JP2011146605A - Electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic apparatus that logically calculates optimum hardness of an elastic material inserted into a gap between iron cores to reduce noise not only in a leg direction but also in a yoke direction and in a thickness direction. <P>SOLUTION: The electronic apparatus 1 formed by interposing a spacer 3 made of the elastic material in an intermediate portion of an iron core 2 extended by magnetostriction in a magnetic flux direction is characterized in that the spacer 3 is arranged such that an amount of deformation of the spacer 3 due to electromagnetic force of the iron core 2 matches an amount of magnetostriction of the iron core 2 caused by magnetic flux generated by the electromagnetic coil. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electric device that reduces noise by a spacer made of an elastic material disposed between iron cores.

  As a method of reducing the noise of electrical equipment, a method of increasing the cross-sectional area of the iron core to reduce the magnetic flux density, reducing the vibration source, and a method of absorbing electricity by enclosing electricity in a metal case are used. . However, when the cross-sectional area of the iron core is increased, the amount of the iron core increases, which causes a problem in terms of cost and device size reduction. In addition, when enclosing with a metal case, a thick metal case is required, which similarly causes problems in terms of cost and downsizing of the device.

Therefore, a technique for reducing noise without increasing the iron core amount is disclosed (see Patent Documents 1 to 4). The technique shown in Patent Document 1 uses a member having a high Young's modulus for an insulating spacer that forms a gapd iron core, thereby suppressing vibration of the iron core and reducing noise and vibration. A spacer is formed from, for example, a polyester molded product formed by adding an additive such as silicon, and the Young's modulus of the spacer is adjusted to 1.5 to 5.0 × 10 ⁵ kg / cm ² by adjusting the material and amount of the additive. In this case, the amplitude is about 25 μm or less. The point with the smallest amplitude is obtained when the Young's modulus is around 3.0 × 10 ⁵ kg / cm ² .

  The technique shown in Patent Document 2 includes a pair of cores that have a U-shape in a side view and are opposed to each other and that are joined to each other using an adhesive, and at least one of the cores. It is a flyback transformer made of an elastic material and having a gap spacer plate whose thickness is adjusted by being pressed between the legs, and the assembly method according to the present invention includes the legs And a step of curing the adhesive in a state where a core in which a gap spacer plate made of an elastic material is interposed between at least one leg is pressed along the opposing direction. It is a waste.

  The technique shown in Patent Document 3 includes a core composed of two straight portions and two curved portions, and a coil wound around each straight portion of the core. Two or more gaps are provided in each linear portion of the core. The straight portion core body of the straight portion separated by each gap and the curved portion core body respectively positioned at the curved portion are fixed via a gap member made of a highly elastic material disposed in the gap. Each bending portion core body is fixed to the housing case, and the distance between both bending portion core bodies is kept constant.

The technique shown in Patent Document 4 is made of a silicon steel plate having a magnetostriction at DC of −1.5 × (1/10 ⁶ ) to 1.5 × (1/10 ⁶ ), and abutting portions between core constituent members More preferably, the bolted portion and the gap portion of the core are bonded with an adhesive having an adhesive strength of 100 kgf / cm ² or more, and are bonded and coiled between the laminated steel plates by varnish impregnation, more preferably the end face of the core Are welded in the stacking direction of the steel plates. Further, depending on the size of the gap, a spacer made of a non-magnetic material having a hardness Hv: 50 or more is inserted into the gap portion, and the spacer and the core constituent member are bonded together with an adhesive having the above-described adhesive strength. As a result, vibration due to various factors of the core is remarkably reduced, and noise is effectively reduced.

JP 58-131720 A JP 9-102430 A JP 2006-351679 A JP-A-8-111322

  However, the Young's modulus shown in Patent Document 1 may not be applicable when conditions (for example, iron core length, cross-sectional area, magnetic flux density, strain amount, spacer elastic modulus, thickness, etc.) are different, It cannot respond flexibly according to various shapes and uses.

  In addition, the techniques shown in Patent Documents 2 and 3 do not show a clear calculation method for the appropriate value of the elastic material in the gap, and cannot respond flexibly according to various diversified shapes and applications. Absent.

  Furthermore, since the techniques shown in Patent Documents 1 to 4 do not consider vibrations in the yoke direction and the thickness direction, noise reduction is not a sufficient technique.

  Therefore, the present invention logically calculates the optimum hardness of the elastic material inserted into the gap between the iron cores, and reduces noise in the entire device by reducing not only the leg direction but also the yoke direction and the thickness direction. And electrical equipment capable of suppressing vibration.

  The electrical device disclosed in the present application is an electrical device that is formed by inserting a spacer made of an elastic material in an intermediate portion of an iron core that is inserted through an electromagnetic coil and extends in a magnetic flux direction due to magnetostriction. The amount of deformation of the spacer due to the electromagnetic force of the iron core is arranged to match the amount of magnetostriction of the iron core due to the magnetic field generated by the coil.

  As described above, the electrical device disclosed in the present application matches the amount of magnetostriction distortion of the iron core due to the magnetic field generated by the electromagnetic coil and the amount of deformation of the spacer due to the electromagnetic force of the iron core, thereby The shape change (stretching in the magnetic flux direction) can be offset by the deformation of the spacer by electromagnetic force (shrinkage in the magnetic flux direction due to the attraction force) to suppress the vibration of the iron core surface, greatly reducing the noise of electrical equipment. There is an effect that it can be suppressed.

  The electric device disclosed in the present application is characterized in that the spacer is disposed in a middle portion of the iron core leg portion and the yoke portion in a direction orthogonal to the magnetic flux generated by the electromagnetic coil. .

  As described above, since the spacer is arranged in the direction perpendicular to the magnetic flux in the intermediate portion of the iron core leg portion and the yoke portion in the electric device disclosed in the present application, not only the noise due to vibration in the leg direction but also the yoke. The noise due to the vibration in the direction is also reduced, and the noise can be greatly reduced as the entire electric equipment.

In the electrical device disclosed in the present application, the Young's modulus E _{1 of the} spacer disposed in the direction orthogonal to the magnetic flux is

(However, α: constant (constant according to the material of the iron core), L _t : length of the central axis of the iron core (excluding spacer thickness), μ _g : permeability of spacer, G _t : thickness of spacer And the like.

Thus, electrical equipment disclosed in the present application, by calculating the optimum Young's modulus of the spacer E ₁ according to the above equation, depending on the electrical equipment of various shapes and applications diversifying correspond flexibly In addition, by arranging the spacer with an optimal Young's modulus, it is possible to reliably suppress the vibration of the iron core surface and greatly reduce the noise.

  The electric device disclosed in the present application is characterized in that the spacer is arranged on the leg portion and the yoke portion of the iron core in a direction parallel to the magnetic flux generated by the electromagnetic coil.

  As described above, in the electrical device disclosed in the present application, since the spacer is disposed in the direction parallel to the magnetic flux in the iron leg portion and the yoke portion, not only the noise due to the vibration in the leg direction but also the vibration in the thickness direction. This also reduces the noise caused by the noise and greatly reduces the noise of the entire electrical equipment.

In the electric device disclosed in the present application, the Young's modulus E _{2 of the} spacer disposed in a direction parallel to the magnetic flux is

(However, β: constant (constant according to iron core material), L _t : iron core thickness (excluding spacer thickness), μ _g : spacer permeability, G _t : spacer thickness) It is characterized by being.

As described above, the electrical device disclosed in the present application is capable of adapting flexibly according to various diversified shapes and uses of electrical devices by calculating the optimum Young's modulus E ₂ of the spacer by the above formula. In addition, by arranging the spacer with an optimal Young's modulus, it is possible to reliably suppress the vibration of the iron core surface and greatly reduce the noise.

  The electrical device disclosed in the present application is characterized in that the spacer includes a plurality of layers, and the thickness and / or material of each of the plurality of layers is different.

  As described above, the electrical device disclosed in the present application is more effective by forming a spacer having an optimal Young's modulus because the spacer includes a plurality of layers, and the thickness and / or material of each of the plurality of layers is different. In addition, there is an effect that noise can be reduced.

  The electrical device disclosed in the present application is a three-phase transformer or a three-phase reactor, and the magnetic resistance of the spacer disposed on the leg portion in the V phase has a leg portion in the U phase or the W phase. And the total value of the magnetic resistances of the spacers arranged in the yoke portion.

  As described above, in the electric device disclosed in the present application, the electric device is a three-phase transformer or a three-phase reactor, and the magnetic resistance of the spacer disposed on the leg portion in the V phase is in the U phase or the W phase. Since it is the total value of the magnetic resistance of the spacers arranged in the leg part and the yoke part, it is possible to maintain the balance of the three-phase magnetic resistance and to function correctly as a three-phase transformer or a three-phase reactor. There is an effect.

  The electric device disclosed in the present application is characterized by including a fixture for fixing the iron core in the leg direction, the yoke direction, and / or the thickness direction of the electric device.

  As described above, since the electrical device disclosed in the present application includes the fixing device that fixes the iron core in the leg direction, the yoke direction, and / or the thickness direction of the electrical device, the function of the spacer is sufficient due to a change in the current value or the like. Even when a situation that is not realized in the above occurs, it is possible to suppress a certain amount of vibration by the fixture and to minimize the generation of noise.

It is a figure which shows the displacement by the electromagnetic force of the iron core in the electric equipment which concerns on 1st Embodiment. It is a figure which shows the displacement by the magnetostriction of the iron core in the electric equipment which concerns on 1st Embodiment. It is a figure which shows the displacement by the electromagnetic force and magnetostriction in the electric equipment which concerns on 1st Embodiment. It is a 1st figure which shows the example of arrangement | positioning of the spacer in the electric equipment which concerns on 1st Embodiment. It is a 2nd figure which shows the example of arrangement | positioning of the spacer in the electric equipment which concerns on 1st Embodiment. It is a 3rd figure which shows the example of arrangement | positioning of the spacer in the electric equipment which concerns on 1st Embodiment. It is a figure which shows a mode in the case of inserting a spacer in the electric equipment which concerns on 1st Embodiment. It is a whole perspective view at the time of providing a fixing tool in the electric equipment concerning a 1st embodiment. It is a figure which shows the analysis model of the reactor which concerns on an Example, and the example of arrangement | positioning of a gap. It is the figure which showed the electric current in the coil under the power supply in the reactor which concerns on an Example in the time domain and the frequency domain. It is a figure which shows the displacement distribution by a normal type single phase reactor at the time of adding a soft gap. It is a figure which shows the displacement distribution by a normal type single phase reactor at the time of adding a hard gap. It is a figure which shows the displacement distribution by the proposal type single phase reactor at the time of adding a hard gap. It is a figure which shows the frequency spectrum of the total force quantity of the electromagnetic force and magnetostriction in the point s. It is the figure which expressed the frequency spectrum of y component of displacement in point p by μm and dB. It is the figure which represented the frequency spectrum of the x component of the displacement in the point q by micrometer and dB. It is a figure which shows an experimental apparatus.

  Embodiments of the present invention will be described below. The present invention can be implemented in many different forms. Therefore, the present invention should not be construed based only on the description of the present embodiment. Also, the same reference numerals are given to the same elements throughout the present embodiment.

(First embodiment of the present invention)
An electrical apparatus according to this embodiment will be described with reference to FIGS. FIG. 1 is a diagram showing displacement due to electromagnetic force of an iron core in the electric device according to the present embodiment, FIG. 2 is a diagram showing displacement due to magnetostriction of the iron core in the electric device according to the present embodiment, and FIG. The figure which shows the displacement by the electromagnetic force and magnetostriction in the electric equipment which concerns on this embodiment, FIG. 4 is the 1st figure which shows the example of arrangement | positioning of the spacer in the electric equipment which concerns on this embodiment, FIG. FIG. 6 is a third diagram illustrating an example of the arrangement of spacers in the electrical device according to the present embodiment, and FIG. 7 is an electrical device according to the present embodiment. FIG. 8 is a perspective view of the electrical apparatus according to the present embodiment when a fixture is provided.

  FIG. 1 shows the displacement of the iron core due to electromagnetic force, FIG. 1 (A) shows the displacement in the magnetic flux direction of the iron core due to electromagnetic force, and FIG. 1 (B) shows the magnetic flux of the iron core due to electromagnetic force. It is a figure which shows the displacement of the direction perpendicular | vertical to a direction. In FIG. 1 (A), a gap is formed between the iron cores 2 in the electrical equipment 1 and a spacer 3 is inserted. The spacer 3 is an insulator made of an elastic material. When a magnetic flux is applied by an electromagnetic coil (not shown), an attractive force is generated by the electromagnetic force between the iron cores 2 and the respective iron cores 2 attract each other. Since the spacer 3 is made of an elastic material, the position of the iron core is displaced in the direction of the arrow a in FIG. 1A, and the electric device 1 contracts in a direction parallel to the magnetic flux direction.

  In the case of FIG. 1B as well, a spacer 3 made of an elastic material is inserted between the iron cores 2. When a magnetic flux is applied by an electromagnetic coil (not shown), a repulsive force is generated by the electromagnetic force between the iron cores 2 and the respective iron cores 2 are separated. Since the spacer 3 is made of an elastic material, the position of the iron core is displaced in the direction of the arrow b in FIG. 1B, and the electric device 1 extends in a direction perpendicular to the magnetic flux direction.

  2 shows the displacement of the iron core due to magnetostriction, FIG. 2 (A) shows the displacement of the iron core in the magnetic flux direction due to magnetostriction, and FIG. 2 (B) shows the magnetism. It is a figure which shows the displacement of the direction perpendicular | vertical to the magnetic flux direction of the iron core by distortion. As shown in FIGS. 2 (A) and 2 (B), the shape of the iron core 2 is deformed by magnetostriction, so that the electric device 1 extends in a direction parallel to the magnetic flux direction and in a direction perpendicular to the magnetic flux direction. Shrink (see arrows a and b).

  The relation between the displacement of the iron core due to the electromagnetic force and magnetostriction shown in FIGS. 1 and 2 and the spacer 3 will be described with reference to FIG. 3A shows the displacement of the iron core when the elastic modulus of the spacer 3 is small, FIG. 3B shows the displacement of the iron core when the elastic modulus of the spacer 3 is large, and FIG. The displacement of the iron core when the elastic modulus of the spacer 3 is optimized is shown.

  As shown in FIG. 3, when the elastic modulus of the spacer 3 is small, the displacement due to the electromagnetic force becomes dominant, and the iron core contracts in the magnetic flux direction due to the attractive force due to the electromagnetic force, and the magnetic flux direction due to the repulsive force due to the electromagnetic force. Will cause vibration and noise. Conversely, when the elastic modulus of the spacer 3 is large, displacement due to magnetostriction is dominant, and the iron core expands in the magnetic flux direction due to magnetostriction and contracts in the direction perpendicular to the magnetic flux direction, resulting in vibration and noise. End up. When the elastic modulus of the spacer 3 is optimized, the displacement due to the electromagnetic force and the displacement due to the magnetostriction are canceled out, so that no displacement occurs and no vibration or noise occurs. Details of the optimization of the elastic modulus of the spacer 3 will be described later.

  The electrical device according to the present embodiment can be applied to various types of electrical devices. Hereinafter, three specific examples will be described. FIG. 4 is an example of the arrangement of spacers when the electrical device according to the present embodiment is a transformer. FIG. 4A is an example when applied to a single-phase transformer, and FIG. 4B is an example when applied to a three-phase transformer. Normally, as shown in the conventional type of FIG. 4A, a gap in which an insulator is inserted is not provided in the transformer, but in this embodiment, a gap is provided in order to eliminate the displacement of the iron core.

  As shown in FIG. 4 (A), the spacers 3 are disposed in each of the leg portion, the yoke portion, and the interlayer (thickness direction) so that the iron core 3 is not displaced in each direction. . Further, in each direction, the spacers 3 can be disposed so as to be dispersed in one place or a plurality of places. As shown in FIG. 4B, in the three-phase case, as in the single-phase case, the spacer 3 is arranged so that the iron core 3 is not displaced in each direction. Again, in each direction, the spacers 3 can be arranged in a single location or a plurality of locations in each direction.

In the case of three phases, it is necessary to adjust the thickness of the spacer 3 so that the magnetic resistance is not unbalanced. Specifically, the magnetic resistance of the spacer 3 provided in the V-phase leg is adjusted so as to be the sum of the magnetic resistance provided in the U-phase or W-phase leg and the yoke part. In other words, in the case of FIG. 4 (B), adjusting the thickness of the spacer 3 so that the magnetic resistance _{R c = R l1 + R l2} + R l3.

  Each spacer 3 to be disposed may be a single-layer insulator or a multi-layer insulator. In the case of a single layer, the elastic modulus can be adjusted by changing the material, and in the case of multiple layers, the elastic modulus of the entire spacer 3 can be adjusted by adjusting the combination of different materials and the thickness of each layer. .

  FIG. 5 is an example of arrangement of spacers when the electrical apparatus according to the present embodiment is a reactor. FIG. 5A is an example when applied to a single-phase reactor, and FIG. 5B is an example when applied to a three-phase reactor. Normally, as shown in the conventional type in FIG. 5A, the reactor is provided with a gap in the leg portion in order to adjust the inductance, but in this embodiment, the yoke portion is used to eliminate the displacement of the iron core. In addition, a gap is also provided in the interlayer (thickness direction).

  As in the case of FIG. 4, the spacer 3 is disposed in each of the leg portion, the yoke portion, and the interlayer (thickness direction) so that the iron core 3 is not displaced in each direction. Further, in each direction, the spacers 3 can be disposed so as to be dispersed in one place or a plurality of places. As shown in FIG. 5B, in the three-phase case, as in the single-phase case, the spacer 3 is arranged so that the iron core 3 is not displaced in each direction. Again, in each direction, the spacers 3 can be arranged in a single location or a plurality of locations in each direction.

In the case of three phases, it is necessary to adjust the thickness of the spacer 3 so that the magnetic resistance is not unbalanced as in the case of the transformer. Specifically, as shown in FIG. the thickness of the resistance _{R c1 + R c2 + R c3} = R l1 + R l2 + R l3 + R l4 + R l5 become as spacer 3 adjusted.

  Each spacer 3 to be disposed may be a single-layer insulator or a multi-layer insulator. In the case of a single layer, the elastic modulus is adjusted by changing the material, and in the case of multiple layers, the elastic modulus of the spacer 3 as a whole is adjusted by adjusting the combination of different materials and the thickness of each layer. May be.

  FIG. 6 is an arrangement example of spacers when the electrical apparatus according to the present embodiment is a motor. As shown in FIG. 6, the spacer 3 is disposed in the same shape as the stator along the longitudinal direction in the stator, and the annular spacer 3 is disposed along the circumferential direction of the stator. The vibration and noise of the motor can be reduced.

Here, optimization of the elastic modulus of the spacer 3 will be described. FIG. 7 shows a state in which a spacer is inserted into the electric apparatus according to the present embodiment. FIG. 7A is a diagram when the spacer is inserted in a direction perpendicular to the magnetic flux, and FIG. 7B is a diagram when the spacer is inserted in a direction parallel to the magnetic flux. First, in FIG. 7A, the elongation of the iron core due to magnetostriction is u _ms , the magnetostriction of the insulator inserted as a spacer is zero, and the magnetostriction ε _ms of the iron core can be approximated by the square of the magnetic flux density. Assume that The longitudinal strain ε _{h, ms} due to magnetostriction is approximated by the following equation.

B: Magnetic flux density, α: Constant.

The displacement u _ms which is the elongation of the iron core due to magnetostriction is given by the following equation.

The shrinkage of the spacer due to the electromagnetic force acting on the gap is u _em , and the iron core is much harder than the insulator, so the shrinkage of the iron core due to the electromagnetic force is ignored, and the permeability μ _i of the iron core is the permeability μ of the insulator Assume that it is sufficiently larger than _g . The electromagnetic force σ _em acting on the gap surface is expressed by the following equation.

The longitudinal strain ε _{h, ms} of the spacer is given by the following equation.

E ₁ : Young's modulus The displacement u _em of the spacer is as follows.

From the condition u _ms = u _em where the elongation of the entire iron core is 0, the optimum Young's modulus E ₁ of the spacer is

It becomes. Next, in FIG. 7B, the contraction of the iron core due to magnetostriction is u _ms , the magnetostriction of the insulator inserted as a spacer is zero, and the magnetostriction ε _ms of the iron core can be approximated by the square of the magnetic flux density. Assume that The lateral strain ε _{l, ms} due to magnetostriction is approximated by the following equation.

B: Magnetic flux density, β: Constant.

The displacement u _ms, which is the shrinkage of the iron core due to magnetostriction, is given by the following equation.

Spacer elongation due to the electromagnetic force acting on the gap is u _em , and the iron core is much harder than the insulator, so the shrinkage of the iron core due to the electromagnetic force is ignored, and the permeability μ _i of the iron core is the permeability μ of the insulator Assume that it is sufficiently larger than _g . The electromagnetic force σ _em acting on the gap surface is expressed by the following equation.

The longitudinal strain ε _{h, ms} of the spacer is given by the following equation.

E ₂ : Young's modulus The displacement u _em of the spacer is as follows.

From the condition u _ms = u _em where the elongation of the entire iron core is zero, the optimum Young's modulus E ₂ of the spacer 3 is

When there is a relationship of ε _{l, ms} = vε _{h, ms} (v: Poisson's ratio),

  It becomes. From the above, the optimum value of the elastic modulus of the spacer can be calculated.

  FIG. 8 is an overall perspective view when the fixture is provided. As shown in FIG. 8, when the fixture is provided in at least one of the leg direction, the yoke direction, and the thickness direction, a situation occurs in which the balance between electromagnetic force and magnetostriction is lost due to a change in current value, etc. Even so, it is possible to suppress vibration and minimize noise by the fixture. Here, an example is shown in which a fixture is provided in each of two directions and three directions.

  Although the present invention has been described with the above-described embodiments, the technical scope of the present invention is not limited to the scope described in the embodiments, and various changes or improvements can be added to these embodiments.

A more specific analysis result regarding the electrical apparatus according to the present invention will be described. Here, the cause of the reactor noise at the time of power supply is investigated, and the model design for reducing noise is demonstrated.
(1. Introduction)
When a reactor is connected to an inverter power supply device, noise from the reactor is generated by the inverter generating a high frequency component. In order to clarify the mechanism of noise generation under the power supply of the inverter, 3D vibration analysis considering electromagnetic force and magnetostriction has been proposed (Reference 1: Y. Gao, K. Muramatsu, K.Shida). , K. Fujiwara, S. Fukuchi, and T. Takahata, “Vibration Analysis of a Reactor Driven by an Inverter Power Supply Considerring Electromagnetism and Magnetostriction” IEEE Trans.on Magn., Vol.45, no.10, pp.4789- 4792, 2009). Reference 1 describes the equivalent nodal force (Reference 2: K. Delaere, W. Heylen, R. Belmans, and K. Hameyer, “Comparison of induction machine stator vibration spectra induced by reluctance forces and magnetostriction,” IEEE Trans.on Magn , vol.38, no.2, pp.969-972, 2002), a design method using 3D magnetostriction has been proposed and applied to vibration analysis of a single-phase reactor under power supply.

  By obtaining the nodal force of both electromagnetic force and magnetostriction at the same level, the displacement generates noise, so it can be seen that both electromagnetic force and magnetostriction are the cause of noise. The reactor surface displacement is also a source of noise, and the hardness of the insulator inserted in the gap between the cores should be optimized to reduce the noise. Since the displacement of the yoke portion changes due to electromagnetic force and magnetostriction, adjustment of the hardness of the insulator is effective. Furthermore, the hardness of the insulation shown in the measurements affected the noise level. In the present embodiment, the noise of the reactor is reduced, and the hardness of the insulator inserted in the gap in the core in that case is determined. Therefore, in the normal configuration, the displacement on the upper surface of the yoke is reduced, and noise can be reduced. In addition, a new model of the single-phase reactor is designed, and the effect of the designed model is shown by vibration analysis and experiment.

(2. Analysis method)
(A) Magnetic field analysis A 3D eddy current finite element method analysis of the A-φ method using a magnetic field was performed. A is a magnetic vector potential, and φ is an electric scalar potential. The eddy current between metal plates is also modeled as an anisotropic massive iron core by considering the gap between them (Reference 3: Y.Gao, K.Muramatsu, K.Shida, K.Fujiwara) , S. Fukuchi, and T. Takahata, “Loss culculation of reactor connected to inverter power supply taking account of eddy currents in laminated steel core,” IEEE Trans.on Magn., Vol.45, no.3, pp.1044- 1047, 2009). The time derivative term was discretized using the backward difference method (Reference 4: OCZienkiewicz, The Finite Element Method, Fourth Edition, McGraw-Hill, 1994) in the time domain.

(B) Electromagnetic force calculation method The force distribution in the core required for static structural analysis and vibration analysis is the nodal force method (Reference 5: A. Kameari, “Local force calculation in 3D FEM with edge element,” Using the Maxwell stress tensor of International Journal of Applied Electromagnetics in Material, vol.3, pp.231-240, 1993) and Chu model, nodal force _fms ^(ip) due to electromagnetic force at nodal ^ip was obtained.

(C) Modeling of magnetostriction using nodal force The nodal force f _ms ^(ip) due to magnetostriction at each node ip of the finite element ie when the magnetic flux density B ^(ie) was applied was calculated. First, when magnetic flux density B is applied to the magnetic material, the respective magnetostrictions in the direction parallel to and perpendicular to B are denoted by ε _p and ε _v .

（αを定数、ｖをポアソン比とする）となる。
変位ｕは要素ｉｅの節点ｉｐ上で、次式により

(Α is a constant and v is a Poisson's ratio).
The displacement u is on the node ip of the element ie,

（Ｄ）静的構造解析
減衰項を無視した静的な構造解析の基礎方程式は

(D) Static structural analysis The basic equation of static structural analysis ignoring the attenuation term is

Where M is the mass matrix.
(E) Vibration analysis in frequency domain In the vibration analysis, force frequency components (see Document 2) f _em and f _ms are changed to F (ω) _em and F (ω) _ms by Fourier transform. At this time, the frequency component U (ω) of the displacement is obtained by the following equation.

ω is an angular frequency. The frequency domain transformation in the time domain is performed after calculating the equivalent nodal force. This is because the nonlinearity of the magnetic properties is taken into account in the force calculation.
(3. Model description and analysis conditions)
An analysis model is shown in FIG. The material constants of the normal reactor and the proposed improved single-phase reactor analysis model are shown in Table 1 below.

  Since it is symmetrical, only the 1/8 portion was analyzed. The core of the gap including the insulator is configured using AISI: M-19, a thickness of 0.35 mm, and the space factor F is 0.95. Two types of materials are used for the insulator, one being a soft material (for example, a meta-aramid material) and the other being a hard material (for example, an epoxy resin).

  The gap arrangement between the normal reactor and the proposed improved single-phase reactor is shown in FIGS. 9B and 9C. In the improved type, a gap is also added to the yoke portion, the overall length is the same as the normal one, and the inductance of the reactor is the same. The current in the coil of the reactor under power supply is shown in FIG. 10 in the time domain and the frequency domain. The basic frequency of the current is 60 Hz, and the carrier frequency is 2.5 kHz. The average magnetic flux density of the legs of both models is 0.6T.

  In the magnetic field analysis, the time interval Δt in the step-by-step method (time difference method) was 0.0597 ms, and only this period was calculated. In the static structure analysis and vibration analysis, only the iron core, push plate, and gap are analyzed. The laminated iron core is approximated by an isotropic massive iron core. The analysis region was divided into 4320 with one-dimensional rectangular parallelepiped elements. The iron core, push plate, and gap are assumed to be completely connected. The Dirichlet boundary condition u = 0 means the surface assembly position in FIG. This is because the surface is fixed by a hard plate.

(4. Optimization using static structural analysis)
In order to reduce reactor noise, the optimal hardness of the gap in the reactor is determined and a new model of the single phase reactor is designed using static structural analysis to save computation time.
FIG. 11 and FIG. 12 show displacement distributions by a normal single-phase reactor when a soft gap and a hard gap are respectively added at z = 0 on the xy plane in both electromagnetic force and magnetostriction. By selecting a hard insulator for the gap, the total displacement shown in FIG. 12C can be reduced by the influence of both electromagnetic force and magnetostriction compared to FIG. 11C. I understand that I can do it. The yoke part is displaced in the negative direction of the y-axis as shown in FIG. 12A by the attractive force due to the electromagnetic force between the yoke part and the leg part. At the same time, since the leg portion extends in the y direction due to the magnetostriction, FIG. 12B shows that the displacement of the yoke portion due to the magnetostriction along the y axis is positive contrary to the electromagnetic force. FIG. 12C shows that the displacement along the y-axis at the top of the yoke cancels each other due to the positive displacement. However, the displacement of the yoke portion along the x-axis remains large.

  In order to reduce the x-direction displacement on the side surface of the yoke part, a gap is added in the yoke part as shown in FIG. The improved displacement distribution using a hard gap is shown in FIG. Due to both electromagnetic force and magnetostriction along the x-axis, the displacement can also be canceled out as with the y-axis. Therefore, not only the displacement of the upper portion of the gap but also the side surface of the yoke portion can be removed by inserting a gap into the yoke portion and selecting a hard material for the gap.

(5. Vibration analysis of single-phase reactor)
In order to evaluate the effectiveness of the improved single-phase reactor, the results of vibration analysis were presented. FIG. 14 is a frequency spectrum of the y component F _sy of the total force of the electromagnetic force and the magnetostriction at the point s (see FIG. 9) where the force increases in the normal type and the improved type reactors. The amplitude is increased at 0 Hz, the amplitude at 120 Hz, which is twice the fundamental frequency, and the carrier frequency at 2.5 kHz. The same is true for the forces in both models.

  The frequency spectrum of the y component of the displacement at the point p (see FIG. 9) and the x component of the displacement at the point q (see FIG. 9) is expressed in μm and dB. These numerical values are obtained from vibration analysis in the frequency domain and are shown in FIGS. The displacement was converted to μm and dB using the following equation.

The displacement U ₀ is 1.1 × 10 ⁻¹¹ m and indicates the displacement of air at the audible limit.

  Vibration analysis shows that several resonances occur at different frequencies in both the normal and improved types. At points p and q, the improved noise level with a hard gap was also shown to be smaller in the wide frequency band than the normal type with a soft gap. As the vibration level, calculated values for the normal type and the improved type were obtained by using the A-weighting method (from IEC 61672). At point p, the vibration level was 38.3 dB for the normal type and 35.9 dB for the improved type. At point q, the normal type was 38.3 dB and the improved type was 37.5 dB. By using the improved type at two points, the noise level can be reduced.

(6. Investigation based on experiments)
(A) Measurement model and conditions Noise generated by a normal reactor using a soft gap, noise generated by a normal reactor using a hard gap, and an improved analysis of the same size and material as a normal type using a hard gap The model was measured experimentally. The magnetomotive force of the coil is 2.6 kAT. The coil current is a direct current generated by a chopper circuit and includes a high frequency component (6 kHz, 15%). The average magnetic flux density in the reactor leg is about 0.52T. FIG.

As shown in (B), noise measured from three different points 300 mm away from the reactor was measured with a sound level meter.
(B) Measurement results and discussion Table 2 shows a noise level measured by a normal A-weighting method using a soft gap and a hard gap, and an improved noise level using a hard gap.

  The noise level of the normal type reactor and the improved type reactor using the hard gap is smaller than the noise level of the normal type reactor using the soft gap. This agrees with the analysis result of the displacement of the yoke upper surface, and the noise is reduced by the hard gap. The improved version with a stiff gap also does not reduce noise compared to the normal side. This is because it is difficult to correct the yoke part of the core, and a gap exists between the insulator and the iron core in the gap in the yoke part. Therefore, the noise level was not affected. This can be solved by studying the manufacturing method of the gap in the yoke part.

(7. Conclusion)
By selecting a hard gap for the reactor and adding a gap in the yoke portion, noise due to displacement on the surface of the yoke portion can be reduced more than usual. The effect of the proposed new model was confirmed by vibration analysis and measurement in the frequency domain.

1 Electrical equipment 2 Iron core 3 Spacer

Claims (8)

In electrical equipment that is formed by interposing a spacer made of an elastic material in the middle part of an iron core that is inserted through an electromagnetic coil and extends in the direction of magnetic flux due to magnetostriction,
The electrical apparatus is characterized in that the spacer is arranged so that the amount of deformation of the spacer due to the electromagnetic force of the iron core matches the amount of magnetostriction of the iron core due to magnetic flux generated in the electromagnetic coil. . The electric device according to claim 1,
The electric device according to claim 1, wherein the spacer is disposed at a middle portion of the iron core leg portion and the yoke portion in a direction orthogonal to the magnetic flux generated by the electromagnetic coil. The electrical device according to claim 2,
The Young's modulus E _{1 of the} spacer disposed in the direction orthogonal to the magnetic flux is

(Where α is a constant (constant corresponding to the material of the iron core), L _{t is} the length of the central axis of the iron core (excluding the spacer), μ _{g is} the magnetic permeability of the spacer, and G _{t is} the thickness of the spacer. ) Is an electrical device. The electric device according to any one of claims 1 to 3,
The electric device, wherein the spacer is disposed on the leg portion and the yoke portion of the iron core in a direction parallel to the magnetic flux generated by the electromagnetic coil. The electric device according to claim 4,
The Young's modulus E _{2 of the} spacer disposed in the direction parallel to the magnetic flux is

(Where β is a constant (constant corresponding to the material of the iron core), L _{t is} the thickness of the iron core (excluding the spacer), μ _{g is} the magnetic permeability of the spacer, and G _{t is} the thickness of the spacer). Electrical equipment characterized by that. The electric device according to any one of claims 1 to 5,
The electric device according to claim 1, wherein the spacer includes a plurality of layers, and the thickness and / or material of each of the plurality of layers is different. The electric device according to any one of claims 1 to 6,
The electrical device is a three-phase transformer or a three-phase reactor,
The magnetic resistance of the spacer disposed on the leg portion in the V phase is a total value of the magnetic resistance of the spacer disposed on the leg portion in the U phase or the W phase and the yoke portion. machine. The electric device according to any one of claims 1 to 7,
An electric device comprising: a fixing tool that fixes the iron core in a leg direction, a yoke direction, and / or a thickness direction of the electric device.

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