A toroidal winding permanent magnet fault-tolerant motor and design method thereof

Abstract

The present invention discloses a toroidal winding permanent magnet fault-tolerant motor and a design method thereof, which belongs to the field of fault-tolerant motors, including: in the motor winding topology, each phase winding corresponds to positive and negative phase bands; if the number of winding phases is an even number greater than or equal to 6, it is a large and small phase band topology structure or an asymmetric topology structure with a positive and negative phase band number of coils; otherwise, the winding topology structure is a large and small phase band topology structure; in the large and small phase band topology structure, the positive and negative phase band angles corresponding to each phase winding are not equal; in the asymmetric topology structure with a positive and negative phase band number of coils, the positive and negative phase band angles corresponding to each phase winding are equal but the number of coil groups is not equal; the design method includes: determining the winding topology structure and the pole slot matching parameters according to the number of winding phases and index parameters, and determining the corresponding size parameters, and filtering out the scheme with the best comprehensive performance after analyzing and calculating the electromagnetic performance and fault-tolerant performance of each scheme. The present invention can make the toroidal winding motor have strong fault-tolerant performance and good electromagnetic performance at the same time.

Description

Technical Field

[0001] The present invention belongs to the field of fault-tolerant motors, and more specifically, relates to a toroidal winding permanent magnet fault-tolerant motor and a design method thereof. Background Art

[0002] The transportation industry has stricter restrictions on carbon emissions, and comprehensive electrification has become an inevitable trend. As the core driving component of a vehicle, the motor has strict requirements for high power density and high reliability. Permanent magnet motors have become the preferred type of drive motors in the aerospace, electric vehicle, and shipbuilding fields due to their high power density, high efficiency, easy control, and easy maintenance. However, the difficult-to-adjust excitation magnetic field of permanent magnet motors has also caused concern and worry about their reliability.

[0003] Among the various faults that may occur in permanent magnet motors, turn-to-turn and single-phase short circuits are the most likely types of faults. The windings in the slots will fail due to local overheating, mechanical stress, power overload, etc., which will lead to insulation failure and turn-to-turn short circuit faults. A sudden short circuit will form a loop with low impedance between the short-circuited turns. However, the rotor will continue to rotate due to inertia after the fault. The back electromotive force induced by the short-circuited turns will cause the current in the short-circuit loop to soar, causing local overheating and further damage to the insulation. Positive feedback causes the fault to continue to expand, which not only reduces the electromagnetic performance of the motor, but also seriously threatens the safety of the system. Therefore, effectively suppressing the short-circuit current under single-phase short circuit and turn-to-turn short circuit faults in permanent magnet motors has become an urgent problem to be solved.

[0004] High impedance design is a common method for permanent magnet fault-tolerant motors to effectively suppress short-circuit current. Fractional slot concentrated windings have become the mainstream topology of permanent magnet fault-tolerant motors because of their advantages such as strong electromagnetic isolation, large inductance, and low tooth torque. The structural design with isolation teeth also further improves the electromagnetic and temperature isolation between the windings. Filling the slots with magnetic wedges or designing them as closed slots can also increase the winding leakage inductance. However, for common turn-to-turn short circuits and single-phase short circuit faults, due to the small impedance of the short-circuit loop, the short-circuit current can reach dozens of times the rated current or even higher. High impedance design can only alleviate the danger of the fault to a certain extent, but cannot fundamentally solve the problem of large short-circuit current. Moreover, high impedance design will also reduce the power density of the motor. For example, in the patent document with application publication number CN109510558A, a six-phase permanent magnet fault-tolerant motor and its drive system are provided, such as Figure 1 As shown, it uses concentrated windings to improve isolation capability, and uses two sets of three-phase full-bridge drive circuits to control the armature windings respectively; Figure 1In the figure, I-1 represents the stator, I-2 represents the rotor, and I-3 represents the permanent magnet. When a fault occurs in the system, the corresponding bidirectional thyristor is turned on to form a half-bridge power circuit with a neutral point, thereby realizing the control of the system's fault-tolerant operation. The entire system has the advantages of magnetic isolation, physical isolation, thermal isolation, and small cogging torque. However, after a short-circuit fault occurs in the above six-phase permanent magnet fault-tolerant motor and its drive system, due to the small short-circuit loop impedance, the short-circuit current will reach dozens of times the rated current, which makes the motor less reliable. Therefore, how to make the impedance of the permanent magnet motor change from low to high after a short-circuit fault occurs becomes the key to improving its fault-tolerant performance.

[0005] An ideal permanent magnet fault-tolerant motor should have the characteristics of low impedance during normal operation and ultra-high impedance during short-circuit faults. The toroidal winding has just such characteristics because of its winding yoke characteristics. After a turn-to-turn or single-phase short-circuit fault occurs, the toroidal winding permanent magnet motor will excite the yoke leakage magnetic field at the yoke. This larger yoke leakage inductance can effectively suppress the short-circuit current. At present, the toroidal winding topology is mainly divided into two types: 2π / m phase belt and π / m phase belt, where m represents the number of winding phases. The toroidal winding motor using the π / m phase belt topology does not have single-phase short-circuit fault tolerance performance. The toroidal winding motor using the 2π / m phase belt topology has better fault tolerance performance, but its phase belt harmonics are large and the distribution coefficient is low, which is difficult to be used in high-speed and high-frequency occasions. For example, in the patent document with application publication number CN106230213A, a multi-phase synchronous generator with automatic fault tolerance for stator turn-to-turn short-circuit faults is provided, such as Figure 2 As shown, it adopts a 2π / m phase toroidal winding topology (m represents the number of winding phases). Figure 2 In the figure, II-1 represents the stator core, II-2 represents the stator ring winding, II-3 represents the permanent magnet, II-4 represents the rotor core, and II-5 represents the shaft. After a short-circuit fault occurs in the motor, yoke leakage magnetic flux will appear, and the leakage inductance of the motor will increase. The short-circuit current suppression effect is very good, and the normal output capacity of the generator can be approximately maintained. However, the phase-band harmonics are large. In high-speed applications, the permanent magnet loss is large and the electromagnetic performance is poor.

[0006] In general, existing toroidal winding motors cannot have both excellent electromagnetic performance and fault tolerance performance. Summary of the invention

[0007] In view of the defects and improvement needs of the prior art, the present invention provides a toroidal winding permanent magnet fault-tolerant motor and a design method thereof, the purpose of which is to enable the toroidal winding motor to have both strong fault-tolerant performance and good electromagnetic performance.

[0008] To achieve the above object, according to one aspect of the present invention, a toroidal winding permanent magnet fault-tolerant motor is provided, in which in the winding topology structure, each phase winding corresponds to two positive and negative phase bands;

[0009] If the number of winding phases m is an even number greater than or equal to 6, the winding topology is a large-small phase belt topology or an asymmetric topology with a positive and negative phase belt number of coils; otherwise, the winding topology is a large-small phase belt topology;

[0010] In the large and small phase belt topology, the positive and negative phase belt angles corresponding to each phase winding are not equal;

[0011] In the topological structure with asymmetric number of coils under the positive and negative phase bands, the angles of the positive and negative phase bands corresponding to each phase winding are equal, but the number of coil groups under the positive and negative phase bands corresponding to each phase winding are not equal.

[0012] Furthermore, in the topological structure with asymmetric number of coils under positive and negative phases, the number of pole pairs p is an odd number, so as to facilitate physical isolation between each set of windings.

[0013] Furthermore, in the topological structure with asymmetric number of coils under the positive and negative phase bands, the number of coils of each phase winding under the corresponding positive and negative phase bands differs by 1.

[0014] Furthermore, when the motor is an integer-slot motor, in the large- and small-phase belt topology, the number of slots per pole per phase is q≥2.

[0015] According to another aspect of the present invention, a design method for the above-mentioned toroidal winding permanent magnet fault-tolerant motor provided by the present invention is provided, the motor is an integer slot motor, and the design method comprises the following steps:

[0016] (S1) Under the condition of satisfying preset conditions, determining the topological structure of the toroidal winding permanent magnet fault-tolerant motor and one or more sets of pole-slot matching parameters according to the winding phase number m and the index parameter, and taking each set of pole-slot matching parameters and the corresponding topological structure as a candidate motor structure;

[0017] The preset conditions include: the number of motor slots Z = kmp and the number of pole pairs k is a positive integer, f max It represents the highest frequency after considering the switching frequency of the controller and the heat dissipation capacity of the motor itself, and n represents the speed;

[0018] (S2) determining the size parameters of each candidate motor structure; the size parameters include: stator inner diameter, armature length, air gap length, rotor outer diameter and yoke thickness;

[0019] (S3) Analytically calculating the electromagnetic performance and fault tolerance performance of each candidate motor structure in combination with the size parameters, and selecting the optimal candidate motor structure based on the electromagnetic performance and fault tolerance performance, and outputting its topological structure, pole-slot matching parameters and size parameters.

[0020] Furthermore, the preset condition also includes: the number of motor slots Z is an even number to avoid the generation of a large unilateral magnetic pull.

[0021] Further, after step (S3), the method further includes:

[0022] (S4) According to the topological structure, pole-slot matching parameters and size parameters determined in step (S3), a finite element model of the toroidal winding permanent magnet fault-tolerant motor is established to calculate the performance parameters of the toroidal winding permanent magnet fault-tolerant motor, and according to the preset index parameters, it is judged whether all performance parameters meet the index requirements. If so, the design is completed; otherwise, it goes to step (S1).

[0023] Further, in step (S3), the fault tolerance is achieved by short-circuit current i f Measure, short-circuit current i f The calculation formula is:

[0024]

[0025]

[0026]

[0027]

[0028]

[0029]

[0030]

[0031] Among them, λ represents the fault ratio, t0 represents the time when the short circuit occurs, L yoke is the yoke leakage inductance, L co1 represents the self-inductance of a single coil, ω represents the electrical angular velocity, u() represents the step function, represents the amplitude of permanent magnet flux, k q represents the distribution coefficient, θ1 represents the phase difference between the reverse potential and the reverse potential of the short-circuited coil, M col2 It represents the mutual inductance between the short-circuited coil and the remaining coils of the phase, M ph Represents the mutual inductance between phases, I q represents the q-axis current, I d represents the d-axis current, R c The resistance of each coil, R f Indicates the short-circuit contact resistance.

[0032] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects:

[0033] (1) The annular winding permanent magnet fault-tolerant motor provided by the present invention may have two topologies according to the number of phases of its winding: one is a large and small phase belt topology, in which the angles of the positive and negative phase belts in each phase winding are not equal; the other is an asymmetric coil number topology under the positive and negative phase belts, in which the angles of the positive and negative phase belts in each phase winding are the same but the number of coils is different; under these two topologies, through a special pole-slot matching design, the number of coils under the positive and negative phase belts in each phase winding is unequal, and in the event of a single-phase short circuit, the motor will be disconnected. When a fault occurs, in the same phase winding, the ampere-turns of the windings under the positive and negative phase belts are not equal, and the integral of the magnetic field strength on the yoke path is not 0, which will produce yoke leakage magnetic flux. The yoke leakage magnetic flux will add a yoke leakage inductance to the motor short-circuit loop, effectively suppressing the short-circuit current. Therefore, the annular winding permanent magnet motor provided by the present invention has good fault-tolerant performance; and, because the phase belt harmonics are small and the distribution coefficient is high under these two topological structures, the annular winding permanent magnet fault-tolerant motor provided by the present invention also has good electromagnetic performance.

[0034] (2) The design method of the annular winding permanent magnet fault-tolerant motor provided by the present invention starts from the fault tolerance perspective, firstly screens out the winding topology structure and pole-slot combination with fault-tolerant performance, then uses the analytical method to quickly evaluate the electromagnetic and fault-tolerant performance, and finally selects the best solution with the best comprehensive fault-tolerant performance and electromagnetic performance, thereby ensuring that the designed annular winding permanent magnet fault-tolerant motor has good fault-tolerant performance and electromagnetic performance at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic diagram of an existing six-phase permanent magnet fault-tolerant motor and its drive system;

[0036] Figure 2 A schematic diagram of an existing multi-phase synchronous generator with automatic fault tolerance for stator turn-to-turn short circuit fault;

[0037] Figure 3 Schematic diagram of the existing three-phase toroidal winding topology; wherein (a) is a 2π / m phase belt topology, and (b) is a π / m phase belt topology;

[0038] Figure 4 A schematic diagram of the topology of large and small phase bands provided in an embodiment of the present invention;

[0039] Figure 5 A schematic diagram comparing single-phase short-circuit currents of the large-small phase belt topology and the π / m phase belt topology provided by the embodiment of the present invention;

[0040] Figure 6 A schematic diagram of asymmetric topology of coil numbers under positive and negative phase bands provided by an embodiment of the present invention;

[0041] Figure 7A flow chart of a design method for an integer-slot annular winding permanent magnet fault-tolerant motor provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0043] In the present invention, the terms "first", "second", etc. (if any) in the present invention and the drawings are used to distinguish similar objects but not necessarily to describe a specific order or sequence.

[0044] Before explaining the technical solution of the present invention in detail, the fault tolerance principle of the toroidal winding permanent magnet fault-tolerant motor is briefly analyzed as follows:

[0045] When the motor is working normally, taking the three-phase winding motor as an example, since all the annular coils have the same winding direction and the sum of the three-phase currents is 0, according to Ampere's loop law, there are:

[0046] ∮Hdl=Ni a +Ni b +Ni c =N(i a +i b +i c )=0

[0047] Where N represents the number of series turns per phase, i a 、i b 、i c They represent the three-phase currents A, B and C respectively, H represents the magnetic field strength, and l represents the length of the yoke path.

[0048] According to the classical AC winding theory, the toroidal winding topology is often divided into Figure 3 The 2π / m phase band shown in (a) and Figure 3π / m phase belt shown in (b) in the figure. When a single-phase short circuit fault occurs, for the 2π / m phase belt topology, the sum of the m-phase currents is not 0, which will cause the appearance of yoke leakage magnetic flux, and a yoke leakage inductance will be added to the motor short-circuit loop. Since the yoke magnetic resistance is very small, this yoke leakage inductance will be much higher than the synchronous inductance, and the short-circuit current can be well suppressed. However, when the number of phases is small, the phase belt harmonics of the 2π / m phase belt topology is very large, which will cause a surge in permanent magnet losses, reduce the efficiency of the motor and increase the risk of demagnetization of the permanent magnet. In contrast, in the π / m phase belt topology, each phase corresponds to two phase belts, namely the positive and negative phase belts. The current phases of the windings under the positive and negative phase belts differ by 180° electrical angle, and the angles of the positive and negative phase belts corresponding to each phase winding are the same, the distribution coefficient is high and the phase belt harmonics are small. Therefore, the electromagnetic performance of the π / m phase belt topology is better, the power density of the motor output is larger, and the π / m phase belt topology is also the mainstream winding topology. However, when a single-phase short circuit fault occurs in the π / m phase belt ring winding topology, the ampere-turns of the windings in the two phase belts of the same corresponding phase are opposite to each other, the integral of the magnetic field intensity on the ring yoke path is 0, and no ring yoke leakage magnetic flux is generated. Therefore, without a special winding topology design, the conventional π / m phase belt topology does not have single-phase short circuit fault tolerance performance.

[0049] In order to solve the problem that the existing toroidal winding motor topology structure cannot have good fault tolerance and electromagnetic performance at the same time, the present invention provides a toroidal winding permanent magnet fault-tolerant motor and a design method thereof, the overall idea of ​​which is: to specially design the winding topology structure of the toroidal winding motor so that the number of coils located under the positive and negative phase bands in each phase winding are not equal, so as to ensure that the sum of the ampere-turns on the yoke path after short circuit is not 0, so that the toroidal winding motor has better fault tolerance while having better electromagnetic performance.

[0050] The following are examples.

[0051] Embodiment 1:

[0052] A toroidal winding permanent magnet fault-tolerant motor, such as Figure 4 As shown, its winding topology is a large and small phase belt topology, each phase winding corresponds to positive and negative phase belts, wherein the positive and negative phase belt angles corresponding to each phase winding are not equal, but the sum of the positive and negative phase belt angles corresponding to the same phase winding is 2π / m; in order to ensure that the winding can be divided into asymmetric positive and negative phase belts, for integer slot windings, the number of phase slots per pole per slot must be ensured to be q≥2 when the pole-slot combination is selected. The annular winding permanent magnet fault-tolerant motor provided in this embodiment is a 48-slot 8-pole motor, the number of phases is 3, and the number of slots per pole per phase is q=2; the positive phase belt angle corresponding to each phase winding is 90 degrees, and the negative phase belt angle is 30 degrees.

[0053] In this embodiment, since the positive and negative phase belt angles corresponding to the same phase winding are different, the number of coils located under the positive and negative phase belts in the same phase winding are not equal. Therefore, after a single-phase short circuit fault occurs, the ampere-turns on the yoke path are not equal, and the integral of the magnetic field strength on the yoke path is 0, which will cause the occurrence of yoke leakage magnetic flux, thereby effectively suppressing the short-circuit current.

[0054] The toroidal winding permanent magnet fault-tolerant motor provided by this embodiment is Figure 3 The single-phase short-circuit current comparison diagram of the π / m-phase belt topology shown in (b) is as follows Figure 5 As shown, from Figure 5 It can be seen that the asymmetric large and small phase belt ring winding topology has greatly improved the single-phase short-circuit fault tolerance performance compared with the traditional π / m phase belt topology, and its electromagnetic performance is also better than the 2π / m phase belt topology.

[0055] Embodiment 2:

[0056] A toroidal winding permanent magnet fault-tolerant motor, such as Figure 6 As shown, the number of winding phases is m=6, and the winding topology is an asymmetric topology structure with a positive and negative phase band number of coils. Each phase winding corresponds to a positive and a negative phase band, wherein the positive and negative phase band angles corresponding to each phase winding are equal, but the number of coil groups under the positive and negative phase bands corresponding to each phase winding are not equal; in this embodiment, the sum of the positive and negative phase band angles of each phase is 120 degrees.

[0057] In this embodiment, since the number of coil groups of the positive and negative phase bands corresponding to the same phase winding is not equal, the number of coils located under the positive and negative phase bands in the same phase winding is not equal; in this embodiment, the motor can also be regarded as a dual three-phase motor. In order to facilitate the physical isolation between each set of windings and reduce the coupling between the two sets of three-phase windings, as a preferred implementation, in this embodiment, the number of pole pairs p is an odd number, and as Figure 6 As shown, the number of coil groups of the same phase winding under the positive and negative phase bands differs by 1; when a single-phase short circuit fault occurs, the ampere-turns of the yoke path cannot be completely offset and yoke leakage magnetic flux is generated, which has the ability to suppress single-phase short circuit current. It should be noted that the pole pair number p and the difference between the number of coil groups of the same phase winding under the positive and negative phase bands are only a preferred implementation method and should not be understood as the only limitation of the present invention; in some other embodiments of the present invention, as long as the number of coil groups under the positive and negative phase bands corresponding to each phase winding is not equal, the pole pair number p can also be set to an even number.

[0058] When the number of winding phases is an even number greater than or equal to 6, a topological structure with an asymmetric number of coils under positive and negative phase belts can be adopted; in addition, the large and small phase belt topological structure provided in the above embodiment 1 can also be adopted.

[0059] Embodiment 3:

[0060] As the design method of the toroidal winding permanent magnet fault-tolerant motor provided in the above-mentioned embodiment 1 or embodiment 2, in this embodiment, the motor is specifically an integer slot motor, such as Figure 7 As shown, the design method provided in this embodiment includes the following steps:

[0061] (S0) Determine the index parameters; the index parameters include: rated power P N , Rated torque T N , number of phases m, speed n, etc.;

[0062] (S1) Under the condition of satisfying preset conditions, determining the topological structure of the toroidal winding permanent magnet fault-tolerant motor and one or more sets of pole-slot matching parameters according to the winding phase number m and the index parameter, and taking each set of pole-slot matching parameters and the corresponding topological structure as a candidate motor structure;

[0063] On the premise that the number of slots per pole and per phase is an integer, the number of slots should be an integer multiple of the product of the number of pole pairs and the number of phases. At the same time, in order to avoid the generation of a large unilateral magnetic pull, the number of slots should be an even number; in addition, the increase in the number of motor poles will reduce the weight and short-circuit current, and the high-frequency loss of the motor needs to be considered. Therefore, the number of motor poles needs to be reasonably selected according to the rotational speed and the maximum frequency; based on the above considerations, in this embodiment, the preset conditions include:

[0064] The number of motor slots Z = kmp and the number of motor slots Z is an even number; k is a positive integer,

[0065] Pole pairs f max It represents the highest frequency after considering the switching frequency of the controller and the heat dissipation capacity of the motor itself, and n represents the speed;

[0066] If the number of phases m is an even number greater than or equal to 6, then the asymmetric topology structure with the number of coils under the positive and negative phase belts or the large and small phase belt topology structure can be selected; in other cases, the large and small phase belt topology structure is selected;

[0067] (S2) determining the size parameters of each candidate motor structure; the size parameters include: stator inner diameter, armature length, air gap length, rotor outer diameter and yoke thickness;

[0068] Optionally, the stator inner diameter and the armature length can be determined according to the motor constant equation; the air gap length can be determined according to the actual application situation and empirical knowledge; after determining the air gap length, the rotor outer diameter and the yoke thickness can be further determined;

[0069] (S3) analyzing and calculating the electromagnetic performance and fault tolerance performance of each candidate motor structure in combination with the size parameters, and selecting the optimal candidate motor structure based on the electromagnetic performance and the fault tolerance performance, and outputting its topological structure, pole-slot matching parameters and size parameters;

[0070] Electromagnetic performance can be measured by torque, distribution coefficient, and harmonic content;

[0071] Fault tolerance performance through short-circuit current i f Measure, short-circuit current i f The smaller the short-circuit current i f The calculation formula is:

[0072]

[0073]

[0074]

[0075]

[0076]

[0077]

[0078]

[0079] Where λ represents the fault ratio (i.e., the number of short-circuit turns divided by the number of turns of each coil), t0 represents the time when the short circuit occurs, and L yoke is the yoke leakage inductance, L co1 represents the self-inductance of a single coil, ω represents the electrical angular velocity, u() represents the step function, represents the amplitude of permanent magnet flux, k q represents the distribution coefficient, θ1 represents the phase difference between the reverse potential and the reverse potential of the short-circuited coil, M col2 It represents the mutual inductance between the short-circuited coil and the remaining coils of the phase, M ph Represents the mutual inductance between phases, I q represents the q-axis current, I d represents the d-axis current, R c The resistance of each coil, R f Represents the short-circuit contact resistance; the above short-circuit current calculation formula fully considers the influence of the ring yoke leakage inductance on the short-circuit current when a single-phase short-circuit fault occurs, effectively improving the accuracy of the short-circuit current calculation and achieving an accurate measurement of the motor's fault tolerance performance;

[0080] After obtaining the electromagnetic performance and fault tolerance performance through analytical calculation, different weights can be given to the electromagnetic performance and fault tolerance performance according to the actual application scenario to comprehensively evaluate the overall performance of the motor;

[0081] In order to further ensure the reliability of the designed motor, this embodiment further includes, after step (S3):

[0082] (S4) establishing a finite element model of the toroidal winding permanent magnet fault-tolerant motor according to the topological structure, pole slot matching parameters and size parameters determined in step (S3) to calculate the performance parameters of the toroidal winding permanent magnet fault-tolerant motor, and judging whether all performance parameters meet the index requirements according to the preset index parameters, if so, the design is completed; otherwise, proceeding to step (S1);

[0083] It is easy to understand that, each time in step ( S1 ), the candidate motor structures determined are not exactly the same.

[0084] In general, the toroidal winding permanent magnet motor design method proposed in this embodiment effectively takes into account the high reliability and high power density of the motor body. The electromagnetic and fault tolerance performance of the scheme can be quickly evaluated by analytical methods. The proposed asymmetric winding topology design allows the motor to have single-phase short-circuit fault tolerance while not significantly reducing the electromagnetic performance, which is suitable for electric vehicles and aerospace fields that have extremely high requirements for motor power density and reliability.

[0085] It will be easily understood by those skilled in the art that the above description is only 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 in the protection scope of the present invention.

Claims

1. A toroidal winding permanent magnet fault-tolerant motor, characterized in that: In its winding topology structure, each phase winding corresponds to two positive and negative phase bands; if the number of winding phases m is an even number greater than or equal to 6, the winding topology structure is a large and small phase band topology structure or an asymmetric topology structure of the number of coils under the positive and negative phase bands; otherwise, the winding topology structure is a large and small phase band topology structure; In the large and small phase belt topology structure, the positive and negative phase belt angles corresponding to each phase winding are not equal; In the asymmetric topological structure of the number of coils under the positive and negative phase bands, the angles of the positive and negative phase bands corresponding to each phase winding are equal, but the number of coil groups under the positive and negative phase bands corresponding to each phase winding are not equal; When the motor is an integer slot motor, the design method of the toroidal winding permanent magnet fault-tolerant motor includes: (S1) Under the condition of satisfying preset conditions, determining the topological structure of the annular winding permanent magnet fault-tolerant motor and one or more sets of pole-slot matching parameters according to the winding phase number m and the index parameter, and taking each set of pole-slot matching parameters and the corresponding topological structure as a candidate motor structure; The preset conditions include: the number of motor slots Z=kmp and the number of pole pairs ; k is a positive integer, It represents the highest frequency after considering the switching frequency of the controller and the heat dissipation capacity of the motor itself. n Indicates the rotation speed; (S2) determining the size parameters of each candidate motor structure; the size parameters include: stator inner diameter, armature length, air gap length, rotor outer diameter and yoke thickness; (S3) Analytically calculating the electromagnetic performance and fault tolerance performance of each candidate motor structure in combination with the size parameters, and selecting the optimal candidate motor structure based on the electromagnetic performance and fault tolerance performance, and outputting its topological structure, pole-slot matching parameters and size parameters; (S4) According to the topological structure, pole-slot matching parameters and size parameters determined in step (S3), a finite element model of the toroidal winding permanent magnet fault-tolerant motor is established to calculate the performance parameters of the toroidal winding permanent magnet fault-tolerant motor, and according to the preset index parameters, it is judged whether all the performance parameters meet the index requirements. If so, the design is completed; otherwise, it goes to step (S1).

2. The toroidal winding permanent magnet fault-tolerant motor according to claim 1, characterized in that: In the asymmetric topological structure with the number of coils under the positive and negative phase bands, the number of pole pairs p is an odd number.

3. The toroidal winding permanent magnet fault-tolerant motor according to claim 2, characterized in that: In the asymmetric topological structure with the number of coils under the positive and negative phase bands, the number of coil groups of each phase winding under the corresponding positive and negative phase bands differs by 1.

4. The toroidal winding permanent magnet fault-tolerant motor according to claim 1, characterized in that: When the motor is an integer slot motor, in the large and small phase belt topology structure, the number of slots per pole and per phase is q≥2.

5. The toroidal winding permanent magnet fault-tolerant motor according to any one of claims 1 to 4, characterized in that: The preset condition also includes: the number of motor slots Z is an even number.

6. The toroidal winding permanent magnet fault-tolerant motor according to any one of claims 1 to 4, characterized in that: In the step (S3), the fault tolerance is achieved by short-circuit current Measure, short circuit current The calculation formula is: in, represents the failure ratio, t 0 indicates the moment when the short circuit occurs, L yoke is the yoke leakage inductance, L co1 represents the self-inductance of a single coil, represents the electrical angular velocity, u () represents a step function, represents the amplitude of permanent magnet flux linkage, k q represents the distribution coefficient, Indicates the phase difference between the opposite potential and the back potential of the short-circuited coil. M col2 It represents the mutual inductance between the short-circuited coil and the remaining coils of the phase. M ph Represents the mutual inductance between phases, I q represents the q-axis current, I d represents the d-axis current, R c represents the resistance of each coil, R f Indicates the short-circuit contact resistance.

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