JP2002369473A - Synchronous motor using permanent magnet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a synchronous motor, having high efficiency and high power factor. SOLUTION: The synchronous motor is provided with a stator generating a rotating magnetic field, and a rotor which is rotated inside the stator by a shaft while applying electromagnetic action to the stator; in the stator, a multiphase winding 2 is wound around an amorphous core 1 where amorphous steel plates having large permeability are laminated in a ring type and wound; and the rotor includes two or three or four permanent magnets 41-44 which surround the stator.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synchronous motor using a permanent magnet for a rotor, and more particularly to an improvement in a stator thereof.

[0002]

2. Description of the Related Art Synchronous motors using permanent magnets for rotors (permanent magnet synchronous motors) are driven by a power inverter, are easy to drive, have excellent environmental resistance, are highly efficient, and have high power. Rate operation is possible. Also, because of its easy maintenance, it has attracted attention as a motor for industrial equipment and consumer equipment, and is widely used. Synchronous motors using permanent magnets are classified into two types according to the structure of the rotor. The former has a surface magnet structure and the latter has an embedded magnet structure, but the latter has attracted attention from the viewpoint of performance. That is, a PM (permanent magnet) motor (IPM) having an embedded magnet structure in which a permanent magnet is embedded inside the rotor can easily support the permanent magnet, and depending on the design, effectively uses reluctance torque in addition to magnet torque. You can also. By giving the optimum advance angle to the current vector during driving, even when the values of the driving voltage and the load current are restricted by the inverter specification or the like, the range in which the driving state is restricted is small and the application is wide.
Therefore, a highly efficient motor that meets the needs of the user can be designed for the PM motor having the embedded magnet structure.

In the PM motor, it is important to increase the motor torque by increasing the magnetic flux of the magnet, increasing the saliency, and increasing the inductance. The PM motor with the surface magnet structure has a saliency of almost 1 and no reluctance torque is generated.However, the PM motor with the embedded magnet structure uses a neodymium magnet to increase the magnetic flux of the magnet while reducing the magnet thickness. By deeply burying the magnet inside the motor, the inductance and the salient pole coefficient can be increased. Further, in order to increase the efficiency of the IPM motor while keeping the specification range of the rotation speed and the load torque wide, it is effective to increase the number of turns of the motor winding and increase the inductance.

On the other hand, a laminated core has been conventionally used for a stator. Since the laminated core has a high electric resistance, the eddy current is small, and the gap between the stator and the rotor is usually designed to be narrow to 1 mm. Since the stator is slotted and the magnetic field working space is limited inside the stator, the number of permanent magnets is limited to one. In addition, since the permeability of the core is relatively low, the number of turns of the winding is increased in order to increase the inductance. When the efficiency decreases, the capacity of the electric inverter needs to be increased, so that the size and weight of the circuit increase, and the economic efficiency decreases. In addition, electromagnetic interference (EMI) is generated around the core due to a leakage magnetic field, which affects peripheral electronic devices. Further, when the number of turns of the winding is increased, the copper loss due to the resistance of the copper wire increases. Therefore, it is advisable to increase the magnetic permeability μ of the core to increase the inductance and to reduce the leakage magnetic flux. On the other hand, P
When driving the M motor at a high frequency from the electric inverter, the increase in capacitance due to the winding cannot be ignored. Therefore, from this viewpoint, it is advisable to increase the magnetic permeability of the core.

[0005]

In a synchronous motor having an embedded magnet structure, the efficiency can be increased by increasing the inductance. Therefore, the inductance is increased by increasing the number of turns of the motor winding. Increasing the number of turns of the winding increases the inductance, but increases the leakage magnetic flux, further increases the copper loss and the capacitance. Therefore, it is not preferable to increase the number of turns of the winding from the viewpoint of EMI, efficiency, heat generation, and the like. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a synchro using a permanent magnet configured to increase the inductance of a core winding without increasing EMI, leakage flux, copper loss, and capacitance. It is to provide an eggplant motor.

[0006]

According to the present invention, there is provided a synchronous motor using a permanent magnet according to the present invention, comprising a stator in which a multi-phase winding is annularly wound around a core obtained by winding a steel plate in a ring shape and laminated, and two stators. The stator includes three or four permanent magnets, surrounds the stator, and has a rotor that rotates inside the stator while exerting an electromagnetic action on the stator.

[0007] In the synchronous motor using the permanent magnet, the core obtained by winding the above-mentioned steel sheet in a ring shape and laminating the core is formed by laminating an amorphous steel sheet over the whole, or by laminating an amorphous steel sheet on the outside and forming an electromagnetic steel sheet on the inside. Are laminated to form a sandwich structure.

In the synchronous motor using the permanent magnet according to the present invention, the ring-shaped core of the stator is formed by laminating the above-mentioned steel plate by winding the above steel sheet in a tape shape plural times in the circumferential direction of the core, or by setting the width direction of the core to the stator. They are arranged in the radial direction, wound around a plurality of times, and laminated.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. A feature of the present invention is that an amorphous core is used for a stator of a synchronous motor. Amorphous cores have high magnetic permeability but are inferior in workability. Therefore, they have been used in transformers, but not in rotating equipment. In the present invention, the arrangement of the stator and the rotor is devised so that the amorphous core can be used for rotating equipment. FIG. 1 is an explanatory diagram showing one embodiment of a stator of a synchronous motor using a permanent magnet according to the present invention, together with elements used for a rotor. In FIG. 1, 1 is an amorphous core, and 2 is a winding. 3 is a shaft, 41 to 4
Numeral 4 denotes a permanent magnet, which is an element constituting a rotor.

The amorphous core 1 is formed by laminating an amorphous steel sheet having a width D and a sufficiently long longitudinal direction in a tape shape plural times in a circumferential direction of the core. Since the amorphous steel sheet has a large magnetic permeability, a large inductance can be obtained without excessively increasing the number of windings of the winding, and high-frequency operation is possible. A winding 2 is wound around an amorphous core 1 formed by lamination. The winding 2 generates a rotating magnetic field in the core by sequentially applying a multi-phase AC voltage. For example, in a three-phase winding, W, -V, U, -W,
The winding is wound so that a three-phase voltage is applied in the order of V and -U. In such a winding, a six-phase AC voltage having a phase shifted by π / 3 is applied to each winding to obtain a rotating magnetic field. Although FIG. 1 shows an example in which the six windings are wound in the range of 120 degrees of the stator, actually, the angle is set to a smaller angle {(120 / N) degrees: N integer}.

As shown in FIG. 1, in the stator in which the winding 2 is wound around the amorphous core 1, the magnetic flux that gives the rotating magnetic field is extremely large because the magnetic permeability of the amorphous core 1 itself is large. Leakage magnetic flux can be suppressed extremely small. The rotor is inserted inside the stator thus configured, and the rotor is rotated by the action of the rotating magnetic field due to the alternating current flowing through the winding 2. FIG.
FIG. 3 is an explanatory view showing rotors of various configurations using three permanent magnets. FIGS. 2A to 2D are diagrams illustrating a rotor on which three permanent magnets PM are mounted. However, a configuration using two or four permanent magnets may be used. 2A to 2D, reference numerals 3a to 3d denote rotor shafts, 41a to 43a, and 41b, respectively.
-43b, 41c-43c, 41d-43d are the permanent magnets of the rotor shown in (a)-(d), respectively, 5a-5d
Are the permanent magnet supports of the rotor shown in (a) to (d), 6a to 6d are the amorphous cores of the stator shown in (a) to (d), respectively, and 7a to 7d are in (a) to (d), respectively. 2 is an amorphous core support for the indicated stator. It is assumed that the shafts 3a to 3d are each rotating at an angular velocity ω.

In the synchronous motor shown in FIGS. 1 and 2, since the amorphous core 1 is used for the stator, the magnetic flux is confined inside the amorphous core 1,
Almost no magnetic flux leakage occurs. In addition, FIG.
In each case (d), three permanent magnets 4 are attached to the rotor.
1a to 43a, 41b to 43b, 41c to 43c, 41
Since d to 43d are used, the magnetic flux of the permanent magnet is effectively transmitted to the stator to contribute to rotation. Therefore, 1
It is superior in that more magnetic flux is effectively used as compared with a conventional rotor using a plurality of permanent magnets. Furthermore, since the electric resistance of the amorphous steel sheet is suitable for generating an eddy current, the amorphous core 1 can apply a large rotational torque. Therefore, it is possible to increase the gap between the stator and the rotor despite the poor workability of the amorphous steel sheet. As a result, the mechanical accuracy has a margin, so that the application of the amorphous core 1 to rotating equipment is realistic.

FIG. 3 is an explanatory view showing another embodiment of the present invention in which the number of permanent magnets used in the rotor is increased to four. 3, reference numeral 30 denotes a rotor shaft; 401 to 404, respectively, permanent magnets of the rotor;
0 is a permanent magnet support of the rotor, 60 is an amorphous core, and 70 is an amorphous core support. Shaft 3
0 is assumed to be rotating at the angular velocity ω. In the rotor structure shown in FIG. 3, four permanent magnets 401 to 404 are used, so that four permanent magnets 401 to 404 mounted on the permanent magnet support 50 of the rotor
Act from the direction. For this reason, the effect of the magnetic flux is greater than that of the permanent magnet acting from three directions shown in FIG.

As the laminated core constituting the stator, a laminated system shown in FIGS. FIG. 4A shows a core formed by inserting a laminated electromagnetic steel sheet core 102 in a sandwich shape inside laminated amorphous cores 101 and 103. FIG.
The core shown in (b) is a core in which the cores are arranged vertically and wound and laminated so that the width direction of the amorphous core 104 is in the radial direction of the stator. Although the core shown in FIG. 4B is an amorphous core 104, the radius of the stator needs to be sufficiently larger than the width of the amorphous steel plate.

Conventionally, a permanent magnet is usually used for a rotor of a synchronous motor, and the present invention also uses a permanent magnet. Although it is possible to replace the permanent magnet with an electromagnet, a current supply means for supplying a stable current to the coil of the electromagnet is required. Furthermore, a rotating current collecting means is required to supply current to the rotating coil of the electromagnet. Usually, adding the rotating current collecting means increases the failure rate,
Problems such as an increase in maintenance work are caused. For this reason, the present invention is limited to the use of permanent magnets, but a synchronous motor can be realized even with electromagnets.

[0016]

As described above, the present invention uses a stator in which a laminated amorphous core having a high magnetic permeability is used and a winding for generating a rotating magnetic field by polyphase alternating current is wound on the core. By using a rotor in which two, three, or four permanent magnets are arranged around an amorphous core, the interaction between the stator and the rotor magnetic flux is increased, and the leakage magnetic flux is prevented.
Therefore, there is an effect that a highly efficient synchronous motor can be realized. Further, since the magnetic permeability is large, the stray capacitance is small even with a large inductance, and high-frequency operation is possible.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing an embodiment of a stator of a synchronous motor using a permanent magnet according to the present invention.

FIG. 2 is an explanatory diagram showing one embodiment of a rotor of a synchronous motor using a permanent magnet according to the present invention.

FIG. 3 is an explanatory view showing another embodiment of the rotor of the synchronous motor using the permanent magnet according to the present invention.

FIG. 4 is an explanatory view showing another way of winding a steel plate in the stator of the present invention.

[Explanation of symbols]

1, 60, 6a to 6d, 101, 103, 104 Amorphous core 2 Winding 3, 30, 3a to 3d Shaft 41 to 44, 401 to 404, 41a to 43a, 41b
-43b, 41c-43c, 41d-43d Permanent magnet 50, 5a-5d Permanent magnet support 70, 7a-7d Amorphous core support 102 Electromagnetic steel sheet core

Claims (3)

[Claims] 1. A stator comprising a multi-phase winding wound in a ring around a core obtained by winding a steel plate in a ring shape and laminating the core.
A rotor surrounding the stator by incorporating three, four or four permanent magnets therein, and a rotor rotating inside the stator while exerting an electromagnetic action on the stator. Synchronous motor using. 2. A synchronous motor using a permanent magnet according to claim 1, wherein the core formed by winding the steel sheet in a ring shape and laminating the core is formed by laminating an amorphous steel sheet over the whole, or the amorphous steel sheet is disposed outside. A synchronous motor using a permanent magnet, characterized in that the core is formed by laminating and forming a sandwich structure by laminating electromagnetic steel sheets inside. 3. The synchronous motor using a permanent magnet according to claim 1, wherein the ring-shaped core of the stator is formed by winding an amorphous steel sheet in a tape shape in the circumferential direction of the core a plurality of times and laminating the same. A synchronous motor using a permanent magnet, wherein the core is arranged so that a width direction thereof is in a radial direction of the stator, wound around a plurality of times, and laminated.