A six-phase motor and its hybrid winding design method for harmonic suppression

Abstract

The present invention discloses a six-phase motor and a hybrid winding design method for harmonic suppression thereof, relating to the field of motor technology. The method comprises the following steps: obtaining a slot vector star diagram under six-phase current phase difference optimization based on a three-phase motor slot vector star diagram, when the current motor pole-slot matching meets the winding design requirements; designing a winding arrangement under the requirement of balanced magnetomotive force amplitude based on the adjusted slot vector star diagram and the coil pitch determined according to the pole-slot matching; obtaining the current magnitude and phase of different terminals in each phase by passing current of preset magnitude and phase based on the designed winding arrangement; and determining the number of turns of each terminal in each phase under the constraint of the principle of equal magnetomotive force amplitude generated by each coil based on the current magnitude and phase of different terminals in each phase. The present invention achieves comprehensive suppression of stator magnetomotive force harmonics by optimizing the pole-slot matching and six-phase current phase difference, combined with the design of a phase-splitting winding structure.

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 applications such as ship propulsion, wind power generation, electric vehicles, and aerospace due to its ability to effectively reduce cogging torque in permanent magnet motors. However, the fractional-slot winding structure used in existing technologies has a significant drawback: the stator magnetomotive force harmonics are extremely abundant. The rotational speed of these harmonics is asynchronous with the motor speed, inducing high-frequency eddy currents in the rotor conductors, leading to a sharp increase in rotor losses. Since the rotor, as a high-speed rotating component, is difficult to dissipate heat effectively, heat accumulation will cause magnetic degradation of the permanent magnets and aging of the winding insulation, seriously threatening the reliability and life of the motor. In addition, certain magnetomotive force harmonics (such as the 5th and 7th) can induce strong radial electromagnetic forces, exacerbating motor vibration and noise. This problem is particularly prominent at high-speed operation, significantly limiting the application of fractional-slot windings in high-performance motors.

[0003] Existing solutions mostly address harmonic suppression by changing the number of motor slots or introducing flux barriers in the stator yoke. However, these methods are complex and costly, and may not fully suppress both high- and low-order harmonics. Therefore, an efficient design approach is urgently needed to overcome the limitations of existing technologies by optimizing winding connections to achieve full-band harmonic suppression, reduce losses, and reduce noise, without changing the motor's main structure. 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, including the following steps:

[0005] S1: When the pole-slot coordination of the current motor meets the winding design requirements, the slot vector star diagram is obtained based on the slot vector star diagram of the three-phase motor under the optimization of the six-phase current phase difference;

[0006] S2: Based on the adjusted slot vector star diagram and the coil pitch determined by the pole-slot match, the winding arrangement is designed under the requirement of balanced magnetomotive force amplitude;

[0007] 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;

[0008] 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.

[0009] This invention achieves comprehensive suppression of stator magnetomotive force harmonics through innovative pole-slot coordination and optimized six-phase current phase difference, combined with a split-slot winding structure. Furthermore, performance is improved simply by optimizing the winding connection method, without changing stator or rotor structural parameters. This design is compatible with existing motor production processes and is particularly suitable for high-speed, high-power density applications. It reduces costs while expanding the application range of fractional-slot windings.

[0010] Furthermore, in step S1, the winding design requirement is 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.

[0011] Furthermore, in step S1, the six-phase current phase difference optimization is specifically as follows:

[0012] 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;

[0013] The input currents of the first power input terminals of the respective phases differ by 120° electrical angle.

[0014] The second power input terminal of each phase has a phase difference of 40°, 160° and 280° in electrical angle relative to the first power input terminal of the first phase.

[0015] Furthermore, in step S2, the winding arrangement is specifically as follows:

[0016] 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 respectively allocated to the first sub-winding segment, the second sub-winding segment, and the third sub-winding segment;

[0017] In the same phase belt, the first sub-winding segment is connected in parallel with the second sub-winding segment and then connected in series with the third sub-winding segment;

[0018] 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 the neutral point connection.

[0019] 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.

[0020] Furthermore, in step S3, the current magnitudes and phases of different terminals in each phase are specifically as follows:

[0021] The input current amplitudes of the first and second sub-winding segments of each phase are equal, and the current amplitude of the third sub-winding segment 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.

[0022] Furthermore, in the step S4, the number of turns of each terminal in the phase is determined under the following constraints:

[0023] 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 the number of winding turns is verified by the principle of magnetomotive force amplitude balance.

[0024] 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:

[0025]

[0026] Where, 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.

[0027] Furthermore, in the step S2, the coil pitch is determined according to the pole moment of the pole slot. Select, the polar moment satisfies , and the coil pitch y is the polar moment integer or fractional multiples of .

[0028] The present invention also includes a six-phase motor, comprising 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:

[0029] 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;

[0030] 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;

[0031] In the same phase belt, the first sub-winding segment is connected in parallel with the second sub-winding segment and then connected in series with the third sub-winding segment;

[0032] 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;

[0033] 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;

[0034] 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.

[0035] Compared with the prior art, the present invention has at least the following beneficial effects:

[0036] (1) The hybrid winding design method for six-phase motor harmonic suppression proposed in this invention achieves comprehensive suppression of stator magnetomotive force harmonics through innovative pole-slot matching and six-phase current phase difference optimization, combined with the design of a split-phase belt winding structure;

[0037] (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, which improves the winding utilization rate and thus enhances the motor efficiency;

[0038] (3) 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 significantly 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.

[0039] (4) There is no need to change the stator or rotor structural parameters. Performance improvement can be achieved 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. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 A step-by-step diagram of a hybrid winding design method for harmonic suppression in a six-phase motor;

[0041] Figure 2 This is the slot vector star diagram of an 18-slot, 10-pole motor (comparison object);

[0042] Figure 3 The slot vector star diagram of an 18-slot 10-pole motor (the present invention);

[0043] Figure 4 This is a schematic diagram of the motor structure of an 18-slot 10-pole motor (comparison object);

[0044] Figure 5 This is a schematic diagram of the motor structure of an 18-slot 10-pole motor (the present invention);

[0045] Figure 6 This is a schematic diagram of the winding coil connection of an 18-slot 10-pole motor (comparison object);

[0046] Figure 7 This is a schematic diagram of the winding coil connection of an 18-slot 10-pole motor (according to the present invention);

[0047] Figure 8 This is the magnetomotive force spectrum distribution diagram of the winding of the 18-slot 10-pole motor for comparison and the embodiment of the present invention;

[0048] Figure 9 The finite element analysis data of the torque of the comparative object and the embodiment of the present invention;

[0049] Figure 10 Finite element analysis data of eddy current loss of permanent magnets of comparison objects and embodiments of the present invention;

[0050] Figure 11 Finite element analysis data of radial electromagnetic force spectrum of armature of comparison object and embodiment of the present invention. DETAILED DESCRIPTION

[0051] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solutions of the present invention, but the present invention is not limited to these embodiments. Example 1

[0052] While traditional fractional-slot winding designs excel in reducing cogging torque, their inherent stator magnetomotive force harmonics continue to hinder the further development of high-performance motors. For example, in a typical 18-slot, 10-pole permanent magnet synchronous motor using a traditional three-phase, 60° phase-belt winding, the stator magnetomotive force harmonics (ν=5, 7, 11, and 13) are significantly affected. These harmonics generate an asynchronously rotating magnetic field in the air gap, inducing high-frequency eddy currents in the rotor permanent magnets and sheath. Measured eddy current losses reach as high as 1336.8 mW, causing localized temperature rise to exceed the specified limit and accelerating permanent magnet demagnetization. Furthermore, the radial electromagnetic forces (e.g., ν=6) excited by the harmonics resonate with the stator's natural frequency, resulting in vibration and noise levels far exceeding industrial standards.

[0053] 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:

[0054] S1: When the pole-slot coordination of the current motor meets the winding design requirements, the slot vector star diagram is obtained based on the slot vector star diagram of the three-phase motor under the optimization of the six-phase current phase difference;

[0055] S2: Based on the adjusted slot vector star diagram and the coil pitch determined by the pole-slot match, the winding arrangement is designed under the requirement of balanced magnetomotive force amplitude;

[0056] 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;

[0057] 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.

[0058] Specifically, this invention achieves an optimized design for a low-harmonic six-phase hybrid winding through the following technical solutions: First, a motor structure is selected that meets specific pole-slot matching requirements: 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 symmetry in the magnetic field distribution and avoids harmonic superposition caused by the common divisor of the number of slots and poles. Furthermore, a reconstruction is performed using the slot vector star diagram of a traditional three-phase motor with optimized six-phase current phase difference.

[0059] First, draw the slot vector star diagram of the original three-phase motor. The slot distance point angle is , the slot numbers of the slot vector star diagram are assigned in clockwise or counterclockwise order. 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 3As 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, each occupying an electrical angle of 20° (such as A1, A2, and a1 of phase A). By adjusting the slot number allocation rule, a phase difference of 20° and 40° is formed between adjacent phase bands (for example, the difference between A1 and a1 is 20°, and the difference between A1 and A2 is 40°). The total phase band range remains 60°. Phases B and C use the same division logic to form B1, B2, b1 and C1, C2, and c1, for a total of 18 slots, thereby providing a phase alignment basis for six-phase current injection.

[0060] Then, based on the slot vector star diagram and the coil pitch determined by the pole-slot pairing, the double-layer winding layout is determined (A, B, C form one layer, -A, -B, -C form the other layer). This invention uses a parallel-series hybrid topology.

[0061] The sub-phase belts of each phase are connected according to specific rules. Take phase A as an example. Figure 7 As shown, within 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 is finally closed through the neutral point.

[0062] 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 distribution follows a specific rule: the currents at 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 and C phases.

[0063] The harmonic elimination condition is verified by synthesizing the total winding magnetomotive force formula, that is, under the current number of winding turns, the total magnetic winding magnetomotive force tends to zero:

[0064]

[0065] Where, 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, is the three-phase composite magnetomotive force Phase of subharmonics.

[0066] Through precise control of the number of turns ratio, the harmonics generated by each winding section ( order) magnetomotive force cancels each other out, and only the tooth harmonics ( order) and a small number of other orders of harmonics, achieving comprehensive suppression of high and low order harmonics.

[0067] As can be seen, this invention achieves comprehensive suppression of high- and low-order harmonics without changing the stator or rotor structure through optimized pole-slot coordination, six-phase current phase difference configuration, and hybrid winding topology design. Its core innovation lies in subdividing the traditional phase band into sub-phase bands. Through a hybrid parallel-series connection and precise turns control, harmful harmonics are eliminated in a targeted manner. This provides an efficient and low-cost solution for high-performance permanent magnet motors, particularly suitable for high-speed, high-reliability applications such as electric vehicle drives and aerospace propulsion.

[0068] Based on this design, the present invention designs a six-phase motor, including a stator, a rotor and a six-phase winding, wherein:

[0069] 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;

[0070] Each phase of the six-phase winding occupies a 60° electrical angle phase band, and each phase band is equally divided into three 20° electrical angle sub-phase bands, corresponding to the first sub-winding segment, the second sub-winding segment, and the third sub-winding segment respectively;

[0071] In the same phase belt, the first sub-winding segment is connected in parallel with the second sub-winding segment and then connected in series with the third sub-winding segment;

[0072] 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;

[0073] 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;

[0074] 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. Example 2

[0075] 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. By reconstructing the winding phase band distribution and optimizing the current phase difference, full-band harmonic suppression is achieved while keeping the stator and rotor structures unchanged, and the example is verified using finite element analysis.

[0076] 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.

[0077] Then, the arrangement of the windings is determined. The motor structure diagrams of the comparison object and the object of this embodiment are as follows: Figure 4 and Figure 5 As shown, the materials and dimensions of the stator and rotor of the motor are the same. 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.

[0078] The phase difference of the armature winding in each slot can be known through the star diagram, so Figure 2 and Figure 3 As can be seen, the 18 vectors in the star diagram represent the slot numbers of the upper and lower edges of the coils in the 18 stator slots of this embodiment. They are evenly distributed within a circle, and the angle between two adjacent vectors is 360° / 18=20°. When labeling the vectors, the electrical angle between adjacent slots is 20×5=100° (the slot pitch 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, according to the rules of A, -C, B, -A, C, -B, the phases are divided. 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. 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.

[0079] Furthermore, based on the winding coil connection diagram, slot 1 forms the positive terminal of A1, slot 10 forms the negative terminal of A1, slot 5 forms the positive terminal of A2, slot 14 forms the negative terminal of A2, slot 12 forms the positive terminal of a1, and slot 3 forms the negative terminal of a1. Current flows from both A1 and A2, which are connected in parallel and then in series with a1. Therefore, the current in the coil of section a1 is determined by the magnitude and phase of the currents in A1 and A2. The connection principles of sections B and C are the same as those of section A.

[0080] Taking 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 are 40 degrees phase shifted. 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.

[0081] According to the expression of each phase current:

[0082] (1)

[0083] 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°.

[0084] The winding function equation of each winding is expressed in the form of Fourier series:

[0085] (2)

[0086] in, is the winding function equation of each phase winding, for The stator magnetomotive force amplitude of the 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, , .

[0087] Then according to the total winding magnetomotive force formula:

[0088] (3)

[0089] Where F1, F2 and F3 are the stator magnetomotive force of their respective winding parts, 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:

[0090] (4)

[0091] 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. The value range is , ± in formula (4) depends on the order of harmonics, when When taking the positive When , it is negative. Otherwise, the situation is just the opposite. When equation (5) holds, the harmonic of that order is eliminated.

[0092] (5)

[0093] 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, namely 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 vibration noise. The specific harmonic orders eliminated are as follows: Figure 8 shown.

[0094] In addition, this embodiment also performs finite element simulation with a comparative object to further demonstrate the advantages of the present invention. Figure 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 is shown below. Figure 10 The finite element analysis data of the eddy current loss of the permanent magnet of the 18-slot 10-pole three-phase motor of the present invention and the traditional one is shown in the figure. Figure 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 are provided.

[0095] According to the finite element simulation results, the torque ripple of the three-phase traditional star connection (TSC) is 0.052, and the torque ripple of the six-phase hybrid connection (SPHC) is 0.034, so the torque ripple is reduced by 34.6%. The average torque of TSC is 4.18Nm, and the average torque of SPHC is 4.27Nm, with an average torque increase of 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 torque ripple, and reduces permanent magnet eddy current loss.

[0096] 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 the design of a split-phase belt winding structure.

[0097] The 60° phase band of a traditional three-phase motor is evenly divided into three 20° sub-phase bands. Through a mixed connection of parallel and series sections, the winding coefficient is significantly improved, which improves the winding utilization rate and thus enhances the motor efficiency.

[0098] By setting a specific phase difference among the six-phase input currents and combining it with the turns ratio, 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 magnets, but also significantly weakens the radial electromagnetic force density, thereby reducing torque pulsation and increasing the average torque, significantly optimizing the smoothness of the motor's operation and output capacity.

[0099] 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 range of fractional slot windings.

[0100] 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 various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0101] In addition, in the present invention, descriptions such as "first," "second," and "one" are for descriptive purposes only and should not be understood to indicate or imply their relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0102] In the present invention, unless otherwise specified or limited, the terms "connection" and "fixation" should be understood in a broad sense. For example, "fixation" can mean fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will be able to understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0103] 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 this field can implement it. When the combination of technical solutions is mutually 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.

Claims

1. A hybrid winding design method for six-phase motor harmonic suppression, characterized in that: Including steps: S1: When the pole-slot coordination of the current motor meets the winding design requirements, the slot vector star diagram is obtained based on the slot vector star diagram of the three-phase motor under the optimization of the six-phase current phase difference; S2: Based on the adjusted slot vector star diagram and the coil pitch determined by the pole-slot match, 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 each phase is determined under the constraint that the amplitude of the magnetomotive force generated by each coil is equal; In step S1, the winding design requirement is 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; 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 the respective phases differ by 120° electrical angle. The second power input terminal of each phase has a phase difference of 40°, 160° and 280° in electrical angle relative to the first power input terminal of the first phase respectively; In 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 respectively 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 segment is connected in parallel with the second sub-winding segment and then connected in series with the third sub-winding segment; 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; 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 segments of each phase are equal, and the current amplitude of the third sub-winding segment is derived from Kirchhoff's current law as the input current amplitude. times, the phase lags by 20° relative to the first winding section of the in-phase band; In step S4, the number of turns of each terminal in the phase is 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 the number of winding turns is verified by the principle of magnetomotive force amplitude balance; The principle of magnetomotive force amplitude balance is specifically: under the current number of winding turns, the total magnetomotive force of the magnetic winding tends to zero, and the total magnetomotive force of the magnetic winding is calculated by the following formula: Where, 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.

2. A hybrid winding design method for six-phase motor harmonic suppression according to claim 1, characterized in that: 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.

3. A hybrid winding design method for six-phase motor harmonic suppression according to claim 1, characterized in that: In the step S2, the coil pitch is determined by the pole moment of the pole slot. Select, the polar moment satisfies , and the coil pitch y is the polar moment integer or fractional multiples of .

4. A six-phase motor comprising a stator, a rotor and six-phase windings, characterized in that: The six-phase motor is designed based on the hybrid winding design method for six-phase motor harmonic suppression according to any one of claims 1 to 3, 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 segment is connected in parallel with the second sub-winding segment and then connected in series with the third sub-winding segment; 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.

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