Six-phase motor and harmonic suppression hybrid winding design method thereof

Abstract

The invention discloses a six-phase motor and a harmonic suppression hybrid winding design method thereof, and relates to the technical field of motors, and the method comprises the steps: obtaining a slot vector star diagram under six-phase current phase difference optimization based on a three-phase motor slot vector star diagram under the condition that the pole slot cooperation of the current motor meets the winding design requirement; based on the adjusted slot vector star graph and a coil pitch determined according to pole slot matching, a winding arrangement mode is designed under the requirement for balancing magnetomotive force amplitude; based on the designed winding arrangement mode, obtaining the current magnitude and phase of different terminals in each phase by introducing current with preset magnitude and phase; and determining the number of turns of each terminal in each phase under the constraint of a principle that magnetomotive force amplitudes generated by each coil are equal based on the current magnitude and the phase of different terminals in each phase. According to the invention, comprehensive suppression of stator magnetomotive force harmonics is realized through pole slot cooperation and six-phase current phase difference optimization in combination with a split-phase belt winding structure design.

Description

Technical Field

[0001] The present invention relates to the technical field of motors, and in particular to a six-phase motor and a hybrid winding design method for suppressing harmonics thereof. Background Art

[0002] In the field of motor design, fractional slot winding technology is widely used in high-precision drive scenarios such as ship propulsion, wind power generation, electric vehicles, and aerospace because it can effectively reduce the cogging torque of permanent magnet motors. However, the fractional slot winding structure used in the prior art has significant defects: the stator magnetomotive force harmonic content is extremely rich. The rotation speed of these harmonics is not synchronized with the motor speed, which will induce high-frequency eddy currents in the rotor conductor, resulting in a sharp increase in rotor losses. Since the rotor is a high-speed rotating component and it is difficult to achieve effective heat dissipation, heat accumulation will cause the degradation of the magnetic properties of the permanent magnet and the aging of the winding insulation, seriously threatening the reliability and life of the motor. In addition, magnetomotive force harmonics of a certain order (such as the 5th and 7th) will excite strong radial electromagnetic forces, aggravating the vibration and noise of the motor, especially when running at high speeds. This problem is particularly prominent, which greatly limits the application of fractional slot windings in high-performance motors.

[0003] Most of the existing solutions are to suppress harmonics by changing the number of motor slots or introducing flux barriers in the stator yoke, but these methods are complex and costly, and may not be able to take into account the comprehensive suppression of high and low harmonics. Therefore, there is an urgent need for an efficient design method that can achieve full-band harmonic suppression and reduce losses and noise by optimizing the winding connection method without changing the main structure of the motor, so as to break through the limitations of the existing technology. Summary of the invention

[0004] In order to solve the above problems without changing the existing dual three-phase motor structure, the present invention proposes a hybrid winding design method for six-phase motor harmonic suppression, comprising the steps of: S1: When the pole-slot coordination of the current motor meets the winding design requirements, the slot vector star diagram is obtained under the optimization of the six-phase current phase difference based on the slot vector star diagram of the three-phase motor; S2: Based on the adjusted slot vector star diagram and the coil pitch determined according to the pole-slot matching, the winding arrangement is designed under the requirement of balanced magnetomotive force amplitude; S3: Based on the designed winding arrangement, the current magnitude and phase of different terminals in each phase are obtained by passing a current of preset magnitude and phase; S4: Based on the current magnitude and phase of different terminals in each phase, the number of turns of each terminal in the phase is determined under the constraint that the amplitude of the magnetomotive force generated by each coil is equal.

[0005] In the present invention, through innovative pole-slot matching and six-phase current phase difference optimization, combined with split-phase belt winding structure design, the stator magnetomotive force harmonics are fully suppressed. At the same time, there is no need to change the stator or rotor structural parameters, and performance can be improved only by optimizing the winding connection method. It is compatible with existing motor production processes and is particularly suitable for high-speed and high-power density scenarios. It reduces costs while expanding the application range of fractional slot windings.

[0006] Furthermore, in the step S1, the winding design requires that the number of slots Z of the motor stator satisfies Z=18k, k is a positive integer, the number of pole pairs of the motor rotor is P, and Z and P are mutually prime.

[0007] Furthermore, in the step S1, the six-phase current phase difference optimization is specifically as follows: For the first phase, the second phase and the third phase on the same layer of the coil, a first power input terminal and a second power input terminal are respectively provided; The input currents of the first power input terminals of each phase differ by 120° electrical angle in sequence; The second power input terminal of each phase has a phase difference of 40°, 160° and 280° in electrical angle with respect to the first power input terminal of the first phase.

[0008] Furthermore, in the step S2, the winding arrangement is specifically as follows: Based on the slot vector star diagram, the 60° phase band of the original three-phase motor is divided into three 20° sub-phase bands, and correspondingly allocated to the first sub-winding segment, the second sub-winding segment and the third sub-winding segment; In the same phase belt, the first sub-winding section is connected in parallel with the second sub-winding section and then connected in series with the third sub-winding section; In the same phase belt, the parallel connection ends of the first sub-winding segment and the second sub-winding segment are connected to the six-phase power input port; the non-series ends of the third sub-winding segment of each phase belt are closed through a neutral point connection.

[0009] Furthermore, the first sub-winding segment serves as a first power input terminal, and the second sub-winding segment serves as a second power input terminal.

[0010] Furthermore, in step S3, the current magnitudes and phases of different terminals in each phase are specifically as follows: The input current amplitudes of the first and second sub-winding sections of each phase band are equal, and the current amplitude of the third sub-winding section is derived from Kirchhoff's current law as the input current amplitude. times, and the phase lags by 20° relative to the first winding section of the in-phase belt.

[0011] Furthermore, in the step S4, the number of turns of each terminal in the phase is specifically determined under the following constraints: The number of turns NC of the first sub-winding segment, the number of turns NC of the second sub-winding segment, and the number of turns N1 of the third sub-winding segment satisfy the relationship: , and the ratio of winding turns is verified by the principle of magnetomotive force amplitude balance.

[0012] Furthermore, in the step S4, the magnetomotive force amplitude balance principle is specifically: under the current number of winding turns, the total magnetic winding magnetomotive force tends to zero, and the total magnetic winding magnetomotive force is calculated by the following formula: In the formula, is the total winding magnetomotive force, is the harmonic order, and its value range is , is an integer, when hour The sign is positive, when hour The sign is negative, is the coefficient related to the amplitude, for Subharmonic stator magnetomotive force amplitude, is the current amplitude, They are the second sub-winding segment and the third sub-winding segment in the M phase belt respectively. is the spatial phase shift angle corresponding to the magnetomotive force of the second sub-winding segment and the first sub-winding segment in the M-phase band, is the phase difference of the input current between the first sub-winding segment and the second sub-winding segment in the M-phase band, is the spatial phase shift angle corresponding to the magnetomotive force of the third sub-winding segment and the first sub-winding segment in the M phase band, is the phase difference of the input current between the first sub-winding segment and the third sub-winding segment in the M-phase band, is the motor rotor rotation speed, For time, is the spatial position angle, is the three-phase composite magnetomotive force Phase of subharmonics.

[0013] Furthermore, in the step S2, the coil pitch is determined according to the polar moment of the pole slot matching. Select, the polar moment satisfies , and the coil pitch y is the polar moment An integer or fractional multiple of .

[0014] The present invention also includes a six-phase motor, including a stator, a rotor and a six-phase winding, wherein the six-phase motor is designed based on the hybrid winding design method for harmonic suppression of the six-phase motor, wherein: The number of slots Z of the stator satisfies Z=18k, k is a positive integer, the number of pole pairs of the rotor is P, and Z and P are mutually prime; Each phase of the six-phase winding occupies a phase band of 60° electrical angle, and each phase band is equally divided into three sub-phase bands of 20° electrical angle, corresponding to the first sub-winding segment, the second sub-winding segment and the third sub-winding segment respectively; In the same phase belt, the first sub-winding section is connected in parallel with the second sub-winding section and then connected in series with the third sub-winding section; In the same phase belt, the parallel connection end of the first sub-winding segment and the second sub-winding segment is connected to the six-phase power input port; the non-series end of the third sub-winding segment of each phase belt is closed through the neutral point connection; The phase difference between the sub-phase bands of each phase of the six-phase winding is 20° electrical angle, and the sub-winding segments of the same name of adjacent phases are spaced 120° electrical angle apart; In each phase band, the number of turns of the first sub-winding segment and the second sub-winding segment is NC, and the number of turns of the third sub-winding segment N1 satisfies The relationship formula.

[0015] Compared with the prior art, the present invention has at least the following beneficial effects: (1) The hybrid winding design method for six-phase motor harmonic suppression proposed in the present invention realizes comprehensive suppression of stator magnetomotive force harmonics through innovative pole-slot matching and six-phase current phase difference optimization combined with split-phase belt winding structure design; (2) The 60° phase band of the traditional three-phase motor is evenly divided into three 20° sub-phase bands, and the winding coefficient is significantly improved through a mixed connection method of parallel segments and series segments, so that the winding utilization rate can be improved, thereby enhancing the motor efficiency; (3) By setting a specific phase difference of the six-phase input current and combining the ratio of the number of turns, the non-tooth harmonics of a specific order are directionally offset under the principle of magnetomotive force amplitude balance. This design not only reduces the eddy current loss of the permanent magnet, but also greatly weakens the radial electromagnetic force density, reduces the torque pulsation, and improves the average torque, significantly optimizing the smoothness and output capacity of the motor operation. (4) There is no need to change the structural parameters of the stator or rotor. Performance improvement can be achieved simply by optimizing the winding connection method. It is compatible with existing motor production processes and is particularly suitable for high-speed, high-power density scenarios. It reduces costs while expanding the application range of fractional-slot windings. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A step diagram of a hybrid winding design method for harmonic suppression of a six-phase motor; Figure 2 This is the slot vector star diagram of an 18-slot 10-pole motor (comparison object); Figure 3The slot vector star diagram of an 18-slot 10-pole motor (the present invention); Figure 4 This is a schematic diagram of the motor structure of an 18-slot 10-pole motor (comparison object); Figure 5 It is a schematic diagram of the motor structure of an 18-slot 10-pole motor (the present invention); Figure 6 This is a schematic diagram of the winding coil connection of an 18-slot 10-pole motor (comparison object); Figure 7 It is a schematic diagram of the connection of the winding coils of an 18-slot 10-pole motor (the present invention); Figure 8 This is a distribution diagram of the magnetomotive force spectrum of the winding of the 18-slot 10-pole motor comparison object and the embodiment of the present invention; Fig. 9 The finite element analysis data of the torque of the comparative object and the embodiment of the present invention; Fig.10 The finite element analysis data of the eddy current loss of the permanent magnet of the comparative object and the embodiment of the present invention; Fig.11 Finite element analysis data of radial electromagnetic force spectrum of armature of comparison object and embodiment of the present invention. DETAILED DESCRIPTION

[0017] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments. Embodiment 1

[0018] Although the traditional fractional slot winding design performs well in reducing cogging torque, its inherent stator magnetomotive force harmonic problem has always restricted the further development of high-performance motors. Taking a typical 18-slot 10-pole permanent magnet synchronous motor as an example, when using a traditional three-phase 60° phase belt winding, the amplitudes of ν=5, 7, 11, and 13 harmonics in the stator magnetomotive force are significant. These harmonics generate an asynchronous rotating magnetic field in the air gap, causing high-frequency eddy currents to be induced in the rotor permanent magnets and sheaths. The measured eddy current loss is as high as 1336.8mW, causing local temperature rise to exceed the limit and accelerating the demagnetization of the permanent magnets. At the same time, the radial electromagnetic force excited by the harmonics (such as ν=6th order) resonates with the natural frequency of the stator, resulting in vibration and noise levels far exceeding industrial standards.

[0019] To solve the above problems, Figure 1 As shown, the present invention proposes a hybrid winding design method for six-phase motor harmonic suppression, comprising the steps of: S1: When the pole-slot coordination of the current motor meets the winding design requirements, the slot vector star diagram is obtained under the optimization of the six-phase current phase difference based on the slot vector star diagram of the three-phase motor; S2: Based on the adjusted slot vector star diagram and the coil pitch determined according to the pole-slot matching, the winding arrangement is designed under the requirement of balanced magnetomotive force amplitude; S3: Based on the designed winding arrangement, the current magnitude and phase of different terminals in each phase are obtained by passing a current of preset magnitude and phase; S4: Based on the current magnitude and phase of different terminals in each phase, the number of turns of each terminal in the phase is determined under the constraint that the amplitude of the magnetomotive force generated by each coil is equal.

[0020] Specifically, the present invention realizes the optimized design of low-harmonic six-phase hybrid winding through the following technical solutions: First, a motor structure that meets specific pole-slot matching conditions is selected, that is, the number of slots Z=18k (k is a positive integer), and the number of pole pairs P and Z are mutually prime. This design ensures the symmetry of the magnetic field distribution and avoids the harmonic superposition problem caused by the common divisor of the number of slots and the number of poles. On this basis, the six-phase current phase difference optimization reconstruction is performed based on the slot vector star diagram of the traditional three-phase motor.

[0021] First, draw the slot vector star diagram of the original three-phase motor, and the slot distance point angle is , the slot numbers of the slot vector star diagram are allocated clockwise or counterclockwise. The original three-phase motor is arranged according to the 60° phase belt, with a total of 6 phase belts, namely A, B, C and the corresponding negative phase belts -A, -B, -C. Figure 3 As shown (taking an 18-slot 10-pole unit motor as an example), the present invention evenly divides the original 60° phase band into three sub-phase bands (such as A1, A2, and a1 of phase A) that each occupy an electrical angle of 20°. By adjusting the slot number allocation rule, a phase difference of 20° and 40° is formed between adjacent phase bands (for example, A1 and a1 differ by 20°, and A1 and A2 differ by 40°). The total phase band range is still 60°, and the B phase and the C phase use the same division logic to form B1, B2, b1 and C1, C2, c1, a total of 18 slots, thereby providing a phase alignment basis for six-phase current injection.

[0022] Then, according to the slot vector star diagram, combined with the coil pitch determined by the pole slot matching, the double-layer winding layout of the winding is determined (A, B, C is one layer, -A, -B, -C is another layer). The present invention adopts the parallel-series hybrid topology result.

[0023] The sub-phase belts of each phase are connected according to specific rules. Take phase A as an example. Figure 7 As shown, in the same layer, A1 (the upper layer A1 of slot 1 and the lower layer -A1 of slot 10) and A2 (the upper layer A2 of slot 5 and the lower layer -A2 of slot 14) are connected in parallel to form a six-phase input terminal (A1, B1, C1, A2, B2, C2); the parallel branch is connected in series with a1 (the upper layer a1 of slot 12 and the lower layer -a1 of slot 3), and finally closed through the neutral point.

[0024] Furthermore, harmonic cancellation is achieved by configuring the phase difference of the six-phase current. The current amplitudes of the six-phase input terminals are , but the phase is distributed according to a specific rule: the currents of terminals B1, C1, A2, B2, and C2 lag 120°, 240°, 40°, 160°, and 280° electrical angles relative to terminal A1, respectively. Based on Kirchhoff's current law, the current amplitude of the series segment (a1, b1, c1) is derived as , and the phase lags 20° relative to the corresponding parallel segment, thereby ensuring the vector synthesis effect of the magnetomotive force. Finally, according to the principle of equal magnetomotive force amplitude, the number of turns NC of the parallel segment (A1, A2) and the number of turns N1 of the series segment (a1) are set to satisfy The same applies to the remaining B phase and C phase.

[0025] The harmonic elimination condition is verified by synthesizing the total winding magnetomotive force formula, that is, at the current number of winding turns, the total magnetic winding magnetomotive force tends to zero: In the formula, is the total winding magnetomotive force, is the harmonic order, is the coefficient related to the amplitude, for Subharmonic stator magnetomotive force amplitude, is the current amplitude, They are the second sub-winding segment and the third sub-winding segment in the M phase band respectively (they can be A2, a1, or B2, b1, or C2, c1, and the total magnetomotive force of each phase is calculated respectively). is the spatial phase shift angle corresponding to the magnetomotive force of the second sub-winding segment and the first sub-winding segment in the M-phase band, is the phase difference of the input current between the first sub-winding segment and the second sub-winding segment in the M-phase band, is the spatial phase shift angle corresponding to the magnetomotive force of the third sub-winding segment and the first sub-winding segment in the M phase band, is the phase difference of the input current between the first sub-winding segment and the third sub-winding segment in the M-phase band, is the motor rotor rotation speed, For time, is the spatial position angle, The three-phase composite magnetomotive force Phase of subharmonics.

[0026] Through precise turns ratio control, the harmonics generated by each winding section ( order) magnetomotive force cancels each other out, and only the tooth harmonics ( order) and a small part of other order harmonics, achieving comprehensive suppression of high and low order harmonics.

[0027] It is not difficult to see that the present invention achieves comprehensive suppression of high and low-order harmonics without changing the stator or rotor structure through pole-slot matching optimization, six-phase current phase difference configuration and hybrid winding topology design. Its core innovation is to subdivide the traditional phase band into sub-phase bands, and through parallel-series hybrid connection and precise turns control, directionally offset harmful harmonics, providing an efficient and low-cost solution for high-performance permanent magnet motors, especially suitable for high-speed and high-reliability scenarios such as electric vehicle drive and aerospace propulsion.

[0028] Based on this design, the present invention designs a six-phase motor, including a stator, a rotor and a six-phase winding, wherein: The number of slots Z of the stator satisfies Z=18k, k is a positive integer, the number of pole pairs of the rotor is P, and Z and P are mutually prime; Each phase of the six-phase winding occupies a phase band of 60° electrical angle, and each phase band is equally divided into three sub-phase bands of 20° electrical angle, corresponding to the first sub-winding segment, the second sub-winding segment and the third sub-winding segment respectively; In the same phase belt, the first sub-winding section is connected in parallel with the second sub-winding section and then connected in series with the third sub-winding section; In the same phase belt, the parallel connection end of the first sub-winding segment and the second sub-winding segment is connected to the six-phase power input port; the non-series end of the third sub-winding segment of each phase belt is closed through the neutral point connection; The phase difference between the sub-phase bands of each phase of the six-phase winding is 20° electrical angle, and the sub-winding segments of the same name in adjacent phases are separated by 120° electrical angle; In each phase band, the number of turns of the first sub-winding segment and the second sub-winding segment is NC, and the number of turns of the third sub-winding segment N1 satisfies The relationship formula. Embodiment 2

[0029] In order to better understand the technical content of the present invention, this embodiment takes an 18-slot 10-pole unit motor as an example, and realizes full-band harmonic suppression by reconstructing the winding phase band distribution and optimizing the current phase difference while keeping the stator and rotor structures unchanged, and verifies the example using finite element method.

[0030] First, determine the pole-slot coordination of the motor and draw a slot vector star diagram, such as Figure 2 As shown in the figure, the slot vector star diagram obtained is the comparison object (traditional three-phase motor, using star connection). Figure 3 The slot vector star diagram obtained for drawing is the 18-slot 10-pole unit motor of this embodiment.

[0031] Then, the arrangement of the windings is determined. The motor structure schematic diagrams of the comparison object and the object of this embodiment are as follows: Figure 4 and Figure 5 As shown in FIG. 1 , the materials and dimensions of the stator and rotor of the motor are the same, and the main difference between the two is the radial end connection of the winding. For this embodiment, it is an 18-slot structure with double-layer winding, so there are a total of 18 coils. The winding coil connection diagram of the comparative object and the embodiment of the present invention is shown in FIG. Figure 6 and Figure 7 shown.

[0032] The star diagram can be used to know the phase difference of the armature winding in each slot, so Figure 2 and Figure 3 It can be seen that the 18 vectors in the star diagram represent the slot numbers of the upper side (lower side) of the coil in the 18 stator slots of this embodiment, which are evenly distributed within a circle, and the angle between two adjacent vectors is 360° / 18=20°. When the vectors are numbered, the electrical angle between adjacent slots is 20×5=100° (the slot electrical angle calculation formula is: , then when Z is 18 and P is 5, that is 100°), mark each vector with a slot number. Then phase separation is performed according to the rules of A, -C, B, -A, C, -B. It can be seen that each part of A, -C, B, -A, C, -B is divided into 3 vectors, among which part A is divided into A1, A2, a2, and the slot numbers corresponding to its vectors are 1, 12, and 5 respectively. The potential phase difference between A2 and A1 is 40°, and the potential phase difference between a1 and A1 is 20°. The working wave winding coefficient of the comparison object can be calculated to be 0.945 based on the slot vector star diagram. The present invention divides the winding of phase A into three parts, A1, A2, and a1, eliminating the distribution effect of the winding, and its working wave winding coefficient is 0.985. In comparison, the winding coefficient of the motor is increased by 4%, and the higher the winding coefficient, the higher the utilization rate of the standard winding, indicating that the efficiency of the motor is higher.

[0033] Further, based on the winding coil connection diagram, slot 1 constitutes the positive of A1, slot 10 constitutes the negative of A1, slot 5 constitutes the positive of A2, slot 14 constitutes the negative of A2, slot 12 constitutes the positive of a1, and slot 3 constitutes the negative of a1. The current flows in from the two ports A1 and A2, A1 and A2 are connected in parallel and then in series with a1, so the current in the coil of part a1 is determined by the current size and phase in A1 and A2. The connection principle of parts B and C is the same as that of part A.

[0034] Then take phase A as an example. Since the ends of A1 and A2 are connected together and then connected to a1, the currents in phases A1 and A2 have a 40-degree phase shift. According to Kirchhoff's current law, the relationship between the currents in A1, A2 and a1 is: ,in, are the current amplitudes in A1 and A2, is the current in a1. In order to ensure the symmetry of the armature magnetomotive force, the relationship between the number of turns of the windings in different parts must satisfy , where NC is the number of winding turns of parts A1 and A2, and N1 is the number of winding turns of part a1.

[0035] According to the expression of each phase current: (1) in, is the expression of each phase current, is the motor rotor rotation angle, For time, is the initial phase difference of the current, that is, the potential phase difference of the slot potential between A1 and A2 is 40°.

[0036] The winding function equation of each winding is expressed in the form of Fourier series: (2) in, is the winding function equation of each phase winding, for The stator magnetomotive force amplitude of subharmonic motor, is the spatial position angle, is the spatial phase shift angle corresponding to the magnetomotive force of the windings of part A2 and part A1, is the spatial phase shift angle corresponding to the magnetomotive force of the windings of part a1 and part A1, and the same is true for There are four slots between A1 and A2. , there are 11 slots between A1 and a1, , since the slot potential star diagram of the winding is symmetrically distributed, , .

[0037] Then according to the total winding magnetomotive force formula: (3) Among them, F1, F2 and F3 are the stator magnetomotive force of their respective parts of the winding, and F is the total winding magnetomotive force. Substituting formulas (1) and (2) into formula (3), the total winding magnetomotive force equation is finally obtained: (4) in, They are the second sub-winding segment and the third sub-winding segment in the M phase band respectively (they can be A2, a1, or B2, b1, or C2, c1, and the total magnetomotive force of each phase is calculated respectively). is the spatial phase shift angle corresponding to the magnetomotive force of the second sub-winding segment and the first sub-winding segment in the M-phase band, is the phase difference of the input current between the first sub-winding segment and the second sub-winding segment in the M-phase band, is the spatial phase shift angle corresponding to the magnetomotive force of the third sub-winding segment and the first sub-winding segment in the M phase band, is the phase difference of the input current between the first sub-winding segment and the third sub-winding segment in the M-phase band, is a coefficient related to the amplitude (the amplitude is related to the number of coil turns and the number of parallel branches), is the three-phase composite magnetomotive force The phase of the subharmonic. Among them, The value range is , the ± in formula (4) depends on the order of the harmonic. When taking the positive When , it is negative. Otherwise, the situation is just the opposite. When equation (5) holds, the harmonic of this order is eliminated.

[0038] (5) According to formula (5), the harmonic orders that can be eliminated by the hybrid winding design method proposed in the present invention can be determined. For this embodiment, the calculation verifies that the remaining harmonic orders are the tooth harmonic orders of nZ±P, i.e., 13, 23, 31, 41… That is, this embodiment eliminates all harmful harmonic orders other than nZ±P. Therefore, the present invention not only eliminates the low-order harmonics that have a greater impact on the eddy current loss of the permanent magnet, but also eliminates the high-order harmonics that have a greater impact on the vibration noise. The specific harmonic orders eliminated are as follows: Figure 8 shown.

[0039] In addition, this embodiment also performs finite element simulation with a comparative object to further demonstrate the advantages of the present invention. Fig. 9 The finite element analysis data of the torque of the 18-slot 10-pole three-phase motor of the present invention and the traditional one are shown in the figure. Fig.10 The finite element analysis data of the eddy current loss of permanent magnets of the present invention and the traditional 18-slot 10-pole three-phase motor are shown in the figure. Fig.11 The finite element analysis data of the radial electromagnetic force spectrum of the armature of the traditional 18-slot 10-pole three-phase motor of the present invention are provided.

[0040] According to the finite element simulation results, the torque pulsation of the three-phase traditional star connection (Traditional star connection, TSC) is 0.052, and the torque pulsation of the six-phase hybrid connection (Six Phase Hybrid Connection, SPHC) is 0.034, so the torque pulsation is reduced by 34.6%. The average torque of TSC is 4.18Nm, and the average torque of SPHC is 4.27Nm, and the average torque is increased by 2.15%. In terms of permanent magnet eddy current loss, the permanent magnet eddy current loss of SPHC is much lower than that of TSC. They are 1336.8mW and 1209.8mW respectively. SPHC is about 9.5% lower than TSC. Therefore, the present invention improves the average torque, reduces the torque pulsation, and reduces the eddy current loss of the permanent magnet.

[0041] In summary, the hybrid winding design method for six-phase motor harmonic suppression proposed in the present invention achieves comprehensive suppression of stator magnetomotive force harmonics through innovative pole-slot matching and six-phase current phase difference optimization, combined with a split-phase belt winding structure design.

[0042] The 60° phase band of the traditional three-phase motor is evenly divided into three 20° sub-phase bands, and the winding coefficient is significantly improved through a mixed connection method of parallel sections and series sections, which improves the winding utilization rate and thus enhances the motor efficiency.

[0043] By setting a specific phase difference of the six-phase input current and combining it with the ratio of the number of turns, the non-tooth harmonics of a specific order are directionally offset under the principle of magnetomotive force amplitude balance. This design not only reduces the eddy current loss of the permanent magnet, but also greatly weakens the radial electromagnetic force density, thereby reducing torque pulsation and increasing the average torque, significantly optimizing the smoothness of the motor operation and the output capacity.

[0044] There is no need to change the stator or rotor structural parameters. Performance improvement can be achieved simply by optimizing the winding connection method. It is compatible with existing motor production processes and is particularly suitable for high-speed, high-power density scenarios. It reduces costs while expanding the application scope of fractional-slot windings.

[0045] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0046] In addition, in the present invention, descriptions such as "first", "second", "one", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0047] In the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0048] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

Claims

1. A hybrid winding design method for six-phase motor harmonic suppression, characterized in that: Includes steps: S1: When the pole-slot coordination of the current motor meets the winding design requirements, the slot vector star diagram is obtained under the optimization of the six-phase current phase difference based on the slot vector star diagram of the three-phase motor; S2: Based on the adjusted slot vector star diagram and the coil pitch determined according to the pole-slot matching, the winding arrangement is designed under the requirement of balanced magnetomotive force amplitude; S3: Based on the designed winding arrangement, the current magnitude and phase of different terminals in each phase are obtained by passing a current of preset magnitude and phase; S4: Based on the current magnitude and phase of different terminals in each phase, the number of turns of each terminal in the phase is determined under the constraint that the amplitude of the magnetomotive force generated by each coil is equal.

2. A hybrid winding design method for six-phase motor harmonic suppression as claimed in claim 1, characterized in that: In the step S1, the winding design requires that the number of slots Z of the motor stator satisfies Z=18k, k is a positive integer, the number of pole pairs of the motor rotor is P, and Z and P are mutually prime.

3. A hybrid winding design method for harmonic suppression of a six-phase motor as claimed in claim 1, characterized in that: In step S1, the six-phase current phase difference optimization is specifically as follows: For the first phase, the second phase and the third phase on the same layer of the coil, a first power input terminal and a second power input terminal are respectively provided; The input currents of the first power input terminals of each phase differ by 120° electrical angle in sequence; The second power input terminal of each phase has a phase difference of 40°, 160° and 280° in electrical angle with respect to the first power input terminal of the first phase.

4. A hybrid winding design method for six-phase motor harmonic suppression as claimed in claim 3, characterized in that: In the step S2, the winding arrangement is specifically as follows: Based on the slot vector star diagram, the 60° phase band of the original three-phase motor is divided into three 20° sub-phase bands, and correspondingly allocated to the first sub-winding segment, the second sub-winding segment and the third sub-winding segment; In the same phase belt, the first sub-winding section is connected in parallel with the second sub-winding section and then connected in series with the third sub-winding section; In the same phase belt, the parallel connection ends of the first sub-winding segment and the second sub-winding segment are connected to the six-phase power input port; the non-series ends of the third sub-winding segment of each phase belt are closed through a neutral point connection.

5. A hybrid winding design method for six-phase motor harmonic suppression as claimed in claim 4, characterized in that: The first sub-winding section serves as a first power input terminal, and the second sub-winding section serves as a second power input terminal.

6. A hybrid winding design method for six-phase motor harmonic suppression as claimed in claim 4, characterized in that: In step S3, the current magnitudes and phases of different terminals in each phase are specifically as follows: The input current amplitudes of the first and second sub-winding sections of each phase band are equal, and the current amplitude of the third sub-winding section is derived from Kirchhoff's current law as the input current amplitude. times, and the phase lags by 20° relative to the first winding section of the in-phase belt.

7. A hybrid winding design method for six-phase motor harmonic suppression as claimed in claim 6, characterized in that: In the step S4, the number of turns of each terminal in the phase is specifically determined under the following constraints: The number of turns NC of the first sub-winding segment, the number of turns NC of the second sub-winding segment, and the number of turns N1 of the third sub-winding segment satisfy the relationship: , and the ratio of winding turns is verified by the principle of magnetomotive force amplitude balance.

8. A hybrid winding design method for six-phase motor harmonic suppression as claimed in claim 7, characterized in that: The magnetomotive force amplitude balance principle is specifically: under the current number of winding turns, the total magnetic winding magnetomotive force tends to zero, and the total magnetic winding magnetomotive force is calculated by the following formula: In the formula, is the total winding magnetomotive force, is the harmonic order, and its value range is , is an integer, when hour The sign is positive, when hour The sign is negative, is the coefficient related to the amplitude, for Subharmonic stator magnetomotive force amplitude, is the current amplitude, They are the second sub-winding segment and the third sub-winding segment in the M phase belt respectively. is the spatial phase shift angle corresponding to the magnetomotive force of the second sub-winding segment and the first sub-winding segment in the M-phase band, is the phase difference of the input current between the first sub-winding segment and the second sub-winding segment in the M-phase band, is the spatial phase shift angle corresponding to the magnetomotive force of the third sub-winding segment and the first sub-winding segment in the M phase band, is the phase difference of the input current between the first sub-winding segment and the third sub-winding segment in the M-phase band, is the motor rotor rotation speed, For time, is the spatial position angle, is the three-phase composite magnetomotive force Phase of subharmonics.

9. A hybrid winding design method for six-phase motor harmonic suppression as claimed in claim 2, characterized in that: In the step S2, the coil pitch is based on the pole moment of the pole slot matching. Select, the polar moment satisfies , and the coil pitch y is the polar moment An integer or fractional multiple of .

10. A six-phase motor, comprising a stator, a rotor and a six-phase winding, characterized in that: The six-phase motor is designed based on the hybrid winding design method for harmonic suppression of the six-phase motor according to any one of claims 1 to 9, wherein: The number of slots Z of the stator satisfies Z=18k, k is a positive integer, the number of pole pairs of the rotor is P, and Z and P are mutually prime; Each phase of the six-phase winding occupies a phase band of 60° electrical angle, and each phase band is equally divided into three sub-phase bands of 20° electrical angle, corresponding to the first sub-winding segment, the second sub-winding segment and the third sub-winding segment respectively; In the same phase belt, the first sub-winding section is connected in parallel with the second sub-winding section and then connected in series with the third sub-winding section; In the same phase belt, the parallel connection end of the first sub-winding segment and the second sub-winding segment is connected to the six-phase power input port; the non-series end of the third sub-winding segment of each phase belt is closed through the neutral point connection; The phase difference between the sub-phase bands of each phase of the six-phase winding is 20° electrical angle, and the sub-winding segments of the same name of adjacent phases are spaced 120° electrical angle apart; In each phase band, the number of turns of the first sub-winding segment and the second sub-winding segment is NC, and the number of turns of the third sub-winding segment N1 satisfies The relationship formula.

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