Variable flux memory motor design method based on novel hysteresis model

Abstract

The invention provides a variable flux memory motor design method based on a novel hysteresis model. The variable flux memory motor design method comprises the steps of S1, acquiring a first magnetization state point of a permanent magnet in a permanent magnet hysteresis model; s2, judging whether magnetizing or demagnetizing is needed or not: if so, turning to step S3; if not, returning to the step S1; s3, applying magnetizing current or demagnetizing current to update the magnetic field intensity; s4, determining a second magnetization state point after the first magnetization state point moves at the current moment, and updating the first-order magnetization ascending curve or the first-order magnetization descending curve for the first time; s5, the magnetizing current or the demagnetizing current is removed; and S6, determining a third magnetization state point after the second magnetization state point is moved at the current moment, updating the first-order magnetization rising curve or the first-order magnetization falling curve for the second time, and keeping the third magnetization state point for calculating motor parameters. The method has the beneficial effects that the magnetization characteristics of the aluminum-nickel-cobalt material can be accurately simulated, and the complexity is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of motor design and manufacture, and in particular to a design method of a variable flux memory motor based on a novel hysteresis model. Background Art

[0002] As a device that converts electrical energy into mechanical energy, the motor is widely used in industry, national defense, and daily life. With the development of science and technology, permanent magnet synchronous motors have become a research hotspot in the motor field due to their significant features such as high efficiency and high power density. Permanent magnet synchronous motors usually use permanent magnets as magnetic sources and adjust the air gap flux to achieve speed and power control. However, traditional permanent magnet motors have some problems, such as the difficulty in adjusting the air gap flux and limited weak magnetic capability.

[0003] In order to solve these problems of traditional permanent magnet synchronous motors, researchers proposed a variable flux memory motor (VFMM). The variable flux memory motor uses low coercive force permanent magnet aluminum nickel cobalt and changes the magnetization state of the permanent magnet by applying direct-axis pulse current, thereby achieving the adjustment of the air gap flux. This method avoids the copper loss caused by continuous direct-axis current during the weak magnetic process, improves the efficiency of the motor, and has a wide air gap flux adjustment range, so the motor has a wide speed operating range.

[0004] The core of variable flux memory motor to achieve air gap flux regulation lies in the unique magnetizing characteristics of low coercive force permanent magnet material AlNiCo. Therefore, accurate calculation of AlNiCo magnetizing performance is a key. The commonly used hysteresis model in low coercive force permanent magnet material is the parallelogram model. Although it can simulate the magnetizing characteristics of permanent magnets, it cannot accurately predict the magnetizing performance and the simulation results have too large errors. Therefore, how to propose a new hysteresis model that can accurately simulate the magnetizing characteristics of AlNiCo materials and reduce complexity as much as possible is a problem that needs to be solved urgently. Summary of the invention

[0005] The technical problem to be solved by the present invention is to accurately simulate the magnetization characteristics of aluminum nickel cobalt materials and reduce complexity. In order to overcome the defects of the above-mentioned prior art (or related technology), the present invention provides a variable flux memory motor design method based on a new hysteresis model.

[0006] The present invention provides a variable flux memory motor design method based on a novel hysteresis model, which is applied to a permanent magnet hysteresis model. The permanent magnet hysteresis model is formed by connecting a main magnetization curve and a main demagnetization curve to form a closed outer contour. A plurality of first-order magnetization rising curves and a plurality of first-order magnetization falling curves are connected between the main magnetization curve and the main demagnetization curve. The variable flux memory motor design method comprises the following steps: Step S1, controlling a variable flux memory motor to run, and obtaining a first magnetization state point of any permanent magnet in the variable flux memory motor in the permanent magnet hysteresis model; Step S2, determining whether the permanent magnet needs to be magnetized or demagnetized: If yes, go to step S3; If not, return to step S1; Step S3, applying a magnetizing current or a demagnetizing current to the permanent magnet to update the magnetic field strength so that the first magnetization state point moves along the first-order magnetization rising curve or the first-order magnetization falling curve; Step S4, determining a second magnetization state point after the first magnetization state point moves at the current moment and updating the first-order magnetization rising curve or the first-order magnetization falling curve for the first time; Step S5, removing the magnetizing current or the demagnetizing current to make the second magnetization state point move along the first-order magnetization rising curve or the first-order magnetization falling curve after the first update; Step S6, determining a third magnetization state point after the second magnetization state point moves at the current moment and updating the first-order magnetization rising curve or the first-order magnetization falling curve for the second time, and retaining the third magnetization state point for calculating motor parameters.

[0007] Compared with the prior art, the variable flux memory motor design method based on the new hysteresis model in this application has the following advantages: In the present application, the first magnetization state point is acquired through step S1, the charging and demagnetization requirements are judged through step S2, the charging and demagnetization current is applied through step S3, the second magnetization state point is determined through step S4, the charging and demagnetization current is removed through step S5, and the third magnetization state point is determined through step S6. The magnetization state points are used to more realistically represent the magnetization characteristics of the aluminum nickel cobalt material. The magnetization characteristics of the nonlinear material aluminum nickel cobalt permanent magnet can be more accurately simulated by moving the magnetization state points on the first-order magnetization rising curve or the first-order magnetization falling curve, and the accuracy of the mapping relationship between the parameters such as the motor air gap flux and the charging and demagnetization current is improved, thereby improving the accuracy of the motor design. In addition, the permanent magnet hysteresis model in the present application does not require a large amount of experimental data to construct a distribution function model, which greatly improves the calculation efficiency, achieves accurate simulation of the magnetization characteristics of the aluminum nickel cobalt material and reduces complexity.

[0008] In a possible implementation manner, before executing step S1, the method further includes: The main magnetization curve and the main demagnetization curve are connected end to end to form a closed area to obtain two curve connection points, and the curve connection point located in the first quadrant is used as the connection point corresponding to the positive maximum value, and the curve connection point located in the fourth quadrant is used as the connection point corresponding to the reverse maximum value.

[0009] In a possible implementation manner, before executing step S1, the main demagnetization curve is defined as: When the first magnetization state point is demagnetized at the positive maximum value, the first magnetization state point moves along the main demagnetization curve.

[0010] In a possible implementation manner, before executing step S1, the main magnetization curve is defined as: When the first magnetization state point is magnetized at the reverse maximum value, the first magnetization state point moves along the main magnetization curve.

[0011] In a possible implementation, before executing step S1, each of the first-order magnetization rising curves is defined as a family of curves of changes in the first magnetization state point and the second magnetization state point during magnetization.

[0012] In a possible implementation, before executing step S1, each of the first-order magnetization decline curves is defined as a family of curves of changes in the first magnetization state point and the second magnetization state point during demagnetization.

[0013] In a possible implementation manner, the variable flux memory motor design method further includes a motor parameter calculation process, and the motor parameter calculation process includes: Step A1, determining whether the variable flux memory motor needs to expand its speed range: If yes, turn to step S1, and turn to step A2 after obtaining the third magnetization state point; If not, return to step A1; Step A2: Calculate the corresponding motor parameters according to the third magnetization state point and the magnetic field strength at the current moment. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a flow chart of the steps of the present invention; Figure 2 It is a structural schematic diagram of the permanent magnet hysteresis model of the present invention; Figure 3 It is a schematic diagram of the magnetization state point movement of the present invention. DETAILED DESCRIPTION

[0015] First, those skilled in the art should understand that these implementations are only used to explain the technical principles of the embodiments of the present application, and are not intended to limit the protection scope of the embodiments of the present application. Those skilled in the art can make adjustments to them as needed to adapt to specific application scenarios.

[0016] The present application is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0017] See also Figure 1 The present application discloses a design method of a variable flux memory motor based on a novel hysteresis model, comprising: Step S1, controlling a variable flux memory motor to run, and obtaining a first magnetization state point of any permanent magnet in the variable flux memory motor in a permanent magnet hysteresis model; Step S2, determining whether the permanent magnet needs to be magnetized or demagnetized: If yes, go to step S3; If not, return to step S1; Step S3, applying a magnetizing current or a demagnetizing current to the permanent magnet to update the magnetic field strength so that the first magnetization state point moves along the first-order magnetization rising curve or the first-order magnetization falling curve; Step S4, determining a second magnetization state point after the first magnetization state point moves at the current moment and updating a first-order magnetization rising curve or a first-order magnetization falling curve for the first time; Step S5, removing the magnetization current or the demagnetization current to move the second magnetization state point along the first-order magnetization rising curve or the first-order magnetization falling curve after the first update; Step S6, determining a third magnetization state point after the second magnetization state point moves at the current moment and updating the first-order magnetization rising curve or the first-order magnetization falling curve for the second time, and retaining the third magnetization state point for calculating motor parameters.

[0018] The significance of the permanent magnet hysteresis model in this application is: since the change of magnetization intensity to magnetic field intensity is not a simple linear relationship, but has hysteresis, it is very important to accurately describe the relationship therebetween. The role of the permanent magnet hysteresis model is to describe the magnetization intensity B of the permanent magnet as accurately as possible, as the relationship changes with the magnetic field intensity H of the environment in which the permanent magnet is located. The permanent magnet hysteresis model is the premise of subsequent design calculations, and the accuracy of the permanent magnet hysteresis model affects the accuracy of subsequent design calculations.

[0019] The definition of the magnetization state point in the present application is: the permanent magnet in the operation of the variable flux memory motor will correspond to a certain magnetization state point in the permanent magnet hysteresis model, and will change with the change of the operating state of the variable flux memory motor. A more accurate permanent magnet hysteresis model can accurately determine the magnetization state point of the permanent magnet, and at the same time can improve the simulation accuracy of the finite element calculation method or the finite volume calculation method for describing the actual operating state of the variable flux memory motor.

[0020] The embodiment of the present application mainly proposes a novel permanent magnet hysteresis model, including the charging and demagnetization principle of the permanent magnet hysteresis model and the operation mechanism in the electromagnetic design software, wherein the permanent magnet hysteresis model includes a main magnetization curve, a main demagnetization curve, a first-order magnetization decrease curve, and a first-order magnetization increase curve. The meanings of the main magnetization curve and the main demagnetization curve are: when the magnetization state point is at the positive maximum value, if demagnetization is performed at this time, the magnetization state point will move along the main demagnetization curve; when the magnetization state point is at the reverse maximum value, if magnetization is performed at this time, the magnetization state point will move along the main magnetization curve; the main magnetization curve and the main demagnetization curve together constitute the outer contour of the permanent magnet hysteresis model; the magnetization state point of the permanent magnet is always determined above and within the outer contour of the permanent magnet hysteresis model; the structure of the permanent magnet hysteresis model is as follows: Figure 2 As shown; the meaning of the first-order magnetization decline curve is: it refers to the path curve of the change of the magnetization state point during demagnetization. Because the initial magnetization state points before demagnetization are different, the magnetization decline curve is a family of curves formed by various curves, collectively referred to as the first-order magnetization decline curve; the meaning of the first-order magnetization rise curve is: it refers to the path curve of the change of the magnetization state point during magnetization. Because the initial magnetization state points before magnetization are different, the magnetization rise curve is a family of curves formed by various curves, collectively referred to as the first-order magnetization rise curve.

[0021] The charging and demagnetization principle of the permanent magnet hysteresis model is: After the permanent magnet determines the magnetization state point, there will be a first-order magnetization decrease curve and a first-order magnetization increase curve corresponding to this point. During magnetization, the magnetization state point increases along the first-order magnetization increase curve corresponding to this moment, and during demagnetization, it decreases along the first-order magnetization decrease curve. After charging and demagnetization, a new magnetization state point is obtained, and the updated magnetization state point corresponds to the first-order magnetization decrease curve and the first-order magnetization increase curve.

[0022] like Figure 3As shown in the figure, when the variable flux memory motor is running, the permanent magnet magnetization state point is point A, at this time l1 is its corresponding first-order magnetization rising curve, l2 is the first-order magnetization falling curve, at this time, if you want to increase the speed, demagnetize the permanent magnet, apply demagnetization current, the magnetic field intensity H increases in the negative direction, the magnetization state point decreases along l2 to B, at this time, the first-order magnetization rising curve l3 and the first-order magnetization falling curve l2 are updated; at this time, the demagnetization current is cancelled, the magnetic field intensity H decreases in the positive direction, the magnetization state point changes along l3 to point C, at this time, the first-order magnetization rising curve l3 and the first-order magnetization falling curve l4 are updated; demagnetization is completed, and the C magnetization state point is added to the design calculation.

[0023] The charging and demagnetizing operation mechanism of the new permanent magnet hysteresis type in the design software is: When the variable flux memory motor needs to expand its speed range, the d-axis current is applied, and the software calculates the magnetic field strength at this moment. According to the charging and demagnetization principle of the permanent magnet hysteresis model, the updated magnetization strength of the permanent magnet is determined, and the calculation and design are started using the updated parameters of the permanent magnet.

[0024] Compared with the existing technology, the beneficial effects of the technical solution of the present application are as follows: 1. High-precision simulation: The new permanent magnet hysteresis model proposed in the present application not only takes into account the real magnetization characteristics of the aluminum nickel cobalt material, but also greatly reduces the complexity of the calculation. This permanent magnet hysteresis model can more accurately simulate the magnetization characteristics of the nonlinear material aluminum nickel cobalt permanent magnet, and improves the accuracy of the mapping relationship between parameters such as the motor air gap flux and the charging and demagnetizing current, thereby improving the accuracy of the motor design; 2. Improved calculation efficiency: Compared with the Preisach model, the permanent magnet hysteresis model of the present application does not require a large amount of experimental data to construct a distribution function model, which greatly improves the calculation efficiency; 3. Wide application: The permanent magnet hysteresis model of the present application is not only suitable for variable flux memory motors , and is also suitable for other motor designs that require accurate simulation of magnetization characteristics. In addition, since the computational complexity of the permanent magnet hysteresis model of the present application is low, it is also suitable for rapid simulation and optimization of large-scale motor designs; 4. Improve the speed regulation performance of the motor: Since the permanent magnet hysteresis model of the present application can more accurately simulate the magnetization characteristics of aluminum-nickel-cobalt materials, the operating point of the Alnico permanent magnet under different charging and demagnetization currents can be more accurately determined, thereby improving the speed regulation performance of the variable flux memory motor. Specifically, the permanent magnet hysteresis model of the present application can help designers better understand and predict the magnetization state and air gap flux changes of the variable flux memory motor, thereby optimizing the design and control of the variable flux memory motor and improving the efficiency and speed regulation performance of the variable flux memory motor.

[0025] Due to the advanced nature of the technical solution of the present application, it can be widely used in application fields such as motor design and manufacturing, magnetic material science, and control system engineering: In the field of motor design and manufacturing, the new permanent magnet hysteresis model proposed in the technical solution of the present application can greatly improve the calculation accuracy of the magnetization performance of low coercive force permanent magnets, thereby optimizing the design of variable flux memory motors, which can not only improve the efficiency of variable flux memory motors and expand the speed operating range of variable flux memory motors, but also reduce the manufacturing cost of variable flux memory motors and improve market competitiveness; In the field of magnetic material science, the new permanent magnet of the technical solution of the present application The hysteresis model can more accurately simulate the magnetization characteristics of the nonlinear material aluminum nickel cobalt permanent magnet, which is of great scientific significance for studying the magnetization properties of aluminum nickel cobalt materials and developing new magnetic materials; in the field of control system engineering, the new permanent magnet hysteresis model of the technical solution of the present application can be used to design and optimize control strategies, thereby improving the control accuracy and response speed of the variable flux memory motor, which is of important engineering value for improving the dynamic performance and stability of the variable flux memory motor; in general, the new permanent magnet hysteresis model of the technical solution of the present application has broad application prospects and market demand, and is expected to promote the development and progress of related technical fields.

[0026] In the description of the present application, the description with reference to the terms "one embodiment", "some embodiments", "in the present embodiment", "specific example", or "some examples" etc. means that the specific features, mechanisms, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, mechanisms, materials or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0027] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A design method for a variable flux memory motor based on a new hysteresis model, characterized in that: Applied to a permanent magnet hysteresis model, the permanent magnet hysteresis model is formed by connecting a main magnetization curve and a main demagnetization curve to form a closed outer contour, and multiple first-order magnetization rising curves and multiple first-order magnetization falling curves are connected between the main magnetization curve and the main demagnetization curve. The variable flux memory motor design method includes the following steps: Step S1, controlling a variable flux memory motor to run, and obtaining a first magnetization state point of any permanent magnet in the variable flux memory motor in the permanent magnet hysteresis model; Step S2, determining whether the permanent magnet needs to be magnetized or demagnetized: If yes, go to step S3; If not, return to step S1; Step S3, applying a magnetizing current or a demagnetizing current to the permanent magnet to update the magnetic field strength so that the first magnetization state point moves along the first-order magnetization rising curve or the first-order magnetization falling curve; Step S4, determining a second magnetization state point after the first magnetization state point moves at the current moment and updating the first-order magnetization rising curve or the first-order magnetization falling curve for the first time; Step S5, removing the magnetizing current or the demagnetizing current to make the second magnetization state point move along the first-order magnetization rising curve or the first-order magnetization falling curve after the first update; Step S6, determining a third magnetization state point after the second magnetization state point moves at the current moment and updating the first-order magnetization rising curve or the first-order magnetization falling curve for the second time, and retaining the third magnetization state point for calculating motor parameters.

2. The variable flux memory motor design method according to claim 1, characterized in that: Before executing step S1, the method further includes: The main magnetization curve and the main demagnetization curve are connected end to end to form a closed area to obtain two curve connection points, and the curve connection point located in the first quadrant is used as the connection point corresponding to the positive maximum value, and the curve connection point located in the fourth quadrant is used as the connection point corresponding to the reverse maximum value.

3. The variable flux memory motor design method according to claim 2, characterized in that: Before executing step S1, the main demagnetization curve is defined as: When the first magnetization state point is demagnetized at the positive maximum value, the first magnetization state point moves along the main demagnetization curve.

4. The variable flux memory motor design method according to claim 2, characterized in that: Before executing step S1, the main magnetization curve is defined as: When the first magnetization state point is magnetized at the reverse maximum value, the first magnetization state point moves along the main magnetization curve.

5. The variable flux memory motor design method according to claim 1, characterized in that: Before executing the step S1, each of the first-order magnetization rising curves is defined as a family of curves of changes in the first magnetization state point and the second magnetization state point during magnetization.

6. The variable flux memory motor design method according to claim 1, characterized in that: Before executing step S1, each of the first-order magnetization decline curves is defined as a family of curves of changes in the first magnetization state point and the second magnetization state point during demagnetization.

7. The variable flux memory motor design method according to claim 1, characterized in that: The variable flux memory motor design method further includes a motor parameter calculation process, which includes: Step A1, determining whether the variable flux memory motor needs to expand its speed range: If yes, turn to step S1, and turn to step A2 after obtaining the third magnetization state point; If not, return to step A1; Step A2: Calculate the corresponding motor parameters according to the third magnetization state point and the magnetic field strength at the current moment.

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