A built-in motor rotor structure saving permanent magnet consumption

Abstract

The utility model provides a kind of built-in motor rotor structure of saving permanent magnet amount, belong to motor technical field.Solve the cost of existing permanent magnet motor mainly using neodymium iron boron material is too high.It includes multiple magnetic poles distributed on rotor core along circumference, each the magnetic pole is composed of first permanent magnet and second permanent magnet, the first permanent magnet is located in the middle of magnetic pole, the first permanent magnet is neodymium iron boron material, the second permanent magnet is located on the radial outer side of first permanent magnet and covers both ends, the second permanent magnet is ferrite material, the second permanent magnet is used to suppress leakage flux and magnetically separate first permanent magnet.It is mainly used for permanent magnet synchronous motor.

Description

Technical Field

[0001] This utility model belongs to the field of electric motor technology, and in particular relates to an internal motor rotor structure that saves on the amount of permanent magnets used. Background Technology

[0002] Permanent magnet synchronous motors (PMSMs) are excited by permanent magnets, eliminating rotor losses and effectively improving motor efficiency. PMSMs exhibit a significant efficiency advantage under light load conditions, maintaining high efficiency within the 20%-100% range, while asynchronous motor efficiency drops sharply with decreasing output power. The power factor of PMSMs is also significantly improved compared to asynchronous motors, typically reaching above 0.95. However, the primary permanent magnet material currently used in PMSMs is neodymium iron boron (NdFeB), which is expensive, resulting in a significantly higher cost compared to asynchronous motors. Furthermore, the built-in rotor structure, due to the presence of a magnetic isolation bridge, causes a portion of the magnetic flux generated by the NdFeB magnets to form a localized self-circulation, failing to effectively participate in the main magnetic circuit of the stator-rotor air gap, thus reducing the utilization rate of the permanent magnets. Utility Model Content

[0003] In view of this, the present invention aims to propose an internal motor rotor structure that saves the amount of permanent magnets used, in order to solve the problem that the existing permanent magnet motors mainly use neodymium iron boron materials, resulting in excessively high costs.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: a built-in motor rotor structure that saves on the amount of permanent magnets, comprising multiple magnetic poles distributed circumferentially on the rotor core, each magnetic pole being composed of a first permanent magnet and a second permanent magnet, the first permanent magnet being located in the middle of the magnetic pole and being made of neodymium iron boron, the second permanent magnet being located radially outside the first permanent magnet and covering both ends thereof, the second permanent magnet being made of ferrite, the second permanent magnet being used to suppress leakage flux and to provide magnetic isolation for the first permanent magnet.

[0005] Furthermore, the magnetic poles are V-shaped structures, which are composed of two symmetrically arranged first permanent magnets, with two second permanent magnets respectively located at both ends of the V-shaped structure.

[0006] Furthermore, the remanence density of the first permanent magnet is higher than that of the second permanent magnet, and the leakage flux of the second permanent magnet is less than that of the first permanent magnet.

[0007] Furthermore, the second permanent magnet is arranged adjacent to the magnetic isolation bridge of the rotor core.

[0008] Furthermore, the mass ratio of the first permanent magnet to the second permanent magnet is between 10:1 and 12:1.

[0009] Furthermore, the magnetic poles are disposed in the magnetic slots on the rotor core.

[0010] Furthermore, the rotor core is formed by stacking multiple rotor laminations.

[0011] Compared with the prior art, the beneficial effects of this utility model are: 1. This utility model provides a built-in motor rotor structure that saves on the amount of permanent magnets. By combining a first permanent magnet made of neodymium iron boron and a second permanent magnet made of ferrite, the amount of high-cost neodymium iron boron is reduced, while only low-cost ferrite is added, thus appropriately reducing the cost of permanent magnet materials. 2. This utility model provides a built-in motor rotor structure that saves on the amount of permanent magnets. The second permanent magnet is placed in the region adjacent to the magnetic isolation bridge of the rotor core at the magnetic extreme end. By utilizing the characteristics of low remanence and low permeability of ferrite, the leakage of magnetic flux from the first permanent magnet through the magnetic isolation bridge is blocked, allowing more magnetic flux to enter the stator winding to form effective working magnetic flux, reducing the waste caused by magnetic circuit self-circulation, effectively suppressing leakage magnetic flux, and improving magnetic utilization. Attached Figure Description

[0012] The accompanying drawings, which form part of this utility model, are used to provide a further understanding of the utility model. The illustrative embodiments of the utility model and their descriptions are used to explain the utility model and do not constitute an undue limitation of the utility model. In the drawings: Figure 1 This is a schematic diagram of a built-in motor rotor structure that saves on the amount of permanent magnets described in this utility model; Figure 2 Diagram showing a single-magnet rotor structure with an internal motor; Figure 3 Diagram showing the structure of a combined magnet rotor with an internal motor; Figure 4 A simulation diagram of leakage flux for a single-magnet rotor structure with an internal motor; Figure 5 This is a simulation diagram of the leakage flux of the built-in motor rotor structure that saves permanent magnets, as described in this utility model.

[0013] 1-First permanent magnet, 2-Second permanent magnet, 3-Magnetic bridge. Detailed Implementation

[0014] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present utility model can be combined with each other, and the described embodiments are only some embodiments of the present utility model, not all embodiments.

[0015] See Figure 1-5This embodiment describes a built-in motor rotor structure that saves on permanent magnet usage. It includes multiple magnetic poles distributed circumferentially on a rotor core. The magnetic poles are disposed within magnetic slots on the rotor core. Each magnetic pole is composed of a first permanent magnet 1 and a second permanent magnet 2. The first permanent magnet 1 is located in the center of the pole and is made of neodymium iron boron (NdFeB). The second permanent magnet 2 is located radially outside the first permanent magnet 1 and covers both ends of it. The second permanent magnet 2 is made of ferrite. The second permanent magnet 2 suppresses leakage flux and acts as a magnetic shield for the first permanent magnet 1. The second permanent magnet 2 provides a portion of the main magnetic flux and suppresses leakage flux from the first permanent magnet. By combining the first permanent magnet 1 (NdFeB) with the second permanent magnet 2 (ferrite), the amount of high-cost NdFeB is reduced, while only low-cost ferrite is added, appropriately lowering the cost of permanent magnet materials.

[0016] In this embodiment, the magnetic pole is a V-shaped structure, which is composed of two symmetrically arranged first permanent magnets 1, and two second permanent magnets 2 are respectively disposed at both ends of the V-shaped structure.

[0017] In this embodiment, the remanence density of the first permanent magnet 1 is higher than that of the second permanent magnet 2, and the leakage flux of the second permanent magnet 2 is less than that of the first permanent magnet 1. This is because there is a magnetic isolation bridge 3 at the magnetic end. Furthermore, neodymium iron boron permanent magnets have better magnetic properties and a larger leakage flux. Conversely, ferrite permanent magnets have a lower remanence density and a smaller leakage flux. Additionally, ferrite itself does not have magnetic permeability, which also acts as a magnetic isolation barrier for the neodymium iron boron material in the middle section. Simulation diagrams of leakage flux for the single-magnet rotor structure of the built-in motor and the built-in motor rotor structure that saves on permanent magnet usage are shown below. Figure 4 and Figure 5 As shown.

[0018] In this embodiment, the second permanent magnet 2 is arranged adjacent to the magnetic isolation bridge 3 of the rotor core. The second permanent magnet 2 is placed in the region adjacent to the magnetic end of the magnetic pole and the magnetic isolation bridge 3 of the rotor core. By utilizing the characteristics of low remanence and low permeability of ferrite, the magnetic flux of the first permanent magnet 1 is blocked from leaking through the magnetic isolation bridge 3, so that more magnetic flux enters the stator winding to form effective working magnetic flux, reducing the waste caused by magnetic circuit self-circulation, effectively suppressing leakage magnetic flux, and improving magnetic utilization.

[0019] In this embodiment, the mass ratio of the first permanent magnet 1 to the second permanent magnet 2 is between 10:1 and 12:1.

[0020] In this embodiment, the rotor core is formed by stacking multiple rotor laminations.

[0021] This embodiment uses a 1120kW 6-pole V-type internal permanent magnet motor as an example for motor analysis model. The rated parameters of this motor are shown in Table 1: Table 1: Rated Parameters of Motors

[0022] Through theoretical analysis and simulation calculations, an attempt was made to use a permanent magnet structure with composite materials to ensure electromagnetic performance such as back electromotive force, power factor, efficiency, and maximum torque, while maintaining the same parameters for the motor stator laminations, stator windings, and core length. The cost of the permanent magnet was attempted to be reduced by adjusting its dimensions. Two structures were developed: a single-magnet rotor structure and a combined magnet rotor structure with an integrated motor, as shown below. Figure 2 and Figure 3 As shown.

[0023] Although the rotor structure adopts two types of magnets, the key performance parameters of the motor must remain basically the same. The five key parameters of the variable frequency speed control permanent magnet motor under the two rotor structures are shown in Table 2: Table 2: Key parameters of motors with two rotor structures

[0024] Ultimately, by calculating the weight of the permanent magnets in the motors with the two rotor structures, it was found that the single NdFeB permanent magnet structure uses 64.12 kg of NdFeB material, while the combined magnet structure uses 60.36 kg of NdFeB and 5.99 kg of ferrite, resulting in a 5.86% saving in NdFeB material usage.

[0025] The embodiments of the present invention disclosed above are merely illustrative of the present invention. The embodiments do not exhaustively describe all details, nor do they limit the present invention to the specific implementations described. Many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention.

Claims

1. A built-in motor rotor structure that saves on the amount of permanent magnets, characterized in that: It includes multiple magnetic poles distributed circumferentially on the rotor core. Each magnetic pole is composed of a first permanent magnet (1) and a second permanent magnet (2). The first permanent magnet (1) is located in the middle of the magnetic pole and is made of neodymium iron boron. The second permanent magnet (2) is located on the radial outside of the first permanent magnet (1) and covers both ends of it. The second permanent magnet (2) is made of ferrite and is used to suppress leakage flux and to isolate the first permanent magnet (1).

2. The built-in motor rotor structure for saving permanent magnet usage according to claim 1, characterized in that: The magnetic pole is a V-shaped structure, which is composed of two symmetrically arranged first permanent magnets (1) and two second permanent magnets (2) respectively located at both ends of the V-shaped structure.

3. The built-in motor rotor structure for saving permanent magnet usage according to claim 1, characterized in that: The remanence density of the first permanent magnet (1) is higher than that of the second permanent magnet (2), and the leakage flux of the second permanent magnet (2) is less than that of the first permanent magnet (1).

4. The built-in motor rotor structure for saving permanent magnet usage according to claim 1, characterized in that: The second permanent magnet (2) is arranged adjacent to the magnetic isolation bridge (3) of the rotor core.

5. The built-in motor rotor structure for saving permanent magnet usage according to claim 1, characterized in that: The mass ratio of the first permanent magnet (1) to the second permanent magnet (2) is between 10:1 and 12:

1.

6. The built-in motor rotor structure for saving permanent magnet usage according to claim 1, characterized in that: The magnetic poles are arranged in the magnetic slots on the rotor core.

7. The built-in motor rotor structure for saving permanent magnet usage according to claim 1, characterized in that: The rotor core is formed by stacking multiple rotor laminations.

Images