JP2009026995A - Reactor core and reactor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reactor increasing inductance, without increasing its section and constituting very small noise and vibrations at driving, and to provide a reactor core that constitutes the reactor. <P>SOLUTION: In a reactor core 10 of an almost annular shape in plan view, two U-shaped cores 1, 1 (first cores) and a plurality of I-shaped cores 2, ..., (second cores) are disposed with gaps therebetween and the I-shaped cores 2, ..., are interposed between the two U-shaped cores 1, 1, and the sectional height of the U-shaped core 1 which is orthogonal to the direction of the magnetic path is relatively larger than that of the I-shaped core 2 in height. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a reactor core and a reactor.

  A reactor of a power conversion circuit is generally housed in a housing in a posture in which coils are formed at two longitudinal portions of a substantially circular annular reactor in plan view. This reactor core is composed of multiple cores of magnetic steel sheets or split cores consisting of dust cores. A gap plate made of nonmagnetic material is interposed between each split core, and the gap plate and core are bonded. Reactors are formed by adhesive bonding with an agent. More specifically, as shown in FIG. 15, a core a having a substantially U shape in plan view (U type core) and a core b having a rectangular shape in plan view (I type core) are bonded via a gap plate c. The coil e is formed in the longitudinal part. As a conventional example of a reactor core having such a configuration, for example, a reactor core disclosed in Patent Document 1 can be cited.

  In conventional reactors including Patent Document 1, the height of the U-shaped core in a side view and that of the rectangular core (I-shaped core) are both set to the same height.

  By the way, the present inventors applied a current to the reactor core to form an annular magnetic path, analyzed the magnetic flux density distribution inside the U-shaped core, and the result is shown in FIG. In the figure, the magnetic flux density in the region B on the annular inner peripheral surface of the U-shaped core forming the reactor core is the highest, and the magnetic flux density in the region A on the annular outer peripheral surface of the U-shaped core is extremely small. This means that the outer peripheral portion of the U-shaped core has a coarser magnetic flux density than the inner peripheral portion, and hardly contributes to the inductance performance.

  For example, when the reactor core is formed from a powder magnetic core, the magnetic permeability is lower than that formed from a magnetic steel sheet laminate, and the magnetic flux tends to concentrate on the annular inner peripheral side as described above. However, since the cross section on the inner peripheral side is constant, magnetic saturation is likely to occur, and the inductance drops sharply due to magnetic saturation. On the other hand, it is not necessary to increase the cross section of the reactor core. In this case, the reactor core itself is enlarged, and the current development direction of downsizing the reactor is reversed. Therefore, the issue of how large inductance can be obtained without increasing the cross section of the reactor core is a major issue in the reactor field in relation to the increase in applied current when the driving force of the vehicle is increased. One.

  By the way, the present inventors have analyzed the vibration mode when a current is applied to the reactor core composed of a dust core. As a result, when the bending rigidity of the reactor core, particularly the bending rigidity at the above-mentioned longitudinal portion, is low, a resonance point is generated in the vicinity of the driving frequency in the mode shape as shown in FIG. 5 (dotted line in FIG. 5). The vibration when the reactor is driven becomes large. In the vibration mode shown in FIG. 5 (repetition between the state where the reactor is contracted and the state where the reactor is extended), the coil forming portion (point P in the figure) becomes a fixed point during driving vibration, which is a so-called vibration node. On the other hand, the portion of the U-shaped core is a portion that vibrates greatly, which is a so-called vibration belly. This resonance vibration is transmitted to the housing, and the vibration of the entire reactor becomes large, and the generation of noise due to this vibration becomes a problem. This phenomenon of reducing the natural frequency of the reactor core and approaching the drive frequency has been found to be significant when the reactor core is molded from a dust core.

  As another conventional technique, there is a reactor core disclosed in Patent Document 2. Focusing on the fact that the magnetic flux density on the inner peripheral side of the annular reactor is dense, this reactor core has a high magnetic permeability on the inner peripheral side of the reactor core in order to make the magnetic flux density uniform throughout the core cross section. This is a reactor core that uses a magnetic core and a dust core with a low permeability on the outer peripheral side.

JP 2005-347626 A JP 2006-147634 A

  According to the reactor of Patent Document 2, the magnetic flux density in the core cross section can be made uniform, and the average magnetic flux density in the entire core cross section can be improved. However, molding all U-type and I-type cores from two types of dust cores having different magnetic permeability makes the production extremely complicated and significantly reduces the production efficiency. In addition, the problem of large vibration caused by the maximum amplitude near the center of the core longitudinal portion and the problem of reactor noise cannot be solved.

  The present invention has been made in view of the above problems, and provides a reactor capable of increasing its inductance without enlarging its cross section without increasing its cross section, and a reactor core constituting the reactor. The purpose is to do. It is another object of the present invention to provide a reactor with very little noise and vibration during driving of the reactor and a reactor core constituting the reactor.

  In order to achieve the above object, a reactor core according to the present invention includes two first cores that are substantially U-shaped in plan view and have magnetism, and a plurality of second cores that are rectangular in plan view and have magnetism are gaps. In the reactor core which is disposed through the two first cores and has a substantially annular shape in plan view, the height of the cross section of the first core, and the magnetic path The height in the direction orthogonal to the direction is shaped to be relatively higher than the height of the second core.

  The reactor core of the present invention has two first cores (U-shaped cores) that are substantially U-shaped in plan view and have magnetism, and a plurality of second cores (I-type cores) that are rectangular in plan view and have magnetism. The reactor is arranged through a gap and has a substantially annular shape in plan view as a whole. The first and second cores may be formed from a powder magnetic core formed by pressure-molding a magnetic powder in which a soft magnetic metal powder or a soft magnetic metal oxide powder is coated with a resin binder. However, the form formed from the dust core is preferable because it can easily cope with various design changes. The gap is formed from an air gap or a nonmagnetic gap plate.

As the soft magnetic metal powder, iron, iron-silicon alloy, iron-nitrogen alloy, iron-nickel alloy, iron-carbon alloy, iron-boron alloy, iron-cobalt alloy, iron- Phosphorus alloys, iron-nickel-cobalt alloys, iron-aluminum-silicon alloys, and the like can be used. The gap plate can be formed of ceramics such as alumina (Al ₂ O ₃ ) or zirconia (ZrO ₂ ).

  In the reactor core of the present invention, in the U-type core (first core), the height of the cross section facing the I-type core (second core) is formed higher than the height of the cross-section of the opposing I-type core. is doing. Here, the height of the cross section is a height in a side view of the substantially annular reactor core, and means a height in a direction perpendicular to the magnetic path in the U-shape.

  As described above, when the reactor core is formed from a dust core, the magnetic flux tends to concentrate on the inner circumference side of the annular shape. In particular, the length direction of the magnetic flux changes in the U-shaped core. As a result, the tendency of the magnetic flux to concentrate inside becomes prominent.

  On the other hand, since there is almost no flow of magnetic flux in the outer peripheral portion of the U-shaped core, in the present invention, the cross-sectional area (or volume) of the U-shaped core itself is not changed in order to secure the initial inductance. The volume of the part is added to the inner peripheral side. Note that the U-core cross-sectional area for securing the initial inductance mentioned here means that the U-type core and I-type core require a minimum cross-sectional area corresponding to the inductance in order to obtain a desired inductance. Therefore, it is assumed that a minimum cross-sectional area for obtaining this inductance is secured. As for the cross-sectional shape of the conventional reactor core, both the U-shaped core and the I-shaped core are rectangular (including a square), and the height and width of both cores are formed to the same dimensions.

  In the reactor core of the present invention, in order to increase the cross-sectional area of the U-shaped core, particularly on the inner peripheral side, the cross-sectional area of the U-core is not changed and the outer peripheral volume portion is added to the inner peripheral side. As a result, the cross-sectional height is larger than the cross-sectional height of the U-shaped core having the conventional structure (instead, the width from the outer peripheral side to the inner peripheral side is reduced). Therefore, it is a shape feature that the cross-sectional height of the U-shaped core is relatively larger than the cross-sectional height of the I-shaped core. The cross-sectional shape of the U-shaped core is, for example, a vertically long rectangle.

  According to the reactor of the present invention, the cross-sectional area of the U-shaped core is increased and the width of the U-shaped core is increased compared to the conventional U-shaped core, thereby increasing the cross-sectional area on the inner peripheral side, thereby preventing magnetic saturation. The characteristics can be improved, and a larger inductance can be obtained.

  Further, since the cross-sectional width of the U-shaped core is reduced, the length of the entire reactor core can be reduced, and the reactor can be reduced in size. In the conventional reactor, the top (and bottom) of the coil is located at a position higher (and lower) than the height of the U-shaped core, and the height of the reactor is defined by the height of the coil. It had been. However, in the reactor core of the present invention, by increasing the cross-sectional height of the U-shaped core to, for example, the coil height, the core material can be arranged in a region that has been a dead space so far, Effective use of the dead space can be realized without causing an increase.

  Furthermore, the center of gravity of the U-shaped core can be brought close to the center of gravity of the entire reactor core by reducing the width of the U-shaped core and increasing its cross-sectional height. This leads to a reduction in the amplitude of the U-shaped core, which is the antinode of vibration when the reactor is driven, and it can be expected that the entire reactor will have a vibration reduction effect and a noise reduction effect resulting therefrom.

  Generally, an increase in the core weight of the reactor core increases the manufacturing cost, but the reactor core according to the present invention does not change the cross-sectional area of the core, that is, does not change the volume and weight of the core. Since only the vertical and horizontal dimensions of the cross section are adjusted, the manufacturing complexity is not brought about, and the manufacturing cost is not increased.

  Another embodiment of the reactor according to the present invention includes two first cores that are substantially U-shaped in plan view and have magnetism, and a plurality of second cores that are rectangular in plan view and have magnetism. In a reactor core that is disposed via a gap and is interposed between the two first cores and has a substantially annular shape in plan view, both the first core and the second core are substantially annular. The height of the inner peripheral side for forming is relatively high compared to the height of the outer peripheral side.

  In the reactor core of the present invention, the cross-sectional shapes of both the I-type core (second core) and the U-type core (first core) are shaped so that the inner peripheral side of the ring is high and the outer peripheral side is relatively low, The outer edge is formed into a trapezoidal shape (or a substantially trapezoidal shape).

  Also in this embodiment, it is still necessary to provide both the I-type core and the U-type core with the minimum cross-sectional area necessary for securing the initial inductance. When the trapezoidal core cross section is satisfied while satisfying this condition, there are two more specific cross-sectional forms. One of them is a form (herein referred to as the first form) in which the height of the inner peripheral side is increased without increasing the width of the core (distance from the inner peripheral side to the outer peripheral side). One is a configuration in which the height of the inner peripheral side is relatively increased while the width of the core is increased (therefore, the height on the inner peripheral side is reduced as compared with the first configuration) (here, (Referred to as a second form).

  In the case of the first embodiment, as described above, the inner peripheral side is less likely to be magnetically saturated, and the magnetic saturation resistance of the reactor core is improved.

  On the other hand, in the case of the second embodiment, the increase in width increases the second moment of inertia of the core (thus increasing the bending rigidity of the core), reducing the vibration of the reactor and reducing the noise caused thereby. An effect is obtained.

  According to the reactor of the present invention described above, the magnetic resistance can be increased by simply adjusting the cross-sectional shape (height, width, shape) of the core material without increasing its weight (and thus increasing the manufacturing cost). Since the saturation characteristics can be improved and the inductance can be increased, it is possible to cope with a higher output of the drive motor.

  In addition, as described above, the bending rigidity of the reactor core can be increased by adjusting the cross-sectional shape of the core, thereby reducing the vibration and noise when the reactor is driven.

  Therefore, the production of such a high-performance reactor has recently been expanded, and is suitable for a hybrid vehicle in which the running performance of the vehicle and the low noise environment in the vehicle interior are required.

  As can be understood from the above description, according to the reactor core and the reactor of the present invention, the inductance is increased and the noise and vibration during driving are reduced only by adjusting the cross-sectional shape of the core without increasing the manufacturing cost. Can be achieved.

  Embodiments of the present invention will be described below with reference to the drawings. 1 is a schematic perspective view of a first embodiment of a reactor core according to the present invention, FIG. 2a is a longitudinal sectional view of a part of a conventional reactor core, and FIG. 2b is a diagram of the reactor core according to the present invention shown in FIG. It is a partial longitudinal cross-sectional view. FIG. 3 is a schematic perspective view of the first embodiment of the reactor of the present invention having the reactor of FIG. 1, and FIG. 4 is a graph comparing the inductance characteristics of the conventional reactor and the reactor of the present invention shown in FIG. is there. FIG. 5 is a graph showing the relationship between the driving frequency (frequency) of the reactor device and each natural frequency (frequency) of the conventional reactor and the reactor of the present invention, and FIGS. It is a schematic perspective view of this embodiment. FIG. 8 is a schematic perspective view of another embodiment of the reactor door of the present invention, FIG. 9 is a side view of the reactor door of FIG. 8, and FIG. 10 is a reactor of the present invention including the reactor door of FIG. FIG. 11 is a schematic perspective view of the fourth embodiment, and FIGS. 11 and 12 are cross-sectional views illustrating a cross-sectional form of an I-type core in the reactor core of FIG. FIG. 13 is a graph comparing the inductance characteristics of the conventional reactor and the reactor of the present invention shown in FIG. FIG. 14 is a schematic block diagram of a motor drive device provided with the reactor device of the present invention. In the illustrated example, the gap plate between the cores is not shown. Furthermore, in the example of illustration, a part of coil which comprises a reactor is fractured | ruptured and shown in figure.

  FIG. 1 is a perspective view showing a first embodiment of a reactor core according to the present invention. In this reactor core 10, three I-type cores 2, 2, and 2 are arranged in the space between two U-type cores 1 and 1 arranged at a predetermined distance. A gap plate (not shown) is disposed between the cores 2 and between the I-type cores 2 and 2 via an adhesive layer to form a reactor ring that is substantially annular in plan view.

  The U-type core and I-type core are powder magnets formed by pressure-molding a laminate formed by laminating electromagnetic steel sheets, or a magnetic powder coated with a soft magnetic metal powder or soft magnetic metal oxide powder with a resin binder. Although formed from a core, in the illustrated example, each core is formed from a dust core.

  The U-shaped core 1 is formed by integrally forming a general portion 11 having the same height as the I-shaped core 2 and raised portions 12 and 12 raised above and below the U-shaped core 1. The raised portion 12 is originally a portion provided at the end of the general portion 11 raised to the illustrated position, and the cross-sectional area of the I-type core 2 (the cross-sectional area perpendicular to the magnetic path direction) and the U-type The cross-sectional area of the core 1 has the same area.

  FIG. 2 is a diagram for explaining the above contents. FIG. 2a shows the level relationship of the conventional U-type core 1 ′, I-type core 2 and coil 3, and there is a dead space S corresponding to the thickness of the coil outside the coil 3 (U-type core side). It was happening.

  Therefore, by making the reactor core of the present invention shown in FIG. 2b, the end portion of the U-shaped core is cut and the portion corresponding to the volume is provided as the raised portion above and below the general portion. As a result, the length direction of the reactor core is obtained. Is shortened by t2 (thus, the entire reactor core is shortened by 2 × t2), and the raised portion (height: t1) is added to the dead space to effectively use this space and not to exceed the original coil height. There is no need to increase the size of the reactor in the height direction.

  By forming the coils 3 and 3 in the longitudinal part of the reactor core 10 shown in FIG. 1, the reactor 100 of this invention shown in FIG. 3 is formed. In the illustrated example, a part of the front coil is cut away.

  By increasing the height of the U-shaped core 1, it is possible to increase the height of the inner peripheral side as compared with the conventional U-shaped core of a reactor core, and thus to take a larger sectional area on the inner peripheral side. Therefore, it is possible to improve the inductance performance of the reactor, in which magnetic saturation easily occurs particularly on the inner peripheral side of the U-shaped core. FIG. 4 shows a graph showing the relationship between the superimposed current and inductance of both the conventional reactor and the reactor of the illustrated example. In the figure, X1 indicates the case of the reactor of the present invention, and X2 indicates the case of the conventional reactor.

  The reactor of the present invention is mainly used for mounting in a hybrid vehicle or the like, and the normal superimposed current range in this case is about 0 to 200A. As a result of verifying the inductance in this superposed current range, it was found that the inductance can be increased by about 5 to 10% by increasing the height of the U-shaped core as compared with the conventional reactor core while keeping the cross-sectional area constant. Yes.

  6 and 7 are perspective views showing other embodiments 2 and 3 of the reactor of the present invention. Reactor 100A shown in FIG. 6 has U-shaped core 1A in a form in which the upper and lower portions on the outer peripheral side of U-shaped core are cut and the volume is further added to the inner peripheral side as compared with reactor 100 in FIG. The reactor is designed to obtain a larger inductance by taking a larger height (cross-sectional area) on the inner peripheral side.

  On the other hand, the reactor 100B shown in FIG. 7 has a U-shaped core 1B in which the width of the U-shaped core (the length from the inner peripheral side to the outer peripheral side) is made shorter than that of the reactor 100A. This is a reactor designed to further reduce the size of the reactor.

  FIG. 8 is a view showing Embodiment 2 of the reactor according to the present invention, and FIG. 9 is a side view thereof. In the reactor core 10A, both the I-type core 2A and the U-type core 1C are formed such that the height of the annular inner peripheral side is higher than the height of the outer peripheral side. FIG. 10 shows a reactor 100 </ b> C in which coils 3 and 3 are formed in the longitudinal portion.

  Here, there are two types of cross-sectional shapes of each core, and FIGS. 11 and 12 explain them.

  FIG. 11 shows a cross-sectional form 1 of the I-type core 2A. In this form, the width (length from the inner peripheral side to the outer peripheral side) of the original rectangular cross section (or square cross section) is made constant. The height on the inner peripheral side: t3 is increased, and the height on the outer peripheral side: t4 is decreased so as to have the same area as the initial cross-sectional area. In this cross-sectional form, particularly the inductance performance of the reactor core can be enhanced, and as shown in FIG. 13, the inductance can be made larger than that of the conventional reactor core (Y2) (the present invention is Y1). A large drop current can be obtained.

  On the other hand, FIG. 12 shows a sectional form 2 of the I-type core 2A. In this configuration, the height of the initial rectangular cross section: t5 is kept constant, and the core width: t6 is increased to increase the cross sectional secondary moment of the core, thereby increasing the bending rigidity of the core. It is.

  As a result, the natural frequency of the reactor core and the drive vibration can be kept away, and the occurrence of resonance vibration can be prevented and the generation of noise due to this can be suppressed.

In addition, when each core material constituting the reactor core is formed from a dust core, the rigidity of the reactor core itself is remarkably reduced as compared with the case where it is formed from a magnetic steel sheet laminate, and as a result, the dotted line in FIG. The natural frequency of the reactor core as shown by: f _peak and the drive frequency of the device: f ₀ approach each other. Therefore, by increasing the bending rigidity of the reactor core, the natural frequency: f _peak can be moved away from the driving frequency: f _0, and the occurrence of resonance vibration or the like can be suppressed as described above.

  FIG. 14 is a schematic block diagram of a motor drive device equipped with the reactor 100 described above.

  The motor driving apparatus shown in the figure is generally composed of a DC power supply B, system relays SR1 and SR2, a capacitor C1, a boost converter C, inverters I1 and I2, and a control unit (not shown).

  AC motors M1 and M2 are torque generating motors for driving driving wheels of a hybrid vehicle or the like, and are three-phase (U-phase, V-phase, W-phase) permanent magnet motors.

  Boost converter C includes a reactor device 100, NPN transistors Q1 and Q2, and diodes D1 and D2.

The direct current power source B is composed of a secondary battery such as lithium ion or nickel metal hydride.
System relays SR1 and SR2 are turned on by a logic high level signal and turned off by a logic low level signal.

  Further, the voltage from the DC power supply B is smoothed by the capacitor C1, and the smoothed DC voltage is provided to the boost converter C. In step-up converter C, the DC power supply B is charged by stepping down the DC voltage supplied from inverters I1 and I2 in response to a command signal from the control unit.

  According to the motor drive device equipped with the reactor 100 of the present invention described above, since noise and vibration from the reactor 100 are extremely small, this is not transmitted (or less) into the vehicle interior. It is suitable for the recent hybrid vehicle etc. in which low noise environment is important. Further, since the inductance can be increased as compared with the conventional reactor, it is possible to cope with higher-power motor driving.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and there are design changes and the like without departing from the gist of the present invention. They are also included in the present invention.

1 is a schematic perspective view of a first embodiment of a reactor core according to the present invention. (A) is a longitudinal cross-sectional view of a part of a conventional reactor core, and (b) is a longitudinal sectional view of a part of the reactor core of the present invention shown in FIG. It is a schematic perspective view of Embodiment 1 of the reactor of the present invention comprising the reactor core of FIG. It is the graph which compared the inductance characteristic of the conventional reactor and the reactor of this invention shown in FIG. It is the graph which showed the relationship between the drive frequency (frequency) of a reactor apparatus, and each natural frequency (frequency) of the conventional reactor and the reactor of this invention. It is a schematic perspective view of Embodiment 2 of the reactor of this invention. It is a schematic perspective view of Embodiment 3 of the reactor of the present invention. It is a schematic perspective view of Embodiment 2 of the reactor core of the present invention. It is a side view of the reactor door of FIG. FIG. 9 is a schematic perspective view of a reactor according to a fourth embodiment of the present invention that includes the reactor of FIG. 8. It is sectional drawing explaining the cross-sectional form 1 of the I-type core in the reactor core of FIG. It is sectional drawing explaining the cross-sectional form 2 of the I-type core in the reactor core of FIG. It is the graph which compared the inductance characteristic of the conventional reactor and the reactor of this invention shown in FIG. It is a schematic block diagram of the motor drive device provided with the reactor apparatus of this invention. It is a schematic plan view of the conventional reactor. It is a figure which shows the magnetic field analysis result in the U-shaped core of the conventional reactor.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... U-type core (1st core), 11 ... General part, 12 ... Raised part, 2 ... I-type core (2nd core), 3 ... Coil 10, 10A ... Reactor core, 100, 100A, 100B , 100C ... Reactor, S ... Dead space

Claims (3)

Two first cores having a substantially U shape in plan view and having magnetism are provided, a plurality of second cores having a rectangular shape in plan view and having magnetism are disposed via a gap, and the two first cores are disposed. In the reactor core that is interposed between the cores, and has a substantially annular plan view,
Reactor characterized in that the height of the cross section of the first core and the height in the direction perpendicular to the magnetic path direction is relatively higher than the height of the second core core. Two first cores having a substantially U shape in plan view and having magnetism are provided, a plurality of second cores having a rectangular shape in plan view and having magnetism are disposed via a gap, and the two first cores are disposed. In the reactor core that is interposed between the cores, and has a substantially annular plan view,
The reactor core is characterized in that both the first core and the second core are formed such that a height on the inner peripheral side forming the substantially annular shape is relatively higher than a height on the outer peripheral side.   A reactor comprising the reactor core according to claim 1, wherein a coil is formed on an outer periphery of the second core.

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