Cross coupling calculation method and device based on unequal-width magnetic circuit model

Abstract

The invention discloses a cross coupling calculation method and device based on an unequal-width magnetic circuit model, and the method comprises the steps: adding a permanent magnet equivalent magnetomotive force source into a large-pole magnetic circuit and a small-pole magnetic circuit of a d-axis in a permanent magnet motor through employing a normalization method, and obtaining a normalized large-pole magnetic circuit and a normalized small-pole magnetic circuit, the magnetic circuit model is a d-axis-permanent magnet cross coupling magnetic circuit model based on a normalized large and small pole magnetic circuit method; a magnetic isolation bridge part in the magnetic circuit model is adjusted, a permanent magnet is added, and before the magnetic circuit model is adjusted, a large-pole magnetic circuit triangular area and a small-pole magnetic circuit triangular area are not communicated with the magnetic isolation bridge; in a large and small pole magnetic circuit with permanent magnet magnetomotive force, connecting a triangular area between permanent magnets and a magnetic isolation bridge to obtain a corrected magnetic circuit model after the magnetic isolation bridge channel is corrected; and calculating the total magnetic flux and inductance of the loop by combining the corrected magnetic circuit model and the corresponding equivalent magnetic circuit.

Description

Technical Field

[0001] The present application relates to the field of motor body design, and more specifically, to a cross-coupling calculation method and device based on an unequal-width magnetic circuit model. Background Art

[0002] At present, the numerical calculation methods of permanent magnet motors are relatively mature, including analytical methods and finite element methods. Different from traditional motors, megawatt-class direct-drive wind turbines are characterized by low speed and large capacity, and the electromagnetic load is generally designed to be very high, so the saturation and cross-coupling of the motor cannot be ignored during calculation.

[0003] However, the analytical method usually uses the magnetic permeability saturation coefficient correction, which only considers local saturation and makes it difficult to consider the cross-coupling effect. Although the finite element method has higher accuracy, it is time-consuming and has high requirements on computer hardware. Summary of the invention

[0004] In response to at least one defect or improvement need in the prior art, the present invention provides a cross-coupling calculation method and device based on an unequal-width magnetic circuit model, which solves the problem of low accuracy in existing calculation methods. By further studying the cross-coupling calculation method to adapt to the multi-harmonic and high electromagnetic load characteristics of large-capacity low-speed motors, the accuracy of magnetic field calculation is improved, and it has a high and sufficient engineering application value.

[0005] To achieve the above-mentioned purpose, according to the first aspect of the present invention, a cross-coupling calculation method based on an unequal-width magnetic circuit model is provided, the method comprising: using a normalization method in a permanent magnet motor to add a permanent magnet equivalent magnetomotive force source to the large and small pole magnetic circuits of the d-axis to obtain a normalized large and small pole magnetic circuit model, wherein the magnetic circuit model is a d-axis-permanent magnet cross-coupling magnetic circuit model based on the normalized large and small pole magnetic circuit method; adjusting the magnetic isolation bridge part in the magnetic circuit model to add permanent magnets, wherein the triangular area of ​​the large and small pole magnetic circuits before the adjustment of the magnetic circuit model is not connected to the magnetic isolation bridge; in the large and small pole magnetic circuits with permanent magnet magnetomotive force, a path is connected between the triangular area between the permanent magnets and the magnetic isolation bridge to obtain a corrected magnetic circuit model after the magnetic isolation bridge path is corrected; combining the corrected magnetic circuit model and the corresponding equivalent magnetic circuit to calculate the total magnetic flux and inductance of the circuit.

[0006] In an exemplary embodiment, before the normalization method is used in the permanent magnet motor to add the permanent magnet equivalent magnetomotive force source to the large and small pole magnetic circuits of the d-axis to obtain a normalized large and small pole magnetic circuit model, the method also includes: selecting any side of the magnetic circuit symmetry axis for analysis, and dividing the stator space into large pole space and small pole space in turn according to the size of the positive and negative difference in magnetomotive force, wherein the large pole space contains the maximum positive and negative magnetomotive force in the neighborhood; determining the magnetic circuit space according to the divided large pole space and small pole space, and performing magnetic circuit division of the large and small pole spaces according to the magnetomotive force difference.

[0007] In an exemplary embodiment, the magnetic circuit space is determined according to the divided large pole space and small pole space, and the magnetic circuit division of the large and small pole spaces according to the magnetomotive force difference includes: based on the four magnetic circuit spaces of the electrode, the rotor is allocated to the corresponding magnetic poles according to the proportion of the magnetic circuit space, and a magnetic circuit topology corresponding to the four magnetic circuit spaces is formed, wherein the four magnetic circuit spaces include two large pole spaces and two small pole spaces.

[0008] In an exemplary embodiment, the magnetic isolation bridge portion in the magnetic circuit model is adjusted to add permanent magnets, wherein the large and small pole magnetic circuit triangle area of ​​the magnetic circuit model before adjustment is not connected to the magnetic isolation bridge, including: the added permanent magnet is used as an excitation source of the magnetic circuit, the flux generated by the permanent magnet's magnetomotive force starts from the rotor side, and the permanent magnet's magnetomotive force is greater than the stator's magnetomotive force.

[0009] In an exemplary embodiment, in the large and small pole magnetic circuit with permanent magnet magnetomotive force, a passage is connected between the triangular area between the permanent magnets and the magnetic isolation bridge to obtain a corrected magnetic circuit model after the magnetic isolation bridge passage is corrected, including: a passage is connected between the triangular area between the permanent magnets and the magnetic isolation bridge, and the magnetic flux generated by the permanent magnet participates in the saturation of the magnetic isolation bridge to obtain a corrected magnetic circuit model after the magnetic isolation bridge passage is corrected; the positions of the two large poles in the magnetic circuit model are modified consistently, and the positions of the two small poles are kept consistent with the d-axis small pole magnetic circuit.

[0010] In an exemplary embodiment, the method of calculating the total magnetic flux and inductance of the loop by combining the corrected magnetic circuit model and the corresponding equivalent magnetic circuit includes: rewriting the loop equation group accordingly by combining the corrected magnetic circuit model and the corresponding equivalent magnetic circuit to obtain a rewritten loop equation group; based on the rewritten loop equation group, determining the magnetic flux at each position according to an iterative calculation method, and calculating the total magnetic flux and inductance of the loop.

[0011] According to the second aspect of the present invention, a cross-coupling calculation device based on an unequal-width magnetic circuit model is also provided, which includes: an adding unit, used to use the normalization method to add the permanent magnet equivalent magnetomotive force source to the large and small pole magnetic circuits of the d-axis in the permanent magnet motor, so as to obtain a normalized large and small pole magnetic circuit model, wherein the magnetic circuit model is a d-axis-permanent magnet cross-coupling magnetic circuit model based on the normalized large and small pole magnetic circuit method; an adjusting unit, used to adjust the magnetic isolation bridge part in the magnetic circuit model and add permanent magnets, wherein the triangular area of ​​the large and small pole magnetic circuits before the adjustment of the magnetic circuit model is not connected to the magnetic isolation bridge; a connecting unit, used to connect the triangular area between the permanent magnets and the magnetic isolation bridge in the large and small pole magnetic circuits with permanent magnet magnetomotive force to obtain a modified magnetic circuit model after the magnetic isolation bridge path is corrected; a calculation unit, used to combine the modified magnetic circuit model and the corresponding equivalent magnetic circuit to calculate the total magnetic flux and inductance of the circuit.

[0012] According to a third aspect of the present invention, there is also provided a computer-readable storage medium, in which a computer program is stored, wherein the computer program is configured to execute the above-mentioned cross-coupling calculation method based on the unequal-width magnetic circuit model when running.

[0013] According to a fourth aspect of the present invention, there is also provided an electronic device comprising a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor executes the cross-coupling calculation method based on the unequal width magnetic circuit model through the computer program.

[0014] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects compared with the prior art:

[0015] By using the normalization method in a permanent magnet motor to add the permanent magnet equivalent magnetomotive force source to the large and small pole magnetic circuits of the d-axis, a normalized large and small pole magnetic circuit model is obtained, wherein the magnetic circuit model is a d-axis-permanent magnet cross-coupled magnetic circuit model based on the normalized large and small pole magnetic circuit method; the magnetic isolation bridge part in the magnetic circuit model is adjusted to add permanent magnets, wherein the triangular area of ​​the large and small pole magnetic circuits before the adjustment of the magnetic circuit model is not connected to the magnetic isolation bridge; in the large and small pole magnetic circuits with permanent magnet magnetomotive force, a path is connected between the triangular area between the permanent magnets and the magnetic isolation bridge to obtain a corrected magnetic circuit model after the magnetic isolation bridge path is corrected; combining the corrected magnetic circuit model and the corresponding equivalent magnetic circuit, the total magnetic flux and inductance of the loop are calculated, and the cross-coupling calculation method is further studied to adapt to the multi-harmonic and high electromagnetic load characteristics of large-capacity low-speed motors, thereby improving the accuracy of magnetic field calculation and having high and sufficient engineering application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 A schematic flow chart of an optional cross-coupling calculation method based on an unequal-width magnetic circuit model provided in an embodiment of the present application;

[0018] Figure 2 A schematic diagram of an optional division of the magnetomotive force difference between large and small poles provided in an embodiment of the present application;

[0019] Figure 3 A schematic diagram of an optional d-axis large and small pole magnetic circuit-small pole 1 magnetic circuit model provided in an embodiment of the present application;

[0020] Figure 4A schematic diagram of an optional d-axis large and small pole magnetic circuit-small pole 2 magnetic circuit model provided in an embodiment of the present application;

[0021] Figure 5 A schematic diagram of an optional d-axis large and small pole magnetic circuit - large pole 1 magnetic circuit model provided in an embodiment of the present application;

[0022] Figure 6 A schematic diagram of an optional d-axis large and small pole magnetic circuit - large pole 2 magnetic circuit model provided in an embodiment of the present application;

[0023] Figure 7 An optional large and small pole magnetic circuit model diagram with permanent magnet magnetomotive force provided in an embodiment of the present application - schematic diagram of large pole 2 magnetic circuit model;

[0024] Figure 8 A schematic diagram of a modified magnetic circuit model diagram of an optional magnetic isolation bridge path provided in an embodiment of the present application - a schematic diagram of a large pole 2 magnetic circuit model;

[0025] Fig. 9 A schematic diagram of an optional magnetic circuit iterative calculation process provided in an embodiment of the present application;

[0026] Fig.10 A schematic diagram of a magnetic permeability variation curve of an optional silicon steel sheet provided in an embodiment of the present application;

[0027] Fig.11 A schematic structural diagram of an optional cross-coupling calculation device based on an unequal-width magnetic circuit model provided in an embodiment of the present application;

[0028] Fig.12 A schematic diagram of the structure of an optional electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0030] The terms "first", "second", "third", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices.

[0031] According to one aspect of the embodiments of the present application, a cross-coupling calculation method based on an unequal width magnetic circuit model is provided. Figure 1 The cross-coupling calculation method based on the unequal-width magnetic circuit model provided in the embodiment of the present application is described.

[0032] Figure 1 is a flow chart of an optional cross-coupling calculation method based on an unequal-width magnetic circuit model provided in an embodiment of the present application, such as Figure 1 As shown, the process of the method may include the following steps:

[0033] S102, in the permanent magnet motor, using a normalization method to add a permanent magnet equivalent magnetomotive force source to the large and small pole magnetic circuits of the d-axis to obtain a normalized large and small pole magnetic circuit model, wherein the magnetic circuit model is a d-axis-permanent magnet cross-coupling magnetic circuit model based on the normalized large and small pole magnetic circuit method;

[0034] S104, adjusting the magnetic isolation bridge part in the magnetic circuit model and adding a permanent magnet, wherein the large and small pole magnetic circuit triangle area before the magnetic circuit model is adjusted is not connected to the magnetic isolation bridge;

[0035] S106, in the large and small pole magnetic circuit with permanent magnet magnetomotive force, a path is connected between the triangular area between the permanent magnets and the magnetic isolation bridge to obtain a corrected magnetic circuit model after the magnetic isolation bridge path is corrected;

[0036] S108, combining the modified magnetic circuit model and the corresponding equivalent magnetic circuit, calculating the total magnetic flux and inductance of the loop.

[0037] A cross-coupling calculation method based on an unequal-width magnetic circuit model provided in an embodiment of the present application can be used in numerical calculation scenarios related to permanent magnet motors in motor body design.

[0038] In a permanent magnet motor, the permanent magnet flux and the d-axis flux are interlinked. Based on the proposed unequal width magnetic circuit model, the asymmetric distribution of the d-axis magnetomotive force and the magnetic resistance characteristics in the d-axis magnetic circuit, the d-axis magnetic circuit presents a "large and small pole" distribution. However, the magnetomotive force of the permanent magnet magnetic circuit does not have a "large and small pole" trend, and its magnetic circuit should be divided uniformly according to the permanent magnet pole space. In the definition of magnetic flux lines in electromagnetic field theory, magnetic flux lines must be closed. When dividing the magnetic circuit, the characteristics of magnetic flux lines should be taken into account to make them closed into a complete loop for modeling and calculation. The magnitude of the permanent magnet magnetomotive force is several times that of the stator magnetomotive force. When the fluxes generated by the three different excitation sources of the permanent magnet, the stator d-axis, and the q-axis share the same magnetic resistance, the permanent magnet flux is dominant.

[0039] The embodiment of the present application proposes a cross-coupling calculation method based on an unequal width magnetic circuit model to represent the coupling relationship between the permanent magnet and the d-axis magnetic circuit. Since the permanent magnet and the d-axis magnetic flux have the same direction and there is a strong connection between them, the permanent magnet characteristic position magnetic circuit and the d-axis "large and small pole" magnetic circuit are normalized, that is, the two magnetomotive forces are normalized into one magnetic circuit, and then the same magnetic circuit is used for iterative calculation.

[0040] Exemplarily, in a permanent magnet motor, the normalization method can be used to add the permanent magnet equivalent magnetomotive force source to the "large and small poles" magnetic circuit of the d-axis to obtain a normalized "large and small poles" magnetic circuit model. Afterwards, the magnetic isolation bridge part is adjusted, and the current "large and small poles" magnetic circuit triangle area is not connected to the magnetic isolation bridge. At this time, the flux generated by the newly added permanent magnet magnetomotive force starts from the rotor side, and its magnetomotive force is much larger than the stator magnetomotive force. In this case, the saturation of the magnetic isolation bridge must take its influence into account. Therefore, in the "large and small poles" magnetic circuit with permanent magnet magnetomotive force, it is necessary to connect the triangle area between the permanent magnets and the magnetic isolation bridge to provide a possible magnetic route for the magnetic flux generated by the permanent magnet magnetomotive force, so that the magnetic flux generated by the permanent magnet can participate in the saturation of the magnetic isolation bridge.

[0041] In this embodiment, the two small poles of the motor do not involve permanent magnets in the position of the magnetic circuit, and there is no permanent magnet magnetomotive force, so they are consistent with the d-axis small pole magnetic circuit, and there is no need to add an additional path for the permanent magnet magnetomotive force. Then, according to the revised magnetic circuit model and the corresponding equivalent magnetic circuit, the loop equations can be rewritten accordingly, and the iterative calculation method given at the beginning of this chapter can be used to obtain the magnetic flux at each position, and finally the total loop magnetic flux Φ can be obtained. d and inductor L d =Φ d / I d .

[0042] Through the above steps S102 to S108, the permanent magnet equivalent magnetomotive force source is added to the large and small pole magnetic circuits of the d-axis by the normalization method in the permanent magnet motor to obtain a normalized large and small pole magnetic circuit model, wherein the magnetic circuit model is a d-axis-permanent magnet cross-coupled magnetic circuit model based on the normalized large and small pole magnetic circuit method; the magnetic isolation bridge part in the magnetic circuit model is adjusted to add permanent magnets, wherein the triangular area of ​​the large and small pole magnetic circuits before the adjustment of the magnetic circuit model is not connected to the magnetic isolation bridge; in the large and small pole magnetic circuits with permanent magnet magnetomotive force, a path is connected between the triangular area between the permanent magnets and the magnetic isolation bridge to obtain a corrected magnetic circuit model after the magnetic isolation bridge path is corrected; combining the corrected magnetic circuit model and the corresponding equivalent magnetic circuit, the total magnetic flux and inductance of the loop are calculated, and the cross-coupling calculation method is further studied to adapt to the multi-harmonic and high electromagnetic load characteristics of large-capacity low-speed motors, thereby improving the accuracy of magnetic field calculation and having high and sufficient engineering application value.

[0043] In an exemplary embodiment, before adding the permanent magnet equivalent magnetomotive force source to the large and small pole magnetic circuits of the d-axis by using the normalization method in the permanent magnet motor to obtain the normalized large and small pole magnetic circuit model, the method further includes:

[0044] S11, select any side of the magnetic circuit symmetry axis for analysis, and divide the stator space into a large pole space and a small pole space according to the magnitude of the difference between the positive and negative magnetomotive force, wherein the large pole space contains the maximum positive and negative magnetomotive force in the neighborhood;

[0045] S12, determining the magnetic circuit space according to the divided large pole space and small pole space, and dividing the magnetic circuit of the large and small pole spaces of the magnetomotive force difference.

[0046] In the embodiment of the present application, in the normal working state of the motor, the magnetic resistance of the silicon steel sheet area of ​​the upper part of the rotor magnetic pole, the rotor yoke of the lower part of the rotor, the teeth on the stator side and the silicon steel sheet of the stator yoke are orders of magnitude different from the magnetic resistance of the permanent magnet and the air magnetic barrier area. The d-axis magnetic circuit must pass through two areas with large magnetic resistance. No matter where the direction of the entire path points to, no matter how the magnetic flux path is selected, the main magnetic resistance in the entire circuit must be the permanent magnet area and the air magnetic barrier area. This also leads to the fact that the magnetic circuit distribution of the d-axis will be more affected by the magnetomotive force. The d-axis magnetomotive force is symmetrical, and the axis of symmetry is the axis of the magnetomotive force of the A-phase winding.

[0047] like Figure 2As shown, taking a half unit motor (30 slots and 7 poles) as an example, the stator magnetomotive force should have 7 poles, which are the peaks and valleys of the magnetomotive force waveform. From teeth 16.5 to 12 are large poles (tooth 16 and slot 17, the magnetomotive force is the most negative, because the symmetry axis is on tooth 16, so half of its magnetomotive force is divided to the left of the symmetry axis; tooth 12 and slot 13, the magnetomotive force is the most positive), teeth 11 to 9 are small poles (tooth 9 slot 10 is the one after tooth 8 with the most negative magnetomotive force; tooth 11 slot 12 is the one before tooth 12 with the most positive magnetomotive force), teeth 8 to 3 are large poles (tooth 3 slot 4 is the most positive magnetomotive force; tooth 8 slot 9 is the most negative magnetomotive force), and teeth 2 to 0.5 are small poles.

[0048] Starting from the axis of symmetry (tooth No. 16), considering the symmetry, you can choose any side of the axis of symmetry for analysis. Here we choose the left side. According to the size of the positive and negative difference of the magnetomotive force, the stator space is divided into large pole space and small pole space in turn. The large pole contains the maximum positive and negative values ​​of the magnetomotive force in the neighborhood.

[0049] In an exemplary embodiment, the magnetic circuit space is determined according to the divided large pole space and small pole space, and the magnetic circuit division of the large and small pole spaces of the magnetomotive force difference includes:

[0050] S21, based on the four magnetic circuit spaces of the electrode, the rotor is allocated to corresponding magnetic poles according to the proportion of the magnetic circuit space, forming a magnetic circuit topology corresponding to the four magnetic circuit spaces, wherein the four magnetic circuit spaces include two large pole spaces and two small pole spaces.

[0051] In the present application embodiment, Figure 3-Figure 6 As shown, Figure 3 It is the d-axis "big and small pole" magnetic circuit - small pole 1 magnetic circuit model (9 to 11 teeth on the stator side), Figure 4 It is the d-axis "big and small pole" magnetic circuit-small pole 2 magnetic circuit model (0 to 2 teeth on the stator side), Figure 5 It is the d-axis "big and small pole" magnetic circuit - big pole 1 magnetic circuit model (12 to 16 teeth on the stator side), Figure 6 It is the d-axis "big and small pole" magnetic circuit - big pole 2 magnetic circuit model (3 to 8 teeth on the stator side). Among them, F ds is the stator tooth magnetomotive force, R m , R ad , R ma The magnetic resistance of the permanent magnet or air magnetic barrier is almost the same, R s is the tooth leakage resistance, R e is the stator yoke reluctance, R c is the stator tooth reluctance, R au is the average magnetic resistance of the air magnetic barrier, R g is the air gap reluctance, R b is the magnetic resistance of the magnetic bridge region, R t is the rotor core reluctance, F cis the magnetomotive force of the permanent magnet.

[0052] Optionally, the magnetic circuit space can be determined according to the divided "large and small poles". Taking the motor (30 slots and 7 poles) as an example, there are four types of magnetic circuit spaces, namely large poles 1 and 2 and small poles 1 and 2. The rotor is allocated to the corresponding poles according to the proportion of the magnetic circuit space, forming 4 sets of magnetic circuit topologies corresponding to the 4 "large and small poles". For the two different permanent magnet rotor arrangements of built-in straight line and built-in V-shaped, the topology of the d-axis magnetic circuit model is also the same. The only difference is the magnetic resistance solution at the specific position. It should be noted that Figure 3-Figure 6 The left side of the center adopts a built-in straight-line permanent magnet rotor layout. Figure 3-Figure 6 The middle right part adopts a built-in V-shaped permanent magnet rotor layout.

[0053] In an exemplary embodiment, the magnetic isolation bridge part in the magnetic circuit model is adjusted to add a permanent magnet, wherein the large and small pole magnetic circuit triangle area before the adjustment of the magnetic circuit model is not connected to the magnetic isolation bridge, including:

[0054] S31, the added permanent magnet serves as the excitation source of the magnetic circuit, the flux generated by the permanent magnet magnetomotive force starts from the rotor side, and the permanent magnet magnetomotive force is greater than the stator magnetomotive force.

[0055] In the embodiment of the present application, the d-axis-permanent magnet cross-coupling magnetic circuit model can be based on the normalization-large and small pole magnetic circuit method. There are two main magnetic circuits to choose from using the normalization method. One is to add the permanent magnet equivalent magnetomotive force source to the "large and small pole" magnetic circuit of the d-axis to obtain the following: Figure 7 The normalized "large and small pole" magnetic circuit model shown in the figure, where Figure 7 This is the "big and small pole" magnetic circuit model diagram with permanent magnet magnetomotive force - big pole 2 magnetic circuit model (3 to 8 teeth on the stator side).

[0056] Furthermore, the magnetic isolation bridge can be adjusted, and the current "large and small pole" magnetic circuit triangle area R t1 , R t5 No and magnetic isolation bridge R b1 , R b2 Connected. Since the d-axis "large and small poles" magnetic circuit only analyzes the d-axis magnetomotive force as an excitation source, and does not consider the influence of the rotor permanent magnet, under that calculation condition, the saturation of the magnetic isolation bridge only comes from the magnetic flux generated by the stator winding on the stator side. After adding permanent magnets, the permanent magnets serve as another excitation source in the magnetic circuit, and the magnetic circuit is no longer only excitation of the d-axis stator magnetomotive force. The flux generated by the newly added permanent magnet magnetomotive force starts from the rotor side. At the same time, its magnetomotive force is much larger than that of the stator.

[0057] In an exemplary embodiment, in a magnetic circuit with permanent magnet magnetomotive force, a path is connected between the triangular area between the permanent magnets and the magnetic isolation bridge to obtain a modified magnetic circuit model after the magnetic isolation bridge path is modified, including:

[0058] S41, connecting the triangular area between the permanent magnets and the magnetic isolation bridge to form a path, so that the magnetic flux generated by the permanent magnet participates in the saturation of the magnetic isolation bridge, and obtaining a corrected magnetic circuit model after the magnetic isolation bridge path is corrected;

[0059] S42, the positions of the two large poles in the magnetic circuit model are modified consistently, and the positions of the two small poles are kept consistent with the d-axis small pole magnetic circuit.

[0060] In an exemplary embodiment, combining the modified magnetic circuit model and the corresponding equivalent magnetic circuit, calculating the total magnetic flux and inductance of the loop includes:

[0061] S51, combining the modified magnetic circuit model and the corresponding equivalent magnetic circuit, rewriting the loop equations accordingly to obtain a rewritten loop equations;

[0062] S52, based on rewriting the loop equations, determining the magnetic flux at each position according to an iterative calculation method, and calculating the total magnetic flux and inductance of the loop.

[0063] In the embodiment of the present application, the saturation of the magnetic isolation bridge needs to be considered. Therefore, in the "large and small pole" magnetic circuit with permanent magnet magnetomotive force, it is necessary to connect the triangular area between the permanent magnets and the magnetic isolation bridge to provide a possible magnetic path for the magnetic flux generated by the permanent magnet magnetomotive force, so that the magnetic flux generated by the permanent magnet can participate in the saturation of the magnetic isolation bridge. The corrected magnetic circuit is as follows Figure 8 As shown. Similarly, the same modification is made to the position of the other large pole. Since the positions of the two small poles do not involve permanent magnets, there is no permanent magnet magnetomotive force, so they are consistent with the d-axis small pole magnetic circuit, and there is no need to add an additional path for the permanent magnet magnetomotive force. In addition, the permanent magnet has a tendency to leak magnetic flux through the air magnetic barrier at the end of the permanent magnet. This leakage magnetic path is not drawn in the figure, but it is taken into account in the actual calculation.

[0064] For example, after obtaining the modified magnetic circuit model diagram of the magnetic isolation bridge path - the large pole 2 magnetic circuit model (3 to 8 teeth on the stator side), the loop equations can be rewritten accordingly according to the modified magnetic circuit model and the corresponding equivalent magnetic circuit, and the magnetic flux at each position can be obtained based on the iterative calculation method, and finally the total loop magnetic flux Φ can be obtained. d and inductor L d =Φ d / I d .

[0065] For example, the iterative calculation of the magnetic circuit can be done by Fig. 9 The detailed calculation steps are as follows, taking the q axis as an example:

[0066] Step 1: Set the number of turns N c=8, total current I = 500~1500A, according to the obtained magnetomotive force of each slot under different currents. Taking the characteristic position 5 tooth as an example, the q-axis magnetomotive force of the four slots under pole 1 is given, that is, F qs1 ~F qs4 Before the iterative calculation starts, the flux density of the stator teeth and the air gap can be set to 0.01T.

[0067] Step 2: The cross-sectional area of ​​the corresponding part of the magnetic resistance has been obtained in the magnetic resistance calculation. According to the initial setting of the magnetic flux density, the magnetic flux of stator teeth 1 to 3 and air gaps 1 to 2 can be obtained. Considering the conservation of magnetic flux, the magnetic flux density of stator teeth 4 and conductive parts 1 to 2 of the silicon steel sheet can be further obtained. Based on this, in addition to the air gap magnetic permeability being a constant, the relative magnetic permeability of stator teeth 1 to 4 and conductive parts 1 to 2 of the silicon steel sheet can be obtained according to 10, and then combined with the magnetic resistance calculation method, the magnetic resistance of each part can be obtained.

[0068] Step 3: Substitute the reluctance and leakage reluctance of the stator teeth, stator yoke, air gap, silicon steel sheet into the magnetic circuit equation. Through one calculation, the magnetic flux corresponding to the reluctance of each part is solved. Combined with the reluctance cross-sectional area of ​​the corresponding part known in the reluctance calculation, the new flux density of each part can be calculated. Compare the error with the initially set flux density.

[0069] Step 4: The iterative convergence condition is 0.1%, that is, if the error is greater than 0.1%, replace the magnetic flux density B with (B′-B) / 20+B, and repeat the process of steps 2 and 3. Until the error is less than 0.1%, it is considered that the magnetic permeability and magnetic flux density meet the magnetic flux solved by the magnetic circuit equation. If the computing power allows, the iterative convergence condition can be smaller, and the corresponding solution result is more accurate.

[0070] Step 5: Based on the final solved magnetic flux, the q-axis inductance can be further calculated as L q =1000|φ1+φ2| / I(mH), where φ1 and φ2 are the magnetic fluxes of stator teeth 1 and 2 respectively.

[0071] According to another aspect of the embodiments of the present application, a cross-coupling calculation device for implementing the above-mentioned cross-coupling calculation method based on the unequal-width magnetic circuit model is also provided. Fig.11 is a schematic structural diagram of an optional cross-coupling calculation device based on an unequal-width magnetic circuit model according to an embodiment of the present application, such as Fig.11 As shown, the device may include:

[0072] An adding unit 1102 is used to add a permanent magnet equivalent magnetomotive force source to the large and small pole magnetic circuits of the d-axis in the permanent magnet motor by using a normalization method to obtain a normalized large and small pole magnetic circuit model, wherein the magnetic circuit model is a d-axis-permanent magnet cross-coupling magnetic circuit model based on the normalized large and small pole magnetic circuit method;

[0073] An adjustment unit 1104 is used to adjust the magnetic isolation bridge part in the magnetic circuit model to add a permanent magnet, wherein the large and small pole magnetic circuit triangle area of ​​the magnetic circuit model before adjustment is not connected to the magnetic isolation bridge;

[0074] A connecting unit 1106 is used to connect the triangular area between the permanent magnets and the magnetic isolation bridge in the magnetic circuit with the permanent magnet magnetomotive force to obtain a corrected magnetic circuit model after the magnetic isolation bridge path is corrected;

[0075] The calculation unit 1108 is used to calculate the total magnetic flux and inductance of the loop by combining the modified magnetic circuit model and the corresponding equivalent magnetic circuit.

[0076] It should be noted that the adding unit 1102 in this embodiment can be used to execute the above step S102, the adjusting unit 1104 in this embodiment can be used to execute the above step S104, the connecting unit 1106 in this embodiment can be used to execute the above step S106, and the calculating unit 1108 in this embodiment can be used to execute the above step S108.

[0077] Through the above modules, the normalization method is used in the permanent magnet motor to add the permanent magnet equivalent magnetomotive force source to the large and small pole magnetic circuits of the d-axis to obtain a normalized large and small pole magnetic circuit model, wherein the magnetic circuit model is a d-axis-permanent magnet cross-coupled magnetic circuit model based on the normalized large and small pole magnetic circuit method; the magnetic isolation bridge part in the magnetic circuit model is adjusted to add permanent magnets, wherein the triangular area of ​​the large and small pole magnetic circuits before the adjustment of the magnetic circuit model is not connected to the magnetic isolation bridge; in the large and small pole magnetic circuits with permanent magnet magnetomotive force, a path is connected between the triangular area between the permanent magnets and the magnetic isolation bridge to obtain a corrected magnetic circuit model after the magnetic isolation bridge path is corrected; combining the corrected magnetic circuit model and the corresponding equivalent magnetic circuit, the total magnetic flux and inductance of the circuit are calculated, and the cross-coupling calculation method is further studied to adapt to the multi-harmonic and high electromagnetic load characteristics of large-capacity low-speed motors, thereby improving the accuracy of magnetic field calculation and having high and sufficient engineering application value.

[0078] In an exemplary embodiment, the apparatus further comprises:

[0079] The first division unit is used to select any side of the magnetic circuit symmetry axis for analysis, and divide the stator space into a large pole space and a small pole space in sequence according to the magnitude of the positive and negative difference of the magnetomotive force, wherein the large pole space contains the maximum positive and negative values ​​of the magnetomotive force in the neighborhood;

[0080] The second division unit is used to determine the magnetic circuit space according to the divided large pole space and small pole space, and to divide the magnetic circuit of the large and small pole spaces of the magnetomotive force difference.

[0081] In an exemplary embodiment, the second dividing unit includes:

[0082] The allocation module is used to allocate the rotor to corresponding magnetic poles according to the proportion of the magnetic circuit space based on the four magnetic circuit spaces of the electrode, so as to form a magnetic circuit topology corresponding to the four magnetic circuit spaces, wherein the four magnetic circuit spaces include two large pole spaces and two small pole spaces.

[0083] In an exemplary embodiment, the adjusting unit comprises:

[0084] The excitation source module is used to add the permanent magnet as the excitation source of the magnetic circuit. The flux generated by the magnetomotive force of the permanent magnet starts from the rotor side, and the magnetomotive force of the permanent magnet is greater than the magnetomotive force of the stator.

[0085] In an exemplary embodiment, the connecting unit comprises:

[0086] A connection module is used to connect the triangular area between the permanent magnets and the magnetic isolation bridge to form a path, the magnetic flux generated by the permanent magnet participates in the saturation of the magnetic isolation bridge, and a corrected magnetic circuit model after the magnetic isolation bridge path is corrected is obtained;

[0087] The modification module is used to modify the positions of the two large poles in the magnetic circuit model in a consistent manner, and the positions of the two small poles are consistent with the d-axis small pole magnetic circuit.

[0088] In an exemplary embodiment, the computing unit comprises:

[0089] A rewriting module, used for rewriting the loop equations accordingly by combining the modified magnetic circuit model and the corresponding equivalent magnetic circuit to obtain a rewritten loop equations;

[0090] The calculation module is used to determine the magnetic flux at each position based on the rewritten loop equation group according to an iterative calculation method, and calculate the total magnetic flux and inductance of the loop.

[0091] It should be noted here that the examples and scenarios implemented by the above-mentioned modules and corresponding steps are the same, but are not limited to the contents disclosed in the above-mentioned embodiments. It should be noted that the above-mentioned modules as part of the device can run in a hardware environment and can be implemented by software or hardware, wherein the hardware environment includes a network environment.

[0092] According to another aspect of the embodiments of the present application, a storage medium is further provided. Optionally, in this embodiment, the storage medium can be used to execute the program code of any of the above cross-coupling calculation methods based on unequal-width magnetic circuit models in the embodiments of the present application.

[0093] Optionally, in this embodiment, the storage medium is configured to store program codes for executing the following steps:

[0094] S1, in the permanent magnet motor, a normalization method is used to add the permanent magnet equivalent magnetomotive force source to the large and small pole magnetic circuits of the d-axis to obtain a normalized large and small pole magnetic circuit model, wherein the magnetic circuit model is a d-axis-permanent magnet cross-coupling magnetic circuit model based on the normalized large and small pole magnetic circuit method;

[0095] S2, adjusting the magnetic isolation bridge part in the magnetic circuit model and adding permanent magnets, wherein the large and small pole magnetic circuit triangle area before the adjustment of the magnetic circuit model is not connected to the magnetic isolation bridge;

[0096] S3, in the magnetic circuit with large and small poles of permanent magnet magnetomotive force, a path is connected between the triangular area between the permanent magnets and the magnetic isolation bridge to obtain a modified magnetic circuit model after the magnetic isolation bridge path is modified;

[0097] S4, combining the modified magnetic circuit model and the corresponding equivalent magnetic circuit, calculate the total magnetic flux and inductance of the loop.

[0098] Optionally, the specific examples in this embodiment may refer to the examples described in the above embodiments, which will not be described in detail in this embodiment.

[0099] Among them, computer-readable storage media may include, but are not limited to, any type of disk, including floppy disks, optical disks, DVDs, CD-ROMs, microdrives and magneto-optical disks, ROMs, RAMs, EPROMs, EEPROMs, DRAMs, VRAMs, flash memory devices, magnetic or optical cards, nanosystems (including molecular memory ICs), or any type of medium or device suitable for storing instructions and / or data.

[0100] According to another aspect of the embodiments of the present application, an electronic device for implementing the above-mentioned cross-coupling calculation method based on the unequal-width magnetic circuit model is also provided. The electronic device may be a server, a terminal, or a combination thereof.

[0101] Fig.12 is a schematic diagram of the structure of an optional electronic device according to an embodiment of the present application, such as Fig.12 As shown, it includes a processor 1202, a communication interface 1204, a memory 1206 and a communication bus 1208, wherein the processor 1202, the communication interface 1204, and the memory 1206 communicate with each other through the communication bus 1208, wherein:

[0102] Memory 1206, used for storing computer programs;

[0103] The processor 1202 is used to execute the computer program stored in the memory 1206 to implement the following steps:

[0104] S1, in the permanent magnet motor, a normalization method is used to add the permanent magnet equivalent magnetomotive force source to the large and small pole magnetic circuits of the d-axis to obtain a normalized large and small pole magnetic circuit model, wherein the magnetic circuit model is a d-axis-permanent magnet cross-coupling magnetic circuit model based on the normalized large and small pole magnetic circuit method;

[0105] S2, adjusting the magnetic isolation bridge part in the magnetic circuit model and adding permanent magnets, wherein the large and small pole magnetic circuit triangle area before the adjustment of the magnetic circuit model is not connected to the magnetic isolation bridge;

[0106] S3, in the magnetic circuit with large and small poles of permanent magnet magnetomotive force, a path is connected between the triangular area between the permanent magnets and the magnetic isolation bridge to obtain a modified magnetic circuit model after the magnetic isolation bridge path is modified;

[0107] S4, combining the modified magnetic circuit model and the corresponding equivalent magnetic circuit, calculate the total magnetic flux and inductance of the loop.

[0108] Optionally, the communication bus may be a PCI (Peripheral Component Interconnect) bus, or an EISA (Extended Industry Standard Architecture) bus, etc. The communication bus may be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Fig.12 The communication interface is used for communication between the electronic device and other devices.

[0109] The memory may include RAM, or may include non-volatile memory, such as at least one disk memory. Optionally, the memory may also be at least one storage device located away from the aforementioned processor.

[0110] As an example, the memory 1206 may include, but is not limited to, the adding unit 1102, the adjusting unit 1104, the connecting unit 1106, and the calculating unit 1108 in the cross-coupling calculating device based on the unequal-width magnetic circuit model. In addition, other module units in the cross-coupling calculating device based on the unequal-width magnetic circuit model may also be included but are not limited to, which will not be described in detail in this example.

[0111] The above-mentioned processor can be a general-purpose processor, which can include but not be limited to: CPU (Central Processing Unit), NP (Network Processor), etc.; it can also be DSP (Digital Signal Processing), ASIC (Application Specific Integrated Circuit), FPGA (Field-Programmable Gate Array) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components.

[0112] Optionally, the specific examples in this embodiment may refer to the examples described in the above embodiments, and this embodiment will not be described in detail here.

[0113] It should be noted that, for the aforementioned method embodiments, for the sake of simplicity, they are all expressed as a series of action combinations, but those skilled in the art should be aware that the present application is not limited by the described order of actions, because according to the present application, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present application.

[0114] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0115] In the several embodiments provided in the present application, it should be understood that the disclosed devices can be implemented in other ways. For example, the device embodiments described above are only schematic, such as the division of the units, which is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some service interfaces, and the indirect coupling or communication connection of devices or units can be electrical or other forms.

[0116] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0117] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0118] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable memory. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a memory, including a number of instructions to enable a computer device (which can be a personal computer, server or network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned memory includes: U disk, read-only memory (ROM), random access memory (RAM), mobile hard disk, disk or optical disk and other media that can store program code.

[0119] A person of ordinary skill in the art can understand that all or part of the steps in the various methods of the above embodiments can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable memory, which can include: a flash drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, etc.

[0120] The above is only an exemplary embodiment of the present disclosure, and the scope of the present disclosure cannot be limited thereto. That is, any equivalent changes and modifications made according to the teachings of the present disclosure are still within the scope of the present disclosure. After considering the specification and practicing the disclosure here, those skilled in the art will easily think of the implementation scheme of the present disclosure. This application is intended to cover any modification, use or adaptation of the present disclosure, which follows the general principles of the present disclosure and includes common knowledge or customary technical means in the technical field not recorded in the present disclosure. The description and examples are regarded as exemplary only, and the scope and spirit of the present disclosure are defined by the claims.

[0121] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0122] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A cross-coupling calculation method based on unequal width magnetic circuit model, characterized in that: include: In a permanent magnet motor, a normalization method is used to add a permanent magnet equivalent magnetomotive force source to the large and small pole magnetic circuits of the d-axis to obtain a normalized large and small pole magnetic circuit model, wherein the magnetic circuit model is a d-axis-permanent magnet cross-coupling magnetic circuit model based on the normalized large and small pole magnetic circuit method; The magnetic isolation bridge part in the magnetic circuit model is adjusted to add permanent magnets, wherein the triangular area of ​​the large and small pole magnetic circuits of the magnetic circuit model before adjustment is not connected to the magnetic isolation bridge; In the large and small pole magnetic circuit with permanent magnet magnetomotive force, a path is connected between the triangular area between the permanent magnets and the magnetic isolation bridge to obtain a modified magnetic circuit model after the magnetic isolation bridge path is modified; The total magnetic flux and inductance of the loop are calculated by combining the modified magnetic circuit model and the corresponding equivalent magnetic circuit.

2. The cross-coupling calculation method based on the unequal width magnetic circuit model according to claim 1 is characterized in that: Before the permanent magnet motor uses the normalization method to add the permanent magnet equivalent magnetomotive force source to the large and small pole magnetic circuits of the d-axis to obtain the normalized large and small pole magnetic circuit model, the method further includes: Select any side of the magnetic circuit symmetry axis for analysis, and divide the stator space into large pole space and small pole space in turn according to the difference between the positive and negative values ​​of the magnetomotive force, wherein the large pole space contains the maximum positive and negative values ​​of the magnetomotive force in the neighborhood; Determine the magnetic circuit space according to the divided large pole space and small pole space, and divide the magnetic circuit into large and small pole spaces according to the magnetomotive force difference.

3. The cross-coupling calculation method based on the unequal width magnetic circuit model according to claim 2 is characterized in that: Determining the magnetic circuit space according to the divided large pole space and small pole space, and dividing the magnetic circuit of the large and small pole spaces of the magnetomotive force difference comprises: Based on the four magnetic circuit spaces of the electrode, the rotor is allocated to corresponding magnetic poles according to the proportion of the magnetic circuit space, so as to form a magnetic circuit topology corresponding to the four magnetic circuit spaces, wherein the four magnetic circuit spaces include two large pole spaces and two small pole spaces.

4. The cross-coupling calculation method based on the unequal width magnetic circuit model according to claim 1 is characterized in that: The adjusting of the magnetic isolation bridge part in the magnetic circuit model and adding permanent magnets, wherein the triangular area of ​​the large and small pole magnetic circuits before the adjustment of the magnetic circuit model is not connected to the magnetic isolation bridge, comprises: The added permanent magnet serves as an excitation source of the magnetic circuit. The flux generated by the magnetomotive force of the permanent magnet starts from the rotor side, and the magnetomotive force of the permanent magnet is greater than the magnetomotive force of the stator.

5. The cross-coupling calculation method based on the unequal width magnetic circuit model according to claim 1, characterized in that: In the magnetic circuit with permanent magnet magnetomotive force, a path is connected between the triangular area between the permanent magnets and the magnetic isolation bridge to obtain a modified magnetic circuit model after the magnetic isolation bridge path is modified, which includes: A path is connected between the triangular area between the permanent magnets and the magnetic isolation bridge, and the magnetic flux generated by the permanent magnet participates in the saturation of the magnetic isolation bridge, thereby obtaining a modified magnetic circuit model after the magnetic isolation bridge path is modified; The positions of the two large poles in the magnetic circuit model are modified consistently, and the positions of the two small poles are consistent with the d-axis small pole magnetic circuit.

6. The cross-coupling calculation method based on the unequal width magnetic circuit model according to claim 1, characterized in that: The total magnetic flux and inductance of the loop calculated by combining the modified magnetic circuit model and the corresponding equivalent magnetic circuit include: Combining the modified magnetic circuit model and the corresponding equivalent magnetic circuit, the loop equations are rewritten accordingly to obtain a rewritten loop equations; Based on the rewritten loop equations, the magnetic flux at each position is determined according to an iterative calculation method, and the total magnetic flux and inductance of the loop are calculated.

7. A cross-coupling calculation device based on a unequal width magnetic circuit model, characterized in that: include: An adding unit is used to add a permanent magnet equivalent magnetomotive force source to the large and small pole magnetic circuits of the d-axis in the permanent magnet motor by using a normalization method to obtain a normalized large and small pole magnetic circuit model, wherein the magnetic circuit model is a d-axis-permanent magnet cross-coupling magnetic circuit model based on the normalized large and small pole magnetic circuit method; An adjustment unit, used for adjusting the magnetic isolation bridge part in the magnetic circuit model to add a permanent magnet, wherein the triangular area of ​​the large and small pole magnetic circuits of the magnetic circuit model before adjustment is not connected to the magnetic isolation bridge; A connecting unit is used to connect the triangular area between the permanent magnets and the magnetic isolation bridge in the magnetic circuit with the large and small poles of the permanent magnet magnetomotive force to obtain a corrected magnetic circuit model after the magnetic isolation bridge path is corrected; The calculation unit is used to combine the modified magnetic circuit model and the corresponding equivalent magnetic circuit to calculate the total magnetic flux and inductance of the loop.

8. The cross-coupling calculation device based on the unequal width magnetic circuit model according to claim 7, further comprising: The first division unit is used to select any side of the magnetic circuit symmetry axis for analysis, and divide the stator space into a large pole space and a small pole space in sequence according to the magnitude of the positive and negative difference of the magnetomotive force, wherein the large pole space contains the maximum positive and negative values ​​of the magnetomotive force in the neighborhood; The second division unit is used to determine the magnetic circuit space according to the divided large pole space and small pole space, and to divide the magnetic circuit of the large and small pole spaces of the magnetomotive force difference.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium includes a stored program, wherein the program executes the method according to any one of claims 1 to 6 when executed.

10. An electronic device comprising a memory and a processor, characterized in that: A computer program is stored in the memory, and the processor is configured to execute the method according to any one of claims 1 to 6 through the computer program.

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