A high torque density multiphase permanent magnet Vernier motor with strong fault tolerance

Abstract

The application discloses a strong fault-tolerant high-torque-density multiphase permanent magnet vernier motor, and belongs to the field of fault-tolerant motors. The strong fault-tolerant high-torque-density multiphase permanent magnet vernier motor comprises a rotor, a stator and two sets of three-phase windings arranged on the stator. The stator comprises a stator core and stator teeth arranged on the stator core in a circumferential direction. One or more slots are arranged at the tooth tips of the stator teeth, so that a plurality of auxiliary teeth are formed at the tooth tips of the stator teeth. A slot is arranged at the middle upper part of the stator teeth, so that two fault-tolerant teeth are formed at the middle upper part of the stator teeth, and coils are wound on the fault-tolerant teeth. The stator teeth and the two coils wound thereon constitute a fault-tolerant unit. The two coils in the same fault-tolerant unit are located in the two sets of three-phase windings respectively, and the current amplitude and phase of the two windings in the same fault-tolerant unit are the same during operation. The structure of the stator and the winding arrangement mode are improved, so that the problem of mismatch between high back electromotive force and low impedance of a short circuit loop is solved, and the fault-tolerant performance of the high-torque-density permanent magnet vernier motor is improved.

Description

Technical Field

[0001] This invention belongs to the field of fault-tolerant motors, and more specifically, relates to a highly fault-tolerant, high torque density multiphase permanent magnet vernier motor. Background Technology

[0002] Drive motors in aerospace, new energy vehicles, and intelligent industrial manufacturing are facing greater challenges and technological changes. High power density and high torque density have become core technical indicators. Permanent magnet motors, due to their superior electromagnetic properties such as high power density, low moment of inertia, and fast dynamic response, are rapidly replacing traditional electrically excited motors and are being widely used. In particular, a type of field-modulated motor with unequal stator and rotor pole pairs has received more attention. By modulating the air gap magnetic permeability, a low-speed, multi-pole excitation magnetomotive force is generated on the stator to form a low-pole, high-speed magnetic field, equivalent to a combination of a high-speed permanent magnet motor and a magnetic gearbox, resulting in ultra-high torque density. The vernier permanent magnet motor is a typical example of such a field-modulated motor.

[0003] To further improve the torque density of permanent magnet vernier motors, excitation-enhanced and modulation-enhanced topologies have been proposed. Alternating pole, tangential excitation, and built-in structures are constantly emerging. Their torque density enhancement mechanism mostly involves increasing the no-load back EMF. However, increasing the no-load back EMF leads to a larger no-load flux linkage in the motor's turns. After an inter-turn short-circuit fault occurs, the high back EMF and low impedance mismatch in the short-circuit loop leads to a decrease in fault tolerance. Among various types of short-circuit faults, inter-turn short-circuit faults have the highest probability of occurrence. Especially for short-turn short-circuit loops with few turns, the impedance is very small, exacerbating the mismatch with the high no-load back EMF and resulting in extremely high short-circuit loop current. Therefore, effectively suppressing inter-turn short-circuit faults is crucial for improving the reliability of permanent magnet vernier motors.

[0004] However, current topologies for suppressing inter-turn short-circuit current in permanent magnet vernier motors are scarce. Most methods rely on physical isolation, such as fractional-slot concentrated windings and auxiliary teeth, to prevent inter-turn short-circuit faults. Patent application CN105958762A discloses a novel high-torque-density, high-power-factor-tolerant permanent magnet vernier motor and its modulation method, such as... Figure 1As shown, I represents the high torque density, high power factor, fault-tolerant permanent magnet vernier motor; I-1 is the inner stator; I-2 is the inner rotor; I-3 is the outer rotor; I-4 is the radial permanent magnet; I-5 is the surface-mounted permanent magnet; I-6 is the armature tooth; I-7 is the fault-tolerant tooth; and I-8 is the modulation tooth. Through the effective combination of the vernier motor and magnetic gears, the motor's torque output capability is enhanced and its efficient utilization is achieved. The use of concentrated windings and fault-tolerant teeth improves physical isolation and provides a certain degree of fault tolerance. However, while this scheme reduces the possibility of inter-turn short-circuit faults at the physical level, windings located in the same slot can still experience inter-turn short-circuit faults, and this topology cannot effectively suppress inter-turn short-circuit currents when such faults occur. Summary of the Invention

[0005] To address the shortcomings and improvement needs of existing technologies, this invention provides a highly fault-tolerant, high-torque-density multiphase permanent magnet vernier motor. The purpose is to propose a new permanent magnet vernier motor topology by improving the stator structure and winding arrangement to solve the problems of high back EMF and low impedance mismatch in short-circuit circuits, thereby improving the fault-tolerant performance of the high-torque-density permanent magnet vernier motor.

[0006] To achieve the above objectives, according to one aspect of the present invention, a highly fault-tolerant, high torque-density multiphase permanent magnet vernier motor is provided, comprising:

[0007] Rotor, stator, and two sets of three-phase windings installed on the stator;

[0008] The stator includes: a stator core, and stator teeth arranged circumferentially on the stator core; one or more slots are provided at the tips of the stator teeth to form multiple auxiliary teeth at the tips of the stator teeth; a slot is provided in the upper middle part of the stator teeth to form two fault-tolerant teeth in the upper middle part of the stator teeth, and coils are wound on the fault-tolerant teeth.

[0009] The stator teeth and the two coils wound on them constitute a fault-tolerant unit. The two coils in the same fault-tolerant unit are located in two sets of three-phase windings respectively. When working, the current amplitude and phase of the two windings in the same fault-tolerant unit are the same.

[0010] In one configuration, the rotor is located inside the stator, and the stator teeth are located inside the stator core; or, the rotor is located outside the stator, and the stator teeth are located outside the stator core.

[0011] Furthermore, there are unequal tooth pitches between all auxiliary teeth.

[0012] Furthermore, the number P of modulation blocks f Stator pole pair number P a and the number of rotor pole pairs P r Satisfy P a +P r=P f .

[0013] Furthermore, the stator adopts a fractional-slot concentrated winding.

[0014] In some alternative embodiments, the tips of the stator teeth are C-shaped.

[0015] In some alternative embodiments, the tips of the stator teeth are E-shaped.

[0016] According to another aspect of the present invention, a new energy vehicle is provided, wherein the drive motor is a high-torque-density multiphase permanent magnet vernier motor with strong fault tolerance provided by the present invention.

[0017] In summary, the above-described technical solutions conceived in this invention can achieve the following beneficial effects:

[0018] (1) The permanent magnet vernier motor provided by this invention has slots at the tips of its stator teeth, forming multiple auxiliary teeth. This effectively increases the number of harmonics in the motor's operation, improves the no-load back EMF, and gives the motor high torque density. Simultaneously, slots are provided in the upper middle part of the stator teeth, forming two fault-tolerant teeth. The coils on these two fault-tolerant teeth are located in two sets of three-phase windings, and the current amplitude and phase are the same. When the motor is running healthily, the magnetomotive forces on the two fault-tolerant teeth cancel each other out, preventing the formation of a ring-shaped leakage flux. However, when an inter-turn short-circuit fault occurs, the magnetomotive forces on the two fault-tolerant teeth cannot cancel each other out, forming a ring-shaped leakage flux around the stator teeth. Due to the high permeability of the iron core, this ring-shaped leakage inductance is large, significantly increasing the impedance of the short-circuit loop, thereby effectively suppressing the short-circuit current and improving the motor's fault-tolerant performance. In summary, the permanent magnet vernier motor provided by this invention simultaneously possesses high torque density and inter-turn short-circuit current suppression capabilities.

[0019] (2) When a single-phase short circuit fault occurs in one of the three-phase windings of the permanent magnet vernier motor provided by the present invention, the stator teeth where the coil of that phase is located will have annular leakage flux, thereby increasing the impedance on the single-phase short circuit circuit. Therefore, the permanent magnet vernier motor provided by the present invention also has a strong suppression effect on single-phase short circuit current. Attached Figure Description

[0020] Figure 1 A schematic diagram of an existing high torque density, high power factor fault-tolerant permanent magnet vernier motor;

[0021] Figure 2 This is a schematic diagram of a high-torque-density multiphase permanent magnet vernier motor with strong fault tolerance provided in an embodiment of the present invention;

[0022] Figure 3 This is a flux linkage distribution diagram of a permanent magnet vernier motor under inter-turn short-circuit fault provided in an embodiment of the present invention;

[0023] Figure 4 This is a flux linkage distribution diagram of a permanent magnet vernier motor under a single-phase short-circuit fault, provided in an embodiment of the present invention.

[0024] Figure 5 A comparison diagram of the short-circuit current of a permanent magnet vernier motor provided in an embodiment of the present invention and an existing permanent magnet vernier motor under the same short-circuit fault;

[0025] In all the accompanying drawings, the same reference numerals are used to denote the same elements or structures, wherein:

[0026] I represents the existing high torque density, high power factor fault-tolerant permanent magnet vernier motor; I-1 is the inner stator, I-2 is the inner rotor, I-3 is the outer rotor, I-4 is the radial permanent magnet, I-5 is the surface-mounted permanent magnet, I-6 is the armature tooth, I-7 is the fault-tolerant tooth, and I-8 is the modulation tooth.

[0027] 1 represents the rotor; 11 represents the rotor core; 12 represents the magnet.

[0028] 2 represents the stator; 21 represents the stator core; 22 represents the stator teeth; 221 represents the auxiliary teeth; and 222 represents the fault-tolerant teeth.

[0029] 31 and 32 are coils;

[0030] 4 represents annular magnetic leakage. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0032] In this invention, the terms "first," "second," etc. (if present) in the invention and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0033] To address the problem of large no-load back EMF and low short-circuit impedance in existing permanent magnet vernier motors, which makes it difficult to suppress inter-turn short-circuit current, one embodiment of the present invention provides a highly fault-tolerant, high torque-density multiphase permanent magnet vernier motor, such as... Figure 2 As shown, it includes: rotor 1, stator 2, and two sets of three-phase windings disposed on the stator.

[0034] See Figure 2 The rotor 1 includes a rotor core 11 and a magnet 12, and the rotor is a surface-mounted structure.

[0035] See Figure 2In this embodiment, the stator 2 is disposed on the outside of the rotor 1, and the stator 2 specifically includes: a stator core 21, and stator teeth 22 disposed circumferentially on the inner side of the stator core 21;

[0036] A slot is provided at the tip of the stator tooth 22, forming multiple auxiliary teeth 221 at the stator tooth tip; because the stator tooth tip has a slot, in this embodiment, the stator tooth 22 is a split tooth. This split tooth structure can effectively increase the number of harmonics in the motor operation, improve the no-load back EMF, and give the motor a high torque density; Figure 2 As shown, in this embodiment, the tips of the stator teeth are specifically C-shaped, and this split tooth shape can effectively improve the electromagnetic performance of the motor.

[0037] Continue reading Figure 2 In this embodiment, a slot is provided in the upper middle part of the stator tooth 22, so that two fault-tolerant teeth 222 are formed in the upper middle part of the stator tooth 22, and coils 31 and 32 are wound on the two fault-tolerant teeth 222 respectively.

[0038] The stator tooth 22 and the two coils 31 and 32 wound on it constitute a fault-tolerant unit. The two coils 31 and 32 in the same fault-tolerant unit are located in two sets of three-phase windings respectively. When working, the current amplitude and phase of the two windings 31 and 32 in the same fault-tolerant unit are the same.

[0039] In this embodiment, there are two sets of three-phase windings. A1, B1, and C1 represent the coils of phases A, B, and C in one set of three-phase windings, respectively, while A2, B2, and C2 represent the coils of phases A, B, and C in the other set of three-phase windings, respectively. Since the two coils in the same fault-tolerant unit are supplied with currents of the same amplitude and phase during operation, their magnetomotive forces cancel each other out during healthy motor operation, preventing ring-shaped leakage flux and resulting in low impedance in the circuit. However, when an inter-turn short-circuit fault occurs in the motor, the current in the short-circuited turn changes. This causes the magnetomotive forces of the coils wound on the two fault-tolerant teeth within the fault-tolerant unit containing the short-circuited coil to become unable to cancel each other out, resulting in... Figure 3 The annular leakage flux 4 shown is equivalent to adding a leakage inductance to the short-circuit loop. Due to the high permeability of the iron core, this leakage inductance is relatively large, effectively solving the problem of impedance and back EMF mismatch in the short-circuit loop, thus effectively suppressing the inter-turn short-circuit current. Therefore, the permanent magnet vernier motor provided in this embodiment, like a traditional vernier motor, has the advantage of high torque density during normal operation. After an inter-turn or even single-phase short-circuit fault occurs, the annular leakage flux on the split teeth achieves a transition from low to high short-circuit loop impedance, resulting in high torque density and strong fault tolerance.

[0040] In this embodiment, because the two sets of three-phase windings adopt a special phase-splitting method, when a single-phase short circuit occurs in one set of three-phase windings, based on the same principle, the fault-tolerant unit where the short-circuited phase coil is located will experience ring-shaped leakage flux 4 because the magnetomotive forces of the two coils cannot cancel each other out. Figure 4 As shown. Therefore, this embodiment also has a strong suppression effect on single-phase short-circuit current.

[0041] See Figure 2 In this embodiment, a slot is provided at the tip of the stator tooth 22, that is, at the end near the rotor, forming two auxiliary teeth 221; a slot is provided in the upper middle part of the stator tooth, that is, at the end near the rotor core, forming two fault-tolerant teeth 222; therefore, the entire stator tooth is "H" shaped.

[0042] Optionally, in this embodiment, the number of rotor pole pairs is P. r =10, the number of modulation blocks is P f =12, according to the magnetic field modulation theory, the number of stator pole pairs P a and rotor pole pair number P r P must be satisfied f =P a +P r Accordingly, in this embodiment, the number of stator pole pairs is P. a =2, the motor pole ratio is 5. In this embodiment, the number of modulation blocks is equal to the number of auxiliary teeth.

[0043] To further increase the number of available air gap magnetic permeability harmonics, this embodiment employs an unequal spacing auxiliary tooth arrangement. Specifically, in this embodiment, the spacing between auxiliary teeth within the same stator tooth is greater than the spacing between stator teeth in adjacent stator teeth. This allows the introduction of low-order air gap magnetic permeability harmonics that are not equal to the number of auxiliary teeth, thereby improving the no-load back EMF and torque.

[0044] It should be noted that, while ensuring the number of stator pole pairs P a Rotor pole pair number P r and the number of modulation blocks P f While satisfying the magnetic field modulation principle, different slotting schemes can be adopted for the stator tooth tips according to actual fault tolerance and torque density requirements. For example, in some optional embodiments, two slots can be formed at the tips of the stator teeth to create three auxiliary teeth, in which case the stator tooth tips are E-shaped. In some optional embodiments, more slots can also be provided at the tips of the stator teeth.

[0045] The permanent magnet vernier motor with "H"-shaped split teeth provided in this embodiment is compared with the existing permanent magnet vernier motor based on Y-shaped split teeth under the same short-circuit fault. Figure 5 As shown. According to Figure 5It can be seen that the permanent magnet vernier motor provided in this embodiment has a small change in the short-circuit current of its short-circuit branch when a short-circuit fault occurs, indicating that the motor can effectively suppress the short-circuit current and has strong fault tolerance performance.

[0046] In summary, this embodiment improves the structure, relative position, and winding phase design of the stator teeth, thereby increasing the no-load back EMF and enabling the circuit impedance to change from low to high after inter-turn or even single-phase short-circuit faults. This effectively solves the problem of mismatch between high back EMF and low impedance, and significantly improves the fault tolerance performance of the high torque density permanent magnet vernier motor.

[0047] It is easy to understand that if the rotor of a permanent magnet vernier motor is located outside the stator, then the stator teeth are located circumferentially outside the stator core.

[0048] Based on the above-mentioned high-torque-density multiphase permanent magnet vernier motor with strong fault tolerance, in another embodiment of the present invention, a new energy vehicle is provided, wherein the drive motor is the above-mentioned high-torque-density multiphase permanent magnet vernier motor with strong fault tolerance.

[0049] Because the drive motor has both high torque density and strong fault tolerance, the new energy vehicle provided in this embodiment has good stability and high reliability.

[0050] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A high-torque-density, fault-tolerant, multi-phase permanent magnet vernier motor, characterized in that, include: The rotor, the stator, and two sets of three-phase windings disposed on the stator; The stator includes: a stator core, and stator teeth arranged circumferentially on the stator core; one or more slots are provided at the tips of the stator teeth to form multiple auxiliary teeth at the tips of the stator teeth; a slot is provided in the upper middle part of the stator teeth to form two fault-tolerant teeth in the upper middle part of the stator teeth, and a coil is wound on the fault-tolerant teeth. The stator teeth and the two coils wound on them constitute a fault-tolerant unit. The two coils in the same fault-tolerant unit are located in two sets of three-phase windings respectively. When working, the current amplitude and phase of the two windings in the same fault-tolerant unit are the same. The rotor is disposed inside the stator, and the stator teeth are disposed inside the stator core; or, the rotor is disposed outside the stator, and the stator teeth are disposed outside the stator core.

2. The high-torque-density, fault-tolerant multiphase permanent magnet vernier motor as described in claim 1, characterized in that, There are unequal tooth pitches between all auxiliary teeth.

3. The high-torque-density, fault-tolerant multiphase permanent magnet vernier motor as described in claim 1 or 2, characterized in that, Number of modulation blocks P f Stator pole pair number P a and the number of rotor pole pairs P r Satisfy P a +P r =P f .

4. The high-torque-density, fault-tolerant multiphase permanent magnet vernier motor as described in claim 3, characterized in that, The stator employs a fractional-slot concentrated winding.

5. The high-torque-density, fault-tolerant multiphase permanent magnet vernier motor as described in claim 4, characterized in that, The tips of the stator teeth are C-shaped.

6. The high-torque-density, fault-tolerant multiphase permanent magnet vernier motor as described in claim 4, characterized in that, The tips of the stator teeth are E-shaped.

7. A new energy vehicle, characterized in that, Its drive motor is a high-torque-density multiphase permanent magnet vernier motor with strong fault tolerance as described in any one of claims 1 to 6.

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