CN116796675A - Design method of axial magnetic field motor structure of yoke-free segmented armature - Google Patents
Design method of axial magnetic field motor structure of yoke-free segmented armature Download PDFInfo
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Abstract
The application discloses a design method of a structure of an axial magnetic field motor of a yoke-free segmented armature, which comprises the following steps: establishing an equivalent magnetic circuit model of the non-yoke segmented armature axial magnetic field motor, and performing magnetic flux analysis according to the equivalent magnetic circuit model to obtain the magnetic flux density and leakage coefficient of the motor; taking the inner diameter and outer diameter of the motor, the air gap magnetic flux density and the air gap length as optimization design variables, taking the power density, the efficiency and the material cost as an objective function of the optimization design, and carrying out multi-objective optimization according to preset constraint conditions to obtain the optimal value of the optimization design variables; and determining main design parameters of the axial magnetic field motor of the yoke-free segmented armature according to the magnetic flux density, the leakage coefficient and the optimal value of the optimal design variable. The application improves the precision of motor parameter design, has simple algorithm and can provide theoretical help for the design of the driving motor.
Description
Technical Field
The application relates to the technical field of driving motor design, in particular to a design method of a structure of a non-yoke segmented armature axial magnetic field motor.
Background
The electric energy is used as clean energy, has the characteristics of safety, economy, convenience in conversion and transportation and the like, and is widely focused and applied by the industry. The driving motor is used as a central system of the electric automobile, and the performance of the driving motor directly influences the running quality of the whole automobile. The Tesla electric automobile company adopts a three-phase induction motor as a driving device, the motor has the advantages of simpler structure, high working stability, convenience in daily maintenance and the like, and the disadvantages of low power density and more complex control system; electric automobile companies such as Biedi in China mostly adopt permanent magnet motors for driving, the motors are easy to regulate speed, high efficiency and high power density can be guaranteed when the automobile runs, but the motors are complex in structure and large in size, and installation occasions are greatly limited. Therefore, the torque density and the power density of the motor are improved on the basis of optimizing the motor structure, and the motor is significant in relation to the movement performance, the safety, the economy and the like of the electric automobile.
Document "Yan Jianhu, feng Yi. Magnetic focusing type transverse magnetic flux permanent magnet disk type wind driven generator design and analysis [ J ]. Chinese motor engineering journal 2017,37 (9): 2694.2700. "it is double stator, single rotor structure to propose the motor in the appearance, and the stator has two parts tooth bodies along radial direction, and the permanent magnet direction of magnetizing is circumference, because the motor adopts the magnetism structure that gathers, has reduced the magnetic leakage to a certain extent, has improved the size of every pole magnetic flux, and torque density has promoted. But the motor has larger size and structure and low complexity, and is only suitable for the concept stage.
Document "Su Shi, shi Yikai, cui Tiantian, yuan Xiaoqing, korean kang, ma Yan. Novel three-dimensional equivalent magnetic circuit study of disc-type transverse flux motor [ J ]. University of northwest industry journal, 2014, 32 (1): 142-146, a novel disk type transverse flux motor with an E-shaped stator core is designed, and the motor is suitable for being used as an electric automobile driving motor, and can fully play the space effect of an automobile hub. Establishing an equivalent magnetic network of the motor to calculate motor parameters, calculating air gap flux density, and making a prototype, wherein the magnetic flux is smaller, and the complex process of a node equation is higher;
the literature Chen Chen, wang is long again, axial flux permanent magnet motor optimization design based on efficiency and temperature rise [ J ]. Chinese motor engineering journal, 2016, 36 (6): 1686-1694' aiming at the problems of loss and heating of an axial motor, parameter optimization is carried out on a coreless axial flux permanent magnet motor by taking high-efficiency low-temperature rise as a target, eddy current loss generated by a motor winding is calculated by establishing an equivalent magnetic network model, a certain motor parameter is changed to test efficiency and temperature rise, and finally, all influencing factors are comprehensively considered to carry out multivariable multi-target optimization, but the cogging torque of the motor is larger, and the optimization effect of the structural parameter is less obvious. In addition, an equivalent magnetic circuit model of a variable network is also established, the change condition of air gap magnetic resistance of a stator and a rotor at different positions is considered through a finite element analysis method, the winding flux linkage of a motor can be directly solved, the complex process of calculating a node equation is simplified, and an experimental prototype is also manufactured, but the method has the problem of insufficient accuracy in specific application.
Disclosure of Invention
In view of at least one of the drawbacks or improvements of the prior art, the present application provides a method for designing a yoke-less segmented armature axial field motor structure, which aims to improve the accuracy of motor parameter design and reduce the complexity of the calculation process.
In order to achieve the above object, according to a first aspect of the present application, there is provided a method for designing a structure of a yoke-less segmented armature axial field motor, comprising the steps of:
establishing an equivalent magnetic circuit model of the non-yoke segmented armature axial magnetic field motor, and performing magnetic flux analysis according to the equivalent magnetic circuit model to obtain the magnetic flux density and leakage coefficient of the motor;
taking the inner diameter and outer diameter of the motor, the air gap magnetic flux density and the air gap length as optimization design variables, taking the power density, the efficiency and the material cost as an objective function of the optimization design, and carrying out multi-objective optimization according to preset constraint conditions to obtain the optimal value of the optimization design variables;
and determining main design parameters of the axial magnetic field motor of the yoke-free segmented armature according to the magnetic flux density, the leakage coefficient and the optimal value of the optimal design variable.
Further, in the design method of the axial magnetic field motor structure of the yoke-less segmented armature, the equivalent magnetic circuit model comprises a stator part equivalent magnetic circuit and a rotor part equivalent magnetic circuit;
the stator part equivalent magnetic circuit comprises a nonlinear reluctance R of ferromagnetic material t And R is sh Leakage magnetic flux R between core and permanent magnet s Leakage magnetic flux R between adjacent cores ss The method comprises the steps of carrying out a first treatment on the surface of the Wherein each part is calculated as:
wherein L is act Representing the effective length of the stator, i.e. the difference between the outer radius and the inner radius; g s ,L bar ,L sh ,h sh ,L s And L ss Respectively are provided withRepresenting the axial height of the stator, the length of the rod, the length of the tooth shoe, the height of the tooth shoe, the width of the slot and the distance between two adjacent tooth shoes;
the rotor part equivalent magnetic circuit comprises a nonlinear reluctance R of a rotor core r Equivalent magnetomotive force source F m Reluctance R of permanent magnet m Leakage magnetic flux R from permanent magnet to permanent magnet mm And reluctance R corresponding to leakage flux from permanent magnet to air gap mg The method comprises the steps of carrying out a first treatment on the surface of the Wherein each part is calculated as:
wherein H is c ,μ r ,B r Respectively representing coercive force, relative magnetic permeability and remanence of the permanent magnet; h is a m L m Representing the height and length of the permanent magnet, L ms Representing the distance between two adjacent permanent magnets.
In the method for designing the structure of the axial magnetic field motor of the yoke-less segmented armature, the main design parameters of the axial magnetic field motor of the yoke-less segmented armature determined according to the magnetic flux density, the leakage coefficient and the optimal value of the optimal design variable are respectively as follows:
the axial length of the rotor is the length L of the rotor core cs And permanent magnetBody thickness L pm The sum of, i.e
In which B is u Representing the magnetic flux density of the permanent magnet surface; b (B) cr Representing the rotor core magnetic flux density; mu (mu) r Representing the relative permeability of the permanent magnet; b (B) r Representing the residual magnetic density of the permanent magnet; b (B) g Indicating the air gap flux density; k (k) f Representing the air gap flux density correction coefficient; k (k) d Indicating leakage magnetic coefficient; k (K) c Representing the card-type coefficient; g represents the air gap length;
the axial length of the stator depends on the air gap flux density, the flux density in the stator core, and the inner and outer diameters of the motor, i.e
Wherein alpha is p A ratio representing the average air gap flux density and the peak air gap flux density; b (B) cs A magnetic flux density representing the stator core; d (D) o Represents the outer diameter of the motor; p represents the pole pair number of the motor; lambda represents the internal-external ratio value of the motor.
The axial effective length of the motor is:
L e ＝2L r +L s +2g
the output power of the axial permanent magnet motor is as follows:
in which K is Φ Representing the ratio of the rotor electrical load to the stator electrical load; m is m 1 Representing the number of phases per stator; k (K) e Representing the electromotive force coefficient; k (K) i Representing the current waveform coefficient; a represents an electrical load; f represents the motor frequency.
Further, in the design method of the yoke-less segmented armature axial magnetic field motor structure, the parameter types in the constraint condition include one or more of an inner diameter and an outer diameter of the motor, an air gap length, an air gap flux density, an axial effective length, an output power, a phase voltage effective value, efficiency, pole pair number and a phase number.
Further, in the design method of the yoke-free segmented armature axial magnetic field motor structure, a weight coefficient transformation method is adopted to realize multi-objective genetic algorithm solution, and power density, efficiency and material cost optimization results under different weight coefficients and optimal values of corresponding optimization design variables are obtained; and selecting the optimal value of the corresponding optimal design variable under the corresponding weight coefficient based on the required objective function interval.
Further, in the design method of the structure of the axial magnetic field motor of the yoke-less segmented armature, each permanent magnet in the axial magnetic field motor of the yoke-less segmented armature has a magnetic pole offset so as to inhibit cogging torque.
Further, in the design method of the axial magnetic field motor structure of the yoke-free segmented armature, the magnetic pole offset angle of the permanent magnet is 4 degrees.
Further, in the design method of the structure of the axial magnetic field motor of the yoke-free segmented armature, the torque of the axial magnetic field motor of the yoke-free segmented armature is proportional to the power of the third power of the outer diameter of the motor, and the stator part is free of a magnetic yoke.
In general, the above technical solutions conceived by the present application, compared with the prior art, enable the following beneficial effects to be obtained:
(1) The design method of the axial magnetic field motor structure of the yoke-free segmented armature fully considers the problems of armature reaction and permanent magnet magnetic leakage to establish an equivalent magnetic circuit model of the motor, comprises a stator part magnetic circuit model and a rotor part magnetic circuit model, analyzes counter electromotive force and electromagnetic torque of the motor according to the equivalent magnetic circuit model, and has high accuracy; and then, taking the inner diameter and outer diameter of the motor, the air gap magnetic flux density and the air gap length as optimal design variables, taking the power density, the efficiency and the material cost as an objective function of optimal design to perform multi-objective optimization, obtaining the optimal value of the optimal design variables, further determining main design parameters of the yoke-free segmented armature axial magnetic field motor, solving the problem of low accuracy of calculated motor parameters, and being beneficial to improving the torque density and the power density of the electric automobile driving motor. The algorithm is simple, has strong practicability and can provide theoretical assistance for the design of a driving motor.
(2) According to the design method of the axial magnetic field motor structure of the yoke-free segmented armature, provided by the application, each permanent magnet in the motor has magnetic pole offset, and after the permanent magnet transmits the offset, the cogging torque can be reduced by 70.6% at most, so that the effective suppression of the cogging torque is realized.
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In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present application, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic flow chart of a design method of a structure of a yoke-free segmented armature axial magnetic field motor according to an embodiment of the present application;
fig. 2 is a schematic diagram of a topological structure of a stator yoke-less modular axial motor according to an embodiment of the present application;
fig. 3 is a schematic diagram of a magnetic circuit structure of a yoke-less segmented armature axial field motor according to an embodiment of the present application;
fig. 4 is a schematic structural diagram of an equivalent magnetic circuit model of a yoke-less segmented armature axial field motor according to an embodiment of the present application; wherein, fig. 4 (a) is a stator part equivalent magnetic circuit model, and fig. 4 (b) is a rotor part equivalent magnetic circuit model;
FIG. 5 is a schematic diagram of a curved surface relationship of motor power density according to the change of the outer diameter and the inner-outer diameter ratio value according to the embodiment of the application;
FIG. 6 is a schematic diagram of a curved surface relationship of motor efficiency according to the change of the outer diameter and the inner-outer diameter ratio according to the embodiment of the application;
fig. 7 is a schematic diagram of a cogging torque curve of a motor provided by an embodiment of the present application under different permanent magnet offset angles;
fig. 8 is a schematic diagram of a permanent magnet offset 4 ° distribution provided in an embodiment of the present application;
FIG. 9 is a graph comparing cogging torque waveforms before and after permanent magnet misalignment provided by an embodiment of the present application;
fig. 10 is a schematic diagram of a motor magnetic field distribution generated based on a three-dimensional finite element analysis method according to an embodiment of the present application.
Detailed Description
The present application will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present application more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the application. In addition, the technical features of the embodiments of the present application described below may be combined with each other as long as they do not collide with each other.
The terms first, second, third and the like in the description and in the claims and in the above drawings, are used for distinguishing between different objects and not necessarily for describing a particular sequential or chronological order. Furthermore, the terms "comprise" and "have," as well as any variations thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, system, article, or apparatus that comprises a list of steps or elements is not limited to only those listed steps or elements but may include other steps or elements not listed or inherent to such process, method, article, or apparatus.
Furthermore, well-known or widely-used techniques, elements, structures, and processes may not be described or shown in detail in order to avoid obscuring the understanding of the present application by the skilled artisan. Although the drawings represent exemplary embodiments of the present application, the drawings are not necessarily to scale and certain features may be exaggerated or omitted in order to better illustrate and explain the present application.
Fig. 1 is a flow chart of a design method of a structure of a yoke-less segmented armature axial magnetic field motor according to the present embodiment, referring to fig. 1, the method includes the following steps:
step one, establishing an equivalent magnetic circuit model of the axial magnetic field motor of the non-yoke segmented armature, and carrying out magnetic flux analysis according to the equivalent magnetic circuit model to obtain the magnetic flux density and the leakage coefficient of the motor;
in the embodiment, the axial magnetic field motor of the yoke-free segmented armature is of a double-rotor single-stator structure, is a new-structure axial permanent magnet motor with a stator of no magnetic yoke and modularization, and can be used for a regenerative braking system of an electric vehicle. Fig. 2 shows a topological structure diagram of the axial permanent magnet motor with the stator in a yoke-free modularized mode, and as shown in fig. 2, the motor adopts a middle stator and two-side double-rotor structure, and corresponding permanent magnets on two rotor plates are in an N-S structure. The stator plate is composed of a plurality of (typically 12) SMC cores and coils thereon, which are independent of each other, and each coil is connected to form a three-phase symmetrical winding. In order to fully utilize the isotropic magnetic properties of the SMC material, the tooth shoe portions of each core block protrude radially beyond the tooth body portion so that the coil ends are within the effective magnetic field of the motor.
Because the magnetic flux does not pass through the stator yoke, the yoke can be made thin, thereby being beneficial to reducing the iron loss of the motor and improving the operation efficiency. The magnetic circuit structure of the motor is shown in fig. 3.
The stator adopts a modularized structure, is free of a magnetic yoke and consists of a plurality of same small modules, and can simplify the manufacturing and assembling processes of the axial permanent magnet motor. The iron core in the small module can be stacked by silicon steel sheets, and can also be made of soft magnetic composite materials or amorphous alloy and other novel materials, and the winding is directly wound on an insulating material outside the iron core. The axial permanent magnet motor stator with the structure has the advantages of small iron loss, short winding end part and high slot filling rate, and is beneficial to improving the power density and efficiency of the motor. Furthermore, the yolkless structure also allows for weight reduction of the stator core.
The torque of the axial magnetic field of the motor with the yoke-free segmented armature axial magnetic field is proportional to the power of the outer diameter of the motor to the third power, and is irrelevant to the axial length of the motor. This means that in the profile condition of D > > L (outer diameter much larger than overlap) the torque will be much higher than for the radial motor.
Firstly, establishing an equivalent magnetic circuit model of the yoke-free segmented armature axial magnetic field motor, wherein the equivalent magnetic circuit model consists of four main parts: rotor core, permanent magnet, air gap and stator core; the equivalent magnetic circuit model fully considers the problems of armature reaction and permanent magnet magnetic leakage, and has high accuracy; the back electromotive force and the electromagnetic torque of the motor are analyzed according to the equivalent magnetic circuit model, and the problem of low accuracy of calculating the motor parameters can be solved.
Fig. 4 is a schematic diagram of an equivalent magnetic circuit model of the axial magnetic field motor with the yoke-less segmented armature provided in the present embodiment, in which fig. 4 (a) is a stator portion equivalent magnetic circuit model, and fig. 4 (b) is a rotor portion equivalent magnetic circuit model.
For the equivalent magnetic circuit model of the stator part, the ferromagnetic material part of the equivalent magnetic circuit model is formed by nonlinear magnetic resistance R t And R is sh Modeling, they are painted black, a source of magnetic fluxIs introduced to take into account armature reaction, leakage flux through the slots is measured by reluctance R s Modeling, leakage magnetic flux between two adjacent cores is determined by reluctance R ss It is contemplated that the values of these magnetoresistances may be calculated by:
wherein L is act Representation and determinationThe effective length of the sub, i.e. the difference between the outer radius and the inner radius; h is a s ,L bar ,L sh ,h sh ,L s And L ss Respectively representing the axial height of the stator, the length of the rod, the length of the tooth shoe, the height of the tooth shoe, the width of the groove and the distance between two adjacent tooth shoes; relative permeability mu of stator core r (B) As a function of magnetic flux density, an iterative process may be taken from the B-H curve of the SMC material to take into account saturation.
For the rotor part equivalent magnetic circuit model, the permanent magnet of the rotor part equivalent magnetic circuit model is modeled by considering an air gap and herringbone leakage magnetic flux, and comprises an equivalent magnetomotive force source F m Reluctance R of permanent magnet m Leakage magnetic flux reluctance R between permanent magnets mm And reluctance R corresponding to leakage flux from permanent magnet to air gap mg As shown in fig. 4 (b). Likewise, the rotor core is formed by nonlinear magnetic resistance R r Modeling to account for magnetic saturation.
The above-mentioned magnetic resistance and magnetomotive force can be calculated as follows:
wherein H is c ,μ r ,B r Respectively representing coercive force, relative magnetic permeability and remanence of the permanent magnet; h is a m L m Representing the height and length of the permanent magnet, L ms Representing the distance between two adjacent permanent magnets.
Taking the inner diameter and outer diameter of the motor, the air gap magnetic flux density and the air gap length as optimal design variables, taking the power density, the efficiency and the material cost as an objective function of optimal design, and performing multi-objective optimization according to preset constraint conditions to obtain an optimal value of the optimal design variables;
the embodiment selects the power density, the efficiency and the economy as the objective function of the optimal design, and the optimal design variable is selected as the inside-outside diameter ratio value lambda and the outside diameter D o Air gap flux density B g And an air gap length g. Realizing multi-objective optimization design, and solving Pareto optimal solution of the multi-objective optimization problem; the optimization objective function is expressed as:
f obj (P den ,η,M mat )＝f(λ,D o ,B g ,g).
in which P is den -power density;
η -motor efficiency;
M mat efficient material costs.
In addition, the optimization design variable is limited by the constraint of electromagnetic and mechanical properties, and the optimization design variable should be valued in a reasonable variation range. The constraints and design requirements for an axial permanent magnet motor are shown in table 1.
TABLE 1 axial permanent magnet machine constraint and design requirements
The stator yoke-free modularized axial permanent magnet motor is subjected to multi-objective optimization design through a genetic algorithm, different weight coefficients are set, and the optimization design targets of small motor size, high power density, high efficiency and good economy are realized on the premise of meeting the rated technical requirements. The genetic algorithm optimization design results taking power density, efficiency and material cost as objective functions under 5 groups of different weight coefficients are shown in table 2.
Table 2 results of axial permanent magnet motor optimization design
As can be seen from Table 2, the optimization objective functions do not have a single coupling relationship, coordination and compromise among the optimization objectives are involved in the actual engineering application process, and according to the actual design requirement, the optimal design meeting the specific requirement can be realized by selecting different weight coefficients.
For the convenience of analysis, a curved surface schematic diagram of the motor power density and efficiency changing along with the outer diameter and the inner-outer diameter ratio is obtained by interpolation, and is shown in fig. 4 and 5 respectively. As can be seen from fig. 4, the outer diameter Do and the inner-outer diameter ratio λ change to show a fluctuating state on the power density effect, and there is a multi-peak and non-single mapping relationship, and the genetic algorithm can find the optimal solution in the global range through limited iteration. As can be seen from fig. 5, the efficiency tends to increase with the increase in the ratio of the outer diameter to the inner diameter, but the increase rate gradually decreases, and the optimization is most suitable when the stator size is 0.70 in the ratio of the inner diameter to the outer diameter and 122.86 in the outer diameter.
In order to verify the distribution of the magnetic flux density under different stator sizes, the axial permanent magnet motor has a special structural form, so that the distribution of the magnetic flux density along the axial direction represents the 3D effect of 'edge effect'. In the embodiment, the influence of the effect is considered by adopting three-dimensional finite element analysis, so that an electromagnetic field analysis result with higher accuracy can be obtained. The 3 rd group data in Table 2 is selected to carry out electromagnetic design of the stator yoke-free modularized axial permanent magnet motor, and the optimized power density and efficiency are 3.054W/cm respectively 3 And 92.1%.
And thirdly, determining main design parameters of the axial magnetic field motor of the yoke-free segmented armature according to the magnetic flux density, the leakage coefficient and the optimal value of the optimal design variable.
In one specific example, the main design parameters of a yoke-less segmented armature axial field motor include, but are not limited to, determining the inner by genetic algorithmOuter diameter ratio lambda, outer diameter D o Air gap flux density B g And an air gap length g, and an axial length L of the rotor core cs Axial length (i.e. thickness) L of permanent magnet pm Axial length L of stator core s Axial effective length L of motor e Output power P of motor out Etc.; the specific calculation is as follows:
the axial length of the rotor is the length L of the rotor core cs Thickness L with permanent magnet pm The sum of, i.e
In which B is u Representing the magnetic flux density of the permanent magnet surface; b (B) cr Representing the rotor core magnetic flux density; mu (mu) r Representing the relative permeability of the permanent magnet; b (B) r Representing the residual magnetic density of the permanent magnet; b (B) g Indicating the air gap flux density; k (k) f Representing the air gap flux density correction coefficient; k (k) d Indicating leakage magnetic coefficient; k (K) c Representing the card-type coefficient; g represents the air gap length;
the axial length of the stator depends on the air gap flux density, the flux density in the stator core, and the inner and outer diameters of the motor, i.e
Wherein alpha is p A ratio representing the average air gap flux density and the peak air gap flux density; b (B) cs A magnetic flux density representing the stator core; d (D) o Represents the outer diameter of the motor; p represents the pole pair number of the motor; lambda represents the internal-external ratio value of the motor.
The axial effective length of the motor is:
L e ＝2L r +L s +2g
the overall power density of the axial permanent magnet motor is as follows:
D t ＝D o +2W cu
in the formula W cu -single-sided length of the two end winding ends;
D t -the overall outer diameter of the motor.
The output power of the axial permanent magnet motor is as follows:
in which K is Φ Representing the ratio of the rotor electrical load to the stator electrical load; m is m 1 Representing the number of phases per stator; k (K) e Representing the electromotive force coefficient; k (K) i Representing the current waveform coefficient; a represents an electrical load; f represents the motor frequency.
In one specific example, the main parameters of the final determined axial permanent magnet machine are shown in table 3.
TABLE 3 main parameters of axial permanent magnet Motor
In a more preferred embodiment, each permanent magnet in the yoke-less segmented armature axial field motor has a pole offset, suppressing cogging torque. In one specific example, the pole offset variable values are shown in table 4.
Table 4 magnetic pole offset variable values
To maintain the same spacing between poles after the poles are offset, θ 1 、θ 2 Shall be maintained at θ 1 ＝3θ 2 Is a relationship of (3).
Simulation calculation is carried out on a motor model with the set magnetic pole offset parameter variable through Ansoft software, and a generated cogging torque curve chart is shown in fig. 7. Through calculation, after the permanent magnet transmits the offset, the cogging torque can be reduced by 70.6% at most, so that the effective suppression of the cogging torque is realized, and the optimal offset angle of the corresponding magnetic pole is about 4 degrees. Fig. 8 shows a schematic distribution diagram of permanent magnet offset by 4 °, and fig. 9 shows a comparative diagram of cogging torque waveforms before and after offset; it can be seen that the waveform of the cogging torque fluctuates less than the waveform in which no shift occurs after setting the permanent magnet shift.
The motor model is simulated based on a three-dimensional finite element method, and the generated open magnetic field distribution is shown in fig. 10. The rotor position θm is defined as 0 ° (mechanical position), and as can be seen from fig. 10, the magnetic flux reaches a negative maximum value and a positive maximum value, respectively, and the maximum flux density is about 1.1T, and if the influence of the harmonic component and the local saturation effect is not considered, sinusoidal back electromotive force can be generated in the armature winding, greatly improving the magnetic flux.
It should be noted that while in the above-described embodiments the operations of the methods of the embodiments of the present specification are described in a particular order, this does not require or imply that the operations must be performed in that particular order or that all of the illustrated operations be performed in order to achieve desirable results. Rather, the steps depicted in the flowcharts may change the order of execution. Additionally or alternatively, certain steps may be omitted, multiple steps combined into one step to perform, and/or one step decomposed into multiple steps to perform.
The foregoing is merely exemplary embodiments of the present disclosure and is not intended to limit the scope of the present disclosure. That is, equivalent changes and modifications are contemplated by the teachings of this disclosure, which fall within the scope of the present disclosure. Embodiments of the present disclosure will be readily apparent to those skilled in the art from consideration of the specification and practice of the disclosure herein. This application is intended to cover any variations, uses, or adaptations of the disclosure following, in general, the principles of the disclosure and including such departures from the present disclosure as come within known or customary practice within the art to which the disclosure pertains. It is intended that the specification and examples be considered as exemplary only, with a scope and spirit of the disclosure being indicated by the claims.
The technical features of the above embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.
It will be readily appreciated by those skilled in the art that the foregoing description is merely a preferred embodiment of the application and is not intended to limit the application, but any modifications, equivalents, improvements or alternatives falling within the spirit and principles of the application are intended to be included within the scope of the application.
Claims (8)
1. The design method of the axial magnetic field motor structure of the non-yoke segmented armature is characterized by comprising the following steps of:
establishing an equivalent magnetic circuit model of the non-yoke segmented armature axial magnetic field motor, and performing magnetic flux analysis according to the equivalent magnetic circuit model to obtain the magnetic flux density and leakage coefficient of the motor;
taking the inner diameter and outer diameter of the motor, the air gap magnetic flux density and the air gap length as optimization design variables, taking the power density, the efficiency and the material cost as an objective function of the optimization design, and carrying out multi-objective optimization according to preset constraint conditions to obtain the optimal value of the optimization design variables;
and determining main design parameters of the axial magnetic field motor of the yoke-free segmented armature according to the magnetic flux density, the leakage coefficient and the optimal value of the optimal design variable.
2. The design method of the structure of the yoke-less segmented armature axial field motor of claim 1, wherein the equivalent magnetic circuit model comprises a stator part equivalent magnetic circuit and a rotor part equivalent magnetic circuit;
the stator part equivalent magnetic circuit comprises a nonlinear reluctance R of ferromagnetic material t And R is sh Leakage magnetic flux R between core and permanent magnet s Leakage magnetic flux R between adjacent cores ss The method comprises the steps of carrying out a first treatment on the surface of the Wherein each part is calculated as:
wherein L is act Representing the effective length of the stator, i.e. the difference between the outer radius and the inner radius; h is a s ,L bar ,L sh ,h sh ,L s And L ss Respectively representing the axial height of the stator, the length of the rod, the length of the tooth shoe, the height of the tooth shoe, the width of the groove and the distance between two adjacent tooth shoes;
the rotor part equivalent magnetic circuit comprises a nonlinear reluctance R of a rotor core r Equivalent magnetomotive force source F m Reluctance R of permanent magnet m Leakage magnetic flux R from permanent magnet to permanent magnet mm And reluctance R corresponding to leakage flux from permanent magnet to air gap mg The method comprises the steps of carrying out a first treatment on the surface of the Wherein each part is calculated as:
wherein H is c ,μ r ,B r Respectively representing coercive force, relative magnetic permeability and remanence of the permanent magnet; h is a m L m Representing the height and length of the permanent magnet, L ms Representing the distance between two adjacent permanent magnets.
3. The method for designing a structure of a yokeless segmented armature axial field motor of claim 1, wherein the main design parameters of the yokeless segmented armature axial field motor determined according to the magnetic flux density, the leakage coefficient and the optimal value of the optimal design variable are respectively:
the axial length of the rotor is the length L of the rotor core cs Thickness L with permanent magnet pm The sum of, i.e
In which B is u Representing the magnetic flux density of the permanent magnet surface; b (B) cr Representing the rotor core magnetic flux density; mu (mu) r Representing the relative permeability of the permanent magnet; b (B) r Representing the residual magnetic density of the permanent magnet; b (B) g Indicating the air gap flux density; k (k) f Representing the air gap flux density correction coefficient; k (k) d Indicating leakage magnetic coefficient; k (K) c Representing the card-type coefficient; g represents the air gap length;
the axial length of the stator depends on the air gap flux density, the flux density in the stator core, and the inner and outer diameters of the motor, i.e
Wherein alpha is p A ratio representing the average air gap flux density and the peak air gap flux density; b (B) cs A magnetic flux density representing the stator core; d (D) o Represents the outer diameter of the motor; p represents the pole pair number of the motor; lambda represents the internal-external ratio value of the motor.
The axial effective length of the motor is:
L e ＝2L r +L s +2g
the output power of the axial permanent magnet motor is as follows:
in which K is Φ Representing the ratio of the rotor electrical load to the stator electrical load; m is m 1 Representing the number of phases per stator; k (K) e Representing the electromotive force coefficient; k (K) i Representing the current waveform coefficient; a represents an electrical load; f represents the motor frequency.
4. A method of designing a structure for a yokeless segmented armature axial field motor as claimed in any one of claims 1-3, wherein the types of parameters in the constraints include one or more of an inside-outside ratio, an outside diameter, an air gap length, an air gap flux density, an axial effective length, an output power, a phase voltage effective value, an efficiency, a pole pair number, and a phase number of the motor.
5. The design method of the structure of the axial magnetic field motor of the non-yoke segmented armature according to any one of claims 1 to 3, wherein a weight coefficient transformation method is adopted to realize multi-objective genetic algorithm solution, and optimal values of power density, efficiency, material cost optimization results and corresponding optimization design variables under different weight coefficients are obtained; and selecting the optimal value of the corresponding optimal design variable under the corresponding weight coefficient based on the required objective function interval.
6. A method of designing a structure of a yokeless segmented armature axial field motor as in any one of claims 1-3 wherein each permanent magnet in the yokeless segmented armature axial field motor has a pole offset to suppress cogging torque.
7. The method of designing a yokeless segmented armature axial field motor structure of claim 6, wherein the permanent magnet has a pole offset angle of 4 °.
8. A method of designing a yokeless segmented armature axial field motor structure as in any one of claims 1-7 wherein the torque of the axial field of the yokeless segmented armature axial field motor is proportional to the power of the outside diameter of the motor and the stator portion is yoked.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN117318355A (en) * | 2023-11-28 | 2023-12-29 | 黑龙江惠达科技股份有限公司 | Unmanned aerial vehicle's motor and unmanned aerial vehicle |
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| CN117318355A (en) * | 2023-11-28 | 2023-12-29 | 黑龙江惠达科技股份有限公司 | Unmanned aerial vehicle's motor and unmanned aerial vehicle |
| CN117318355B (en) * | 2023-11-28 | 2024-02-09 | 黑龙江惠达科技股份有限公司 | Unmanned aerial vehicle's motor and unmanned aerial vehicle |
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