Y-shaped variable flux memory motor rotor structure

Abstract

A Y-shaped variable flux memory motor rotor structure comprises a rotor core, a permanent magnet, a rotating shaft and a magnetic barrier. Eight groups of symmetrical Y-shaped permanent magnet grooves are uniformly distributed in the rotor iron core along the circumference, and the openings of the Y-shaped permanent magnet grooves face the inner side of the rotor and point to the circle center. High-coercivity permanent magnets are embedded into the V-shaped permanent magnet grooves and the bottoms of the linear permanent magnet grooves, and low-coercivity permanent magnets are embedded into the tops of the linear permanent magnet grooves. The permanent magnets in the linear permanent magnet grooves are magnetized in the tangential direction, the strip-shaped permanent magnets on one side of the V-shaped permanent magnets in the V-shaped permanent magnet grooves are magnetized towards the inner side of the rotor in the width direction of the V-shaped permanent magnets, and the strip-shaped permanent magnets on the other side of the V-shaped permanent magnets in the V-shaped permanent magnet grooves are magnetized towards the outer side of the rotor in the width direction of the V-shaped permanent magnets. And the magnetizing directions of the adjacent groups of Y-shaped permanent magnets are opposite. And magnetic isolation barriers are arranged on two sides of each permanent magnet and in adjacent grooves. The motor has three working states, namely a first flux weakening state, a flux increasing state and a second flux weakening state. The motor rotor structure has two flux weakening states and one flux increasing state, so that the motor rotor structure has the advantage of wide speed regulation range and meets the requirements of complex and changeable operation conditions.

Description

Technical Field

[0001] The present invention relates to the field of motor design, and specifically to a rotor structure of a Y-type variable-flux memory motor. Background Art

[0002] In recent years, permanent magnet synchronous motors have attracted the attention and research of experts and scholars at home and abroad with many advantages such as simple structure, high torque / power density, high efficiency, and reliable operation. However, the disadvantage of permanent magnet synchronous motors is that they use rare earth permanent magnets for excitation, and the air-gap magnetic field is basically constant and difficult to adjust, which makes it difficult to expand their speed regulation range. At the same time, under extreme operating conditions such as high current and high temperature, the permanent magnets may encounter a large irreversible demagnetization risk. These defects also limit the large-scale application of this type of motor in the automotive field to a certain extent. Therefore, researching a permanent magnet synchronous motor with high efficiency / torque density, wide speed regulation range, and meeting the requirements of complex and changeable operating conditions of automobiles can better improve the overall performance of automobiles and promote the vigorous development of the electric vehicle industry, which has very important economic value and strategic significance for the automotive industry. Summary of the Invention

[0003] Object of the Invention: To solve the above technical problems, the present invention provides a rotor structure of a Y-type variable-flux memory motor.

[0004] Technical Solution: A rotor structure of a Y-type variable-flux memory motor includes a rotor core, permanent magnets, a rotating shaft, and magnetic barriers. Inside the rotor core, n groups of symmetric Y-type permanent magnet slots are evenly distributed along the circumference. The openings of the Y-type permanent magnet slots face the inner side of the rotor and point to the center of the circle. The Y-type permanent magnet slots include V-type permanent magnet slots at the openings and one-word type permanent magnet slots at the bottoms. The one-word type permanent magnet slots are divided into a bottom and a top by magnetic barriers. High coercivity permanent magnets are embedded inside the V-type permanent magnet slots and at the bottoms (far from the rotating shaft side) of the one-word type permanent magnet slots, and low coercivity permanent magnets are embedded at the tops (close to the rotating shaft side) of the one-word type permanent magnet slots. An upper arc-shaped magnetic barrier is connected to the middle of the high coercivity permanent magnet in the one-word type permanent magnet slot, and a lower arc-shaped magnetic barrier is connected to the V-type permanent magnet slot. The opening directions of the upper and lower arc-shaped magnetic barriers both face the outside of the rotor core. Strip-shaped magnetic isolation barriers are radially arranged between adjacent two groups of Y-type permanent magnet slots.

[0005] The permanent magnets in the one-word type permanent magnet slots are tangentially magnetized. The V-type permanent magnets in the V-type permanent magnet slots are composed of strip-shaped permanent magnets on both sides. One side of the strip-shaped permanent magnet is magnetized towards the inner side of the rotor along its width direction, and the other side of the strip-shaped permanent magnet is magnetized towards the outer side of the rotor along its width direction. The magnetization directions of adjacent groups of Y-type permanent magnets are opposite. Magnetic isolation barriers are arranged on both sides and adjacent slots of each permanent magnet.

[0006] This motor has three working states, namely the first field weakening state, the second field weakening state, and the field strengthening state.

[0007] The motor in the first weak magnetic state is in no-load condition, and there is a deliberately set magnetic leakage bridge. The magnetic flux generated by the high coercivity permanent magnet not only flows into the stator to form effective magnetic flux, but also enters the adjacent magnetic poles through the magnetic leakage bridge to become leakage magnetic flux. The existence of the first weak magnetic state lays a foundation for magnetic flux regulation for the second weak magnetic state and the flux-weakening state.

[0008] The motor in the second weak magnetic state is in high-speed operation. When the motor operates at high speed, it usually requires less torque. Therefore, it is necessary to reduce the main magnetic flux and thus the torque. While maintaining the leakage magnetic flux formed in the first weak magnetic state, the magnetization direction of the low coercivity permanent magnet changes, forming a magnetic leakage loop with the high coercivity permanent magnet in the straight-shaped permanent magnet slot, and at the same time forming another magnetic leakage loop with the V-shaped permanent magnet. The combined action of the leakage magnetic flux and the two magnetic leakage loops meets the requirements of weak magnetic field.

[0009] The motor in the flux-weakening state is under heavy load conditions. When under heavy load, the demand for torque increases. At this time, the torque is increased by inputting armature current, and it is necessary to reduce magnetic leakage to increase the main magnetic flux, thereby forming more effective magnetic chains. At this time, most of the armature current is converted into q-axis current to form q-axis magnetic flux. When a large amount of q-axis magnetic flux flows through the q-axis magnetic leakage bridge, the magnetic leakage bridge will become magnetically saturated, which can block the magnetic leakage channel and reduce the leakage magnetic flux. At this time, the leakage magnetic flux in the first weak magnetic state will become flux-weakening magnetic flux. At the same time, the magnetization direction of the low coercivity permanent magnet changes, forming a flux-weakening loop with the V-shaped magnet. The combination of the flux-weakening magnetic flux and the flux-weakening loop is used to increase the output torque to meet the large torque required under heavy load.

[0010] In the first weak magnetic state, the magnetization direction of the low coercivity permanent magnet in the straight-shaped permanent magnet slot is the same as that of the high coercivity permanent magnet; in the second weak magnetic state, the low coercivity permanent magnet and the high coercivity permanent magnet in the straight-shaped permanent magnet slot change from the original co-directional magnetization to reverse magnetization; in the flux-weakening state, the low coercivity permanent magnet and the high coercivity permanent magnet in the straight-shaped permanent magnet slot change from reverse magnetization in the second weak magnetic state to co-directional magnetization.

[0011] Preferably, the rotor core is made of high permeability silicon steel sheet material.

[0012] Preferably, the high coercivity permanent magnet is made of rare earth neodymium iron boron material.

[0013] Preferably, the low coercivity permanent magnet is made of alnico material.

[0014] Preferably, the magnetic barrier is made of epoxy resin-based composite material.

[0015] The present invention has the following beneficial effects:

[0016] The motor rotor structure of the present invention can act in different working states according to working conditions. For example, it can work in the flux-weakening state under low-speed and high-torque working conditions and can achieve two-stage flux-weakening states under high-speed working conditions. Therefore, it has the advantages of low-speed high torque and a wide speed regulation range at high speed, meeting the requirements of complex and variable operating conditions of automobiles.

[0017] In this motor rotor structure, adjacent groups of permanent magnet structures have a magnetic concentration effect, so the torque density of the motor can be improved.

[0018] When the motor is in the flux-weakening state, the series circuit formed by two bar-shaped permanent magnets in the lower V-shaped high-coercivity permanent magnet is connected in parallel with the series circuit formed by the straight-shaped permanent magnet to form a series-parallel magnetic circuit, which helps to increase the main magnetic flux and torque density of the motor, thereby improving the output power and efficiency of the motor. Description of the Drawings

[0019] Att Figure 1 is a schematic diagram of the rotor structure of the permanent magnet synchronous motor proposed by the present invention.

[0020] Att Figure 2 is a schematic diagram of the rotor slot structure.

[0021] Att Figure 3 is a schematic diagram of the magnetization direction of the permanent magnet.

[0022] Att Figure 4 is a magnetic flux distribution diagram when the motor is in the first flux-weakening state.

[0023] Att Figure 5 is a magnetic flux distribution diagram when the motor is in the flux-weakening state.

[0024] Att Figure 6 is a magnetic flux distribution diagram when the motor is in the second flux-weakening state.

[0025] Symbol Explanation: 1 Rotor core, 2 Permanent magnet, 3 Rotating shaft, 4 Magnetic barrier, 5 Y-shaped permanent magnet slot, 6 Magnetic bridge, 7 Leakage magnetic flux, 8 Effective magnetic flux, 9 Leakage magnetic circuit formed between the high- and low-coercivity permanent magnets in the straight-shaped slot, 10 Leakage magnetic circuit formed between the low-coercivity permanent magnet in the straight-shaped slot and the V-shaped permanent magnet, 11 Flux-increasing magnetic flux, 12 Flux-increasing circuit formed between the high- and low-coercivity permanent magnets in the straight-shaped slot, 13 Flux-increasing circuit formed between the low-coercivity permanent magnet in the straight-shaped slot and the V-shaped permanent magnet.

[0026] 2-1 is the permanent magnet in the straight-shaped permanent magnet slot. 2-2 is the V-shaped permanent magnet in the V-shaped permanent magnet slot, 2-3 is the bar-shaped permanent magnet on one side of the V-shaped permanent magnet, 2-4 is the bar-shaped permanent magnet on the other side of the V-shaped permanent magnet, 2-5 is the high-coercivity permanent magnet in the straight-shaped permanent magnet slot, 2-6 is the low-coercivity permanent magnet in the straight-shaped permanent magnet slot, 2-7 is the adjacent group of Y-shaped permanent magnets.

[0027] 4-1 is the upper dendritic magnetic barrier, 4-2 is the lower dendritic magnetic barrier, and 4-3 is the strip-shaped magnetic isolation barrier.

[0028] 5-1 is the V-shaped permanent magnet slot, and 5-2 is the linear permanent magnet slot. Specific implementation manner

[0029] As Figures 1-3 As shown, a rotor structure of a Y-shaped variable-flux memory motor includes a rotor core 1, permanent magnets 2, a rotating shaft 3, and magnetic barriers 4. Inside the rotor core 1, 8 groups of symmetric Y-shaped permanent magnet slots 5 are evenly distributed along the circumference. The openings of the Y-shaped permanent magnet slots 5 face the inner side of the rotor and point to the center of the circle. The Y-shaped permanent magnet slot 5 includes a V-shaped permanent magnet slot 5-1 at the opening and a linear permanent magnet slot 5-2 at the bottom. The linear permanent magnet slot 5-2 is divided into a bottom and a top by the magnetic barrier 4; high coercivity permanent magnets 2-2 and 2-5 are embedded inside the V-shaped permanent magnet slot 5-1 and at the bottom (far from the rotating shaft 3 side) of the linear permanent magnet slot 5-2, and low coercivity permanent magnets 2-6 are embedded at the top (close to the rotating shaft 3 side) of the linear permanent magnet slot 5-2. In the middle of the high coercivity permanent magnet 2-5 in the linear permanent magnet slot 5-2, an upper arc-shaped magnetic barrier 4-1 is connected. The V-shaped permanent magnet slot 5-1 is connected with a lower arc-shaped magnetic barrier 4-2. The opening directions of the upper and lower arc-shaped magnetic barriers 4-1 and 4-2 both face the outer side of the rotor core 1. Strip-shaped magnetic isolation barriers 4-3 are radially arranged between adjacent groups of Y-shaped permanent magnet slots 5.

[0030] As Figure 3 As shown, the permanent magnet 2-1 in the linear permanent magnet slot 5-2 is tangentially magnetized. For the V-shaped permanent magnet 2-2 in the V-shaped permanent magnet slot 5-1, one side of the strip-shaped permanent magnet 2-3 is magnetized towards the inner side of the rotor along its width direction, and the other side of the strip-shaped permanent magnet 2-4 is magnetized towards the outer side of the rotor along its width direction. The magnetization directions of adjacent groups of Y-shaped permanent magnets 2-7 are opposite. Magnetic barriers 4 are arranged on both sides and adjacent slots of each permanent magnet 2.

[0031] Figure 4 is the flux distribution when the motor is in the first weak magnetic state. At this time, the motor is in the no-load state, and there is a deliberately set magnetic leakage bridge 6. The flux generated by the high coercivity permanent magnet 2-5 not only flows into the stator to form the effective flux 8, but also will enter the adjacent magnetic poles through the magnetic leakage bridge 6 to become the leakage flux 7. The existence of the first weak magnetic state lays the foundation for magnetic field regulation in the second weak magnetic state and the flux-weakening state.

[0032] Figure 5The magnetic flux distribution in the second weak magnetic state. The second weak magnetic state means that the motor is in a high-speed operation state. When the motor operates at high speed, it usually requires a smaller torque. Therefore, it is necessary to reduce the main magnetic flux and thus the torque. While maintaining the leakage magnetic flux 7 formed in the first weak magnetic state, the magnetization direction of the low coercivity permanent magnet 2-6 changes, forming a leakage magnetic circuit 9 with the high coercivity permanent magnet 2-5 in the straight permanent magnet slot 5-2, and at the same time forming another leakage magnetic circuit 10 with the V-shaped permanent magnet 2-2. The leakage magnetic flux 7, together with the leakage magnetic circuits 9 and 10, acts together to meet the weak magnetic requirement.

[0033] Figure 6 The magnetic flux distribution when the motor is in the flux-weakening state. At this time, the motor is in a heavy-load working condition. When in heavy load, the demand for torque increases. At this time, the torque is increased by inputting the armature current, and it is necessary to reduce the leakage magnetic flux to increase the main magnetic flux, thereby forming more effective magnetic chains. At this time, most of the armature current is converted into the q-axis current to form the q-axis magnetic flux. When a large amount of q-axis magnetic flux flows through the q-axis leakage magnetic bridge 6, the q-axis leakage magnetic bridge 6 will be magnetically saturated, which can block the leakage magnetic channel and reduce the leakage magnetic flux 7. At this time Figure 4 the leakage magnetic flux 7 in it will become the flux-increasing magnetic flux 11. At the same time, the magnetization direction of the low coercivity permanent magnet 2-6 changes, the leakage magnetic circuit 9 in the second weak magnetic state becomes the flux-increasing circuit 12, and the leakage magnetic circuit 10 becomes the flux-increasing circuit 13. The flux-increasing magnetic flux 11 combines with the flux-increasing circuits 12 and 13 to increase the main magnetic flux, thereby increasing the output torque to meet the large torque required during heavy load.

[0034] In the first weak magnetic state, the magnetization directions of the low coercivity permanent magnet 2-6 and the high coercivity permanent magnet 2-5 in the straight permanent magnet slot 5-2 are the same; in the second weak magnetic state, the low coercivity permanent magnet 2-6 and the high coercivity permanent magnet 2-5 in the straight permanent magnet slot 5-2 change from the original co-directional magnetization to reverse magnetization; in the flux-increasing state, the low coercivity permanent magnet 2-6 and the high coercivity permanent magnet 2-5 in the straight permanent magnet slot 5-2 change from the reverse magnetization in the second weak magnetic state to co-directional magnetization.

[0035] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the above specific embodiments, and the protection scope of the present invention also includes various deformations or modifications made by those skilled in the art within the scope of the claims.

Claims

1. A Y-type variable flux memory motor rotor structure, characterized in that: The invention comprises a rotor core (1), a permanent magnet (2), a rotating shaft (3) and a magnetic barrier (4); n groups of symmetrical Y-shaped permanent magnet slots (5) are evenly distributed along the circumference inside the rotor core (1); the opening of the Y-shaped permanent magnet slot (5) faces the inside of the rotor and points to the center of the circle; the Y-shaped permanent magnet slot (5) comprises a V-shaped permanent magnet slot (5-1) at the opening and a straight-line permanent magnet slot (5-2) at the bottom; the straight-line permanent magnet slot (5-2) is divided into a bottom and a top by a magnetic barrier; inside the V-shaped permanent magnet slot (5-1) and the straight-line permanent magnet slot (5-2) A high coercive force permanent magnet is embedded in the bottom of the rotor, and a low coercive force permanent magnet (2-6) is embedded in the top of the I-shaped permanent magnet slot (5-2); an upper arc-shaped magnetic barrier (4-1) is connected to the middle of the high coercive force permanent magnet (2-5) in the I-shaped permanent magnet slot (5-2), and a lower arc-shaped magnetic barrier (4-2) is connected to the V-shaped permanent magnet slot (5-1), and the opening directions of the upper arc-shaped magnetic barrier (4-1) and the lower arc-shaped magnetic barrier (4-2) are both toward the outside of the rotor core (1); and a strip-shaped magnetic isolation magnetic barrier (4-3) is radially arranged between two adjacent groups of Y-shaped permanent magnet slots (5).

2. According to claim 1, a Y-type variable flux memory motor rotor structure is characterized in that: The permanent magnet (2-1) in the straight permanent magnet slot (5-2) is magnetized tangentially; the V-shaped permanent magnet (2-2) in the V-shaped permanent magnet slot (5-1) is composed of bar-shaped permanent magnets on two sides, the bar-shaped permanent magnet (2-3) on one side is magnetized along its width direction toward the inside of the rotor, and the bar-shaped permanent magnet (2-4) on the other side is magnetized along its width direction toward the outside of the rotor; adjacent groups of Y-shaped permanent magnets (2-7) are magnetized in opposite directions.

3. The Y-type variable flux memory motor rotor structure according to claim 1, characterized in that: The motor has a first weak magnetic state, a second weak magnetic state and a magnetization state; in the first weak magnetic state, the motor is in a no-load state; in the second weak magnetic state, the motor is in a high-speed operation state; in the magnetization state, the motor is in a heavy-load condition.

4. A Y-type variable flux memory motor rotor structure according to claim 3, characterized in that: In the motor with the rotor structure, in a first weak magnetic state, a magnetic barrier is arranged at the bottom of the straight permanent magnet slot (5-2) in a direction away from the rotating shaft (3), and the high coercive force permanent magnet (2-5) and the magnetic barrier form a leakage magnetic bridge (6). The magnetic flux generated by the high coercive force permanent magnet (2-5) not only flows into the stator to form an effective magnetic flux (8), but also passes through the leakage magnetic bridge (6) and enters the adjacent magnetic pole to become leakage magnetic flux (7).

5. A Y-type variable flux memory motor rotor structure according to claim 4, characterized in that: The motor of the rotor structure is in a second weak magnetic state, which maintains the leakage magnetic flux (7) formed in the first weak magnetic state, while the magnetization direction of the low coercive force permanent magnet (2-6) is changed to form a leakage magnetic circuit (9) with the high coercive force permanent magnet (2-5) in the I-shaped permanent magnet slot (5-2), and at the same time forms another leakage magnetic circuit (10) with the V-shaped permanent magnet (2-2).

6. A Y-type variable flux memory motor rotor structure according to claim 5, characterized in that: The motor with the rotor structure increases torque by inputting armature current in the magnetizing state, and the armature current is converted into q-axis current to form q-axis magnetic flux. When the q-axis magnetic flux flows through the q-axis leakage magnetic bridge (6), the leakage magnetic bridge (6) is magnetically saturated, and the leakage magnetic flux (7) is converted into the magnetizing flux (11). At the same time, the magnetizing direction of the low coercive force permanent magnet (2-6) is changed, and the leakage magnetic circuit in the second weak magnetic state is converted into the magnetizing circuit.

7. The Y-type variable flux memory motor rotor structure according to claim 3, characterized in that: In the first weak magnetic state, the magnetization direction of the low coercive force permanent magnet (2-6) in the straight permanent magnet slot (5-2) is the same as the magnetization direction of the high coercive force permanent magnet (2-5); in the second weak magnetic state, the low coercive force permanent magnet (2-6) and the high coercive force permanent magnet (2-5) in the straight permanent magnet slot (5-2) are magnetized in opposite directions instead of in the same direction; In the magnetization state, the low coercive force permanent magnet (2-6) and the high coercive force permanent magnet (2-5) in the straight permanent magnet slot (5-2) are magnetized in the same direction instead of being magnetized in the opposite direction in the second weak magnetic state.

8. The Y-type variable flux memory motor rotor structure according to claim 1, characterized in that: The rotor core is made of high magnetic permeability silicon steel sheet material.

9. A Y-type variable flux memory motor rotor structure according to claim 1, characterized in that: The high coercive force permanent magnet is made of rare earth neodymium iron boron material.

10. A Y-type variable flux memory motor rotor structure according to claim 1, characterized in that: The low coercive force permanent magnet is made of Al-Ni-Co material.

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