Double-layer winding special wiring verification method and prototype thereof

Abstract

The invention discloses a double-layer winding special wiring verification method and a prototype thereof, belongs to the technical field of three-phase double-layer winding wiring, and is used for comparison test verification of conventional symmetrical winding wiring and special winding wiring. The method comprises the following steps: firstly, determining the number of slots of a real machine and the number of pole pairs, calculating the number of unit motors, selecting a proper number of unit motors to design an electromagnetic prototype consistent with the characteristics of the pole slots of the real machine, adopting a 0.5-layer coil connection method for the real machine and the prototype, and independently considering potential vectors of upper and lower layers of coils; a prototype is divided into a plurality of branches through a phase belt, conventional wiring and special wiring are respectively realized through two different series combination modes of the branches, and verification of similarity of the two wiring modes and wiring theory correctness is completed. According to the method, verification of two wiring modes is completed by the same electromagnetic prototype, the verification result is effective, the cost is low, a test basis is provided for engineering application of a special wiring technology, optimization of the number of parallel branches of a real machine stator is supported, and the overall performance of the motor is improved.

Description

Technical Field

[0001] This invention relates to the field of wiring technology for three-phase double-layer windings, and specifically to a special wiring verification method for double-layer windings and its prototype. Background Technology

[0002] Pumped storage power stations possess functions such as peak shaving and valley filling, phase regulation, frequency regulation, and emergency backup. Their associated synchronous generators are characterized by frequent start-stop cycles, bidirectional rotation, and high speeds. High-speed synchronous generators correspond to a relatively small number of magnetic poles. Traditional three-phase double-layer winding wiring requires the number of parallel stator branches 'a' to be divisible by the number of poles 2p, i.e., 2p / a must be an integer. According to conventional wiring methods, the electromotive forces of the upper and lower layers are considered as a composite vector, limiting the number of parallel stator branches that can be selected for the unit, and the differences between the number of branches are significant, affecting the selection of overall motor load parameters.

[0003] Taking a 300MW 22-pole pumped storage generator as an example, when connected in a conventional symmetrical manner, the number of branches available is only 1, 2, 11, and 22. Under a rated voltage of 15.75kV, selecting 1 or 2 branches results in branch currents far exceeding the maximum limit of existing air-cooled technology; selecting 11 or 22 branches leads to excessively low branch currents, ultimately requiring sacrifices in hydraulic performance and adjustments to the generator speed to accommodate these changes, resulting in a double loss in both generator performance and cost. If the unit could employ 4 branches, the branch current would be comparable to that of most existing pumped storage units, ensuring both hydraulic performance and reducing generator and power station construction costs.

[0004] In the prior art, Chinese invention patent CN119051318A, published on November 29, 2024, discloses a "wiring method for a 264-slot, 22-pole symmetrical four-branch double-layer three-phase winding." This method treats the potential vector of each individual conductor as a separate vector, ensuring that the number of parallel stator branches 'a' is an integer (4p / a) to achieve symmetrical winding connection, thus overcoming the limitations of traditional wiring methods. However, currently, there is a lack of effective verification methods and devices, making it impossible to accurately verify the similarity between this special wiring method and conventional wiring methods, as well as the correctness of the special wiring theory.

[0005] According to AC winding theory, maintaining the same correspondence between the number of slots and pole pairs in the basic unit and the same arrangement of the stator and rotor windings in the electromagnetic prototype and the final machine ensures that their electromagnetic characteristics are completely identical. This is the fundamental principle for designing electromagnetic prototypes for AC motors. Existing patents also disclose methods for selecting unit motors for unconventional winding motors, such as the Chinese invention patent with publication number CN108959819A, publication date December 7, 2018, entitled "A Method and Device for Selecting Unit Motors for Unconventional Winding Motors." This method can provide unit motor selection schemes for prototype trial production, but it does not propose specific wiring verification methods. It cannot achieve comparative verification of conventional and special wiring on the same electromagnetic prototype. If two prototypes are designed separately for verification, it will significantly increase R&D costs and testing cycles. Summary of the Invention

[0006] The present invention aims to solve the above-mentioned problems existing in the prior art, and provides a verification method and prototype for special wiring of double-layer windings. It enables the comparative test verification of conventional wiring and special wiring of double-layer windings using the same electromagnetic prototype, accurately verifying the similarity between the two wiring methods and the correctness of the special wiring theory, while reducing the verification cost and providing a reliable test basis for the engineering application of special wiring technology.

[0007] To achieve the above-mentioned objectives, the technical solution of the present invention is as follows: A verification method for special wiring of double-layer windings includes the following steps: Step S1: Determine the number of stator slots Z and the number of pole pairs P of the actual machine, and calculate the number of unit motors t of the actual machine, where t is the greatest common divisor of the number of pole pairs P and the number of slots Z; Step S2: Select the number of unit motors n, where n is an integer satisfying 1≤n≤t. Design an electromagnetic prototype based on the number of unit motors n, so that the electromagnetic prototype and the real machine satisfy the same pole-slot characteristics, and the number of slots per pole per phase of the real machine and the electromagnetic prototype are consistent; the number of pole pairs of the electromagnetic prototype is nP / t, and the number of slots is Z'=nZ / t. Step S3: Set the number of parallel branches of the stator of the real machine to a, and the number of poles of the real machine to 2p. a does not satisfy 2p / a being an integer, but satisfies 4p / a being an integer. The number of parallel branches of the stator of the electromagnetic prototype is a'=a / 2, and the number of poles of the electromagnetic prototype is 2p'. a' satisfies 2p' / a' being an integer, but does not satisfy 2p' / a being an integer. Step S4: Consider the potential vectors of the upper and lower sides of the same coil in the electromagnetic prototype separately. Treat the upper and lower coil bars as separate vectors and use the 0.5 layer coil connection method so that half of the upper coil bar and half of the lower coil bar are taken in one branch, and the remaining half of the upper and lower coil bars belong to another branch. Step S5: Divide the potential vector of the 2Z' wire rods of the electromagnetic prototype into six phase bands: A, Z, B, X, C, and Y. Divide the potential vectors contained in the two corresponding phase bands of A and X, B and Y, and C and Z into a parts. Combine each part into a potential vector by series addition, and obtain a branches. Step S6: Based on the above a branches, the three-phase double-layer symmetrical a' branch winding of the electromagnetic prototype is realized by using conventional wiring method and special wiring method respectively, and the similarity and correctness of the wiring theory of conventional wiring and special wiring of double-layer winding are verified.

[0008] Further, in step S6, the three-phase double-layer symmetrical a' branch winding of the electromagnetic prototype is realized by conventional wiring method, including: connecting the two branches that were individually connected to the upper and lower layers of the same slot in step S4 in series to form a composite branch, then connecting the a branches in series to obtain a' branches, the a' branches of phases A and X constitute the U-phase winding, the a' branches of phases B and Y constitute the V-phase winding, and the a' branches of phases C and Z constitute the W-phase winding.

[0009] Furthermore, in step S6, the three-phase double-layer symmetrical a' branch winding of the electromagnetic prototype is realized by special wiring method, including: placing the two branches that were separately connected to the upper and lower layers of the same slot in step S4 into different composite branches, and connecting the a branches in series to obtain a' branches. The a' branches of phases A and X constitute the U-phase winding, the a' branches of phases B and Y constitute the V-phase winding, and the a' branches of phases C and Z constitute the W-phase winding.

[0010] Furthermore, in step S2, when selecting the number of unit motors n, the manufacturing cost of the electromagnetic prototype and the test site factors are taken into account. The smaller n is, the higher the speed and the smaller the size of the electromagnetic prototype. The larger n is, the lower the speed and the larger the size of the electromagnetic prototype.

[0011] Furthermore, in step S4, in each branch of the series-connected rods using the 0.5-layer coil connection method, the number of upper-layer rods and the number of lower-layer rods are the same across all branches.

[0012] Furthermore, in step S6, the branches of each phase winding a' are combined in parallel to form a total potential vector, and each total potential vector is an independent phase winding.

[0013] On the other hand, the present invention also proposes an electromagnetic prototype for realizing the above-mentioned special wiring verification method for double-layer windings. The prototype and the real machine satisfy the same correspondence between the number of slots and the number of pole pairs, and the stator and rotor windings are arranged in the same way. The number of pole pairs of the prototype is nP / t, the number of slots is Z'=nZ / t, n is an integer that satisfies 1≤n≤t, t is the greatest common divisor of the number of pole pairs P and the number of slots Z of the real machine, and the number of slots per pole per phase of the real machine and the prototype are consistent. The number of parallel branches of the stator of the prototype is a'=a / 2, where a is the number of parallel branches of the stator of the actual machine, the number of poles of the prototype is 2p', and a' satisfies that 2p' / a' is an integer, and does not satisfy that 2p' / a is an integer; The prototype is equipped with 2Z' independent potential vector rods, which are evenly divided into six phase bands: A, Z, B, X, C, and Y. It supports a 0.5-layer coil connection method that considers the potential vectors of the upper and lower sides of the same coil separately. It can realize three-phase double-layer symmetrical a' branch windings in both conventional and special connection methods through different series combinations of branches.

[0014] Furthermore, the number of unit motors n in the prototype is less than the number of unit motors t in the actual machine.

[0015] Furthermore, the potential vectors contained in the two phase bands A and X, B and Y, C and Z of the electromagnetic prototype are equally divided into a parts and form a branches. The a branches support two different combination methods of being connected in series, respectively matching the branch synthesis requirements of conventional wiring and special wiring.

[0016] In summary, the present invention has the following advantages: 1. This invention is the first to achieve comparative testing and verification of conventional symmetrical winding connections and special winding connections using the same electromagnetic prototype. It can directly compare the electromagnetic characteristics of the two connection methods, accurately verify the similarity between the special connection method and the conventional connection method, and strongly prove the correctness of the special connection theory, providing a reliable experimental basis for the engineering application of special connection technology.

[0017] 2. This invention selects electromagnetic prototype parameters based on unit motor theory, ensuring that the prototype maintains the same correspondence between the number of slots and pole pairs, the arrangement of stator and rotor windings, and the number of slots per pole and per phase as the real machine. This ensures that the prototype has the same pole and slot characteristics as the real machine, and can truly simulate the electromagnetic performance of the real machine. Its test data can be directly mapped to the design and application of the real machine, and the verification results have high reference value.

[0018] 3. This invention adopts a 0.5-layer coil connection method, which considers the potential vectors of the upper and lower layers of the same coil separately, so that the number of upper and lower layers of the series rods of each branch remains the same in each branch, minimizing the difference in induced potential between branches, improving the symmetry and stability of the winding connection, and providing a standardized implementation method for the branch division of special connections.

[0019] 4. In this invention, the number of unit motors n of the electromagnetic prototype can be flexibly selected within the range of 1≤n≤t, and the design scheme of n<t is preferred, which can effectively reduce the size of the prototype and control the manufacturing cost.

[0020] 5. This invention eliminates the need to design and manufacture two separate prototypes for the two wiring methods, significantly reducing the R&D, prototyping, and testing costs of electromagnetic prototypes and shortening the verification cycle of special wiring technologies. Attached Figure Description

[0021] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments, wherein: Figure 1 is a block diagram of a real machine with special double-layer winding connection (taking phase U as an example). The diagram shows the structure of the real machine where the four branches are directly used as four independent branches.

[0022] Figure 2 is a block diagram of the double-layer winding prototype (taking the U phase as an example). The diagram shows the structure of the prototype with four branches connected in series as two branches.

[0023] Figure 3 is a schematic diagram of the conventional wiring prototype of the double-layer winding (taking the U phase as an example). The diagram shows a conventional wiring structure in which branches 1 and 2 of the prototype are connected in series, and branches 3 and 4 are connected in series and each becomes a branch.

[0024] Figure 4 is a schematic diagram of a prototype scheme for a double-layer winding special connection (taking phase U as an example). The diagram shows a special connection structure in which branches 1 and 3 of the prototype are connected in series, and branches 2 and 4 are connected in series and each becomes a branch.

[0025] Figure 5 is a structural diagram of the electromagnetic prototype, showing the overall structural layout of the electromagnetic prototype.

[0026] In the picture: 1. Wire rod, 2. Terminal, 3. Rotor, 4. Stator. Detailed Implementation

[0027] To more clearly illustrate the present invention, the following description, in conjunction with preferred embodiments and accompanying drawings, further clarifies the invention. Those skilled in the art should understand that the specific description below is illustrative rather than restrictive and should not be construed as limiting the scope of protection of the present invention.

[0028] Example 1 The core difference between single-bar wiring and traditional wiring lies in the number of upper and lower bars. With traditional wiring, each potential vector on the star diagram is a composite vector of the upper and lower bars, so the number of upper and lower bars is exactly the same for each branch and each electrical angle direction. However, with single-bar wiring, each potential vector on the star diagram is the potential vector of a single upper or lower bar, so the number of upper and lower bars is not exactly the same for each branch and each electrical angle direction. Therefore, to simultaneously implement both single-bar wiring and traditional wiring, only the single-bar potential vector can be analyzed. Furthermore, with traditional wiring, the number of upper and lower bars is guaranteed to be exactly the same for each branch and each electrical angle direction, while with single-bar wiring, the number of upper and lower bars is guaranteed to be inconsistent for each branch and each electrical angle direction.

[0029] This invention proposes a special wiring verification method for double-layer windings. The method uses the same electromagnetic prototype to realize both conventional and special wiring of double-layer windings, in order to verify the similarity between the two wiring methods and the correctness of the wiring theory.

[0030] This embodiment uses a 300MW-class 22-pole synchronous generator from a pumped storage power station as the verification object. Combined with a customized electromagnetic prototype, it compares and verifies the conventional and special wiring configurations of the double-layer winding. The invention details a special wiring verification method for double-layer windings and the prototype design logic. The specific implementation steps are as follows: S1. Determine the actual machine parameters and the number of unit motors: The actual machine has 264 stator slots Z, 2p poles 2p = 22, and 11 pole pairs P. Calculate the number of unit motors t, where t is the greatest common divisor of the number of pole pairs P and the number of slots Z, i.e., t = gcd(11, 264) = 11. The corresponding unit motor (t = 1) has 1 pole pair and 24 slots.

[0031] S2. Design of Electromagnetic Prototype: Considering both manufacturing cost and testing site requirements, the number of unit motors is selected as n=3 (1≤n≤11), and an electromagnetic prototype is designed; the number of pole pairs of the prototype is P'=n. P / t= 3 × 11 / 11 = 3, number of poles 2p' = 6; number of prototype slots Z' = n Z / t= 3×264 / 11=72 slots. The number of slots per pole and per phase is consistent between the actual machine and the prototype, and the pole and slot characteristics are the same.

[0032] S3. Set the branch number and pole number adaptation parameters: Set the number of parallel branches of the stator of the real machine to a=4, and verify the adaptability: 2p / a=22 / 4=5.5 (non-integer), 4p / a=44 / 4=11 (integer), which meets the requirements of the real machine parameters; Set the number of parallel branches of the stator of the electromagnetic prototype to a'=a / 2=2, and verify the adaptability: 2p' / a'=6 / 2=3 (integer), 2p' / a=6 / 4=1.5 (non-integer), which meets the requirements of the prototype parameters.

[0033] S4, 0.5 layer coil connection wiring: When wiring the electromagnetic prototype, the potential vectors of the upper and lower sides of the same coil are considered separately. The upper and lower layer bars are treated as separate vectors, and the 0.5 layer coil connection method is adopted. In the prototype, half of the upper layer bar plus half of the lower layer bar is taken from one branch, which is called branch z-1. The remaining half of the upper and lower layer bars are assigned to another branch, which is called branch z-2. This ensures that the number of upper and lower layer bars in each branch is consistent, so as to reduce the difference in induced potential between branches.

[0034] S5. Electromagnetic prototype phase band division and branch synthesis: The potential vector of the prototype 2Z'=144 wire rods is divided into six phase bands: A, Z, B, X, C, and Y. The potential vectors of the corresponding phase bands A and X, B and Y, C and Z are divided into a=4 parts, and each part is synthesized into one potential vector by series addition, resulting in 4 independent branches.

[0035] S6. Implement two wiring methods: Based on 4 independent branches, implement conventional wiring and special wiring respectively. The two branches of each phase winding are connected in parallel and added to synthesize the total potential vector, forming a three-phase double-layer symmetrical two-branch winding.

[0036] Taking phase U as an example, the connection method of phases V and W is the same as that of phase U: Conventional wiring method: Connect branch z-1 and branch z-2 directly in series to form a combined branch. For example... Figure 3 As shown, branches 1 and 2 are connected in series to form one branch, and branches 3 and 4 are connected in series to form another branch, ensuring that the number of upper and lower layer bars in each electrical angle direction of each branch is completely consistent. Special wiring method: The z-1 branch and z-2 branch are placed in different composite branches. For example... Figure 4 As shown, branches 1 and 3 are connected in series to form one branch, and branches 2 and 4 are connected in series to form another branch, so that the number of upper and lower layer bars in each electrical angle direction of each branch is not completely consistent.

[0037] S7. Verification and Implementation: Using the above-mentioned 72-slot 6-pole electromagnetic prototype, wiring, debugging, and comparative tests were completed for both conventional and special wiring. Key indicators such as winding induced electromotive force, magnetomotive force harmonic content, and branch current balance under the two wiring methods were tested, verifying the similarity between conventional and special wiring of double-layer windings. At the same time, it also confirmed the correctness of the special wiring theory (symmetrical wiring can be achieved when 4p / a is an integer).

[0038] Example 2 This embodiment provides an electromagnetic prototype for implementing the verification method described in Embodiment 1, such as... Figure 5As shown, the prototype has a 72-slot, 6-pole structure, which satisfies the same correspondence between the number of slots and pole pairs as the 264-slot, 22-pole prototype, and the stator and rotor windings are arranged in the same way. The prototype has 3 pole pairs and 72 slots, and the number of unit motors selected is n=3. The number of slots per pole and per phase of the prototype and the prototype are consistent.

[0039] The number of parallel branches in the stator of the prototype is a'=2, the number of parallel branches in the stator of the actual machine is a=4, the number of poles of the prototype is 2p'=6, and 2p' / a'=3 is an integer and 2p' / a=1.5 is a non-integer, which meets the parameter adaptation requirements.

[0040] The prototype is equipped with 144 independent potential vector rods. The rods are evenly divided into six phase bands: A, Z, B, X, C, and Y. It also supports a 0.5-layer coil connection method that considers the potential vectors of the upper and lower sides of the same coil separately. The potential vectors of the corresponding phase bands can be evenly divided into four parts to form four independent branches.

[0041] The four independent branches support two different combinations of series connection in pairs. One is series connection of branches on the same path (1 and 2 in series, 3 and 4 in series), which matches the branch combination requirements of conventional wiring. The other is cross-series connection of branches on different paths (1 and 3 in series, 2 and 4 in series), which matches the branch combination requirements of special wiring. It can realize three-phase double-layer symmetrical two-branch windings in both conventional and special wiring methods through different series connection combinations of branches, and complete the comparison and verification of the two wiring methods.

[0042] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A verification method for special wiring of double-layer windings, characterized in that, Includes the following steps: Step S1: Determine the number of stator slots Z and the number of pole pairs P of the actual machine, and calculate the number of unit motors t of the actual machine, where t is the greatest common divisor of the number of pole pairs P and the number of slots Z; Step S2: Select the number of unit motors n, where n is an integer satisfying 1≤n≤t. Design an electromagnetic prototype based on the number of unit motors n, so that the electromagnetic prototype and the real machine satisfy the same pole-slot characteristics, and the number of slots per pole per phase of the real machine and the electromagnetic prototype are consistent; the number of pole pairs of the electromagnetic prototype is nP / t, and the number of slots is Z'=nZ / t. Step S3: Set the number of parallel branches of the stator of the real machine to a, and the number of poles of the real machine to 2p. a does not satisfy 2p / a being an integer, but satisfies 4p / a being an integer. The number of parallel branches of the stator of the electromagnetic prototype is a'=a / 2, and the number of poles of the electromagnetic prototype is 2p'. a' satisfies 2p' / a' being an integer, but does not satisfy 2p' / a being an integer. Step S4: Consider the potential vectors of the upper and lower sides of the same coil in the electromagnetic prototype separately. Treat the upper and lower coil bars as separate vectors and use the 0.5 layer coil connection method so that half of the upper coil bar and half of the lower coil bar are taken in one branch, and the remaining half of the upper and lower coil bars belong to another branch. Step S5: Divide the potential vector of the 2Z' wire rods of the electromagnetic prototype into six phase bands: A, Z, B, X, C, and Y. Divide the potential vectors contained in the two corresponding phase bands of A and X, B and Y, and C and Z into a parts. Combine each part into a potential vector by series addition, and obtain a branches. Step S6: Based on the above a branches, the three-phase double-layer symmetrical a' branch winding of the electromagnetic prototype is realized by using conventional wiring method and special wiring method respectively, and the similarity and correctness of the wiring theory of conventional wiring and special wiring of double-layer winding are verified.

2. The verification method for special wiring of double-layer windings as described in claim 1, characterized in that, In step S6, the three-phase double-layer symmetrical a' branch winding of the electromagnetic prototype is realized by conventional wiring method, including: connecting two branches that were individually connected to the upper and lower layers of the same slot in step S4 in series to form a composite branch, then connecting a branches in pairs to obtain a' branches, the a' branches of phases A and X constitute the U-phase winding, the a' branches of phases B and Y constitute the V-phase winding, and the a' branches of phases C and Z constitute the W-phase winding.

3. The verification method for special wiring of double-layer windings as described in claim 1, characterized in that, In step S6, the three-phase double-layer symmetrical a' branch winding of the electromagnetic prototype is realized by special wiring method, including: placing the two branches that were separately connected to the upper and lower layers of the same slot in step S4 into different composite branches, and connecting a branches in series to obtain a' branches. The a' branches of phases A and X constitute the U phase winding, the a' branches of phases B and Y constitute the V phase winding, and the a' branches of phases C and Z constitute the W phase winding.

4. The verification method for special wiring of double-layer windings as described in claim 1, characterized in that, In step S2, when selecting the number of unit motors n, the manufacturing cost of the electromagnetic prototype and the test site factors are taken into account. The smaller n is, the higher the speed and the smaller the size of the electromagnetic prototype. The larger n is, the lower the speed and the larger the size of the electromagnetic prototype.

5. The verification method for special wiring of double-layer windings as described in claim 1, characterized in that, In step S4, in each branch of the series-connected rods using the 0.5-layer coil connection method, the number of upper-layer rods and the number of lower-layer rods are the same across all branches.

6. The verification method for special wiring of double-layer windings as described in claim 1, characterized in that, In step S6, the branches of each phase winding a' are combined in parallel to form a total potential vector, and each total potential vector is an independent phase winding.

7. An electromagnetic prototype implementing the special wiring verification method for double-layer windings as described in any one of claims 1-6, characterized in that, The prototype and the real machine satisfy the same correspondence between the number of slots and the number of pole pairs, and the stator and rotor windings are arranged in the same way; the number of pole pairs of the prototype is nP / t, the number of slots is Z'=nZ / t, n is an integer that satisfies 1≤n≤t, t is the greatest common divisor of the number of pole pairs P and the number of slots Z of the real machine, and the number of slots per pole per phase of the real machine and the prototype are consistent. The number of parallel branches of the stator of the prototype is a'=a / 2, where a is the number of parallel branches of the stator of the actual machine, the number of poles of the prototype is 2p', and a' satisfies that 2p' / a' is an integer, and does not satisfy that 2p' / a is an integer; The prototype is equipped with 2Z' independent potential vector rods, which are evenly divided into six phase bands: A, Z, B, X, C, and Y. It supports a 0.5-layer coil connection method that considers the potential vectors of the upper and lower sides of the same coil separately. It can realize three-phase double-layer symmetrical a' branch windings in both conventional and special connection methods through different series combinations of branches.

8. The electromagnetic prototype as described in claim 7, characterized in that, The number of unit motors n in the prototype is less than the number of unit motors t in the final product.

9. The electromagnetic prototype as described in claim 7, characterized in that, The electromagnetic prototype's A and X, B and Y, C and Z correspond to two phase bands, each containing a potential vector that are equally divided into a parts and form a branches. These a branches support two different combinations connected in series, respectively matching the branch synthesis requirements of conventional wiring and special wiring.

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