Wound-type brushless double-fed motor rotor winding design method, winding and motor

Abstract

The invention discloses a method for designing a rotor winding of a wound brushless double-fed motor, a winding and a motor, and belongs to the field of motor winding design. The method comprises: S1, merging and drawing two single-pole logarithmic slot number phase diagrams together to obtain a bipolar logarithmic slot number phase diagram; S2, dividing the bipolar logarithmic slot number phase diagram into a plurality of block diagrams with the same distribution structure based on a preset division scale; S3, selecting a block diagram with the goal of generating two magnetomotive forces with different pole pairs and opposite rotation directions, and the slot number of the selected block diagram is the middle slot number of the rotor winding; S4, setting a new preset division scale and repeatedly executing S2-S3 until N groups of middle slot numbers are obtained, where N is a preset value not less than 2; S5, taking the same current direction at each location in the slot as a constraint, superimposing the middle slot numbers of the rotor winding of the same phase in an axis alignment manner to obtain the final slot number of the rotor winding of each phase. The flexibility of rotor winding design is improved.

Description

Technical Field

[0001] The present invention belongs to the field of motor winding design, and more specifically, relates to a design method for a wound-type brushless double-fed motor rotor winding, a winding and a motor. Background Art

[0002] There are two sets of windings with different pole pairs on the stator of the brushless doubly fed motor, namely, p The power winding and the number of pole pairs is p c The control winding of the two sets of windings is indirectly coupled through a specially designed rotor, thereby realizing energy transfer between the two sets of windings. The rotor structure is the core part of the brushless doubly-fed motor design and is also a key factor affecting the motor performance. Currently, there are three main structures: concentric cage type, reluctance type and winding type. The winding rotor structure stands out among many rotor structures due to its smaller harmonic content and better motor operation performance.

[0003] At present, the winding design of the wound rotor structure of the brushless doubly fed motor is mainly based on the tooth harmonic principle in the AC motor winding theory. This design method has the following shortcomings: the number of basic slots of the designed rotor is very small, resulting in a large number of harmonics and large harmonic components; there are many types of rotor coils and the coils are arranged irregularly, resulting in very complicated manufacturing and offline processes; the number of winding phases and the number of rotor slots are strictly restricted by the combination of two pole pairs, which restricts the flexibility of the rotor winding structure design and the optimization and improvement of motor performance; the design scheme is not intuitive enough, and it is impossible to intuitively obtain a winding scheme with good symmetry and a high distribution coefficient for both magnetic field pole pairs. It must be repeatedly tested many times, which greatly limits the flexibility and extensiveness of the rotor winding design scheme. In addition, the quality of the scheme obtained by this design method depends to a large extent on the subjective experience of the designer, which has great limitations. Summary of the invention

[0004] In view of the defects of the prior art and the need for improvement, the present invention provides a rotor winding design method, winding and motor for a wound-type brushless doubly-fed motor, the purpose of which is to overcome the limitations of the tooth harmonic design principle and improve the flexibility of the rotor winding design.

[0005] To achieve the above object, according to one aspect of the present invention, a method for designing a rotor winding of a wound-type brushless doubly-fed motor is provided, comprising: S1, merging and drawing two single-pole logarithmic slot number phase diagrams together to obtain a double-pole logarithmic slot number phase diagram, wherein the two single-pole logarithmic slot number phase diagrams represent p p Pole pair number, p cSlot number phase diagram of the number of pole pairs; S2, dividing the bipolar pair slot number phase diagram into multiple block diagrams with the same distribution structure based on a preset division scale; S3, selecting a block diagram with the goal of generating two magnetomotive forces with different pole pairs and opposite rotation directions, and the slot number of the selected block diagram is the middle slot number of the rotor winding; S4, setting a new preset division scale and repeatedly executing S2-S3 until N groups of middle slot numbers are obtained, where N is a preset value not less than 2; S5, with the constraint that the current direction at each location in the slot is the same, the middle slot numbers of the rotor winding of the same phase are superimposed in an axial alignment manner to obtain the final slot number of the rotor winding of each phase.

[0006] Furthermore, the preset division scale includes the number of rotor winding phases and phase bands, and S2 includes: based on the phase difference between the rotor windings of each phase, dividing the bipolar logarithmic slot number phase diagram in the first direction according to the phase band, and dividing the bipolar logarithmic slot number phase diagram in the second direction according to the number of rotor winding phases, to obtain multiple block diagrams with the same distribution structure, the first direction is one of the horizontal and vertical directions, and the second direction is the other of the horizontal and vertical directions.

[0007] Furthermore, after the division, the block diagrams in the same first direction are different block diagram schemes of the same-phase rotor winding, and S3 also includes: for the block diagram selected for any phase rotor winding, part of the rotor winding of the selected block diagram is replaced with the corresponding rotor winding in other block diagram schemes of the any phase rotor winding, the same phase is directly replaced, and the opposite phase is replaced by reverse connection.

[0008] Furthermore, the number of phases of the rotor winding is ≥3.

[0009] Furthermore, after S5, the step further includes: dividing each phase rotor winding into two parts, wherein one part of each phase rotor winding is connected in a star connection, and the other part of each phase winding is connected in a delta connection.

[0010] According to another aspect of the present invention, there is provided a wound-type brushless double-fed motor rotor winding, which is obtained by the wound-type brushless double-fed motor rotor winding design method described above.

[0011] According to another aspect of the present invention, there is provided a wound-rotor brushless doubly-fed motor, characterized in that it comprises the above-mentioned wound-rotor brushless doubly-fed motor rotor winding.

[0012] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects: a new method for designing the rotor winding of a wound-type brushless doubly-fed motor is proposed, a single-winding, bipolar pair symmetric, flexible multi-phase wound-type rotor is designed by using a bipolar logarithmic slot number phase diagram, and based on the pole-changing winding theory, a pair of p is defined under the bipolar logarithmic slot number phase diagram. p 、p cA multi-phase symmetrical slot number block with two uniformly symmetrical pole pairs is used to construct a single-winding rotor winding structure with self-closing induced current, simplifying the rotor winding structure. A block diagram with exactly the same distribution structure is constructed using a bipolar pair slot number phase diagram, which can simultaneously display two pole pairs. The rotor winding based on this has a completely symmetrical structure no matter from which pole pair number it is viewed, and will not produce unbalanced potential. It can well meet the requirements of the rotor winding to simultaneously generate two magnetic motive forces with symmetrical pole pairs and opposite rotation directions, and can achieve the goal of low harmonics, strong coupling, and flexible adjustment of the relative amplitude of the bipolar pair rotating magnetic motive force of the rotor winding. The rotor winding slot number, phase number, pole pair number, etc. can be flexibly matched and designed; further, the magnetic motive force of the scheme can be increased by superimposing different arrangement schemes. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 A flow chart of a method for designing a rotor winding of a wound-type brushless double-fed motor provided by an embodiment of the present invention;

[0014] Figure 2 A schematic diagram of the structure of the stator / rotor winding of a brushless doubly-fed motor provided in an embodiment of the present invention;

[0015] Figure 3A A schematic diagram of the rotor winding slot number designed for a 180° phase band and three-phase rotor winding according to an embodiment of the present invention;

[0016] Figure 3B A schematic diagram of the rotor winding slot number designed for a 120° phase band and three-phase rotor winding according to an embodiment of the present invention;

[0017] Figure 3C A schematic diagram of the rotor winding slot number designed for a 72° phase band and a five-phase rotor winding according to an embodiment of the present invention;

[0018] Figure 4A A schematic diagram of the rotation direction of the magnetomotive force of the three-phase rotor winding under different pole pair numbers provided by an embodiment of the present invention;

[0019] Figure 4B Schematic diagram of the rotation direction of the magnetomotive force of the five-phase rotor winding under different pole pair numbers provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0020] 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.

[0021] In the present invention, the terms "first", "second", etc. (if any) in the present invention and the accompanying drawings are used to distinguish similar objects but not necessarily to describe a specific order or sequence.

[0022] Figure 1 A flow chart of a method for designing a rotor winding of a wound-type brushless double-fed motor provided by an embodiment of the present invention. Figure 1 , combined with Figure 2-4B , the rotor winding design method of the wound-type brushless doubly-fed motor in this embodiment is described in detail, and the method includes operations S1 to S5.

[0023] Operation S1, the two unipolar logarithmic slot number phase diagrams are combined and plotted together to obtain a bipolar logarithmic slot number phase diagram. The two unipolar logarithmic slot number phase diagrams represent p p Pole pair number, p c Phase diagram of the number of pole pairs versus the slot number.

[0024] The structural principle of the wound-rotor brushless double-fed motor is as follows Figure 2 As shown, in order to design its special rotor winding arrangement, in this embodiment, the two single-pole-pair slot number phase diagrams are firstly combined and drawn together, that is, the slot number distribution under two pole pairs is simultaneously shown on the same slot number phase diagram.

[0025] Operation S2: dividing the bipolar logarithmic slot number phase diagram into a plurality of block diagrams with the same distribution structure based on a preset division scale.

[0026] According to an embodiment of the present invention, the preset division scale includes the number of rotor winding phases and phase bands, and operation S2 includes: based on the phase difference between the rotor windings of each phase, dividing the bipolar logarithmic slot number phase diagram in a first direction according to the phase band, dividing the bipolar logarithmic slot number phase diagram in a second direction according to the number of rotor winding phases, and obtaining a plurality of block diagrams with the same distribution structure, wherein the first direction is one of the horizontal and vertical directions, and the second direction is the other of the horizontal and vertical directions. Preferably, the number of rotor winding phases is ≥3.

[0027] By partitioning the graph, we can obtain block graphs with exactly the same distribution structure, which have good structural distribution symmetry. Figure 3A , shows the block diagram obtained when the rotor winding has three phases and the phase band is 180°, including the block diagram A1 and the block diagram A2 of the A-phase rotor winding, the block diagram B1 and the block diagram B2 of the B-phase rotor winding, and the block diagram C1 and the block diagram C2 of the C-phase rotor winding. Figure 3B , shows the block diagram obtained when the rotor winding phase number is three-phase and the phase band is 120°, including the block diagram A1, block diagram A2 and block diagram A3 of the A-phase rotor winding, the block diagram B1, block diagram B2 and block diagram B3 of the B-phase rotor winding, and the block diagram C1, block diagram C2 and block diagram C3 of the C-phase rotor winding. Figure 3C , shows the block diagram obtained when the rotor winding has five phases and the phase band is 72°, including block diagrams A1 to A5 of the A-phase rotor winding, block diagrams B1 to B5 of the B-phase rotor winding, and block diagrams C1 to C5 of the C-phase rotor winding.

[0028] Operation S3, selecting a block diagram with the goal of generating two magnetomotive forces with different pole pairs and opposite rotation directions, and the slot number of the selected block diagram is the middle slot number of the rotor winding.

[0029] By optimizing the block diagram in the dual-pole-pair slot number phase diagram, the slot number that can simultaneously generate two pole pairs with opposite rotation directions can be defined. Figure 3A , when selecting the slot number in the A1-B1-C1 block diagram, from the p1 pole (i.e. p p From the p2 pole (i.e. p c From the perspective of the pole, a magnetomotive force can be formed that is divided into 180° phase bands and rotates along the direction of A1→C1→B1. Figure 3B By selecting the A1-B1-C1 block, a rotor winding slot number scheme with a higher winding coefficient can be obtained. Figure 3C Through the combination of A1-B1-C1-D1-E1, a five-phase winding scheme can be formed. Looking from the p2 pole and the p1 pole, the magnetomotive force rotates along the directions of A1→E1→D1→C1→B1 and A1→B1→C1→D1→E1 respectively.

[0030] It can be seen that the blocks selected from the above two-pole logarithmic slot number phase diagram, no matter which pole pair is viewed from, their winding structure will be symmetrical, and the multi-phase windings formed under the two pole pairs are just the symmetrical structure of the reverse phase sequence. If the windings formed by each block are self-short-circuited and closed, the rotor winding will form a single set of self-short-circuited closed windings. This single winding structure can be equivalent to two sets of windings connected in series with reverse phase sequence. No matter which pole pair is viewed from, the induced rotor current will act simultaneously in the self-closed loop to generate two magnetic motive forces with different pole pairs and opposite rotation directions, such as Figure 4A and Figure 4B This rotor winding structure is simple and has a clear loop relationship, which can avoid the complex connection relationship of the pole-changing winding in the conventional pole-changing motor.

[0031] According to an embodiment of the present invention, the block diagrams in the same first direction after division are different block diagram schemes of the same-phase rotor winding, and operation S3 further includes: for the block diagram selected for any phase rotor winding, replacing part of the rotor winding of the selected block diagram with the corresponding rotor winding in other block diagram schemes of any phase rotor winding, directly replacing the same phase, and replacing the opposite phase with reverse connection. That is, for example, part of the winding of the A1 block diagram can be replaced with the corresponding winding in the A2 block diagram, further increasing the flexibility of the winding connection.

[0032] Operation S4, setting a new preset division scale and repeatedly performing operations S2 to S3, until N groups of intermediate slot numbers are obtained, where N is a preset value not less than 2.

[0033] Specifically, the number of phases and / or phase bands of the rotor winding are changed, and the rotor winding scheme generating method in the above operations S2 to S3 is repeatedly performed, so as to obtain N different rotor winding schemes.

[0034] Operation S5, with the constraint that the current directions at all locations in the slots are the same, the intermediate slot numbers of the rotor windings of the same phase are superimposed in an axis-aligned manner to obtain the final slot numbers of the rotor windings of each phase.

[0035] Taking N=2 as an example, for example, the axis is aligned Figure 3A and Figure 3B The winding scheme iron frame in the winding scheme can further increase the magnetomotive force of the winding scheme, but it should be noted that the current direction in each slot cannot be opposite, and the corresponding windings in each winding scheme are connected in parallel.

[0036] According to an embodiment of the present invention, after operation S5, the method further includes: dividing each phase rotor winding into two parts, wherein one part of each phase rotor winding is connected in star connection, and the other part of each phase winding is connected in delta connection, so as to weaken the harmonics of the winding.

[0037] The method for designing the rotor winding of a brushless double-fed motor in the embodiment of the present invention can be realized by using the alternating current motor winding pole change theory. p and p c The design is carried out in terms of the selection of two pole pairs, the number of winding phases, the winding distribution coefficient, the harmonic content, etc. This principle and method is implemented by compiling a computer program, adding constraint equations such as symmetry and non-repetitive selection of slot numbers, to realize the computerization of the slot number selection under two pole pairs. This will greatly expand the dimension and flexibility of winding design, thereby bringing about the optimization design of motor performance.

[0038] The embodiment of the present invention also provides a wound-type brushless double-fed motor rotor winding, comprising Figure 1-4B The rotor winding design method of the wound-rotor brushless doubly-fed motor is obtained.

[0039] The embodiment of the present invention also provides a wound-rotor brushless double-fed motor, comprising Figure 1-4B The rotor winding of a brushless double-fed motor obtained by the rotor winding design method of the brushless double-fed motor shown in the figure.

[0040] 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 method for designing rotor windings of a wound-type brushless double-fed motor, characterized in that: include: S1, the two unipolar logarithmic slot number phase diagrams are combined and plotted together to obtain a bipolar logarithmic slot number phase diagram, where the two unipolar logarithmic slot number phase diagrams represent p p Pole pair number, p c Slot number phase diagram of pole pair number; S2, dividing the bipolar logarithmic slot number phase diagram into a plurality of block diagrams with the same distribution structure based on a preset division scale; S3, selecting a block diagram with the goal of generating two magnetomotive forces with different pole pairs and opposite rotation directions, and the slot number of the selected block diagram is the middle slot number of the rotor winding; S4, setting a new preset division scale and repeatedly executing S2-S3 until N groups of intermediate slot numbers are obtained, where N is a preset value not less than 2; S5, with the current direction in each slot being the same as a constraint, the intermediate slot numbers of the rotor winding of the same phase are superimposed by axial alignment to obtain the final slot number of the rotor winding of each phase.

2. The method for designing a rotor winding of a wound-rotor brushless doubly-fed motor according to claim 1, characterized in that: The preset division scale includes the number of rotor winding phases and phase belts, and S2 includes: Based on the phase difference between the rotor windings of each phase, the bipolar logarithmic slot number phase diagram is divided in the first direction according to the phase band, and the bipolar logarithmic slot number phase diagram is divided in the second direction according to the phase number of the rotor winding, so as to obtain multiple block diagrams with the same distribution structure, wherein the first direction is one of the horizontal and vertical directions, and the second direction is the other of the horizontal and vertical directions.

3. The method for designing rotor windings of a wound-rotor brushless double-fed motor according to claim 2, characterized in that: After the division, the block diagrams in the same first direction are different block diagram schemes of the same-phase rotor winding. S3 also includes: for the block diagram selected for any phase rotor winding, part of the rotor winding of the selected block diagram is replaced with the corresponding rotor winding in other block diagram schemes of the any phase rotor winding, the same phase is directly replaced, and the opposite phase is replaced by reverse connection.

4. The method for designing rotor windings of a wound-rotor brushless doubly-fed motor according to claim 2, characterized in that: The number of phases of the rotor winding is ≥3.

5. The method for designing rotor windings of a wound-rotor brushless doubly-fed motor according to claim 1, characterized in that: After S5, the method further includes: dividing each phase rotor winding into two parts, wherein one part of each phase rotor winding is connected in star connection, and the other part of each phase winding is connected in delta connection.

6. A wound brushless double-fed motor rotor winding, characterized in that: Obtained by the rotor winding design method of a wound-type brushless doubly-fed motor as described in any one of claims 1-5.

7. A wound-rotor brushless double-fed motor, characterized in that: It includes the wound-type brushless double-fed motor rotor winding as described in claim 6.

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