JP2996586B2 - Calculation method of mutual force of motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for calculating a mutual force of a motor, which calculates the mutual force of the motors.

[0002]

2. Description of the Related Art In performing a numerical analysis of a motor, the basic form of the motor can be considered as two coils that mutually affect each other. The method of obtaining the force acting between the two coils can be roughly classified into the following three methods, each of which is appropriately adopted. In other words, there are two methods: direct force (Lorentz force etc.), electromagnetic field stress distribution (Maxwell's stress method), and energy conservation law (energy displacement method).

[0003]

However, in the conventional calculation method, it is necessary to perform a numerical calculation every time the state or condition of the magnet or the coil changes, regardless of the above-mentioned method. For example, in order to obtain a torque waveform for one rotation of the motor, the relative position of one rotation is divided into several tens, and the calculation cannot be performed unless numerical calculations are performed for the number of times. The shape (thickness, width, length, shape, etc.), strength,
In order to find the mutual force when the magnetization waveform (number of magnetic poles, shape, etc.) changes, it was not possible to obtain the mutual force unless numerical calculations were performed for the number of times of change. The time required for the numerical calculation at this time depends on the number of requests and the capacity of the computer.
It is not unusual for it to take several hours each time. Therefore, for example, it is necessary to calculate several tens of times just to obtain the torque waveform of one rotation, and it is required to reduce the calculation time.

[0004] In view of such circumstances, an object of the present invention is to provide a motor mutual force calculation method capable of greatly shortening a calculation time for obtaining a motor mutual force.

[0005]

According to a first aspect of the present invention, a coil and a magnet, or any one of them, are arranged so as to be relatively movable and utilize mutual forces. In the method of calculating the mutual force of the motor described above, the magnetic flux density distribution of the coil or magnet on one side is obtained only once, and the mutual force, back electromotive force, effective magnetic flux, etc., in any state and condition of the magnet on the other side are calculated. It has a configuration that is determined by utilizing the laws of properties and energy conservation.

According to a second aspect of the present invention, there is provided a method for calculating a mutual force of a motor in which a coil and a magnet or one of them is arranged so as to be relatively movable and the mutual force is utilized. Once the magnetic flux density distribution by the coil or magnet on the side is determined once, the mutual force, back electromotive force, effective magnetic flux, etc. in any state and condition of the coil with the coreless or slotless structure on the other side, the properties of mutual inductance and energy conservation The structure is designed to be obtained by utilizing the law of

As described above, the present invention relates to a method for determining a mutual force in a motor based on the properties of mutual inductance and the law of conservation of energy. Hereinafter, the description will be made. In general, when the amount of stored energy changes in a state where there is no external energy transfer, some work has been performed according to the law of energy conservation. That is, the two objects are now relatively d
Assuming that the energy changes dW by moving x, dW = F · dx, that is, the force of F = dW / dx has been applied. Such a method of obtaining a force from an energy displacement is called an energy displacement method (or a virtual displacement method).

[0008] By the way, the magnetic energy held by the motor can be represented by two forms due to the difference in the form. One is a state (part) where magnetic energy is actually distributed, and the other is a state (part) where magnetic energy is generated and held. The former can be obtained by adding all the magnetic energies (H.B / 2) of the affected area, but it is actually difficult because it covers a wide range. On the other hand, the latter concentrates on a certain part from the form and can be easily obtained. The present invention
This is a method for easily calculating mutual forces in various states and conditions from the magnetic energy obtained by the latter.

[0009] The motor of the basic form initially, can be considered as two coils mutually affect each other, to represent the magnetic energy W of the two coils is generated and ^{_{retained, W = L J I J 2}} /2 + _{MI J I C + L C I} C 2/2 = Φ J I J / 2 + Φ MJ I C + Φ C I C / 2 = Φ J m / 2 + Φ MJ I C + Φ C I C / 2 = Φ _J m / 2 + Φ _MC m + Φ _C I _C / 2. Where L is self-inductance, I is current, M
Is a mutual inductance, Φ is a magnetic flux, and m is a magnetic moment (magnetization). The first term in each equation is the energy held (generated) by the magnet itself, and the third term is held by the armature coil itself ( Energy), and the second term is 2
The energy that two coils (or magnets) interact with and hold (generate).

Next, equations of various electromagnetic forces in the motor will be expressed based on the energy displacement method. There is no external energy transfer, and I and m in the above magnetic energy formula
Is fixed, the difference between the energies caused by the relative movement of the two coils by dx is dW. From dW = F · dx, the force F (the total force T) acting at that time is obtained. ) Is represented by the following equation. F = dW / dx = (dΦ _J / dx) · (m / 2) + (dΦ _MJ / dx) · I _C + (dΦ _C / dx) · (I _C / 2) = (dΦ _J / dx) · (m / 2) + (dΦ _MC / dx) ・ m + (dΦ _C / dx) ・ (I _C / 2)

The first term in the above equation is the force generated by the magnet itself, that is, cogging. The second term is a force due to interaction between the magnet and the coil (mutual force), that is, a driving force of a normal motor. The third term is a force generated by the coil itself, that is, an attractive force by the electromagnet.

[0012] Mutual force from this equation the second term, the difference between the per relative position flux ([Phi _MJ or [Phi _MC), it can be seen that the determined by match over I _C or m. According to the conventional manner, the second movement depends on the relative movement of both side members (hereinafter referred to as A-side member and B-side member) and the state and condition of the magnet (or coil) as the other B-side member. Since the values of the elements that make up the terms change, it was necessary to perform the numerical calculations the same number of times as the changes. However, considering the case of an actual motor, even if the A-side member and the B-side member on both sides move relative to each other, or the state and condition of the magnet (or coil) as the B-side member on the other side change. In most cases, the magnetic flux density distribution itself generated by the magnet (or coil) as the one A-side member does not change.

For example, in the case of relative movement, the magnetic flux intersecting with the magnet (or coil) as the B-side member on the other side changes with the relative movement, but the magnetic flux density distribution itself is merely moving relatively. In many cases, the structure does not change.
Also, a magnet (or coil) as the other B-side member
If the shape, position, size, strength, etc. of the
The intersecting magnetic flux varies accordingly, but the magnetic flux density distribution itself often remains unchanged. In the case of the above structure, since the magnetic flux density distribution itself does not change, once the magnetic flux density distribution is obtained and stored by numerical calculation, it is not necessary to perform the numerical calculation each time to obtain the magnetic flux density distribution. Also extracts the necessary data of the stored magnetic flux density distribution,
It can be seen that the mutual component of the magnetic energy can be obtained by multiplying m (or Ic) accordingly. That is, m (or Ic) corresponding to each change
Is generated and multiplied by the stored magnetic flux density distribution to determine the mutual force.

[0014]

In the above means, conventionally, several tens of times,
The contents requiring the operation several hundred times are executed only by one numerical analysis and subsequent data processing, so that the operation time is greatly reduced. Specifically, according to the means of the present invention, the following can be performed by performing numerical analysis and data processing. First, once the magnetic flux density distribution by the magnet or the coil as the A-side member on one side is obtained, the mutual force and the back electromotive voltage in any state and condition of the magnet as the B-side member on the other side are obtained only by data processing. , An effective magnetic flux waveform and the like can be calculated. Here, all the states and conditions of the magnet are the shape (thickness, width, length, irregularities, etc.) of the magnet, the strength of the magnet, the magnetization waveform (sine, trapezoid, skew, number of magnetic poles, magnetization in the thickness direction). Distribution, etc.), and the mutual force is calculated by obtaining magnetic energy by adding the magnetic flux density distribution of one A-side member multiplied by the magnetization of the magnet. Normally, the magnetic body (yoke or the like) on the magnet side has a flat shape, and the magnetic flux density distribution generated by the A-side member does not change even if the A-side member on one side and the magnet side move relatively. In the case of such a structure, once the magnetic flux density distribution by the A-side member on one side is determined once, the mutual force in any state and condition on the magnet side can be changed simply by changing the magnetization distribution of the opposing magnet by data processing. Can be calculated.

More specifically, a temporary magnet element or a spatial point may be provided to determine a magnetic flux density distribution, and then multiplied by the magnetization of the magnet in a necessary state and condition. By rotating the magnetization distribution, a torque waveform for one rotation is obtained. If the calculation is performed while changing the magnetization distribution, any magnet strength and magnetization waveform such as skew magnetization can be obtained. If the range is changed, any thickness, width, length, shape ( Gap length, etc.).

Next, in the case of the normal coreless / slotless operation, the magnetic flux density distribution by the A-side member on one side does not change even if the relative position is moved. After that, the mutual force, back electromotive force,
Effective magnetic flux and the like can be calculated. Here, all states on the coil side refer to the shape (shape, thickness, width,
The size refers to any state on the coil side, such as the size of the coil, the position of the coil, and the condition refers to a condition to be obtained such as a torque waveform for one rotation, a back electromotive waveform, a torque constant, a back electromotive constant, and an effective magnetic flux.

Normally, in the case of the coreless / slotless type, the magnetic material (core / yoke, etc.) on the coil side has a flat shape, and even if the A-side member and the B-side member on one side move relatively. The magnetic flux density distribution generated by the A-side member does not change.
For this reason, once the magnetic flux density distribution of the A-side member is obtained, the mutual force in any state and condition on the coil side can be calculated by simply changing the state and condition on the coil side by data processing. .

More specifically, a temporary coil element or a spatial point may be provided to determine a magnetic flux density distribution, a coil having an arbitrary position and shape may be set therein, and an effective magnetic flux may be determined. Then, by rotating the coil condition, a torque waveform for one rotation is obtained. If the calculation is performed while changing the position and shape conditions of the coil, the mutual force in every state on the coil side is calculated.

[0019]

Embodiments of the present invention will be described below in detail. In the embodiment shown in FIG. 1, the components are first assembled in a step. This assembling of the elements is for assembling the fixed elements necessary for the numerical analysis, and there is no need to change the conditions and see the effect thereof.
That is, a magnet (or coil) as one A-side member
The components necessary for obtaining the magnetic flux density distribution are assembled. Further, a temporary element may be provided for directly obtaining the magnetic flux density. Regardless of the method of analysis at this time,
Any method can be used as long as the magnetic flux density distribution can be accurately obtained. For example, there are a finite element method, a boundary element method, a difference method, a magnetic moment method, and the like.

Next, in step 2, conditions are set for the fixed element as the A-side member on one side, such as the magnetization strength of the magnet, the magnitude of the current, etc., and then this calculation is executed in step 3. . In this calculation, the equation is solved to calculate the magnetic flux density distribution or the magnetic flux density of a specific part.
In the next step 4, the magnetic flux density distribution obtained in step 3 is stored.

Further, in step 5, B on the other side
The condition data of the magnet element or the coil element as the side member is created. Specifically, the condition data of the magnet element include the shape of the magnet (thickness, width, length, irregularities, etc.), the strength of the magnet (magnetization strength, etc.), the magnetization waveform (number of magnetic poles, sine
Magnetization waveform such as trapezoid, skew magnetization, magnetization distribution in thickness direction, etc.), magnet position (relative positional relationship between rotor and stator, etc.). The condition data of the coil element include a coil shape (coil shape, coil thickness, coil width, coil size, etc.), a coil position (relative positional relationship with respect to the magnet side, etc.), and a coil current (coil current). Number of turns,
Current flowing).

Next, in step 6, the above-described step 4
Is multiplied by the magnet magnetization distribution or the coil current distribution in Step 5, and the magnetic energy of the mutual component is calculated. Such an operation is
After the condition is changed as necessary (step 5), the process is repeated a plurality of times. The energy difference determined here is divided by the distance moved in the next step 7 to obtain a mutual force. Further, a back electromotive voltage, a torque constant, an effective magnetic flux, and the like are calculated as needed. The calculation at this time is repeated a plurality of times after the condition is changed as necessary (step 5).

Although the invention made by the inventor has been specifically described based on the embodiments, the present invention is not limited to the above-described embodiments, and can be variously modified without departing from the gist thereof. Needless to say.

[0024]

As described above, the method of calculating the mutual force of the motor according to the present invention incorporates the law of conservation of energy and the nature of the mutual inductance into the numerical analysis of the motor and applies the same to the coil and the magnet or the magnet that move relatively. Since the distribution of magnetic flux generated on one side in a combination of any one of these is obtained, and thereafter, the mutual force in all states and conditions on the other side is obtained only by data processing. The contents requiring multiple operations can be performed only by one numerical calculation and subsequent data processing. As a result, numerical analysis can be performed extremely efficiently, and the calculation time can be greatly reduced.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a calculation procedure in one embodiment of the present invention.

Claims (2)

(57) [Claims] 1. A method for calculating a mutual force of a motor in which a coil and a magnet or one of these members are arranged so as to be relatively movable to utilize a mutual force. Once the magnetic flux density distribution by the coil or magnet constituting one member of the one side is determined once, the mutual force and other necessary values of the magnet constituting the other side in all states and conditions are determined by the properties and energy of the mutual inductance. A method for calculating a mutual force of a motor, wherein the method is obtained by utilizing the law of conservation. 2. A method for calculating a mutual force of a motor in which a coil and a magnet or one of these members are arranged so as to be relatively movable to utilize a mutual force. By only once finding the magnetic flux density distribution by the coil or magnet constituting the member on one side, the mutual force and other necessary values in any state and condition of the coil by the coreless or slotless structure constituting the member on the other side, A method for calculating a mutual force of a motor, wherein the mutual force is obtained by utilizing a property of mutual inductance and a law of conservation of energy.