direction, the N-pole and S-pole of the rotor For two magnetic poles, three slots of the stator are provided corresponding to each of the three phases. Here, if the ratio “p: s” between the number of poles p, which is the number of magnetic poles, and the number of slots s, which is the number of slots, is “2: 3”, it is included in the armature magnetic flux from the stator winding. The harmonic component that becomes a noise component is reduced, and the loss of the rotating electrical machine is reduced. However, the rotating electric machine of this configuration is such that a magnetic pole is formed by an electromagnet by an induced current induced in the rotor winding by a harmonic component contained in the armature magnetic flux from the stator winding. Therefore, it is preferable that the armature magnetic flux from the stator winding includes a relatively large number of harmonic components, and the number of poles p and the number of slots s are also set so that the harmonic components of the armature magnetic flux increase. Is preferred.

  According to this feature configuration, the number of poles p and the number of slots s are set so as to satisfy the conditions of “s is a multiple of 3 and p is an even number” and “0.5 ≦ (2s / 3p) <1”. . When the ratio “p: s” between the number of poles p and the number of slots s is “2: 3”, “2s / 3p” is 1. When “p: s” is “2: 3n” (n is a natural number), “2s / 3p” is n. By setting “2s / 3p” so as not to be a natural number such as 1 or n, specifically, setting it to be a fraction, harmonic components included in the armature magnetic flux may increase. Confirmed by the inventors. Further, when n increases, even if the windings of the stator windings do not overlap in the rotation direction (concentrated winding), the characteristics of the overlapping windings (distributed winding) approach the characteristics of the armature magnetic flux. It is suppressed. Here, since it is preferable that the harmonic component of the armature magnetic flux is not suppressed, n is preferably 1. Therefore, in this feature configuration, “2s / 3p” is limited to less than 1 so that it does not become an improper fraction (a mixed number). When “2s / 3p” is less than 0.5, the rotor cannot be rotated in the rotating magnetic field. Therefore, in this feature configuration, “2s / 3p” is limited to 0.5 or more. In order to generate an armature magnetic flux (rotating magnetic field) by three-phase alternating current, a concentrated winding stator needs to be formed with slots (teeth) that are multiples of three. Further, since the same number of N poles and S poles is required for the magnetic poles of the rotor, the magnetic poles must be a multiple of 2, that is, an even number.

  As described above, according to this feature configuration, by devising the relationship between the number of poles p and the number of slots s, harmonic components contained in the armature magnetic flux can be increased even for rotating electrical machines of the same size. it can. As a result, the induced current induced in the rotor winding due to the harmonic component of the armature magnetic flux increases, and the magnetic flux (field magnetic flux) of the magnetic pole excited by the induced current also increases. Thereby, the torque generated by the armature magnetic flux and the field magnetic flux is also increased. In order to obtain a large torque, it is preferable that the field magnetic flux of the rotor is effectively linked to the stator winding. As an index indicating the effectiveness of the field magnetic flux interlinked with the stator winding, there is a winding coefficient indicating the effective utilization rate of the field magnetic flux in the stator by a value of 1 or less. The higher the winding coefficient, the more effectively the field magnetic flux is used in the stator, and the torque (magnet torque) generated by the armature magnetic flux and the field magnetic flux increases. The combination of the number of poles p and the number of slots s in which “2s / 3p” is 0.5 or more and less than 1 has a relatively high winding coefficient. Therefore, the torque generated by the armature magnetic flux and the field magnetic flux can be increased. As described above, according to this characteristic configuration, it is possible to obtain a harmonic induction type synchronous rotating electric machine that can obtain a larger torque by optimizing the number of slots of the stator and the number of magnetic poles of the rotor. .

  By the way, the rotor winding is formed at intervals in the rotation direction and wound around each of a plurality of protrusions protruding toward the stator. Further, the rotor is provided with a rectifying element that rectifies current flowing through each of the rotor windings in a predetermined direction. Most simply, at least one rectifying element is provided for each rotor winding at each protrusion. When one rectifying element is provided for each rotor winding in each protrusion, the total number of rectifying elements is the same as the number of protrusions, that is, the number of poles p that is the number of magnetic poles. However, the rotor windings in which the induced currents induced by the harmonic components of the armature magnetic flux have the same phase can also serve as a rectifying element. If the rectifying element can also be used, the total number of rectifying elements can be suppressed, the product cost can be suppressed, the rotor can be reduced in weight, and the efficiency of the rotating electrical machine can be improved. Whether or not the rectifying element can also be used depends on the relative position of the slot and the magnetic pole in the rotation direction. The mechanical variable range in the rotation direction of the stator and the rotor is 360 degrees. Therefore, the number of slots s and the number of poles p determine whether or not the rectifying element can be used, and the number of rectifying elements is also determined.

  As one preferable aspect, the number of the rectifying elements provided in the rotor is a value of “3m × (p / s)”, an expression represented by using the number of poles p, the number of slots s, and a natural number m. Can be the smallest even number. This number is the value of the numerator when the fraction p / s indicated using the number of poles p and the number of slots s is reduced so that the denominator is a multiple of 3 and the numerator is even and the numerator is the smallest. Is equivalent to In order to accommodate three-phase excitation by concentrated winding, the denominator needs to be a multiple of 3, and the magnetic poles of different polarities need to be rectified in different directions, so the numerator is a multiple of 2 (even) It is necessary to be. Even if a reduction is possible, if the reduction does not satisfy this condition, the relative positions of the magnetic poles of the same polarity (protrusions having the same polarity) and the slots (teeth) in the rotational direction of the rotor are Will be different. In this case, the phases of the induced currents induced in the rotor windings wound around the protrusions having the same polarity are also different. When the rotor windings are connected in series in this state and rectified using a common rectifying element, the induced current is offset by the difference in current phase, the total amount of induced current is reduced, and the magnetic flux for magnetizing the protrusion is also reduced. To do. In such a case, it is not appropriate to use a common rectifying element. From the above, when the above condition is satisfied and the fraction p / s can be reduced, the number of molecules can be made smaller than the number of poles p, and the rectifying element can be shared.

  As described above, the higher the winding coefficient indicating the effective utilization rate of the field magnetic flux in the stator with a value of 1 or less, the more effective the field magnetic flux is utilized in the stator, and the torque generated by the armature magnetic flux and the field magnetic flux. (Magnet torque) also increases. This winding coefficient is determined by the relationship between the stator winding wound around the teeth and the magnetic pole. In the present invention, the stator winding is a common winding in which windings wound around different teeth are concentrated around each tooth without overlapping in the rotation direction regardless of the number of slots. Wrapped in the direction. Therefore, it is preferable that the number of slots and the number of poles are set on the condition of the winding coefficient. In one aspect, the stator and the rotor are configured such that a winding coefficient indicating an effective utilization rate of the field magnetic flux provided from the rotor in the stator by a value of 1 or less is greater than 0.9. It is preferable that the number of slots and the number of poles are set.

Axial sectional view schematically showing an example of a harmonic induction type synchronous rotating electric machine Cross-sectional view perpendicular to axis schematically showing an example of a harmonic induction type synchronous rotating electrical machine The figure which shows typically an example of the rectification | straightening direction by the connection of a rotor winding | winding, and a rectifier The figure which shows typically other examples of the rectification | straightening direction by the connection of a rotor winding | winding, and a rectifier Comparative diagram schematically showing the relationship between the structure of the rotating electrical machine and the harmonic components of the armature magnetic flux The graph which shows an example of the torque-rotation speed characteristic for every structure of a rotary electric machine The figure which shows the electrical angle of the stator of the slot number 12 which opposes the rotor of the pole number 8 The figure which shows the electrical angle of the stator of the number of slots 9 facing the rotor of the number of poles 8 The figure which shows the electrical angle of the stator of the number of slots 6 facing the rotor of the number of poles 8 The figure which shows the electrical angle of the stator of the slot number 12 which opposes the rotor of the pole number 10 The figure which shows the electrical angle of the stator of the slot number 15 which opposes the rotor of the pole number 14

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the rotating electrical machine of the present embodiment, an induced current is induced in the rotor winding wound around the protrusion formed on the rotor core by the harmonic component of the armature magnetic flux from the stator winding, and the protrusion is generated by this induced current. Is a harmonic induction type synchronous rotating electrical machine that is excited to become a magnetic pole. First, the basic structure of a harmonic induction type synchronous rotating electrical machine will be described. As shown in FIG. 1, the rotating electrical machine 1 includes a rotor 2 and a stator 3 that are arranged to face each other, and is housed in a case (not shown). The rotating electrical machine 1 functions as a motor (electric motor) that obtains power (rotational driving force) of the rotor 2 by electric power supplied to the stator 3 and generates power in the stator 3 by power of the rotor 2 (generator). Also works. Each drawing referred to in the following description schematically shows a configuration necessary for understanding the present invention. A part of the configuration such as a fastening member such as a bolt for attaching the member and a mounting hole through which the fastening member passes is appropriately omitted.

  As shown in FIGS. 1 and 2, the rotating electrical machine 1 is an inner rotor type rotating electrical machine in which a rotor 2 is disposed on the radially inner side of a stator 3. The stator 3 is fastened and fixed to the inner surface of a case (not shown) using, for example, bolts. The stator 3 includes a stator core 31 and a three-phase stator winding 32 wound around the stator core 31 and constitutes an armature of the rotating electrical machine 1. In the present embodiment, the stator core 31 is configured by laminating a plurality of electromagnetic steel plates in the direction of the rotation axis of the rotor 2, and is formed in a cylindrical shape as a whole as shown in FIG. On the inner peripheral surface side of the stator core 31, that is, on the side facing the rotor 2, a plurality of teeth 31 a are formed at regular intervals in the circumferential direction (rotating direction of the rotor 2). Thereby, the slot 31b is formed at intervals between the teeth 31a adjacent in the circumferential direction. A stator winding 32 for generating an armature magnetic flux serving as a rotating magnetic field is wound around each tooth 31a so as to be accommodated in the slot 31b. In the example illustrated in FIG. 2, the number of slots that is the number of slots 31 b (the number of teeth that is the number of teeth 31 a) is twelve.

  In the stator winding 32, the windings of each phase are intensively wound around each tooth 31a so that the windings of each of the three phases (U, V, W phase) do not overlap each other in the circumferential direction. It is wound by a winding method (concentrated winding in a narrow sense. Hereinafter, abbreviated as “concentrated winding” where appropriate). Further, in a winding method (non-full-pitch winding) that is not full-pitch winding in which the interval (magnetic pole pitch) of the magnetic poles of the rotor 2 described later is the same as the interval (winding pitch) in which the stator windings 32 are wound. It is wound. In the example shown in FIG. 2, the stator winding 32 for the U phase, the stator winding 32 for the V phase, and the stator winding 32 for the W phase are sequentially counterclockwise in the drawing along the circumferential direction. Arranged to appear. In the example shown in FIG. 2, the number of slots (the number of teeth) is 12. That is, the stator winding 32 is wound so that three-phase excitation corresponding to four electrical angles can be performed in one mechanical revolution of the stator 3. In the present specification and drawings, in order to distinguish the difference in the direction of the current flowing through the stator winding 32 (current phase), the names of the respective phases are appropriately labeled with “+” and “−”. , U +, V +, W +, U−, V−, W− phases.

  The rotor 2 is disposed on the radially inner side of the stator 3 so as to be rotatable relative to the stator 3. The rotor 2 includes a rotor core 21 and a rotor winding 22 wound around the rotor core 21 to constitute a field of the rotating electrical machine 1. As with the stator core 31, the rotor core 21 is formed by laminating a plurality of electromagnetic steel plates in the rotation axis direction, and is formed in a cylindrical shape as a whole. As shown in FIGS. 2 and 3, the rotor core 21 is formed with an insertion hole 23 for inserting a rotor shaft 41 serving as a rotation shaft. The rotor shaft 41 is fixed to the rotor core 21 while being inserted into the insertion hole 23 by, for example, press fitting, shrink fitting, or key coupling, and rotates integrally with the rotor core 21. The rotor shaft 41 is rotatably supported by a case (not shown) at both ends in the axial direction.

  The rotor core 21 includes a plurality of protrusions 21a that protrude toward the stator 3 and that are formed at regular intervals in the rotation direction. In the present embodiment, the circumferential width of the protrusion 21a is set to a width smaller than a width corresponding to 180 degrees in electrical angle with respect to the magnetic pole of the rotor 2 described later, for example, about 90 degrees. . The protrusion 21a is formed by the end surface of the protrusion 21a on the radially outer side (side facing the stator 3) and the teeth 31a formed on the stator core 31 in a state where the rotor 2 and the stator 3 are attached to a case (not shown). It is provided such that a minute radial interval is formed between the end surface on the radially inner side (the side opposite to the rotor 2). A rotor slot 21b is formed at an interval between the protrusions 21a adjacent in the circumferential direction. Around each protrusion 21a, a rotor winding 22 for winding an induced current induced by a harmonic component of the armature magnetic flux is wound so as to be accommodated in the rotor slot 21b. That is, the rotor winding 22 is wound through a pair of rotor slots 21b that are adjacent in the circumferential direction across the protrusion 21a. As will be described later, due to the current (inductive current) flowing through the rotor winding 22, each protrusion 21 a becomes an electromagnet and becomes a magnetic pole of the rotor 2. In the example illustrated in FIG. 2, the number of poles (the number of protrusions 21 a) that is the number of magnetic poles is eight.

  In the same manner as the stator winding 32, the rotor winding 22 is configured such that windings are wound around the protrusions 21a intensively around the protrusions 21a and the windings wound around the different protrusions 21a are rotated. It is wound in a winding method that does not overlap in the direction (concentrated winding in a narrow sense). That is, the rotor windings 22 wound around each protrusion 21a are intensively wound around one protrusion 21a so as not to overlap each other in the circumferential direction. In the present embodiment, as shown in FIG. 2, a protruding portion that protrudes along the circumferential direction is formed from the protruding portion 21 a toward the rotor slot 21 b at the radially outer end of the protruding portion 21 a. ing. And the plate-shaped member 24 which consists of a nonmagnetic material is arrange | positioned so that it may be hold | maintained at this protrusion part. As a result, even when the rotor 2 in which centrifugal force is generated is rotated, the rotor winding 22 is appropriately held so as not to come out radially outward.

  As shown in FIGS. 1 to 3, a diode (rectifier element) 100 is connected to the rotor winding 22 via a connection conductor 101 such as a conductive wire covered with an insulating film. The diode 100 regulates the current flowing through the rotor winding 22 in a predetermined direction. In the present embodiment, the diode 100 is disposed and fixed in the recess 50 provided in the inner peripheral portion including the inner peripheral surface of the rotor core 21. Thereby, it is possible to arrange the diode 100 while suppressing a decrease in the rotational balance of the rotor 2 and to ensure the strength of the rotor 2 appropriately. At this time, it is preferable to dispose the diode 100 at a position where the influence on the magnetic flux passing through the rotor core 21 is small.

  Here, the rectification of the rotor winding 22 and the magnetization of the protrusion 21a due to the induced current flowing through the rotor winding 22 will be described. As shown in FIG. 3, the rotor windings 22 wound around the protrusions 21a adjacent in the circumferential direction are rectified by the diode 100 so as to allow the induction currents to flow in opposite directions. The rotor winding 22 includes a first rotor winding 22a (solid line) through which the induced current flows in the first direction and a second rotor winding through which the induced current flows in the second direction opposite to the first direction. 22b (broken line). As shown in FIG. 3, the first rotor winding 22 a and the second rotor winding 22 b are alternately wound around the protrusions 21 a along the rotation direction of the rotor 2. Since the induced current flowing through the first rotor winding 22a and the second rotor winding 22b is regulated in one direction by the diode 100, the adjacent protrusions 21a become electromagnets fixed to different polarities. Specifically, an S pole is formed on the radially outer side (stator 3 side) of the protrusion 21a around which the first rotor winding 22a is wound, and the protrusion 21a around which the second rotor winding 22b is wound is formed. An N pole is formed on the radially outer side. That is, each protrusion 21a is magnetized so that the N pole and the S pole are alternately arranged in the rotation direction of the rotor 2 to form a magnetic pole. Since the number of the protrusions 21a is 8, the number of poles which is the number of magnetic poles is 8.

  Although details will be described later, the phase of the armature magnetic flux interlinked by the two or more first rotor windings 22a is always the same regardless of the rotation angle of the rotor 2, and the two or more second rotor windings. In some cases, the phase of the armature magnetic flux that 22b is linked to is always the same. In this case, the phases of the induced currents generated in the two or more first rotor windings 22a are the same, and the phases of the induced currents generated in the two or more second rotor windings 22b are also the same. Therefore, these first rotor windings 22a can be rectified in a lump, and these second rotor windings 22b can also be rectified in a lump.

  Specifically, the first rotor windings 22a and the second rotor windings 22b are connected in series, and one diode 100 is connected to the series-connected circuit, whereby two or more rotor windings are connected. It is possible to rectify the line 22 with a single diode 100. That is, by using the diode 100 also, it is possible to reduce the number of diodes 100 installed in the rotor 2. The rotating electrical machine 1 illustrated in FIGS. 1 to 3 can also use the diode 100, and FIG. In the form shown in FIG. 4, the first rotor windings 22a for four lines are connected in series, one diode 100 is provided in this series circuit, and the second rotor windings 22b for four lines are connected in series. One diode 100 is provided in the series circuit. In the form shown in FIG. 4, in view of the increase in the current capacity by adding the induced currents flowing through the plurality of rotor windings 22, the recess 50 is enlarged and 2 so that the current capacity of the diode 100 can be increased. The case where it is set as a location is illustrated.

  By the way, the protrusion 21a is formed on the rotor core 21, so that the magnetic resistance when the armature magnetic flux from the stator 3 passes through the rotor core 21 changes depending on the position in the circumferential direction. Specifically, the magnetic resistance is low at the position where the protrusion 21a is disposed in the circumferential direction, and the magnetic resistance is increased due to the air gap at the position where the rotor slot 21b is disposed in the circumferential direction. When a three-phase alternating current is supplied to the stator winding 32 to generate a rotating magnetic field (armature magnetic flux) in the stator 3, the protrusion 21 a becomes a rotating magnetic field so that the magnetic resistance of the magnetic flux passing through the rotor core 21 is reduced. Sucked. That is, the rotor 2 rotates in synchronization with the rotating magnetic field formed by the stator 3, more precisely, the fundamental wave component of the rotating magnetic field. That is, reluctance torque is generated in the rotor 2 and the rotor 2 is rotationally driven.

  The rotor 2 is configured to generate a torque corresponding to the magnet torque in addition to the reluctance torque. As described above, the protrusion 21 a of the rotor 2 becomes an electromagnet having a fixed polarity due to the harmonic component contained in the armature magnetic flux from the stator winding 32. The attractive force and repulsive force between the field magnetic flux from the electromagnet and the rotating magnetic field (armature magnetic flux) from the stator winding 32 become the magnet torque. Specifically, when a three-phase alternating current is supplied to the stator winding 32 to generate a rotating magnetic field (armature magnetic flux), an induced current is generated in the rotor winding 22 due to harmonic components contained in the armature magnetic flux. As a result, each protrusion 21a becomes a fixed magnetic pole. Then, an attractive force and a repulsive force are generated between the protrusion 21 a (magnetic pole) and the rotating magnetic field, and the rotor 2 rotates in synchronization with the fundamental wave component of the rotating magnetic field formed by the stator 3. Thus, the rotating electrical machine 1 can rotate the rotor 2 by using both the magnet torque and the reluctance torque.

  Here, if the protrusion 21a is a strong electromagnet, it is effective in increasing the magnet torque. In order to make the protrusion 21a a strong electromagnet, the induced current flowing in the rotor winding 22 wound around the protrusion 21a may be increased. Since the induced current is induced by a harmonic component contained in the armature magnetic flux from the stator winding 32, the protrusion 21a can be made a strong electromagnet by increasing the harmonic component. In general, it is not preferable that a harmonic component is included in the armature magnetic flux such as a permanent magnet type rotating electric machine because it increases losses such as iron loss and copper loss. Therefore, the stator winding 32 is wound with distributed winding wound around a plurality of teeth 31a, not concentrated winding around the teeth 31a so as to suppress harmonic components. There are many cases. However, as illustrated with reference to FIGS. 1 to 3 and the like, the harmonic induction rotating electrical machine 1 uses the harmonic component positively to magnetize the protrusion 21a of the rotor 2 in order to magnetize the protrusion 21a. The wire 32 is wound by concentrated winding. Furthermore, it is possible to increase the harmonic component of the armature magnetic flux from the basic structure illustrated in FIGS. 1 to 3, which will be described below.

  Specifically, the harmonic component of the armature magnetic flux is further increased by appropriately setting the relationship between the number of slots 31b of the stator 3 and the number of poles that is the number of magnetic poles of the rotor 2. It is possible. Hereinafter, a description will be given with reference to FIGS. First, s is the number of slots 31 b in the rotation direction of the rotor 2, p is the number of magnetic poles in the rotation direction of the rotor 2, 1 pole pair of magnetic poles in the concentrated winding and 1 of the AC rotating magnetic field. The number of windings per phase is defined as q (hereinafter referred to as “the number of windings q per pole pair per phase” as appropriate). The number of windings q per pole pair / phase is represented by “2s / 3p”. In the case of the rotating electrical machine 1 having the basic structure illustrated in FIGS. 1 to 3, since the number of slots s = 12 and the number of poles p = 8, q is “1”. That is, the number of windings q per pole pair / phase is an integer (natural number).

  FIG. 5 compares the harmonic components of the armature magnetic flux of three types of rotating electrical machines 1 having different structures. FIG. 5A shows the basic structure illustrated in FIGS. 1 to 3, and is a rotating electrical machine 1 having a slot number s = 12 and a pole number p = 8. As described above, q is an integer of “1”. FIG. 5B shows the rotating electrical machine 1 having the number of slots s = 9 and the number of poles p = 8, and q is a fraction of “3/4”. FIG. 5C shows the rotating electrical machine 1 having the number of slots s = 6 and the number of poles p = 8, and q is a fraction of “½”. That is, FIGS. 5A to 5C exemplify rotating electrical machines 1 having the same structure in which the number of poles p is all eight but different in the number of slots s. The bar graph of FIG. 5 shows the order (horizontal axis) of the harmonic component of the armature magnetic flux interlinking with the rotor winding 22 and the amplitude (vertical axis) of the magnetic flux.

  As shown in this bar graph, in the rotating electrical machine 1 having a structure in which the number of windings q per pole pair per phase is a fraction, the harmonic component of the armature magnetic flux increases compared to the rotating electrical machine 1 where q is an integer. Yes. Specifically, as shown in FIGS. 5A and 5B, the 2.25th harmonic component, which is the maximum harmonic component in the rotating electrical machine 1 with q = 3/4, is the rotation of q = 1. The amplitude is about five times the sixth harmonic component, which is the maximum harmonic component in the electric machine 1. Further, as shown in FIGS. 5A and 5C, the 1.50th harmonic component that is the maximum harmonic component in the rotating electrical machine 1 with q = 1/2 is the same as that in the rotating electrical machine 1 with q = 1. The amplitude is about 6 times the 6th harmonic component, which is the largest harmonic component.

  FIG. 6 is a graph showing an example of torque-rotational speed characteristics obtained by simulation for each structure of the rotating electrical machine 1. In FIG. 6, (m) is a target torque, and (d) is a torque characteristic of an embedded magnet type synchronous rotating electrical machine (IPMSM) in which a stator winding is wound by distributed winding. (N) is a torque when only the reluctance torque is generated without winding the rotor winding 22 around the rotor 2 in the rotating electrical machine 1 having the basic structure shown in FIGS. 1 to 3 and 5A. It is a characteristic. (A) is a torque characteristic of the rotary electric machine 1 of the basic structure shown to FIGS. 1-3 and FIG. 5 (a), and is a torque characteristic of the synthetic torque of both a reluctance torque and a magnet torque. FIG. 5B is a torque characteristic of the rotating electrical machine 1 having the structure shown in FIG. 5B, and similarly is a torque characteristic of a combined torque of the reluctance torque and the magnet torque.

  As shown in FIG. 6, the torque characteristic (a) of the rotating electrical machine 1 in which the number of windings q per pole pair / phase is an integer is observed as a magnet torque superimposed on the reluctance torque (n) in a low rotation range. However, there is almost no difference from the reluctance torque (n) above the middle rotation range. That is, the torque characteristic (a) of the rotating electrical machine 1 having the basic structure is not large enough to reach the target torque (m). On the other hand, the torque characteristic (b) of the rotating electrical machine 1 in which the number of windings q per pole pair / phase is a fraction is greatly improved, and particularly in the middle rotation range, the target torque (m) and the torque of the IPMSM. It exceeds the characteristic (d). In this way, by making the number of windings q per pole pair per phase not a whole number (natural number) but a fraction, the harmonic component of the armature magnetic flux is increased and the field magnetic flux of the rotor 2 is increased. It is possible to increase the output torque.

  Here, when the number of windings q per pole pair per phase is a fraction, it can also include an improper fraction (a mixed number), but when q exceeds 1, it approaches a distributed winding, It does not contribute to the increase of harmonic components. Therefore, in order to increase the harmonic component, it is preferable that the number of slots s and the number of poles p are set so that the number of windings q per pole pair per phase becomes a proper fraction. If q is less than 1/2 (= 0.5), the attractive force and repulsive force of the magnetic pole pair cannot be applied to the rotating magnetic field, and the rotor 2 cannot be rotated. Therefore, it is necessary to set the number of slots s and the number of poles p so that the number of windings q per pole pair / phase becomes 1/2 or more. In summary, when the harmonic induction type synchronous rotating electrical machine 1 capable of increasing the harmonic component of the armature magnetic flux and obtaining a larger magnet torque is satisfied, the following formula (1) is satisfied. Thus, the number of slots s and the number of poles p should be optimized. Of course, the number of poles p is an even number because it is twice the number of pole pairs, and the number of slots s is a multiple of 3 because the three-phase stator winding 32 is wound by concentrated winding.

0.5 ≦ q <1,
0.5 ≦ (2s / 3p) <1 (1)

  By the way, when the number of pole pairs is 4, the stator winding 32 is wound so that a rotating magnetic field (armature magnetic flux) corresponding to four cycles in electrical angle is generated in one mechanical rotation of the stator 3. It is necessary to When the stator winding 32 is wound by non-total joint winding and concentrated winding, for example, twelve teeth 31a (slots 31b) are provided as shown in FIG. That is, as shown in FIG. 7, twelve stator windings 32 are wound so that the phase difference in electrical angle between adjacent phases in the circumferential direction is 120 degrees. As a result, the rotation of the stator 3 becomes 1440 degrees (= 360 × 4), and a rotating magnetic field corresponding to four cycles can be generated in three phases. However, the number of slots s of the stator 3 illustrated in FIGS. 5B and 5C is less than 12. Therefore, in order to generate a rotating magnetic field (armature magnetic flux) for three phases and four cycles with a small number of slots s, the winding method of the stator winding 32 and the arrangement in the circumferential direction are devised.

  FIG. 8 shows the winding form of the stator winding 32 of the rotating electrical machine 1 having the structure of q = 3/4 shown in FIG. 5B and the electrical angle. As shown in FIG. 8, the U + phase and the U− phase, the V + phase and the V− phase, and the W + phase and the W− phase are wound around the adjacent teeth 31a. That is, the stator winding 32 is wound so that the current flow direction is opposite. Normally, when the U phase and the V phase are adjacent, the electrical angle between them is 120 degrees, but when the U + phase and the U− phase are adjacent, the electrical angle between them is 180 degrees. It becomes. Therefore, as shown in FIG. 8, when the U + phase, the U− phase, the U + phase, the V + phase, the V− phase, the V + phase, the W + phase, the W− phase, and the W + phase are arranged counterclockwise. The electrical angle between the phases is repeated as 180 degrees, 180 degrees, 120 degrees, etc., and when the stator 3 is mechanically rotated once, it becomes 1440 degrees (= 360 × 4). Since this corresponds to four periods in terms of electrical angle, a rotating magnetic field (armature magnetic flux) corresponding to four periods in terms of electrical angle can be generated in one mechanical revolution of the stator 3.

  FIG. 9 shows the winding form of the stator winding 32 and the electrical angle of the rotating electrical machine 1 having the structure of q = 1/2 shown in FIG. In this case, the stator windings 32 of each phase are wound by skipping one phase at a time, rather than being arranged counterclockwise with the U phase, V phase, and W phase. That is, the electrical angle between adjacent phases is such that the V phase is skipped after the U phase, the W phase is skipped, the U phase is skipped after the W phase, the V phase is skipped, and the W phase is skipped after the V phase. The stator winding 32 of each phase is wound so that the angle becomes 240 degrees. As a result, when the stator 3 is rotated once, it becomes 1440 degrees (= 360 × 4). Accordingly, it is possible to generate a rotating magnetic field (armature magnetic flux) corresponding to four cycles in terms of electrical angle in one turn of the stator 3.

  As described above, the number of slots s and the number of poles p are appropriately set so that the number of windings q per pole pair per phase is a fraction of 0.5 or more and less than 1, and the harmonic component of the armature magnetic flux is set. It is possible to appropriately set the electrical angle in the stator 3 while ensuring the above. In the above description with reference to FIG. 5 and the like, the case where all the number of poles p of the rotor 2 is 8 is exemplified, but naturally the number of poles p may take other values. Table 1 below shows an example of the relationship between the combination of the number of slots s and the number of poles p and the number of windings q per pole pair per phase. The combinations in which the number of slots s and the number of poles p match and the stator winding 32 is a full-pitch winding are excluded. In Table 1, the value of q in the combination where q is a fraction of 0.5 or more and less than 1 is described. However, since it is a boundary value, the combination where q = 1 is also indicated in parentheses. ing.

  10 and 11 show an example of the rotating electrical machine 1 in which the number of poles p of the rotor 2 is other than eight. The rotating electrical machine 1 shown in FIG. 10 has pole number p = 10 and slot number s = 12. In the case of this structure, as shown in Table 1, the number of windings q per pole pair / phase is 4/5 (= 0.80). Since the rotor 2 of the rotating electrical machine 1 has a pole pair number of 5 (= 10/2), a rotating magnetic field (armature magnetic flux) corresponding to five electrical angles is generated in one mechanical revolution of the stator 3. The stator winding 32 is wound so as to be able to. That is, as shown in FIG. 10, the stator windings 32 are arranged in the counterclockwise direction so as to be U + phase, U− phase, V− phase, V + phase, W + phase, W− phase, U− phase,. Is wound. The electrical angle between the phases is repeated counterclockwise as 180 degrees, 120 degrees, 180 degrees, 120 degrees, and so on. That is, when the stator 3 makes one turn, the electrical angle becomes 1800 degrees (= 360 × 5), and the stator winding 32 is wound so that a rotating magnetic field (armature magnetic flux) corresponding to five cycles can be generated by the electrical angle. Is done. Note that a winding coefficient Kw described later is 0.93.

  The rotating electrical machine 1 shown in FIG. 11 has pole number p = 14 and slot number s = 15. In the case of this structure, as shown in Table 1, the number q of windings per pole pair per phase is 5/7 (= 0.71). Since the rotor 2 of the rotating electrical machine 1 has a pole pair number of 7 (= 14/2), a rotating magnetic field (armature magnetic flux) corresponding to 7 cycles in electrical angle is generated in one mechanical revolution of the stator 3. The stator winding 32 is wound so as to be able to. That is, as shown in FIG. 11, the stator windings are arranged in a counterclockwise direction such as U + phase, U− phase, U + phase, U− phase, U + phase, V + phase, V− phase, V + phase,. A wire 32 is wound. The electrical angle between the phases is repeated counterclockwise as 180 degrees, 180 degrees, 180 degrees, 180 degrees, 120 degrees, 180 degrees, and so on. That is, when the stator 3 makes one turn, the electrical angle becomes 2520 degrees (= 360 × 7), and the stator winding 32 is wound so that a rotating magnetic field (armature magnetic flux) corresponding to seven cycles can be generated by the electrical angle. Is done. Note that a winding coefficient Kw described later is 0.95.

  By the way, in order to obtain a large magnet torque, it is preferable that the field magnetic flux from the rotor 2 is efficiently linked to the stator winding 32. As an index indicating the effectiveness of the field magnetic flux interlinked with the stator winding 32, there is a winding coefficient Kw indicating the effective utilization rate of the field magnetic flux in the stator by a value of 1 or less. The higher the winding coefficient Kw, the more effective the field magnetic flux is linked to the stator winding 32, and the larger the magnet torque generated by the rotating magnetic field (armature magnetic flux) and the field magnetic flux. The winding coefficient Kw is determined by the relationship between the stator winding 32 wound around the tooth 31a and the magnetic pole. Preferably, the number of slots s and the number of poles p are set so that a winding coefficient Kw indicating an effective utilization rate of the field magnetic flux provided from the rotor 2 in the stator 3 by a value of 1 or less is larger than 0.9. It should be set. Table 2 below shows the winding coefficient Kw corresponding to the combination of the number of slots s and the number of poles p in which the number of windings q per pole pair per phase is a fraction of 0.5 or more and less than 1 in Table 1 above. Yes. In Table 2, winding coefficient Kw larger than 0.9 is shown in bold. In Table 2, as a reference value, the winding coefficient Kw for the combination where q = 1 is also shown in parentheses.

  Although the description in Table 2 is omitted, in the case of a combination of the number of slots s and the number of poles p in which the number of windings q per pole pair per phase is 1 or more, the winding coefficient Kw is approximately It becomes a value smaller than 0.8. That is, in the case of a combination of the number of slots s and the number of poles p where the number of windings q per pole pair per phase is 0.5 or more and less than 1, the winding coefficient Kw can be set to a relatively high value. . As a result, the magnet torque generated by the armature magnetic flux and the field magnetic flux can be increased.

  From the above description with reference to Table 1 and Table 2, the combination of the number of slots s and the number of poles p satisfying “0.5 ≦ q <1” and satisfying “Kw> 0.9” gives a larger torque. It turns out that it is very suitable in the structure of the rotary electric machine 1 for obtaining. This is summarized in Table 3 below. In Table 3, one column (*) indicated by * is a combination that satisfies only the condition of the number of windings q per pole pair per phase. Two columns marked with * (**) indicate a combination that satisfies both the number of windings q per pole pair per phase and a winding coefficient Kw, and is an optimal combination.

  Here, it supplements about the winding coefficient Kw. The winding coefficient Kw is represented by the product of the short-pitch winding coefficient Ks and the distributed winding coefficient Kd (Kw = Ks · Kd). First, the short winding coefficient Ks will be described. When the interval at which the stator winding 32 is wound in the stator 3 (winding pitch) and the interval between the magnetic poles in the rotor 2 (magnetic pole pitch) are the same, it is referred to as “full-pitch winding”. In the case of full-pitch winding, the phase difference between the voltages generated in the two adjacent stator windings 32 by the rotation of the rotor 2 is 180 degrees. On the other hand, when the number of slots s is 9 and the number of poles p is 8, the winding pitch is smaller than the magnetic pole pitch. Further, when the number of slots s is 6 and the number of poles p is 8, the winding pitch is larger than the magnetic pole pitch. These are referred to herein as “non-full-pitch winding”. In particular, when the winding pitch is smaller than the magnetic pole pitch, it is called “short-pitch winding”. In the case of non-full-pitch winding, the phase difference between the voltages generated in the two adjacent stator windings 32 due to the rotation of the rotor 2 is shifted from 180 degrees.

  In the case of non-full-pitch winding, the above-described phase difference occurs in the voltage induced in the stator winding 32 by the field magnetic flux. For this reason, the voltages generated in the adjacent stator windings 32 are vectors having different directions, and the generated voltage is a vector sum of the respective voltages. On the other hand, in the case of full-pitch winding, the algebraic sum of the respective voltages is sufficient because the vectors have the same direction. For this reason, the generated voltage for the same field magnetic flux is smaller in the non-full-pitch winding than in the full-pitch winding. The ratio of the induced electromotive force in the non-full-pitch winding to the induced electromotive force in the full-pitch winding is given as a coefficient. In general, since most of the non-whole-pitch winding is short-pitch winding, this coefficient is referred to as a short-pitch winding coefficient Ks. In other words, the short-pitch winding coefficient Ks is a coefficient indicating the ratio of the induced electromotive force in the short-pitch winding to the induced electromotive force in the full-pitch winding as described below.

Ks = short-pitch induced electromotive force / full-pitch induced electromotive force = vector sum of induced electromotive forces / algebraic sum of induced electromotive forces

  The winding pitch is the same as the pitch of the teeth 31a (slots 31b) in the case of concentrated winding. Therefore, the winding pitch can be expressed using the number of slots s. Here, when the winding pitch is Ws (= 2π / s) and the magnetic pole pitch in the rotor 2 is Wp (= 2π / p), the short-pitch winding coefficient Ks is expressed by the following formula (2).

  Table 4 below shows the short-pitch winding coefficient Ks for a combination of the number of slots s and the number of poles p that satisfies “0.5 ≦ q <1” in Table 1 above. As a reference value, the short-pitch coefficient Ks for the combination where q = 1 is also shown in parentheses.

  A person skilled in the art can easily obtain the value from the above equation (2), so the description in Table 4 is omitted, but the number of windings q per pole pair per phase is 1. In the case of the combination of the number of slots s and the number of poles p as described above, the short winding coefficient Ks is a value smaller than about 0.85. As a result, the value of the winding coefficient Kw indicated by the product of the short-pitch winding coefficient Ks and the distributed winding coefficient Kd is generally smaller than 0.8 as described above.

  Next, the distributed winding coefficient Kd will be described. A winding method in which the number of teeth 31a (number of slots s) around which the stator winding 32 is wound is one for each phase is referred to as concentrated winding. That is, the stator winding 32 is intensively wound around each tooth 31a, and the windings wound around different teeth 31a do not overlap in the rotation direction. On the other hand, for each phase, a winding method in which the number of teeth 31a (number of slots s) around which the stator winding 32 is wound is two or more is called distributed winding. In the case of distributed winding, the windings wound around different teeth 31a overlap in the rotation direction. In the case of distributed winding, it is known that the waveform of the voltage induced in the stator winding 32 by the rotation of the rotor 2 is rounded and harmonic components are suppressed. However, the induced electromotive force is reduced as compared with the concentrated winding. As shown below, the distributed winding coefficient Kd is a coefficient indicating the ratio of the induced electromotive force in the distributed winding to the induced electromotive force in the concentrated winding.

  Kd = distributed winding induced electromotive force / concentrated winding induced electromotive force

As described above, distributed winding and concentrated winding differ in the number of slots s per phase in the stator 3. Accordingly, the distributed winding coefficient Kd can be expressed by the following equation (3) using the “number of windings q ₂ ” obtained from the number of pole pairs (or the number of poles p) of the rotor 2 and the number of slots s. . “Number of windings q ₂ per unit” is a value obtained by multiplying the number of windings q per one pole pair per phase by a natural number c, that is, a minimum integer (natural number), that is, “q ₂ = c · q "Is the smallest integer (natural number). When q is an integer (natural number), “q ₂ = q”, and when q is a fraction, q ₂ is a numerator of q. In the case of distributed winding, q is “the number of windings per pole per phase: s / 3p”, and the value is limited to an integer.

  Table 4 below shows the distributed winding coefficient Kd for the combination of the number of slots s and the number of poles p satisfying “0.5 ≦ q <1” in Table 1 above. As a reference value, the distributed winding coefficient Kd for the combination where q = 1 is also shown in parentheses.

  The winding coefficient Kw is represented by the product of the short-pitch winding coefficient Ks and the distributed winding coefficient Kd obtained in this way (Kw = Ks · Kd).

  Next, the rectifying element (diode 100) arranged in the rotor winding 22 in order to magnetize each protrusion 21a as a fixed polarity electromagnet will be described. In order to magnetize each protrusion 21a independently to a fixed polarity, it is necessary to connect the diode 100 to the rotor winding 22 wound around each protrusion 21a as illustrated in FIG. is there. In this case, the total number of diodes 100 is the same as the number of protrusions 21a, that is, the number of poles p that is the number of magnetic poles. However, as described with reference to FIG. 4, the diodes 100 of the plurality of rotor windings 22 can also be used. Specifically, regardless of the rotation angle of the rotor 2, the rotor winding 22 in which the induced currents induced by the harmonic components of the armature magnetic flux have the same phase can also serve as a rectifying element. Whether or not the diode 100 can be used in combination is determined by the relative relationship between the tooth 31a (slot 31b) and the magnetic pole (projection 21a). Since the teeth 31a and the magnetic poles are arranged at equal intervals, whether or not they can be combined is determined by the relationship between the number of teeth 31a (number of slots s) and the number of magnetic poles (number of poles p). That is, the required number of diodes 100 (number of elements nd) can be defined.

  Specifically, the number of elements nd can be set to an expression represented by using the number of poles p, the number of slots s, and the natural number m, and the number “3m × (p / s)” is the smallest even number. . This number is obtained by dividing the fraction p / s indicated by using the number of poles p and the number of slots s so that the denominator is a multiple of 3 and the numerator is an even number so that the numerator is the smallest. It is equivalent to the value. In order to accommodate three-phase excitation by concentrated winding, the denominator needs to be a multiple of 3, and the magnetic poles of different polarities need to be rectified in different directions, so the numerator is a multiple of 2 (even) It is necessary to be.

  Even if the reduction is possible, if the reduction does not satisfy this condition, the rotation direction of the rotor 2 between the magnetic pole having the same polarity (the projection 21a having the same polarity) and the slot 31b (the teeth 31a) The relative positions at are different. In this case, the phases of the induced currents induced in the rotor windings 22 wound around the protrusions 21a having the same polarity are also different. When the rotor windings 22 are connected in series in this state and rectified by using the common diode 100, the induced current is canceled by the difference in the current phase, the total amount of the induced current is reduced, and the magnetic flux for magnetizing the protrusion 21a. Also decreases. In such a case, it is not appropriate to use the diode 100 in common. As described above, when the above condition is satisfied and the fraction p / s can be reduced, the number of molecules can be made smaller than the number of poles p, and the diode 100 can be shared.

  Therefore, it is preferable that the number of the diodes 100 is set so as to satisfy the above condition. Since the number of diodes 100 defined by this condition is the minimum value, even if they can be used together, the diodes 100 are provided for each rotor winding 22 wound around each protrusion 21a without using them. May be connected. Table 6 below shows the number of elements nd for the combination of the number of slots s and the number of poles p satisfying “0.5 ≦ q <1” in Table 1 above. Further, a symbol “*” is attached to a combination of the number of slots s and the number of poles p that satisfies “Kw> 0.9”. As a reference value, the element number nd for the combination where q = 1 is also shown in parentheses.

  Referring to Table 6, “0.5 ≦ q <1” and “Kw> 0.9” are satisfied, which is a structure of the rotating electrical machine 1 that is very suitable for obtaining a larger torque. In the combination of the number of slots s and the number of poles p, it is often necessary to individually connect the diode 100 to each rotor winding 22. That is, the number of poles p and the number of elements nd are often the same value. However, in part, even in such an optimal structure, there are combinations that can suppress the diode 100. By adopting such a combination, it is possible to obtain the rotating electrical machine 1 with a larger torque and a reduced manufacturing cost.

  As described above, according to the present invention, the number of slots s of the stator 3 around which the stator winding 32 is wound by non-all-nodes / concentrated winding and the harmonic component of the armature magnetic flux flow through the rotor winding 22. By optimizing the number of poles p of the rotor 2 having magnetic poles excited by the induced current, it is possible to realize a harmonic induction type synchronous rotating electrical machine that can obtain a larger torque.

  The present invention can be applied to a harmonic induction type synchronous rotating electrical machine.

1: Rotating electrical machine 2: Rotor 3: Stator 21: Rotor core 21a: Protrusion 22: Rotor winding 31: Stator core 31a: Teeth 31b: Slot 32: Stator winding 100: Diode (rectifier element)
Kw: Winding coefficient c, m: Natural number nd: Number of elements p: Number of poles q: Number of windings per pole pair per phase s: Number of slots

Claims (3)

Having a stator and a rotor arranged opposite to each other;
The stator has a stator core in which a plurality of slots are formed at intervals in the rotation direction of the rotor, and a three-phase stator winding wound around each tooth between the adjacent slots,
The stator winding is wound in a winding manner in which windings wound around different teeth and wound around different teeth are not overlapped in the rotation direction.
The rotor includes a rotor core in which a plurality of protrusions protruding toward the stator are formed at intervals in the rotation direction, rotor windings wound around the protrusions, and the rotor windings. A rectifying element that rectifies the current flowing in the line in a predetermined direction,
A magnetic pole having a polarity in which each protrusion is excited and fixed by an induced current that is induced in the rotor winding by a harmonic component of the armature magnetic flux from the stator winding and flows in one direction by the rectifying element. A rotating electric machine,
In the stator and the rotor, s is a multiple of 3 and p is an even number, where s is the number of slots that is the number of slots in the rotation direction, and p is the number of poles that is the number of magnetic poles in the rotation direction. ,
0.5 ≦ (2s / 3p) <1
A rotating electrical machine configured to satisfy The number of the rectifying elements provided in the rotor is an equation represented by using the number of poles p, the number of slots s, and a natural number m,
3m x (p / s)
The rotating electrical machine according to claim 1, wherein the value is a number that is the smallest even number.   The stator and the rotor have the number of slots and the poles so that a winding coefficient indicating an effective utilization rate in the stator of a field magnetic flux provided from the rotor is 1 or less. The rotating electrical machine according to claim 1 or 2, wherein a number is set.

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