A series magnetic circuit self-leakage magnetic type variable flux memory motor

Abstract

The application discloses a series magnetic circuit self-leakage magnetic type variable magnetic flux memory motor and relates to the technical field of motors.The application comprises a stator, a rotor and a winding, the rotor is provided with a first permanent magnet, a second permanent magnet, a third permanent magnet, a fan-shaped magnetic barrier and a magnetic bridge, the first permanent magnet and the second permanent magnet are uniformly distributed in a first layer and a second layer of rotor iron cores in a one-word type, a fan-shaped magnetic barrier is arranged between the two first permanent magnets, the third permanent magnet is uniformly distributed in the rotor iron core in a spoke shape, the fan-shaped magnetic barrier is respectively provided with a magnetic bridge between the permanent magnet and the outer edge of the rotor, and the first permanent magnet is respectively provided with the second permanent magnet and the third permanent magnet to form a series magnetic circuit.The application can break through the bottleneck problem of a narrow magnet adjustment range of a traditional series built-in variable magnetic flux memory motor, can maintain high torque density, can reduce the amplitude of a required demagnetizing current and can widen the high-efficiency operation range of the motor.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of electric machines, in particular to a series magnetic circuit self-leakage magnetic variable flux memory motor. BACKGROUND

[0002] Due to the high performance of rare earth permanent magnet materials, permanent magnet motors mainly using neodymium iron boron permanent magnets have the advantages of high power density, high efficiency, and various structural designs and simple topologies. However, the relatively constant permanent magnet flux linkage is difficult to adjust, and the back electromotive force is high when the motor runs at high speed. The traditional permanent magnet motor generally realizes flux weakening by applying a continuous negative direct-axis current component, which increases the irreversible demagnetization risk of the permanent magnet, causes additional copper loss, and reduces the operating efficiency.

[0003] In order to improve the full-range efficient operation range of the permanent magnet synchronous motor, a hybrid permanent magnet memory motor using high-coercivity constant flux permanent magnets and low-coercivity variable flux permanent magnets is widely studied. This type of variable flux memory motor not only inherits the advantages of high torque density and high power density of permanent magnet motors, but also has the advantage of easy adjustment of the magnetic field. Only a transient demagnetizing current pulse needs to be applied to realize effective adjustment of the air gap magnetic field.

[0004] In the series magnetic circuit hybrid permanent magnet memory motor, the magnetic flux of the high-coercivity permanent magnet can directly pass through the low-coercivity permanent magnet, which will obviously enhance the load stability of the motor. However, due to the stability of the high-coercivity permanent magnet, the low-coercivity permanent magnet of this type of structure is difficult to demagnetize, and there are problems of narrow magnetic adjustment range and large required magnetization current amplitude. Therefore, we propose a series magnetic circuit self-leakage magnetic variable flux memory motor. SUMMARY

[0005] The purpose of the application is to provide a series magnetic circuit self-leakage magnetic variable flux memory motor. The magnetic bridge saturation conditions are different when the motor is in different states of magnetic enhancement and demagnetization under load conditions. The torque output capacity is guaranteed, and the magnetic adjustment range and speed operation range of the motor are improved, that is, the bottleneck of narrow magnetic adjustment range and difficult demagnetization of the series variable flux memory motor is broken through, high torque density is realized, the demagnetization current amplitude is reduced, and the high efficient operation range of the motor is widened.

[0006] To achieve the above purpose, the application provides the following technical scheme: a series magnetic circuit self-leakage magnetic variable flux memory motor, comprising a stator, a winding and a rotor, characterized in that the stator and the rotor are coaxially sleeved, and a uniform air gap is arranged between the stator and the rotor, and a first permanent magnet, a second permanent magnet, a third permanent magnet, a fan-shaped magnetic barrier and a magnetic bridge are arranged on each pole unit of the rotor.

[0007] The first permanent magnet is uniformly distributed in a linear shape on the first layer of rotor iron cores on the side of the rotor close to the outer edge, the second permanent magnet is uniformly distributed in a linear shape in a circumferential direction on the second layer of rotor iron cores on the side of the rotor close to the inner edge, the third permanent magnet is radially distributed in a spoke shape on the rotor iron cores, and is located on the inner side of the rotor and between adjacent second permanent magnets, the sector-shaped magnetic barriers are distributed between adjacent first permanent magnets and are located at the outer edge of the rotor and on the outer side of the third permanent magnets, and the magnetic bridges between the first permanent magnets and the sector-shaped magnetic barriers, between the third permanent magnets and the sector-shaped magnetic barriers, and between the outer edge of the rotor and the sector-shaped magnetic barriers provide paths for magnetic leakage.

[0008] Further, the cross sections of the first permanent magnets and the second permanent magnets are rectangular, and the magnetization directions are parallel to the short side length directions of the first permanent magnets and the second permanent magnets.

[0009] Further, the first permanent magnet is a low-coercivity permanent magnet, the second permanent magnet and the third permanent magnet are high-coercivity permanent magnets, the first permanent magnet and the second permanent magnet and the third permanent magnet form a series magnetic circuit, the second permanent magnet is unidirectionally magnetized along the magnetization direction, the first permanent magnet is bidirectionally magnetized along the magnetization direction, and the magnetization direction of the first permanent magnet is consistent with that of the second permanent magnet in the magnetization state and is opposite to that of the second permanent magnet in the demagnetization state.

[0010] It should be understood that high coercivity and low coercivity are two relative quantities, and the high-coercivity permanent magnet in the application has higher coercivity than the low-coercivity permanent magnet. In commonly used permanent magnets, the low-coercivity permanent magnet can be selected as an aluminum-nickel-cobalt permanent magnet or a samarium-cobalt permanent magnet, and the high-coercivity permanent magnet can be selected as a neodymium-iron-boron permanent magnet.

[0011] Further, the third permanent magnet and the sector-shaped magnetic barrier are both distributed on the central axes of adjacent first permanent magnets, and the symmetry axes of the third permanent magnet and the sector-shaped magnetic barrier coincide, the third permanent magnet is unidirectionally magnetized along the magnetization direction, and the magnetization direction of the third permanent magnet is parallel to the short side length direction of the third permanent magnet.

[0012] Further, the magnetization directions of adjacent first permanent magnets, adjacent second permanent magnets, or adjacent third permanent magnets are opposite.

[0013] The application has at least the following beneficial effects:

[0014] 1) The magnetic bridge provided in the application opens an additional magnetic leakage path in the rotor of the variable flux memory motor, can expand the magnet adjustment range of the motor, breaks through the bottleneck of narrow magnet adjustment range and large demagnetization current required by the series type variable flux memory motor, and provides a train of thought for widening the magnet adjustment range and reducing the demagnetization current amplitude of the series type, parallel type and hybrid type variable flux memory motor.

[0015] 2) The magnetic bridge provided in this invention provides a leakage flux switch. When the motor is in the magnetization state, the magnetic bridge is saturated and there is almost no leakage flux, thus ensuring high torque density. When the motor is in the magnetization state, the magnetic bridge is desaturated and provides a path for permanent magnet flux, reducing the air gap magnetic flux density, thereby reducing the difficulty of motor magnetization and inverter capacity, and expanding the high-efficiency operating range of the motor.

[0016] 3) The magnetic bridge set in this invention can solve the problems of narrow magnetic adjustment range and the need for high magnetization current level. Therefore, it does not have to compromise on magnetic adjustment range like the existing series magnetic circuit memory motor. It can fully inherit the advantages of the series magnetic circuit memory motor. In this embodiment, it is manifested by the addition of a high coercivity permanent magnet in the second layer, which is beneficial to improve the motor torque density and stabilize the operating point of the low coercivity permanent magnet.

[0017] 4) The setting of magnetic barriers at the q-axis (i.e., the quadrature axis) of the motor can reduce the influence of armature reaction on the permanent magnet field and improve the output capacity of the motor.

[0018] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the cross-sectional structure of the present invention;

[0020] Figure 2 This is a diagram showing the magnetic field distribution under rated load in the magnetized state of this invention;

[0021] Figure 3 This is a diagram showing the distribution of magnetic field lines under rated load in the demagnetized state of this invention.

[0022] Figure label:

[0023] 11. Stator; 12. Winding; 2. Rotor; 31. First permanent magnet; 32. Second permanent magnet; 33. Third permanent magnet; 4. Magnetic barrier; 5. Magnetic bridge. Detailed Implementation

[0024] The technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments of this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0025] Please see Figure 1The application provides a technical scheme: a series magnetic circuit self-leakage magnetic type variable magnetic flux memory motor, which comprises a stator 11, a winding 12 and a rotor 2, a plurality of stator teeth are arranged on the inner circumference of the stator 11, the winding 12 is embedded in the plurality of stator teeth, the rotor 2 is coaxially arranged in the stator 11, an air gap is arranged between the inner wall of the stator 11 and the outer wall of the rotor 2, and the rotor 2 is provided with a first permanent magnet 31, a second permanent magnet 32, a third permanent magnet 33, a fan-shaped magnetic barrier 4 and a magnetic bridge 5.

[0026] The first permanent magnet 31 is fixedly embedded on each pole of the rotor 2 and is distributed in a circumferential “-” shape, the first permanent magnet 31 is located in the first layer of rotor iron cores on the side close to the air gap of the outer edge of the rotor 2, the first permanent magnet 31 is a low-coercivity permanent magnet, the cross section of the first permanent magnet 31 is rectangular, the magnetization direction of the first permanent magnet 31 is parallel to the short side length direction, and the first permanent magnet 31 is bidirectionally magnetized along the magnetization direction, that is, in the magnetized state, the magnetization direction of the first permanent magnet 31 is consistent with the magnetization direction of the second permanent magnet 32; in the demagnetized state, the magnetization direction of the first permanent magnet 31 is opposite to the magnetization direction of the second permanent magnet 32; the magnetization direction and the magnetization state of the first permanent magnet 31 can be changed by a d-axis (i.e. a direct axis) magnetization pulse current.

[0027] It should be noted that the radial symmetry axis of the first permanent magnet 31 coincides with the pole center line of the rotor 2, and the magnetization directions of adjacent first permanent magnets 31 are opposite.

[0028] The second permanent magnet 32 is fixedly embedded on each pole of the rotor 2 and is distributed in a circumferential “-” shape, the second permanent magnet 32 is located in the second layer of rotor iron cores on the side close to the inner edge of the rotor 2, the second permanent magnet 32 is a high-coercivity permanent magnet, the cross section of the second permanent magnet 32 is rectangular, the magnetization direction of the second permanent magnet 32 is parallel to the short side length direction, and the second permanent magnet 32 is unidirectionally magnetized along the magnetization direction, the magnetization direction of the second permanent magnet 32 is consistent with the magnetization direction of the first permanent magnet 31 in the magnetized state, and the second permanent magnet 32 and the first permanent magnet 31 form a series structure.

[0029] It should be noted that the radial symmetry axis of the second permanent magnet 32 coincides with the pole center line of the rotor 2, and the magnetization directions of adjacent second permanent magnets 32 are opposite.

[0030] The third permanent magnet 33 is fixedly embedded between adjacent poles of the rotor 2 and is distributed in a spoke shape on the rotor iron core, the third permanent magnet 33 is a high-coercivity permanent magnet, the cross section of the third permanent magnet 33 is rectangular, the magnetization direction of the third permanent magnet 33 is parallel to the short side length direction, and the third permanent magnet 33 is unidirectionally magnetized along the magnetization direction, and the third permanent magnet 33 and the first permanent magnet 31 form a series structure.

[0031] It should be noted that the radial symmetry axis of the third permanent magnet 33 coincides with the central axis of the adjacent two first permanent magnets 31, and the magnetization directions of adjacent third permanent magnets 33 are opposite.

[0032] The fan-shaped magnetic barrier 4 is located at the central axis of two adjacent first permanent magnets 31, is arranged with the same axis as the third permanent magnet 33, is located outside the third permanent magnet 33, and magnetic bridges 5 are arranged between the first permanent magnet 31 and the fan-shaped magnetic barrier 4, between the third permanent magnet 33 and the fan-shaped magnetic barrier 4, and between the rotor outer edge and the fan-shaped magnetic barrier 4, that is, the self-leakage magnetic path, and the design width of the magnetic bridge 5 can make the motor have no leakage in the magnetic state under load and have leakage in the demagnetization state.

[0033] In combination Figure 2 and Figure 3 It can be seen from the drawings that the self-leakage magnetic type variable magnetic flux memory motor of the series magnetic circuit can realize the working principle of wide magnetic adjustment range, high torque and wide operation range as follows:

[0034] 1) In the rated load operation in the magnetic state, as shown in Figure 2 The magnetic lines of the second permanent magnet 32 and the third permanent magnet 33 pass through the first permanent magnet 31, the high-coercivity and low-coercivity permanent magnet magnetic fluxes are in the same direction, the magnetization state of the first permanent magnet 31 is relatively high, and the magnetic bridge 5 is in a saturated state due to the armature reaction caused by the load armature, so that the magnetic lines of the high-coercivity permanent magnet pass through the first permanent magnet 31 into the air gap and the stator 11, and almost no leakage occurs through the magnetic bridge, so that the air gap magnetic flux is relatively large, and high torque output can be realized.

[0035] 2) In the rated load operation in the demagnetization state, as shown in Figure 3 Due to the demagnetization of the first permanent magnet by the d-axis pulse current, the magnetic bridge 5 exits the saturation state, and a large amount of permanent magnet magnetic flux of the high-coercivity permanent magnet no longer passes through the first permanent magnet 31, that is, the permanent magnet magnetic flux leaks along the magnetic bridge 5, the air gap magnetic flux decreases, and the demagnetization current amplitude of the series magnetic circuit memory motor can be effectively reduced, and high-speed operation can be easily realized.

[0036] As described above, the reasonable setting of the magnetic bridge makes the motor only have self-leakage in the rotor 2 in the demagnetization state, so that the motor has the advantages of wide magnetic adjustment range, high torque density, low demagnetization current amplitude and wide speed expansion ratio.

[0037] It should be noted that in this document, relational terms such as first and second and the like can only be used to distinguish one entity or action from another entity or action, without necessarily requiring or implying that there is any such actual relationship or order between these entities or actions. In addition, the terms "comprises", "comprising" or any other variations thereof are intended to cover non-exclusive inclusions, so that a process, method, article or apparatus including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such a process, method, article or apparatus.

[0038] Those of ordinary skill in the art, in light of the present disclosure, will appreciate that the above-mentioned terms are comprehended in their specific meanings in the present application. When an element is referred to as being "assembled to", "attached to", "fixed to" or "disposed to" another element, it can be directly on the other element or there can be an intervening element. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or there can be an intervening element. The terms "vertical", "horizontal", "upper", "lower", "left", "right", and similar expressions used herein are for illustrative purposes only and are not intended to be limiting.

[0039] Although embodiments of the present application have been shown and described, it will be appreciated by those of ordinary skill in the art that various changes, modifications, alternatives, and variations can be made in the embodiments without departing from the principles and spirit of the application, the scope of which is defined by the appended claims and their equivalents.

[0040] In the description of the specification, the description using the terms "one embodiment", "an example", "a specific example", and the like means that the specific feature, structure, material or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present disclosure. Descriptive expressions of the above terms in the specification do not necessarily refer to the same embodiment or example. Also, the specific features, structures, materials or characteristics described can be combined in any suitable manner in one or more embodiments or examples.

Claims

1. A series magnetic circuit self-leakage type variable flux memory motor, comprising a stator (11), windings (12) and a rotor (2), characterized in that, The stator (11) and rotor (2) are coaxially sleeved and a uniform air gap is provided between them. Each pole unit of the rotor (2) is provided with a first permanent magnet (31), a second permanent magnet (32), a third permanent magnet (33), a fan-shaped magnetic barrier (4) and a magnetic bridge (5). The first permanent magnet (31) is evenly distributed in a straight line on the first layer of rotor core near the outer edge of the rotor (2). The second permanent magnet (32) is evenly distributed in a straight line circumferentially on the second layer of rotor core near the inner edge of the rotor (2). The third permanent magnet (33) is evenly distributed radially in a spoke-like shape on the rotor core, and it is located inside the rotor (2) and between adjacent second permanent magnets (32). The fan-shaped magnetic barrier (4) is distributed between adjacent first permanent magnets (31) and is located at the outer edge of the rotor (2), while it is located outside the third permanent magnet (33). There are magnetic bridges (5) between the first permanent magnet (31) and the sector magnetic barrier (4), between the third permanent magnet (33) and the sector magnetic barrier (4), and between the outer edge of the rotor (2) and the sector magnetic barrier (4) to provide a path for leakage magnetic flux. The first permanent magnet (31) is a low coercivity permanent magnet, and the second permanent magnet (32) and the third permanent magnet (33) are both high coercivity permanent magnets. The first permanent magnet (31) forms a series magnetic circuit with the second permanent magnet (32) and the third permanent magnet (33). The second permanent magnet (32) is unidirectionally magnetized along the magnetization direction, and the first permanent magnet (31) is bidirectionally magnetized along the magnetization direction. In the magnetization state, the first permanent magnet (31) is in the same magnetization direction as the second permanent magnet (32), and in the demagnetization state, it is opposite to the magnetization direction of the second permanent magnet (32).

2. The series magnetic circuit self-leakage magnetic type variable flux memory motor according to claim 1, characterized in that: The cross-sections of the first permanent magnet (31) and the second permanent magnet (32) are both rectangular, and the magnetization direction is parallel to the length direction of their shorter side. The axes of symmetry of the first permanent magnet (31) and the second permanent magnet (32) coincide.

3. A series magnetic circuit self-leakage type variable flux memory motor according to claim 2, characterized in that: The third permanent magnet (33) and the fan-shaped magnetic barrier (4) are both distributed on the central axis of the adjacent first permanent magnet (31), and their axes of symmetry coincide. The third permanent magnet (33) is unidirectionally magnetized along the magnetization direction, and the magnetization direction of the third permanent magnet (33) is parallel to the length direction of its short side.

4. A series magnetic circuit self-leakage magnetic type variable flux memory motor according to claim 3, characterized in that: The magnetization directions of the adjacent first permanent magnet (31), adjacent second permanent magnet (32), or adjacent third permanent magnet (33) are all opposite.

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