JP3595784B2 - Ground coil for magnetic levitation railway - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a ground coil used for at least levitation of a magnetic levitation railway.
[0002]
Problems to be solved by the prior art and the invention
In a magnetic levitation railway, ground coils for levitation, guidance, and propulsion of a vehicle are continuously installed in a guideway. The ground coils have a length corresponding to the pole pitch of the superconducting magnets of the vehicle (longitudinal distance between centers of adjacent superconducting coils in the same superconducting magnet) and are continuously installed at an equal pitch. For example, in the case of the Yamanashi experimental line, ground coils for levitation and guidance are arranged at an equal pitch of 45 cm.
[0003]
The superconducting magnet on the vehicle is vibrated at a specific frequency corresponding to the vehicle speed, and depending on the resonance frequency of the superconducting magnet, the heat load increases and the amount of liquid helium vaporized increases. In order to prevent such inconvenience, for example, it is conceivable to set the resonance frequency higher than the frequency generated at the normal operation speed of the magnetic levitation railway. However, in order to realize this, it is necessary to make the superconducting magnet strong by weight. Further, it is necessary to increase the capacity of the refrigerator for reliquefying the vaporized helium, which leads to an increase in weight and power consumption. Therefore, in reality, it is very difficult to set the resonance frequency of all of the plurality of vibration modes of the superconducting magnet to be excited to be higher than the frequency generated at the normal operation speed of the magnetic levitation railway.
[0004]
Therefore, while assuming that the resonance frequency exists within the normal operating speed range of the maglev railway, it is also possible to avoid running the maglev railway at a constant speed at such a resonance frequency. Conceivable. In other words, the superconducting magnet is designed so that a resonance frequency exists when the magnetic levitation railway travels at a predetermined speed αkm / h, which is generally considered to be less likely to travel at a constant speed.
[0005]
However, the resonance frequency of the superconducting magnet is not always constant due to manufacturing variations, and it is necessary to consider the respective resonance frequencies of a plurality of superconducting magnets in one knit. Therefore, it is necessary to restrict traveling in a speed range having a certain width. Furthermore, even if α km / h, which is considered to be less likely to travel at a constant speed, is assumed, this is only an assumption, and depending on various circumstances, there is a situation where the vehicle must travel at a constant speed at such a speed. Conceivable.
[0006]
Therefore, an object of the present invention is to provide a ground coil that can prevent a situation in which the resonance frequency coincides with the resonance frequency as much as possible, even on the premise that the resonance frequency exists within the normal operation speed range of the maglev railway.
[0007]
Means for Solving the Problems and Effects of the Invention
In order to achieve the above object, the ground coil of the maglev railway according to claim 1 is installed continuously in the guideway of the maglev railway along the traveling direction of the vehicle. They are mounted at equal pitch. According to the present invention, the superconducting magnet mounted on the vehicle is excited at a specific resonance frequency because the ground coils for levitating are arranged at an equal pitch. By mounting in this manner, the peak of the resonance frequency can be reduced. As a result, even if it is assumed that the resonance frequency exists within the normal operation speed range of the magnetic levitation railway, a situation in which the resonance frequency matches the resonance frequency is less likely to occur than in the related art. Therefore, the heat load is smaller than in the prior art, and the amount of liquid helium vaporized can be suppressed. This means that the capacity of the refrigerator for reliquefying the vaporized helium can be made relatively small. In addition, since the resonance frequency itself is allowed to exist in the frequency range that occurs at the normal operating speed of the maglev railway, the weight and power consumption of the superconducting magnet are reduced by placing it firmly on the superconducting magnet. There is no inconvenience such as an increase.
[0008]
By the way, since it is important to arrange the ground coils so that the mounting pitches thereof are unequal, the ground coils themselves may be formed in a size corresponding to the unequal pitch, for example (claim 2). They may be formed in the same size (claim 3). Even if the superconducting magnets are formed at the same size, if the mounting pitch itself is not uniform, the degree of vibration of the superconducting magnet at a specific resonance frequency can be reduced as compared with the conventional configuration.
[0009]
In terms of suppressing the peak of the calorific value of the superconducting magnet, all of these are more advantageous than the conventional configuration. However, when the ground coil is formed in a size corresponding to the unequal pitch as in claim 2, However, it is more advantageous in terms of levitation force than forming them in the same size as in claim 3. In other words, when the same size is used as in the third aspect, a gap is opened between the coils, so that a floating force cannot be obtained in this portion. This is because, if the ground coil is formed in a size, the levitation force can be easily obtained continuously.
[0010]
When the mounting pitch is unequal, it may be configured randomly as described in claim 4, or may be configured to be repeated in a fixed order as described in claim 5. For example, even when two types of pitches are used, they may be arranged alternately or randomly.
[0011]
Regarding the superiority and the inferiority of the two, it is rather desirable to arrange them randomly from the following viewpoints. For example, assuming that two types of pitches of A and B are used, if they are arranged alternately, excitation frequencies for the superconducting magnets include those due to A and B and those due to A + B. Therefore, even when coils of two types of pitches are arranged, there is an optimal solution that minimizes the influence of A, B, or a combination thereof (A + B, A + A + B, A + B + B, etc.). In addition, the response magnification of these A, B, or a combination thereof to the excitation frequency is qualitatively smaller when compared to A alone or B alone. Therefore, from such a viewpoint, it is not always optimal to arrange them alternately.
[0012]
Taking into account the degree of influence due to the combination of the unequal pitches, as described in claim 6, when the unequal pitches are n (n ≧ 2), the addition to the superconducting magnet mounted on the vehicle is considered. The oscillating frequency is determined to be an unequal pitch in which the influence of each of n types of pitches and the combination of two or more n types of pitches out of n types is relatively small. " It is also considered effective to adopt
[0013]
The ground coil to which the present invention is applied is only required to exhibit at least a levitation function of a vehicle, and can be applied to a levitation coil, a levitation / guide coil, a levitation / propulsion coil, a levitation / guide / propulsion coil, and the like.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments to which the present invention is applied will be described with reference to the drawings. It is needless to say that the embodiments of the present invention are not limited to the following examples, and can take various forms as long as they belong to the technical scope of the present invention.
[0015]
FIG. 1 is a sectional view showing a guideway 13 and a superconducting linear vehicle (hereinafter, simply referred to as a vehicle) 10 of a superconducting maglev railway, and FIG. It is explanatory drawing which shows an outline.
The levitation and guide coils 1 and 1 'are coils that can realize the levitation and guidance functions with one coil, and are continuously arranged on the side wall of the guideway 13 having a substantially U-shaped cross section in the vehicle traveling direction. . Here, those arranged on one side wall are numbered 1 and those arranged on the other side wall are numbered 1 '. It should be noted that there is a feature in what intervals are arranged when the objects are continuously arranged along the vehicle traveling direction. This point will be described later, and the basic configuration will be described first.
[0016]
On both sides of the vehicle 10, superconducting magnets 20, 20 'are vertically mounted so as to face the levitation and guide coils 1, 1', respectively. The superconducting magnet 20 faces the levitation / guide coil 1, and the superconducting magnet 20 'faces the levitation / guide coil 1'. In the following description, as for configurations that are present on both the left and right sides in the traveling direction of the vehicle, by adding 'to one number while using the same number, it is determined that they are on the same side depending on the presence or absence of'. It will be shown. The vehicle body of the vehicle 10 has a passenger compartment, a door for getting on and off (not shown), and the like, like the vehicle body of a conventional railway vehicle that travels on iron wheels and rails. Since the vehicle 10 is required to be thoroughly reduced in weight and increased in strength due to the unique traveling condition of ultra-high speed levitation traveling, an aluminum alloy is used as a body material of the vehicle body, and its structure is also It has a semi-monocoque structure similar to an aircraft. In addition, the surface of the vehicle body is generally smooth to minimize air resistance during traveling.
[0017]
The vehicle body is mounted on a trolley, and the trolley is provided with superconducting magnets 20, 20 'and tires 12. The vehicle 10 is propelled by the propulsion generated by the magnetic interaction between the superconducting magnets 20, 20 'and the propulsion coil (not shown). The superconducting magnets 20 and 20 'are configured such that a plurality of superconducting coils are installed adjacent to each other in the longitudinal direction of the vehicle. Each superconducting coil is housed in a stainless steel inner tank container (not shown) together with liquid helium. This superconducting coil is formed by winding a superconducting wire such as a niobium-titanium alloy several thousand times, and generates a magnetic field by flowing an electric current. Then, it is stored together with liquid helium in a stainless steel inner tank container (not shown). The superconducting magnets 20 and 20 'are also provided with an in-vehicle refrigerator (not shown) having liquid helium for cooling the superconducting coil to maintain the superconducting state. The polarities of a plurality of adjacent superconducting coils constituting the superconducting magnets 20 and 20 ′ are arranged such that adjacent poles have different polarities (that is, N poles and S poles are alternately arranged). The distance between the centers of the adjacent superconducting coils is called "pole pitch".
[0018]
On the other hand, as shown in FIG. 2, the floating / guide coils 1 and 1 'comprise a closed circuit in which the upper coils 2 and 2' and the lower coils 3 and 3 'are null-flux connected. Specifically, the upper coil 2 of the levitating / guide coil on one side wall and the upper coil 2 'of the levitating / guide coil 1' facing the opposite side (on the opposite side wall) are connected via null flux cables 4,5. Null flux connection as shown in FIG. When the vehicle 10 is seated on the ground via the tires 12, the vertical center of the superconducting magnets 20, 20 ′ on the vehicle 10 side and the vertical center of the levitation / guide coils 1, 1 ′ are on the same horizontal line. Is set as in
[0019]
Although not shown, a propulsion coil is disposed between the side wall of the guideway 13 and the floating / guide coils 1 and 1 '. Specifically, the propulsion coil is composed of two layers of front and back. Therefore, after the propulsion coil of two layers of front and back is attached to the side wall of the guideway 13, the levitating / guide coils 1, 1 'are attached to the surface thereof. The ground coil has a total of three layers. The propulsion coils are continuously arranged along the traveling direction of the vehicle, and power for generating a magnetic field from each propulsion coil is supplied from a power conversion substation (not shown). More specifically, in the present embodiment, a three-phase alternating current (a U-phase current, a V-phase current, and a W-phase current) having a frequency corresponding to the vehicle speed to be driven flows through each propulsion coil. Then, since the magnetic fields generated from the respective propulsion coils overlap, as a result, a magnetic field in which the N pole and the S pole alternately and continuously change is generated from the propulsion coil.
[0020]
With such a basic configuration, the following levitation force, guidance force, and propulsion force are obtained.
{Circle around (1)} When the levitation vehicle 10 is traveling at low speed via the tires 12, the positional relationship between the superconducting magnets 20, 20 'and the levitation / guide coils 1, 1' is set as described above. Further, since the upper and lower coils 2, 2 ', 3, 3' are null-flux-connected, the flux linkage of the levitation / guide coils 1, 1 'is 0, the current is 0, and the electromagnetic running resistance is 0. When the vehicle 10 levitates (with the tires 12 retracted), the vertical center of the superconducting magnets 20 and 20 'shifts below the vertical center of the levitating / guide coils 1 and 1', and the upper coil 2 A difference occurs in the magnetic flux linking between the 2 'and lower coils 3, 3', and a current as shown in Fig. 3 is induced in the upper and lower coils 2, 2 ', 3, 3', and the superconductivity is generated by repulsion and attraction. A levitation force is generated to return the magnets 20, 20 'upward, and the magnet 20 and 20' is stabilized at a position balanced with the weight of the vehicle. Also in this case, the upper and lower coils 2, 2 ', 3, 3' effectively generate a levitation force with a small current, so that the electromagnetic traveling resistance can be reduced.
[0021]
{Circle around (2)} When the guiding vehicle 10 is located at the center of the guideway 13, the levitating / guide coils 1, 1 ′ are arranged symmetrically with respect to the longitudinal center line of the guideway 13, and the upper coil 2 facing the guideway 13. , 2 ′ are null-flux connected via null flux cables 4, 5, so that the flux linkage of the levitation / guide coils 1, 1 ′ is 0, the current is 0, and the electromagnetic running resistance is 0. . When the vehicle 10 is displaced in the left-right direction during the levitation traveling, a difference occurs in the magnetic flux linking between the left and right upper coils 2 and 2 ′ and between the left and right lower coils 3 and 3 ′, and a current as shown in FIG. Is induced, thereby producing a guiding force for returning the superconducting magnets 20, 20 'to the center.
[0022]
(3) Power is supplied to the propulsion propulsion coil (in this embodiment, three-phase AC power) to generate a magnetic field, and each of the three propulsion coils adjacent to each other in the traveling direction of the vehicle corresponds to the vehicle speed to be driven. When three-phase alternating currents of a frequency (U-phase current, V-phase current, W-phase current) are respectively supplied, the magnetic fields generated from the respective propulsion coils overlap, and as a result, the N-pole and the S-pole alternately and continuously. Is generated. As a result, interaction (attractive force or repulsive force) occurs between each propulsion coil and the superconducting magnets 20 and 20 'on the vehicle 10 facing the vehicle 10, and the vehicle 10 is propelled. This utilizes the principle of propulsion by a linear synchronous motor.
[0023]
Next, how the levitation and guide coils 1 and 1 'are arranged along the traveling direction of the vehicle will be described with reference to FIG. In this embodiment, since the left and right levitation and guide coils 1 and 1 'are arranged symmetrically, one levitation and guide coil 1 will be described.
[0024]
Conventionally, the floating / guide coils 1 having the same shape are continuously arranged at the same pitch. In the present embodiment, however, the pitches are made to be unequal. Here, the pitch refers to the distance between the centers of the adjacent floating / guide coils 1. In the case of non-uniform pitch, theoretically, it is considered that resonance does not occur if the distance between all the floating and guiding coils 1 is completely random and non-uniform. However, as a practical matter, it is difficult to make them completely random, so that unequal pitches are formed by combining a plurality of types of pitches. Three specific examples in that case will be described.
[0025]
In the example shown in FIG. 5A, five types of levitation / guide coils 1 having five different widths are arranged in a predetermined order within a fixed span S, and five levitation / guide coils 1 arranged in that order are provided. Are repeatedly arranged. That is, when the levitation / guide coils 1 having five different widths are represented as A, B, C, D, E, and F, respectively, A → B → C → D → E → F → A → B → C → D → E → F →...
[0026]
In the example shown in FIG. 5B, the levitation / guide coils 1 having five different widths are used as in the case of FIG. 5A, but they are randomly arranged. That is, the floating / guide coils 1 having the same shape do not repeatedly appear in the same order.
[0027]
In the example shown in FIG. 5C, the floating / guide coils 1 having the same shape are used. However, by making the spacing between the adjacent floating / guide coils 1 different, an uneven pitch is formed as a result. are doing.
Here, the range that can be adopted as the unequal pitch will be described. Basically, the upper limit is half the pole pitch. The pole pitch is the longitudinal distance between the centers of adjacent superconducting magnets in the same superconducting magnet 20, 20 '(that is, the length of one set of N poles and S poles). If the upper limit is exceeded, the N and S poles simultaneously enter the same levitation and guide coils 1 and 1 ', and current does not flow well in the levitation and guide coils 1 and 1'. As a result, the levitation force is reduced. This is because it does not occur. As the lower limit value, a physically configurable size can be adopted.
[0028]
The following effects can be obtained by making the pitch unequal. That is, the reason that the superconducting magnets 20 and 20 ′ mounted on the vehicle 10 are vibrated at the specific resonance frequency is that the ground coils for floating are arranged at an equal pitch. Are arranged at unequal pitches, so that the peak of the resonance frequency can be reduced. As a result, even when the resonance frequency exists within the traveling speed range that the vehicle 10 can take, a situation that matches the resonance frequency is less likely to occur than in the related art. Therefore, the heat load is reduced as compared with the conventional case, and the amount of liquid helium vaporized can be suppressed, and the capacity of the refrigerator can be relatively reduced.
[0029]
5 (a) and 5 (b) show the levitation / guide coils 1 and 1 'formed in a size corresponding to the unequal pitch, whereas in the case of FIG. However, the flying and guiding coils 1 and 1 'themselves have the same size. 5A and 5B are more advantageous than the conventional configuration in terms of suppressing the peak of the heat generation amount of the superconducting magnets 20 and 20 ′. ) Is more advantageous. That is, in the case of FIG. 5 (c), no levitation force is obtained in the gap between the levitation / guide coils 1 and 1 ', whereas in the case of FIGS. This is because a floating force can be obtained.
[0030]
5A and 5B are compared. 5A and 5B assume five types of pitches, but first consider two types of pitches. For example, assuming that two types of pitches of A and B are used, if they are arranged alternately, excitation frequencies for the superconducting magnets include those due to A and B and those due to A + B. Therefore, even when coils of two kinds of pitches are arranged, there is an optimal solution that minimizes the influence of A, B, or a combination thereof (A + B, A + A + B, A + B + B, etc.). In addition, the response magnification of these A, B, or a combination thereof with respect to the excitation frequency is qualitatively smaller than that of A alone or B alone.
[0031]
Therefore, from such a viewpoint, it is not always optimal to arrange them alternately, and it can be said that the random arrangement increases the possibility of reducing the peak of the resonance frequency. Further, as described above, it is also effective to set in consideration of the degree of influence due to the combination of unequal pitches. In the case of FIG. 5B, there are five types of pitches, but all or a combination of them may be considered.
[0032]
On the other hand, when the coils are arranged in a predetermined order within the fixed span S as shown in FIG. 5A, a set of five levitation and guide coils 1 arranged in that order is created in advance, and Need only be arranged on the guideway 13 in order. Therefore, this method is also effective in terms of work efficiency.
[0033]
In FIGS. 5A and 5B, for example, it is assumed that there are five types of different pitches. For example, when three types are used, the upper limit is half of the pole pitch and the lower limit is determined by the hardware configuration as described above. It is conceivable to adopt a pitch of 3. Of course, other combinations may be used. When two types are used, for example, it is conceivable to adopt a half (further) pitch of ピ ッ チ and a pitch of ３ of the pole pitch.
[0034]
[Others]
(1) In the above embodiment, the levitation and guide coils 1 and 1 'have been described as examples. However, it is sufficient that at least the levitation function of the vehicle 10 can be exhibited. A coil that exhibits only the levitation function, a coil that exhibits the levitation and guidance function, The present invention can be applied to a coil exhibiting a levitation / propulsion function, or a coil exhibiting all functions of levitation / guide / propulsion with one coil. In particular, when the present invention is applied to a coil that performs all of the functions of levitation, guidance, and propulsion with one coil, it is necessary to secure the propulsion function. And two thirds of the pitch are also effective.
[0035]
(2) In the above embodiment, an example was described in which the upper coils 2, 2 'and the lower coils 3, 3' constituting one levitation and guide coil 1, 1 'have the same shape and the same dimensions. However, these can be realized even if they are not the same shape and the same size.
[0036]
(3) In the above embodiment, the coil having the levitation function is installed on the side wall of the guideway. However, this can be realized by installing the coil on the traveling road surface (U-shaped bottom surface).
(4) Although the guideway 13 has a U-shaped cross section in the above embodiment, various shapes such as an inverted T-shape, a box-shaped cross section, and a plate can be used. Is not limited to this.
[Brief description of the drawings]
FIG. 1 is a sectional view showing a guideway and a superconducting linear vehicle of a superconducting magnetic levitation railway according to an embodiment.
FIG. 2 is an explanatory diagram showing an outline of arrangement and wiring of a levitation / guide coil.
FIG. 3 is a circuit diagram illustrating a flow of a current for levitation flowing through a levitation / guide coil.
FIG. 4 is a circuit diagram showing a flow of a current for guiding a levitation / guide coil.
FIG. 5 is an explanatory diagram of an arrangement of a levitation / guide coil along a vehicle traveling direction.
[Explanation of symbols]
1, 1 ': floating / guide coil, 2, 2': upper coil, 3, 3 ': lower coil, 4, 5: null flux cable, 10: vehicle, 12: tire, 13: guide way, 20, 20 '… Superconducting magnet

Claims (6)

A ground coil that is continuously installed in a guideway of a magnetic levitation railway along a traveling direction of a vehicle and exerts at least a levitation function of the vehicle,
A ground coil for a magnetic levitation railway, wherein the ground coils are mounted at irregular pitches. The ground coil of a magnetic levitation railway according to claim 1,
The ground coil according to claim 1, wherein the ground coil is formed in a size corresponding to the unequal pitch. The ground coil of a magnetic levitation railway according to claim 1,
A ground coil for a magnetic levitation railway, wherein the ground coils are formed in the same size. The ground coil of the magnetic levitation railway according to any one of claims 1 to 3,
The unequal pitch is random, and a ground coil of a magnetic levitation railway. The ground coil of the magnetic levitation railway according to any one of claims 1 to 3,
A ground coil for a magnetic levitation railway, wherein when the unequal pitches are n (n ≧ 2) types, the n types of unequal pitches are repeated in a certain order. The ground coil of the magnetic levitation railway according to any one of claims 1 to 3,
When the unequal pitch is n (n ≧ 2), the excitation frequency for the superconducting magnet mounted on the vehicle is caused by each of the n types of pitches, and two or more of the n types and n or less A ground coil for a magnetically levitated railway, characterized by an unequal pitch in which the influence of each combination of pitches is relatively small.

Images