CN101345442B - Rotor of electric motor used for compressor - Google Patents

Abstract

The invention relates to a rotor of a motor for a compressor. The rotor is provided with an even number of magnet slots, and a permanent magnet is inserted into each magnet slot. The air gap and connecting ribs separate the magnetic isolation air gap from each magnet slot; there is a notch on the outer circumference of the rotor between the magnetic poles of adjacent magnets, and the magnetic isolation bridge separates the magnetic isolation air gap from the notch.

Description

Rotor of motor for compressor

technical field

The invention relates to a permanent magnet motor rotor, in particular to a permanent magnet motor rotor for a compressor.

Background technique

Generally, a permanent magnet motor is composed of an external stator and an internal rotor, wherein stator slots are provided on the stator, windings are embedded in the stator slots, and permanent magnets are inserted in the rotor. The rotor rotates through the interaction of the magnetic field generated by passing current into the fixed stator winding and the magnetic field generated by the permanent magnet of the rotor.

According to the different permanent magnet materials inserted in the rotor of the permanent magnet motor, the existing compressor permanent magnet rotors are divided into two types, one using ferrite permanent magnet materials, and the other using NdFeB permanent magnet materials.

In the rotor using ferrite permanent magnet material, due to the low remanence of ferrite permanent magnet material, the intrinsic coercive force is also small. In order to generate a certain magnetic flux and maintain sufficient anti-demagnetization ability, the permanent magnet's The larger the area and the thickness, the more permanent magnetic materials are used, and the more electromagnetic steel sheets are used.

In the rotor using NdFeB permanent magnet material, the permanent magnet is inserted into the rotor core. Although the magnetic permeability of the permanent magnet is close to that of the air, due to the high remanence of the NdFeB permanent magnet material, the internal The inherent coercive force is relatively large, and the thickness of the permanent magnet material used in the design is relatively thin. The reluctance of the AC-D axis magnetic circuit of the motor is different but not very large, so the available reluctance torque is not large.

Contents of the invention

The purpose of the present invention is to increase the reluctance of the rotor quadrature-axis magnetic circuit, make the quadrature-axis inductance smaller than the direct-axis inductance, and make the difference between the two larger, thereby increasing the available reluctance torque.

The invention provides a rotor of a permanent magnet motor for a compressor. The rotor is provided with an even number of magnet slots, and a permanent magnet is inserted into each magnet slot. A magnetic isolation air gap, the connecting rib separates the magnetic isolation air gap from each magnet slot; there is a notch on the outer circumference of the rotor between the magnetic poles of adjacent magnets, and the magnetic isolation bridge separates the magnetic isolation air gap from the notch.

Through the new rotor shape of the present invention, the quadrature-axis inductance of the compressor motor is smaller than the direct-axis inductance, and positive reluctance torque can be obtained by controlling the current phase angle, thereby increasing the electromagnetic torque generated by the unit current, that is, improving the motor The efficiency, increase the output of the motor.

Description of drawings

The features and advantages of the present invention will become more clear through the detailed description of preferred embodiments of the present invention in conjunction with the accompanying drawings.

Figure 1 shows a schematic diagram of the motor stator and rotor;

Fig. 2 has shown the local schematic diagram of the rotor magnetic isolation air gap of the present invention;

Fig. 3 shows a partial schematic diagram of the magnetic separation air gap of the rotor in the present invention.

Explanation of reference signs:

5—Stator

6—Stator slot

7—Permanent magnet

8 - Shaft

9—rotor core

10—Stator fixing hole

11—rotor rivet hole

12—rotor magnetic isolation air gap

13—rotor peripheral notch

14—Magnetic Isolation Bridge

15—Magnet Slot

16—Magnetic pole

17—connecting rib

21—Stator winding

Detailed ways

FIG. 1 shows a schematic diagram of a stator and rotor of an electrical machine, which is formed from an outer stator 5 and an inner rotor 9 . Wherein, a plurality of stator slots 6 uniformly distributed along the circumferential direction are arranged in the stator 5 , and windings 21 are embedded in the stator slots 6 . An even number of magnet slots 15 are arranged at equal intervals along the circumference on the rotor 9 punching piece, and a permanent magnet 7 is inserted in each magnet slot 15, and the polarities of two adjacent permanent magnets 7 are opposite. It can be clearly seen from FIG. 2 that a magnetic isolation air gap 12 is provided between adjacent magnet slots 15 , and the connecting ribs 17 separate the magnetic isolation air gap 12 from each magnet slot 15 . In addition, a notch 13 is provided on the outer circumference of the rotor between the magnetic poles 16A and 16B of the adjacent permanent magnets 7, and the magnetic isolation bridge 14 connecting the adjacent magnetic poles 16A and 16B is located between the magnetic isolation air gap 12 and the notch 13 space so as to separate the magnetic isolation air gap 12 from the notch 13 . In this way, the magnetic isolation air gap 12 is located on the quadrature axis magnetic circuit of the rotor, so that the reluctance of the quadrature axis magnetic circuit is greater than that of the direct axis magnetic circuit. Since the magnetic isolation air gap 12 and the groove 13 are located on the quadrature-axis magnetic circuit of the rotor, and the magnetic permeability of the air is very small, the reluctance of the quadrature-axis magnetic circuit is much larger than that of the direct-axis magnetic circuit. The larger is the reluctance torque generated by the difference between the reluctance of the orthogonal and direct axes.

FIG. 3 shows a partial schematic diagram of the rotor magnetic isolation air gap 12 in the present invention, and the magnetic isolation air gap 12 shown is polygonal. Wherein, the ratio of the upper width A to the lower width B of the magnetic isolation air gap 12 is between 0.5 and 1.2. And the ratio of the upper width A to the thickness of the permanent magnet 7 in the radial direction is between 1.5-3. The ratio of the thickness of the side C of the magnetic isolation air gap 12 opposite to the magnet groove 15 and the thickness of the permanent magnet 7 in the radial direction is between 0.8 and 2. In addition to the shape shown in the figure, the magnetic isolation air gap 12 can be other Polygons in shape, as long as they have similar functions, are within the scope of this patent.

Claims (5)

1. a rotor (9) of a permanent magnet motor for a compressor, which rotor (9) is provided with an even number of magnet slots (15), inserts a permanent magnet in each magnet slot (15), is characterized in that: A magnetic separation air gap (12) is provided between adjacent magnet grooves (15), and connecting ribs (17) separate the magnetic separation air gap (12) from each magnet groove (15); A notch (13) is provided on the outer circumference of the rotor between (16A, 16B), and the magnetic isolation bridge (14) separates the magnetic isolation air gap (12) from the notch (13). 2. The rotor according to claim 1, characterized in that the magnetic isolation air gap (12) is polygonal in shape. 3. The rotor according to claim 1 or 2, characterized in that the ratio of the upper width (A) to the lower width (B) of the magnetic isolation air gap (12) is between 0.5 and 1.2. 4. The rotor according to claim 1 or 2, characterized in that the ratio of the upper width (A) of the magnetic isolation air gap (12) to the thickness of the permanent magnet (7) in the radial direction is between 1.5 and 3 between. 5. The rotor according to claim 1 or 2, characterized in that: the side width (C) of the magnetic separation air gap (12) opposite to the magnet slot (15) is the same as that of the permanent magnet (7) in the radial direction The thickness ratio is between 0.8 and 2.

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