A permanent magnet synchronous motor rotor with hybrid magnetic steel

Abstract

The purpose of the present invention is to disclose a permanent magnet synchronous motor rotor of hybrid magnetic steel, which is composed of a first magnetic steel, a second magnetic steel, a third magnetic steel and a rotor core, wherein the first magnetic steel, the second magnetic steel and the third magnetic steel are alternately distributed and embedded in the rotor core to form a plurality of magnetic poles; each magnetic pole has N layers of magnetic steel, N is a natural number ≥3, and the first magnetic steel, the second magnetic steel and the third magnetic steel are alternately distributed on the magnetic pole in sequence; compared with the prior art, the multi-layer magnetic steel arrangement is adopted, which can easily obtain better magnetic concentration setting and pole arc coefficient control, solves the contradiction between the structural strength and magnetic isolation effect of the tangential magnetic steel arrangement, and effectively suppresses the performance degradation caused by the motor pole leakage resistance; the layer of the multi-layer magnetic steel close to the outer circle of the rotor core is a radial magnetic steel, which further enhances the magnetic concentration effect and achieves the purpose of the present invention.

Description

Technical Field

[0001] The present invention relates to a motor rotor, in particular to a permanent magnet synchronous motor rotor of hybrid magnetic steel. Background Art

[0002] In the prior art, embedded permanent magnet synchronous motors are increasingly being used because the reluctance torque generated by the asymmetry of their rotor magnetic circuits is beneficial for improving the overload capacity and power density of the motor.

[0003] Traditional rotor magnet arrangements include "I", "V", and "V" + "I", but these magnetic circuit structures contribute little to the motor's reluctance torque and consume a lot of magnets. To increase the proportion of the motor's reluctance torque and improve its field-weakening capability, double "V" and multi-V magnet topologies have emerged in recent years. However, as the number of layers increases, the motor's structural strength deteriorates. Therefore, the application of multi-layer magnet topologies faces increasing challenges as motor speeds increase.

[0004] In addition, there is also a rotor structure with tangentially arranged magnetic steel. The traditional tangentially arranged permanent magnet synchronous motor generally adopts a single-layer tangential magnetic circuit, which has no magnetic concentration ability and is easily demagnetized due to armature reaction.

[0005] Therefore, a permanent magnet synchronous motor rotor with hybrid magnetic steel is particularly needed to solve the above-mentioned existing problems. Summary of the Invention

[0006] The purpose of the present invention is to provide a permanent magnet synchronous motor rotor with hybrid magnetic steel. In response to the shortcomings of the existing technology, it solves the contradiction between the structural strength and magnetic isolation effect of the tangential magnetic steel arrangement, easily obtains better magnetic concentration setting and pole arc coefficient control, effectively suppresses the performance degradation caused by the motor pole leakage resistance, and further enhances the magnetic concentration effect.

[0007] The technical problem solved by the present invention can be achieved by adopting the following technical solutions:

[0008] A hybrid magnetic steel permanent magnet synchronous motor rotor, characterized in that it is composed of a first magnetic steel, a second magnetic steel, a third magnetic steel and a rotor core, wherein the first magnetic steel, the second magnetic steel and the third magnetic steel are alternately distributed and embedded in the rotor core to form a plurality of magnetic poles; each magnetic pole has N layers of magnetic steel, where N is a natural number ≥3, and the first magnetic steel, the second magnetic steel and the third magnetic steel are alternately distributed on the magnetic pole in sequence.

[0009] In one embodiment of the present invention, the first magnetic steel, the second magnetic steel and the third magnetic steel are all symmetrically distributed about the magnetic pole center line.

[0010] In one embodiment of the present invention, within the magnetic pole, an angle between the symmetrically arranged second magnetic steel and the third magnetic steel is equal to 360 degrees divided by the number of poles.

[0011] In one embodiment of the present invention, first slots are provided on the outer circumference side of the magnetic steel slots where the first magnetic steel is located, and the first slots and the outer circumference of the rotor core form a first magnetic isolation bridge.

[0012] In one embodiment of the present invention, the permanent magnet coercivity of the first magnetic steel is lower than that of the second magnetic steel, and the permanent magnet coercivity of the first magnetic steel is lower than that of the third magnetic steel.

[0013] In one embodiment of the present invention, second slots are provided on the outer circumference side of the magnetic steel slots where the second magnetic steel is located, and the second slots and the outer circumference of the rotor core form a second magnetic isolation bridge.

[0014] In one embodiment of the present invention, a third slot hole is provided on each inner circular side of the magnetic steel slot where the second magnetic steel is located, and a second de-duplication hole is provided in the middle of the third slot hole. The second de-duplication hole is polygonal and symmetrical about the center line of the magnetic pole. The second de-duplication hole and the two third slot holes form a second force-bearing magnetic bridge, and the two second force-bearing magnetic bridges are arranged in parallel to form a radial resultant force.

[0015] In one embodiment of the present invention, a fourth slot is provided on the outer circumference side of the magnetic steel slot where the third magnetic steel is located, and the fourth slot and the outer circumference of the rotor core form a third magnetic isolation bridge.

[0016] In one embodiment of the present invention, a fifth slot hole is provided on each inner circular side of the magnetic steel slot where the third magnetic steel is located, and a first deduplication hole is provided in the middle of the fifth slot hole. The first deduplication hole and the two fifth slot holes form a first force-bearing magnetic bridge, and the two first force-bearing magnetic bridges are arranged in parallel to form a radial resultant force.

[0017] Compared with the prior art, the hybrid magnetic steel permanent magnet synchronous motor rotor of the present invention adopts a multi-layer magnetic steel arrangement, which can easily obtain better magnetic concentration setting and pole arc coefficient control, solve the contradiction between the structural strength and magnetic isolation effect of the tangential magnetic steel arrangement, and effectively suppress the performance degradation caused by the motor pole leakage resistance; the layer of the multi-layer magnetic steel close to the outer circle of the rotor core is radial magnetic steel, which further enhances the magnetic concentration effect and achieves the purpose of the present invention.

[0018] The features of the present invention can be clearly understood by referring to the drawings and the following detailed description of preferred embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic structural diagram of the hybrid magnetic steel permanent magnet synchronous motor rotor of the present invention. DETAILED DESCRIPTION

[0020] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the present invention is further described below with reference to specific illustrations.

[0021] Example

[0022] like Figure 1 As shown, the hybrid magnetic steel permanent magnet synchronous motor rotor of the present invention is composed of a first magnetic steel 8, a second magnetic steel 13, a third magnetic steel 4 and a rotor core 16. The first magnetic steel 8, the second magnetic steel 13 and the third magnetic steel 4 are alternately distributed and embedded in the rotor core 16 to form a plurality of magnetic poles; each magnetic pole has N layers of magnetic steel, where N is a natural number ≥3, and the first magnetic steel 8, the second magnetic steel 13 and the third magnetic steel 4 are alternately distributed on the magnetic pole.

[0023] For example, each magnetic pole of the rotor core 16 has N (N is a natural number greater than or equal to 3) layers of magnetic steel, the first layer is composed of one first magnetic steel 8, the second layer is composed of two second magnetic steels 13, the third layer is composed of two third magnetic steels 4, the fourth layer is composed of two magnetic steels..., and the second magnetic steels 13 and the third magnetic steels 4 on both sides of the magnetic pole center line are symmetrically distributed about the magnetic pole center line, and the one first magnetic steel 8 is also symmetrical about the magnetic pole center line.

[0024] In this embodiment, within the magnetic pole, the angle between the two symmetrically arranged third magnetic steels 4 is approximately equal to 360 degrees divided by the number of poles, and the angle between the two symmetrically arranged second magnetic steels 13 is also approximately equal to 360 degrees divided by the number of poles.

[0025] For example, the included angle of the rotor of a 6-pole motor is about 60°, the included angle of the rotor of an 8-pole motor is about 45°, and the included angle of the rotor of a 12-pole motor is about 30°.

[0026] In this embodiment, a first slot hole 9 is provided on the outer circumference side of the magnetic steel slot where the first magnetic steel 8 is located. The first slot hole 9 and the outer circumference of the rotor core 16 form a first magnetic isolation bridge 7. The first magnetic isolation bridge 7 is narrow in size and has a good magnetic isolation effect; a second slot hole 14 is provided on the outer circumference side of the magnetic steel slot where the second magnetic steel 13 is located. The second slot hole 14 and the outer circumference of the rotor core 16 form a second magnetic isolation bridge 15. The second magnetic isolation bridge 15 is narrow in size and has a good magnetic isolation effect; a fourth slot hole 5 is provided on the outer circumference side of the magnetic steel slot where the third magnetic steel 4 is located. The fourth slot hole 5 and the outer circumference of the rotor core 16 form a third magnetic isolation bridge 6. The third magnetic isolation bridge 6 is narrow in size and has a good magnetic isolation effect.

[0027] In this embodiment, the permanent magnet coercive force of the first magnetic steel 8 is different from that of the second magnetic steel 13 and the third magnetic steel 4. The permanent magnet coercive force of the first magnetic steel 8 is lower than that of the second magnetic steel 13 and the third magnetic steel 4.

[0028] In this embodiment, a fifth slot 3 is provided on the inner circular side of the magnetic steel slot where the third magnetic steel 4 is located, and a first de-weighting hole 1 is provided in the middle of the fifth slot 3. The first de-weighting hole 1 and the two fifth slots 3 form a first force-bearing magnetic bridge 2, and the two first force-bearing magnetic bridges 2 are arranged in parallel to form a radial resultant force; a third slot 12 is provided on the inner circular side of the magnetic steel slot where the second magnetic steel 13 is located, and a second de-weighting hole 10 is provided in the middle of the third slot 12. The second de-weighting hole 10 is polygonal and symmetrical about the center line of the magnetic pole. The second de-weighting hole 10 and the two third slots 12 form a second force-bearing magnetic bridge 11, and the two second force-bearing magnetic bridges 11 are arranged in parallel to form a radial resultant force.

[0029] The magnetic steel, magnetic steel slots, magnetic isolation bridges, force magnetic bridges and de-weighting space of the fourth layer are the same as those of the third layer; the magnetic steel, magnetic steel slots, magnetic isolation bridges, force magnetic bridges and de-weighting space of the Nth layer (N is a natural number greater than or equal to 3) are the same as those of the third layer.

[0030] The hybrid magnetic steel permanent magnet synchronous motor rotor of the present invention works as follows:

[0031] When the motor is unloaded, the magnetic bridge where the magnetic steel slots on the rotor are located ensures that the main magnetic lines of force of the magnets flow from the third magnetic steel 4 and the second magnetic steel 13 to the first magnetic steel 8, then penetrate the rotor core to the motor air gap, enter the motor stator, return to the air gap and return to the first magnetic steel 8, the second magnetic steel 13 and the third magnetic steel 4 of the other magnetic pole to form a closed loop;

[0032] When the motor is loaded, the iron core material between the magnets forms magnetic teeth and a sufficiently large cross-axis flux linkage, which produces effective armature magnetization. The magnetic lines of force penetrating the magnetic poles in the direction of the direct axis are effectively restricted by the magnetic bridge of the magnet slots, and the motor generates significant reluctance torque.

[0033] The tangential magnetic steel structure has a magnetic field concentration effect. The third magnetic steel 4 and the second magnetic steel 13 are the main magnetic steels, providing the main magnetomotive force. The radial first magnetic steel 8 is an auxiliary magnetic steel, mainly playing a magnetic field concentration role. The addition of the first magnetic steel 8 can further enhance the magnetic field concentration effect and increase the asymmetry of the dq axis magnetic circuit of the motor, thereby improving the proportion of the motor's reluctance torque. Therefore, low coercive force type permanent magnets can be used;

[0034] When the motor rotates at high speed, each magnetic pole of the motor has two first force-bearing magnetic bridges 2 and two second force-bearing magnetic bridges 11 of relatively wide size, which ensures the mechanical strength of the rotor. Moreover, these magnetic bridges are parallel to the neutral line of the magnetic pole. When the motor rotates at high speed, it is mainly subjected to positive stress, which further ensures the reliability of the high-speed rotation of the rotor.

[0035] The basic principles, main features and advantages of the present invention are shown and described above. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention, which is defined by the appended claims and their equivalents.

Claims

1. A permanent magnet synchronous motor rotor of hybrid magnetic steel, characterized in that: It consists of a first magnetic steel, a second magnetic steel, a third magnetic steel and a rotor core, wherein the first magnetic steel, the second magnetic steel and the third magnetic steel are alternately distributed and embedded in the rotor core to form a plurality of magnetic poles; each magnetic pole has N layers of magnetic steel, N is a natural number ≥3, and the first magnetic steel, the second magnetic steel and the third magnetic steel are alternately distributed on the magnetic pole in sequence; a first slot hole is provided on the outer circle side of the magnetic steel slot where the first magnetic steel is located, and the first slot hole and the outer circle of the rotor core form a first magnetic isolation bridge; a second slot hole is provided on the outer circle side of the magnetic steel slot where the second magnetic steel is located, and the second slot hole and the rotor core form a first magnetic isolation bridge; The outer circle of the iron core forms a second magnetic isolation bridge; a third slot is provided on the inner circle side of the magnetic steel slot where the second magnetic steel is located, and a second de-weighting hole is provided in the middle of the third slot. The second de-weighting hole is polygonal and symmetrical about the center line of the magnetic pole. The second de-weighting hole and the two third slots form a second force-bearing magnetic bridge, and the two second force-bearing magnetic bridges are arranged in parallel to form a radial resultant force; a fourth slot is provided on the outer circle side of the magnetic steel slot where the third magnetic steel is located, and the fourth slot forms a third magnetic isolation bridge with the outer circle of the rotor core; a fifth slot is provided on the inner circle side of the magnetic steel slot where the third magnetic steel is located, and a first de-weighting hole is provided in the middle of the fifth slot. The first de-weighting hole and the two fifth slots form a first force-bearing magnetic bridge, and the two first force-bearing magnetic bridges are arranged in parallel to form a radial resultant force; The second magnetic steel and the third magnetic steel are tangential magnetic steels, and the first magnetic steel is a radial magnetic steel; the permanent magnet coercivity of the first magnetic steel is lower than the permanent magnet coercivity of the second magnetic steel, and the permanent magnet coercivity of the first magnetic steel is lower than the permanent magnet coercivity of the third magnetic steel.

2. The hybrid magnetic steel permanent magnet synchronous motor rotor according to claim 1, characterized in that: The first magnetic steel, the second magnetic steel and the third magnetic steel are all symmetrically distributed about the magnetic pole center line.

3. The hybrid magnetic steel permanent magnet synchronous motor rotor according to claim 1, characterized in that: In the magnetic pole, the angle between the symmetrically arranged second magnetic steel and the third magnetic steel is equal to 360 degrees divided by the number of poles.

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