Optimization Method for Curved Magnetic Barrier Design of Synchronous Reluctance Motor and a Synchronous Reluctance Motor

Abstract

The present invention relates to an optimization method for the design of a curved magnetic barrier of a synchronous reluctance motor and a synchronous reluctance motor. When constructing a finite element model of the motor, a curve equation with adjustable left endpoint position, abscissa of the curve peak, and ordinate of the curve peak is used in the rotor design domain to construct the magnetic barrier boundary. By adjusting the adjustable coefficients in the curve equation, a unimodal curve of any shape can be obtained. The magnetic barrier of the synchronous reluctance motor is parametrically modeled using the coefficients of the curve equation, breaking the limitation of using a specific curve as the design magnetic barrier boundary in the existing curved magnetic barrier design. When designing, there is no need to consider the specific curve shape, and many irregular curves can be obtained through the optimization of the coefficients. This method constructs the magnetic barrier boundary through a function, parameterizes the synchronous reluctance motor using the coefficients of the function, improves the torque and efficiency through optimization, reduces the torque ripple, and significantly improves the motor performance.

Description

Technical Field:

[0001] The present invention relates to the technical field of motors, and more particularly to a synchronous reluctance motor with a curved magnetic barrier structure, especially the design of the rotor magnetic barrier structure of the synchronous reluctance motor. Background Art:

[0002] Compared with a DC motor, a synchronous reluctance motor does not require a commutator and brushes, simplifies the motor structure, has high operating reliability and low maintenance rate; compared with an induction motor, a synchronous reluctance motor eliminates the squirrel-cage bars and excitation windings on the rotor, avoids the iron loss on the rotor, improves the efficiency, and saves the rotor manufacturing cost; compared with a permanent magnet synchronous motor, a synchronous reluctance motor does not require permanent magnets, does not use rare earth elements, and only uses the torque of the reluctance property as the motor torque, greatly reducing the motor manufacturing cost. Under the background of the global energy crisis, synchronous reluctance motors have received extensive attention due to their high power density, simple structure, low cost, and low maintenance rate.

[0003] The d-axis reluctance of the synchronous reluctance motor is small, and the magnetic flux is easy to flow through. The q-axis is the high-reluctance direction and the magnetic flux is not easy to flow through. The synchronous reluctance motor uses the principle of the minimum reluctance in the magnetic flux flow path to generate the reluctance torque, and the magnitude of the reluctance torque is related to the ratio of the d-axis and q-axis inductance values. The greater the difference between the d-axis inductance and the q-axis inductance, the greater the reluctance torque of the synchronous reluctance motor; the smaller the difference between the d-axis inductance and the q-axis inductance, the smaller the reluctance torque of the synchronous reluctance motor. In order to increase the inductance difference between the d and q axes, multiple layers of magnetic barriers are punched on the rotor of the synchronous reluctance motor. The multiple layers of magnetic barriers can increase the d-axis inductance, reduce the q-axis inductance, and thus increase the saliency ratio, enabling the synchronous reluctance motor to obtain an ideal torque characteristic.

[0004] The performance of the synchronous reluctance motor is jointly affected by factors such as the operating environment, material parameters, and topological structure, which makes it difficult to improve the performance of the synchronous reluctance motor. An increase in performance exceeding 5% is regarded as a significant performance improvement, and an increase in performance exceeding 1% can be regarded as a slight performance improvement. The multi-layer magnetic barriers of traditional synchronous reluctance motors use a straight-line design. The magnetic barrier structure designed with a straight-line shape has few design dimensions. Only 5 dimensions, namely the position, height, width, swing angle, and length of the magnetic barrier, can be designed and optimized. And for each, before and after optimization, it is difficult to effectively increase the torque, reduce the torque ripple, and improve the efficiency. Moreover, the existing curve design is obtained by interpolation, which is time-consuming for optimization. In addition, when there are too many intersections of non-smooth broken lines, it will cause too high local magnetic fields, resulting in problems such as overheating of silicon steel and vibration.

[0005] Publication No. CN113315437A uses the difference modeling method to establish the magnetic barrier boundary of any shape. The torque of a two-layer magnetic barrier synchronous reluctance motor is increased by 2.8%, and the torque ripple is reduced by 50.3%. However, the interpolation points are connected by straight lines. If too few interpolation points are taken, obvious inflection points will appear, and the hysteresis eddy current loss at the inflection points will increase, which will seriously affect the efficiency of the synchronous reluctance motor and also limit the further improvement of the torque performance. If a large number of interpolation points are selected, the shape of the curve is close to smooth, but the time for calculating the interpolation points increases, affecting the optimization duration. Summary of the Invention:

[0006] Aiming at the deficiencies of the prior art, the technical problem to be solved by the present invention is to provide an optimization method for the curved-edge magnetic barrier design of a synchronous reluctance motor and a synchronous reluctance motor.

[0007] The technical solution adopted by the present invention to solve the above technical problems is:

[0008] An optimization method for the curved-edge magnetic barrier design of a synchronous reluctance motor, the process of the optimization method is:

[0009] The first step is to construct a synchronous reluctance motor model with a straight magnetic barrier:

[0010] Each rotor pole includes k layers of magnetic barriers MB 1 , MB 2 , …, MB k , taking the pole symmetry axis as the y-axis and the center of the rotor core as the origin O to establish a Cartesian coordinate system. Each layer of magnetic barrier is divided into left and right parts by the pole symmetry axis. The right half of each layer of magnetic barrier includes upper and lower edges The upper and lower edges of the right half of each layer of magnetic barrier are further divided into two straight lines perpendicular to the y-axis and the extension line that intersects the y-axis but is not perpendicular.

[0011] The right endpoint of the straight line perpendicular to the y-axis coincides with the left endpoint of the extension line that intersects the y-axis but is not perpendicular. The abscissa of the coincidence point is represented by and the ordinate of the coincidence point is represented by ;

[0012] And obtain the average torque Taveini, torque ripple Tripini and efficiency η of the synchronous reluctance motor model with a straight magnetic barrier at the above coincidence point ini ;

[0013]

[0014] These four types of parameters are selected based on experience to construct a linear magnetic barrier synchronous reluctance motor as the motor to be optimized. The first two types of parameters of the motor to be optimized remain unchanged during the subsequent curvilinear modeling and optimization process and are regarded as fixed parameters, while the last two types of parameters can be optimized after curvilinear modeling and are regarded as variable parameters.

[0015] In the second step, use the curve equation in Equation (1) for modeling to obtain the curved edge. The right endpoint of the curved edge coincides with the coincidence point in the first step, and the change range of the independent variable in the equation satisfies Equation (2);

[0016]

[0017]

[0018] Among them, are the curve modeling equations of the upper and lower magnetic barrier boundaries of the 1st to kth magnetic barriers respectively. and are the coefficients in the formula. Changing the values of the coefficients can change the position of the curve peak and the ordinate of the curve peak.

[0019] The left endpoint of the curve is on the y-axis, so the abscissa of the left endpoint of all curves is 0, that is, the ordinate of the left endpoint of each curve can be obtained as:

[0020]

[0021] It can be seen that the ordinate of the left endpoint of each curve will change with and the changes of these three parameters. By adjusting the above three parameters, the position of the left endpoint of each curve on the y-axis can be changed. The abscissa of the right endpoint of each curve is Substituting into the formula, the ordinate of the right endpoint of each curve is calculated as

[0022] and The two groups of parameters do not change after constructing the linear magnetic barrier synchronous reluctance motor, so it can be considered that the right endpoint is fixed.

[0023] The abscissa of the curve peak and the ordinate of the curve peak are respectively:

[0024]

[0025]

[0026] Among them, represents the abscissa of the curve peak point; represents the ordinate of the curve peak;

[0027] According to the formula for the abscissa of the peak value of the curve, while keeping unchanged and only adjusting the abscissa of the peak value of the curve can be adjusted left and right. The abscissa of the peak value of the curve is not affected by The ordinate of the peak value of the curve is affected by these three parameters at the same time.

[0028] It can be seen that by using this curve equation for modeling, a curve with a fixed right endpoint, a left endpoint that can move up and down along the y-axis, and adjustable abscissa and ordinate of the peak value of the curve can be obtained. Adjusting the three parameters in the formula can achieve all unimodal curve shapes within the parameter variation range.

[0029] When the curve degenerates into a straight line in the modeling of the linear magnetic barrier synchronous reluctance motor to be optimized, and the same linear magnetic barrier synchronous reluctance motor as before the replacement is obtained.

[0030] Derive the upper and lower two curve edges of each magnetic barrier on the right side of the y-axis, use the derivative value of the right endpoint as the slope of the upper and lower two straight line edges of each magnetic barrier on the right side of the y-axis, and update the slope of the straight line to Equation (6):

[0031]

[0032] The lengths of the upper and lower two straight line edges of each magnetic barrier on the right side of the y-axis are used From this, the straight line modeling equations for the upper and lower two straight line edges of each magnetic barrier on the right side of the y-axis using Equation (7) can be obtained, and the variation range of the independent variable satisfies Equation (8);

[0033]

[0034]

[0035] Among them, is the modeling equation for the upper and lower two straight line edges of each magnetic barrier on the right side of the y-axis, and are the coefficients of the equation. When the curve equation is fixed, is fixed, and by changing the coefficient the length of the straight line can be changed.

[0036] The boundary of the left half of each layer of magnetic barrier is symmetric about the y-axis with respect to the boundary of the right half. Connect the right endpoints of the straight line parts of the upper and lower two sides of each layer of magnetic barrier. Thus, the modeling of the k-layer magnetic barrier of one rotor pole is completed; then rotate the rotor pole with the modeling of all k-layer magnetic barriers completed by a certain angle to obtain the finite element model of the motor;

[0037] In the third step, optimize the variable coefficients in the curve modeling equation and the straight-line modeling equation and with the optimization objective of maximizing the average torque Tave and efficiency η and minimizing the torque ripple Trip. The weights are set to 0.3, 0.3, and 0.4 respectively for the optimization design, and the combined optimization objective equation is Equation (9);

[0038]

[0039] where Tave, Trip, and η are the torque, torque ripple, and efficiency; Tave ini , Trip ini and η ini are respectively the torque, torque ripple, and efficiency of the synchronous reluctance motor with a magnetic barrier to be optimized.

[0040] In the fourth step, select the variation range of each coefficient for different positions of the magnetic barrier, input these coefficients to be optimized into the optimization algorithm, and optimize them to obtain the optimal magnetic barrier shape using the curvilinear modeling design method of the synchronous reluctance motor.

[0041] The present invention also provides a synchronous reluctance motor, characterized in that the motor includes a stator core, an armature winding, a rotor core, and a magnetic barrier; there are k layers of magnetic barriers distributed radially along the motor under each rotor pole of the rotor core, a magnetic conduction bridge is formed between adjacent two layers of magnetic barriers under the same rotor pole, the shape of each layer of magnetic barrier is left-right symmetric, and the curve parts of the upper and lower two boundaries on the right half of the y-axis of each layer of magnetic barrier are modeled using the curve equation of Equation (1), and the variation range of the independent variable satisfies (2);

[0042]

[0043]

[0044] where are respectively the curve modeling equations of the upper and lower magnetic barrier boundaries of the 1st to kth layers of magnetic barriers. and are the coefficients in the formula.

[0045] The straight-line parts of the upper and lower two boundaries on the right half of the y-axis of each layer of magnetic barrier are modeled using the straight-line equation of Equation (7), and the range of the independent variable satisfies Equation (8);

[0046]

[0047]

[0048] where is the modeling equation of the upper and lower two straight sides of each magnetic barrier on the right side of the y-axis, and are the coefficients of the equation.

[0049] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0050] 1. When constructing the finite element model of the motor, the present invention uses a curve equation with adjustable left endpoint position, abscissa of the curve peak, and ordinate of the curve peak in the rotor design domain to construct the magnetic barrier boundary. By adjusting the adjustable coefficients in the curve equation, a single-peak curve of any shape can be obtained. The magnetic barrier of the synchronous reluctance motor is parametrically modeled using the coefficients of the curve equation, breaking the limitation of using a specific curve as the design magnetic barrier boundary in the existing curved-edge magnetic barrier design. When designing, it is not necessary to consider the specific curve shape, and many irregular curves can be obtained through the optimization of the coefficients.

[0051] 2. When modeling the straight part of the magnetic barrier, the present invention uses the slope of the curve equation at the right endpoint as the slope of the straight line. Each layer of the constructed magnetic barrier can reduce two inflection points, and a smoother magnetic barrier boundary is beneficial to the improvement of the motor performance.

[0052] 3. The present invention uses an optimization method to optimize the parametric curve coefficients. Since the coefficients of the curve equation do not have actual geometric meanings and multiple parameters jointly construct the curve edge, many novel irregular magnetic barrier shapes that cannot be predicted theoretically can be obtained through optimization. Using the novel irregular magnetic barrier shape can reduce the quadrature-axis inductance, increase the direct-axis inductance, increase the difference between the direct-axis and quadrature-axis inductances, and increase the electromagnetic torque of the motor. At the same time, the magnetic reluctance torque ripple generated by the difference between the direct-axis and quadrature-axis inductances becomes smaller, so the torque ripple of the motor is reduced. Under this rotor shape, the torque performance of the motor is improved.

[0053] 4. Compared with the existing curve interpolation modeling method, the curved-edge magnetic barrier modeling method of the present invention does not require interpolation calculation, has a faster modeling speed, and the optimization time for each time is shortened. The curve constructed by using the curve equation for the whole curve is smooth. Compared with the modeling method using straight line segments for each section in the interpolation modeling, the improvement of the motor performance is more obvious. Since the curve modeling equation is limited to optimizing in the form of a single-peak curve, the optimization accuracy is higher than that of topology optimization, and the optimized shape is smooth and meets the manufacturing requirements. Description of the Drawings:

[0054] Attached Figure 1 shown is the radial cross-sectional view of the synchronous reluctance motor of the present invention.

[0055] Attached Figure 2 shown is the three-dimensional structural schematic diagram of the rotor of the synchronous reluctance motor of the present invention.

[0056] Attached Figure 3 shown is the radial cross-sectional view of the rotor of the synchronous reluctance motor with a straight magnetic barrier to be optimized.

[0057] Attached Figure 4 Shown is a curve of the change in the abscissa of the peak value of a set of curves obtained by adjusting the curve modeling coefficient of the present invention.

[0058] Attached Figure 5 Shown is a curve of the change in the ordinate of the peak value of a set of curves obtained by adjusting the curve modeling coefficient of the present invention.

[0059] Attached Figure 6 Shown is a curve of the left end point of a set of curves obtained by adjusting the curve modeling coefficient of the present invention swinging up and down on the y-axis.

[0060] Attached Figure 7 Shown is a schematic diagram of the rotor three-layer magnetic barrier modeling in the embodiment of the present invention.

[0061] Attached Figure 8 Shown is a radial cross-sectional view of the rotor of the synchronous reluctance motor optimized by the present invention.

[0062] Attached Figure 9 Shown is a torque comparison diagram of the optimized curved-edge magnetic barrier synchronous reluctance motor (optimized motor) and the to-be-optimized straight-edge magnetic barrier synchronous reluctance motor (pre-optimized motor) at a rated current density of 6 A / mm 2 at that time.

[0063] Attached Figure 10 Shown is the speed-torque-efficiency diagram of the to-be-optimized straight-line magnetic barrier synchronous reluctance motor (pre-optimized motor) at a rated current density of 6 A / mm 2 of.

[0064] Attached Figure 11 is the speed-torque-efficiency diagram of the optimized curved-edge magnetic barrier synchronous reluctance motor (optimized motor) at a rated current density of 6 A / mm 2 of.

[0065] Legend: 1. Stator core; 2. Three-phase symmetric winding; 3. Rotor core; 4. Air gap; 5. Magnetic barrier; 6. Shaft; 7. Curve of the change in the abscissa of the peak value of a set of curves obtained by changing the coefficients of the curve modeling equation; 8. Curve of the change in the ordinate of the peak value of a set of curves obtained by changing the coefficients of the curve modeling equation; 9. Curve of the left end point moving up and down on the y-axis obtained by changing the coefficients of the curve modeling equation. Specific implementation manner:

[0066] For the attached drawings of the present invention, it should be understood that a certain exemplary example within the scope of protection of the present invention has guiding significance for those skilled in the art to implement the corresponding technical solutions, rather than a limitation to the present invention.

[0067] The present invention will be further described below in conjunction with the attached drawings.

[0068] An optimization method for the curved magnetic barrier design of a synchronous reluctance motor of the present invention (hereinafter referred to as the method) includes the following steps:

[0069] In the first step, a synchronous reluctance motor model is constructed using the traditional straight magnetic barrier modeling method. Each rotor pole includes k layers of magnetic barriers MB 1 , MB 2 , …, MB k ; Each layer of magnetic barrier is divided into left and right parts by the pole symmetry axis, and the left and right parts of the magnetic barrier are mirror-symmetrical about the pole symmetry axis. Taking the pole symmetry axis as the y-axis and the center of the rotor core as the origin O, a Cartesian coordinate system is established. The right half of each layer of magnetic barrier includes upper and lower edges where the superscript of L represents the corresponding magnetic barrier layer, the subscript 1 represents the lower edge, and the subscript 2 represents the upper edge; the upper and lower edges of the right half of each layer of magnetic barrier are further divided into two straight lines perpendicular to the y-axis and the extension line intersecting the y-axis but not perpendicular. Each straight line perpendicular to the y-axis of the right half of each layer of magnetic barrier is represented by , its left endpoint is on the y-axis, and the ordinate of the right endpoint is the same as that of the left endpoint, represented by , and the abscissa of the right endpoint is represented by . Each straight line whose extension line intersects the y-axis but is not perpendicular of the right half of each layer of magnetic barrier is represented by , its left endpoint coincides with the right endpoint, and the slope of the straight line whose extension line intersects the y-axis but is not perpendicular is , and the length of the straight line whose extension line intersects the y-axis but is not perpendicular is

[0070]

[0071] These four types of parameters are selected based on experience to construct a straight magnetic barrier synchronous reluctance motor as the motor to be optimized. The first two types of parameters of the motor to be optimized (i.e., the ordinate and abscissa of the right endpoint of the straight line perpendicular to the y-axis) do not change during the subsequent curved edge modeling and optimization process and are regarded as fixed parameters, while the last two types of parameters (the slope of the straight line whose extension line intersects the y-axis but is not perpendicular and the distance between the right and left endpoints of the straight line whose extension line intersects the y-axis but is not perpendicular) can be optimized after the curved edge modeling and are regarded as variable parameters.

[0072] In the second step, the straight line perpendicular to the y-axis in the straight magnetic barrier boundary synchronous reluctance motor is deleted, and the curve equation of Equation (1) is used for modeling to form a curved edge, so that the right endpoint of the obtained curved edge is the same as the right endpoint of the straight line perpendicular to the y-axis in the straight magnetic barrier boundary synchronous reluctance motor, and the change range of the independent variable in the equation satisfies Equation (2);

[0073]

[0074]

[0075] Among them, are respectively the curve modeling equations of the upper and lower magnetic barrier boundaries of the 1st to kth magnetic barriers; is the abscissa value of any point on the curve side of the upper and lower magnetic barrier boundaries of the 1st to kth magnetic barriers, and are the coefficients in the formula. Changing the values of the coefficients can change the position of the curve peak and the ordinate of the curve peak.

[0076] The left end point of the curve side is on the y-axis. Therefore, the abscissas of the left end points of all curve sides are 0. That is, the ordinate of the left end point of each curve can be obtained by the formula (3) as:

[0077]

[0078] It can be seen that the ordinate of the left end point of each curve will change with and These three parameters change. By adjusting the above three parameters, the position of the left end point of each curve on the y-axis can be changed. The abscissa of the right end point of each curve is Substituting into formula (1) to calculate the ordinate of the right end point of each curve, which is also

[0079] and The two groups of parameters do not change after constructing the linear magnetic barrier synchronous reluctance motor. Therefore, it can be considered that the right end point is fixed.

[0080] The abscissa of the curve peak and the ordinate of the curve peak are respectively:

[0081]

[0082]

[0083] Among them, represents the abscissa of the curve peak; represents the ordinate of the curve peak. According to the formula of the abscissa of the curve peak of the curve, keeping unchanged and only adjusting can adjust the abscissa of the curve peak left and right. The abscissa of the curve peak is not affected by . The ordinate of the curve peak is affected by these three parameters at the same time.

[0084] It can be seen that by using this curve equation for modeling, a curve with a fixed right endpoint, a left endpoint that can move up and down the y-axis, and adjustable peak abscissa and peak ordinate can be obtained. Adjusting the three parameters in the formula can achieve all unimodal curve shapes within the parameter variation range.

[0085] When the curve degenerates into a straight line in the modeling of the linear magnetic barrier synchronous reluctance motor to be optimized, and the same linear magnetic barrier synchronous reluctance motor as before the replacement is obtained.

[0086] Derive the upper and lower two curve edges of each magnetic barrier on the right side of the y-axis (derivative of formula (1) with respect to x), and take the derivative value of the right endpoint as the slope of the upper and lower two extension lines of each magnetic barrier on the right side of the y-axis that intersect but are not perpendicular to the y-axis (i.e., the straight line edge), and update the slope of the straight line edge to formula (6):

[0087]

[0088] The lengths of the upper and lower two straight line edges (extension lines that intersect but are not perpendicular to the y-axis) of each magnetic barrier on the right side of the y-axis are calculated using From this, the linear modeling equations of the upper and lower two straight line edges of each magnetic barrier on the right side of the y-axis can be obtained using formula (7), and the variation range of the independent variable satisfies formula (8);

[0089]

[0090]

[0091] Among them, is the linear modeling equation of the upper and lower two straight line edges of each magnetic barrier on the right side of the y-axis, and are the coefficients of the equation. When the curve equation is fixed, is fixed, and by changing the coefficient the length of the straight line can be changed.

[0092] The boundary of the left half of each layer of magnetic barrier is symmetric about the y-axis with respect to the boundary of the right half. Connect the right endpoints of the straight line edges of the upper and lower two sides of each layer of magnetic barrier. Thus, the k-layer magnetic barrier modeling of one rotor pole is completed; then rotate the rotor pole with all k-layer magnetic barriers modeled by a certain angle to obtain the finite element model of the motor;

[0093] In the third step, the variable coefficients and Optimize it, taking the maximum of the average torque \(T_{ave}\) and efficiency \(\eta\) and the minimum of the torque ripple \(T_{rip}\) as the optimization objectives, and setting the weights to 0.3, 0.3, and 0.4 respectively for the optimization design. The combined optimization objective is given by Equation (9);

[0094]

[0095] where \(T_{ave}\), \(T_{rip}\), and \(\eta\) are the torque, torque ripple, and efficiency respectively; \(T_{ave}\) ini , \(T_{rip}\) ini and \(\eta\) ini are the torque, torque ripple, and efficiency of the linear magnetic barrier synchronous reluctance motor to be optimized respectively.

[0096] In the fourth step, for different positions of the magnetic barriers (different values of \(k\), different positions of the magnetic barrier curves), select the variation ranges of each coefficient (\(A\), \(P\), \(h\), \(D\)), input these coefficients to be optimized into the optimization algorithm (such as intelligent algorithms like genetic algorithm, ant algorithm, etc.), optimize them, and obtain the optimal magnetic barrier shape using the curvilinear modeling design method of the synchronous reluctance motor.

[0097] As Figures 1 to 2 shown, a synchronous reluctance motor of the present invention includes: a stator core 1, a three-phase symmetric winding 2, a rotor core 3, an air gap 4 between the stator core and the rotor core, a magnetic barrier 5, a rotating shaft 6, etc. There are 3 layers of flux barriers distributed radially along the motor under each rotor pole. A magnetic conduction bridge is formed between adjacent magnetic barriers under each rotor pole, so that the magnetic barriers and magnetic isolation grooves under each rotor pole are alternately distributed. The three layers of magnetic barriers under each rotor pole are symmetric about the pole symmetry axis. The upper and lower boundaries of each layer of magnetic barrier are modeled by combining curves and straight lines. The upper and lower magnetic barriers are irregular in shape, neither parallel nor intersecting. The purpose is to increase the inductance difference between the direct axis and the quadrature axis. Under the excitation of symmetric three-phase currents, the larger the reluctance torque generated by the synchronous reluctance motor using the inductance difference between the direct and quadrature axes, the smaller the torque ripple.

[0098] The rotor core 3 and the stator core 1 are laminated with silicon steel sheets; the air gap 4 between the stator core and the rotor core is set to 0.5 mm; the three-phase symmetric winding 2 is arranged in the grooves formed by multiple teeth of the stator core 3, wound around the periphery of the teeth along the axial direction of the motor, and forms a closed axial end on the front, rear, left, and right four faces of the teeth.

[0099] Embodiment

[0100] A method for optimizing the curvilinear magnetic barrier design of a synchronous reluctance motor in this embodiment (see Figures 1 - 7 ) includes the following steps:

[0101] Step 1: Design a linear magnetic barrier synchronous reluctance motor according to the given motor size, and select the number of magnetic barrier layers as 3. The motor size and materials are as follows:

[0102] Outer diameter of stator: 70 mm

[0103] Inner diameter of stator: 40 mm

[0104] Outer diameter of rotor: 39.5 mm

[0105] Inner diameter of rotor: 10 mm

[0106] Axial length of motor: 69 mm

[0107] The stator core and rotor core are laminated with 50JN350 silicon steel sheets. The rotor core has 4 rotor poles, and each rotor pole includes three layers of magnetic barriers. The stator core has 24 slots, the number of wires in each slot is 30, and the slot fill factor is 43%. Establish the designed linear magnetic barrier synchronous reluctance motor in the finite element software, and verify whether the selected linear magnetic barrier position and size parameters meet the requirements. The right endpoint of the straight line perpendicular to the y-axis coincides with the left endpoint of the straight line whose extension line intersects the y-axis but is not perpendicular to the y-axis, and the abscissa of the coincidence point of the linear magnetic barrier synchronous reluctance motor that meets the requirements is represented by and the ordinate of the coincidence point is represented by ;

[0108] And obtain the average torque Taveini, torque ripple Tripini and efficiency η of the linear magnetic barrier synchronous reluctance motor model at the above coincidence point ini ;

[0109] In this embodiment, there are three layers of magnetic barriers, so k = 3 is taken.

[0110] Step 2: Establish a Cartesian coordinate system with the polar symmetry axis of a rotor pole as the y-axis. Calculate the ordinates and abscissas of the right endpoints of the upper and lower 6 vertical sides of the three layers of magnetic barriers on the right side of the y-axis of the magnetic barriers of the designed linear magnetic barrier synchronous reluctance motor. These parameters remain unchanged in the subsequent design optimization of the curved magnetic barrier. Figure 3 is the linear magnetic barrier synchronous reluctance motor to be optimized.

[0111] Delete the straight line boundaries perpendicular to the y-axis of each layer of magnetic barrier in the right half of the y-axis, and use the curve equation shown in Equation (10) with the ordinate of the right endpoint as and the abscissa of the right endpoint as for modeling. The change range of the independent variable is shown in Equation (11)

[0112]

[0113]

[0114] In Equations (10) and (11), respectively represent the modeling equations of the upper and lower curve boundaries of the 1st - 3rd layer magnetic barriers; The coefficients of these 18 curve modeling equations can be used as the parameters to be optimized and input into the optimization algorithm.

[0115] The constructed curve has a single peak, and the abscissa of the curve peak satisfies Equation (12), and the ordinate of the curve peak satisfies Equation (13);

[0116]

[0117]

[0118] It can be seen from Equations (13) and (14) that the abscissa of the peak is related to these 12 parameters. When these 6 parameters remain unchanged, by changing the ordinate of the curve peak can be adjusted. The ordinate of the curve peak is related to all these 18 parameters. The coordinates of the peak point are input into the optimization algorithm as part of the parameters to be optimized. Figures 4 - 6 are the curve shapes of the lower boundary of the first - layer magnetic barrier that can be constructed using these 8 parameters.

[0119] Let be updated to the slope of the curve at the right - hand endpoint, and the new is as shown in Equation (15);

[0120]

[0121] It can be seen from Equation (15) that after the coefficients in the curve equation are determined, the slope of the straight line is a fixed value. The only variable quantity is the length of the straight line. Use Equation (16) to construct the upper and lower straight - line sides on the right - hand side of the y - axis of each layer of magnetic barrier, and the change range of the independent variable satisfies Equation (17);

[0122]

[0123]

[0124] In Equations (16) and (17), represent the modeling equations of the upper and lower straight - line sides of the 1st - 3rd layer magnetic barriers; The coefficients of these 6 straight - line equations can be input into the optimization algorithm for optimization.

[0125] The left - hand part of the magnetic barrier boundary is obtained by mirror - symmetry of the right - hand part of the magnetic barrier boundary about the y - axis. By connecting the right - hand endpoints of the upper and lower straight - line edges of each layer of the magnetic barrier, a complete three - layer magnetic barrier model is obtained. Furthermore, a pre - optimization model of a synchronous reluctance motor with a curved magnetic barrier boundary is obtained. The parameters of the pre - optimization model selected in this embodiment are Degenerate the curve into a straight line. The selected is the same as the design parameters of a linear - magnetic - barrier synchronous reluctance motor, and a synchronous reluctance motor with a curved - edge magnetic barrier modeling before optimization, which is the same as the synchronous reluctance motor with a linear magnetic barrier to be optimized, is obtained. Figure 8 is a schematic diagram of the curved - edge modeling of a rotor pole after selecting parameter values according to the above method.

[0126] In the third step, take as parameters for optimization. Taking the performance of the synchronous reluctance motor before optimization as the initial value, an optimization model is established using Equation (9).

[0127]

[0128] In Equation (9), Tave, Trip, and η are torque, torque ripple, and efficiency; Tave ini , Trip ini , and η ini are 8.835 Nm, 26.44%, and 0.871 respectively.

[0129] In the fourth step, perform optimization to find the optimal design points of 24 optimization parameters. The 24 parameters obtained after optimization are shown in Table 1.

[0130] Table 1 Optimal design points of 24 optimization parameters

[0131]

[0132] Figure 9 shows the torque comparison diagram between the synchronous reluctance motor with a curved - edge magnetic barrier after optimization (optimized motor) and the synchronous reluctance motor with a linear magnetic barrier to be optimized (pre - optimized motor) in this embodiment. It can be seen from the figure that the torque of this embodiment is 9.480 Nm, the torque ripple is 14.98%, and the torque of this embodiment is increased by 7.29% compared with the pre - optimized motor. In Embodiment 1, the torque ripple is reduced by 43.34% compared with the pre - optimized motor. The torque and torque ripple of this embodiment have obvious performance improvements compared with the pre - optimized motor.

[0133] Figure 10 and Figure 11 respectively show the speed - torque - efficiency diagrams of the synchronous reluctance motor with a linear magnetic barrier to be optimized (pre - optimized motor) and the synchronous reluctance motor with a curved - edge magnetic barrier after optimization (optimized motor) in this embodiment. FromFigure 10 and Figure 11 It can be seen from Figure 11 that the efficiency of this embodiment under the rated speed condition is 88.04%, which is 1.15% higher than that of the motor before optimization. The efficiency characteristic of this embodiment is slightly improved compared with the motor before optimization.

[0134] In summary, this embodiment has greatly improved the torque characteristic compared with the motor before optimization, effectively reducing the torque ripple and improving the rated operating efficiency of the motor, thus proving the feasibility of the present invention.

[0135] The method proposed by the present invention can effectively optimize the magnetic barrier boundary of the synchronous reluctance motor and obtain the optimal rotor shape. This method is also applicable to the multi-layer flux barrier synchronous reluctance motor and the multi-pole pair synchronous reluctance motor.

[0136] The above-described embodiments are only used to describe the technical solutions of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention.

[0137] Matters not described in the present invention are applicable to the prior art.

Claims

1. A method for optimizing the design of a curved magnetic barrier in a synchronous reluctance motor, characterized in that The method includes the following steps: First step, construct a synchronous reluctance motor model with a linear magnetic barrier: Each rotor pole includes k layers of magnetic barriers MB 1 , MB 2 , …, MB k , taking the pole symmetry axis as the y-axis and the center of the rotor core as the origin O to establish a Cartesian coordinate system. Each layer of magnetic barrier is divided into left and right parts by the pole symmetry axis. The right half of each layer of magnetic barrier includes upper and lower edges The upper and lower edges of the right half of each layer of magnetic barrier are further divided into two straight lines perpendicular to the y-axis and intersecting the y-axis but not perpendicularly The right endpoint of the straight line perpendicular to the y-axis coincides with the left endpoint of the straight line that intersects the y-axis but is not perpendicular to the extension line, and the abscissa of the coincident point is obtained by is represented by, and the ordinate of the coincident point is represented by is represented by; And obtain the average torque Tave, torque ripple Trip ini ini , and torque ripple Trip ini ini and efficiency η ini ini ; Second step, use the curve equation of Equation (1) for modeling to obtain the curve side. The right endpoint of the curve side coincides with the coincidence point in the first step, and the variation range of the independent variable in the equation satisfies Equation (2); Among them, are respectively the curve modeling equations of the upper and lower magnetic barrier boundaries of the 1st to kth magnetic barriers; is the abscissa value of any point on the curve edge of the upper and lower magnetic barrier boundaries of the 1st to kth magnetic barriers, and are the coefficients in the formula, The left endpoint of the curve side is on the y-axis, so the abscissas of the left endpoints of all curve sides are 0, that is, the ordinates of the left endpoints of each curve are obtained as follows: The abscissa and ordinate of the curve peak are respectively: Among them, represents the abscissa of the peak point of the curve; represents the ordinate of the peak of the curve; Using this curve equation for modeling can obtain a curve with a fixed right endpoint, a left endpoint moving up and down on the y-axis, and adjustable abscissa and ordinate of the curve peak; Derive the upper and lower curve sides of each magnetic barrier on the right side of the y-axis, and use the derivative value of the right endpoint as the slope of the upper and lower straight sides of each magnetic barrier on the right side of the y-axis. The slope formula of the straight side is Equation (6): The lengths of the upper and lower straight edges of each magnetic barrier on the right side of the y-axis are represented by , and the linear modeling equations for the upper and lower straight edges of each magnetic barrier on the right side of the y-axis are obtained as formula (7), where the range of variation of the independent variable satisfies equation (8); Among them, is the linear modeling equation of the upper and lower two straight edges of each magnetic barrier on the right side of the y-axis; is the independent variable; and are the coefficients of the equation; when the curve equation is fixed, is fixed, and by changing the coefficient the length of the straight line is changed; The left half of the boundary of each layer of magnetic barrier is symmetric about the y-axis with respect to the right half of the boundary. Connect the right endpoints of the straight sides of the upper and lower sides of each layer of magnetic barrier. Thus, the modeling of the k-layer magnetic barrier of one rotor pole is completed; then rotate the rotor pole with the completed modeling of all k-layer magnetic barriers by a certain angle to obtain the finite element model of the motor; Step 3: Optimize the variable coefficients in the curve modeling equation and the straight line modeling equation and Optimize them. Take the maximum of the average torque Tave and the efficiency η and the minimum of the torque ripple Trip as the optimization objectives, and set the weights to 0.3, 0.3, and 0.4 respectively for the optimization design. The combined optimization objective equation is Equation (9); Fourth step, select the variation range of each variable coefficient for different positions of the magnetic barriers, input these coefficients to be optimized into the optimization algorithm, and optimize them to obtain the optimal magnetic barrier shape using the synchronous reluctance motor curved edge modeling design method.

2. A synchronous reluctance motor optimized by using the optimization method for the curved magnetic barrier design of the synchronous reluctance motor described in claim 1, characterized in that, The motor includes a stator core, an armature winding, a rotor core, and a magnetic barrier; k layers of magnetic barriers are radially distributed along the motor under each rotor pole of the rotor core. A magnetic conduction bridge is formed between adjacent two layers of magnetic barriers under the same rotor pole. The shape of each layer of magnetic barrier is left-right symmetric, and the upper and lower boundaries of each layer of magnetic barrier are designed using irregular curves.

3. The synchronous reluctance motor according to claim 2, wherein, The curve parts of the upper and lower boundaries of each layer of magnetic barrier on the right side of the y-axis are modeled using the curve equation of Equation (1), and the variation range of the independent variable satisfies (2); Among them, are respectively the curve modeling equations of the upper and lower magnetic barrier boundaries of the 1st to kth magnetic barriers; and are the coefficients in the formula; the straight-line parts of the upper and lower two boundaries on the right half of the y-axis of each magnetic barrier are modeled using the straight-line equation of Equation (7), and the range of the independent variable satisfies Equation (8); Among them, is the modeling equation of the upper and lower two straight edges of each magnetic barrier on the right side of the y-axis, and are the coefficients of the equation.

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