Centrifugal variable flux permanent magnet motor and method for increasing and decreasing permanent magnet leakage flux of the motor

Abstract

The application discloses a centrifugal variable-flux permanent magnet motor and a method for increasing and decreasing leakage of permanent magnet of the motor, and relates to the technical field of motors. The motor comprises a stator mechanism and a rotor mechanism. The rotor mechanism comprises a magnetic conducting block, a spring, a non-magnetic conducting block, a permanent magnet, a non-magnetic body and a rotor core. A plurality of permanent magnet pairs are arranged in the rotor core. Each permanent magnet pair comprises six permanent magnets. The six permanent magnets are arranged in a U-shaped part and a I-shaped part in an adjacent manner. The two ends of the U-shaped part of the six permanent magnets are provided with grooves. The magnetic conducting blocks are slidably arranged in the grooves. The magnetic conducting blocks of the motor rotor are affected by centrifugal force and spring tension. The positions of the magnetic conducting blocks can be changed at different rotating speeds. The leakage path reluctance of the permanent magnet flux can be reduced or increased. The permanent magnet field in the air gap can be reduced or increased. The motor torque density and the weak magnetic field expansion speed capacity are improved. The overall structure of the motor is not complex, and the motor is convenient to install and use.

Description

Technical Field

[0001] This invention relates to the field of motor technology, and in particular to a centrifugal variable flux permanent magnet motor and a method for increasing or decreasing the leakage flux of the permanent magnet in the motor. Background Technology

[0002] Currently, permanent magnet synchronous motors use high-performance permanent magnet materials to provide the excitation magnetic field, eliminating the need for excitation current on the stator side. The motor efficiency and power factor are higher than those of asynchronous motors. However, because the magnetic flux provided by permanent magnet materials is relatively stable and cannot be adjusted, the field weakening speed extension capability of permanent magnet synchronous motors is poor. Summary of the Invention

[0003] The main objective of this invention is to provide a centrifugal variable flux permanent magnet motor and a method for increasing or decreasing the leakage flux of the permanent magnet in the motor. This method allows the magnetic guide block of the motor rotor to change its position at different speeds under the influence of centrifugal force and spring tension, thereby reducing or increasing the leakage flux resistance of the permanent magnet circuit, thus reducing or increasing the permanent magnet magnetic field in the air gap, and further improving the motor torque density and the ability to increase speed by weakening the field.

[0004] The objective of this invention can be achieved by adopting the following technical solution:

[0005] A centrifugal variable flux permanent magnet motor includes a stator mechanism and a rotor mechanism. The rotor mechanism includes a magnetically conductive block, a spring, a non-magnetically conductive block, a permanent magnet, a non-magnetically conductive body, and a rotor core.

[0006] The rotor core is provided with a number of permanent magnet pairs. Each permanent magnet pair includes six permanent magnet segments. The six permanent magnet segments are respectively arranged in adjacent "U"-shaped and "I"-shaped sections. Both ends of the U-shaped section of each of the six permanent magnet segments are provided with grooves, and magnetic conductive blocks are slidably arranged in the grooves.

[0007] Non-magnetic blocks are placed circumferentially between two adjacent pairs of permanent magnets and at both ends of the U-shaped section of the six permanent magnets near the rotor core surface. The non-magnetic blocks and the rotor core form a smooth surface in the radial direction.

[0008] Non-magnetic materials are fixed to the radial surfaces of the U-shaped sections of the six permanent magnets near the rotor core surface at both ends, and the magnetic blocks are connected by springs and non-magnetic materials.

[0009] Preferably, it also includes a stator mechanism, which includes a stator core and a stator winding. The stator core has a plurality of stator slots along the circumferential direction, and a stator tooth is formed between two adjacent stator slots. The outer ends of two adjacent stator teeth are connected to form a stator yoke. The stator winding is placed in the stator slots.

[0010] Preferably, the stator winding is configured as a distributed winding.

[0011] Preferably, the non-magnetic body is fixed to the radial outer side of the permanent magnets at both ends of the U-shaped portion of the six permanent magnets.

[0012] Preferably, the length of the groove along the circumferential direction is less than the length of the permanent magnets at both ends of the U-shaped portion along the circumferential direction.

[0013] Preferably, the magnetic field of the motor forms a closed loop through the stator mechanism and the rotor mechanism.

[0014] A method to increase the leakage flux of permanent magnets in an electric motor.

[0015] The method includes running the rotor mechanism at a speed above the rated speed and within a preset range. The magnetic block is affected by centrifugal force, overcomes the spring tension, and gradually approaches the surface of the rotor core until it is flush with the surface of the rotor core, thereby increasing the leakage magnetism of the permanent magnet.

[0016] A method to reduce magnetic leakage in permanent magnets of an electric motor.

[0017] The method includes running the rotor mechanism at a speed below the rated speed and within a preset range, with the magnetic block being pulled by a spring and gradually moving away from the position of the rotor core surface until it is flush with the center line of the non-magnetic block along the circumferential direction, thereby reducing the leakage magnetism of the permanent magnet.

[0018] Beneficial technical effects of the present invention:

[0019] The magnetic guide block of the motor rotor provided by this invention is affected by centrifugal force and spring tension, and can change the position of the magnetic guide block at different speeds to reduce or increase the leakage magnetic resistance of the permanent magnet flux, thereby reducing or increasing the permanent magnet magnetic field in the air gap, thus improving the motor torque density and the field weakening speed extension capability. Moreover, the overall structure of the motor is not complicated, and it is very convenient to install and use. The method of increasing and reducing the leakage magnetic flux of the permanent magnet of the motor provided by this invention is simple to operate and easy to implement, and will not make the overall structure of the motor more complicated, resulting in lower production and maintenance costs. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the radial cross-sectional structure of the centrifugal variable flux permanent magnet motor provided by the present invention when it operates at a higher speed above the rated speed.

[0021] Figure 2 This is a schematic diagram of the radial rotor cross-section structure of the 1 / 12 centrifugal variable flux permanent magnet motor provided by the present invention when operating at a higher speed above the rated speed.

[0022] Figure 3This is a schematic diagram of the radial cross-sectional structure of the centrifugal variable flux permanent magnet motor provided by the present invention when it operates at a lower speed below the rated speed.

[0023] Figure 4 This is a schematic diagram of the radial rotor cross-section structure of the 1 / 12 centrifugal variable flux permanent magnet motor provided by the present invention when operating at a lower speed below the rated speed.

[0024] Figure 5 The magnetic vector diagram of the 1 / 6 centrifugal variable flux permanent magnet motor provided by the present invention when it is running at a higher speed above the rated speed.

[0025] Figure 6 The magnetic vector diagram of the 1 / 6 centrifugal variable flux permanent magnet motor provided by the present invention when operating at a lower speed below the rated speed.

[0026] In the diagram: 1-Stator core, 2-Stator winding, 3-Magnetic block, 4-Spring, 5-Non-magnetic block, 6-Permanent magnet, 7-Non-magnetic body, 8-Rotor core. Detailed Implementation

[0027] To enable those skilled in the art to understand the technical solution of the present invention more clearly, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0028] like Figures 1-6 As shown, this embodiment provides a centrifugal variable flux permanent magnet motor, which includes a stator mechanism and a rotor mechanism;

[0029] The stator mechanism includes a stator core 1 and a stator winding 2. The stator core 1 has several stator slots evenly distributed along the circumferential direction. Stator teeth are formed between adjacent stator slots. The outer ends of two adjacent stator teeth are connected to form a stator yoke. The stator winding 2 is placed in the stator slots and adopts the form of distributed winding.

[0030] The rotor mechanism includes a rotor core 8, a permanent magnet 6, a magnetic block 3, a non-magnetic block 5, a non-magnetic body 7, and a spring 4;

[0031] Several pairs of built-in permanent magnets are arranged inside the rotor core 8. Each pair of permanent magnets includes six built-in permanent magnet segments 6, arranged in a U+I shape, that is, the six permanent magnet segments are arranged in adjacent "U"-shaped and "I"-shaped sections, such as... Figure 2 As shown, this forms a magnetic pole;

[0032] In the U-shaped permanent magnet pair, the permanent magnet 6 near the surface of the rotor core 8 has slots at both ends that are radially parallel to the permanent magnet 6. That is, one end of the permanent magnet 6 at the left and right ends of the U-shaped permanent magnet pair has a slot that is radially parallel to the corresponding permanent magnet 6. A magnetic conductive block 3 is slidably disposed in the slot. The length of the slot along the circumferential direction is slightly smaller than the length of the permanent magnet 6 at both ends of the U-shaped permanent magnet pair along the circumferential direction.

[0033] Between two adjacent U+1 type permanent magnet pairs along the circumferential direction, non-magnetic blocks 5 are placed at both ends of the permanent magnet 6 near the surface of the rotor core 8 in the U-type permanent magnet pair along the circumferential direction, and the non-magnetic blocks 5 and the rotor core 8 form a smooth surface along the radial direction.

[0034] Non-magnetic materials 7 are fixed on the radial surfaces of the permanent magnets 6 at both ends of the U-shaped permanent magnet pair near the surface of the rotor core 8. These two ends are the permanent magnets 6 located at the left and right ends of the U-shaped permanent magnet pair. That is, non-magnetic materials 7 are fixed on the radial surfaces of one end of each of the two permanent magnets 6. The magnetic block 3 is connected to the non-magnetic material 7 by the spring 4. The magnetic block 3 can slide radially in the smooth groove.

[0035] The magnetic field inside the motor forms a closed loop through the stator and rotor mechanisms.

[0036] In this embodiment, the magnetic block moves its position according to the rotational speed of the rotor mechanism, thereby adjusting its distance from the rotor core surface.

[0037] In this embodiment, the non-magnetic body 7 is fixed on the radial outer side of the permanent magnet 6 near the surface of the rotor core 8 of the U-shaped permanent magnet pair.

[0038] A method for reducing magnetic leakage of permanent magnets in an electric motor includes having the magnetically conductive block 3, primarily pulled by the spring 4, located at a position farthest from the surface of the rotor core 8 when the rotor mechanism operates at a lower speed below the rated speed. The block is flush with the center line of the non-magnetically conductive block 7 along the circumferential direction, thus reducing magnetic leakage of the permanent magnet. (See also...) Figure 2 , Figure 5 .

[0039] A method for increasing the leakage flux of a permanent magnet in a motor includes having the magnetically conductive block 3, primarily subjected to centrifugal force to overcome the tension of the spring 4, positioned close to, and eventually flush with, the surface of the rotor core 8 when the rotor mechanism is running at a higher speed above its rated speed. This increases the leakage flux of the permanent magnet and expands the speed range. See [link to relevant documentation]. Figure 4 , Figure 6 .

[0040] In summary, in this embodiment, the magnetic guide block 3 of the motor rotor provided in this embodiment is affected by centrifugal force and spring 4 tension respectively, and can change the position of the magnetic guide block 3 at different speeds, reduce or increase the leakage magnetic resistance of the permanent magnet flux, thereby reducing or increasing the permanent magnet magnetic field in the air gap, thereby improving the motor torque density and the field weakening speed expansion capability. Moreover, the overall structure of the motor is not complicated, and it is very convenient to install and use.

[0041] The above description is merely a further embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope disclosed in the present invention, based on the technical solution and concept of the present invention, shall fall within the scope of protection of the present invention.

Claims

1. A centrifugal variable flux permanent magnet motor, comprising a stator mechanism and a rotor mechanism, characterized in that: The rotor mechanism includes a magnetic block (3), a spring (4), a non-magnetic block (5), a permanent magnet (6), a non-magnetic body (7), and a rotor core (8). The rotor core (8) is provided with a number of permanent magnet pairs. Each permanent magnet pair includes six permanent magnet segments (6). The six permanent magnet segments (6) are arranged in adjacent "U"-shaped and "I"-shaped sections. Both ends of the U-shaped section of the six permanent magnet segments (6) are provided with grooves. Magnetic blocks (3) are slidably arranged in the grooves. Non-magnetic blocks (5) are placed in the circumferential direction between two adjacent pairs of permanent magnets and at both ends of the U-shaped part of the six permanent magnets (6) near the surface of the rotor core (8). The non-magnetic blocks (5) and the rotor core (8) form a smooth surface in the radial direction. Non-magnetic materials (7) are fixed to the radial surfaces of the U-shaped part of the six permanent magnets (6) near the rotor core (8), and the magnetic blocks (3) are connected to the non-magnetic materials (7) by springs (4); It also includes a stator mechanism, which includes a stator core (1) and a stator winding (2). The stator core (1) has several stator slots along the circumferential direction, and stator teeth are formed between two adjacent stator slots. The outer ends of two adjacent stator teeth are connected to form a stator yoke. The stator winding (2) is placed in the stator slots. The magnetic field of the motor forms a closed loop through the stator and rotor mechanisms.

2. The centrifugal variable flux permanent magnet motor according to claim 1, characterized in that: The stator winding (2) is set up in the form of a distributed winding.

3. The centrifugal variable flux permanent magnet motor according to claim 1, characterized in that: The non-magnetic body (7) is fixed to the radial outer side of the permanent magnets at both ends of the U-shaped part of the six permanent magnets (6).

4. The centrifugal variable flux permanent magnet motor according to claim 1, characterized in that: The length of the groove along the circumferential direction is less than the length of the permanent magnets (6) at both ends of the U-shaped part along the circumferential direction.

5. A method for increasing the leakage flux of a permanent magnet in a motor, characterized in that: The motor is a centrifugal variable flux permanent magnet motor as described in any one of claims 1 to 4; The method includes running the rotor mechanism at a speed above the rated speed and within a preset range. The magnetic block (3) is affected by centrifugal force, overcomes the tension of the spring (4), and gradually approaches the surface of the rotor core (8) until it is flush with the surface of the rotor core (8), thereby increasing the leakage magnetism of the permanent magnet.

6. A method for reducing leakage flux in permanent magnets of an electric motor, characterized in that: The motor is a centrifugal variable flux permanent magnet motor as described in any one of claims 1 to 4; The method includes running the rotor mechanism at a speed below the rated speed and within a preset range, with the magnetic block (3) being pulled by the spring (4) and gradually moving away from the position of the rotor core (8) until it is flush with the center line of the non-magnetic block (7) along the circumferential direction, thereby reducing the leakage magnetism of the permanent magnet.

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