KR100876173B1 - Rotor manufacturing method for reluctance motor using magnetic anisotropy of oriented electrical steel sheet - Google Patents

Abstract

The present invention relates to a method for manufacturing a rotor for a reluctance motor using magnetic anisotropy of a grain-oriented electrical steel sheet, the method for manufacturing a rotor for a reluctance motor; The rotor is composed of two poles, N-pole and S-pole with magnetic flux barrier, and the main magnetic flux direction of the two-pole rotor coincides with the rolling direction of the oriented electrical steel sheet, and the rolling perpendicular direction and the magnetic flux barrier of the oriented electrical steel sheet. It provides a method for manufacturing a rotor for a reluctance motor using the magnetic anisotropy of the grain-oriented electrical steel sheet is formed to match the center direction of the.

Accordingly, the present invention is to achieve the maximal pole ratio and improved torque characteristics by manufacturing the rotor of the reluctance motor operated by the magnetoresistance difference by using the unidirectional high permeability oriented electrical steel sheet, thereby improving the efficiency of the motor, It enables high output and small size.

Description

Method for manufacturing rotor for reluctance motor using magnetic anisotropy of oriented electrical steel sheet TECHNICAL FOR MANUFACTURING RELUCTANCE MOTOR ROTOR USING MAGNETIC ANISOTROPIC OF ORIENTED ELECTRICAL STEEL SHEET

1 is a conceptual diagram showing the structure of a general permanent magnet motor using electromagnetic torque,

2 is a conceptual diagram showing the structure of a reluctance motor having four poles;

3 is an enlarged view illustrating main parts of FIG. 2;

4 is an exemplary schematic view showing the shape of a rotor and its magnetic flux designed in two poles according to the present invention;

5 is an exemplary view showing a manufacturing process of the rotor according to the present invention;

6 is an exemplary perspective view showing a laminated state of the rotor according to the present invention.

♧ description of the symbols for the main parts of the drawing ♧

100 .... N-pole 110 .... S-pole

200 .... magnetic flux 300 .... loop

The present invention relates to a method for manufacturing a rotor for a reluctance motor using magnetic anisotropy of a grain-oriented electrical steel sheet. More particularly, the present invention relates to a method of manufacturing a rotor having a magnetic anisotropy. The present invention relates to a rotor manufacturing method for a reluctance motor using magnetic anisotropy of an electrical steel sheet.

In general, a motor is composed of a conductor for supplying power and an iron core provided in a mechanism capable of mounting the conductor, and each component serves as a path for transmitting electric energy and magnetic energy.

At this time, the magnetic material constituting the magnetic circuit in the mechanism determines the performance of the motor, the electrical steel sheet of the magnetic material has been adopted in most motors as an important functional material to minimize the iron loss of the motor.

In particular, as the industrial system is diversified and the demand for energy saving is increased, various power converters tend to become high output, high efficiency, and high performance, and heat and loss generated by these factors not only lower efficiency but also hinder design freedom. Recently, high-grade non-oriented electrical steel sheet with low iron loss of 3.0-2.0W / kg has been used.

The torque generating principle of the motors using the electrical steel is largely a method of using electromagnetic torque and a method of using reluctance torque. In recent years, hybrid forms incorporating them have been developed.

For example, a motor using electromagnetic torque includes a permanent magnet brushless motor, an induction motor, a DC motor, and the like, and a motor using reluctance torque includes a synchronous reluctance motor and a switched reluctance motor.

Here, in the case of a motor using electromagnetic torque, as in the example of Figure 1, the stator 1 is composed of a tooth 2 and a slot (3) structure, mainly used by laminating a single sheet of electrical steel sheet; The rotor is composed of a permanent magnet (4) and the rotating shaft (5), the ends of the rotating shaft (5) is provided in a form that is fixed to the bearing so as to be rotatable.

Thus, a predetermined driving torque is generated by the electromagnetic force caused by the interaction between the magnetic pole generated when the current flows through the stator coil and the N and S poles of the permanent magnet 4.

In addition, in the case of a motor using reluctance torque, as shown in FIGS. 2 and 3, the stator and the lamination form in which the coil can be mounted are the same as those in FIG. 1, but the magnetic flux barrier 8 in which the rotor is formed on the lip 9 is illustrated. Is configured to have a salience. Thus, when a magnetic field is given to the stator, it is rotated by reluctance torque that aligns to minimize reluctance (maximum inductance).

At this time, the magnetic flux main path direction of the rotor is defined as the d-axis, the central direction of the magnetic flux barrier (8) as the q-axis, the magnetic flux barrier (8) is made of air to minimize the magnetic flux passing through the q-axis.

That is, the d-axis has a small magnetic resistance and a large inductance because the magnetic circuit is composed of only the iron core, while the q-axis has a very high magnetic resistance compared to the d-axis due to the magnetic flux barrier 8 of the rotor and thus the inductance is small. As a result, considering that the inductance is inversely related to the magnetoresistance, it can be seen that the torque can be increased as the difference between the salient pole ratios, that is, the difference between Ld and Lq of Equation 1 below.

(Equation 1)

T = 3/2 × p / 2 (Ld-Lq) × 1/2 × Ia ² × sin2φ

(T is torque, Ld is d-axis inductance, Lq is q-axis inductance, Ia is stator current and φ is phase)

Therefore, the salient pole ratio is an important motor design variable, and in order to make this larger, the number, width, shape, and the like of the magnetic flux barrier 8 are adjusted. However, only the shape design of the rotor iron core core has a limitation of mechanical strength at the lip 9 and a processing limitation.

The present invention was created in view of the limitations of the prior art as described above, focusing on the magnetic anisotropy characteristics of oriented electrical steel sheet, and designing the rotor through this material, regardless of the shape of the rotor. The main object of the present invention is to provide a rotor manufacturing method for a reluctance motor using magnetic anisotropy of a directional electrical steel sheet to maximize the torque of the reluctance motor.

The present invention in order to achieve the above technical problem, a rotor manufacturing method for a reluctance motor; The rotor is composed of two poles, N-pole and S-pole with magnetic flux barrier, and the main magnetic flux direction of the two-pole rotor coincides with the rolling direction of the oriented electrical steel sheet, and the rolling perpendicular direction and the magnetic flux barrier of the oriented electrical steel sheet. It provides a method for manufacturing a rotor for a reluctance motor using the magnetic anisotropy of the grain-oriented electrical steel sheet is formed to match the center direction of the.

At this time, when cutting and punching the rotor in the slitting loop, the magnetic flux main path direction of the rotor is made to match the rolling direction, and even when laminating each sheet, the magnetic flux main path direction is the same without rotation. It is also characterized by being stacked so as to be stacked in the axial direction.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment according to the present invention.

Figure 4 is an exemplary schematic view showing the shape and magnetic flux of the rotor designed in two poles according to the present invention, Figure 5 is an exemplary view showing a manufacturing process of the rotor according to the invention, Figure 7 according to the present invention Exemplary perspective view showing the lamination state of the rotor.

As is well known, electrical steel sheet is divided into oriented electrical steel sheet and non-oriented electrical steel sheet, and directional electrical steel sheet refers to a steel sheet arranged in one direction to facilitate magnetization in the rolling direction, and is mainly used for stops such as transformers and reactors. ; Non-oriented electrical steel sheet refers to a steel sheet made easy to magnetize in all directions, and is mainly used for a rotor such as a motor.

Therefore, the rolling direction of the grain-oriented electrical steel sheet is easy to magnetize, so the magnetic permeability is very high, but the perpendicular to the rolling direction is difficult to magnetize, and the permeability is relatively low compared to the rolling direction. That is, the difference in magnetoresistance in the two directions is much larger than the non-oriented electrical steel sheets generally used in motors.

As a result, when the magnetic anisotropy is applied to the reluctance motor, the breakthrough ratio can be easily improved regardless of the shape of the rotor core.

The present invention, in order to maximize the improvement of the pole-pole ratio, the rotor is composed of a magnetic circuit to have two poles of N pole and S pole, magnetization of the electrical steel sheet d-axis magnetic path of the rotor defined in the direction of the magnetic flux main path The q-axis defined as the easy direction, that is, the rolling direction, and the center direction of the magnetic flux barrier is set to be the difficult direction of magnetization of the electrical steel sheet, that is, the direction perpendicular to the rolling direction.

At this time, the shape of the iron core of the rotor is not particularly limited, for example, can be applied regardless of the shape and dimensions of the magnetic flux barrier, the shape and dimensions of the lip, the magnetic flux barrier and the number of ribs.

In addition, the present invention can be applied to both the case of attaching or inserting a permanent magnet inside the rotor for additional function improvement of the motor, having a conductive conductor bar, or employing an inverter for controlling the motor.

As shown in Figure 4, the rotor according to the present invention is composed of two poles of the north pole and the south pole, the magnetic flux generated by the current of the stator passes between the barrier and the barrier with high permeability .

That is, the process proceeds in the q-axis direction in FIG. 4.

This rotor is formed by cutting from the slitting loop 300, as shown in Figures 5 to 6, in this cutting to match the d-axis of the rotor in the rolling direction of the steel sheet, It is preferable to punch or cut the iron core by matching the q-axis.

Thereafter, the cut sheets are stacked in the axial direction so that the magnetic flux main path directions are equally stacked.

Here, the punching method in the production of the iron core can be a method such as a mold or wire writing, and the lamination method can be caulking, interlocking, clips, welding, bolting, etc., it can be applied regardless of the lamination rotation. .

However, in order to take full advantage of the magnetic anisotropy of the grain-oriented electrical steel sheet, which is a key feature of the present invention, a lamination-free lamination method is more preferable than rotation lamination in sheet lamination.

Hereinafter, an Example is described.

EXAMPLE

A rotor for a reluctance motor was produced by the method according to the invention using a oriented electrical steel sheet.

At this time, the stator used a general non-oriented electrical steel sheet, and the magnetic properties in the rolling direction and the perpendicular to the rolling direction of the grain-oriented electrical steel sheet to be used in the rotor is shown in Table 1.

Here, the size of the magnetic test specimen was used 500 × 500mm, the magnetic permeability was measured at a magnetic flux density of 1.5 Tesla using a unidirectional measuring device.

Then, the pole ratio was calculated using the magnetic anisotropy, and the torque was calculated from the inductance difference between the d-axis and the q-axis, which are shown in Table 2.

 division  Rolling Permeability (Rmu)  Rolling Permeability Perpendicular (Cmu)  Permeability Ratio (Rmu / Cmu)  Non-oriented electrical steel sheet  -  -  1.07  Oriented electrical steel sheet  A  31,396  306  102  B  21,104  281  75

As shown in Table 1, it can be seen that the permeability of the rolling direction and the direction perpendicular to the rolling direction differs by a hundred times as the measured permeability of each direction, which is very high compared to the conventional non-oriented electrical steel sheet.

In addition, in comparison with the measured pole ratio and the resulting torque, it can be seen that the application of the grain-oriented electrical steel sheet improved the pole-pole ratio by approximately 5% or more and the torque characteristics by 5% or more than the conventional non-oriented electrical steel sheet material. .

 division  Breakthrough ratio (Ld / Lq)  Breakthrough ratio improvement (%)  Torque improvement rate (%)  Conventional  13.766  One  One  Invention  A  14.556  5.74  5.35  B  14.560  5.77  5.00

As described in detail above, the present invention achieves the maximization of the pole pole ratio and the improvement of the torque characteristics by manufacturing the rotor of the reluctance-type motor operated by the magnetoresistance difference using the unidirectional high permeability oriented electrical steel sheet, It enables high efficiency, high output and small size of motor.

Claims (2)

A method of manufacturing a rotor for a reluctance motor; The rotor is made of two poles N and S poles with a magnetic flux barrier, made of oriented electrical steel sheet, The magnetic flux main path direction of the bipolar rotor to match the rolling direction of the grain-oriented electrical steel sheet, A method for manufacturing a rotor for a reluctance motor using the magnetic anisotropy of a grain oriented electrical steel sheet formed by matching the rectangular direction of rolling of the grain oriented electrical steel sheet with the center direction of the magnetic flux barrier. The method according to claim 1; When cutting and punching the rotor in the slitting loop, the magnetic flux main path direction of the rotor should be matched with the rolling direction, and the magnetic flux main path directions are stacked the same without rotation even when each sheet is laminated. Rotor manufacturing method for a reluctance motor using the magnetic anisotropy of the grain-oriented electrical steel sheet characterized in that it is stacked in the axial direction.

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