Modularized fan-shaped rotor driving motor with non-uniform air gaps

Abstract

The invention relates to the technical field of driving motors for electric vehicles, in particular to a modular fan-shaped rotor driving motor with non-uniform air gaps, which comprises a stator, a three-phase winding, a rotor module and a rotor fixing frame, the rotor module comprises p magnetic poles, each magnetic pole is composed of a permanent magnet and a fan-shaped iron core, the outer edge of the fan-shaped iron core is composed of two sections of arcs, the permanent magnets are embedded in the center of the fan-shaped iron core, the permanent magnets are arranged in a spoke mode, and the p permanent magnets are magnetized in the tangential direction in the anticlockwise direction. The modular fan-shaped rotor structure with the non-uniform air gaps is adopted, so that inter-pole magnetic flux leakage of the permanent magnets is reduced, the air gap flux density waveform is improved, and daily overhaul and maintenance of the motor are more convenient; the permanent magnets are magnetized in the same direction to increase the number of pole pairs of the rotor and the number of magnetic flux loops, so that the magnetic barrier effect of a traditional spoke type motor is weakened, the torque pulsation of the motor is reduced, and the working efficiency of the motor is improved.

Description

Technical Field

[0001] The invention relates to the technical field of drive motors for electric vehicles, in particular to a modular fan-shaped rotor drive motor with a non-uniform air gap. Background Art

[0002] The development of new energy electric vehicles is an important measure to achieve low-carbon emission reduction, sustainable energy development, and promote industrial upgrading. The drive motor, as the power source of electric vehicles, has different design goals from traditional industrial motors. The current mainstream structure of new energy electric vehicle drive motors is mainly arranged with permanent magnets in "V" shape, "U" shape and variants of this type, and most of them are integral rotor structures. There are relatively few studies on spoke permanent magnet motors and block rotor electric vehicle drive motors. Compared with traditional "V" shaped permanent magnet synchronous motors, spoke permanent magnet motors have better magnetic concentration effects and can increase the air gap flux density to a certain extent. However, compared with other permanent magnet synchronous motors, spoke permanent magnet motors have poor air gap flux sinusoidality, large motor leakage coefficient and end and inter-pole leakage, and unstable torque output.

[0003] The Chinese patent application number CN201610174113.2 discloses a modular built-in permanent magnet motor rotor structure, including rotor sector modules and connectors. The rotor sector modules are laminated silicon steel sheets, and permanent magnets arranged in an "eight" shape are embedded in them. The modular rotors are spliced ​​together by connector snaps to form a circular rotor, which simplifies the production process and improves the utilization rate of permanent magnets and motor efficiency. However, the patent structure still uses a "V" shape arrangement for the permanent magnet arrangement, which limits the increase in the motor air gap magnetic flux amplitude and thus affects the increase in output torque.

[0004] The Chinese patent application number CN202110702440.1 discloses a highly mechanically robust magnetic field modulated radial permanent magnet motor and its multi-harmonic optimization design method. Specifically, it is a modulated spoke-like permanent magnet motor with an inverted T-shaped permanent magnet arrangement composed of a radial permanent magnet and a Halbach permanent magnet array. This structure utilizes the self-shielding effect of the Halbach permanent magnet array at the lower end to avoid the permanent magnetic field being closed in the rotor and realize the integrated processing of the rotor structure. However, due to the limitations of the integral salient pole rotor, the shielding effect of the Halbach permanent magnet array cannot be fully realized, and there is still a large amount of inter-pole leakage and end leakage.

[0005] The Chinese patent with patent application number CN202410758070.7 discloses an asymmetric modular spoke permanent magnet motor rotor, specifically a spoke permanent magnet motor with asymmetric rotor. The motor reduces the motor cogging torque and inter-pole magnetic leakage by breaking the modular rotor into two parts from the permanent magnet and making the two parts of the magnetic steel have different widths. However, since the rotor module of this motor is divided into multiple parts, the difficulty of processing is greatly increased, and the asymmetric structure often causes a large unbalanced magnetic pull.

[0006] In summary, the existing technologies are unable to improve the permanent magnet utilization rate and output torque quality of the spoke-type permanent magnet motor. Summary of the invention

[0007] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a modular fan-shaped rotor drive motor with a non-uniform air gap.

[0008] In order to solve the above technical problems, the present invention provides the following technical solutions: A modular sector-shaped rotor drive motor with a non-uniform air gap comprises a stator, a three-phase winding, a rotor module and a rotor fixing frame, wherein the rotor module comprises p magnetic poles, each magnetic pole consists of a permanent magnet and a sector-shaped iron core, the outer edge of the sector-shaped iron core consists of two circular arcs, the permanent magnet is embedded in the center of the sector-shaped iron core, the permanent magnet is arranged in a spoke-like form, and the p permanent magnets are all tangentially magnetized in a counterclockwise direction.

[0009] In the above structure, by adopting a modular rotor structure in which all rotor modules are identical, the rotor modules are independent of each other, which is conducive to the isolation of the magnetic circuit between the rotors, reducing the inter-pole leakage, and facilitating large-scale production and replacement and repair of damaged rotors. By adopting modular fan-shaped rotor modules, compared with salient pole modular rotors, the inter-pole leakage can be better reduced, and the amplitude of the high-order harmonics of the air gap flux generated by the double salient pole structure of the motor can be reduced, thereby effectively reducing the motor torque pulsation and improving the utilization rate of permanent magnets. In addition, by adjusting the outer edge of the fan-shaped rotor to be composed of two arcs to form a non-uniform air gap between the stator and the fan-shaped rotor, the inter-pole leakage caused by the excessive pole arc coefficient of the fan-shaped rotor can be further reduced, and the utilization rate of permanent magnets can be improved; at the same time, due to the existence of the non-uniform air gap, the magnetic field concentration effect of the rotor and the sinusoidal nature of the air gap flux waveform can be effectively improved, the output torque quality of the motor can be improved, and the operation can be more stable.

[0010] The magnetic flux generated by the permanent magnet in each rotor module passes from the N pole through the rotor N pole side, the air gap, the stator, the air gap, the rotor S pole side and back to its own S pole to form a magnetic flux loop; the magnetic flux loops generated by the p permanent magnets have the same direction, which is a clockwise loop.

[0011] In the above structure, by arranging the permanent magnets in a spoke-like manner and changing the traditional opposite magnetization to tangential and unidirectional magnetization of all permanent magnets, the ratio of the number of rotor pole pairs to the number of stator winding pole pairs can be effectively increased, the number of magnetic flux circuits can be increased, and the magnetic barrier effect that often exists in spoke-type motors can be weakened, which helps to increase the motor output torque and reduce motor losses and vibration amplitude.

[0012] The two arc sections on the outer edge of the sector-shaped core form a non-uniform air gap between the stator and the sector-shaped core. The air gap length at the central axis of the permanent magnet is the same as the air gap length at the left and right ends of the sector-shaped core and is the largest air gap. The air gap in the middle between the central axis of the permanent magnet and the two ends of the sector-shaped core is the smallest and is half of the maximum air gap.

[0013] Each of the rotor modules is bilaterally symmetrical along the central axis of the internal permanent magnet.

[0014] The angle from the center of the rotor as a whole to the widest position of the sector core is α = 260° / p~340° / p.

[0015] The stator is an integral stator with a trapezoidal pole shoe, and the three-phase winding adopts a centralized winding form, and the windings are wound with teeth between each other. The stator is arranged with fault-tolerant teeth of the same size, and each stator tooth has a trapezoidal pole shoe. The fault-tolerant teeth between the windings are provided to improve the fault-tolerant performance of the motor, reduce the influence of the phase-to-phase mutual inductance, realize the bipolar change of the magnetic flux, and share the electromagnetic load and thermal load.

[0016] Specifically, the tail of the sector core is set to be dovetail-shaped, the rotor fixing frame is made of non-magnetic material, and the rotor fixing frame is provided with dovetail grooves matching the dovetail structure of the rotor module. The rotor fixing frame fixes p rotor modules through the dovetail grooves to form a rotor as a whole.

[0017] The beneficial effects achieved by the present invention are: The present invention adopts a modular fan-shaped rotor structure with a non-uniform air gap to reduce the leakage flux between the permanent magnet poles, improve the air gap magnetic density waveform, and make the daily inspection and maintenance of the motor more convenient; the permanent magnets are magnetized in the same direction to increase the number of rotor pole pairs and the number of magnetic flux loops, thereby weakening the magnetic barrier effect existing in the traditional spoke motor, reducing the motor torque pulsation and improving the motor working efficiency; the stator is set with a fault tolerance scale to reduce the phase mutual inductance to a certain extent, improve the motor fault tolerance performance and share the electromagnetic load and heat load brought by the winding. Therefore, the present invention can improve the utilization rate of the permanent magnets and the output torque quality of the spoke permanent magnet motor.

[0018] The motor of the present invention has a lower no-load back electromotive force harmonic distortion rate, greatly reduces the inter-pole magnetic leakage of the permanent magnet, improves the air gap magnetic flux waveform, and increases the air gap fundamental wave amplitude, thereby reducing the torque pulsation and maximizing the output torque; and because of the modular rotor structure, the material density of the rotor fixing frame is often less than the density of the silicon steel sheet, thereby achieving light weight and high efficiency of the motor, and improving the efficiency and power density of the motor.

[0019] The modular rotor of the present invention results in a small proportion of the rotor core, which reduces the amount of silicon steel used, thereby controlling the cost; at the same time, because the rotor fixing frame is made of non-magnetic material, its material density is often less than the density of silicon steel, which is conducive to achieving light weight and high efficiency of the motor and improving the efficiency and power density of the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings: Figure 1 It is a structural schematic diagram of the present invention; Figure 2 It is a schematic diagram of a single rotor module of the present invention; Figure 3 It is a schematic diagram of winding connection of the present invention; Figure 4 It is a schematic diagram comparing the output torques of a conventional spoke-type permanent magnet motor of the same size and the motor of the present invention; Figure 5 It is a schematic diagram comparing the no-load air gap flux density waveforms of a conventional spoke-type permanent magnet motor of the same size and the motor of the present invention; Figure 6 It is a schematic diagram of the structure of the present invention (with the annotation of angle α added).

[0021] In the figure: 1. stator; 2. three-phase winding; 3. rotor module; 4. rotor fixing frame; 31. sector core; 32. permanent magnet. DETAILED DESCRIPTION

[0022] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0023] Example: like Figure 1 , Figure 2 As shown, a modular sector rotor drive motor with a non-uniform air gap includes a stator 1, a three-phase winding 2, a rotor module 3 and a rotor fixing frame 4.

[0024] The rotor module 3 includes p magnetic poles, each of which is composed of a permanent magnet 32 ​​and a sector core 31. Each rotor module 3 is bilaterally symmetrical along the central axis of the internal permanent magnet 32. The outer edge of the sector core 31 is composed of two arcs, and the permanent magnet 32 ​​is embedded in the center of the sector core 31. This type of rotor can effectively reduce inter-pole leakage and no-load back electromotive force harmonic distortion, optimize the air gap magnetic density waveform, and improve the utilization rate of the permanent magnet 32, thereby improving the size and quality of the output torque.

[0025] The permanent magnet 32 ​​is rectangular in shape, and is arranged in a spoke-like manner, and the p permanent magnets 32 are all magnetized tangentially in a counterclockwise direction. The magnetization directions of the permanent magnets 32 are consistent, and this arrangement can form more magnetic flux loops with the same amount of permanent magnets 32, which helps to increase the motor output torque, reduce vibration, and make the motor run more smoothly.

[0026] Specifically, the magnetic flux generated by the permanent magnet 32 ​​in each of the rotor modules 3 passes through the N pole side of the rotor, the air gap, the stator 1, the air gap, the S pole side of the rotor and returns to its own S pole, forming a magnetic flux loop; the directions of the magnetic flux loops generated by the p permanent magnets 32 are the same, which is a clockwise loop.

[0027] The two arc sections on the outer edge of the sector core 31 constitute a non-uniform air gap between the stator 1 and the sector core 31. The air gap length at the central axis of the permanent magnet 32 ​​is the same as the air gap length at the left and right ends of the sector core 31 and is the largest air gap. The air gap at the middle position between the central axis of the permanent magnet 32 ​​and the two ends of the sector core 31 is the smallest and is half of the maximum air gap.

[0028] like Figure 6 As shown, the angle from the center of the rotor as a whole to the widest position of the sector core 31 is α=260° / p~340° / p.

[0029] The tail of the sector core 31 is set to be in a dovetail shape, and the rotor fixing frame 4 is made of non-magnetic material. The rotor fixing frame 4 is provided with a dovetail groove that matches the dovetail structure of the rotor module 3. The rotor fixing frame 4 fixes the p rotor modules 3 through the dovetail groove to form a rotor as a whole.

[0030] The stator 1 is an integral stator with a trapezoidal pole shoe, and the three-phase winding 2 is a centralized winding, with the windings wound with teeth spaced apart. The stator 1 is provided with fault-tolerant teeth of the same size, and each stator tooth has a trapezoidal pole shoe. Figure 3 The figure shows a three-phase centralized winding connection diagram of the present invention. Taking the rightmost tooth in the horizontal direction of the rotor as the reference, the slot numbers 1-24 are assigned in sequence in a clockwise direction. It can be seen from the figure that in this winding method, only one stator tooth between adjacent stator teeth is wound with a winding, so it can effectively share the electromagnetic load and thermal load and reduce the mutual inductance between phases.

[0031] like Figure 4 The figure shows a comparison of the output torque of a modular fan-shaped rotor drive motor with a non-uniform air gap of the present invention and a traditional spoke-type permanent magnet motor. The above-mentioned rotor module 3 structure is combined with a unique stator form and winding method, so that the output torque of the motor of the present invention is improved by 9.3% and the torque pulsation is reduced by 41.8%.

[0032] like Figure 5 The figure shows a schematic diagram of the comparison of the no-load air gap flux waveform of a modular fan-shaped rotor drive motor with a non-uniform air gap and a traditional spoke-type permanent magnet motor. From the number of air gap flux peaks in the figure, it can be seen that the air gap flux has a higher amplitude and better air gap flux sinusoidality after combining the same-direction magnetization with the modular rotor with a non-uniform air gap, and the number of peaks increases from five to ten, that is, the number of flux loops doubles. Higher air gap flux amplitude and sinusoidality and more flux loops are conducive to generating higher output torque and lower torque pulsation, making the motor run more smoothly.

Claims

1. A modular sector rotor drive motor with non-uniform air gap, characterized in that: The invention comprises a stator (1), a three-phase winding (2), a rotor module (3) and a rotor fixing frame (4), wherein the rotor module (3) comprises p magnetic poles, each magnetic pole being composed of a permanent magnet (32) and a sector-shaped iron core (31), the outer edge of the sector-shaped iron core (31) being composed of two circular arcs, the permanent magnet (32) being embedded in the center of the sector-shaped iron core (31), the permanent magnet (32) being arranged in a spoke-like manner, and the p permanent magnets (32) are all tangentially magnetized in a counterclockwise direction.

2. The modular sector rotor drive motor with non-uniform air gap according to claim 1, characterized in that: The magnetic flux generated by the permanent magnet (32) in each rotor module (3) passes from the N pole in sequence through the rotor N pole side, the air gap, the stator (1), the air gap, the rotor S pole side and returns to its own S pole, forming a magnetic flux loop; the magnetic flux loops generated by the p permanent magnets (32) have the same direction, that is, a clockwise loop.

3. The modular sector rotor drive motor with non-uniform air gap according to claim 1, characterized in that: Two arc sections on the outer edge of the sector-shaped core (31) form a non-uniform air gap between the stator (1) and the sector-shaped core (31); the air gap length at the central axis of the permanent magnet (32) is the same as the air gap lengths at the left and right ends of the sector-shaped core (31) and is the largest air gap; the air gap is the smallest at the middle between the central axis of the permanent magnet (32) and the two ends of the sector-shaped core (31) and is half of the largest air gap.

4. The modular sector rotor drive motor with non-uniform air gap according to claim 1, 2 or 3, characterized in that: Each of the rotor modules (3) is bilaterally symmetrical along the central axis of the internal permanent magnet (32).

5. The modular sector rotor drive motor with non-uniform air gap according to claim 1, 2 or 3, characterized in that: The angle from the center of the rotor as a whole to the widest position of the sector core (31) is α=260° / p~340° / p.

6. The modular sector rotor drive motor with non-uniform air gap according to claim 1, characterized in that: The three-phase winding (2) adopts a concentrated winding form, and the windings are wound with teeth spaced apart.

7. The modular sector rotor drive motor with non-uniform air gap according to claim 1, characterized in that: The stator (1) is provided with fault-tolerant teeth of the same size, and each stator tooth is provided with a trapezoidal pole shoe.

8. The modular sector rotor drive motor with non-uniform air gap according to claim 1, characterized in that: The tail of the sector core (31) is arranged in a dovetail shape, the rotor fixing frame (4) is made of a non-magnetic material, a dovetail groove matching the dovetail structure of the rotor module (3) is provided on the rotor fixing frame (4), and the rotor fixing frame (4) fixes the p rotor modules (3) via the dovetail groove to form a rotor as a whole.

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