A magnetic pole complementary hybrid permanent magnet memory motor

Abstract

This invention belongs to the field of motor technology and discloses a magnetic pole complementary hybrid permanent magnet memory motor, including a hybrid permanent magnet rotor. The hybrid permanent magnet rotor includes a rotor core, a first permanent magnet, a second permanent magnet, a third permanent magnet, a fourth permanent magnet, and U-shaped magnetic barriers with outward openings evenly distributed around the rotor core. The third and fourth permanent magnets are symmetrically arranged on both sides of the U-shaped magnetic barriers, and the first and second permanent magnets are embedded in a straight line at the bottom of the U-shaped magnetic barriers. The permanent magnets embedded on both sides of each U-shaped magnetic barrier have the same coercivity, but different coercivity from the permanent magnet embedded at the bottom. The permanent magnets embedded at the bottom and sides of adjacent magnetic barriers have different coercivity. Permanent magnets with different coercivity levels in adjacent magnetic poles form a "complementary" arrangement. This invention further expands the rotor design space through a complementary magnetic pole structure, combining high torque density and strong magnetic stability.

Description

Technical Field

[0001] This invention belongs to the field of motor technology, specifically relating to a magnetic pole complementary hybrid permanent magnet memory motor. Background Technology

[0002] Permanent magnet synchronous motors (PMSMs) are widely used in new energy vehicles, industrial automation, aerospace, and home appliances due to their high efficiency, high torque density, and excellent dynamic characteristics.

[0003] To improve power density and enhance load capacity, traditional permanent magnet synchronous motors (PMSMs) often employ strong rare-earth permanent magnets (such as neodymium iron boron). However, due to the inherent high coercivity of neodymium iron boron permanent magnets, the air gap flux is difficult to adjust, limiting the speed range of the motor. To achieve wide speed range operation of PMSMs, a common method is to introduce a negative direct-axis current component into the stator windings. However, this method increases stator copper losses, reduces motor system efficiency, and may lead to irreversible demagnetization of the permanent magnets, inverter failures, and damage to the inverter's power devices. Therefore, achieving efficient air gap magnetic field adjustment and expanding the speed range of PMSMs has become a key issue restricting their application.

[0004] The concept of the Variable Flux Memory Machine (VFMM) was first proposed by German scholar Ostowicz in 2001. This type of memory motor can achieve online adjustment of the air gap magnetic field by applying short-time pulse currents to the stator windings to change the magnetization intensity of low-coercivity permanent magnets (such as AlNiCo), enabling switching between multiple magnetization states with almost no excitation losses. It holds promise for high-efficiency operation across a wide speed range. However, single low-coercivity permanent magnet memory motors suffer from low torque density and are prone to accidental demagnetization due to armature reaction. Therefore, many scholars both domestically and internationally have proposed hybrid permanent magnet memory motors. These motors are characterized by simultaneously incorporating both high-coercivity and low-coercivity permanent magnets on the rotor core.

[0005] Hybrid permanent magnet memory motors can be divided into parallel magnetic circuit type and series magnetic circuit type. Parallel magnetic circuit type memory motors have a wide magnetic adjustment range, but the armature reaction during load operation can easily cause unexpected demagnetization of the low coercivity permanent magnets. Series magnetic circuit type memory motors have high torque density and stable operating point of the low coercivity permanent magnets, but the magnetic adjustment range is limited. Traditional permanent magnet synchronous motors are mostly designed with positive salient polarity to make better use of reluctance torque, but there is a relatively serious cross-coupling phenomenon between the permanent magnet magnetic field and the armature magnetic field.

[0006] To address this issue, a magnetic pole complementary hybrid permanent magnet memory motor is provided to solve the serious demagnetization problem caused by cross-coupling between high-coercivity permanent magnets and low-coercivity permanent magnets, thereby improving the stability of the operating point of the low-coercivity permanent magnets. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide a magnetic pole complementary hybrid permanent magnet memory motor, which solves the serious demagnetization problem caused by cross-coupling between high-coercivity permanent magnets and low-coercivity permanent magnets in existing technologies, and improves the stability of the operating point of low-coercivity permanent magnets.

[0008] The objective of this invention can be achieved through the following technical solutions:

[0009] A magnetic pole complementary hybrid permanent magnet memory motor includes a hybrid permanent magnet rotor, which is composed of a rotor core, a first permanent magnet, a third permanent magnet, a second permanent magnet, a fourth permanent magnet, and a U-shaped magnetic barrier. A first hybrid permanent magnet module includes the first permanent magnet, the third permanent magnet, and the U-shaped magnetic barrier; the first permanent magnet is embedded at the bottom of the U-shaped magnetic barrier, and the third permanent magnet is embedded on both sides of the U-shaped magnetic barrier. A second hybrid permanent magnet module includes the second permanent magnet, the fourth permanent magnet, and the U-shaped magnetic barrier; the second permanent magnet is embedded at the bottom of the U-shaped magnetic barrier, and the fourth permanent magnet is embedded on both sides of the U-shaped magnetic barrier. U-shaped slots are evenly distributed radially outward from the rotor core, and the U-shaped magnetic barrier is fixedly connected within the U-shaped slots. The first and second hybrid permanent magnet modules are arranged adjacent to each other, and are alternately distributed within the U-shaped slots on the rotor core.

[0010] Furthermore, the U-shaped magnetic barrier opening is positioned outwards.

[0011] Furthermore, the second and fourth permanent magnets are neodymium iron boron permanent magnets; the first and third permanent magnets are aluminum nickel cobalt permanent magnets.

[0012] Furthermore, the first permanent magnet and the third permanent magnet are connected in parallel on the magnetic circuit; the second permanent magnet and the fourth permanent magnet are connected in parallel on the magnetic circuit.

[0013] Furthermore, the first permanent magnet and the second permanent magnet are connected in series in the magnetic circuit.

[0014] Furthermore, the first permanent magnet and the third permanent magnet constitute the N pole of the permanent magnet pole; the second permanent magnet and the fourth permanent magnet constitute the S pole of the permanent magnet pole.

[0015] Furthermore, the first and second permanent magnets are magnetized radially around the rotor core, while the third and fourth permanent magnets are magnetized tangentially perpendicular to both sides of the U-shaped magnetic barrier.

[0016] Furthermore, the hybrid permanent magnet rotor is disposed on the inner side of the stator; the stator includes a stator yoke, stator teeth and stator slots; the stator teeth are disposed between the stator yoke and the hybrid permanent magnet rotor and are fixedly connected to the stator yoke, and the stator slots are formed between adjacent stator teeth; the armature winding is wound on the stator teeth.

[0017] Furthermore, an air gap is left between the inner radial side of the stator and the outer radial side of the hybrid permanent magnet rotor.

[0018] Furthermore, a non-magnetic shaft is provided on the inner side of the rotor core along the axial direction.

[0019] The beneficial effects of this invention are:

[0020] 1. The first permanent magnet and the second permanent magnet arranged in adjacent U-shaped magnetic barriers of the present invention form a series magnetic circuit, and the third permanent magnet and the fourth permanent magnet form a series magnetic circuit. The V-shaped design of the permanent magnets with different coercivity in each U-shaped magnetic barrier forms a magnetic focusing effect, which helps to improve the stability of the working point of the low coercivity permanent magnet and enhance the magnetic stabilization effect.

[0021] 2. The present invention sets up U-shaped magnetic barriers evenly distributed around the rotor core in the circumferential direction, which effectively reduces the problem of cross-coupling demagnetization of low-coupling permanent magnets by high-coercivity permanent magnets. The embedded arrangement of U-shaped magnetic barriers, third permanent magnets and fourth permanent magnets reduces the cross-axis inductance of the motor, improves the anti-salient pole characteristics of the motor, increases the magnetic adjustment range and inverter voltage utilization.

[0022] 3. This invention uses short-time current pulses for magnetization, with almost no magnetization copper loss. The low coercivity permanent magnet can be repeatedly magnetized online. The magnetization control is similar to traditional vector control and is easy to implement. Placing the first permanent magnet on the shortest path of the direct axis effectively reduces the required magnetization current.

[0023] 4. The complementary magnetic pole structure of the present invention improves the design freedom of the permanent magnet rotor of the motor and the utilization rate of permanent magnets, and effectively reduces the amount of permanent magnets used. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the cross-sectional structure of the motor according to an embodiment of the present invention;

[0026] Figure 2 This is a magnetic field distribution diagram of the motor in the magnetized state according to an embodiment of the present invention;

[0027] Figure 3 This is a magnetic field distribution diagram of the motor in the demagnetized state according to an embodiment of the present invention. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] In the description of this invention, it should be understood that the terms "opening", "upper", "lower", "thickness", "top", "middle", "length", "inner", "around", etc., which indicate orientation or positional relationship, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the components or elements referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting this invention.

[0030] like Figure 1 As shown, one embodiment of the present invention provides a magnetic pole complementary hybrid permanent magnet memory motor, including a hybrid permanent magnet rotor 3. The hybrid permanent magnet rotor 3 is composed of a rotor core 31, a first permanent magnet 32, a third permanent magnet 33, a second permanent magnet 34, a fourth permanent magnet 35, and a U-shaped magnetic barrier 36. The first hybrid permanent magnet module includes the first permanent magnet 32, the third permanent magnet 33, and the U-shaped magnetic barrier 36; the first permanent magnet 32 ​​is embedded in the bottom of the U-shaped magnetic barrier 36, and the third permanent magnet 33 is embedded in both sides of the U-shaped magnetic barrier 36. The second hybrid permanent magnet module includes the second permanent magnet 34, the fourth permanent magnet 35, and the U-shaped magnetic barrier 36; the second permanent magnet 34 is embedded in the bottom of the U-shaped magnetic barrier 36, and the fourth permanent magnet 35 is embedded in both sides of the U-shaped magnetic barrier 36. U-shaped slots are evenly distributed radially on the outer side of the rotor core 31, and the U-shaped magnetic barrier 36 is fixedly connected in the U-shaped slots. The first hybrid permanent magnet module and the second hybrid permanent magnet module are arranged adjacent to each other, and the first hybrid permanent magnet module and the second hybrid permanent magnet module are alternately distributed in the U-shaped groove on the rotor core 31.

[0031] The U-shaped magnetic barrier 36 has an outward opening, which can reduce magnetic leakage.

[0032] The second permanent magnet 34 and the fourth permanent magnet 35 are neodymium iron boron permanent magnets, while the first permanent magnet 32 ​​and the third permanent magnet 33 are AlNiCo permanent magnets. The first permanent magnet 32 ​​and the third permanent magnet 33 are connected in parallel in the magnetic circuit, as are the second permanent magnet 34 and the fourth permanent magnet 35. The first permanent magnet 32 ​​and the second permanent magnet 34 are connected in series in the magnetic circuit. The first permanent magnet 32 ​​and the third permanent magnet 33 form the N pole of the permanent magnet poles, while the second permanent magnet 34 and the fourth permanent magnet 35 form the S pole of the permanent magnet poles. The first permanent magnet 32 ​​and the second permanent magnet 34 are magnetized radially around the rotor core 31, while the third permanent magnet 33 and the fourth permanent magnet 35 are magnetized tangentially to both sides of the U-shaped magnetic barrier 36.

[0033] The permanent magnets embedded symmetrically in a V-shape on both sides of each U-shaped magnetic barrier 36 have the same coercivity, while the permanent magnets embedded at the bottom and sides have different coercivity. The straight-line permanent magnets embedded at the bottom of adjacent U-shaped magnetic barriers 36 have different coercivity, as do the V-shaped permanent magnets embedded on both sides of adjacent U-shaped magnetic barriers 36. Permanent magnets with different coercivity levels in adjacent magnetic poles form a "complementary" arrangement. This complementary magnetic pole structure increases the design freedom of the permanent magnet rotor and the utilization rate of permanent magnets, effectively reducing the amount of permanent magnets used.

[0034] The first permanent magnet 32 ​​and the second permanent magnet 34 set in adjacent U-shaped magnetic barriers 36 form a series magnetic circuit, and the third permanent magnet 33 and the fourth permanent magnet 35 form a series magnetic circuit. The V-shaped design of permanent magnets with different coercivity in each U-shaped magnetic barrier 36 forms a magnetic focusing effect, which helps to improve the stability of the working point of the low coercivity permanent magnet and enhance the magnetic stabilization effect.

[0035] The U-shaped magnetic barriers 36, which are evenly distributed around the rotor core 31, effectively reduce the demagnetization problem caused by the cross-coupling of high-coercivity permanent magnets to low-coercivity permanent magnets. The embedded arrangement of the U-shaped magnetic barriers 36, the third permanent magnet 33, and the fourth permanent magnet 35 reduces the cross-axis inductance of the motor, improves the anti-salient pole characteristics of the motor, and increases the magnetic adjustment range and inverter voltage utilization.

[0036] The hybrid permanent magnet rotor 3 is disposed inside the stator 1. The stator 1 includes a stator yoke 11, stator teeth 12, and stator slots 13. The stator teeth 12 are disposed between the stator yoke 11 and the hybrid permanent magnet rotor 3, and are fixedly connected to the stator yoke 11. A cavity, i.e., a stator slot 13, is formed between adjacent stator teeth 12 for placing the three-phase armature winding 2 wound on the stator teeth 12.

[0037] An air gap is left between the inner radial side of the stator 1 and the outer radial side of the hybrid permanent magnet rotor 3.

[0038] A non-magnetic shaft 4 is provided on the inner side of the rotor core 31 along the axial direction.

[0039] The operating principle of the magnetic pole complementary hybrid permanent magnet memory motor disclosed in this invention is as follows:

[0040] In the magnetized state, the distribution of the motor's magnetic field lines is as follows: Figure 2 As shown; the first permanent magnet 32 ​​and the third permanent magnet 33 constitute the north pole of the motor, and the second permanent magnet 34 and the fourth permanent magnet 35 together constitute the south pole of the motor; the permanent magnet flux starts from the north pole of the first permanent magnet 32 ​​and the third permanent magnet 33, first reaches the stator tooth 12, and then passes through the stator yoke 11, passes through the second permanent magnet 34 and the fourth permanent magnet 35 respectively, and returns to the south pole of the first permanent magnet 32 ​​and the third permanent magnet 33.

[0041] The first permanent magnet 32 ​​and the third permanent magnet 33 can be magnetized bidirectionally, and their magnetization state is easy to change. They can be magnetized or demagnetized by applying an instantaneous direct-axis current, thereby adjusting the air gap magnetic flux density of the motor.

[0042] Under weak magnetic field conditions, the distribution of the motor's magnetic field lines is as follows: Figure 3 As shown, a portion of the permanent magnet flux originates from the north pole of the third permanent magnet 33, passes through the stator tooth 12 and the stator yoke 11, passes through the second permanent magnet 34, and returns to the south pole of the third permanent magnet 33; another portion of the permanent magnet flux originates from the north poles of the third permanent magnet 33 and the second permanent magnet 34, passes through the first permanent magnet 32 ​​and the fourth permanent magnet 35, and returns directly to its south pole; at this time, the magnetic circuits of the first permanent magnet 32 ​​and the second permanent magnet 34 are in parallel.

[0043] At the same time, a three-phase alternating current with the same speed as the hybrid permanent magnet rotor 3 is passed into the armature winding 2 of the motor. The rotating magnetic fields formed by the stator and rotor interact with each other, thereby realizing the electromechanical energy conversion.

[0044] This invention utilizes short-duration current pulses for magnetization, resulting in almost no magnetization copper loss. The low-coercivity permanent magnet can be repeatedly magnetized online. The magnetization control is similar to traditional vector control and is easy to implement. Placing the first permanent magnet on the shortest path of the direct axis effectively reduces the required magnetization current.

[0045] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0046] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the present invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A magnetic pole complementary hybrid permanent magnet memory motor, comprising a hybrid permanent magnet rotor (3), characterized in that, The hybrid permanent magnet rotor (3) is composed of a rotor core (31), a first permanent magnet (32), a third permanent magnet (33), a second permanent magnet (34), a fourth permanent magnet (35), and a U-shaped magnetic barrier (36); The first hybrid permanent magnet module includes a first permanent magnet (32), a third permanent magnet (33), and a U-shaped magnetic barrier (36); the first permanent magnet (32) is embedded in the bottom of the U-shaped magnetic barrier (36), and the third permanent magnet (33) is embedded in both sides of the U-shaped magnetic barrier (36); The second hybrid permanent magnet module includes the second permanent magnet (34), the fourth permanent magnet (35), and the U-shaped magnetic barrier (36); the second permanent magnet (34) is embedded in the bottom of the U-shaped magnetic barrier (36), and the fourth permanent magnet (35) is embedded in both sides of the U-shaped magnetic barrier (36); The rotor core (31) has U-shaped grooves evenly distributed on the radial outer side, and the U-shaped magnetic barrier (36) is fixedly connected in the U-shaped groove; The coercivity of the permanent magnets embedded in the V-shape on both sides of each U-shaped magnetic barrier (36) is the same, while the coercivity of the permanent magnets embedded at the bottom and on both sides is different. The coercivity of the I-shaped permanent magnets embedded at the bottom of adjacent U-shaped magnetic barriers (36) is different, and the coercivity of the permanent magnets embedded in the V-shape on both sides of adjacent U-shaped magnetic barriers (36) is different. The first hybrid permanent magnet module and the second hybrid permanent magnet module are alternately distributed in the U-shaped slots on the rotor core (31), and the permanent magnets with different coercivity levels of adjacent magnetic poles form a "complementary" arrangement. The first hybrid permanent magnet module and the second hybrid permanent magnet module are arranged adjacent to each other, and the first hybrid permanent magnet module and the second hybrid permanent magnet module are alternately distributed in the U-shaped groove on the rotor core (31).

2. The magnetic pole complementary hybrid permanent magnet memory motor according to claim 1, characterized in that, The U-shaped magnetic barrier (36) has an opening facing outwards.

3. The magnetic pole complementary hybrid permanent magnet memory motor according to claim 1, characterized in that, The second permanent magnet (34) and the fourth permanent magnet (35) are neodymium iron boron permanent magnets; the first permanent magnet (32) and the third permanent magnet (33) are aluminum nickel cobalt permanent magnets.

4. The magnetic pole complementary hybrid permanent magnet memory motor according to claim 1, characterized in that, The first permanent magnet (32) and the third permanent magnet (33) are connected in parallel on the magnetic circuit; the second permanent magnet (34) and the fourth permanent magnet (35) are connected in parallel on the magnetic circuit.

5. The magnetic pole complementary hybrid permanent magnet memory motor according to claim 1, characterized in that, The first permanent magnet (32) and the second permanent magnet (34) are connected in series in the magnetic circuit.

6. The magnetic pole complementary hybrid permanent magnet memory motor according to claim 1, characterized in that, The first permanent magnet (32) and the third permanent magnet (33) constitute the N pole of the permanent magnet pole; the second permanent magnet (34) and the fourth permanent magnet (35) constitute the S pole of the permanent magnet pole.

7. The magnetic pole complementary hybrid permanent magnet memory motor according to claim 1, characterized in that, The first permanent magnet (32) and the second permanent magnet (34) are magnetized radially around the rotor core (31), while the third permanent magnet (33) and the fourth permanent magnet (35) are magnetized in a tangential direction perpendicular to both sides of the U-shaped magnetic barrier (36).

8. The magnetic pole complementary hybrid permanent magnet memory motor according to claim 1, characterized in that, The hybrid permanent magnet rotor (3) is disposed inside the stator (1); the stator (1) includes a stator yoke (11), stator teeth (12) and stator slots (13); The stator teeth (12) are disposed between the stator yoke (11) and the hybrid permanent magnet rotor (3) and are fixedly connected to the stator yoke (11). The stator slots (13) are formed between adjacent stator teeth (12). The armature winding (2) is wound on the stator teeth (12).

9. The magnetic pole complementary hybrid permanent magnet memory motor according to claim 8, characterized in that, An air gap is left between the inner radial side of the stator (1) and the outer radial side of the hybrid permanent magnet rotor (3).

10. The magnetic pole complementary hybrid permanent magnet memory motor according to claim 1, characterized in that, The inner side of the rotor core (31) is provided with a non-magnetic shaft (4) along the axial direction.

Images