DE2315060C3 - Unear synchronous motor for an electromagnetically guided levitation vehicle - Google Patents

Description

The support coils 18/4 and 185 each opposite the field coils 16Λ and 16A. There is also a lead coil

19 vertically in the ground so that it is provided between the field coils 17Λ and 175 . The support coils 18Λ and 185 and a lead coil 1? Are short-circuited coils. They can also consist of conductive layers. A drive coil 20 of the linear synchronous motor lies between the support coils 18Λ and 185. The width L or the lateral dimension of the drive coil 20 corresponds to the distance between the field coils 17A and '75. The Triebspuie 20 is rectangular. It is excited by an alternating current source in order to generate a traveling wave of a magnetic flux depending on the speed of the moving vehicle. The vehicle 15 is moved by the driving force based on the interaction between the magnetic. Traveling wave and the magnetic field of the coils 17/4 and 175 is based. Furthermore, the travel of the vehicle 15 generates a magnetic repulsion between the field coils 16/4, 16Ö and the support coils 18Λ 185 and between the field coils 17/4, 17S and the lead coil 19, thereby lifting the vehicle above the ground and steadily on the track keep.

In Fig. 9 also shows the distribution of the horizontal component Bx and the vertical component ßyder the density of the magnetic flux which is generated by the field coils 17Λ and 17ß in the plane of the drive coil 20. In Fig. 9, the shape and position of the field coils 17/4 and 17ß do not correspond to the shape and position of the drive coil 20. It should now be pointed out that there is an apparent or virtual coil 17, as indicated by dashed lines in FIG the drive coil 20 corresponds. As can be seen from FIG. 9, the horizontal flux density Bx is highest on the opposite sides 20a of the drive coil 20. This large magnetic flux acts on the current flowing through the sides 20a of the drive coil and creates attraction and repulsion in the linear motor, thereby causing vertical oscillation which adversely affects the levitation or lifting of the magnetic system. Furthermore, in the plane of the drive coil 20 at the sides 20a, the vertical flux density By has a slight increase in relation to the lateral displacement. Therefore, a horizontal "spring constant" or spring force, which is proportional to the product of the current flowing through the coil sections 20a and the gradient of the flux density By , has a large but unstable value in the position of the sides 20a shown, which increases the lateral stability of the vehicle is deteriorated.

The designation "Federkonstarf;" means a magnetic force necessary for the lateral displacement of the vehicle 15 from its central position or for a return of the vehicle to the central position is required, while a force that the vehicle in forcing a shift is called "unstable spring constant". A force that the central position is called a "stable spring rate".

In FIG. 10, the positional relationship is now Driving coils and the field coils for the in the F i g. 8 and 9 shown arrangements. The drive coils

20 are spaced at regular intervals that have an electrical angle of 120 ° with respect to the longitudinal magnetic field corresponding to the Field coils 17 is generated. The drive coils 20 are each via switching devices, such as 1 hyrist-oren, not shown, with an alternating current source connected. The switching devices distribute the current to the respective drive coils in precise sequence and exact switching intervals, depending on the speed of the vehicle.

11 and 12 also show changes in the drive force F, the force Γ acting in the vertical direction and the lateral spring constant K that act on the vehicle when the

ίο Vehicle moves along the track. F i g applies here. 11 for a case in which a lead angle γ for controlling the thyristors to the induced voltage is zero. The F i g. 12 applies to a lead angle of 20 °. 11 and 12, the respective maximum values of the vertical force and the lateral spring constant, which are disadvantageous for stable running of the vehicle, are considerably large compared to the driving force. In addition, the changes in the former are large Periodic or oscillatory forces. Therefore, with the coil arrangement already known, it is difficult to achieve stable travel of the vehicle. In this context, it can be seen from the figures that operation with an advance angle of 20 ³ results in less drive force with a more unstable spring constant compared to operation with an advance angle of "zero". Regarding the problem of magnetic lift-off, it should be pointed out that the first-mentioned operation with a control advance of 20 ° is more advantageous, since in this operation the force acting in the vertical direction is repulsive. It is possible that even the magnetic field applied to the drive coil may be of some use in raising the vehicle by properly selecting the advance angle. The in the F i g. However, the coil arrangement shown in FIG. 8 is in no way suitable for practical use unless some measures are taken to reduce the large vibration components of the force acting in the vertical direction and the lateral spring constant.

It is therefore an object of the present invention to provide a linear synchronous motor for an electromagnetic to indicate the guided suspension vehicle in which the vibration components are in the vertical direction acting force and the lateral spring constant are largely eliminated.

This object is achieved according to the invention in that the ratio of the width of the drive coils to the width of the field coils or to the distance between the sides of the field coils assigned to the drive coils is selected to be greater than 1 such that it falls within the range expressed by the following inequality: in Fig. 2a the width of the field coils, 2b the width of the drive coils and g the mean distance between the path of the field coils and the drive coils during normal operation of the vehicle:

I +

/) α

In another embodiment, it is possible that the ratio of the width of the field coils to the width of the 6s drive coils is selected to be greater than 1 such that it falls within the range expressed by the following inequality, in which 2; i is the width of the! "eidspulen, 2b the width of the drive coils and g the mean distance

between the path of the field coil and the drive coil mean during normal operation of the vehicle:

1 +

G '2 h "

g I +

77

In both embodiments, the vibration components are those acting in the vertical direction Force and the lateral spring constant are significantly reduced, so that a stable operation of the Vehicle is possible. The second embodiment is particularly advantageous when the dimensions of the Drive coil are restricted for some reason.

In the following, embodiments of the invention and their theoretical principles are based on the Figures explained in more detail. It shows

Fig. 1 is a perspective view of a magnetic Suspended vehicle, which is driven by the linear synchronous motor according to the invention, with the Arrangement of the coils on the vehicle and on the track,

F i g. 2 is a front view of the vehicle and the track;

F i g. 3 is a schematic diagram corresponding to the lower Part corresponds to the arrangement shown in FIG. 2,

4 shows the distribution of the magnetic flux at the in the F i g. 3 coils provided,

F i g. 5 curves showing the driving force, the force acting in the vertical direction and the lateral spring force in each case as a function of the ratio of the widths of the FIG. 3 illustrated drive and field coils indicate.

F i g. 6 and 7 each the essential part of other linear synchronous motors according to the invention,

F i g. 8 shows the arrangement of the coils in the already known levitation and drive system with a Linear synchronous motor,

F i g. 9 shows the distribution of the magnetic flux in the case of the FIG. 8 shown known coil arrangement,

F i g. 10 the positional relationship of the drive and field coils in the already known linear synchronous motor (Fig. 8) and

Figures 11 and 12 are graphs showing the changes in Driving force, the force acting in the vertical direction and the lateral spring force, which is already used in the known system (Fig.8 to 10) along the track act on the vehicle.

In the F i g. 1 to 3, a magnetic levitation vehicle 1 is shown, which is driven by the linear synchronous motor according to the invention. The vehicle 1 comprises a passenger compartment 2 and an underframe 3 which is attached to the underside of the passenger compartment 2. The underframe is provided with a longitudinal groove 3G along its center line and with pairs of field coils 4A 45 and 5 A 55. These field coils consist of superconductors and generate a constant magnetic field. The coils 4A and 45 are provided in a horizontal position on the lower part of the underframe 3 symmetrically to the center line of the groove 3G or of the vehicle 1. It goes without saying that several such field coil pairs are arranged at equal intervals along the length of the vehicle 1. On the other hand, the field coils 5A SB are provided in vertical days symmetrically to the center line and adjacent to the soap walls of the groove 3G. The coils 5.4 and SB, the number of which correspond to the coils 4/4 and 4ß, are provided at equal intervals along the length of the vehicle.

Opposite the vehicle thus constructed, a track EP with a protrusion or wall EC is provided along the center line on the floor to guide the moving vehicle. The profile of the track corresponds to the undercarriage of the vehicle, but with a sufficient distance between them

The track EP is also provided with support spools 8/4 and 85. A number of the pairs formed from these coils are provided in the horizontal direction at equal intervals below and along the row of the field coils 4A and 45. Each support coil consists of a wound and short-circuited conductor or a conductor layer. In the central wall fTC and at the same distance from the field coils SA and SB there are guide coils 6 which serve to maintain the lateral stability of the vehicle. Each lead coil also consists of a closed winding or a conductive layer. A number of such coils are provided along the track. A number of rectangular drive coils 7 are embedded in a horizontal position along the center line of the track.

In the coil arrangement described above, the magnetic fields generated by the field coils AA, 45 and SA, SB mounted on the vehicle and moved with the vehicle act on the support coils 8A 85 and the lead coils 6 on the bottom side to generate a carrying force and a carrying force, respectively . Furthermore, the drive coils 7 are excited with a three-phase alternating current, which is fed in from an external power source in order to generate a traveling wave of a magnetic flux that acts on the magnetic field of the field coils 5A SB to keep the field coils and thus the vehicle synchronized with the movement of the magnetic wave to move through the drive coils. Therefore, by controlling the frequency of the three-phase alternating current energizing the drive coils, the traveling speed of the vehicle can be controlled.

The width 26 of the drive coil 7 is greater than the distance between opposing field coils

45. SA and 55. From FIG. 4, which shows the horizontal and vertical components of the distribution of the magnetic flux generated in the vicinity of the drive coil by an imaginary horizontal coil 5 formed by the lower sides of the two field coils SA and SB , it can be seen that the horizontal Flux density Bx on the sides 7 a of the drive coil 7 is smaller than in the corresponding positions of the in FIG. 9 illustrated drive coil 7. It should also be pointed out that the lateral gradient of the vertical flux density By in the same positions in the arrangement of FIG. 4 is smaller and opposite to the corresponding gradient in the arrangement of FIG 3 and 4 the vertical attraction and repulsion, which is determined by the product of the current flowing through the drive coil 7 and the magnetic flux density Bx in part Ta of the drive coil 7, compared to the corresponding forces in the coil arrangement already discussed ( Fig. 8 and 9)

Furthermore, the lateral spring constant, which is the product of the current flowing through the drive coil 7 and the magnetic flux density By in the part 7a, becomes a very small unstable one

Constants or even made into a stable spring constant.

The interactions between the coils recorded above are subsequently illustrated with the aid of a mathematical approximation calculation investigated. the

ß.Y =

horizontal and vertical components ßA and 5j the magnetic flux density caused by the imaginary field coil 5 in the drive coil can be expressed by the following equations:

(X- α) ² H- g (x + ei) ²

fli =

Λ "~ Cl

-V - il

/ I ₀ = magnetic permeability of air.

a = half the width of the imaginary field coil 5,

g = mean distance between the drive coil 7 and the imaginary field coil 5 during normal travel of the vehicle.

.v = lateral departure from the center line of the imaginary field coil 5 and

/ _; = magnetomotive force of the imaginary field coil.

The length of the field coils 5A5ß or the imaginary Field coil 5 can be assumed to be infinite or significantly greater than the width 2a of the imaginary coil 5 will.

Furthermore, the width of the drive coil 7 should be designated by 26. The length of the same coil along the length of the path is intended to be designated by c. The magnetomotive force through the drive coil 7 is intended to be designated by _{/ a.} The maximum values of the driving force and the force acting in the vertical direction (in each case F ₁ T), which act between the drive coils and the field coils, and the maximum value of the lateral spring constant (K) can then each be expressed by the following equations:

= 2 j By

-H

I ₁₁ -Ux = ^ - L

ei) ² + g ²

(b-tf

T = 2 Bx ■ L ₁ ■ Az =

(b - af + g ² (Y + a) ²

dx

² - (/) + a) ² + a) ² "+ g ² f

In the following, the terms "vertical force" and "lateral spring constant" are intended as a reference to be understood on the respective maximum values of these forces, if not expressly something other is emphasized.

The relationships of the ratio of the width of the drive coil 7 to the field coil 5 with respect to the driving force F, the vertical force 7 "and the lateral spring constant K, which are determined by the equations (3) to (5), are shown in FIG . 5, from which three important properties can be taken:

(1) The driving force F decreases approximately in proportion to the ratio b / a in the range where this ratio is smaller than one. It only decreases slightly in the area in which the ratio b / a is greater than one.

(2) The perpendicular force Γ decreases steeply when the ratio b / a deviates from one

(3) The lateral spring constant K takes a maximum unstable value (magnetic repulsion) in the range where the ratio b / a is close to one. However, the constant K decreases steeply when the ratio deviates from one, eventually becoming a stable spring constant (magnetic attraction).

From the above description, although the ratio b / a should preferably be one from the point of view of the driving force F , this ratio one also has a peak value of the perpendicular force more than twice as large as the driving force with a maximum value of unstable lateral spring constant K is assigned which hinders any stable drive of the vehicle. In particular, a compromise between the driving force on the one hand and the vertical force and the lateral spring constant is necessary for practical operation of the vehicle. When designing the system, the driving force is reduced somewhat in order to keep the vertical force and the lateral spring constant below reasonable levels. It goes without saying that the reduction in driving force can be made less difficult by the

609 653/267

Ratio b / u is selected in a range greater than one, as when a ratio smaller than one is selected, since in the first range of the ratio the gradient of the decrease is smaller.

With regard to the lateral spring rate: i note that a stable spring rate can be obtained by choosing the variables in equation (1) to make the constant K a negative value. Since the average .Spulenabstand tr, a fraction of the width a of the field coil ic is 5, a value g can be ² to a value of / ² are neglected, that is, a ^2> g. ² Therefore, the condition that the lateral spring constant is a stable constant can be obtained from the equation (5) and expressed as follows:

From equation (9) it then follows:

0.2 /,

0.4 = 0.4 =

0.2 0.4

I 2-0.2

1.5 <

+ g

16)

However, as mentioned above, the driving force / - "decreases as the width of the drive coil 7 increases with respect to the width of the field coil 5. Therefore, an unlimited increase in the width of the drive coil 7 is not suitable for practical use because it requires an extraordinary increase in the magnetomotive force of the drive coil. From the practical point of view, the allowable decrease in the drive force can be set to be half the peak value corresponding to the ratio b / a- \ . This condition is determined by the following equations ; In particular, equation (3) results in:

In particular, it is thus determined that the width 2t of the I nebspule should be in the range from 1.2 to 2 m.

In the following, a further approximation is carried out to limit the width of the drive coils by paying particular attention to the unstable lateral spring constant. It is believed that, from the practical point of view, the unstable lateral spring constant K must be reduced by half from its peak value. From equation (5), in which a ² > g2 , we get:

h ^ α

(10)

By inserting the left hand side of equation (9) into the Equation (10) is used, we get:

1 +

/ 2g

• (II)

α + g - j lay : S h 5Ξ a + g + \ 2ag. (7) Furthermore, equations (6) and (7) result in:

This results in:

1 -t-

H a

S I +

+ l'2flg. (8th)

19)

40

45

In the range (Fig. 5) specified by the above condition, the decrease in the perpendicular force T is greater than the decrease in the driving force F. In addition, the lateral spring constant takes a negative value, which means a stable spring constant. This effectively suppresses the reciprocating vertical force that prevents the vehicle from hovering in a stable manner. Accordingly, the vibration of the vehicle decreases. Furthermore, the stable spring constant causes the vehicle to return to the normal central position when it moves away from the normal position is driven.

In tests, the above condition is numerically estgelegt It was assumed that the width 2a of the 65 ^r eldspule 0.8 m and the average distance g between ler field coil and the drive coil during the 'iormalbetriebs of the vehicle be 0.2 m.

60

dpi Prf a ' ^{S 7 Smd Further} examples

^{the line} ^ motors, λ _c ^ngS p! with fZ -ti J '% ^P , " ^{len arrangements} deviate from the ^{coil arrangements explained} on the basis of the in'η _{bls c} ^5. ei'", ^h '^g; ^{6 lst a Paa} r of field coils 9Λ 9B from edges ^Pra H f ^iter '^"senkre daughters direction in both E η Il f ^{sub eslells} S of the vehicle 1 is provided. A complementary pair of guide and bearing coils

BotlJnT If ^{"in senkrec} hter direction on the iedorh ^{Unge! Ahr} ^ genüber to the field coils, heel ,,, * ^{b ln, eZUg on the} field coils down FeWsSp i1 ^8e0Pdnet · ^Weiterhi" is another K, T ^{S r a Su} P aleiter in a horizontal position

Hearkened ^g "" ^ ^Untersei th and in the center of Bod ^ n Τ "seen · ^{erg? Telis before,} and over the dartf out ⁶ '' ⁶ × ^{12 bSPUle} is ^to g ^eor dnet. It should be imatin ^ge c ^W 'T ⁿ · ^{that the} field coil 11 is no XXh k ^{P e} · ^{As the coil 5 in the} first SSÄ ^eiS . ^PI - ^eI · ^{SOndern Rather a real} «which can be the 5 ^{P e 1St} · ^{Even with this} coil arrangement, de reduction of the undesired vertical

rder H Τ ',' ^unstable "lateral spring constants m eme '" ,, hT ^a i ^{extension of unstable} spring constants BreTte? H c ^ ^{OnStante can be achieved} by the 12 and, ff ^{dSpUie λ} · ' ^{the width 2b of the} drive coil 12 and the mutere distance g between the coils 11

fillfelT. ^{TALK nndder by the} equations <9) or

ih ^S ^ ^s ™ s ^BSDL sen be adjusted *. are HpS ¹ "ρ μ ^61" V ^g · ⁶ g ^{represents estel} 'th coil arrangement darteste Mt? ^{P. Ulen 9} ^ ' ^{9B and} "^ vehicle in the section shown and three further coils, nällich

au Vl l ^T f ^s P ^{ulm 10} A 105 and a drive coil 12, Z ^Bod ^ " ^side provided, so that in the

"^ ¹¹¹ "" ^the total number of coils six ^first embodiment of Fig. 3 ^rae ^ pulen and ^ er base 4n

! ei η ^ aT ^ ^{er Fahrae} ^ pulen and ^ er Bod «4n · len. so that the total number is eight. Therefore, VeJi ^ ^ ' ^g · ^{6 dar} £ ^est duck coil arrangement in the arrangement shown in a ^ " ^def Fj & ³ shown a more economic linear synchronous motor.

Ib UöU

In the case of the FIG. 7, a pair of drive coils 14A 14ß are arranged in the vertical direction on the bottom side E opposite the respective flanks of the underframe of the vehicle I and a complementary pair of field coils 13.4, 13S in the vehicle underframe opposite the respective drive coils. Furthermore, a ground-fixed lead coil 6 and support coils SA, 8ß are provided opposite additional vehicle-side pairs of field coils 5 / \, 5ß and 4A, 4ß. With this arrangement, the operating characteristics of the linear synchronous motor can be improved because the magnetic coupling between the vehicle coils and the ground coils can be designed individually for each coil group. In this connection it should be pointed out that in the case of the FIG. 3, the field coils 5A and 5ß are coupled to the lead coil 6 and the drive coil 7 shown in FIG.

It goes without saying that the electromagnetic relationship between the field coils 13A 135 and the Tricbspulcn 14Λ14ß in the general example shown in FIG. 6 corresponds to the exemplary embodiment shown. The conditions expressed by the equation (9) or (11) must also be observed in this case.

In the above embodiments, drive coils are used, the width of which is greater than that

ίο Width of the opposing field coils. However, it is also possible to choose the width of the drive coils so that it is smaller than the width of the opposite one Field coils. In this case, the condition for stable operation is achieved through similar processes and expressed by the following equation:

For this 5 sheets of drawings

Claims (3)

Patent claims: . 1.Linear synchronous motor for an electromagnetically guided levitation vehicle, which has field coils in the vehicle to generate a constant magnetic field, which in the route are both short-circuited support and guide coils for the magnetic levitation control and alternating current-fed drive coils to generate one that interacts with the field coils Traveling field are assigned, characterized in that the ratio of the width of the drive coils (7; 12; 14 A HB) to the width of the field coils (11; 13 A 13ß; or to the distance between the drive coils (7) assigned sides of the field coils (5A 5B) is chosen in such a way that it falls within the range expressed by the following inequality, in which 2a the width of the field coils, Ib the width of the drive coils and g the mean distance between the path of the field coils and the drive coils normal operation of the vehicle (1) mean: 2a ~ a ~ 2g 2. Linear synchronous motor for an electromagnetically guided levitation vehicle, which has field coils in the vehicle for generating a constant magnetic field, to which both short-circuited support and guide coils for the magnetic levitation control and AC-powered drive coils for generating a traveling field that interacts with the field coils are assigned in the route are, characterized in that the ratio of the width of the field coils or the spacing of the sides of the field coils assigned to the drive coils to the width of the drive coils is selected to be greater than 1 such that it falls within the range expressed by the following inequality in which 2a is the width of the field coils, 2b is the width of the drive coils and g is the mean distance between the path of the field coil and the drive coil during normal operation of the vehicle (1): 2Λ = h = ' 3. Linear synchronous motor according to claim 1, characterized in that the ratio of the Width of the drive coils is restricted to the width of the field coils in such a way that 55 60 The invention relates to a linear synchronous motor for an electromagnetically guided hover vehicle, which field coils in the vehicle to generate a constant magnetic field It shows, which in tier driving distance both short-circuited Carrying and conductor coils for magnetic suspension guidance as well as alternating sirom-fed Driving coils for generating a traveling field interacting with the field coils are assigned. In conventional vehicles, the wheels of which are driven by a motor, the locomotion of the vehicle caused by the frictional force between the wheels and the rails or the bed. However, the frictional force does not have its full effect on vehicles traveling at a speed of Drive 300 km / h or more. To solve this problem, various vehicle systems have been developed, where a vehicle is hovering or raised above the ground and without the help of the Frictional force between the wheels and the ground is driven. A linear motor is for such a thing Drive system suitable without frictional force. It is well known that a linear motor is an electric motor, which is arranged along a path, with either the armature or the field part of the motor floating Vehicle attached and the other parts are provided along the track, or vice versa. In order to lift the vehicle into the air, magnetic coils are attached to the vehicle in order to eivi to generate a magnetic field, and on the other hand an arrangement of short-circuited coils is provided in the ground. If with this arrangement the Vehicle over and along the on. Sp-jlen arranged on the ground moves, then the magnetic chain is linked Running field with the coils arranged in or on the floor, in order to generate an electric current in the induce the last-mentioned coils. The induced current creates another magnetic one Field that acts on the first magnetic field to create a repulsive force between the vehicle coils and manufacture the floor coils that raise the vehicle above the floor. However, merely raising the vehicle above the ground is not practical for operation sufficient. This is because certain guiding devices must be provided along the track to prevent the To keep the vehicle in its direction or on its course. With one already known for this purpose System ("Cryogenics and Industrial Gases", October 1969, pp. 19 to 24) are another series of Magnet coils on the vehicle and an arrangement of the short-circuited coils in or on the ground, in order to generate an electromagnetic force acting in the lateral direction, the moving Vehicle stops on course. The principle on which the operation of such a control device is based is essentially the same as the magnetic lift-off explained above. It is also no longer new (cf. literary position given above), the solenoids, the Either serve to manage the vehicle, also to be used for the field coils of the linear drive motor. L'in such a linear motor has the advantage that it is a linear synchronous motor that is in operation Principle of the ordinary or the rotary synchronous motor. The coil arrangement of this already known system with a linear synchronous motor is initially illustrated with reference to FIGS. 8 explained in more detail. Two pairs of field coils 16Λ, 16S and 17A 17ß are provided in the lower part of a vehicle 15. The coils 16/4 and \ f> B are located in lateral parts of the vehicle 15 opposite the ground. The coils 17.4 and 175 are attached near the middle of the vehicle, with iliie F.planes perpendicular to the plane of the coils ifJA and If) I! and. On the side of the floor there are floating