CN115276285A - A high torque density motor rotor structure with efficient use of permanent magnets - Google Patents

Abstract

The invention discloses a high torque density motor rotor structure with efficient use of permanent magnets. and a plurality of the main permanent magnets are assembled in the rotor iron core along the circumferential direction of the rotor iron core, and each piece of the main permanent magnets is located at the end of the rotor iron core along the axial direction of the rotor iron core. Two pieces of the auxiliary permanent magnets are respectively arranged on both sides, and the two pieces of the auxiliary permanent magnets are covered and connected by the magnetic conductive bridge. The number of the auxiliary permanent magnets is four times that of the main permanent magnets. The auxiliary permanent magnets are magnetized along the radial direction of the rotor core, and the auxiliary permanent magnets are magnetized along the axial direction of the rotor core. The beneficial effects of the present invention are: compared with the traditional built-in permanent magnet synchronous motor, the average output torque is increased by more than 8% under the condition that the total amount of permanent magnets is the same and the total volume of the motor is roughly unchanged, and the high efficiency of the permanent magnets is realized. Take advantage of the high torque density of the motor.

Description

A high torque density motor rotor structure with efficient utilization of permanent magnets

technical field

The invention relates to the technical field of motors, in particular to a rotor structure of a high torque density motor with efficient utilization of permanent magnets.

Background technique

In the fields of automobiles, rail transit, aerospace and household appliances, permanent magnet synchronous motors have been widely used. The magnetic field is generated by permanent magnets, which avoids the existence of structures such as brushes and slip rings, and its performance varies with the permanent magnet material. The development and continuous improvement, especially the application of rare earth permanent magnet materials, so it has many advantages such as high power density, high efficiency and high power factor. China is rich in rare earth resources, but they are non-renewable resources, and there are problems such as high cost and limited supply. Therefore, it is of great theoretical significance and practical value to give full play to the advantages of China's rich rare earth resources and the protection and efficient utilization of rare earth resources. For permanent magnet motors, increasing the output power or torque generated by the unit amount of permanent magnets is one of the important factors to measure its design level and electromagnetic performance.

In order to meet the requirement of high output torque of the motor, the existing technology increases the amount of permanent magnets and the volume of the motor on the one hand, but it increases the cost of the motor, reduces the torque density of the motor and may cause waste of permanent magnet materials; On the one hand, it increases the winding current, but it increases the copper loss and puts forward higher requirements on the cooling form of the motor. In order to meet the requirement of less rare earths or no rare earths in the motor, the existing technology uses materials such as ferrite or reluctance motors, etc., but it reduces the performance of the motor, such as a decrease in power density and an increase in torque fluctuation. It is practical in engineering Not much value.

Contents of the invention

The invention discloses a high-torque-density motor rotor structure with high-efficiency utilization of permanent magnets, which can effectively solve the technical problems involved in the background technology.

To achieve the above object, the technical solution of the present invention is:

A high torque density motor rotor structure with efficient utilization of permanent magnets, including a rotor, the rotor includes a rotor core, a magnetic bridge, a main permanent magnet and a secondary permanent magnet, the number of the main permanent magnets is multiple, and the number of the main permanent magnets is multiple One piece of the main permanent magnet is assembled in the rotor core along the circumferential direction of the rotor core, and each of the main permanent magnets is respectively arranged on both sides of the end part along the axial direction of the rotor core Two pieces of the auxiliary permanent magnets, the two auxiliary permanent magnets are covered and connected by the magnetic bridge, the main permanent magnets are magnetized along the radial direction of the rotor iron core, and the auxiliary permanent magnets are magnetized along the rotor iron core Axial magnetization of the core.

As a preferred improvement of the present invention, the main permanent magnet and the auxiliary permanent magnet are made of the same permanent magnet material.

As a preferred improvement of the present invention, the number of the auxiliary permanent magnets is four times that of the main permanent magnets.

As a preferred improvement of the present invention, the magnetic permeable bridge is square.

As a preferred improvement of the present invention, the main permanent magnet is embedded in the rotor core, and the parts on both sides of the main permanent magnet near the upper and lower ends are cut off to form the auxiliary permanent magnet. total usage.

As a preferred improvement of the present invention, the primary and secondary permanent magnets are arranged at the peripheral axial ends of the rotor core, and the secondary permanent magnets are covered and connected by the magnetic bridge.

As a preferred improvement of the present invention, after the parts on both sides of the end of the main permanent magnet close to the upper and lower ends are cut, the hollow slots on the rotor core for embedding the main permanent magnet are close to the two sides of the end The part is filled with the same material as the rotor core.

As a preferred improvement of the present invention, the main permanent magnets are evenly distributed along the circumferential direction of the rotor core, and the auxiliary permanent magnets are arranged on the end face of the rotor core and opposite to the rotor core on both sides in the axial direction. The main permanent magnet presents a clamping shape.

The beneficial effects of the present invention are as follows:

1) The auxiliary permanent magnet and the magnetic bridge are assembled at the ends of both sides of the rotor, which just fill the cavity between the end of the motor rotor and the bearing, so the total volume of the motor remains roughly the same, while the output torque increases, realizing High torque density;

2) The auxiliary permanent magnet is assembled on both sides of the rotor and adjacent to the main permanent magnet. It is connected by a magnetic bridge to form a magnetic circuit. Given the same armature winding current, the motor is compared with the traditional built-in permanent magnet synchronous motor. Under the same total amount of permanent magnets, the average output torque is increased by more than 8%, realizing the efficient utilization of permanent magnets.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings that need to be used in the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without creative work, wherein:

Fig. 1 is the three-dimensional structure schematic diagram of the high torque density motor rotor structure of permanent magnet efficient utilization of the present invention;

Fig. 2 is the exploded structure schematic diagram of the high torque density motor rotor structure of permanent magnet efficient utilization of the present invention;

Fig. 3 is the magnetic circuit diagram of the high torque density motor rotor structure of the permanent magnet efficient utilization of the present invention;

Figure 4 is a three-dimensional diagram of the motor air gap flux density of a traditional built-in permanent magnet synchronous motor;

Fig. 5 is the three-dimensional diagram of the motor air-gap magnetic density of the permanent magnet synchronous motor that the permanent magnet of the present invention utilizes efficiently;

Fig. 6 is a graph showing the motor output torque curves of the permanent magnet synchronous motor with efficient utilization of permanent magnets of the present invention and the traditional built-in "one" type permanent magnet synchronous motor.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention. Apparently, the described embodiments are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiments of the present invention are only used to explain the relationship between the components in a certain posture (as shown in the figure). Relative positional relationship, movement conditions, etc., if the specific posture changes, the directional indication will also change accordingly.

In addition, in the present invention, descriptions such as "first", "second" and so on are used for description purposes only, and should not be understood as indicating or implying their relative importance or implicitly indicating the quantity of indicated technical features. Thus, the features defined as "first" and "second" may explicitly or implicitly include at least one of these features. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

In the present invention, unless otherwise specified and limited, the terms "connection" and "fixation" should be understood in a broad sense, for example, "fixation" can be a fixed connection, a detachable connection, or an integral body; It can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediary, and it can be an internal communication between two elements or an interaction relationship between two elements, unless otherwise clearly defined. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present invention according to specific situations.

In addition, the technical solutions of the various embodiments of the present invention can be combined with each other, but it must be based on the realization of those skilled in the art. When the combination of technical solutions is contradictory or cannot be realized, it should be considered as a combination of technical solutions. Does not exist, nor is it within the scope of protection required by the present invention.

Please refer to Figs. 1 and 2, the present invention provides a high-torque-density motor rotor structure for efficient utilization of permanent magnets, including a rotor, which includes a rotor core 2, a magnetic bridge 3, a main permanent magnet 5 and an auxiliary permanent magnet6. The number of the main permanent magnets 5 is multiple, the number of the auxiliary permanent magnets 6 is four times that of the main permanent magnets 5, and the main permanent magnets 5 and the auxiliary permanent magnets 6 are made of the same permanent magnet material.

A plurality of the main permanent magnets 5 are evenly assembled in the rotor core 2 along the circumferential direction of the rotor core 2, and the parts on both sides of the main permanent magnet 5 near the ends are cut off to form the The total consumption of the auxiliary permanent magnets 6, the hollow slots on the rotor core 2 for embedding the main permanent magnets 5 are filled with the same material as that of the rotor core 2 near both sides of the end.

Each of the main permanent magnets 5 is provided with two auxiliary permanent magnets 6 on both sides of the upper and lower ends of the axial direction of the rotor core 2, and the two auxiliary permanent magnets 6 pass through the guides. The magnetic bridge 3 covers and connects, and the auxiliary permanent magnet 6 clamps the ends of the main permanent magnet 5 on both sides in the axial direction. Specifically, the magnetic bridge 3 is in a square shape.

It should be noted that the rotor is surrounded by a stator, and the stator includes a stator core 4 and an armature winding 1 assembled on the stator core 4 . Specifically, the stator core 4 is in the shape of a hollow cylinder, and a set of armature windings is assembled on the inner periphery of the stator core 4 .

Further, as shown in FIG. 3 , the main permanent magnet 5, the rotor core 2 and the stator core 4 constitute the main permanent magnet magnetic circuit 7, and the auxiliary permanent magnet 6, the magnetic bridge 3, and the rotor core 2 and the stator core 4 constitute a secondary permanent magnet magnetic circuit 8, in addition, the main permanent magnet 5 is magnetized along the radial direction of the rotor core 2, and the secondary permanent magnet 6 is magnetized along the axial direction of the rotor core 2 , In this way, the magnetic flux generated by the main permanent magnet 5 and the magnetic flux generated by the auxiliary permanent magnet 6 are in the same radial direction, and they together constitute the main magnetic flux of the motor.

Compared with the square permanent magnet of the traditional built-in motor, the length of the magnetization direction of the main permanent magnet 5 is reduced (the overall reduction or the part near the ends on both sides of the rotor core 2 is reduced), and the anti-demagnetization ability of the main permanent magnet is slightly reduced , but the auxiliary permanent magnets 6 on both sides of the rotor end provide additional magnetic flux, so that the total magnetic flux provided by the main permanent magnet 5 and auxiliary permanent magnet 6 of the motor to the external magnetic circuit becomes larger, so that under the same conditions The motor has a larger output torque.

In addition, the traditional built-in permanent magnet synchronous motor and the permanent magnet synchronous motor model with efficient use of permanent magnets are established in the finite element 3D software. First, the air gap flux density of the motor under no-load conditions is calculated through the static field, as shown in Figures 4 and 5. Show. It can be seen from Figures 4 and 5 that the permanent magnet synchronous motor with efficient utilization of permanent magnets has the existence of auxiliary permanent magnets 6 at the ends of both sides of the rotor, and the average magnetic density on both sides of the ends in the axial direction increases, making The average density of the total air gap of the motor is increased, which realizes the efficient utilization of permanent magnets.

Under the condition of the rated load of the motor, given the same current, the output torque curves of the traditional built-in permanent magnet synchronous motor and the permanent magnet synchronous motor with efficient use of permanent magnets are shown in Figure 6, and the average torque values are 10.84Nm and 11.72Nm. Compared with the former, the average torque value of the latter is increased by more than 8% under the premise of the same given current and the same amount of permanent magnets. The reason is that the reduction of each main permanent magnet 5 is equal to the total consumption of four auxiliary permanent magnets 6 on both sides of its end, so the total volume of all main permanent magnets 5 and auxiliary permanent magnets 6 remains constant. It is equal to the total amount of permanent magnets used in the rotor of a traditional built-in motor. Therefore, under the condition that the permanent magnet synchronous motor with efficient utilization of permanent magnets and the conventional motor have a certain total amount of permanent magnets and given the same armature winding current, the former can output more than 8% of the average torque compared with the latter.

The beneficial effects of the present invention are as follows:

1) The auxiliary permanent magnet and the magnetic bridge are assembled at the ends of both sides of the rotor, which just fill the cavity between the end of the rotor and the bearing, so the total volume of the motor remains roughly the same, while the output torque increases, achieving high torque density;

2) The auxiliary permanent magnet is assembled on both sides of the rotor and adjacent to the main permanent magnet. It is connected by a magnetic bridge to form a magnetic circuit. Given the same armature winding current, the motor is compared with the traditional built-in permanent magnet synchronous motor. Under the same total amount of permanent magnets, the average value of output torque is increased by 8%, which realizes the efficient utilization of permanent magnets.

Although the embodiment of the present invention has been disclosed as above, it is not limited to the use listed in the specification and embodiment, it can be applied to various fields suitable for the present invention, and it can be easily understood by those skilled in the art Further modifications can be effected, so the invention is not limited to the specific details and examples shown and described herein without departing from the general concept defined by the claims and their equivalents.

Claims (8)

1. A high torque density motor rotor structure with efficient utilization of permanent magnets, characterized in that it comprises a rotor, the rotor includes a rotor core, a magnetic bridge, a main permanent magnet and a secondary permanent magnet, and the number of the main permanent magnets There are multiple pieces, and multiple main permanent magnets are assembled in the rotor core along the circumferential direction of the rotor core, and the end of each main permanent magnet along the axial direction of the rotor core Two pieces of the auxiliary permanent magnets are respectively arranged on both sides of the part, and the two auxiliary permanent magnets are covered and connected by the magnetic bridge, the main permanent magnets are magnetized along the radial direction of the rotor core, and the auxiliary permanent magnets are The magnets are magnetized along the axial direction of the rotor core. 2 . The rotor structure of a high torque density motor with efficient utilization of permanent magnets according to claim 1 , wherein the main permanent magnet and the auxiliary permanent magnet are made of the same permanent magnet material. 3 . The rotor structure of a high torque density motor with efficient utilization of permanent magnets according to claim 2 , wherein the number of the auxiliary permanent magnets is four times that of the main permanent magnets. 4 . 4 . The rotor structure of a high-torque-density motor with efficient utilization of permanent magnets according to claim 2 , wherein the magnetic bridge is square. 5. The rotor structure of a high-torque-density motor with efficient utilization of permanent magnets according to claim 1 or 4, characterized in that: the main permanent magnet is embedded in the rotor core, and the main permanent magnet The amount cut off on both sides of the ends near the upper and lower ends constitutes the total amount of the auxiliary permanent magnet. 6. The rotor structure of a high torque density motor with efficient utilization of permanent magnets according to claim 5, characterized in that: the auxiliary permanent magnet is arranged at the axial end of the rotor core, and the auxiliary permanent magnet The magnet is covered and connected by the magnetic permeable bridge. 7. The rotor structure of a high torque density motor with efficient utilization of permanent magnets according to claim 5, characterized in that: after the parts on both sides of the ends of the main permanent magnet close to the upper and lower ends are cut, the rotor iron The parts near the two sides of the end of the hollow slot for embedding the main permanent magnet on the core are filled with the same material as that of the rotor core. 8. The rotor structure of a high-torque-density motor with high-efficiency utilization of permanent magnets according to claim 1 or 7, characterized in that: the main permanent magnets are evenly distributed along the circumferential direction of the rotor core, and the The auxiliary permanent magnet is arranged on the end face of the rotor iron core and presents a clamping shape to the ends of the main permanent magnet on both sides in the axial direction.

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