CN204578332U - A kind of motor of application of synchronized magnetoresistive structures - Google Patents

Abstract

The utility model discloses a motor using a synchronous reluctance structure, which includes a stator and a rotor, the stator includes a stator core and a winding, the rotor includes a rotor core, and is characterized in that: the rotor core is laminated by rotor punching sheets The rotor punching sheet includes several symmetrical magnetic poles, the magnetic poles are arranged alternately along the circumference of the rotor with N poles and S poles, the magnetic poles include multi-layer grids, and the adjacent grids in each grid layer The relationship between the spacing W between the grids and the air gap δ between the stator and the rotor is: δ/3≤W≤3δ, part of the grid is placed with magnetic steel, and other parts are left blank or placed in non-conductive materials such as epoxy resin. Magnetic and non-conductive materials, the structure saves cost and has simple processing technology, and the motor has a wide speed regulation range, a large salient pole ratio and small torque fluctuations.

Description

A motor using synchronous reluctance structure

technical field

The utility model relates to a synchronous reluctance motor structure, in particular to a permanent magnet assisted synchronous reluctance motor rotor structure.

Background technique

The current drive motors used in electric vehicles (including pure electric vehicles and hybrid vehicles) are generally AC asynchronous motors and permanent magnet synchronous motors. Although the AC asynchronous motor has simple structure and reliable operation, it has the inherent disadvantages of low power density and narrow constant power speed regulation range. At the same time, due to the copper loss of the rotor of the asynchronous motor, the heat generated by the rotor will be transmitted to the bearing, which will greatly The life of the bearing is reduced, which leads to the shortening of the overall life of the motor; although the permanent magnet synchronous motor has high efficiency, high power density, wide constant power speed regulation range and low rotor calorific value, it is generally dominated by permanent magnet torque. Its counter electromotive force is too high at high speed, and loss of control will damage the system, which is not conducive to the control of high-speed running of the vehicle. Therefore, it is necessary to develop a motor for driving electric vehicles with high efficiency, high power density, wide speed regulation range, low rotor calorific value, and no risk of back EMF damage to the system.

Synchronous reluctance motors have the advantages of high power density, wide speed range, high efficiency, and small size. However, due to the need to provide the performance of permanent magnets to provide motor performance, rare earth permanent magnets are often used, and rare earth permanent magnets are not renewable. , expensive, in order to save rare metal resources, reduce the environmental burden, and improve the performance and efficiency of the motor, the utility model proposes a new permanent magnet assisted permanent magnet synchronous motor and its rotor mechanism. High mechanical strength, low counter electromotive force, large salient pole ratio, and small torque fluctuation.

Utility model content

In order to overcome the deficiencies in the prior art, the utility model proposes a new motor using a synchronous reluctance structure, which solves the inherent defects of the existing permanent magnet synchronous motor and AC asynchronous motor, and compared with the existing synchronous reluctance Resistance motor, simple processing technology, large salient pole ratio, and small torque fluctuation.

In order to achieve the above object, the technical solution of the utility model is:

A motor using a synchronous reluctance structure, including a stator and a rotor, the stator includes a stator core and a winding, the rotor includes a rotor core, the rotor core is laminated by rotor punches, and the rotor punches include Several symmetrical magnetic poles, the magnetic poles are arranged alternately along the circumference of the rotor with N poles and S poles, the magnetic poles include a multi-layer grid, and the grid layer includes a plurality of grids. The relationship between the distance W between adjacent grids and the air gap δ between the stator and the rotor is: δ/3≤W≤3δ.

The magnetic poles include 3-4 layers of grids.

The grid layer includes 3-4 grids.

The magnetic steel is partially placed in the magnetic pole grid, and the rest is vacant.

Magnetic steel is placed in a part of the magnetic pole grid, and epoxy resin is placed in the rest.

The magnet is NdFeB magnet.

The relationship between the minimum distance A between adjacent magnetic poles and the rotor pole pitch T is: T/14≤A≤T/6.

The opening angle α formed by adjacent grids of adjacent magnetic poles ranges from 10° to 60°.

The stator winding is a distributed winding.

The motor using a synchronous reluctance structure is applied to a hybrid drive system.

Compared with the existing synchronous reluctance motor, the utility model has significant advantages and beneficial effects, which are embodied as follows:

1. Using the motor with synchronous reluctance structure of the utility model, it adopts the design of partially placing the magnets, which reduces the usage of magnets and saves costs;

2. Using the motor with synchronous reluctance structure of the utility model, the position of the grid and the distribution of the magnet steel are designed, which further improves the utilization rate of the reluctance torque and the efficiency of the motor;

Description of drawings

Fig. 1 is the schematic diagram of the first embodiment of the motor using the synchronous reluctance structure of the utility model;

Fig. 2 is a schematic diagram of the relationship between the number of grid layers, the salient pole ratio and the torque in the motor with synchronous reluctance structure applied in the present invention;

Fig. 3 is a schematic diagram of the relationship between the number of grids on the same layer and the ratio of salient poles and torque in the motor using the synchronous reluctance structure of the utility model;

Fig. 4 is a schematic diagram of the relationship between the distance between the adjacent grids of the same grid layer and the rotor shear stress and torque at the highest speed in the motor using the synchronous reluctance structure of the utility model;

Fig. 5 is a schematic diagram of the relationship between the minimum distance between adjacent magnetic poles and the salient pole ratio and torque in the motor using the synchronous reluctance structure of the present invention;

Fig. 6 is a schematic diagram of the relationship between the angle between adjacent magnetic pole grids and the ratio of salient poles and torque in the motor using the synchronous reluctance structure of the utility model;

Fig. 7 is a schematic diagram of the relationship between the grid spacing of two adjacent layers and the ratio of salient poles and torque in the motor using the synchronous reluctance structure of the present invention;

Fig. 8 is the schematic diagram of the relationship between the magnetic steel filling rate and the back EMF of the no-load line in the motor of the utility model application synchronous reluctance structure;

Fig. 9 is a schematic diagram of the second embodiment of the motor applying the synchronous reluctance structure of the present invention;

Fig. 10 is a schematic diagram of the third embodiment of the motor applying the synchronous reluctance structure of the present invention;

Fig. 11 is a schematic diagram of a fourth embodiment of a motor applying a synchronous reluctance structure according to the present invention.

Detailed ways

The concrete implementation method of the present utility model is as follows:

Existing permanent magnet synchronous motors mostly use expensive rare-earth permanent magnet materials, and the counter electromotive force generated by the distribution of permanent magnets is large; although synchronous reluctance motors can provide small counter electromotive force, but because the rotor does not use permanent magnets , so in the case of the same motor size, the power density of the synchronous reluctance motor is much smaller.

The synchronous reluctance motor rotor provided by the utility model has multiple sets of permanent magnet slots, and each set of permanent magnet slots includes a multi-layer grid. The so-called "grid" in this article refers to the slot-like structure set on the rotor core or the structure penetrating the rotor core in the axial direction, which is similar to the magnetic pole slot of the permanent magnet synchronous motor, but the grid can be filled or not filled with permanent magnets. magnetic material. Figure 1 is a schematic diagram of the rotor structure of the synchronous reluctance motor in the first embodiment of the utility model. The rotor core is formed by laminating the rotor punches. The rotor punches are composed of six symmetrical magnetic poles, and each magnetic pole is composed of a multi-layer grid. , after a large number of experiments and simulations, the influence of the number of grid layers of each magnetic pole on the output torque of the motor and the salient pole ratio of the motor is shown in Figure 2. The so-called "saliency ratio" in this article refers to the ratio of the motor's quadrature axis inductance to the direct axis inductance. In this embodiment, a 3-layer grid structure is selected, and each layer of grids is composed of several linear grids. In the structure shown in Figure 1, each layer of grids is set to more than 2 grids, and all grids have the same width. , there is the same spacing H between two adjacent grids, and the same spacing W between adjacent grids of each layer of grids, along the outer radius of the motor rotor from outside to inside, the first grid group consists of two The two grids are arranged in a straight line; if the size of the rotor allows, the first layer of grids can be composed of more than two grids, and the grids are not necessarily arranged in a straight line. The second layer and the Nth layer grid group inward from the first layer grid group are composed of two or more grids, and the angle between each two grids is less than 180 degrees. In this embodiment, the grid group of the second layer and the grid group of the third layer are respectively composed of three grids, and the grids of each layer of grid group form a U-shaped arrangement towards the outer edge of the rotor. If the process permits, each layer of grid groups may include 3 or more grids, and the grids are not limited to the same length. For the driving motor used in the automotive field, the influence of the number of grid layers of each magnetic pole on the output torque of the motor and the ratio of the salient poles of the motor is shown in Figure 2, and the number of grids of each layer of grid has an The influence of the salient pole ratio of the motor is shown in Figure 3. Therefore, considering the output torque of the motor and the salient pole ratio of the motor, it is better to choose 3 to 4 layers of grids, and each layer of grids contains 3 to 4 grids.

The motor rotor of the utility model is arranged in the form of alternating N poles and S poles along the circumferential direction, and the distance W between the grids in each grid layer also has a great influence on the mechanical strength and magnetic flux leakage control of the motor. The shear stress generally does not exceed 270Mpa. Once exceeded, the material is likely to break. The shear stress is the internal force per unit area at a certain point on the section under investigation, which is called stress, and the one that is tangent to the section is called shear stress or shear stress . The air gap of the motor δ=(D1-D2)/2, where D1 is the inner diameter of the stator, D2 is the outer diameter of the rotor, and the grid spacing W in each grid layer corresponds to the test of output torque and shear stress at the highest rotor speed The data is shown in Figure 4. From the data in the figure, it can be obtained that the grid spacing W of each layer should be δ/3～3δ. For the utility model embodiment 1, W is preferably δ～2δ, which can improve the mechanical strength of the rotor. , to ensure that it can withstand the centrifugal stress during high-speed rotation, and can also control the magnetic flux leakage at an acceptable small value. At the same time, compared with the arc structure, the processing technology of this structure is simpler and easier to operate.

In addition, the test data show that under the same magnetic steel condition, the ratio of the minimum spacing A between two adjacent magnetic poles to the rotor pole pitch T has a great influence on the salient pole ratio and output torque of the motor. In order to make the pole width A Increase to increase the magnetic flux and prevent magnetic saturation, and move the grid to the outer circumference of the rotor, but this will cause the magnetic steel to be far away from the inside of the rotor, thereby reducing the q-axis inductance, so the interpole width A cannot be too large. As shown in Figure 5, it can be obtained from the test data in the figure that when A is between T/14 and T/6, the inductance will not drop significantly due to the saturation between the poles of the permanent magnet, nor will it be caused by the magnetic steel in the rotor being too large. Close to the outer circumference of the rotor, the q-axis inductance drops rapidly. Therefore, the magnetic pole spacing A is selected as T/14~T/6, and the optimal choice is T/10~T/8. Increase the flux linkage of the motor and the difference between the d-axis inductance and the q-axis inductance without increasing the amount of stator copper wire, thereby increasing the salient pole ratio and output torque of the motor, which is helpful for reducing the copper loss of the motor and improving the motor's performance. The efficiency is very favorable, which can make the results of salient pole ratio and output torque optimal, and can also control the leakage flux at an acceptable smaller value.

The size of the angle α formed by the extension lines of the adjacent magnetic pole grids directly affects the distance between the motor rotor magnetic poles and the rotor center and the distance between the magnetic poles, thereby affecting the performance of the motor, such as the motor salient pole ratio and output torque. Adjacent The test results of the angle α formed by the extension line of the magnetic pole grid corresponding to the salient pole ratio and output torque of the motor are shown in Figure 6. From the data in the figure, it can be concluded that α should be selected from 10° to 60°, and the optimal choice is from 20° to 40°, the optimal effect of salient pole ratio and output torque can be guaranteed. Cooperate with distributed stator windings, the motor stator of the distributed windings has no convex pole palms, each magnetic pole is composed of one or several coils embedded and wired according to certain rules to form a coil group, and magnetic poles of different polarities are formed after electrification. To ensure that the fluctuation of the reluctance torque is small.

Combined with the design of the multi-layer permanent magnet structure of the motor rotor, the q-axis inductance of the synchronous reluctance motor can be rapidly increased, and the inductance difference between the q-axis and the d-axis can be increased as much as possible, and the utilization rate of the motor reluctance torque can be further improved. For the above purpose, the utility model designs and obtains the influence of the ratio of the distance H between the adjacent grid layers of each magnetic pole to the rotor pole pitch T on the salient pole ratio and output torque of the motor through simulation. Pole pitch"T=π*D1/(2p), where D1 is the inner diameter of the stator, and p is the number of pole pairs. The ratio of the spacing H between adjacent grid layers to the rotor pole pitch T corresponds to the specific test data of the salient pole ratio and output torque of the motor as shown in Figure 7. From the data in the figure, the spacing between each grid layer can be obtained The selection range of the ratio of H to the rotor pole pitch T is T/16~T/8, and T/12~T/10 is optimally selected. Cooperate with distributed stator windings, the motor stator of the distributed windings has no convex pole palms, each magnetic pole is composed of one or several coils embedded and wired according to certain rules to form a coil group, and magnetic poles of different polarities are formed after electrification. To ensure that the fluctuation of the reluctance torque is small.

In this embodiment, NdFeB magnets are used in conjunction with non-magnetic and non-conductive materials, and NdFeB magnets are placed in the middle section of the second and third layer grids, while other parts are left blank or placed with epoxy resin, etc. Non-magnetic and non-conductive materials greatly reduce the use of NdFeB magnets, save materials and reduce weight. At the same time, only part of the magnets are used in the entire magnetic circuit. How to select the filling amount of magnets also has a great influence on the performance of the motor. The test data of the filling rate of the magnets corresponding to the back EMF of the no-load line is shown in Figure 8, where the filling rate of the magnets is defined as the total width of the magnets / total grid slot Width, no-load line back EMF is defined as no-load line back EMF at rated speed. Generally, the maximum speed of electric vehicle drive motors is generally 2 to 3 times the rated speed. If the maximum speed off-line back EMF does not exceed the power supply voltage, the peak value of the no-load line back EMF/power supply voltage at the rated speed is 0.33 to 0.5, The preferred magnetic steel filling rate is 10% to 50%, and the optimal choice is 20% to 40%. This will make the motor performance take into account the advantages of permanent magnet motors and asynchronous motors, and at the same time avoid the disadvantages of permanent magnet motors and asynchronous motors. , it can not only ensure that the motor has higher efficiency and wider speed regulation range than the asynchronous motor, but also can ensure that the counter electromotive force at high speed is not large and will not exceed the power supply voltage, so as to ensure the normal operation of the motor.

In the magnetic circuit structure adopted by the synchronous reluctance motor rotor of the utility model, the ratio of the reluctance torque to the total torque is about 70%, the ratio of the permanent magnet torque to the total torque is about 30%, and the efficiency ratio is the same The efficiency of the first-class asynchronous motor is about 4 points higher, the speed regulation range can be from the rated speed to 2 times the rated speed, and its peak power can remain unchanged.

Fig. 9 is a schematic structural diagram of the second embodiment of the synchronous reluctance motor and its rotor of the present invention. In this embodiment, the magnetic steel is only filled in the layer closest to the center of the rotor.

Fig. 10 is a schematic structural diagram of the third embodiment of the synchronous reluctance motor and its rotor of the present invention. In this embodiment, the grid layer farthest from the center of the rotor is a three-stage structure.

Fig. 11 is a structural schematic diagram of the fourth embodiment of the synchronous reluctance motor and its rotor of the present invention. In this embodiment, the grid layer farthest from the center of the rotor is a three-section structure and the magnetic steel is only filled in the area closest to the center of the rotor. layer of .

As for the exemplary embodiments of the present utility model, it should be understood as one of the exemplary embodiments within the protection scope of the claims of the present utility model, and it has a guiding role for those skilled in the art to realize the corresponding technical solutions, Rather than limiting the utility model.

Claims (10)

1. A motor using a synchronous reluctance structure, comprising a stator and a rotor, the stator comprising a stator core and a winding, the rotor comprising a rotor core, characterized in that: the rotor core is laminated by rotor punches, The rotor punch includes several symmetrical magnetic poles, the magnetic poles are arranged alternately along the circumference of the rotor with N poles and S poles, the magnetic poles include a multi-layer grid, and the grid layer includes a plurality of grids. The relationship between the distance W between adjacent grids in each grid layer and the air gap δ between the stator and the rotor is: δ/3≤W≤3δ. 2 . The motor applying a synchronous reluctance structure according to claim 1 , wherein the magnetic poles comprise 3-4 layers of grids. 3 . The motor applying a synchronous reluctance structure according to claim 2 , wherein the grid layer comprises 3 to 4 grids. 4 . 4. The motor with synchronous reluctance structure according to claim 3, characterized in that: part of the magnetic pole grid is placed with magnetic steel, and the rest is vacant. 5 . The motor using a synchronous reluctance structure according to claim 4 , characterized in that: magnet steel is placed in a part of the magnetic pole grid, and epoxy resin is placed in the rest. 6 . The motor applying a synchronous reluctance structure according to claim 4 or claim 5 , wherein the magnet is NdFeB magnet. 7. The motor applying synchronous reluctance structure according to claim 1, characterized in that: the relationship between the minimum distance A between the adjacent magnetic poles and the rotor pole pitch T is: T/14≤A≤T /6. 8 . The motor applying a synchronous reluctance structure according to claim 1 , wherein the opening angle α formed by adjacent grids of adjacent magnetic poles ranges from 10° to 60°. 9. The motor applying synchronous reluctance structure according to claim 1, characterized in that: the stator winding is a distributed winding. 10. The motor applying a synchronous reluctance structure according to claim 1, characterized in that: the motor applying a synchronous reluctance structure is applied to a hybrid drive system.