A rotor salient pole reluctance modulator optimization method

Abstract

The present invention discloses a rotor salient pole reluctance modulator optimization method, which belongs to the field of magnetic field modulation motors. A rotor salient pole reluctance modulator optimization method divides the motor into three elements: "excitation source-modulator-filter". Before studying the influence of rotor side parameters on motor performance, for the parameters on the non-rotor salient pole reluctance side, based on parameter sensitivity analysis, the key parameters affecting motor performance are quickly determined and optimized; compared with the prior art, the present application uses a parameter sensitivity analysis algorithm to quickly determine and optimize the key parameters affecting motor performance. After optimizing the key parameters, when optimizing the rotor salient pole reluctance structure, the change in motor performance will only be related to the change in parameters in the rotor salient pole structure, so the general optimization law of the rotor salient pole structure can be accurately revealed.

Description

Technical Field

[0001] The invention relates to the field of magnetic field modulation motors, and in particular to a method for optimizing a rotor salient pole reluctance modulator. Background Art

[0002] Compared with traditional motors, rotor salient pole reluctance magnetic field modulation motors have the advantages of high torque output capacity, high reliability, high efficiency and low fault current, and have application potential and value in the fields of wind power generation, electric vehicles, ship power, servo drive, etc. It is precisely because of the asynchronous magnetic field modulation behavior of the rotor salient pole reluctance modulator that an additional effective harmonic component is established in the air gap magnetic field of the salient pole reluctance magnetic field modulation motor, which plays the most important role in the performance of the motor. The existing optimization of the rotor salient pole structure relies on the modeling and simulation of finite element software, so the obtained rotor salient pole shape has no general guiding significance, and it is impossible to further optimize based on the existing slot depth and pole arc coefficient of the rotor salient pole; therefore, a rotor salient pole reluctance modulator optimization method is proposed. Summary of the invention

[0003] In view of the deficiencies in the prior art, the present invention proposes a rotor salient pole reluctance modulator optimization method, storage medium and device.

[0004] The purpose of the present invention can be achieved through the following technical solutions:

[0005] A rotor salient pole reluctance modulator optimization method, comprising:

[0006] Obtain the parameters of the non-rotor salient pole reluctance side of the motor, calculate the sensitivity of the parameters on the non-rotor salient pole reluctance side based on the parameter sensitivity analysis algorithm, and take the parameters with large sensitivity as the key parameters to be optimized;

[0007] The modulation order of the main harmonic components in the air gap magnetic field is determined by modulating the magnetomotive force expression of the rotor salient pole reluctance modulator;

[0008] Under the same modulation order, the magnetic field conversion coefficients of the motor under different rotor salient pole structures are calculated and compared, and the rotor salient pole structure corresponding to the larger magnetic field conversion coefficient is taken as the optimized rotor salient pole structure of the motor;

[0009] After optimizing the key parameters of the non-rotor salient pole reluctance and determining the optimized rotor salient pole structure of the motor, the pole arc coefficient and slot depth of the rotor salient pole are further determined.

[0010] Furthermore, the calculation formula of the parameter sensitivity analysis algorithm is as follows:

[0011]

[0012]

[0013] Among them, S i For x i Sensitivity to the optimization target F(x); Avg(·) represents the average value calculation; x i is the i-th parameter to be optimized, x0 is its initial value; Δx i For x i The change in Δx i =10%x i , 20% x i ; S com is the comprehensive sensitivity; ω T ,ω rip and ω cog is the weight coefficient, which is 0.6, 0.2 and 0.2 respectively in this patent; S i T , S i rip and S i cog For x i Parameter sensitivity values ​​for average torque, torque ripple and cogging torque.

[0014] Furthermore, the expression of the modulated magnetomotive force of the rotor salient pole reluctance modulator is:

[0015]

[0016] Among them, ε RT is the pole arc coefficient of the rotor teeth; p is the number of main pole pairs of the source air gap magnetic field, and the source air gap magnetic field includes the source excitation magnetic field and the source armature magnetic field; φ is the mechanical angle along the circumference in the modulator as the reference coordinate system; ω r is the rotor mechanical speed; N RT is the number of rotor teeth; l is the modulation order of the rotor salient pole reluctance modulator.

[0017] Furthermore, the rotor salient pole structure includes equidistant distribution, positive trapezoidal distribution, inverted trapezoidal distribution and PWM-like distribution.

[0018] Furthermore, the formula of the equidistantly distributed magnetic field conversion coefficient is:

[0019]

[0020] Among them, ε RT is the pole arc coefficient of the rotor teeth; C p is the fundamental wave magnetic field conversion coefficient; C sum To meet the harmonic magnetic field conversion coefficient of the modulation; C dif To meet the harmonic magnetic field conversion coefficient of differential modulation.

[0021] Furthermore, the formula of the magnetic field conversion coefficient of the positive trapezoidal distribution is:

[0022]

[0023] Among them, ε out is the outer pole arc coefficient of the rotor tooth; ε in is the inner pole arc coefficient of the rotor tooth.

[0024] Furthermore, the formula of the magnetic field conversion coefficient of the inverted trapezoidal distribution is:

[0025]

[0026] Furthermore, the formula of the magnetic field conversion coefficient of the PWM-like distribution is:

[0027]

[0028]

[0029] Among them, ε RT1 is the pole arc coefficient of the main rotor teeth; ε RT2 is the pole arc coefficient of the auxiliary rotor teeth.

[0030] Beneficial effects of the present invention:

[0031] The present invention uses a parameter sensitivity analysis algorithm to quickly determine and optimize key parameters that affect motor performance. After optimizing the key parameters, when optimizing the rotor salient pole reluctance structure, the change in motor performance will only be related to the change in parameters in the rotor salient pole structure, so the general optimization law of the rotor salient pole structure can be accurately revealed. The present invention takes into account the influence of the motor and / or differential modulation pole pair matching on the optimization of the rotor salient pole structure, and explains that the optimization of the motor rotor salient pole structure is independent of the pole pair matching.

[0032] The present invention takes into account the influence of modulation orders under different rotor salient pole structures, and divides the conditions for generating harmonic magnetic flux density in the motor air gap magnetic field due to the modulation of the rotor salient pole reluctance structure into fundamental modulation (l=0), first-order modulation (l=1), second-order modulation (l=2), etc., and determines the optimization direction of the rotor salient pole structure based on the comparison of the magnetic field conversion coefficients under the same modulation order; the present invention can optimize the pole arc coefficient and slot depth of the rotor salient pole structure, and the pole arc coefficient and slot depth of the same type of motors under different pole pair numbers meet the general optimization rules. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The present invention will be further described below in conjunction with the accompanying drawings.

[0034] Figure 1 It is a proposed optimization method of rotor salient pole reluctance modulator based on magnetic field modulation theory;

[0035] Figure 2 A diagram of a 12 / 14 pole magnetic gear compound motor to be optimized in one embodiment;

[0036] Figure 3 A motor diagram for classifying parameters according to the three elements of "excitation source - modulator - filter" in one embodiment;

[0037] Figure 4 A magnetic flux density amplitude decomposition diagram of the main harmonic components of the motor modulated air gap magnetic field in one embodiment;

[0038] Figure 5 is a structural diagram of equidistant rotor salient poles used in one embodiment;

[0039] Figure 6 A diagram showing a positive trapezoidal rotor salient pole structure used in one embodiment;

[0040] Figure 7 A diagram showing the structure of an inverted trapezoidal rotor salient pole used in one embodiment;

[0041] Figure 8 A diagram of a PWM-like distributed rotor salient pole structure used in one embodiment;

[0042] Fig. 9 is a comparison diagram of magnetic field conversion coefficients of four rotor salient pole structures at l=0 in one embodiment;

[0043] Fig.10 is a comparison diagram of magnetic field conversion coefficients of four rotor salient pole structures at l=1 in one embodiment;

[0044] Fig.11 It is a diagram of the optimal rotor salient pole structure of a magnetic gear compound motor proposed in one embodiment;

[0045] Fig.12 A diagram of an optimized 12 / 14 pole magnetic gear compound motor based on the method proposed in the present invention in one embodiment;

[0046] Fig.13 The diagram of the optimized 12 / 10 pole magnetic gear compound motor based on the method proposed by the present invention;

[0047] Fig.14 The diagram of the optimized 12 / 16 pole magnetic gear compound motor based on the method proposed by the present invention;

[0048] Fig.15 This is a comparison chart of the torque external characteristics of the 12 / 14 pole magnetic gear compound motor;

[0049] Fig.16 This is a comparison chart of the torque external characteristics of the 12 / 10 pole magnetic gear compound motor;

[0050] Fig.17 This is a comparison chart of the torque external characteristics of the 12 / 16 pole magnetic gear compound motor. DETAILED DESCRIPTION

[0051] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0052] In the description of the present invention, it should be understood that the terms "opening", "upper", "lower", "thickness", "top", "middle", "length", "inside", "all around" and the like indicating orientation or positional relationship are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the components or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0053] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0054] The present invention proposes a rotor salient pole reluctance modulator optimization method based on magnetic field modulation theory. Figure 1 As shown, Figure 2 Taking the optimization of the 12 / 14 pole initial magnetic gear compound motor shown as an example, the steps are as follows:

[0055] Step 1: Divide the motor into three elements: excitation source - modulator - filter. Before studying the influence of rotor side parameters on motor performance, for the parameters on the non-rotor side, based on parameter sensitivity analysis, quickly determine and optimize the key parameters that affect motor performance:

[0056] The magnetic gear compound motor to be optimized is divided into three elements: "excitation source-modulator-filter", such as Figure 3 As shown in Figure 2, it can be seen that the rotor salient pole structure belonging to the "modulator" element includes the outer pole arc coefficient ε out 、Inner polar arc coefficient ε in and slot depth s depThere are three parameters in total, and the remaining parameters are included in the three elements. The parameters on the non-rotor salient pole reluctance side are selected from them to perform parameter sensitivity analysis. The calculation formula of the parameter sensitivity analysis algorithm is:

[0057]

[0058] Where S i For x i Sensitivity to the optimization target F(x), which in this embodiment selects the average torque, torque ripple and cogging torque of the motor; Avg(·) represents the average value calculation; x i is the i-th parameter to be optimized, x0 is its initial value; Δx i For x i The change in Δx i =10%x i , 20% x i . To illustrate the parameter x i The sensitivity of the overall optimization target of the motor is calculated by the formula:

[0059]

[0060] Among them, ω T ,ω rip and ω cog are weight coefficients, which are respectively 0.6, 0.2 and 0.2 in the present invention; S i T , S i rip and S i cog For x i The parameter sensitivity values ​​of the average torque, torque ripple and cogging torque are shown in Table 1. It can be seen that the stator yoke thickness S yd The comprehensive sensitivity value of is large, indicating that this is a key parameter affecting the motor performance, and its change will have a great impact on the motor performance. Therefore, we choose to optimize S yd , so as to quickly determine and optimize the key parameters that affect the motor performance. After optimizing the key parameters, when considering the optimization of the rotor salient pole reluctance structure, the change in motor performance will only be related to the change in the parameters in the rotor salient pole structure, so the general optimization law of the rotor salient pole structure can be revealed.

[0061] Table 1 Parameter sensitivity analysis of 12 / 14 pole magnetic gear compound motor

[0062]

[0063]

[0064] Step 2: Based on the magnetic field modulation theory, analyze the harmonic components of the main pole pairs in the motor modulated air gap magnetic field and the corresponding modulation order of the rotor salient pole reluctance modulator, and consider the influence of the motor sum / difference modulation pole pair matching on the optimization direction of the rotor salient pole structure:

[0065] The source air gap magnetomotive force component is: f(φ,t)=Fcos(pφ)

[0066] Wherein, p is the number of main pole pairs of the source air gap magnetic field, and the source air gap magnetic field includes the source excitation magnetic field and the source armature magnetic field; F is the amplitude of the source air gap magnetomotive force; φ is the mechanical angle along the circumference in the reference coordinate system of the modulator.

[0067] Based on the magnetic field modulation theory, the modulation order of the main harmonic components in the modulated air gap magnetic field is determined by the rotor salient pole reluctance modulator modulating the magnetomotive force expression. The formula is:

[0068]

[0069] Among them, ω r is the rotor mechanical speed; N RT is the number of rotor teeth; l is the modulation order of the rotor salient pole reluctance modulator, which is a non-negative integer.

[0070] When the number of main pole pairs of the source excitation magnetic field is less than the number of rotor teeth, the motor is said to meet the sum modulation coordination; when the number of main pole pairs of the source excitation magnetic field is greater than the number of rotor teeth, the motor is said to meet the difference modulation coordination. Since the magnetic field conversion coefficient is the same under the same modulation order, the optimization of the motor rotor salient pole reluctance structure has nothing to do with the sum / difference modulation pole pair coordination.

[0071] according to Figure 4 The harmonic flux density of the modulated air gap magnetic field of the 12 / 14 pole magnetic gear compound motor in the figure is decomposed. From the main harmonic components of the modulated excitation magnetic field and the modulated armature magnetic field, the modulation order l of the rotor salient pole reluctance in the motor is determined to be 0 and 1. Therefore, for this motor, the performance comparison of different rotor structures is carried out under these two modulation orders.

[0072] Step 3: According to the modulation order of the rotor salient pole reluctance modulator, determine the optimization direction of the rotor salient pole structure and obtain the theoretical combined optimal structure:

[0073] According to the modulation order of the rotor salient pole reluctance modulator, compare Figure 5 , 6 , 7, and 8 show the magnitude of the magnetic field conversion coefficients of the four rotor salient pole structures. Figure 5 The formula for the equidistantly distributed magnetic field conversion coefficient is:

[0074]

[0075] Among them, ε RT is the pole arc coefficient of the rotor teeth; C p is the fundamental wave magnetic field conversion coefficient; C sum To meet the harmonic magnetic field conversion coefficient of the modulation; C dif To meet the harmonic magnetic field conversion coefficient of differential modulation.

[0076] Figure 6 The formula for the magnetic field conversion coefficient of the positive trapezoidal distribution shown is:

[0077]

[0078] Among them, ε out is the outer pole arc coefficient of the rotor tooth; ε in is the inner pole arc coefficient of the rotor tooth.

[0079] Figure 7 The formula for the magnetic field conversion coefficient of the inverted trapezoidal distribution shown is:

[0080]

[0081] Figure 8 The formula for the magnetic field conversion coefficient of the PWM-like distribution shown is:

[0082]

[0083]

[0084] Among them, ε RT1 is the pole arc coefficient of the main rotor teeth; ε RT2 is the pole arc coefficient of the auxiliary rotor teeth.

[0085] The magnetic field conversion coefficients of the four rotor salient pole structures are compared when the modulation order l is 0 and 1 respectively. Fig. 9 and Fig.10 As shown. For l=0, the magnetic field conversion coefficients of these four rotor salient pole structures change in the same law. As the pole arc coefficient increases, the magnitude of the magnetic field conversion coefficient increases, and the positive trapezoidal distribution and the inverted trapezoidal distribution are more conducive to improving the magnitude of l=0 than the equidistant distribution; for l=l, the magnetic field conversion coefficients of the equidistant distribution, the positive trapezoidal distribution, the inverted trapezoidal distribution and the quasi-PWM distribution decrease as the pole arc coefficient increases. The pole arc coefficients of the first three topologies are basically unchanged when the pole arc coefficient range is [0.4, 0.7], and the coefficient of the quasi-PWM distribution is smaller than the coefficients of the positive trapezoidal distribution and the inverted trapezoidal distribution. Therefore, compared with the equidistant distribution of the initial structure, the positive trapezoidal distribution and the inverted trapezoidal distribution can improve the performance of the magnetic gear motor without affecting the magnitude of l=1 while increasing l=0. The optimal rotor salient pole structure is a combination of the positive trapezoidal distribution and the inverted trapezoidal distribution, as shown in Fig.11 shown.

[0086] Step 4: Analyze the optimization results of motors with different pole pairs, and conduct comparative analysis to obtain a general optimization rule that takes into account the changes in the pole arc coefficient and slot depth in the rotor salient pole structure. The optimization process of other motors can be obtained in the same way.

[0087] According to the above implementation steps, the rotor salient poles of three types of magnetic gear compound motors with 12 / 10, 12 / 14 and 12 / 16 poles are optimized, and the optimization performance indicators are cogging torque, average torque and torque ripple. First, the optimal rotor salient pole structure of the 12 / 14 pole magnetic gear compound motor is a combination of positive trapezoidal distribution and inverted trapezoidal distribution, such as Fig.12 As shown in the figure, its pole arc coefficient and slot depth satisfy the general optimization law; using the method proposed in the present invention, it can be obtained that the salient pole reluctance of the rotor of the magnetic gear composite motor with other pole pairs also satisfies the same optimization law. Fig.13 The 12 / 10 pole magnetic gear compound motor shown and Fig.14 Taking the 12 / 16 pole magnetic gear compound motor shown in the figure as an example, the optimized rotor salient pole structure of these two motors is also a combination of positive trapezoidal distribution and inverted trapezoidal distribution. The optimization results of the three motors are shown in Table 2. The torque external characteristics are compared. Figure 15-17 As shown, when the slot depth meets (s dep1 / s dep )≤0.5, rotor salient pole outer pole arc coefficient ε out is the rotor salient pole inner arc coefficient ε in When the motor is 141%-168% of the torque, the motor can reduce the cogging torque and torque pulsation while increasing the average torque to achieve the optimal torque characteristic. This shows that the rotor salient pole reluctance modulator optimization method proposed in the present invention meets the general optimization law and is independent of the pole pair number matching. The optimization process of other motors can be obtained in the same way.

[0088] Table 2 Optimization results of magnetic gear compound motor

[0089]

[0090] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. A rotor salient pole reluctance modulator optimization method, characterized in that: include: Obtain the parameters of the non-rotor salient pole reluctance side of the motor, calculate the sensitivity of the parameters on the non-rotor salient pole reluctance side based on the parameter sensitivity analysis algorithm, and take the parameters with large sensitivity as the key parameters to be optimized; The modulation order of the main harmonic components in the air gap magnetic field is determined by modulating the magnetomotive force expression of the rotor salient pole reluctance modulator; Under the same modulation order, the magnetic field conversion coefficients of the motor under different rotor salient pole structures are calculated and compared, and the rotor salient pole structure corresponding to the larger magnetic field conversion coefficient is taken as the optimized rotor salient pole structure of the motor; After optimizing the key parameters of the non-rotor salient pole reluctance and determining the optimized rotor salient pole structure of the motor, the pole arc coefficient and slot depth of the rotor salient pole are further determined; The calculation formula of the parameter sensitivity analysis algorithm is as follows: Among them, S i For x i Sensitivity to the optimization target F(x); Avg(·) represents the average value calculation; x i is the i-th parameter to be optimized, and x0 is its initial value; Δx i For x i The change in Δx i =10%x i , 20% x i ; S com is the comprehensive sensitivity; ω T ,ω rip and ω cog is the weight coefficient, which is 0.6, 0.2 and 0.2 respectively; S i T , S i rip and S i cog For x i Parameter sensitivity values ​​for average torque, torque ripple and cogging torque.

2. The rotor salient pole reluctance modulator optimization method according to claim 1, characterized in that: The expression of the modulated magnetomotive force of the rotor salient pole reluctance modulator is: Among them, ε RT is the pole arc coefficient of the rotor teeth; p is the number of main pole pairs of the source air gap magnetic field, and the source air gap magnetic field includes the source excitation magnetic field and the source armature magnetic field; φ is the mechanical angle along the circumference in the modulator as the reference coordinate system; ω r is the rotor mechanical speed; N RT is the number of rotor teeth; l is the modulation order of the rotor salient pole reluctance modulator.

3. The rotor salient pole reluctance modulator optimization method according to claim 1, characterized in that: The rotor salient pole structures include equidistant distribution, positive trapezoidal distribution, inverted trapezoidal distribution and quasi-PWM distribution.

4. The rotor salient pole reluctance modulator optimization method according to claim 3, characterized in that: The formula of the equidistantly distributed magnetic field conversion coefficient is: Among them, ε RT is the pole arc coefficient of the rotor teeth; C p is the fundamental wave magnetic field conversion coefficient; C sum To meet the harmonic magnetic field conversion coefficient of the modulation; C dif To meet the harmonic magnetic field conversion coefficient of differential modulation.

5. The rotor salient pole reluctance modulator optimization method according to claim 3, characterized in that: The formula of the magnetic field conversion coefficient of the positive trapezoidal distribution is: Among them, ε out is the outer pole arc coefficient of the rotor tooth; ε in is the inner pole arc coefficient of the rotor tooth.

6. The rotor salient pole reluctance modulator optimization method according to claim 3, characterized in that: The formula of the magnetic field conversion coefficient of the inverted trapezoidal distribution is:

7. The rotor salient pole reluctance modulator optimization method according to claim 3, characterized in that: The formula of the magnetic field conversion coefficient of the PWM-like distribution is: Among them, ε RT1 is the pole arc coefficient of the main rotor teeth; ε RT2 is the pole arc coefficient of the auxiliary rotor teeth.

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