Symmetrical winding method for winding inductors of bivalve permanent magnet motor

Abstract

The invention belongs to the field of aviation permanent magnet motor design, and particularly relates to a bivalve permanent magnet motor winding inductor symmetrical winding method. The method is suitable for the bivalve permanent magnet synchronous motor with a stator iron core as a whole and a stator armature divided into two sets of independent windings. According to the winding mode, electromagnetic coupling only exists at two specific stator slots between the two sets of windings, so that mutual inductance between the two sets of windings and inductance unbalance degree during operation of a single set of windings are reduced. By changing the winding mode of the stator armature winding, the mutual inductance between the two windings of the bivalve motor armature and the inductance unbalance degree of the single winding are reduced, the working stability of the single winding of the motor is enhanced, and the redundancy fault-tolerant capability of the motor is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of aviation permanent magnet motor design, and particularly relates to a double-lobe permanent magnet motor winding inductance symmetrical winding method. BACKGROUND

[0002] With the development of new electric aircraft technology, light weight, high efficiency and high reliability permanent magnet motor has become an important development direction of electric propulsion motor. Permanent magnet synchronous motor can provide part or all of the flight thrust for electric propulsion aircraft, which can effectively solve the noise and pollution emission problems brought by the traditional aircraft propulsion system. As the core component of electric propulsion of electric aircraft, the performance of permanent magnet synchronous motor determines the key performance of electric aircraft, such as climbing performance and flight efficiency. In the process of electric aircraft gradually developing towards large-scale, long-range and high reliability, high power-to-weight ratio, high efficiency and high reliability permanent magnet synchronous motor has become an essential technical feature of future electric aircraft electric propulsion motor.

[0003] For high-power permanent magnet synchronous motor, the design of stator split can make the stator modular production, easy to manufacture and maintain, and can also improve the redundancy fault tolerance of the motor. For the permanent magnet synchronous motor with the stator core as a whole and the stator armature as two sets of windings, in order to maximize the use of the core, there is no physical isolation between the two lobes, and there is inevitable electrical coupling between the two sets of windings. Due to the electrical coupling and the edge effect similar to linear motor, different winding methods of windings will cause unbalanced inductance of windings, which directly leads to unbalanced three-phase current and neutral potential offset of the controller, increasing the system common mode noise. In view of the unbalanced inductance of three-phase windings, the current improvement scheme usually has: rotor skew, sacrificing average torque; custom design of magnetic pole, shape optimization, high cost. The existing technology has a large cost to solve the problem of unbalanced inductance of stator armature winding split winding, and needs to develop a special winding design method. SUMMARY

[0004] In order to solve the above problems, the application provides a double-lobe permanent magnet motor winding inductance symmetrical winding method, which is suitable for a double-lobe permanent magnet synchronous motor with a stator core as a whole and a stator armature divided into two independent windings. The winding method makes the two sets of windings only have electromagnetic coupling at two specific stator slots, so as to reduce the mutual inductance between the two sets of windings and the inductance imbalance degree of single set of windings when running.

[0005] Among them, the first set of windings has 18 stator teeth numbered 1-18, and the second set of windings has 18 stator teeth numbered 19-36, and the winding method comprises:

[0006] A phase occupies 1(A), 2(a), 7(a), 8(A), 13(A), 14(a), 19(a), 20(A), 25(A), 26(a), 31(a), 32(A);

[0007] B phase occupies 3(b), 4(B), 9(B), 10(b), 15(b), 16(B), 21(B), 22(b), 27(b), 28(B), 33(B), 34(b);

[0008] C phase occupies 5(C), 6(c), 11(c), 12(C), 17(C), 18(c), 23(c), 24(C), 29(C), 30(c), 35(c), 36(C);

[0009] Wherein, the capital letter represents the positive winding of the coil, and the lowercase letter represents the reverse winding of the coil.

[0010] Preferably, the motor is a 36-slot 30-pole fractional-slot permanent magnet synchronous motor, and the stator winding is a concentrated winding structure.

[0011] Preferably, the two sets of windings only have electromagnetic coupling at the first slot and the 19th slot.

[0012] Preferably, through the winding mode, when one set of windings fails, the three-phase inductance imbalance of the normally operating single set of windings is less than 4.5%.

[0013] Preferably, the calculation formula of the three-phase inductance imbalance is:

[0014] ;

[0015] Wherein, , , are the total inductance of the A phase, the B phase and the C phase in the single set of windings, respectively.

[0016] Preferably, in step S5, through the winding mode, when one set of windings works alone, the comprehensive imbalance factor of the back electromotive force is less than 1.3%.

[0017] Preferably, the comprehensive imbalance factor is determined by the negative sequence component imbalance degree and the zero sequence component participation degree , and the calculation formula is:

[0018] ;

[0019] wherein:

[0020] ;

[0021] ;

[0022] wherein, , and are the positive, negative and zero sequence voltage components respectively after the three-phase back EMF is decomposed by symmetrical component method.

[0023] The application reduces the mutual inductance between the two sets of windings of the double-flap motor and the unbalance degree of the single set of windings, enhances the stability of the single set of windings when working, and thus improves the redundancy fault tolerance capability of the motor. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 is a schematic diagram of a modular cascaded motor system architecture.

[0025] Figure 2 is a schematic diagram of a traditional double-flap stator winding method.

[0026] Figure 3 is a traditional double-flap stator winding diagram.

[0027] Figure 4 is a schematic diagram of a double-flap stator winding method of a preferred embodiment of the double-flap permanent magnet motor winding symmetrical winding method of the application.

[0028] Figure 5 is a double-flap stator winding diagram of the embodiment shown in the application Figure 4 .

[0029] Figure 6 is a schematic diagram of a traditional double-flap motor back EMF.

[0030] Figure 7 is a schematic diagram of a double-flap motor back EMF of the application. DETAILED DESCRIPTION

[0031] For the purpose of making the technical solutions, purposes and advantages of the present application clearer, the technical solutions in the embodiments of the present application will be described in more detail below with reference to the drawings in the embodiments of the present application. In the drawings, the same or similar notations represent the same or similar elements or elements with the same or similar functions throughout. The described embodiments are part of the embodiments of the present application, rather than all the embodiments. The embodiments described below with reference to the drawings are exemplary and are intended to explain the present application, and cannot be understood as a limitation of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application. The embodiments of the present application will be described in detail below with reference to the drawings.

[0032] The present application provides a double-lobe permanent magnet motor winding inductance symmetrical winding method, which is suitable for a double-lobe permanent magnet synchronous motor with a whole stator core and a stator armature divided into two independent windings. The winding method makes the two sets of windings only have electromagnetic coupling at two specific stator slots, so as to reduce the mutual inductance between the two sets of windings and the inductance imbalance degree when a single set of windings operates.

[0033] Among them, the first set of windings has 18 stator teeth numbered 1-18, and the second set of windings has 18 stator teeth numbered 19-36. The winding method comprises:

[0034] A phase occupies 1 (A), 2 (a), 7 (a), 8 (A), 13 (A), 14 (a), 19 (a), 20 (A), 25 (A), 26 (a), 31 (a), 32 (A);

[0035] B phase occupies 3 (b), 4 (B), 9 (B), 10 (b), 15 (b), 16 (B), 21 (B), 22 (b), 27 (b), 28 (B), 33 (B), 34 (b);

[0036] C phase occupies 5 (C), 6 (c), 11 (c), 12 (C), 17 (C), 18 (c), 23 (c), 24 (C), 29 (C), 30 (c), 35 (c), 36 (C);

[0037] Among them, the capital letter represents the positive winding of the coil, and the lowercase letter represents the reverse winding of the coil.

[0038] The present application is applied to a modular cascaded motor system. The system is composed of two motors in cascade, and each motor is controlled by two control modules, such as Figure 1As shown, the stator armature winding of the motor is divided into two parts, forming a double-lobed motor. The double-lobed permanent magnet synchronous motor adopts a 36-slot, 30-pole fractional-slot structure, and the stator winding is a concentrated double-winding structure, which reduces the stator winding ends and lowers the stator weight; the stator winding uses high conductivity, high temperature resistant copper enameled wire.

[0039] According to the traditional stator winding method of a double-lobed motor, the two sets of windings have electromagnetic coupling relationships with multiple stator teeth. For example... Figure 2 and Figure 3 As shown. Figure 2 This is a schematic diagram of a traditional double-lobed stator winding method. Each block in the diagram represents a stator tooth, and there are a total of 36 stator teeth. Uppercase letters indicate forward winding of the coil, and lowercase letters indicate reverse winding of the coil. The first set of winding diagrams is labeled "Ⅰ", and the second set of winding diagrams is labeled "Ⅱ". Figure 3 This is a diagram of a traditional double-lobe stator winding. As can be seen from the diagram, in this winding method, there are 10 slots with electromagnetic coupling between the two sets of windings: 36 and 1, 1 and 2, 2 and 3, 3 and 4, 4 and 5, 18 and 19, 19 and 20, 20 and 21, 21 and 22, and 22 and 23.

[0040] This application describes a stator winding method for a dual-lobe motor, where the two sets of windings have electromagnetic coupling between only two stator teeth. In some optional embodiments, the motor is a 36-slot, 30-pole fractional-slot permanent magnet synchronous motor, and the stator winding has a concentrated winding structure. For example... Figure 4 and Figure 5 As shown. Figure 4 This is a schematic diagram of a traditional double-lobed stator winding method. Each block in the diagram represents a stator tooth, and there are a total of 36 stator teeth. Uppercase letters indicate forward winding of the coil, and lowercase letters indicate reverse winding of the coil. The first set of winding diagrams is labeled "Ⅲ", and the second set of winding diagrams is labeled "Ⅳ". Figure 5 This is a diagram of a traditional double-lobed stator winding.

[0041] In some alternative embodiments, electromagnetic coupling exists between the two windings only at slots 1 and 19. Figure 4 and Figure 5 As can be seen, in the winding method described in this application, only two slots (1 and 19) have electromagnetic coupling between the two sets of windings. Therefore, this winding method can reduce the coupling between the two sets of windings in a dual-lobe motor, thereby increasing the independence of each set of windings and improving their respective inductance balance. This provides a more accurate basis for the research of dual-lobe motors.

[0042] In some alternative implementations, the winding method ensures that when one set of windings fails, the three-phase inductance imbalance of a normally functioning single set of windings is less than 4.5%.

[0043] In some alternative implementations, the formula for calculating the three-phase inductance imbalance is:

[0044] ;

[0045] in, , , These are the total inductances of phases A, B, and C in a single winding, respectively.

[0046] Finite element simulation models were established for both winding methods, and the winding inductances were obtained respectively, as shown in Tables 1 and 2. Table 1 shows that in the traditional winding method, the six-phase windings have the same self-inductance, and many windings are inductively interconnected between the two sets of windings; only the mutual inductance between A / C is negligible. Table 2 shows that the six-phase windings have the same self-inductance, and the inductive interconnection between many windings is negligible; only the mutual inductance between A / C is not negligible.

[0047] Table 1. Winding Inductance of Traditional Wire Winding Method

[0048]

[0049] Table 2. Winding inductance of the present invention using the winding method

[0050]

[0051] When the motor is running normally, the total inductance of the six-phase windings is balanced. However, if one set of windings fails and cannot operate, the three-phase inductance of that single set of windings will become unbalanced. (Take:)

[0052] ;

[0053] Where La is the total inductance of a single-phase winding, Ls is the self-inductance of a single-phase winding, and Lm is the mutual inductance of the windings. The inductance of a single winding for the two winding methods is shown in Table 3.

[0054] Table 3 Single-winding inductance

[0055]

[0056] The three-phase inductor imbalance is defined as follows:

[0057] .

[0058] The unbalance of the three-phase inductors obtained by the conventional winding method and the winding method of the present invention are 6.8% and 4.4%, respectively. The unbalance is reduced by (6.8%-4.4%) / 6.8%=35.3%, and the improvement is quite significant.

[0059] In some alternative implementations, in step S5, by means of the winding method, when a set of windings operates alone, the overall imbalance factor of its back EMF is less than 1.3%.

[0060] In some alternative implementations, the imbalance factor is integrated. The unbalance of the negative sequence component of the back electromotive force and zero-order component participation The decision is made using the following formula:

[0061] ;

[0062] in:

[0063] ;

[0064] ;

[0065] in, , and These are the positive-sequence, negative-sequence, and zero-sequence voltage components obtained after decomposing the back EMF of the three-phase windings using the symmetrical component method.

[0066] Finite element simulation models were established for both winding methods. When only a single winding of the motor was in operation, the back EMFs of the three-phase windings of the motors with the two winding methods were obtained, as shown in the figure. Figure 6 , Figure 7 The symmetric component method is used to decompose it into an ascending order. Negative order Zero sequence Quantity.

[0067] ;

[0068] in For rotation operators, =e -j120° .

[0069] Define the back potential imbalance Zero-order participation Comprehensive factors They are respectively:

[0070]

[0071] The calculation results are shown in Table 4. As can be seen from the table, the back EMF imbalance of the winding method in this application... It decreased by (1.6% - 1.27%) / 1.6% = 20.6%, based on the comprehensive factor. It decreased by (1.63%-1.28%) / 1.63%=21.5%.

[0072] Table 4 Back Potential Imbalance

[0073]

[0074] In summary, this application can achieve the following effects by changing the stator armature winding method while keeping the rotor unchanged.

[0075] 1. Reducing the mutual inductance between the two windings of the armature in a dual-lobe motor decreases the electromagnetic coupling between them, thereby mitigating the impact on the other winding in the event of a fault in one winding and improving the motor's redundancy and fault tolerance. In the embodiment, the inductance imbalance decreased by 35.3%.

[0076] 2. Reducing the inductance imbalance of a single winding in the armature of a dual-lobe motor reduces three-phase electrical imbalance and controller neutral potential shift, lowers system common-mode noise, and improves motor redundancy and fault tolerance. In the embodiment, the back EMF imbalance of a single winding is reduced by 20.6%.

[0077] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for symmetrically winding the inductance of a double-lobed permanent magnet motor winding, characterized in that, This invention is applicable to a double-lobed permanent magnet synchronous motor in which the stator core is a single unit and the stator armature is divided into two independent windings. The winding method ensures that there is only electromagnetic coupling between the two windings at two specific stator slots, thereby reducing the mutual inductance between the two windings and the inductance imbalance when a single winding is in operation. The first set of windings has 18 stator teeth numbered 1-18, and the second set of windings has 18 stator teeth numbered 19-36. The winding method includes: Phase A occupies 1 (A), 2 (a), 7 (a), 8 (A), 13 (A), 14 (a), 19 (a), 20 (A), 25(A), 26 (a), 31 (a), 32 (A); Phase B occupies 3 (b), 4 (B), 9 (B), 10 (b), 15 (b), 16 (B), 21 (B), 22 (b), 27 (b), 28 (B), 33 (B), 34 (b); Phase C occupies 5 (C), 6 (C), 11 (C), 12 (C), 17 (C), 18 (C), 23 (C), 24 (C), 29 (C), 30 (C), 35 (C), 36 (C); In this context, uppercase letters indicate that the coil is wound in the forward direction, while lowercase letters indicate that the coil is wound in the reverse direction.

2. The method for symmetrically winding the inductance of a double-lobed permanent magnet motor according to claim 1, characterized in that, The motor is a 36-slot, 30-pole fractional-slot permanent magnet synchronous motor with a concentrated stator winding structure.

3. The method for symmetrically winding the inductance of a double-lobed permanent magnet motor according to claim 2, characterized in that, Electromagnetic coupling exists between the two sets of windings only at slots 1 and 19.

4. The method for symmetrically winding the inductance of a double-lobed permanent magnet motor according to claim 1, characterized in that, With the aforementioned winding method, when one set of windings fails, the three-phase inductance imbalance of a normally operating single set of windings is less than 4.5%.

5. The method for symmetrically winding the inductance of a double-lobed permanent magnet motor according to claim 4, characterized in that, The formula for calculating the three-phase inductor imbalance is as follows: ； in, , , These are the total inductances of phases A, B, and C in a single winding, respectively.

6. The method for symmetrically winding the inductance of a double-lobed permanent magnet motor according to claim 1, characterized in that, In step S5, through the winding method, when a set of windings works alone, the overall imbalance factor of its back EMF is less than 1.3%.

7. The method for symmetrically winding the inductance of a double-lobed permanent magnet motor according to claim 6, characterized in that, Comprehensive Imbalance Factors The unbalance of the negative sequence component of the back electromotive force and zero-order component participation The decision is made using the following formula: ； in: ； ； in, , and These are the positive-sequence, negative-sequence, and zero-sequence voltage components obtained after decomposing the back EMF of the three-phase windings using the symmetrical component method.

Images