Rotor winding of wound brushless doubly-fed motor

Abstract

The invention provides a rotor winding of a winding type brushless doubly-fed motor, which is designed according to the natural attribute of tooth harmonic waves, adopts a winding type winding, has the pole pair number ratio of 1: 3 and the rotor slot number of 88 slots, has two phases and is divided into four branches, each branch coil is divided into three coil groups, the coil span of the two coil groups is 14, and the coil span of the two coil groups is 14. The coil span of the other coil group is 36, and the coil slot numbers of each coil group are distributed in sequence and are connected in series to form a closed loop. The rotor winding is designed according to the tooth harmonic principle, multi-phase windings with different pole pair numbers are integrally considered, the arrangement characteristic of a conventional winding type single-turn double-layer coil is kept, wiring is standard and orderly, the winding structure and the manufacturing process are simplified, the defects of an original winding type rotor winding are overcome, the harmonic content is small, the power density is improved, and operation is reliable.

Description

Technical Field

[0001] The present invention relates to the technical field of motors, and more specifically, to a rotor winding of a wound-type brushless doubly-fed motor. The rotor winding coils adopt a new arrangement and connection method to obtain better technical characteristics. Background Art

[0002] Brushless doubly-fed motors are powered by both the grid and a variable-frequency power supply. They offer reliable operation, require a relatively small variable-frequency power supply, and can operate at varying voltage levels. They can operate as both a motor with variable-frequency speed regulation and a generator, suitable for applications such as wind or hydropower variable-speed constant-frequency power generation.

[0003] The stator winding of a brushless doubly-fed motor (BDF) has two pole pairs, p1 and p2. This requires the rotor winding to simultaneously generate magnetomotive force waves with pole pairs p1 and p2 rotating in opposite directions, and to have the highest possible winding coefficient for both pole pairs. The key to the good performance of a BDF motor lies in the rotor. For a wound rotor with multiphase windings arranged in slots, the windings can, in principle, be composed of two sets of multiphase windings, p1 and p2, connected in series. The ratio of the pole pairs p1 and p2 can be selected based on actual conditions. However, wound rotor windings with a pole ratio of 1:3 present complex manufacturing processes and present numerous challenges, such as low power density. Summary of the Invention

[0004] The present invention aims to solve the technical problems existing in the prior art and provides a rotor winding for a wound-type brushless doubly-fed motor, so as to overcome the problems of the prior art such as the complicated manufacturing process of the rotor winding and the low power density.

[0005] The present invention provides a rotor winding for a wound-type brushless doubly-fed motor. The rotor winding has a pole pair ratio of 1:3 and 88 rotor slots. The rotor winding is two-phase and is divided into four parallel branch coils, wherein each branch coil is divided into three coil groups, wherein the coil span of two coil groups is 14, and the coil span of the other coil group is 36. The multiple coils contained in each coil group are distributed sequentially, and the different coil groups in each branch are connected end to end to form a closed loop.

[0006] On the basis of the above technical solution, the present invention can also make the following improvements.

[0007] Optionally, using the tooth harmonic principle, designs are performed for the pole pairs p1=1 and p2=3 respectively to obtain the slot numbers of the two winding parts, each slot number representing a coil;

[0008] Among them, for span 36, the slot numbers of the coils contained in each of the four parallel branch coils are: coil group A: [10, 11, 12, 13, 14, 15, 16, 17], coil group B: [54, 55, 56, 57, 58, 59, 60, 61], coil group C: [32, 33, 34, 35, 36, 37, 38, 39], coil group D: [76, 77, 78, 79, 80, 81, 82, 83];

[0009] For span 14, the slot numbers of these four branches are: coil group a1: [10, 11, 12, 13], coil group a2: [36, 37, 38, 39], coil group b1: [54, 55, 56, 57], coil group b2: [80, 81, 82, 83], coil group c1: [32, 33, 34, 35], coil group c2 [58, 59, 60, 61], coil group d1: [76, 77, 78, 79], coil group d2: [14, 15, 16, 17];

[0010] The three coil groups in each branch coil are connected end to end to form a closed loop, and the multiple coils in each coil group are connected in series in sequence.

[0011] Optionally, the coil side in the rotor slot is double-layered, and for the pole pair number p1=1, the winding coefficient is 0.6165; for the pole pair number p2=3, the winding coefficient is 0.7434; relative to the pole pair number p2=3, the maximum relative amplitude of the winding magnetomotive force harmonic is 5.992%.

[0012] The present invention provides a rotor winding for a wound-type brushless doubly-fed motor. This rotor winding is designed using the tooth harmonic principle, taking into account two sets of multi-phase windings with pole pairs p1 and p2 as a whole, maintaining the layout characteristics of a conventional wound-type single-turn double-layer coil, and providing standardized and orderly wiring. This simplifies the winding structure and manufacturing process, overcomes the defects of the original wound-type rotor winding, has low harmonic content, improved power density, and reliable operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 The figure is a schematic structural diagram of the rotor winding of a linear brushless doubly-fed motor according to an embodiment of the present invention. DETAILED DESCRIPTION

[0014] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. In addition, the technical features in the various embodiments or single embodiments provided by the present invention can be arbitrarily combined with each other to form a feasible technical solution. This combination is not restricted by the sequence of steps and / or structural composition mode, but must be based on the ability of ordinary technicians in this field to implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0015] Figure 1 A schematic structural diagram of a rotor winding of a wound-type brushless doubly-fed motor provided in an embodiment of the present invention, wherein the pole pair ratio of the rotor winding is 1:3. For the pole pair numbers p1=1 and p2=3, in order to obtain a winding scheme with high winding conductor utilization, low harmonic content, and simple wiring under the two pole numbers, the number of rotor slots in the embodiment of the present invention is 88 slots. By using the tooth harmonic principle, the pole pair numbers p1=1 and p2=3 can be designed respectively to obtain the slot numbers corresponding to the two parts of the winding (where each slot number represents a coil). Note that a winding scheme in which the coils in the coil group are distributed sequentially should be selected at this time, and then the two parts are connected in series into a whole.

[0016] Based on the principles of winding tooth harmonic design, this rotor winding is divided into two phases, each with four parallel branches. Each branch includes multiple coil groups with different coil spans. In this embodiment of the present invention, each branch includes three coil groups, each with two spans: 36 and 14. Specifically, two of the three coil groups have a span of 14, and one has a span of 36. The coil group with a span of 36 is located between the two coil groups with a span of 14.

[0017] Among them, for span 36, the slot numbers of the coils contained in each of the four parallel branch coils are: coil group A: [10, 11, 12, 13, 14, 15, 16, 17], coil group B: [54, 55, 56, 57, 58, 59, 60, 61], coil group C: [32, 33, 34, 35, 36, 37, 38, 39], coil group D: [76, 77, 78, 79, 80, 81, 82, 83];

[0018] For span 14, the slot numbers of these four branches are: coil group a1: [10, 11, 12, 13], coil group a2: [36, 37, 38, 39], coil group b1: [54, 55, 56, 57], coil group b2: [80, 81, 82, 83], coil group c1: [32, 33, 34, 35], coil group c2 [58, 59, 60, 61], coil group d1: [76, 77, 78, 79], coil group d2: [14, 15, 16, 17].

[0019] The first branch consists of three coil groups: a1, A, and a2; the second branch consists of three coil groups: b1, B, and b2; the third branch consists of three coil groups: c1, C, and c2; and the fourth branch consists of three coil groups: d1, D, and d2. The three coils in each branch are connected end-to-end to form a closed loop, and the multiple coils in each coil group are connected sequentially.

[0020] The wiring diagram is as follows Figure 1 As shown, it can be seen that the slot numbers of each branch of the two different coil pitches are sequentially continuous and present a very regular distribution.

[0021] Figure 1 The coil pitch y = 14 in coil groups a1 and a2, b1 and b2, c1 and c2, and d1 and d2, and the coil pitch y = 36 in coil groups A, B, C, and D. For a pole pair number p1 = 1, the winding coefficient is 0.6165; for a pole pair number p2 = 3, the winding coefficient is 0.7434, and the maximum relative amplitude of the winding magnetomotive force harmonics does not exceed 5.992% (relative to the pole pair number p2 = 3). These two windings are single-layer windings for spans 36 and 14, respectively. This means that the rotor winding as a whole is a double-layer winding, with the coils within each coil group arranged sequentially. This connection method offers simple wiring, excellent processability, improved winding conductor utilization, reduced harmonic content, increased power density, and reliable operation.

[0022] The present invention provides a rotor winding for a wound-type brushless doubly-fed motor. Each branch coil of the rotor winding is divided into multiple coil groups, and the multiple coil groups of each branch coil are designed to have different coil spans. The multiple coils contained in each coil group are sequentially distributed, and the different coil groups of each branch are connected end-to-end to form a closed loop. The rotor winding of the present invention utilizes the principle of tooth harmonics to design, comprehensively considering multi-phase windings with different pole pairs. While maintaining the characteristics of a conventional wound-type single-turn double-layer coil arrangement, the wiring is standardized and orderly, simplifying the winding structure and manufacturing process. This overcomes the shortcomings of existing wound-type rotor windings, reduces harmonic content, improves power density, and ensures reliable operation.

[0023] It should be noted that, in the above embodiments, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant description of other embodiments.

[0024] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0025] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A rotor winding of a wound-type brushless doubly-fed motor, characterized in that: The pole pair ratio of the rotor winding is 1:3, the number of rotor slots is 88, the rotor winding is two-phase, and is divided into 4 parallel branch coils. Each branch coil is divided into 3 coil groups, of which the coil span of two coil groups is 14, and the coil span of the other coil group is 36. The multiple coils contained in each coil group are distributed sequentially, and the different coil groups in each branch are connected end to end to form a closed loop.

2. The rotor winding of the wound-type brushless doubly-fed motor according to claim 1, characterized in that: Using the tooth harmonic principle, the pole pairs p1 = 1 and p2 = 3 are designed to obtain the slot numbers of the two windings. Each slot number represents a coil. Among them, for span 36, the slot numbers of the coils contained in each of the four parallel branch coils are: coil group A: [10, 11, 12, 13, 14, 15, 16, 17], coil group B: [54, 55, 56, 57, 58, 59, 60, 61], coil group C: [32, 33, 34, 35, 36, 37, 38, 39], coil group D: [76, 77, 78, 79, 80, 81, 82, 83]; For span 14, the slot numbers of these four branches are: coil group a1: [10, 11, 12, 13], coil group a2: [36, 37, 38, 39], coil group b1: [54, 55, 56, 57], coil group b2: [80, 81, 82, 83], coil group c1: [32, 33, 34, 35], coil group c2 [58, 59, 60, 61], coil group d1: [76, 77, 78, 79], coil group d2: [14, 15, 16, 17]; The three coil groups in each branch coil are connected end to end to form a closed loop, and the multiple coils in each coil group are connected in series in sequence.

3. The rotor winding of the wound-type brushless doubly-fed motor according to claim 2, characterized in that: The coil side in the rotor slot is double-layered, and for the number of pole pairs p1=1 ， Winding coefficient 0.6165; for pole pair number p2 = 3 ， Winding coefficient 0.7434; relative pole pair number p2 = 3 ， The maximum relative amplitude of the winding magnetomotive force harmonics is 5.992%.

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