An equivalent restoring force analysis method and system for a springless linear oscillation motor

Abstract

The application discloses a kind of equivalent restoring force analysis method and system of springless linear oscillation motor, belong to electromagnetic field analysis calculation technical field;Considering the saturation characteristics of ferromagnetic material, first the electromagnetic finite element model of springless linear oscillation motor is applied winding current excitation, the permeability distribution of ferromagnetic material in motor under winding current excitation is solved, then the permeability distribution of ferromagnetic material in motor under winding current excitation is introduced into electromagnetic finite element model, remove winding current excitation, solve the current electromagnetic finite element model, obtain the magnetic density distribution of ferromagnetic material in motor after removing winding current excitation and the magnetic density distribution of mover corresponding air gap space, and then obtain the current equivalent restoring force of motor.The application fully considers the influence of winding current excitation, and realizes the effect of coupling magnetic field separation through the above process, can accurately analyze the equivalent restoring force of motor under the load running state of springless linear oscillation motor.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of electromagnetic field analysis and calculation, and more particularly relates to a method and system for analyzing equivalent restoring force of a springless linear oscillatory motor. BACKGROUND

[0002] Linear oscillatory motor (LOM) can directly realize the conversion of electrical energy and linear reciprocating mechanical energy, has the advantages of small size, high efficiency and independence of conversion structure, and has a wide application prospect in the industrial field. The mechanical spring used in the traditional LOM can provide energy storage and resonance frequency, but also increases the mass of the entire moving part and the size of the motor, reducing the compactness of the structure. Moreover, mechanical springs 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 oscillatory motors have been developed at home and abroad. The principle is to use the restoring force between the mover permanent magnet and the stator core to form a magnetic equivalent spring, eliminating the mechanical spring structure, and solving the problems of structure complexity, compactness and friction fatigue. The analysis of the restoring force of the motor is crucial for the determination of the resonance point of the motor, and its accuracy will affect the operating efficiency of the motor. Therefore, it is of great significance to study an analysis method for the equivalent restoring force of a springless linear oscillatory motor.

[0003] During the reciprocating motion of the traditional linear oscillatory motor, the restoring force provided by the mechanical spring has a linear relationship with the position of the mover, i.e. it conforms to Hooke's law. However, the equivalent restoring force provided by the springless linear oscillatory motor is provided by the magnetic force between the stator and the mover. Although the equivalent restoring force of the motor under no-load condition has a linear relationship with the position of the mover similar to that of the mechanical spring, the distribution of the space magnetic field will be affected when the winding is energized, thereby affecting the magnetic attraction force between the stator and the mover. Therefore, if only the restoring force under no-load condition is calculated, and the relationship curve between the restoring force and the position of the mover under no-load condition is used to calculate the operating resonance point, it is obviously inaccurate and easy to make the motor operate at a low efficiency. Therefore, in order to determine the operating resonance point of the springless linear oscillatory motor, an analysis method is needed that can consider the effect of the winding current on the equivalent restoring force when the motor is under load. SUMMARY

[0004] In view of the above defects or improvement needs of the prior art, the present application provides a method and system for analyzing the equivalent restoring force of a springless linear oscillatory motor, to solve the technical problem that the prior art cannot accurately analyze the equivalent restoring force of the springless linear oscillatory motor under load operation.

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

[0006] S1, based on the current actual position and motion direction of the mover in the springless linear oscillation motor, calculating the winding current when the motor operates at the resonance point;

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

[0008] S3, keeping the mover position and motion direction in the electromagnetic finite element model unchanged, introducing the permeability distribution of the ferromagnetic material inside the motor under winding current excitation into the electromagnetic finite element model, removing the winding current excitation, and solving the electromagnetic finite element model to obtain the magnetic flux density distribution of the ferromagnetic material inside the motor after removing the winding current excitation and the magnetic flux density distribution of the corresponding air gap space of the mover, and further obtaining the current equivalent restoring force of the motor.

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

[0010]

[0011] Wherein, 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 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 space of the ferromagnetic material inside the motor; B Pi,k is the magnetic flux density at the kth position of the ferromagnetic material inside the motor after removing the winding current excitation; μ k is the permeability of the kth position of the ferromagnetic material inside the motor under winding current excitation; δ k is the length of the kth position of the ferromagnetic material inside the motor in the vertical motion direction; l stack is the axial length of the motor.

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

[0013]

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

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

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

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

[0018] In a third aspect, the present application 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 motion direction of the mover in the springless linear oscillation motor in real time, execute the equivalent restoring force analysis method of the springless linear oscillation motor provided in the first aspect of the present application, obtain the current equivalent restoring force of the motor, calculate the current resonant frequency of the motor based on the current equivalent restoring force of the motor, and then control the motor to operate at the current resonant frequency.

[0020] Overall, the above technical solutions conceived by the present application can achieve the following beneficial effects:

[0021] 1. The present application provides an equivalent restoring force analysis method of a springless linear oscillation motor, which takes into account the saturation characteristics of ferromagnetic materials. When the winding is energized, it will affect the distribution of the space magnetic field, thereby affecting the magnetic attraction between the stator and the mover. First, the winding current excitation is applied to the electromagnetic finite element model of the springless linear oscillation motor, and the permeability distribution of the internal ferromagnetic material of the motor under winding current excitation is obtained. Then, the permeability distribution of the internal ferromagnetic material of the motor under winding current excitation is introduced into the electromagnetic finite element model, and the current electromagnetic finite element model is solved after removing the winding current excitation, to obtain the magnetic flux density distribution of the internal ferromagnetic material of the motor and the magnetic flux density distribution of the corresponding air gap space of the mover after removing the winding current excitation, and then the current equivalent restoring force of the motor is obtained. The present application fully considers the influence of winding current excitation and realizes the effect of coupling magnetic field separation through the above process, which can accurately analyze the equivalent restoring force of the motor under the load running state of the springless linear oscillation motor.

[0022] 2. The control module in the motor system provided by the present application can accurately calculate the resonant frequency of the motor based on the accurate equivalent restoring force of the motor obtained by the equivalent restoring force analysis method provided by the present application, thereby realizing precise control of the motor and improving the operating efficiency of the motor. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 A flow chart of an equivalent restoring force analysis method of a springless linear oscillation motor provided by an embodiment of the present application is shown in the figure.

[0024] Figure 2 A curve diagram of the relationship between the mover position and the winding current provided by an embodiment of the present application is shown in the figure.

[0025] Figure 3 A finite element model diagram of a springless linear oscillation motor provided by an embodiment of the present application is shown in the figure.

[0026] Figure 4 A curve diagram of the relationship between the equivalent restoring force and the mover position of a springless linear oscillation motor provided by an embodiment of the present application under no-load state and under load operation state respectively. DETAILED DESCRIPTION

[0027] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application. In addition, the technical features involved in each embodiment of the present application 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-mentioned purpose, in a first aspect, the present application provides an equivalent restoring force analysis method of a springless linear oscillation motor, as shown in the figure, comprising: Figure 1

[0029] S1, based on the current actual position and motion direction of the mover in the springless linear oscillation motor, the winding current when the motor operates at the resonance point is calculated;

[0030] In order to make the motor operate at the resonance point, the stroke (position) and motion direction of the mover determine the size and direction of the winding current. Specifically, taking the balance position of the mover as the coordinate origin, when the mover moves to a position x in the positive direction, the relationship between the mover position and the winding current is shown in the figure. In an alternative embodiment, the winding current when the motor operates at the resonance point is: Figure 2

[0031]

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

[0033] ​​S2, set the mover position and motion direction in the electromagnetic finite element model of the springless linear oscillation motor to the actual position and motion direction of the mover at present, and apply the winding current as above to the electromagnetic finite element model as winding current excitation, at this time, the motor simultaneously exists permanent magnet excitation and winding current excitation, solve the current electromagnetic finite element model to obtain the permeability distribution of the ferromagnetic material in the motor under winding current excitation; wherein the ferromagnetic material in the motor includes: the ferromagnetic material of the stator and the ferromagnetic material of the mover.

[0034] Preferably, in an optional embodiment, the electromagnetic finite element model of the springless linear oscillation motor is obtained by pre-modeling with Ansys finite element simulation software. After the electromagnetic finite element model is established, it is initialized, and the initialization content includes the mover position, the amplitude and frequency of the winding current, and the related simulation parameters such as the solver. Specifically, the finite element model diagram of the springless linear oscillation motor is shown in Figure 3 , which includes: stator core 1, main (armature) winding 2, mover center permanent magnet 3 and mover two side permanent magnets 4.

[0035] S3, keep the mover position and motion direction in the electromagnetic finite element model unchanged, still the actual position and motion direction of the mover at present, import the permeability distribution of the ferromagnetic material in the motor under winding current excitation into the electromagnetic finite element model, remove the winding current excitation, at this time, the motor exists permanent magnet excitation and the influence of winding current excitation, solve the current electromagnetic finite element model to obtain the magnetic flux density distribution of the ferromagnetic material in the motor after removing the winding current excitation and the magnetic flux density distribution of the corresponding air gap space of the mover, and further obtain the current equivalent restoring force of the motor.

[0036] There will be a magnetic pull between the mover core and the mover permanent magnet, that is, the equivalent restoring force at this time; in an optional embodiment, the current equivalent restoring force of the motor is:

[0037]

[0038] Wherein, J is the corresponding air gap space of the mover; B Pi,j is the magnetic flux density at the jth position in the corresponding air gap space of the mover; μ0 is the vacuum permeability; δ j is the length in the vertical motion direction of the jth position in the corresponding air gap space of the mover; K is the space of the ferromagnetic material in the motor; B Pi,k is the magnetic flux density at the kth position of the ferromagnetic material in the motor after removing the winding current excitation; μ k is the permeability at the kth position of the ferromagnetic material in the motor under winding current excitation; δ k is the length in the vertical motion direction of the kth position of the ferromagnetic material in the motor; l stack is the axial length of the motor.

[0039] To further illustrate the equivalent restoring force analysis method for the springless linear oscillating motor provided by this invention, this invention samples multiple positions within the stroke range of the mover's motion cycle to obtain the equivalent restoring force results of the springless linear oscillating motor under no-load and load operating conditions when the mover is in different positions. Specifically, as follows... Figure 4 As shown. From Figure 4 It can be seen that the equivalent restoring force of the springless linear oscillating motor is not much different in the position segment near the midpoint of the topology under no-load and load operation conditions, but the difference gradually increases near the end of the mover stroke.

[0040] In summary, this invention provides an analysis method for the equivalent restoring force of a springless linear oscillating motor. By using the electromagnetic finite element model of the springless linear oscillating motor, the equivalent restoring force of the motor when the mover is in different positions and directions of motion can be accurately calculated, taking into account the load effect of the springless linear oscillating motor. This allows for the determination of the corresponding operating resonance point, providing a basis for optimal control of the motor.

[0041] This invention fully considers the saturation characteristics of the magnetization curve of ferromagnetic materials, and can more accurately reflect the change of the internal permeability of the motor under load, so that the method can improve the accuracy when calculating the equivalent restoring force of a springless linear oscillating motor.

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

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

[0044] The relevant technical solutions are the same as the equivalent restoring force analysis method for the springless linear oscillating motor provided in the first aspect of this invention, and will not be described in detail here.

[0045] Thirdly, the present invention provides a motor system, comprising: a control module and a springless linear oscillating motor;

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

[0047] The present application can consider the saturation characteristics of the ferromagnetic material, accurately calculate the equivalent restoring force existing in the magnetic field during load operation, realize the effect of separating the coupled magnetic field, obtain the more accurate relationship between the equivalent restoring force of the springless linear motor and the position of the mover, and thus calculate the resonant point more in line with the actual operation of the motor, better provide the basis for reasonably designing the motor and analyzing the dynamic behavior of the motor.

[0048] The related technical solution is the equivalent restoring force analysis method of the springless linear oscillation motor provided in the first aspect of the present application, which is not described here.

[0049] Those skilled in the art can easily understand that the above description is only a preferred embodiment of the present application, and is not used to limit the present application, and any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for analyzing equivalent restoring force of a springless linear oscillation motor, characterized by, The method comprises the following steps: S1. Based on the current actual position and motion direction of the mover in the springless linear oscillation motor, the winding current when the motor operates at the resonance point is calculated; S2. The position and motion direction of the mover in the electromagnetic finite element model of the springless linear oscillation motor are set to the current actual position and motion direction of the mover, the winding current is applied as winding current excitation in the electromagnetic finite element model, and the electromagnetic finite element model is solved to obtain the permeability distribution of the ferromagnetic material in the motor under the winding current excitation; S3. The position and motion direction of the mover in the electromagnetic finite element model are kept unchanged, the permeability distribution of the ferromagnetic material in the motor under the winding current excitation is introduced into the electromagnetic finite element model, the electromagnetic finite element model is solved after removing the winding current excitation, the magnetic flux density distribution of the ferromagnetic material in the motor and the magnetic flux density distribution of the corresponding air gap space of the mover after removing the winding current excitation are obtained, and then the current equivalent restoring force of the motor is obtained. The current equivalent restoring force of the motor is: wherein, J is the air gap space corresponding to the mover; is the magnetic flux density at the i-th position in the air gap space corresponding to the mover; j is the vacuum permeability; is the length in the vertical motion direction of the i-th position in the air gap space corresponding to the mover; j K is the space of the ferromagnetic material inside the motor; is the magnetic flux density at the i-th position of the ferromagnetic material inside the motor after removing the excitation of the winding current; k is the permeability at the i-th position of the ferromagnetic material inside the motor under the excitation of the winding current; k is the length in the vertical motion direction of the i-th position of the ferromagnetic material inside the motor; k is the axial length of the motor.​​​​​ 2. The equivalent restoring force analysis method according to claim 1, characterized by, The winding current is: wherein, is the amplitude of the motor operating current; is the positive or negative maximum stroke of the mover motion; x and are the current actual position and direction of motion of the mover, respectively; t denotes time.

3. The equivalent restoring force analysis method according to any one of claims 1-2, characterized in that, The electromagnetic finite element model is obtained by modeling using Ansys finite element simulation software.

4. The equivalent restoring force analysis method according to any one of claims 1 to 2, characterized by, The ferromagnetic material in the motor includes the ferromagnetic material of the stator and the ferromagnetic material of the mover.

5. An equivalent restoring force analysis system for a springless linear oscillatory motor, characterized by, The method comprises the following steps: A memory and a processor, the memory stores a computer program, and the processor executes the computer program to execute the equivalent restoring force analysis method of any one of claims 1-4.

6. An electric motor system characterized by The method comprises the following steps: A control module and a springless linear oscillation motor; The control module is used for acquiring the current actual position and motion direction of the mover in the springless linear oscillation motor in real time, executing the equivalent restoring force analysis method of any one of claims 1-4 to obtain the current equivalent restoring force of the motor, calculating the current resonance frequency of the motor based on the current equivalent restoring force of the motor, and then controlling the motor to operate at the current resonance frequency.

Images