JP2008125242A - Permanent magnet type synchronous electric motor - Google Patents

Permanent magnet type synchronous electric motor Download PDF

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Publication number
JP2008125242A
JP2008125242A JP2006306204A JP2006306204A JP2008125242A JP 2008125242 A JP2008125242 A JP 2008125242A JP 2006306204 A JP2006306204 A JP 2006306204A JP 2006306204 A JP2006306204 A JP 2006306204A JP 2008125242 A JP2008125242 A JP 2008125242A
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permanent magnet
conductor
synchronous motor
type synchronous
heat
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Takashi Okitsu
隆志 沖津
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Meidensha Corp
Meidensha Electric Manufacturing Co Ltd
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Meidensha Corp
Meidensha Electric Manufacturing Co Ltd
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly efficient and inexpensive permanent magnet-type synchronous electric motor where heat generation of a permanent magnet is suppressed and thermal demagnetization of the permanent magnet is prevented. <P>SOLUTION: The permanent magnet-type synchronous electric motor holding the permanent magnet 1 in a rotor core is provided with a conductor 2 which surrounds the permanent magnet 1 and reduces eddy current of the permanent magnet 1 and whose conductivity is higher than the that of permanent magnet 1. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

本発明は、永久磁石式同期電動機に関する。   The present invention relates to a permanent magnet type synchronous motor.

従来、永久磁石式同期電動機(PMモータ)の永久磁石20(図8参照)には、モータの高効率化や小型化を図るため、高性能なネオジウム・鉄・ボロン(NdFeB)等の希土類焼結磁石が採用されている。ネオジウム系の永久磁石20は、以前に用いられていたフェライト永久磁石等に比べ、温度変化に弱く、導電率がはるかに高いという性質がある。図8は永久磁石の渦電流を示した図である。図8に示すように、永久磁石20には、スロット高調波やインバータのキャリア高調波等による磁場変動Bによって渦電流Jが発生し、これによる渦電流損失が無視できなくなっている。永久磁石20の渦電流損失が大きくなると、永久磁石20の温度が高くなり、弱め界磁制御時等の永久磁石20に反磁界が加わる条件下では熱減磁を起こしやすくなる。そこで、ロータコア21に保持された永久磁石20を、図9(a)に示すように軸方向、又は、図9(b)に示すように周方向(回転方向)に分割して各永久磁石20間に絶縁層22を設けることにより、永久磁石20の渦電流損失を低減し減磁しにくくする方法や、温度変化に強い永久磁石20(例えば、サマリウム・コバルト(SmCo)系の磁石)を使用するなどの対策が採られている。このような技術の一例が下記特許文献1〜4に開示されている。なお、下記特許文献1には、永久磁石20を軸方向において複数に分割し、渦電流の発生を低減するものが開示されている。下記特許文献2には、永久磁石20を軸方向おいて2分割以上し、渦電流損失を低減するものが開示されている。下記特許文献3には、永久磁石20の幅をロータコア21の反回転方向に進むにつれて短くなるようにして、弱め界磁制御の際に発生する渦電流損失を低減するものが開示されている。下記特許文献4には、永久磁石20を円周方向に分割し、渦電流損失を低減するものが開示されている。   Conventionally, the permanent magnet 20 of a permanent magnet type synchronous motor (PM motor) (see FIG. 8) includes a rare earth sintered material such as high performance neodymium / iron / boron (NdFeB) in order to increase the efficiency and size of the motor. A magnet is used. The neodymium-based permanent magnet 20 has a property that it is weak against temperature change and has a much higher electrical conductivity than a ferrite permanent magnet or the like used previously. FIG. 8 shows the eddy current of the permanent magnet. As shown in FIG. 8, an eddy current J is generated in the permanent magnet 20 due to magnetic field fluctuations B due to slot harmonics, inverter carrier harmonics, etc., and eddy current loss due to this is no longer negligible. When the eddy current loss of the permanent magnet 20 increases, the temperature of the permanent magnet 20 increases, and thermal demagnetization is likely to occur under a condition in which a demagnetizing field is applied to the permanent magnet 20 such as during field-weakening control. Therefore, the permanent magnets 20 held by the rotor core 21 are divided in the axial direction as shown in FIG. 9A or in the circumferential direction (rotation direction) as shown in FIG. A method of reducing the eddy current loss of the permanent magnet 20 to make it difficult to demagnetize by providing an insulating layer 22 between them, and a permanent magnet 20 (for example, a samarium-cobalt (SmCo) magnet) that is resistant to temperature changes are used. Measures such as doing are taken. An example of such a technique is disclosed in the following Patent Documents 1 to 4. Patent Document 1 below discloses a permanent magnet 20 that is divided into a plurality of parts in the axial direction to reduce the generation of eddy currents. The following Patent Document 2 discloses a permanent magnet 20 that is divided into two or more in the axial direction to reduce eddy current loss. Patent Document 3 listed below discloses a technique for reducing the eddy current loss generated during field-weakening control by reducing the width of the permanent magnet 20 in the counter-rotating direction of the rotor core 21. Patent Document 4 listed below discloses a technique in which the permanent magnet 20 is divided in the circumferential direction to reduce eddy current loss.

特開2005−354899号公報JP 2005-354899 A 特開2005−204461号公報JP 2005-204461 A 特開2004−96868号公報JP 2004-96868 A 特開2000−228838号公報JP 2000-228838 A

しかしながら、図9に示すように、永久磁石20を軸方向又は周方向に分割する方法の場合、永久磁石20の分割数を多くすればするほど渦電流損失は減少し、熱減磁する危険性は少なくなるが、永久磁石20の分割数の増大に伴い永久磁石式同期電動機の製作に要する手間(時間)が増え、コストが増大してしまう。   However, as shown in FIG. 9, in the method of dividing the permanent magnet 20 in the axial direction or the circumferential direction, the eddy current loss decreases as the number of divisions of the permanent magnet 20 increases, and the risk of thermal demagnetization. However, as the number of divisions of the permanent magnet 20 increases, the labor (time) required for manufacturing the permanent magnet type synchronous motor increases, and the cost increases.

また、温度変化に弱いネオジウム系の永久磁石20ではなく、温度変化に強い永久磁石20(例えば、サマリウム・コバルト系の永久磁石)を使用する方法の場合、ネオジウム系の永久磁石20よりも性能が劣り(磁力が弱い)、高価であるため、永久磁石式同期電動機の高効率化や小型化、コストに関してある程度の妥協をしなくてはならない。   Also, in the case of using a permanent magnet 20 (for example, a samarium / cobalt permanent magnet) that is resistant to temperature changes, rather than the neodymium permanent magnet 20 that is vulnerable to temperature changes, the performance is higher than that of the neodymium permanent magnet 20. Because it is inferior (weak magnetic force) and expensive, there must be some compromise on the efficiency, miniaturization, and cost of the permanent magnet synchronous motor.

以上のことから、本発明は、永久磁石20の発熱を抑えて永久磁石20の熱減磁を防ぎ、さらに高効率で低コストな永久磁石式同期電動機を提供することを目的とする。   In view of the above, an object of the present invention is to provide a permanent magnet type synchronous motor that suppresses heat generation of the permanent magnet 20 to prevent thermal demagnetization of the permanent magnet 20 and is highly efficient and low in cost.

上記の課題を解決するための第1の発明(請求項1に対応)に係る永久磁石式同期電動機は、
ロータコアにより永久磁石を保持する永久磁石式同期電動機において、
前記永久磁石を囲んで前記永久磁石の渦電流を減少させる前記永久磁石よりも導電率の高い導体を備える
ことを特徴とする永久磁石式同期電動機。
A permanent magnet synchronous motor according to a first invention (corresponding to claim 1) for solving the above-described problems is
In a permanent magnet type synchronous motor that holds a permanent magnet by a rotor core,
A permanent magnet type synchronous motor comprising a conductor having higher conductivity than the permanent magnet which surrounds the permanent magnet and reduces eddy current of the permanent magnet.

上記の課題を解決するための第2の発明(請求項2に対応)に係る永久磁石式同期電動機は、第1の発明に係る永久磁石式同期電動機において、前記導体の表面を覆うことで該導体の熱が前記永久磁石や前記ロータコアに伝わることを防ぐ断熱材を備えることを特徴とする。   A permanent magnet synchronous motor according to a second invention (corresponding to claim 2) for solving the above-mentioned problem is the permanent magnet synchronous motor according to the first invention, wherein the permanent magnet synchronous motor covers the surface of the conductor. A heat insulating material for preventing the heat of the conductor from being transmitted to the permanent magnet and the rotor core is provided.

上記の課題を解決するための第3の発明(請求項3に対応)に係る永久磁石式同期電動機は、第2の発明に係る永久磁石式同期電動機において、前記断熱材は、前記導体の熱を外部に放出し該導体の温度上昇を抑制すべく前記ロータコア端部の前記導体端部表面には設置しないことを特徴とする。   A permanent magnet synchronous motor according to a third invention (corresponding to claim 3) for solving the above problem is the permanent magnet synchronous motor according to the second invention, wherein the heat insulating material is a heat of the conductor. Is not installed on the surface of the conductor end of the rotor core end so as to suppress the temperature rise of the conductor.

上記の課題を解決するための第4の発明(請求項4に対応)に係る永久磁石式同期電動機は、第1の発明に係る永久磁石式同期電動機において、前記導体は、導線で形成することを特徴とする。   A permanent magnet synchronous motor according to a fourth invention (corresponding to claim 4) for solving the above problems is the permanent magnet synchronous motor according to the first invention, wherein the conductor is formed of a conductive wire. It is characterized by.

上記の課題を解決するための第5の発明(請求項5に対応)に係る永久磁石式同期電動機は、第1の発明に係る永久磁石式同期電動機において、前記導体は、前記永久磁石及び前記ロータコアよりも熱伝導率が高く、前記導体端部表面での放熱量が該導体の発熱量より大きいことを特徴とする。   A permanent magnet synchronous motor according to a fifth invention (corresponding to claim 5) for solving the above problems is the permanent magnet synchronous motor according to the first invention, wherein the conductor is the permanent magnet and the permanent magnet The heat conductivity is higher than that of the rotor core, and the heat radiation amount on the surface of the conductor end is larger than the heat generation amount of the conductor.

本願発明によれば、永久磁石式同期電動機の永久磁石を導体で囲むことにより、永久磁石の渦電流損失を大幅に減少させることができる。また、渦電流損失減少により、永久磁石の発熱量が小さくなり、永久磁石(永久磁石式同期電動機)の性能の低下及び熱減磁を防止することができる。   According to the present invention, the eddy current loss of the permanent magnet can be greatly reduced by surrounding the permanent magnet of the permanent magnet type synchronous motor with the conductor. Further, due to the decrease in eddy current loss, the amount of heat generated by the permanent magnet is reduced, and the performance of the permanent magnet (permanent magnet type synchronous motor) can be prevented from being degraded and thermal demagnetization can be prevented.

本発明に係る永久磁石式同期電動機の実施形態について、図1〜図7を用いて説明する。図1は第1の実施形態に係る導体の斜視図、図2は第2の実施形態に係る断熱材の斜視図、図3は第3の実施形態に係る導線で形成した導体の斜視図、図4は第4の実施形態に係る導体の斜視図、図5は本発明に係る永久磁石式同期電動機の平面図、図6は図5中のA点の時間変化における磁束密度を示した図、図7は永久磁石の周囲を導体で囲んだ導体あり場合と、導体で囲んでいない導体なし場合の磁石渦電流損失を示した図である。   An embodiment of a permanent magnet type synchronous motor according to the present invention will be described with reference to FIGS. FIG. 1 is a perspective view of a conductor according to the first embodiment, FIG. 2 is a perspective view of a heat insulating material according to the second embodiment, and FIG. 3 is a perspective view of a conductor formed by a conductive wire according to the third embodiment. FIG. 4 is a perspective view of a conductor according to the fourth embodiment, FIG. 5 is a plan view of a permanent magnet type synchronous motor according to the present invention, and FIG. 6 is a diagram showing magnetic flux density over time at point A in FIG. FIG. 7 is a diagram showing magnet eddy current loss when there is a conductor surrounded by a conductor around a permanent magnet and when there is no conductor not surrounded by a conductor.

[第1の実施形態]
始めに、本発明に係る永久磁石式同期電動機について説明する。図5に示すように、本発明に係る永久磁石式同期電動機は、12極18スロットの集中巻き機であり、ロータコア6内部に永久磁石1を埋め込んだIPM(Interior Permanent Magnetic)構造となっている。永久磁石1の側方には、永久磁石1の磁束の短絡を防止するため空間であるフラックスバリア7が形成されている。ロータコア6の周方向外側には、ロータコア6と対向するようにステータコア8が設置されており、ステータコア8の内部には巻線9が配置されている。なお、図5では、ロータコア6及びステータコア8共に一部についてのみ示しているが、実際にはロータコア6及びステータコア8は円筒状になるよう形成されている。また、本実施形態では、ロータコア6内部に永久磁石1を埋め込んで永久磁石1を保持する構造としたが、このような構造以外にも、例えばロータコア6の表面などに永久磁石1を設置する構造とすることも可能である。
[First Embodiment]
First, a permanent magnet type synchronous motor according to the present invention will be described. As shown in FIG. 5, the permanent magnet type synchronous motor according to the present invention is a 12-pole 18-slot concentrated winding machine, and has an IPM (Interior Permanent Magnetic) structure in which the permanent magnet 1 is embedded in the rotor core 6. . On the side of the permanent magnet 1, a flux barrier 7, which is a space, is formed to prevent a short circuit of the magnetic flux of the permanent magnet 1. A stator core 8 is disposed on the outer side in the circumferential direction of the rotor core 6 so as to face the rotor core 6, and a winding 9 is disposed inside the stator core 8. In FIG. 5, only a part of the rotor core 6 and the stator core 8 is shown, but the rotor core 6 and the stator core 8 are actually formed in a cylindrical shape. In the present embodiment, the permanent magnet 1 is embedded in the rotor core 6 to hold the permanent magnet 1. However, in addition to such a structure, for example, a structure in which the permanent magnet 1 is installed on the surface of the rotor core 6. It is also possible.

永久磁石式同期電動機を駆動した場合、永久磁石1には巻線9の巻溝であるスロットに起因する磁場変動が生じて、その磁場変動を打ち消すように渦電流が流れるため渦電流損失となり、この渦電流損失が熱となって永久磁石1の温度が上昇する。図5中A点で示す位置の磁束密度の時間変化を図6に示す。図6に示すように、A点では、電流の1周期に対して、スロットによる3倍の周期の磁場変動が永久磁石1に生じていることが分かる。渦電流損失により永久磁石1の温度が上昇すると、永久磁石1の残留磁束密度や保持力が減少するため、永久磁石1の性能が悪化し、永久磁石式同期電動機の効率悪化に繋がる。また、永久磁石式同期電動機の弱め界磁制御駆動時には、永久磁石1の磁化方向と逆向きの磁界が永久磁石1に加わるため、発熱により保持力が減少し、その保持力を上回る磁界が永久磁石1に加わると最悪の場合には永久磁石1が減磁することとなる。   When the permanent magnet type synchronous motor is driven, a magnetic field fluctuation caused by the slot that is the winding groove of the winding 9 occurs in the permanent magnet 1, and an eddy current flows so as to cancel the magnetic field fluctuation, resulting in an eddy current loss. This eddy current loss becomes heat and the temperature of the permanent magnet 1 rises. FIG. 6 shows the time change of the magnetic flux density at the position indicated by point A in FIG. As shown in FIG. 6, at point A, it can be seen that the magnetic field fluctuation of the period three times as long as the slot occurs in the permanent magnet 1 with respect to one period of the current. When the temperature of the permanent magnet 1 rises due to eddy current loss, the residual magnetic flux density and the holding force of the permanent magnet 1 are reduced, so that the performance of the permanent magnet 1 is deteriorated and the efficiency of the permanent magnet synchronous motor is deteriorated. Further, when the field-weakening control driving of the permanent magnet type synchronous motor is performed, a magnetic field opposite to the magnetization direction of the permanent magnet 1 is applied to the permanent magnet 1. In the worst case, the permanent magnet 1 is demagnetized.

次に、本実施形態に係る永久磁石式同期電動機の要部の構成について説明する。図1に示すように、永久磁石1の周囲を永久磁石1よりも導電率の高い導体2(例えば、アルミニウム製の薄板3)で囲むことにより、永久磁石1の磁場変動を小さくし、渦電流損失による発熱を低減する。なお、導体2にはアルミニウムの他にも銅などを用いることもできる。   Next, the structure of the principal part of the permanent magnet type synchronous motor according to the present embodiment will be described. As shown in FIG. 1, by surrounding the permanent magnet 1 with a conductor 2 (for example, an aluminum thin plate 3) having a higher conductivity than the permanent magnet 1, magnetic field fluctuations of the permanent magnet 1 are reduced, and eddy currents are reduced. Reduce heat generation due to loss. For the conductor 2, copper or the like can be used in addition to aluminum.

ここで、有限要素法による磁界解析で算出した永久磁石1の周囲を導体2で囲んだ導体2ありの場合と、導体2で囲んでいない導体2なし場合の磁石渦電流損失の比較を図7に示す。なお、ここでは渦電流損失の値は導体2なしの場合の磁石渦電流損失を1として正規化している。図7から、永久磁石1の周囲を導体2で囲んだ場合、導体2なしの場合に比べ永久磁石1の渦電流損失が約1/10に低減することが分かる。   Here, a comparison of the magnet eddy current loss in the case of the conductor 2 surrounded by the conductor 2 and the case of the conductor 2 not surrounded by the conductor 2 calculated by the magnetic field analysis by the finite element method is shown in FIG. Shown in Here, the value of the eddy current loss is normalized assuming that the eddy current loss of the magnet without the conductor 2 is 1. From FIG. 7, it can be seen that when the periphery of the permanent magnet 1 is surrounded by the conductor 2, the eddy current loss of the permanent magnet 1 is reduced to about 1/10 compared to the case without the conductor 2.

このように、本実施形態に係る永久磁石式同期電動機によれば、永久磁石式同期電動機の永久磁石1を導体2で囲むことにより、永久磁石1の渦電流損失を大幅に減少させることができる。また、渦電流損失減少により、永久磁石1の発熱量が小さくなり、永久磁石1(永久磁石式同期電動機)の性能の低下及び熱減磁を防止することができる。   Thus, according to the permanent magnet type synchronous motor according to the present embodiment, the eddy current loss of the permanent magnet 1 can be greatly reduced by surrounding the permanent magnet 1 of the permanent magnet type synchronous motor with the conductor 2. . Further, due to the decrease in eddy current loss, the amount of heat generated by the permanent magnet 1 is reduced, and the performance of the permanent magnet 1 (permanent magnet synchronous motor) can be prevented from being deteriorated and thermal demagnetization can be prevented.

[第2の実施形態]
本実施形態に係る永久磁石式同期電動機の要部の構成について説明する。図7に示すように、第1の実施形態では、永久磁石1における渦電流損失が小さくなる代わりに、導体2における渦電流損失が発生してしまうため、導体2の熱が永久磁石1に伝わり、永久磁石1が加熱される虞がある。
[Second Embodiment]
A configuration of a main part of the permanent magnet type synchronous motor according to the present embodiment will be described. As shown in FIG. 7, in the first embodiment, instead of reducing the eddy current loss in the permanent magnet 1, eddy current loss in the conductor 2 occurs, so that the heat of the conductor 2 is transmitted to the permanent magnet 1. The permanent magnet 1 may be heated.

このため、本実施形態では、図2に示すように、導体2の表面を熱伝導率の小さい断熱材4等で覆うこととした。その際、永久磁石式同期電動機端部に位置する導体2が空気に触れる導体2の端部面2aには断熱材4を設置せず導体2を剥き出しにし、熱を外部に放出することにより、導体2の温度上昇を小さくすることができる。   For this reason, in this embodiment, as shown in FIG. 2, the surface of the conductor 2 was covered with a heat insulating material 4 having a low thermal conductivity. At that time, the conductor 2 located at the end of the permanent magnet type synchronous motor is exposed to the air, and the end face 2a of the conductor 2 is not provided with the heat insulating material 4, but the conductor 2 is exposed, and heat is released to the outside, The temperature rise of the conductor 2 can be reduced.

ここで、断熱材4とは、熱を伝えにくい材料のことで、熱伝導率λがλ=0.06W/mK(0.05kcal/mh℃)以下の材料のことを意味する。断熱材4の例としては、発砲プラスチック系断熱材として、押出法ポリスチレンフォーム、ビーズ法ポリスチレンフォーム、硬質ポリウレタンフォーム、ポリエチレンフォーム、ポリプロピレンフォーム、イソシアヌレートフォーム、フェノールフォームがあり、無機繊維系断熱材として、グラスウール、ロックウールがある。   Here, the heat insulating material 4 is a material that hardly transmits heat, and means a material having a thermal conductivity λ of λ = 0.06 W / mK (0.05 kcal / mh ° C.) or less. Examples of the heat insulating material 4 include an extruded polystyrene foam, a bead polystyrene foam, a rigid polyurethane foam, a polyethylene foam, a polypropylene foam, an isocyanurate foam, a phenol foam, and an inorganic fiber heat insulating material. , Glass wool, rock wool.

このように、本実施形態に係る永久磁石式同期電動機によれば、導体2の表面を熱伝導率の小さい断熱材4などで覆うことにより、導体2で発熱する熱を永久磁石1に伝えにくくすることができる。また、永久磁石式同期電動機端部の導体2が空気に触れる導体2の端部面2aには断熱材4を設置せず、導体2を剥き出しにすることにより、導体2の熱を外部に放出し、導体2の温度上昇を抑えることができる。   As described above, according to the permanent magnet type synchronous motor according to the present embodiment, it is difficult to transfer heat generated by the conductor 2 to the permanent magnet 1 by covering the surface of the conductor 2 with the heat insulating material 4 having a low thermal conductivity. can do. In addition, the conductor 2 at the end of the permanent magnet type synchronous motor is exposed to the air. The heat insulating material 4 is not provided on the end surface 2a of the conductor 2 and the conductor 2 is exposed to release the heat of the conductor 2 to the outside. And the temperature rise of the conductor 2 can be suppressed.

[第3の実施形態]
本実施形態に係る永久磁石式同期電動機の要部の構成について説明する。図5に示すように、通常、IPM構造の永久磁石式同期電動機の永久磁石1の側方には、永久磁石1の磁束の短絡を防止するためフラックスバリア7と呼ばれる溝が形成されている。第1の実施形態に係る導体2として例示したアルミニウム製の薄板3(図1参照)の場合、アルミニウム製の薄板3は硬いため、ロータコア6に永久磁石1を挿入する段階でアルミニウム製の薄板3も一緒に挿入するか、もしくは、薄板3をコ字状にして永久磁石1の挿入後に薄板3と同材質の板状導体で蓋をしなければならず、ロータコア6へ永久磁石1を固定する作業の効率が低くなってしまう。
[Third Embodiment]
A configuration of a main part of the permanent magnet type synchronous motor according to the present embodiment will be described. As shown in FIG. 5, a groove called a flux barrier 7 is usually formed on the side of the permanent magnet 1 of the permanent magnet type synchronous motor having an IPM structure in order to prevent a short circuit of the magnetic flux of the permanent magnet 1. In the case of the aluminum thin plate 3 (see FIG. 1) exemplified as the conductor 2 according to the first embodiment, the aluminum thin plate 3 is hard, and therefore the aluminum thin plate 3 is inserted at the stage of inserting the permanent magnet 1 into the rotor core 6. Must be inserted together, or the thin plate 3 should be U-shaped and the permanent magnet 1 must be inserted and then covered with a plate-like conductor made of the same material as the thin plate 3 to fix the permanent magnet 1 to the rotor core 6. Work efficiency will be reduced.

このため、本実施形態では、図3に示すように、導体2に薄板3ではなく導線5を使用することで、永久磁石1挿入後に導線5をフラックスバリア7に通して永久磁石1を囲い導体2を短絡させることにより、第1の実施形態と同様の効果を得ることができる。また、この方法を用いれば、既存の永久磁石式同期電動機にも第1の実施形態を適用することが可能である。   For this reason, in this embodiment, as shown in FIG. 3, by using the conductor 5 instead of the thin plate 3 for the conductor 2, the conductor 5 is passed through the flux barrier 7 after the permanent magnet 1 is inserted to surround the permanent magnet 1. By short-circuiting 2, the same effect as in the first embodiment can be obtained. If this method is used, the first embodiment can be applied to an existing permanent magnet type synchronous motor.

このように、本実施形態に係る永久磁石式同期電動機によれば、IPM構造の永久磁石式同期電動機の場合、永久磁石1を囲む導体2に導線5を用いることで、フラックスバリア7に導線5を通して永久磁石1を囲んで導体2を短絡させることにより、既存の永久磁石式同期電動機にも第1の実施形態を適用することが可能である。   As described above, according to the permanent magnet type synchronous motor according to the present embodiment, in the case of the permanent magnet type synchronous motor having the IPM structure, the lead wire 5 is used for the flux barrier 7 by using the lead wire 5 for the conductor 2 surrounding the permanent magnet 1. The first embodiment can be applied to an existing permanent magnet type synchronous motor by surrounding the permanent magnet 1 and short-circuiting the conductor 2.

[第4の実施形態]
本実施形態に係る永久磁石式同期電動機の要部の構成について説明する。本実施形態では、図4に示すように、断熱材4を用いずに、永久磁石1を囲む導体2に熱伝導率の高い材料を用いることにより、永久磁石1で発生する熱と導体2で発生する熱を導体2の端部面2aから図4中に矢印で示すように外部へ放出する。ここで、熱伝導率の高い材料として、例えば、純アルミニウムAl(A1100):222W/(m・K)や純銅Cu(C1100):384W/(m・K)などがある。なお、本実施形態では、永久磁石1及び導体2を磁石オサエ板10でロータコア6に固定する構造を適用することもできる。
[Fourth Embodiment]
A configuration of a main part of the permanent magnet type synchronous motor according to the present embodiment will be described. In the present embodiment, as shown in FIG. 4, by using a material having high thermal conductivity for the conductor 2 surrounding the permanent magnet 1 without using the heat insulating material 4, the heat generated in the permanent magnet 1 and the conductor 2 are used. The generated heat is released from the end surface 2a of the conductor 2 to the outside as indicated by an arrow in FIG. Here, examples of the material having high thermal conductivity include pure aluminum Al (A1100): 222 W / (m · K) and pure copper Cu (C1100): 384 W / (m · K). In addition, in this embodiment, the structure which fixes the permanent magnet 1 and the conductor 2 to the rotor core 6 with the magnet spring board 10 is also applicable.

また、導体2の端部面2aからの放熱量が小さく導体2の発熱量が大きい場合は、導体2の熱が永久磁石1に伝わり永久磁石1が熱減磁する虞があるため、導体2の発熱量よりも導体2の端部面2aでの放熱量の方が大きくなるよう設計する。   In addition, when the amount of heat released from the end surface 2a of the conductor 2 is small and the amount of heat generated by the conductor 2 is large, the heat of the conductor 2 is transmitted to the permanent magnet 1 and the permanent magnet 1 may be thermally demagnetized. The heat radiation amount at the end surface 2a of the conductor 2 is designed to be larger than the heat generation amount.

すなわち、永久磁石1よりも導電率の高い導体2を永久磁石1の周囲に固定することで永久磁石1の磁場変動を減らして永久磁石1の発熱を減らすと共に、永久磁石1を囲む導体2に熱伝導率の高い材料(永久磁石1、ロータコア6、磁石オサエ板10に比べて熱伝導率が高い材料)を用いる。さらに、導電率が高く、且つ、熱伝導率が高い導体2の端部面2aの方熱量が大きくなる設計の例として、導体2の端部面2aにフィン構造を設けるなどして放熱面積を増やすことが挙げられる。   That is, by fixing the conductor 2 having higher conductivity than the permanent magnet 1 around the permanent magnet 1, the magnetic field fluctuation of the permanent magnet 1 is reduced to reduce the heat generation of the permanent magnet 1 and to the conductor 2 surrounding the permanent magnet 1. A material having a high thermal conductivity (a material having a higher thermal conductivity than the permanent magnet 1, the rotor core 6, and the magnet plate 10) is used. Furthermore, as an example of a design in which the end surface 2a of the conductor 2 having high conductivity and high thermal conductivity is increased, the heat radiation area is reduced by providing a fin structure on the end surface 2a of the conductor 2. Increase it.

このように、本実施形態に係る永久磁石式同期電動機によれば、永久磁石1よりも導電率の高い導体2を永久磁石1の周囲に固定することで永久磁石1の磁場変動を減らして永久磁石1の発熱を減らすと共に、永久磁石1を囲む導体2を熱伝導率の高い材料とすることにより、永久磁石1で発生する熱と導体2で発生する熱を導体2の端部面2aから外部へ放出することができる。   As described above, according to the permanent magnet type synchronous motor according to this embodiment, the conductor 2 having higher conductivity than the permanent magnet 1 is fixed around the permanent magnet 1 to reduce the magnetic field fluctuation of the permanent magnet 1 and become permanent. The heat generated by the permanent magnet 1 and the heat generated by the conductor 2 are reduced from the end surface 2a of the conductor 2 by reducing the heat generation of the magnet 1 and by making the conductor 2 surrounding the permanent magnet 1 a material having high thermal conductivity. Can be released to the outside.

第1の実施形態に係る導体の斜視図である。It is a perspective view of the conductor which concerns on 1st Embodiment. 第2の実施形態に係る断熱材の斜視図である。It is a perspective view of the heat insulating material which concerns on 2nd Embodiment. 第3の実施形態に係る導線で形成した導体の斜視図である。It is a perspective view of the conductor formed with the conducting wire which concerns on 3rd Embodiment. 第4の実施形態に係る導体の斜視図である。It is a perspective view of the conductor which concerns on 4th Embodiment. 本発明に係る永久磁石式同期電動機の平面図である。1 is a plan view of a permanent magnet type synchronous motor according to the present invention. 図5中のA点の時間変化における磁束密度を示した図である。It is the figure which showed the magnetic flux density in the time change of A point in FIG. 永久磁石の周囲を導体で囲んだ場合と、導体で囲んでいない場合の磁石渦電流損失を示した図である。It is the figure which showed the magnet eddy current loss when the circumference | surroundings of a permanent magnet are enclosed with a conductor, and when not enclosing with a conductor. 永久磁石の渦電流を示した図である。It is the figure which showed the eddy current of the permanent magnet. 従来の永久磁石式同期電動機の透視斜視図である。It is a perspective view of the conventional permanent magnet type synchronous motor.

符号の説明Explanation of symbols

1 永久磁石
2 導体
3 薄板
4 断熱材
5 導線
6 ロータコア
7 フラックスバリア
8 ステータコア
9 巻線
10 磁石オサエ板
DESCRIPTION OF SYMBOLS 1 Permanent magnet 2 Conductor 3 Thin plate 4 Heat insulating material 5 Conductor 6 Rotor core 7 Flux barrier 8 Stator core 9 Winding 10 Magnet plate

Claims (5)

ロータコアにより永久磁石を保持する永久磁石式同期電動機において、
前記永久磁石を囲んで前記永久磁石の渦電流を減少させる前記永久磁石よりも導電率の高い導体を備える
ことを特徴とする永久磁石式同期電動機。
In a permanent magnet type synchronous motor that holds a permanent magnet by a rotor core,
A permanent magnet type synchronous motor comprising a conductor having higher conductivity than the permanent magnet which surrounds the permanent magnet and reduces eddy current of the permanent magnet.
前記導体の表面を覆うことで該導体の熱が前記永久磁石や前記ロータコアに伝わることを防ぐ断熱材を備える
ことを特徴とする請求項1に記載の永久磁石式同期電動機。
The permanent magnet synchronous motor according to claim 1, further comprising a heat insulating material that covers a surface of the conductor to prevent heat of the conductor from being transmitted to the permanent magnet and the rotor core.
前記断熱材は、前記導体の熱を外部に放出し該導体の温度上昇を抑制すべく前記ロータコア端部の前記導体端部表面には設置しない
ことを特徴とする請求項2に記載の永久磁石式同期電動機。
3. The permanent magnet according to claim 2, wherein the heat insulating material is not installed on a surface of the conductor end portion of the rotor core end portion so as to release heat of the conductor to the outside and suppress a temperature rise of the conductor. Type synchronous motor.
前記導体は、導線で形成する
ことを特徴とする請求項1に記載の永久磁石式同期電動機。
The permanent magnet type synchronous motor according to claim 1, wherein the conductor is formed of a conductive wire.
前記導体は、前記永久磁石及び前記ロータコアよりも熱伝導率が高く、前記導体端部表面での放熱量が該導体の発熱量より大きい
ことを特徴とする請求項1に記載の永久磁石式同期電動機。
2. The permanent magnet synchronization according to claim 1, wherein the conductor has higher thermal conductivity than the permanent magnet and the rotor core, and a heat dissipation amount on the surface of the conductor end is larger than a heat generation amount of the conductor. Electric motor.
JP2006306204A 2006-11-13 2006-11-13 Permanent magnet type synchronous electric motor Withdrawn JP2008125242A (en)

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US8922084B2 (en) 2009-06-23 2014-12-30 Mitsui High-Tech, Inc. Rotor core
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JP2012178902A (en) * 2011-02-25 2012-09-13 Hitachi Industrial Equipment Systems Co Ltd Permanent magnet type rotary machine
JP2013176259A (en) * 2012-02-27 2013-09-05 Nissan Motor Co Ltd Permanent magnet dynamoelectric machine
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EP2645534A1 (en) * 2012-03-26 2013-10-02 Siemens Aktiengesellschaft Magnet component with a thermal insulation structure, rotor assembly with such a magnet component, electromechanical transducer and wind turbine
US9490672B2 (en) 2012-03-26 2016-11-08 Siemens Aktiengesellschaft Magnet component with a thermal insulation structure, rotor assembly with such a magnet component, electromechanical transducer and wind turbine
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