Equivalent restoring force analysis method and system for springless linear oscillation motor

Abstract

The invention discloses an equivalent restoring force analysis method and system for a springless linear oscillation motor, and belongs to the technical field of electromagnetic field analysis and calculation. Considering that a ferromagnetic material has a saturation characteristic, winding current excitation is applied to an electromagnetic finite element model of the springless linear oscillation motor, and magnetic conductivity distribution of the ferromagnetic material in the motor under winding current excitation is solved; then, magnetic conductivity distribution of a ferromagnetic material in the motor under winding current excitation is imported into the electromagnetic finite element model, after winding current excitation is removed, the current electromagnetic finite element model is solved, and magnetic density distribution of the ferromagnetic material in the motor after winding current excitation is removed and magnetic density distribution of an air gap space corresponding to a rotor are obtained; and obtaining the current equivalent restoring force of the motor. According to the method, the influence of winding current excitation is fully considered, the effect of coupling magnetic field separation is achieved through the process, and the equivalent restoring force of the motor can be accurately analyzed in the load running state of the springless linear oscillation motor.

Description

Technical Field

[0001] The present invention belongs to the technical field of electromagnetic field analysis and calculation, and more specifically, relates to an equivalent restoring force analysis method and system for a springless linear oscillation motor. Background Art

[0002] Linear Oscillatory Machine (LOM) can directly realize the conversion of electrical energy into linear reciprocating mechanical energy. It has the advantages of small size, high efficiency and no dependence on conversion structure, and has broad application prospects in the industrial field. The mechanical spring used in traditional LOM can provide energy storage and resonant frequency, but it also increases the mass of the entire moving parts and the volume of the motor, reducing the compactness of the structure; and the mechanical spring will also have problems such as friction, material fatigue and failure during repeated stretching and compression. Due to the many problems of traditional mechanical springs, in recent years, springless linear oscillation motors have been developed at home and abroad. The principle is to use the restoring force between the permanent magnet of the mover and the stator core to form a magnetic equivalent spring, omitting the mechanical spring structure, and getting good solutions to the problems of structural complexity, compactness and friction fatigue. The analysis of the motor restoring force is crucial to the determination of the motor resonance point, and its accuracy will affect the operating efficiency of the motor. Therefore, it is of great significance to study an analysis method of the equivalent restoring force of a springless linear oscillation motor.

[0003] During the reciprocating motion of a traditional linear oscillation motor, there is a linear relationship between the restoring force provided by the mechanical spring and the position of the mover, which conforms to Hooke's law. However, the equivalent restoring force provided by the springless linear oscillation motor is provided by the magnetic force between the stator and the mover. Although the equivalent restoring force of the motor in the no-load state has a linear relationship with the mover position similar to that of a mechanical spring, when the current is passed through the winding, it will affect the distribution of the spatial magnetic field, thereby affecting the magnetic attraction between the stator and the mover. Therefore, if the restoring force of the motor in the no-load state is simply calculated, the operating resonance point is calculated using the relationship curve between the restoring force and the mover position obtained in the no-load state, which is obviously inaccurate and can easily lead to low operating efficiency of the motor. Therefore, in order to determine the operating resonance point of the springless linear oscillation motor, there is an urgent need for an analysis method that can take into account the influence of the winding current on the equivalent restoring force when the motor is running under load. Summary of the invention

[0004] In view of the above defects or improvement needs of the prior art, the present invention provides an equivalent restoring force analysis method and system for a springless linear oscillation motor, which is used to solve the technical problem that the prior art cannot accurately analyze the equivalent restoring force of the motor when the springless linear oscillation motor is in a load operation state.

[0005] In order to achieve the above object, in a first aspect, the present invention provides an equivalent restoring force analysis method of a springless linear oscillation motor, comprising:

[0006] S1. Based on the actual position and movement direction of the mover in the springless linear oscillation motor, calculate the winding current when the motor runs at the resonance point;

[0007] S2, setting the position and movement direction of the mover in the electromagnetic finite element model of the springless linear oscillation motor to the current actual position and movement direction of the mover, and applying the above winding current as winding current excitation to the electromagnetic finite element model, solving the electromagnetic finite element model, and obtaining the magnetic permeability distribution of the ferromagnetic material inside the motor under the winding current excitation;

[0008] S3. Keep the position and movement direction of the mover in the electromagnetic finite element model unchanged, import the magnetic permeability distribution of the ferromagnetic material inside the motor under the excitation of the winding current into the electromagnetic finite element model, and after removing the winding current excitation, solve the electromagnetic finite element model to obtain the magnetic density distribution of the ferromagnetic material inside the motor after removing the winding current excitation and the magnetic density distribution of the air gap space corresponding to the mover, and then obtain the current equivalent restoring force of the motor.

[0009] Further preferably, the current equivalent restoring force of the motor is:

[0010]

[0011] Where J is the air gap space corresponding to the mover; B Pi,j is the magnetic flux density at the jth position in the air gap space corresponding to the mover; μ 0 is the vacuum permeability; δ j is the length of the jth position in the air gap space corresponding to the mover in the vertical motion direction; K is the ferromagnetic material space inside the motor; B Pi,k is the magnetic flux density at the kth position of the ferromagnetic material inside the motor after the winding current excitation is removed; μ k is the magnetic permeability of the ferromagnetic material at the kth position inside the motor under the excitation of the winding current; δ k is the length of the ferromagnetic material at the kth position in the vertical direction of motion inside the motor; l stack is the axial length of the motor.

[0012] Further preferably, the winding current of the motor when it runs at the resonance point is:

[0013]

[0014] Among them, I m is the amplitude of the motor working current; x m is the maximum positive and negative stroke of the mover; x and are the actual position and direction of motion of the mover respectively; t represents time.

[0015] Further preferably, the electromagnetic finite element model of the springless linear oscillation motor is modeled using Ansys finite element simulation software.

[0016] Further preferably, the ferromagnetic material inside the motor includes: ferromagnetic material of the stator and ferromagnetic material of the mover.

[0017] In a second aspect, the present invention provides an equivalent restoring force analysis system for a springless linear oscillation motor, comprising: a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, it executes the equivalent restoring force analysis method for the springless linear oscillation motor provided in the first aspect of the present invention.

[0018] In a third aspect, the present invention provides a motor system, comprising: a control module and a springless linear oscillation motor;

[0019] The control module is used to obtain the current actual position and movement direction of the mover in the springless linear oscillation motor in real time, and execute the equivalent restoring force analysis method of the springless linear oscillation motor provided in the first aspect of the present invention to obtain the current equivalent restoring force of the motor, and calculate the current resonant frequency of the motor based on the current equivalent restoring force of the motor, thereby controlling the motor to operate at the current resonant frequency.

[0020] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects:

[0021] 1. The present invention provides an equivalent restoring force analysis method for a springless linear oscillation motor. Considering the saturation characteristics of ferromagnetic materials, when current is passed through the winding, it will affect the distribution of the spatial magnetic field, thereby affecting the magnetic attraction between the stator and the mover. First, the electromagnetic finite element model of the springless linear oscillation motor is applied with winding current excitation, and the magnetic permeability distribution of the ferromagnetic material inside the motor under the winding current excitation is obtained by solving; then the magnetic permeability distribution of the ferromagnetic material inside the motor under the winding current excitation is introduced into the electromagnetic finite element model, and after removing the winding current excitation, the current electromagnetic finite element model is solved to obtain the magnetic density distribution of the ferromagnetic material inside the motor after removing the winding current excitation and the magnetic density distribution of the air gap space corresponding to the mover, thereby obtaining the current equivalent restoring force of the motor. The present invention fully considers the influence of winding current excitation, and realizes the effect of coupling magnetic field separation through the above process, and can accurately analyze the equivalent restoring force of the motor under the load operation state of the springless linear oscillation motor.

[0022] 2. The present invention provides a motor system, in which the control module obtains accurate motor equivalent restoring force based on the equivalent restoring force analysis method provided by the present invention, and then can accurately calculate the resonant frequency of the motor, thereby achieving precise control of the motor and improving the motor operation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A flow chart of an equivalent restoring force analysis method for a springless linear oscillation motor provided by an embodiment of the present invention;

[0024] Figure 2 A schematic diagram of a curve showing the relationship between the position of a mover and the winding current provided in an embodiment of the present invention;

[0025] Figure 3 A finite element model diagram of a springless linear oscillation motor provided in an embodiment of the present invention;

[0026] Figure 4 A curve diagram showing the relationship between the equivalent restoring force and the position of the mover of the springless linear oscillation motor provided in an embodiment of the present invention in a no-load state and a loaded operating state respectively. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0028] In order to achieve the above objectives, in a first aspect, the present invention provides an equivalent restoring force analysis method for a springless linear oscillation motor, such as Figure 1 As shown, including:

[0029] S1. Based on the actual position and movement direction of the mover in the springless linear oscillation motor, calculate the winding current when the motor runs at the resonance point;

[0030] In order to make the motor run at the resonance point, the stroke (position) and movement direction of the mover determine the magnitude and direction of the current flowing into the winding. Specifically, taking the balance position of the mover as the coordinate origin, when the mover moves in the positive direction to a certain position x, the relationship curve between the mover position and the winding current is as follows: Figure 2 In an optional implementation, the winding current of the motor when it runs at the resonance point is:

[0031]

[0032] Among them, I m is the amplitude of the motor working current; xm is the maximum positive and negative stroke of the mover; x and are the actual position and direction of motion of the mover respectively; t represents time.

[0033] S2. The position and movement direction of the mover in the electromagnetic finite element model of the springless linear oscillation motor are set to the current actual position and movement direction of the mover, and the above winding current is applied to the electromagnetic finite element model as the winding current excitation. At this time, permanent magnet excitation and winding current excitation exist in the motor at the same time. The current electromagnetic finite element model is solved to obtain the magnetic permeability distribution of the ferromagnetic material inside the motor under the winding current excitation; wherein, the ferromagnetic material inside the motor includes: the ferromagnetic material of the stator and the ferromagnetic material of the mover.

[0034] Preferably, in an optional implementation, the electromagnetic finite element model of the springless linear oscillation motor is pre-modeled using Ansys finite element simulation software. After the electromagnetic finite element model is established, it is initialized, and the initialization content includes the motor position, the amplitude and frequency of the winding current, and the solver and other related simulation parameters. Specifically, the finite element model of the springless linear oscillation motor is shown in FIG. Figure 3 As shown, it includes: a stator core 1, a main (armature) winding 2, a permanent magnet 3 at the center of the mover and permanent magnets 4 at both sides of the mover.

[0035] S3. Keep the position and movement direction of the mover in the electromagnetic finite element model unchanged, which is still the current actual position and movement direction of the mover. Import the magnetic permeability distribution of the ferromagnetic material inside the motor under the winding current excitation into the electromagnetic finite element model, and remove the winding current excitation. At this time, there is permanent magnet excitation in the motor as well as the influence of winding current excitation. Solve the current electromagnetic finite element model to obtain the magnetic density distribution of the ferromagnetic material inside the motor after removing the winding current excitation and the magnetic density distribution of the air gap space corresponding to the mover, and then obtain the current equivalent restoring force of the motor.

[0036] There is a magnetic pulling force between the mover core and the mover permanent magnet, which is the equivalent restoring force at this time; in an optional implementation manner, the current equivalent restoring force of the motor is:

[0037]

[0038] Among them, J is the air gap space corresponding to the mover; B Pi,j is the magnetic flux density at the jth position in the air gap space corresponding to the mover; μ 0 is the vacuum permeability; δ j is the length of the jth position in the air gap space corresponding to the mover in the vertical motion direction; K is the ferromagnetic material space inside the motor; B Pi,k is the magnetic flux density at the kth position of the ferromagnetic material inside the motor after the winding current excitation is removed; μk is the magnetic permeability of the ferromagnetic material at the kth position inside the motor under the excitation of the winding current; δ k is the length of the ferromagnetic material at the kth position in the vertical direction of motion inside the motor; l stack is the axial length of the motor.

[0039] In order to further illustrate the equivalent restoring force analysis method of the springless linear oscillation motor provided by the present invention, the present invention samples multiple positions within the range of the mover motion cycle to obtain the equivalent restoring force results of the springless linear oscillation motor in the no-load state and the loaded running state when the mover is at different positions. Figure 4 As shown. Figure 4 It can be seen that the equivalent restoring force of the springless linear oscillation motor in the no-load state and the loaded operating state is not much different in the position section close to the topological midpoint, and the difference gradually increases near the end of the mover stroke.

[0040] In general, the present invention provides an analysis method for the equivalent restoring force of a springless linear oscillation motor. Through the electromagnetic finite element model of the springless linear oscillation motor, the equivalent restoring force of the motor when the mover is in different positions and movement directions can be accurately calculated on the basis of considering the load effect of the springless linear oscillation motor, thereby obtaining the corresponding operating resonance point, providing a basis for optimal control of the motor.

[0041] The present invention fully considers the saturation characteristics of the magnetization curve of the ferromagnetic material, and can more accurately reflect the change of the internal magnetic permeability of the motor under the load state, so that the method can improve the accuracy when calculating the equivalent restoring force of the springless linear oscillation motor.

[0042] The equivalent restoring force is one of the important indicators for evaluating the performance of a springless linear oscillation motor. The analysis method of the equivalent restoring force provided by the present invention is more in line with the actual operating conditions of the motor, can more accurately evaluate the performance of the motor, and provide strong support for the optimal control of the motor.

[0043] In a second aspect, the present invention provides an equivalent restoring force analysis system for a springless linear oscillation motor, comprising: a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, it executes the equivalent restoring force analysis method for the springless linear oscillation motor provided in the first aspect of the present invention.

[0044] The related technical solution is the same as the equivalent restoring force analysis method of the springless linear oscillation motor provided in the first aspect of the present invention, and will not be elaborated here.

[0045] In a third aspect, the present invention provides a motor system, comprising: a control module and a springless linear oscillation motor;

[0046] The control module is used to obtain the current actual position and movement direction of the mover in the springless linear oscillation motor in real time, and execute the equivalent restoring force analysis method of the springless linear oscillation motor provided in the first aspect of the present invention to obtain the current equivalent restoring force of the motor, and calculate the current resonant frequency of the motor based on the current equivalent restoring force of the motor, thereby controlling the motor to operate at the current resonant frequency.

[0047] The present invention can take into account the saturation characteristics of ferromagnetic materials, can accurately calculate the equivalent restoring force in the magnetic field when the load is running, achieve the effect of coupling magnetic field separation, and obtain a more accurate relationship between the equivalent restoring force and the position of the mover of the springless linear motor, thereby calculating a resonance point that is more in line with the actual operation of the motor, and better providing a basis for the reasonable design of the motor and the analysis of the dynamic behavior of the motor.

[0048] The related technical solution is the same as the equivalent restoring force analysis method of the springless linear oscillation motor provided in the first aspect of the present invention, and will not be elaborated here.

[0049] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for analyzing the equivalent restoring force of a springless linear oscillation motor, characterized in that: include: S1. Based on the actual position and movement direction of the mover in the springless linear oscillation motor, calculate the winding current when the motor runs at the resonance point; S2, setting the position and movement direction of the mover in the electromagnetic finite element model of the springless linear oscillation motor to the current actual position and movement direction of the mover, and applying the winding current as the winding current excitation to the electromagnetic finite element model, solving the electromagnetic finite element model to obtain the magnetic permeability distribution of the ferromagnetic material inside the motor under the winding current excitation; S3. Keeping the position and movement direction of the mover in the electromagnetic finite element model unchanged, the magnetic permeability distribution of the ferromagnetic material inside the motor under the excitation of the winding current is introduced into the electromagnetic finite element model. After removing the winding current excitation, the electromagnetic finite element model is solved to obtain the magnetic density distribution of the ferromagnetic material inside the motor after removing the winding current excitation and the magnetic density distribution of the air gap space corresponding to the mover, and then the current equivalent restoring force of the motor is obtained.

2. The equivalent restoring force analysis method according to claim 1, characterized in that: The current equivalent restoring force of the motor is: Among them, J is the air gap space corresponding to the mover; B Pi,j is the magnetic flux density at the jth position in the air gap space corresponding to the mover; μ0 is the vacuum magnetic permeability; δ j is the length of the jth position in the air gap space corresponding to the mover in the vertical motion direction; K is the ferromagnetic material space inside the motor; B Pi,k is the magnetic flux density at the kth position of the ferromagnetic material inside the motor after the winding current excitation is removed; μ k is the magnetic permeability of the ferromagnetic material at the kth position inside the motor under the excitation of the winding current; δ k is the length of the ferromagnetic material at the kth position in the vertical direction of motion inside the motor; l stack is the axial length of the motor.

3. The equivalent restoring force analysis method according to claim 1, characterized in that: The winding current is: Among them, I m is the amplitude of the motor working current; x m is the maximum positive and negative stroke of the mover; x and are the actual position and direction of motion of the mover respectively; t represents time.

4. The equivalent restoring force analysis method according to any one of claims 1 to 3, characterized in that: The electromagnetic finite element model is modeled using Ansys finite element simulation software.

5. The equivalent restoring force analysis method according to any one of claims 1 to 3, characterized in that: The ferromagnetic material inside the motor includes: ferromagnetic material of the stator and ferromagnetic material of the mover.

6. An equivalent restoring force analysis system for a springless linear oscillation motor, characterized in that: include: A memory and a processor, wherein the memory stores a computer program, and the processor executes the equivalent restoring force analysis method according to any one of claims 1 to 5 when executing the computer program.

7. A motor system, characterized in that: include: Control module and springless linear oscillation motor; The control module is used to obtain the current actual position and movement direction of the mover in the springless linear oscillation motor in real time, and execute the equivalent restoring force analysis method described in any one of claims 1-5 to obtain the current equivalent restoring force of the motor, and calculate the current resonant frequency of the motor based on the current equivalent restoring force of the motor, thereby controlling the motor to operate at the current resonant frequency.

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