Magnetic leakage controllable hybrid permanent magnet variable flux memory motor

Abstract

The invention discloses a magnetic flux leakage controllable hybrid permanent magnet variable flux memory motor, which comprises a stator, a winding, a rotor and a rotating shaft, the stator is provided with the winding, the rotor is fixed on the rotating shaft, and the rotor is provided with a low-coercivity permanent magnet, a high-coercivity permanent magnet, a V-shaped permanent magnet groove with an outward opening, a magnetic barrier and a magnetic bridge. The low-coercive-force permanent magnets comprise first low-coercive-force permanent magnets and second low-coercive-force permanent magnets, the high-coercive-force permanent magnets comprise first high-coercive-force permanent magnets and second high-coercive-force permanent magnets, the V-shaped permanent magnet grooves are uniformly arranged along the circumferential direction of the rotor iron core, and the second low-coercive-force permanent magnets are respectively placed on two sides of each V-shaped permanent magnet groove. The motor has more magnetic leakage branches, so that the magnetic leakage degree of the motor is higher and the air gap flux density is lower under no-load and weak magnetic working conditions; the demagnetization risk of the high-coercivity permanent magnet is reduced, the efficiency is improved, and the requirement for high speed increase is met.

Description

Technical Field

[0001] The invention relates to the field of permanent magnet motors, and in particular to a magnetic leakage controllable hybrid permanent magnet variable flux memory motor. Background Art

[0002] The permanent magnet potential of traditional permanent magnet motors is relatively constant, and the air gap magnetic field is difficult to adjust, which makes it difficult to increase the speed in weak magnetic field, limiting the speed regulation range of the motor. How to improve the efficiency of permanent magnet synchronous motors in medium and high speed operation areas and expand the speed regulation range has become a research hotspot in the field of automotive drive at home and abroad. Therefore, variable leakage permanent magnet synchronous motors that can meet the needs of different operating conditions have received more and more attention. Through the design of magnetic barriers, variable leakage permanent magnet synchronous motors have the characteristics of no leakage under heavy load and more leakage under light load, which can assist in achieving low-speed high torque and high-speed constant power.

[0003] However, the existing variable leakage permanent magnet synchronous motor has the same method as the traditional permanent magnet synchronous motor in weak magnetic field operation, which requires the application of a continuous stator current, which not only increases the loss of the motor, but also increases the risk of irreversible demagnetization of the permanent magnet, reducing the efficiency in the high-speed operation range. At the same time, most of the leakage flux in the existing variable leakage permanent magnet synchronous motor is leakage flux between adjacent poles, and the self-leakage flux is relatively small, which also leads to limited no-load and weak magnetic field efficiency. Summary of the invention

[0004] Purpose of the invention: The purpose of the invention is to provide a hybrid permanent magnet variable flux memory motor with higher no-load and weak magnetic efficiency and controllable magnetic leakage to meet the speed regulation requirements of multiple working conditions.

[0005] Technical solution: The present invention comprises a stator, a winding, a rotor and a rotating shaft, wherein the stator is provided with a winding, and the rotor is fixed on the rotating shaft, and is characterized in that the rotor is provided with a low-coercive force permanent magnet, a high-coercive force permanent magnet, a V-shaped permanent magnet slot opening outward, a magnetic barrier and a magnetic bridge, the low-coercive force permanent magnet comprises a first low-coercive force permanent magnet and a second low-coercive force permanent magnet, the high-coercive force permanent magnet comprises a first high-coercive force permanent magnet and a second high-coercive force permanent magnet, and the V-shaped permanent magnet slot is arranged along the rotor core. The permanent magnets are evenly arranged in the circumferential direction, and the second low coercive force permanent magnet and the first high coercive force permanent magnet or the first low coercive force permanent magnet and the second high coercive force permanent magnet are placed on both sides of each V-shaped permanent magnet slot respectively. The coercive forces of adjacent permanent magnet blocks in adjacent V-shaped permanent magnet slots are the same. The second low coercive force permanent magnet and the first high coercive force permanent magnet or the second high coercive force permanent magnet and the first low coercive force permanent magnet in the same V-shaped permanent magnet slot form a magnetic pole, and the magnetic poles of the permanent magnets in adjacent V-shaped permanent magnet slots are opposite.

[0006] Furthermore, the magnetic barriers include axe-shaped magnetic barriers, arc-shaped magnetic barriers, wedge-shaped magnetic barriers and circular magnetic barriers. A double-layer magnetic barrier is arranged in the iron core between the openings of adjacent V-shaped permanent magnet slots, the outer side is an axe-shaped magnetic barrier, and the inner side is an arc-shaped magnetic barrier opening outward. Auxiliary leakage magnetic paths are arranged between the V-shaped permanent magnet slots, the axe-shaped magnetic barriers, the arc-shaped magnetic barriers and the outer diameter of the rotor.

[0007] Furthermore, the axe-shaped magnetic barrier is arc-shaped near the outer side of the rotor, and is straight-line-shaped on the inner side, and both sides are combined by smooth curves and straight lines.

[0008] Furthermore, the arc-shaped magnetic barrier is arranged inside the axe-shaped magnetic barrier, with its opening facing the outside of the rotor.

[0009] Furthermore, the V-shaped angle of the V-shaped permanent magnet slot is 120 to 180 degrees.

[0010] Furthermore, the magnetic poles of the permanent magnets in two adjacent V-shaped permanent magnet slots are opposite.

[0011] Furthermore, the cross-sections of the low-coercive force permanent magnet and the high-coercive force permanent magnet are rectangular.

[0012] Furthermore, the axe-shaped magnetic barrier is connected to the low-coercive force permanent magnet and the high-coercive force permanent magnet via a circular magnetic barrier.

[0013] Furthermore, the second low-coercive force permanent magnet and the first high-coercive force permanent magnet are connected via a wedge-shaped magnetic barrier, and the first low-coercive force permanent magnet and the second high-coercive force permanent magnet are connected via a wedge-shaped magnetic barrier.

[0014] Furthermore, the low coercive force permanent magnet is an AlNiCo magnet; and the high coercive force permanent magnet is a NdFeB magnet.

[0015] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0016] The magnetic bridge set in the motor structure opens up two self-leakage magnetic flux branches and two adjacent pole-to-pole branches inside the rotor. Compared with the existing variable-leakage permanent magnet synchronous motor, it has more leakage magnetic flux branches. Under no-load and weak magnetic conditions, the motor has a higher leakage magnetic flux and a lower air gap flux density.

[0017] In the motor structure, a low-coercive force permanent magnet and a high-coercive force permanent magnet are placed in the V-shaped permanent magnet slot on the rotor. When the motor is in weak magnetic speed regulation, in addition to regulating the magnetic field by self-leakage and inter-pole leakage, the magnetization state of the low-coercive force permanent magnet is changed by applying an instantaneous demagnetization current pulse to achieve effective regulation of the air gap magnetic field, reducing the risk of demagnetization of the high-coercive force permanent magnet and improving efficiency.

[0018] The permanent magnet arrangement set in the motor structure is such that when the magnetism is weak, by applying demagnetization currents of different sizes, the motor can have two weak-magnetization speed regulation states to meet a variety of working conditions; when a small demagnetization current pulse is applied, the magnetic field strength of the low-coercive force permanent magnet is reduced, reducing the magnetic field passing through the air gap, but the magnetization direction of the permanent magnet remains unchanged, which can meet lower speed-up requirements; when a large demagnetization current pulse is applied, the magnetization direction of the low-coercive force permanent magnet is changed, and a loop is formed between the permanent magnets, which greatly reduces the magnetic field passing through the air gap and meets the high speed-up requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of the present invention;

[0020] Figure 2 It is a radial cross-sectional schematic diagram of the present invention;

[0021] Figure 3 Schematic diagram of the magnetization direction of the permanent magnet on the rotor;

[0022] Figure 4 is the magnetic field line distribution of the motor under no-load condition;

[0023] Figure 5 It is the magnetic field line distribution of the motor under heavy load condition;

[0024] Figure 6 It is the distribution of magnetic lines of force when a small demagnetizing current pulse is applied to the motor during field weakening;

[0025] Figure 7 It is the distribution of magnetic lines of force when a large demagnetizing current pulse is applied to the motor during weak magnetic field;

[0026] Figure 8 It is the distribution of magnetic lines of force after the magnetization direction of the low coercive force permanent magnet is changed after the large demagnetization current pulse is removed from the motor;

[0027] Fig. 9 It is the air gap flux density curve of the motor when the magnetizing direction of the permanent magnet changes under no-load condition;

[0028] Fig.10 It is the air gap flux density curve of the motor when the magnetizing direction of the permanent magnet changes under heavy load;

[0029] Fig.11 It is the air gap flux density curve of the motor when a small demagnetizing current pulse is applied and the magnetizing direction of the permanent magnet is changed;

[0030] Fig.12 It is the air gap flux density curve of the motor when a large demagnetizing current pulse is applied and the magnetizing direction of the permanent magnet changes;

[0031] Fig.13 It is the air gap flux density curve of the motor when the magnetizing direction of the low coercive force permanent magnet changes. DETAILED DESCRIPTION

[0032] The technical solution of the present invention is further described below in conjunction with the accompanying drawings.

[0033] like Figure 1 , 2 As shown, the present invention provides a leakage magnetic controllable hybrid permanent magnet variable flux memory motor, comprising a stator 1, a winding 2, a rotor 3 and a rotating shaft 13, wherein a plurality of stator teeth are arranged on the inner circumference of the stator 1, the winding 2 is embedded between the plurality of stator teeth, and the rotor 3 is coaxially located inside the stator 1 and has slots inside. An air gap is left between the inner wall of the stator 1 and the outer wall of the rotor 3, and the thickness of the air gap is related to the power level of the motor, the selected permanent magnet material, and the processing and assembly process of the stator 1 and the rotor 3.

[0034] The rotor 3 is provided with low-coercive force permanent magnets 9, high-coercive force permanent magnets 12, V-shaped permanent magnet slots 5 with openings facing outward, magnetic barriers 6 and magnetic bridges 4. The V-shaped permanent magnet slots 5 are evenly arranged along the circumferential direction of the rotor core, and the second low-coercive force permanent magnet 8, the first high-coercive force permanent magnet 10 or the first low-coercive force permanent magnet 7, the second high-coercive force permanent magnet 11 are placed on both side wings of each V-shaped permanent magnet slot 5, and the coercive force of adjacent permanent magnet blocks in adjacent V-shaped permanent magnet slots 5 is the same, and they are all low-coercive force permanent magnets 9 or all high-coercive force permanent magnets 12;

[0035] A double-layer magnetic barrier is arranged between the openings of adjacent V-shaped permanent magnet slots 5, the outer side of which is a knife-axe-shaped magnetic barrier 14, and the inner side is an arc-shaped magnetic barrier 15 with an opening facing outward. A magnetic bridge 4 is reserved between the V-shaped permanent magnet slots 5, the knife-axe-shaped magnetic barrier 14, the arc-shaped magnetic barrier 15, and the outer diameter of the rotor to provide a path for magnetic leakage. The design width of each part of the magnetic bridge 4 can ensure that the motor has no magnetic leakage in the magnetization state under load, but has magnetic leakage in the demagnetization state.

[0036] like Figure 3 As shown, the low coercive force permanent magnet 8 and the high coercive force permanent magnet 10 are magnetized along their width direction toward the inside or outside of the rotor; the second low coercive force permanent magnet 8 and the first high coercive force permanent magnet 10 in the same V-shaped permanent magnet slot 5 form a magnetic pole, and the permanent magnet poles in adjacent V-shaped permanent magnet slots 5 are opposite.

[0037] like Figure 4 , 9 As shown, when the motor is running at no-load, there is no armature flux in the stator winding, and the leakage magnetic branch will not be saturated. At this time, the branch magnetic permeability is larger than the air gap. Most of the permanent magnetic flux a passes through the air gap and flows to the stator, and a small part flows to the adjacent magnetic pole through an adjacent pole branch and two self-leakage magnetic branches to flow to its own other magnetic pole, forming inter-pole leakage magnetic c and self-leakage magnetic b respectively. There are three leakage magnetic branches, and the maximum air gap magnetic density is 0.500T. A lower air gap magnetic density can improve the no-load efficiency.

[0038] like Figure 5 , 10 As shown in the figure, when the motor is running under heavy load, the increased cross-axis armature flux q saturates the magnetic bridge and blocks the leakage flux path. The permanent magnet leakage flux b and c disappear, and the permanent magnet flux a all enters the stator through the air gap from the direct axis to generate torque. The maximum air gap flux density is 1.325T, which meets the heavy-load and high-torque requirements of the motor.

[0039] like Figure 6 , 11 As shown in the figure, when the motor enters the weak magnetic state, a small demagnetization current pulse is applied, the direct-axis magnetic flux d is small, there are two self-leakage magnetic fluxes b and two inter-pole leakage magnetic fluxes c, the low coercive force permanent magnet does not change its magnetization direction but the magnetization level is reduced, the main magnetic flux passing through the air gap is reduced, and the maximum air gap magnetic flux density is 0.664T, which meets the lower speed increase requirements.

[0040] like Figure 7 , 12 As shown, when a larger demagnetization current pulse is applied, the direct-axis magnetic flux d is larger, the magnetization direction of the low-coercive force permanent magnet changes, a loop is formed between the permanent magnets, and the maximum air gap flux density is 0.596 T. At the same time, the high-coercive force permanent magnet 12 has self-leakage flux b and inter-pole leakage flux c, which can reduce the risk of demagnetization.

[0041] like Figure 8 , 13 As shown in the figure, when the demagnetization current pulse is removed, a loop is formed between the permanent magnets due to the change in the magnetization direction of the low-coercive force permanent magnets. At the same time, the high-coercive force permanent magnets have self-leakage flux, which greatly reduces the permanent magnet flux flowing into the air gap. The maximum air gap flux density is 0.331T, which meets the higher speed increase requirements of the motor.

Claims

1. A leakage-controllable hybrid permanent magnet variable flux memory motor, comprising a stator (1), a winding (2), a rotor (3) and a rotating shaft (13), wherein the stator (1) is provided with the winding (2), and the rotor (3) is fixed on the rotating shaft (13), characterized in that: The rotor (3) is provided with low-coercive force permanent magnets (9), high-coercive force permanent magnets (12), V-shaped permanent magnet slots (5) with an opening facing outward, magnetic barriers (6) and magnetic bridges (4); the low-coercive force permanent magnets (9) include a first low-coercive force permanent magnet (7) and a second low-coercive force permanent magnet (8); the high-coercive force permanent magnets (12) include a first high-coercive force permanent magnet (10) and a second high-coercive force permanent magnet (11); the V-shaped permanent magnet slots (5) are evenly arranged along the circumferential direction of the rotor core; and each V-shaped permanent magnet slot (5) has two sides. A second low-coercive force permanent magnet (8), a first high-coercive force permanent magnet (10) or a first low-coercive force permanent magnet (7) and a second high-coercive force permanent magnet (11) are placed respectively, the coercive forces of adjacent permanent magnet blocks in adjacent V-shaped permanent magnet slots (5) are the same, the second low-coercive force permanent magnet (8) and the first high-coercive force permanent magnet (10) or the second high-coercive force permanent magnet (11) and the first low-coercive force permanent magnet (7) in the same V-shaped permanent magnet slot (5) form a magnetic pole, and the magnetic poles of the permanent magnets in adjacent V-shaped permanent magnet slots (5) are opposite.

2. The leakage flux controllable hybrid permanent magnet variable flux memory motor according to claim 1, characterized in that: The magnetic barrier (6) comprises a knife-axe-shaped magnetic barrier (14), an arc-shaped magnetic barrier (15), a wedge-shaped magnetic barrier (16) and a circular magnetic barrier (17); a double-layer magnetic barrier is arranged in the iron core between the openings of adjacent V-shaped permanent magnet slots (5); the outer side is a knife-axe-shaped magnetic barrier (14), and the inner side is an arc-shaped magnetic barrier (15) with the opening facing outward; and auxiliary leakage magnetic paths are arranged between the V-shaped permanent magnet slots (5), the knife-axe-shaped magnetic barrier (14), the arc-shaped magnetic barrier (15) and the outer diameter of the rotor.

3. The leakage flux controllable hybrid permanent magnet variable flux memory motor according to claim 2, characterized in that: The axe-shaped magnetic barrier (14) is arc-shaped at the outer side close to the rotor (3), and is straight-line-shaped at the inner side, with both sides being a combination of smooth curves and straight lines.

4. The leakage flux controllable hybrid permanent magnet variable flux memory motor according to claim 2, characterized in that: The arc-shaped magnetic barrier (15) is arranged inside the axe-shaped magnetic barrier (14), with its opening facing the outside of the rotor (3).

5. The leakage flux controllable hybrid permanent magnet variable flux memory motor according to claim 1, characterized in that: The V-shaped angle of the V-shaped permanent magnet slot (5) is 120 to 180 degrees.

6. The leakage flux controllable hybrid permanent magnet variable flux memory motor according to claim 1, characterized in that: The magnetic poles of the permanent magnets in two adjacent V-shaped permanent magnet slots (5) are opposite.

7. The leakage flux controllable hybrid permanent magnet variable flux memory motor according to claim 1, characterized in that: The cross sections of the low-coercive force permanent magnet (9) and the high-coercive force permanent magnet (12) are rectangular.

8. The leakage flux controllable hybrid permanent magnet variable flux memory motor according to claim 1, characterized in that: The axe-shaped magnetic barrier (14) is connected to the low-coercive force permanent magnet (9) and the high-coercive force permanent magnet (12) via a circular magnetic barrier (17).

9. The leakage flux controllable hybrid permanent magnet variable flux memory motor according to claim 1, characterized in that: The second low-coercive force permanent magnet (8) and the first high-coercive force permanent magnet (10) are connected via a wedge-shaped magnetic barrier (16), and the first low-coercive force permanent magnet (7) and the second high-coercive force permanent magnet (11) are connected via a wedge-shaped magnetic barrier (16).

10. The leakage flux controllable hybrid permanent magnet variable flux memory motor according to claim 1, characterized in that: The low coercive force permanent magnet (9) is an aluminum nickel cobalt magnet; the high coercive force permanent magnet (12) is a neodymium iron boron magnet.

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