CN108988598B - Magnetic flux modulation type permanent magnet vernier motor with built-in stator - Google Patents

Abstract

The invention discloses a permanent magnet vernier motor with a built-in magnetic flux modulation in the stator, which is arranged inside the motor casing and is sequentially arranged with an outer rotor (2), an inner rotor (3) and a stator (4) from the outside to the inside, and the outer rotor is arranged in sequence from the outside to the inside. 2. There are twelve outer rotor salient poles (2‑1) on the inner surface, eight inner rotor salient poles (3‑1) on the outer surface of the inner rotor (3) near the outer rotor side, and the inner surface near the stator side is It has a circular surface structure and is embedded with sixteen pairs of permanent magnets (3‑2). The stator (4) is connected to the casing (1) by an iron block (13). There are six stator teeth (4‑1) on the circumference of the stator iron core. And three magnetic flux modulation poles (4-2) are placed on each stator tooth, and three-phase centralized stator armature windings (6) and DC excitation windings (7) with two pairs of pole pairs are placed in the stator slots at the same time. The advantages of the invention are: the torque output capability, torque density, speed regulation range and mechanical strength are increased, and the processing and assembly are simple.

Description

A permanent magnet vernier motor with built-in magnetic flux modulation in the stator

technical field

The invention belongs to the field of hybrid electric vehicles, in particular to a permanent magnet vernier motor with built-in magnetic flux modulation in a stator.

Background technique

With the crisis of energy depletion and the increasingly serious environmental pollution problems, hybrid vehicles, as a transitional product of traditional internal combustion engine vehicles and pure electric vehicles, have become the focus of current research. As an electromechanical energy conversion device in a hybrid vehicle, the performance of the motor drive system will directly affect the quality of the entire vehicle. For this reason, those skilled in the art provide motor drive systems with different structures.

"Design and Research of New Type External Rotor Magnetic Gear Composite Motor", Zhang Dong et al., Chinese Journal of Electrical Engineering Vol. 28 No. 30, pp. 67-72, October 25, 2008 A new external rotor magnetic gear composite motor was recorded The motor, which integrates a high-speed brushless DC motor with an outer rotor and a magnetic gear to form a composite motor, realizes a direct drive mode with low speed and high torque. The disadvantage is that the outer rotor magnetic gear composite motor has three layers of air gaps, which leads to complex structure, mutual coupling of magnetic fields, and complex magnetic field distribution, which makes the analysis of the motor difficult. At the same time, the modulation ring is composed of alternating magnetic conductive blocks and non-magnetic conductive blocks, and is in the form of laminations, resulting in poor mechanical strength and difficult processing.

SUMMARY OF THE INVENTION

In view of the problems existing in the prior art, the technical problem to be solved by the present invention is to provide a permanent magnet vernier motor with a built-in magnetic flux modulation in the stator, which can increase the torque output capability, torque density, speed regulation range and mechanical strength , and the processing and assembly are simple.

The technical problem to be solved by the present invention is achieved through such a technical solution, which includes a motor casing, inside the motor casing, an outer rotor, an inner rotor and a stator are sequentially arranged from the outside to the inside, and the inner surface of the outer rotor has twelve The outer rotor salient pole, the three-phase centralized outer rotor armature winding is placed in the outer rotor slot; the outer surface of the inner rotor close to the outer rotor side has eight inner rotor salient poles, and the inner surface close to the stator side is a circular structure, and Sixteen pairs of permanent magnets are embedded, and the permanent magnets are magnetized in the radial direction and the magnetization directions of the adjacent permanent magnets are opposite; the stator is connected to the casing by an iron block, and the stator includes a stator iron core with a stator slot, and the circumference of the stator iron core has There are six stator teeth, and three magnetic flux modulation poles are placed on each stator tooth. The stator slot is a constricted hole slot. Three-phase centralized stator armature winding and DC excitation winding are placed in the stator slot at the same time, and the three-phase concentrated The number of pole pairs of the stator armature winding is two pairs, and the number of pole pairs of the DC excitation winding is two pairs.

The outer rotor and the salient poles of the inner rotor constitute a double salient outer motor; the permanent magnets on the inner surface of the inner rotor and the stator constitute a magnetic flux modulation type vernier inner motor.

Compared with the external rotor magnetic gear composite motor in the background technology, the technical effects of the present invention are:

The invention solves the problem of poor mechanical strength of the device caused when the modulation ring is placed alone by adding a magnetic flux modulation pole on the stator teeth, which is equivalent to making the modulation ring and the stator iron core into one body. The magnetic field modulation pole can modulate the air-gap permeance of the inner motor, change the winding inductance, generate reluctance torque to increase the torque output capability of the inner motor, improve the total output torque of the present invention, and also increase the torque density. At the same time, the number of motor components is reduced from 4 to 3, and the air gap of the motor is reduced from 3 layers to 2 layers, which reduces the volume of the motor device, reduces the difficulty of processing and production, and improves the practicability of the device. The external motor adopts double salient pole structure, which has the advantages of simple structure and manufacturing process, strong body, strong fault tolerance, large starting torque, wide speed regulation range and high running speed. Three-phase centralized stator armature windings and DC excitation windings are placed in the inner motor at the same time. By adjusting the magnitude and polarity of the excitation winding current, the speed regulation range of the inner motor is increased. In addition, the three-phase centralized outer rotor armature windings and the three-phase centralized stator armature windings in the present invention are both concentrated windings, which can reduce the amount of copper used in the motor and the copper loss of the motor, and also facilitate production and assembly wiring.

Therefore, the present invention has the advantages of increased torque output capability, torque density, speed regulation range and mechanical strength, and simple processing and assembly.

Description of drawings

The accompanying drawings of the present invention are described as follows:

1 is a structural diagram of a drive system of the present invention applied to a hybrid vehicle;

Figure 2 is a cross-sectional view of the present invention.

In the figure: 1. Motor shell; 2. Outer rotor; 2-1. Salient pole of outer rotor; 3. Inner rotor; 3-1. Salient pole of inner rotor; 3-2. Permanent magnet; 4. Stator; 4- 1. Stator teeth; 4-2. Magnetic flux modulation pole; 5. Three-phase centralized outer rotor armature winding; 6. Three-phase centralized stator armature winding; 7. DC excitation winding; 8. Double salient external motor ; 9. Magnetic flux modulation vernier motor; 10. Internal combustion engine; 11. Battery; 12. Main reducer; 13. Iron block; 14. Brush slip ring; 15. AC-DC rectifier; 16. DC-AC inverter Inverter; 17. Outer motor air gap; 18. Inner motor air gap.

Detailed ways

Below in conjunction with accompanying drawing and embodiment, the present invention will be further described:

As shown in Figures 1 and 2, the present invention includes a motor casing 1. Inside the motor casing, an outer rotor 2, an inner rotor 3 and a stator 4 are sequentially arranged from outside to inside. The inner surface of the outer rotor 2 has twelve outer rotors. Rotor salient pole 2-1, three-phase centralized outer rotor armature winding 5 is placed in the outer rotor slot; inner rotor 3 includes iron core and permanent magnet 3-2, and there are eight inner rotors on the outer surface of inner rotor 3 near the outer rotor side The salient pole 3-1 has a circular structure on the inner surface of the side close to the stator, and is embedded with sixteen pairs of permanent magnets 3-2. The permanent magnets 3-2 are magnetized in the radial direction and the magnetizing directions of the adjacent permanent magnets are opposite; The stator 4 is connected to the casing 1 by the iron block 13, which plays a fixed role. The stator includes a stator iron core with stator slots. The circumference of the stator iron core has six stator teeth 4-1, and three pieces are placed on each stator tooth. Magnetic flux modulation pole 4-2, magnetic flux modulation pole 4-2 is a magnetically permeable material, which is alternately arranged with air (non-magnetically permeable material) in the circumferential direction, which is equivalent to a modulation ring and stator core made of one piece; stator slots The three-phase centralized stator armature winding 6 and the DC excitation winding 7 are placed in the stator slot at the same time, and the number of pole pairs of the three-phase centralized stator armature winding 6 is two pairs, and the pole pairs of the DC excitation winding are The logarithm is two pairs.

According to "Analysis of Electromagnetic Performance of Variable Reluctance Controlled Flux Permanent Magnet Vernier Motor", Zhong Xu et al., Motor Control and Application, 2018, 45(6), 62-67, records the number of pole pairs of each part of the permanent magnet vernier motor. quantitative relationship. Therefore, the number of pole pairs of the three-phase centralized stator armature winding of the present invention, the number of stator teeth, the number of magnetic flux modulation poles, and the number of permanent magnet pole pairs can all be changed. The conditions they should meet are: the number of stator teeth * the number of magnetic flux modulation poles= Three-phase centralized stator armature winding pole pairs + permanent magnet pole pairs (such as 6*3=2+16).

As shown in FIG. 1 , the present invention is applied to the drive system of the hybrid vehicle: the output shaft of the internal combustion engine 9 drives the outer rotor 2, and a part of the mechanical power of the internal combustion engine 10 is transferred to the inner rotor 3 through the outer motor air gap 17 by means of electromagnetic energy conversion, The inner rotor 3 is connected with the main reducer 12 of the hybrid electric vehicle, and then directly drives the hybrid electric vehicle; the remaining output power is converted into electric power by the three-phase centralized outer rotor armature winding 5, and the brush slip ring structure 14 directly flows into the inner motor. The three-phase centralized stator armature windings 6 or flow into the AC-DC rectifier 15 and are converted into direct current to charge the battery 11 .

The inner rotor 3 is connected to the final reducer 12 of the hybrid vehicle, and the total output torque of the inner rotor 3 drives the vehicle to travel. The composition of the total output torque is: a. The above-mentioned electromagnetic torque generated by the electromagnetic energy transmitted from the outer motor air gap 17 to the inner rotor 3; b. The electromagnetic torque generated by the three-phase centralized stator armature winding 6 passes through the inner rotor. The motor air gap 18 is transmitted to the inner rotor 3, and the magnitude of the stator armature magnetic field can be adjusted to change the transmitted torque; c. When the torques transmitted to the inner rotor 3 by a and b are superimposed and still cannot meet the vehicle demand torque , the battery 11 starts to work, and the stored electric energy is converted by the DC-AC inverter 16 and input into the three-phase centralized stator armature winding 6, which also generates electromagnetic torque and transmits it to the inner rotor 3 to compensate for the required torque.

The working principle of the present invention is:

The permanent magnets 3-2 on the inner surface of the inner rotor of the present invention and the stator 4 constitute a magnetic flux modulation type vernier motor 9, which is a permanent magnet vernier motor based on the "magnetic field modulation principle". According to "Overview of the Development of Magnetic Gears", Fu Xinghe et al., Chinese Journal of Electrotechnical Technology, No. 18, 2016, pp. 1-12, in Section 2.1.2, it was recorded that the magnet-adjusting block can modulate the air-gap magnetic field and make full use of the harmonic The wave magnetic field can generate a constant effective torque. The magnetic field modulation pole installed on the surface of the stator teeth modulates the air-gap permeance of the inner motor, thereby changing the inductance of the stator armature winding, so that a small change in the rotor position can bring about a large change in the magnetic flux. The stator tooth pitch of the magnetic flux modulation vernier inner motor 9 is not equal to the tooth pitch of the inner rotor salient poles. A small position movement of the inner rotor 3 can bring about a large air gap permeability change. The stator teeth 4-1 and the inner rotor The salient pole 3-1 is similar to the upper and lower graduations of a vernier caliper.

The electromagnetic torque of the magnetic flux modulation vernier motor 9 consists of three parts: (1) the permanent magnet torque component generated by the action of the permanent magnet 3-2 and the three-phase centralized stator armature winding 6 current; (2) three The reluctance torque component generated by the inductance change of the phase-centralized stator armature winding 6; (3) the torque component generated by the interaction between the DC excitation winding 7 and the three-phase centralized stator armature winding 6.

When the magnetic flux modulation vernier motor 9 runs at low speed, the DC excitation winding does not apply excitation current, and the magnetic flux modulation effect of the magnetic field modulation pole is used to modulate the magnetic field of the three-phase centralized stator armature winding 6 with low pole pairs. Obtain the harmonic magnetic field component that can match the multi-pole-pair permanent magnet magnetic field, adjust the air-gap permeance, and change the inductance of the three-phase centralized stator armature winding to generate reluctance torque, thereby increasing the internal motor. total output torque.

According to "Field Weakening Control of Built-in Permanent Magnet Synchronous Motors for Electric Vehicles", Yu Yingchao, Master Thesis of Qingdao University of Science and Technology, pp. 29-34, June 2017, it was recorded that by increasing the negative stator d-axis current amplitude, the Weakening the permanent magnet excitation magnetic field to achieve the purpose of weak magnetic field expansion. The present invention utilizes the DC excitation magnetic field generated by the DC excitation winding to adjust the permanent magnet excitation magnetic field, and realizes the weak field speed expansion, and the details are as follows:

When the magnetic flux modulated vernier motor 9 runs at high speed, the DC excitation winding 7 and the permanent magnets 3-2 are placed in the stator slot to form a mixed excitation source, and the two work together to generate a DC excitation magnetic field, which is in the opposite direction to the permanent magnet magnetic field. At the same time, the permanent magnet magnetic field in the air gap of the inner motor is weakened, and the permanent magnetic field in the air gap of the inner motor is strengthened when the direction is the same. By adjusting the magnitude and polarity of the DC excitation current, the magnetic field adjustment function is realized to achieve high-speed field weakening control operation.

The outer rotor 2 and the inner rotor salient poles 3-1 of the present invention form a double salient pole outer motor 8, which has strong fault tolerance and simple structure and manufacturing process. Under the premise of ensuring that the internal combustion engine 10 always runs in the high-efficiency region, the rotational speed of the armature reaction magnetic field is adjusted by changing the current frequency of the three-phase centralized outer rotor armature winding 5 to adjust the rotational speed of the inner rotor, so as to meet the rotational speed requirements of the vehicle and reduce fuel consumption. consumption and exhaust emissions.

To sum up, the present invention has the following technical effects:

1. The present invention adds magnetic flux modulation poles on the stator teeth, which is equivalent to integrating the modulation ring with the stator core, which solves the problem of poor mechanical strength of the device caused by the modulation ring being placed alone, and improves the performance of the entire motor device. practicality. The magnetic flux modulation is used to realize the modulation of the air-gap permeance of the motor, so as to realize "self-deceleration", and finally make the motor work in low-speed and high-torque conditions.

2. Compared with the motor in the background technology, the present invention integrates the magnetic control ring with the conventional motor stator, and reduces the number of motor components to three and also reduces the air gap by one layer under the effect of ensuring the realization of magnetic flux modulation. The air gap of the motor is changed to 2 layers, which can reduce the size of the device and reduce the difficulty of processing and production. At the same time, the permanent magnets are embedded in the inner rotor core, which can further reduce the volume of the device.

3. In the present invention, three-phase centralized stator armature windings and DC excitation windings are placed in the stator of the inner motor at the same time, and the magnetic flux adjustment function is realized by adjusting the magnitude and polarity of the current of the excitation winding, and the magnetic flux generated by the inner motor is controlled to increase the speed range.

4. The external motor of the present invention is a double salient motor, which has the advantages of simple structure and manufacturing process, firm body, strong fault tolerance, large starting torque, wide speed regulation range and high running speed, and is suitable for different road conditions.

5. The three-phase centralized outer rotor armature winding and the three-phase centralized stator armature winding are all in the form of concentrated winding, which can effectively reduce the length of the armature winding end, thereby greatly reducing the amount of copper used in the motor and the copper loss of the motor ; The three-phase winding coils are separated independently, and there is no contact between the ends, which provides convenience for the modular production and assembly wiring of the windings.

Claims (1)

1. A flux modulation type permanent magnet vernier motor with a built-in stator comprises a motor shell (1), wherein an outer rotor (2), an inner rotor (3) and a stator (4) are sequentially arranged inside the motor shell from outside to inside, twelve outer rotor salient poles (2-1) are arranged on the inner surface of the outer rotor (2), and a three-phase centralized outer rotor armature winding (5) is arranged in an outer rotor slot; the method is characterized in that: the outer surface of the inner rotor (3) close to the outer rotor side is provided with eight inner rotor salient poles (3-1), the inner surface of the inner rotor (3) close to the stator side is of a circular surface structure, sixteen pairs of permanent magnets (3-2) are embedded, the permanent magnets (3-2) are magnetized along the radial direction, and the magnetizing directions of the adjacent permanent magnets are opposite; the stator (4) is connected to the casing (1) through an iron block (13), the stator comprises a stator core with stator slots, six stator teeth (4-1) are arranged on the circumference of the stator core, three magnetic flux modulation poles (4-2) are placed on each stator tooth, the stator slots are of a reduced hole type, three-phase centralized stator armature windings (6) and a direct current excitation winding (7) are placed in the stator slots at the same time, the number of pole pairs of the three-phase centralized stator armature windings (6) is two, and the number of pole pairs of the direct current excitation winding is two.

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