CA1037110A - Rectifier controlled electric rotating or traveling field machine - Google Patents
Rectifier controlled electric rotating or traveling field machineInfo
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- CA1037110A CA1037110A CA203,566A CA203566A CA1037110A CA 1037110 A CA1037110 A CA 1037110A CA 203566 A CA203566 A CA 203566A CA 1037110 A CA1037110 A CA 1037110A
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Abstract
ABSTRACT OF THE DISCLOSURE
Drive arrangement consisting of an electrical rotating field or traveling field machine operated with variable angular or linear speed from an A.C. or D.C. current source through rectifier comprising a rectifier for energizing the windings of the electrical machine which produces three A.C. currents, each with a superimposed D.C. current, forming a three phase system, the stator winding of the electrical rotating field machine being so built that each of the two winding conductors or conducting rods in a slot carries an A.C. current with a superimposed D.C. current with the D.C. current components flowing in opposite directions and the ampere turns produced by the D.C. current components cancelling each other out, the A.C. current components, however, cooperating to produce a rotating or traveling field.
Drive arrangement consisting of an electrical rotating field or traveling field machine operated with variable angular or linear speed from an A.C. or D.C. current source through rectifier comprising a rectifier for energizing the windings of the electrical machine which produces three A.C. currents, each with a superimposed D.C. current, forming a three phase system, the stator winding of the electrical rotating field machine being so built that each of the two winding conductors or conducting rods in a slot carries an A.C. current with a superimposed D.C. current with the D.C. current components flowing in opposite directions and the ampere turns produced by the D.C. current components cancelling each other out, the A.C. current components, however, cooperating to produce a rotating or traveling field.
Description
1037~0 BACKGROUND OF THE INVENTION
Field of the Invention:
'rhe invention concerns a drive arrangement consisting of an electric rotating or traveling field machine of variable angular or linear speed energized from an A. C. or D. C. source by rectifier.
Description of the Prior Art:
Among the numerous electric motor drives with variable speed there are instances of use requiring three phase motors with the simplest possible rotor construction. To this class belong asynchronous machines with squirrel cage rotors and homopolar synchronous machines, the speed of which is adjustable or controllable by the frequency and voltage regulation of a transverter. The energizing of such three phase drives with variable frequency and voltage through rectifiers with D. C. interstage or through direct transverters is known.
The operation of asynchronous machines entails a high cost (a) for self commutating rectifiers with a D. C. current or voltage interstage because of the double energy transformation in the converter and inverter as well as the energy storage in the intermediate filter and (b) for direct transverters because of the need for antiparallel rectifiers in every winding lead. Beslde the highe~t frequency attainable presently by mean of _z_ ~'"
' 1037~0 high power direct transverters is limited.
Homopolar synchronous machines, furthermore, require an excitation winding in addition to the three phase stator winding.
SUMMARY OF TlIE INVENTION
The problem faced by the invention is that of reducing the cost of the said rectifiers feeding rotating field and traveling field machines.
An additional problem for the invention is, in connection with electric traveling field machines intended for driving magnetic suspension vehicles, to combine in a single winding the ordinarily separate windings for traction in synchronous machines and the excitation winding for the guiding and support magnets. This single winding is to be fed from a common rectifier control permitting the two functions of propelling and of guiding or supporting the vehicle to be controlled independently of one another over wide ranges.
As the solution of the first mentioned problem, it is provided according to the invention that the windings of the electrical machine are fed by a rectifier producing three D. C. biased A. C. currents forming a three phase system. ~he stator winding of the machine is a multi-layer one so constructed $hat each of the two winding strands or conductor rods laid in a slot carries a D. C. biased A, C. current with the D. C.
components of the currents flowing in opposite directions and the ampere-turns produced by the D. C. current components of the two winding strands or conductor rods in every slot cancelling each other out but with the A. C.
components cooperating to produce a rotating or traveling field.
It is understandable that such a machine, because of the non-torque-producing D. C. currents, must be poorer in efficiency as well as in output than an electrical machine of conventional construction and must therefore be larger for the same output.
~his extra cost will be made up for, however, because the cost of the transverter driving the electrical machine can be cut to almost half that of the conventional transverter. Before describing the structure of the transverters, made with known components, the various embodiments of the electrical machines conforming with the invention will be described.
~he electrical machine for the drive arrangement according to the invention can be constructed as an asynchronous as well as homopolar synchronous machine.
In a first embodiment of the form of an asynchronous rotating field machine, the stator winding is so constructed that the ampere turns 10371~0 produced by the D. C. current components cancel in the coil end of each pushing side.
In a first variant of this embodiment, the stator winding is a two layer winding. ~his winding can be a three phase winding short pitched by one zone. Here the circulations of the top and bottom layers of a coil are different or belong to different sections.
In a second variant, the stator (primary) winding is three layered with each phase connected to a layer (plane).
In a further development of this embodiment, the coils of each phase are arranged concentrically in one another and the face connections lie in the same plane (layer) as the coil segment lying in the iron. By means of this configuration, off-setting of the coils can be avoided with a further reduction in cost.
In a second embodiment of the electrical machine in accordance with the invention in the form of a homopolar synchronous machine, the coils of the primary winding are each short pitched around a third of a pole pitch so that the D. C. current components in the winding always add in the coil ends of the machine to produce a constant circulation in one direction on one pushing side and in the other on the other side which constitutes the excitation ampere turns by which the machine's armature is magnetized.
~ 1037110 In a further embodiment of the invention intended to solve the second problem, the electrical machine is built, in the above-mentioned arrangement, as an asynchronous traveling field machine for propelling a magnetic suspension vehicle. ~he winding is laid in slots running perpendicularly to the length of the machine in the middle leg of a yoke with a U, E or V shaped cross section so that the D. C.
current components of the winding currents are in the same direction in the coil end producing a constant coil and flux and a steady flux through the iron which exerts a supporting force on the secondary part of the travel-ing field machine.
If a one sided asynchronous linear motor having a secondary part without a closed magnetic circuit is driven, then, with suitable dimensioning, there is possible an electrodynamic suspension of the vehicle because of electrodynamic repulsion between the primary and secondary parts as long as the frequency of the currents induced in the secondary part is sufficiently high. For stable tractive operation, this electrodynamic suspension requires a regulated rectifier output unit. rhis already exists in the form of the energizing rectifiers in the new arrange-ment so that the cost for the drive arrangement described is reduced in comparison with other solutions.
~0371~1~
By another feature of the invention, the winding can be made a two layered lap or wave winding with pitch shortened by one third the pole pitch.
In a further embodiment of the invention, the asynchronous traveling field machine has a multiple wave winding as a full pitch two layer winding of doubled zone width.
In a further embodiment of the invention, the winding is a three layer form with coils of different widths arranged concentrically with the coils of one phase always lying in the same plane and the portions of the slots not occupied by conductors being made into cooling ducts.
~he coil groups in the middle are made full pitched. ~he advantage of this configuration is narrower coil ends and the simpler fabrication of the coils.
In accordance with a further characteristic of the invention, there is located opposite the yoke, E shaped in cross section, of the traveling field machine a magnetic short circuiter, a conducting plate and a support rail with an air gap between the yoke and the magnetic short cir-cuiter, conducting plate and support rail.
~he width of the conducting plate is substantially equal to the distance between the inner edges of the two outer legs. ~he width of the support rail is substantially equal to the distance between the outer edges of the two outer legs. ~he width of the magnetic short circuiter is about that of the middle leg.
In a one-sided configuration of an asynchronous linear motor with secondary part and magnetic short circuiter there is effective along with the electrodynamic repulsion forces a greater electromagnetic attrac-tive force which contributes, to some extent at least, to supporting the vehicle. Stable support and guidance of the vehicle requires regulation of the electromagnetic attraction which can be effected with the help of the present rectifiers.
In the forms of the invention proposed herein, in addition to the savings on the rectifier in the configuration, savings are permitted both on the support winding and on the control elements for energizing the support and guiding magnets.
There are known to arise in one sided traveling field machines, in addition to the force components in the direction of travel, force ` components perpendicular to them which in asynchronous machines the secondary part of which has a magnetic short circuiter, act as attractive forces between the secondary and primary parts.
10371~0 With decreasing separation (air gaps) these attractive forces decrease. The air gap must therefore always be held constant by suitable rr.eans, for example, by mechanical or electromagnetic control.
In a paper by H. Kemper printed in the ETZ-A 1953, pps. 10-15, under the title "Railroad Cars with Electromagnetic Suspension", there are described cars driven by traveling field machines which support and guide the car by means of separate support and guiding magnets or even by additional support windings on the machine.
In contrast to the known configurations, the arrangement of the invention produces a reduction in cost which is achieved on the one hand by sparing the support winding and on the other by the sparing of a separate support current control element. By merging the control elements for armature three phase current and D. C. support current, or support and excitation D. C. current, into an undulatory current control element there is obtained a further simplication when, as in the arrangement of the invention, the D. C. current component is greater than the amplitude of the A. C. current component since here the cost of the rectifier may be sub-stantially reduced.
Systems suited for electromagnetic position control require, in order to achieve sufficiently fast changes in magnetic flux, a large enough over-excitation voltage. With a separate excitation arrangement, the cost of the rectifier for the support magnet circuit is thereby determined.
In the combined, undulatory current fed drive and support desi gn, the reserve voltage necessary for overexcitation is present at no extra cost, since the transverter producing the traveling field can also cause a fast enough flux change for the steady field.
In a further embodiment of the solution of the second part of the prop~ ed problem, the electrical machine, in the above mentioned arrange-ment is constructed as a synchronous, homopolar, traveling field machine with a primary part and a reaction bar opposite it and provided as the drive of a magnetic suspension vehicle. For this the winding is so con-structed that the D. C. current components of the winding currents flow in the same direction in the coil end producing a coil and circulation which forces a steady flux through the iron which serves as excitation for the machine. ~he force exerted by the magnetic field of the steady circulation is, in addition, used for support of the suspension vehicle. ~he mentioned steady circulation acts therefore as excitation circulation which produces through the magnetic conductivity variations of the reaction bar a modulated excitation traveling field and the mentioned additional force for support of the suspension vehicle.
In a ordance with a further characteristic oS the invention, the ~ -10-l03nl0 winding of the synchronous traveling field machine is constructed as a full pitch two layer winding of double zone width.
In a further embodiment of the invention, the homopolar, synchronous, traveling field machine has a full pitch three layer winding of double zone width in the middle. ~he advantage of this configuration is, as in the aforementioned winding for an asynchronous traveling field machine, a reduced width of the coil ends and simpler fabrication of the coils.
According to another characteristic of the inventio,n, the homo-polor, synchronous, traveling field machine has two armatures, one on each side of the reaction bars, each with its separate winding and con-nected through a U shaped magnetic yoke. By separate control of the D. C. current components of the currents in the two windings, surer guid-ing of the reaction rail in the middle of the gap between the two armatures is possible.
; In another embodiment of the invention, the primary part of the electrical traveling field machine has an E shaped cross section with the winding slots cut in the top of the middle leg at right angles to the length of the machine. In this arrangement with an E shaped cross section, ao of the prir.~ar art, by control of the excitation and therefore the 10371~0 attractive force between the primary part and yoke on one side and reaction bar on the other, constant distance of the latter can be achieved and the drive arrangement supports the vehicle.
In a further embodiment of the invention, the primary part of the electrical traveling field machine has a U shaped cross section with slots in the top sides of both outer legs substantially perpendicular to the length of the machine. In the slots are laid two separate windings. In this con-figuration, an additional leakage barrier can be located between the two winding legs.
In this arrangement an additional possibility of controlling the vehicle position is provided by separate regulation of the D. C. current components of the currents flowing in the two armatures.
In a further embodiment of the invention, the primary part has a V shaped cross section with the faces of the reaction rail opposite the legs of the primary part perpendicular to the length of the machine. ~he surfaces of the V shaped legs next to these faces have about the same slope and the winding slots in the legs have a uniform depth. ~he slope angle of the faces of the V shaped legs and the opposed faces of the reaction rails is determined the ratio of the required guiding and supporting forces.
1037~L10 In all the configurations described above, the structure of the primary part, or the leg of it carrying the winding, can be in the form of a series of lamination stacks of the width of a tooth and the winding can be laid in the gaps between the teeth. In the above described arrangement, it does not matter whether the reaction rail or the primary structure is stationary or attached to the vehicle.
I'he energizing of the three winding coils of the above described asynchronous or synchronous rotating field machines or the asynchronous or homopolar synchronous traveling field types can be effected in each case in conformity with the invention with a unidirectional rectifier control unit.
In a special configuration, the energizing rectifier arrangement consists of three controlled three phase rectifiers in a center point connect-ion, and an additional controlled three phase rectifier with reversed con-ducting direction connected between the neutral point of the star connected drive motor and the terminals of the secondary windings, also star connected , of the rectifier.
In a further embodiment of the invention, two electrical machines are connected to the terminals of the star connected output of the rectifier transformer, each by way of three three phase rectifiers with opp~site con-ducting directions, these machines being star connected with a common ne utral.
1037~0 In another embodiment of the invention, the rectifier for each winding coil is a unidirectional rectifier control unit.
In a special configuration of the invention, the rectifier for each winding coil is a 3n pulsed rectifier bridge circuit fed by a separate winding of a rectifier transformer, n being an integer.
In a further embodiment, the rectifier for each winding coil is a separate 3n pulsed rectifier with its like phase inputs connected in parallel. I'he outputs of each rectifier are connected to the two ends of one of the winding coils, the latter being electrically isolated from one another. ~he like phase inputs of the rectifier are connected to a three phase line.
~he control of the three phase rectifiers is appropriately effected in such a way that the D. C. current component of the winding cur-rent is greater than the amplitude of the A. C. component.
BRIEF DESCRIP~IC)N OF ~HE DRAWINGS
A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:
FIGURE 1 is a winding diagram for a conventional rotating field machine with full pitched two layer winding, .FIGURE 2 is a winding diagram for an asynchronous rotating field machine according to the invention with two layer winding, FIGURE 3 is a winding diagram for an asynchronous rotating field machine according to the invention with three layer winding, FIGURE 4 is a winding diagram for a homopolar synchronous machine in accordance with the invention, FIGURE 5 is a diagram of a two layer winding for an asynchron-ous or homopolar synchronous traveling field machine, FIGUR.E 6 is the diagram for a three layer winding of an asyn-chronous or homopolar synchronous traveling field machine, FIGURE 7 is a diagram of the distribution of the steady circulation in an asynchronous traveling field machine, FIGURE 8 is a diagram for the distribution of the steady circulatio:
over the length of a synchronous traveling field machine, FIGURE 9 is an asynchronous traveling field machine according to the invention in cross section, FIGURE 10 is a synchronous homopolar traveling field machine with U formed primary part and two windings in cross section, FIGURE 11 is a cross section of a synchronous homopolar travel-ing field machine with E shaped cross section in the primary part, ~037110 FIGUR.E 12 is a section through a traveling field machine with U shaped primary part and leakage barrier with two separate windings per leg, FIGURE 13 is the same type of traveling field machine but with S a primary part of V shaped cross section, FIGURE 14 is a traveling field machine in which the legs with the windings are divided into separate lamination stacks, FIGUR.E 15 is a block diagram for the arrangement conforming with the invention, FIGURE 16 is a rectifier arrangement for energizing the arrange-ment of the invention with three controlled three phase rectifiers in center point connection, FIGURE 17 is a rectifier arrangement for energizing the traveling field machines with two controlled three phase rectifiers each of which energizes a traveling field machine, with the star connected machines having a common neutral, : FIGURE 18 is a schematic of a transverter conforming with the invention with a unidirectional rectifier control element, FIGURE 19 is a schematic of a transverter with a rectifier bridge circuit having separate transformer windings for each leg of the bridg and 10371~0 FIGURE 20 is a transverter circuit with common inputs to the rectifier bridges.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMEN~S
In the drawings, the winding layers in a two layer configuration are denoted by a, b, and in a three layer configuration by c, d, e.
The winding coils are deno ted by u-u, v-v and w-w. Further, 3 denotes a zone width, 4 a double pole pitch, 5 the part of the coils passing be-tween the lamination stacks and 6 the face connectors. The arrows in the face connections show the directions of the D. C. current components flowing through them.
In the conventional winding shown in Figure 1, the coil width equals the pole pitch.
In the two layer winding of an arrangement conforming with the invention shown in Figure 2, the coil width is short pitched by a third amounting therefore to two thirds the pole pitch. As appears from Figure
Field of the Invention:
'rhe invention concerns a drive arrangement consisting of an electric rotating or traveling field machine of variable angular or linear speed energized from an A. C. or D. C. source by rectifier.
Description of the Prior Art:
Among the numerous electric motor drives with variable speed there are instances of use requiring three phase motors with the simplest possible rotor construction. To this class belong asynchronous machines with squirrel cage rotors and homopolar synchronous machines, the speed of which is adjustable or controllable by the frequency and voltage regulation of a transverter. The energizing of such three phase drives with variable frequency and voltage through rectifiers with D. C. interstage or through direct transverters is known.
The operation of asynchronous machines entails a high cost (a) for self commutating rectifiers with a D. C. current or voltage interstage because of the double energy transformation in the converter and inverter as well as the energy storage in the intermediate filter and (b) for direct transverters because of the need for antiparallel rectifiers in every winding lead. Beslde the highe~t frequency attainable presently by mean of _z_ ~'"
' 1037~0 high power direct transverters is limited.
Homopolar synchronous machines, furthermore, require an excitation winding in addition to the three phase stator winding.
SUMMARY OF TlIE INVENTION
The problem faced by the invention is that of reducing the cost of the said rectifiers feeding rotating field and traveling field machines.
An additional problem for the invention is, in connection with electric traveling field machines intended for driving magnetic suspension vehicles, to combine in a single winding the ordinarily separate windings for traction in synchronous machines and the excitation winding for the guiding and support magnets. This single winding is to be fed from a common rectifier control permitting the two functions of propelling and of guiding or supporting the vehicle to be controlled independently of one another over wide ranges.
As the solution of the first mentioned problem, it is provided according to the invention that the windings of the electrical machine are fed by a rectifier producing three D. C. biased A. C. currents forming a three phase system. ~he stator winding of the machine is a multi-layer one so constructed $hat each of the two winding strands or conductor rods laid in a slot carries a D. C. biased A, C. current with the D. C.
components of the currents flowing in opposite directions and the ampere-turns produced by the D. C. current components of the two winding strands or conductor rods in every slot cancelling each other out but with the A. C.
components cooperating to produce a rotating or traveling field.
It is understandable that such a machine, because of the non-torque-producing D. C. currents, must be poorer in efficiency as well as in output than an electrical machine of conventional construction and must therefore be larger for the same output.
~his extra cost will be made up for, however, because the cost of the transverter driving the electrical machine can be cut to almost half that of the conventional transverter. Before describing the structure of the transverters, made with known components, the various embodiments of the electrical machines conforming with the invention will be described.
~he electrical machine for the drive arrangement according to the invention can be constructed as an asynchronous as well as homopolar synchronous machine.
In a first embodiment of the form of an asynchronous rotating field machine, the stator winding is so constructed that the ampere turns 10371~0 produced by the D. C. current components cancel in the coil end of each pushing side.
In a first variant of this embodiment, the stator winding is a two layer winding. ~his winding can be a three phase winding short pitched by one zone. Here the circulations of the top and bottom layers of a coil are different or belong to different sections.
In a second variant, the stator (primary) winding is three layered with each phase connected to a layer (plane).
In a further development of this embodiment, the coils of each phase are arranged concentrically in one another and the face connections lie in the same plane (layer) as the coil segment lying in the iron. By means of this configuration, off-setting of the coils can be avoided with a further reduction in cost.
In a second embodiment of the electrical machine in accordance with the invention in the form of a homopolar synchronous machine, the coils of the primary winding are each short pitched around a third of a pole pitch so that the D. C. current components in the winding always add in the coil ends of the machine to produce a constant circulation in one direction on one pushing side and in the other on the other side which constitutes the excitation ampere turns by which the machine's armature is magnetized.
~ 1037110 In a further embodiment of the invention intended to solve the second problem, the electrical machine is built, in the above-mentioned arrangement, as an asynchronous traveling field machine for propelling a magnetic suspension vehicle. ~he winding is laid in slots running perpendicularly to the length of the machine in the middle leg of a yoke with a U, E or V shaped cross section so that the D. C.
current components of the winding currents are in the same direction in the coil end producing a constant coil and flux and a steady flux through the iron which exerts a supporting force on the secondary part of the travel-ing field machine.
If a one sided asynchronous linear motor having a secondary part without a closed magnetic circuit is driven, then, with suitable dimensioning, there is possible an electrodynamic suspension of the vehicle because of electrodynamic repulsion between the primary and secondary parts as long as the frequency of the currents induced in the secondary part is sufficiently high. For stable tractive operation, this electrodynamic suspension requires a regulated rectifier output unit. rhis already exists in the form of the energizing rectifiers in the new arrange-ment so that the cost for the drive arrangement described is reduced in comparison with other solutions.
~0371~1~
By another feature of the invention, the winding can be made a two layered lap or wave winding with pitch shortened by one third the pole pitch.
In a further embodiment of the invention, the asynchronous traveling field machine has a multiple wave winding as a full pitch two layer winding of doubled zone width.
In a further embodiment of the invention, the winding is a three layer form with coils of different widths arranged concentrically with the coils of one phase always lying in the same plane and the portions of the slots not occupied by conductors being made into cooling ducts.
~he coil groups in the middle are made full pitched. ~he advantage of this configuration is narrower coil ends and the simpler fabrication of the coils.
In accordance with a further characteristic of the invention, there is located opposite the yoke, E shaped in cross section, of the traveling field machine a magnetic short circuiter, a conducting plate and a support rail with an air gap between the yoke and the magnetic short cir-cuiter, conducting plate and support rail.
~he width of the conducting plate is substantially equal to the distance between the inner edges of the two outer legs. ~he width of the support rail is substantially equal to the distance between the outer edges of the two outer legs. ~he width of the magnetic short circuiter is about that of the middle leg.
In a one-sided configuration of an asynchronous linear motor with secondary part and magnetic short circuiter there is effective along with the electrodynamic repulsion forces a greater electromagnetic attrac-tive force which contributes, to some extent at least, to supporting the vehicle. Stable support and guidance of the vehicle requires regulation of the electromagnetic attraction which can be effected with the help of the present rectifiers.
In the forms of the invention proposed herein, in addition to the savings on the rectifier in the configuration, savings are permitted both on the support winding and on the control elements for energizing the support and guiding magnets.
There are known to arise in one sided traveling field machines, in addition to the force components in the direction of travel, force ` components perpendicular to them which in asynchronous machines the secondary part of which has a magnetic short circuiter, act as attractive forces between the secondary and primary parts.
10371~0 With decreasing separation (air gaps) these attractive forces decrease. The air gap must therefore always be held constant by suitable rr.eans, for example, by mechanical or electromagnetic control.
In a paper by H. Kemper printed in the ETZ-A 1953, pps. 10-15, under the title "Railroad Cars with Electromagnetic Suspension", there are described cars driven by traveling field machines which support and guide the car by means of separate support and guiding magnets or even by additional support windings on the machine.
In contrast to the known configurations, the arrangement of the invention produces a reduction in cost which is achieved on the one hand by sparing the support winding and on the other by the sparing of a separate support current control element. By merging the control elements for armature three phase current and D. C. support current, or support and excitation D. C. current, into an undulatory current control element there is obtained a further simplication when, as in the arrangement of the invention, the D. C. current component is greater than the amplitude of the A. C. current component since here the cost of the rectifier may be sub-stantially reduced.
Systems suited for electromagnetic position control require, in order to achieve sufficiently fast changes in magnetic flux, a large enough over-excitation voltage. With a separate excitation arrangement, the cost of the rectifier for the support magnet circuit is thereby determined.
In the combined, undulatory current fed drive and support desi gn, the reserve voltage necessary for overexcitation is present at no extra cost, since the transverter producing the traveling field can also cause a fast enough flux change for the steady field.
In a further embodiment of the solution of the second part of the prop~ ed problem, the electrical machine, in the above mentioned arrange-ment is constructed as a synchronous, homopolar, traveling field machine with a primary part and a reaction bar opposite it and provided as the drive of a magnetic suspension vehicle. For this the winding is so con-structed that the D. C. current components of the winding currents flow in the same direction in the coil end producing a coil and circulation which forces a steady flux through the iron which serves as excitation for the machine. ~he force exerted by the magnetic field of the steady circulation is, in addition, used for support of the suspension vehicle. ~he mentioned steady circulation acts therefore as excitation circulation which produces through the magnetic conductivity variations of the reaction bar a modulated excitation traveling field and the mentioned additional force for support of the suspension vehicle.
In a ordance with a further characteristic oS the invention, the ~ -10-l03nl0 winding of the synchronous traveling field machine is constructed as a full pitch two layer winding of double zone width.
In a further embodiment of the invention, the homopolar, synchronous, traveling field machine has a full pitch three layer winding of double zone width in the middle. ~he advantage of this configuration is, as in the aforementioned winding for an asynchronous traveling field machine, a reduced width of the coil ends and simpler fabrication of the coils.
According to another characteristic of the inventio,n, the homo-polor, synchronous, traveling field machine has two armatures, one on each side of the reaction bars, each with its separate winding and con-nected through a U shaped magnetic yoke. By separate control of the D. C. current components of the currents in the two windings, surer guid-ing of the reaction rail in the middle of the gap between the two armatures is possible.
; In another embodiment of the invention, the primary part of the electrical traveling field machine has an E shaped cross section with the winding slots cut in the top of the middle leg at right angles to the length of the machine. In this arrangement with an E shaped cross section, ao of the prir.~ar art, by control of the excitation and therefore the 10371~0 attractive force between the primary part and yoke on one side and reaction bar on the other, constant distance of the latter can be achieved and the drive arrangement supports the vehicle.
In a further embodiment of the invention, the primary part of the electrical traveling field machine has a U shaped cross section with slots in the top sides of both outer legs substantially perpendicular to the length of the machine. In the slots are laid two separate windings. In this con-figuration, an additional leakage barrier can be located between the two winding legs.
In this arrangement an additional possibility of controlling the vehicle position is provided by separate regulation of the D. C. current components of the currents flowing in the two armatures.
In a further embodiment of the invention, the primary part has a V shaped cross section with the faces of the reaction rail opposite the legs of the primary part perpendicular to the length of the machine. ~he surfaces of the V shaped legs next to these faces have about the same slope and the winding slots in the legs have a uniform depth. ~he slope angle of the faces of the V shaped legs and the opposed faces of the reaction rails is determined the ratio of the required guiding and supporting forces.
1037~L10 In all the configurations described above, the structure of the primary part, or the leg of it carrying the winding, can be in the form of a series of lamination stacks of the width of a tooth and the winding can be laid in the gaps between the teeth. In the above described arrangement, it does not matter whether the reaction rail or the primary structure is stationary or attached to the vehicle.
I'he energizing of the three winding coils of the above described asynchronous or synchronous rotating field machines or the asynchronous or homopolar synchronous traveling field types can be effected in each case in conformity with the invention with a unidirectional rectifier control unit.
In a special configuration, the energizing rectifier arrangement consists of three controlled three phase rectifiers in a center point connect-ion, and an additional controlled three phase rectifier with reversed con-ducting direction connected between the neutral point of the star connected drive motor and the terminals of the secondary windings, also star connected , of the rectifier.
In a further embodiment of the invention, two electrical machines are connected to the terminals of the star connected output of the rectifier transformer, each by way of three three phase rectifiers with opp~site con-ducting directions, these machines being star connected with a common ne utral.
1037~0 In another embodiment of the invention, the rectifier for each winding coil is a unidirectional rectifier control unit.
In a special configuration of the invention, the rectifier for each winding coil is a 3n pulsed rectifier bridge circuit fed by a separate winding of a rectifier transformer, n being an integer.
In a further embodiment, the rectifier for each winding coil is a separate 3n pulsed rectifier with its like phase inputs connected in parallel. I'he outputs of each rectifier are connected to the two ends of one of the winding coils, the latter being electrically isolated from one another. ~he like phase inputs of the rectifier are connected to a three phase line.
~he control of the three phase rectifiers is appropriately effected in such a way that the D. C. current component of the winding cur-rent is greater than the amplitude of the A. C. component.
BRIEF DESCRIP~IC)N OF ~HE DRAWINGS
A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:
FIGURE 1 is a winding diagram for a conventional rotating field machine with full pitched two layer winding, .FIGURE 2 is a winding diagram for an asynchronous rotating field machine according to the invention with two layer winding, FIGURE 3 is a winding diagram for an asynchronous rotating field machine according to the invention with three layer winding, FIGURE 4 is a winding diagram for a homopolar synchronous machine in accordance with the invention, FIGURE 5 is a diagram of a two layer winding for an asynchron-ous or homopolar synchronous traveling field machine, FIGUR.E 6 is the diagram for a three layer winding of an asyn-chronous or homopolar synchronous traveling field machine, FIGURE 7 is a diagram of the distribution of the steady circulation in an asynchronous traveling field machine, FIGURE 8 is a diagram for the distribution of the steady circulatio:
over the length of a synchronous traveling field machine, FIGURE 9 is an asynchronous traveling field machine according to the invention in cross section, FIGURE 10 is a synchronous homopolar traveling field machine with U formed primary part and two windings in cross section, FIGURE 11 is a cross section of a synchronous homopolar travel-ing field machine with E shaped cross section in the primary part, ~037110 FIGUR.E 12 is a section through a traveling field machine with U shaped primary part and leakage barrier with two separate windings per leg, FIGURE 13 is the same type of traveling field machine but with S a primary part of V shaped cross section, FIGURE 14 is a traveling field machine in which the legs with the windings are divided into separate lamination stacks, FIGUR.E 15 is a block diagram for the arrangement conforming with the invention, FIGURE 16 is a rectifier arrangement for energizing the arrange-ment of the invention with three controlled three phase rectifiers in center point connection, FIGURE 17 is a rectifier arrangement for energizing the traveling field machines with two controlled three phase rectifiers each of which energizes a traveling field machine, with the star connected machines having a common neutral, : FIGURE 18 is a schematic of a transverter conforming with the invention with a unidirectional rectifier control element, FIGURE 19 is a schematic of a transverter with a rectifier bridge circuit having separate transformer windings for each leg of the bridg and 10371~0 FIGURE 20 is a transverter circuit with common inputs to the rectifier bridges.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMEN~S
In the drawings, the winding layers in a two layer configuration are denoted by a, b, and in a three layer configuration by c, d, e.
The winding coils are deno ted by u-u, v-v and w-w. Further, 3 denotes a zone width, 4 a double pole pitch, 5 the part of the coils passing be-tween the lamination stacks and 6 the face connectors. The arrows in the face connections show the directions of the D. C. current components flowing through them.
In the conventional winding shown in Figure 1, the coil width equals the pole pitch.
In the two layer winding of an arrangement conforming with the invention shown in Figure 2, the coil width is short pitched by a third amounting therefore to two thirds the pole pitch. As appears from Figure
2, the D. CO current component in one layer of the winding in the slot flows in one direction, and that in the other in the opposite direction so that the D. C. magneti~ation within the iron core cancels out. The same holds true for the coil ends in which the D. C. currents flow in different direction~. -17-10371iO
Part A of the figures shows the distribution of the winding turns in zone 3. Part B of the figures shows the corresponding winding schematic with each coil group in zone 3 being represented by only one coil. ~he coil sides 1 from the top layer a and the sides 2 fo~m the bottom layer b.
In the three layer winding for an asynchronous rotating field machine shown in Figure 3, as in the winding arrangement of Figure 2, the coils have the same width. Since each coil lies in a single plane, there are substantial simplifications in the coil end resulting in lower material and labor costs. However, this winding requires greater slot depth than the arrangement of Figure 2 since the slots are filled only to two thirds of their depth. I'he unused spaces in the slots can be used as cooling channels so that better cooling is achieved and heavier loading of the machine is permissible.
The two layer winding for a homopolar synchronous rotating or traveling field machine or even for an asynchrnous traveling field machine shown in Figures 4 and 5 cancels out the D. C. magnetization inside the iron only. The D. C. current components in the coil ends all have the same direction and produce the ampere turns required for the excitation field as well as the necessary force for supporting the vehicle.
The same is true also for the three layer winding shown in 1~;17110 Figure 6 with c~ils of different widths arranged concentrically inside one another and made full pitched with double zone width on the average.
Here, as already mentioned, there are special advantages in the structure of the coil end.
In the cross sections of linear motors shown in Figures 9 to 14, the lamination stacks receiving the winding are denoted by 21, the reaction bars by 22, the winding by 23 and the yoke by 25.
In the drawings of Figures 10 and 11 for synchronous homopolar traveling field machines, an additional support winding 24 is shown in dashed lines and must be provided in prior art machines. In the traveling field machines of the invention, this winding 24 is not required. Further ref-erence symbols will be explained in the description of the individual figures.
In the section of an asynchronous linear machine conforming with the invention as shown in Figure 9, the primary part is E shaped in cross section and consists of a U shaped yoke 25 plus a middle leg 34, in the slots of which, running across the length of the primary part, the winding, a three layer one in the example, is laid. The secondary part is located across the airgap 28 from the yol~e 25. It consists of the support bar 29, the magnetic short circuiter 30 and a conducting plate 31.
The steady flux passes through the yoke 25, the air gap 28 and the support ~10371iO
bars 29 across the direction of travel. The flux of the magnetic traveling field runs either in the plane in the travel direction or across the direction of travel like the steady flux. In this latter case the yoke 25 and support bar 29 are laminated.
The circuit connections required for multiple wave windings are denoted by 32 and, like the windings, lie in the three layers c, d, e outside the yoke 25. In this arrangement part of the D. C. flux penetrates the yoke 25 as leakage flux of the active region denoted by 5. Magnetic satur-ation of the active part does not occur, howeverJ because of the low in-duction of the traveling field.
This asynchronous drive arrangement, which serves simultan-eously for controlled electromagnetic support and/or guidance, posses, for example, a multiple wave winding such as a full pitch two layer winding with double zone width as in Figure 1 or such as a three layer winding with like shaped coil groups which are full pitch on the average in Figure 2.
These windings have a circulation acting in the same direction at both coil ends 6. By independen t control of the D. C. current components of the winding currents, it is then possible to control or regulate the forces necessary for electrical suspension separately from the tractive 2 0 forces .
It should also be pointed out that in the boundary regions, and thus in the beginning and end regions of the windings shown in Figures 1 to 6, not every coil conductor carrying a D. C. current faces another with oppositely flowing D. C. current so that the D. C. circulation in the slot region does not completely cancel out.
In Figure 7, is plotted the D. C. current distribution A= and the steady circulation _ over the length of an asynchronous linear motor in the direction of motion. This additional steady circulation can be taken care of by suitable compensation coils which are provided at the ends of the machine for windings of asynchronous linear motors. This can be effected, for example, by a coil group of V conductors in the arrangement of Figure 3, full pitched with around two zone widths.
In Figure 8, the D. C. current distribution A= and the steady circulation ;F= are likewise plotted over the length of the machine for a homopolar synchronous traveling field machine. In the traveling field machines of the synchronous homopolar configuration shown in Figures 10 to 14, there is produced, as appears from Figure 8, a steady circulation ~_ running the length of the machine as a result of the D. C. current slot circulation of the beginning and end regions of the winding and the D. C. coil end circulation. This acts as excitation circulation and, by the fluctuations in magnetic susceptibility of the reaction rail 22, produces a modulated traveling excitation field.
Examples of embodiments of linear homopolar traveling field machines are shown in Figures 10 to 14.
In the examples in Figures 10 and 11, only about a pole pitch long region of higher magnetic conductance of the reaction rails 22 is shown. The gaps between the illustrated parts of the reaction rail are filled with a nonmagnetic material, not shown, in the drawi ng, which mechanically bonds the two regions of the reaction rail 22. The sections in the drawings of Figures 8 and 9 only show the region of higher magnetic conductance .
In Figure 10, is shown an exan ple of a homopolar synchronous traveling field machine conforming with the invention with two arma$ures 21 arranged one on each side of the reaction rail 22 and connected by a magnetic yoke 25. The attractive forces acting between the reaction rail 22 and armatures 21 in such an arrangement balance out only in a completely symmetric condition. By independnent control of the D. C.
current components of the two armature currents, reliable guidance of the reaction rail 22 halfway between the two armatures is possible.
Figure 11 shows a drive with armature 21 located on one side of reaction rail 22, the magnetic return path of which is through a yoke 25. In this E shaped unilateral arrangement, by regulation of the excitation according to the invention and therefore the attractive force between armature and yoke on one hand and reaction rail on the other, separation can be maintained constant while at the same time the vehicle is supported.
A further configuration of the homopolar synchronous motor of the invention is shown in Figure 12. Here there are two armatures 21 connected by a yoke 25 to produced a U shaped arrangement which is excited by the steady fields of the coil ends 6, the magnetic circuit of which is closed through air gaps and reaction rail 22. In this U shaped arrangement, according to the invention, the force of attraction to the reaction rail 22 can be regulated for support of the vehicle.
If the arrangement of Figure 12 is completed with a leakage barrier 33, then, by independent regulation of the excitation of both armatures 21, there is an additional capability for controlling the vehicle position.
A further embodiment of the homopolar synchronous motor of the inventim i he V Rhaped arrangement of the two armatures 21 shown 10;17~10 in Figure 13 which enables the supporting and guiding of a vehicle. The slope angle ~ of the pole faces of the armatures 21 and the pole faces of the reaction rail 22 is determined by the ratio of the required guidance and support forces.
In all these arrangements it makes no difference as far as the invention is concerned whether the reaction rail 22 or the armature arrangement is stationary or attached to the vehicle.
In Figure 14isan E shaped unilateral arrangement of an armature 21 with yoke 25 of a homopolar synchronousmachine in which the active part 5 or armature 21 with the yoke 25 is divided up into a series of separate lamination stacks 26 of the width of a tooth between which the winding is placed. This division into individual lamination stacks is also possible with the other described homopolar machines of Figures 7 and 8 as well as the asynchronous machine of Figure 4. It offers advantages in fabrication in the production of linear machines.
Figure 15 shows an embodiment of the connection of the drive with a special direct trans verter, e. g., a unidirectional rectifier control unit. The controller 7 furnishes the signal fl for the output frequency of the direct transverter and I for the amplitude of the A. C. current to the , three phase 9 ewave generator 3 which produces the desired values iu, iv and iw corresponding to the three phase system. Block 9 computes from I the desired D. C. current I= to be superimposed. These desired current values are combined at the summing points 10 and control the three current regulators 11 of the three unidirectional rectifier control B units~ of the special direct transverter which is connected to the three phase line of frequency fO, not shown here, and which energizes the three wind-ings 13 of the rotating field machine or traveling field machine, the wind-ings of which are connected according to one of the Figures 2 to 6.
Examples of configurations of rectifier installations for energizing the above described rotating field or traveling field machines are shown in Figures 16 to 20.
The example in Figure 16 consists of three controlled three phase rectifiers 15 with center point connection to which the star connected electrical machine 13 is connected. The neutral point of the electrical machine 13 is connected by way of an additional controlled three phase rectifier 17 with reversed conducting direction to the likewise star connected secondary part of the rectifier transformer. The three phase rectifier is controlled in such a way that the D. C. current compon-ent of the current in the windings is greater than amplitude of the A. C.
component.
In the switching arrangement of the exarnple of Figure 17, two traveling field machines 13 are star connected with a common neutral point. Each of the machines is fed by three controlled three phase recti-fiers with opposite conduction directions and in central point connection with both being driven by the same secondary windings 14 of a rectifier transformer. Instead of the two, possibly mechanically coupled, electrical traveling field machines, use may be made of the two windings of synchronous homopolar traveling field machines as shown in Figures 5 - 7 and 8. In this way, the D, C. current component of the winding currents is prevented from flowing in the secondary winding 14 of the rectifier transformer. This is the reason the thyristors of the two recti-fier bridges are reversed in conducting directions.
In the energizing connection shown in Figure 18 for an electrical machine in accordance with the invention, there are three three pulsed unidirectional rectifier control units each of which has a thyristor group 15 fed by a transformer winding 14, The outputs of the three thyristor control units energize three machine windings 13.
The rectifier arrangement of Figure 19 has three three phase rec-tifier bridges each of which is driven by a special three phase winding of the rectifier transformer. ~he outputs of the three three phase rectifier ~371~Q
bridges 17 drive the winding ends u, x, v, y, w, z of the three windings 13 of the rotating field or traveling field machine.
In the connection shown in Figure 20, the three three phase rectifier bridges 17 are connected independently of one another. This S enables tying together their three phase input terminals R, S, ~ and connecting these points either to the line 19 or to a transformer, in case the line voltage is different from the desired energizing voltage.
The windings 13 of the rotating field or traveling field machine are not connected together in this circuit and so exhibit six terminals u, x, v, y, w, z. ~he ends of each winding are therefore connected to the outputs of one three phase rectifier bridge.
Other rectifier circuits, with the same action as the above-described ones,may obviously be applied equally well to these drive arrangements.
Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.
Part A of the figures shows the distribution of the winding turns in zone 3. Part B of the figures shows the corresponding winding schematic with each coil group in zone 3 being represented by only one coil. ~he coil sides 1 from the top layer a and the sides 2 fo~m the bottom layer b.
In the three layer winding for an asynchronous rotating field machine shown in Figure 3, as in the winding arrangement of Figure 2, the coils have the same width. Since each coil lies in a single plane, there are substantial simplifications in the coil end resulting in lower material and labor costs. However, this winding requires greater slot depth than the arrangement of Figure 2 since the slots are filled only to two thirds of their depth. I'he unused spaces in the slots can be used as cooling channels so that better cooling is achieved and heavier loading of the machine is permissible.
The two layer winding for a homopolar synchronous rotating or traveling field machine or even for an asynchrnous traveling field machine shown in Figures 4 and 5 cancels out the D. C. magnetization inside the iron only. The D. C. current components in the coil ends all have the same direction and produce the ampere turns required for the excitation field as well as the necessary force for supporting the vehicle.
The same is true also for the three layer winding shown in 1~;17110 Figure 6 with c~ils of different widths arranged concentrically inside one another and made full pitched with double zone width on the average.
Here, as already mentioned, there are special advantages in the structure of the coil end.
In the cross sections of linear motors shown in Figures 9 to 14, the lamination stacks receiving the winding are denoted by 21, the reaction bars by 22, the winding by 23 and the yoke by 25.
In the drawings of Figures 10 and 11 for synchronous homopolar traveling field machines, an additional support winding 24 is shown in dashed lines and must be provided in prior art machines. In the traveling field machines of the invention, this winding 24 is not required. Further ref-erence symbols will be explained in the description of the individual figures.
In the section of an asynchronous linear machine conforming with the invention as shown in Figure 9, the primary part is E shaped in cross section and consists of a U shaped yoke 25 plus a middle leg 34, in the slots of which, running across the length of the primary part, the winding, a three layer one in the example, is laid. The secondary part is located across the airgap 28 from the yol~e 25. It consists of the support bar 29, the magnetic short circuiter 30 and a conducting plate 31.
The steady flux passes through the yoke 25, the air gap 28 and the support ~10371iO
bars 29 across the direction of travel. The flux of the magnetic traveling field runs either in the plane in the travel direction or across the direction of travel like the steady flux. In this latter case the yoke 25 and support bar 29 are laminated.
The circuit connections required for multiple wave windings are denoted by 32 and, like the windings, lie in the three layers c, d, e outside the yoke 25. In this arrangement part of the D. C. flux penetrates the yoke 25 as leakage flux of the active region denoted by 5. Magnetic satur-ation of the active part does not occur, howeverJ because of the low in-duction of the traveling field.
This asynchronous drive arrangement, which serves simultan-eously for controlled electromagnetic support and/or guidance, posses, for example, a multiple wave winding such as a full pitch two layer winding with double zone width as in Figure 1 or such as a three layer winding with like shaped coil groups which are full pitch on the average in Figure 2.
These windings have a circulation acting in the same direction at both coil ends 6. By independen t control of the D. C. current components of the winding currents, it is then possible to control or regulate the forces necessary for electrical suspension separately from the tractive 2 0 forces .
It should also be pointed out that in the boundary regions, and thus in the beginning and end regions of the windings shown in Figures 1 to 6, not every coil conductor carrying a D. C. current faces another with oppositely flowing D. C. current so that the D. C. circulation in the slot region does not completely cancel out.
In Figure 7, is plotted the D. C. current distribution A= and the steady circulation _ over the length of an asynchronous linear motor in the direction of motion. This additional steady circulation can be taken care of by suitable compensation coils which are provided at the ends of the machine for windings of asynchronous linear motors. This can be effected, for example, by a coil group of V conductors in the arrangement of Figure 3, full pitched with around two zone widths.
In Figure 8, the D. C. current distribution A= and the steady circulation ;F= are likewise plotted over the length of the machine for a homopolar synchronous traveling field machine. In the traveling field machines of the synchronous homopolar configuration shown in Figures 10 to 14, there is produced, as appears from Figure 8, a steady circulation ~_ running the length of the machine as a result of the D. C. current slot circulation of the beginning and end regions of the winding and the D. C. coil end circulation. This acts as excitation circulation and, by the fluctuations in magnetic susceptibility of the reaction rail 22, produces a modulated traveling excitation field.
Examples of embodiments of linear homopolar traveling field machines are shown in Figures 10 to 14.
In the examples in Figures 10 and 11, only about a pole pitch long region of higher magnetic conductance of the reaction rails 22 is shown. The gaps between the illustrated parts of the reaction rail are filled with a nonmagnetic material, not shown, in the drawi ng, which mechanically bonds the two regions of the reaction rail 22. The sections in the drawings of Figures 8 and 9 only show the region of higher magnetic conductance .
In Figure 10, is shown an exan ple of a homopolar synchronous traveling field machine conforming with the invention with two arma$ures 21 arranged one on each side of the reaction rail 22 and connected by a magnetic yoke 25. The attractive forces acting between the reaction rail 22 and armatures 21 in such an arrangement balance out only in a completely symmetric condition. By independnent control of the D. C.
current components of the two armature currents, reliable guidance of the reaction rail 22 halfway between the two armatures is possible.
Figure 11 shows a drive with armature 21 located on one side of reaction rail 22, the magnetic return path of which is through a yoke 25. In this E shaped unilateral arrangement, by regulation of the excitation according to the invention and therefore the attractive force between armature and yoke on one hand and reaction rail on the other, separation can be maintained constant while at the same time the vehicle is supported.
A further configuration of the homopolar synchronous motor of the invention is shown in Figure 12. Here there are two armatures 21 connected by a yoke 25 to produced a U shaped arrangement which is excited by the steady fields of the coil ends 6, the magnetic circuit of which is closed through air gaps and reaction rail 22. In this U shaped arrangement, according to the invention, the force of attraction to the reaction rail 22 can be regulated for support of the vehicle.
If the arrangement of Figure 12 is completed with a leakage barrier 33, then, by independent regulation of the excitation of both armatures 21, there is an additional capability for controlling the vehicle position.
A further embodiment of the homopolar synchronous motor of the inventim i he V Rhaped arrangement of the two armatures 21 shown 10;17~10 in Figure 13 which enables the supporting and guiding of a vehicle. The slope angle ~ of the pole faces of the armatures 21 and the pole faces of the reaction rail 22 is determined by the ratio of the required guidance and support forces.
In all these arrangements it makes no difference as far as the invention is concerned whether the reaction rail 22 or the armature arrangement is stationary or attached to the vehicle.
In Figure 14isan E shaped unilateral arrangement of an armature 21 with yoke 25 of a homopolar synchronousmachine in which the active part 5 or armature 21 with the yoke 25 is divided up into a series of separate lamination stacks 26 of the width of a tooth between which the winding is placed. This division into individual lamination stacks is also possible with the other described homopolar machines of Figures 7 and 8 as well as the asynchronous machine of Figure 4. It offers advantages in fabrication in the production of linear machines.
Figure 15 shows an embodiment of the connection of the drive with a special direct trans verter, e. g., a unidirectional rectifier control unit. The controller 7 furnishes the signal fl for the output frequency of the direct transverter and I for the amplitude of the A. C. current to the , three phase 9 ewave generator 3 which produces the desired values iu, iv and iw corresponding to the three phase system. Block 9 computes from I the desired D. C. current I= to be superimposed. These desired current values are combined at the summing points 10 and control the three current regulators 11 of the three unidirectional rectifier control B units~ of the special direct transverter which is connected to the three phase line of frequency fO, not shown here, and which energizes the three wind-ings 13 of the rotating field machine or traveling field machine, the wind-ings of which are connected according to one of the Figures 2 to 6.
Examples of configurations of rectifier installations for energizing the above described rotating field or traveling field machines are shown in Figures 16 to 20.
The example in Figure 16 consists of three controlled three phase rectifiers 15 with center point connection to which the star connected electrical machine 13 is connected. The neutral point of the electrical machine 13 is connected by way of an additional controlled three phase rectifier 17 with reversed conducting direction to the likewise star connected secondary part of the rectifier transformer. The three phase rectifier is controlled in such a way that the D. C. current compon-ent of the current in the windings is greater than amplitude of the A. C.
component.
In the switching arrangement of the exarnple of Figure 17, two traveling field machines 13 are star connected with a common neutral point. Each of the machines is fed by three controlled three phase recti-fiers with opposite conduction directions and in central point connection with both being driven by the same secondary windings 14 of a rectifier transformer. Instead of the two, possibly mechanically coupled, electrical traveling field machines, use may be made of the two windings of synchronous homopolar traveling field machines as shown in Figures 5 - 7 and 8. In this way, the D, C. current component of the winding currents is prevented from flowing in the secondary winding 14 of the rectifier transformer. This is the reason the thyristors of the two recti-fier bridges are reversed in conducting directions.
In the energizing connection shown in Figure 18 for an electrical machine in accordance with the invention, there are three three pulsed unidirectional rectifier control units each of which has a thyristor group 15 fed by a transformer winding 14, The outputs of the three thyristor control units energize three machine windings 13.
The rectifier arrangement of Figure 19 has three three phase rec-tifier bridges each of which is driven by a special three phase winding of the rectifier transformer. ~he outputs of the three three phase rectifier ~371~Q
bridges 17 drive the winding ends u, x, v, y, w, z of the three windings 13 of the rotating field or traveling field machine.
In the connection shown in Figure 20, the three three phase rectifier bridges 17 are connected independently of one another. This S enables tying together their three phase input terminals R, S, ~ and connecting these points either to the line 19 or to a transformer, in case the line voltage is different from the desired energizing voltage.
The windings 13 of the rotating field or traveling field machine are not connected together in this circuit and so exhibit six terminals u, x, v, y, w, z. ~he ends of each winding are therefore connected to the outputs of one three phase rectifier bridge.
Other rectifier circuits, with the same action as the above-described ones,may obviously be applied equally well to these drive arrangements.
Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.
Claims (25)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. Drive arrangement consisting of an electric traveling field machine with a primary part and a secondary part driven at a variable angular velocity or linear velocity by a rectifier supplied from an A.C. or D.C. source, the rectifier circuit for each phase winding having a rectifier-driver combination which is controlled in common with other such combinations by a controller so that three A.C.
currents each accompanied by a D.C. current are generated which together create a rotating or traveling field, the stator winding being a multilayer winding so that each of the two winding strands or bars in a slot carries an A.C. current with a superimposed D.C. current with the D.C.
components of the currents flowing in opposite directions and the ampere turns produced by the D.C. current components in the two winding strands or bars in each slot mutually cancelling each other out, the A.C. current components cooperating to produce a traveling field.
currents each accompanied by a D.C. current are generated which together create a rotating or traveling field, the stator winding being a multilayer winding so that each of the two winding strands or bars in a slot carries an A.C. current with a superimposed D.C. current with the D.C.
components of the currents flowing in opposite directions and the ampere turns produced by the D.C. current components in the two winding strands or bars in each slot mutually cancelling each other out, the A.C. current components cooperating to produce a traveling field.
2. Drive arrangement as in Claim 1, wherein the electrical machine is in the form of an asynchronous traveling field machine for driving a magnetic suspension vehicle and the winding is laid in slots running across the long direction of the machine in the middle leg of a yoke with a U, E or V shaped cross section and is so constructed that the D.C. current components of the winding currents are in the same direction in the coil end so that a coil end circulation is produced which generates a steady flux through the iron part which exerts a support-ing force on the secondary part of the traveling field machine.
3. Drive arrangement as in Claim 2, wherein the winding is two layer winding form of a lap or wave winding with the winding pitch shortened by one third of a pole pitch.
4. Drive arrangement as in Claim 2, wherein the asynchronous traveling field machine has a multiple wave winding which is formed as a full pitched two layer winding with doubled zone width.
5. Drive arrangement as in Claim 3, wherein the winding is made as a three layer winding with different width coils lying concentric to one another with the coils of one phase lying in the same plane and the parts of the slots not occupied by conductors being made into cooling ducts.
6. Drive arrangement as in Claim 5, wherein the coil groups are full pitched on the average.
7. Drive arrangement as in Claim 2, wherein opposite the yoke of E shaped cross section of the traveling field machine there is a magnetic circuit closer, a conducting plate and a support rail with an air gap between this and the yoke and the width of the conducting plate about equal to the distance between the inner sides of the two outer legs while the width of the support rail is about equal to the distance between the outer sides of the two outer legs and the width of the magnetic circuit closer is the same as that of the center leg.
8. Drive arrangement as in Claim 7, wherein in the boundary zones of the machine there are additional coils carrying D.C. currents which cancel the effects of steady fields of slots containing only one coil side.
9. Drive arrangement as in Claim 1, wherein the electri-cal machine is in the form of a homopolar synchronous traveling field machine with a primary part and a reaction rail opposite it for driving a magnetic suspension vehicle and the winding is so made that the D.C. current components of the winding currents flow in the same direction in the coil end so that a coil end circulation arises which produces a steady flux through the iron serving as excitation for the machine and the force exerted by the magnetic field of the steady circulation is additionally used for supporting the suspension vehicle.
10. Drive arrangement as in claim 9, wherein the winding of the synchronous traveling field machine is full pitch two layer winding of doubled zone width.
11. Drive arrangement as in Claim 9, wherein the winding of the homopolar synchronous traveling field machine is a three layer winding of full pitch on the average and of doubled zone width.
12. Drive arrangement as in Claim 1, wherein the electric machine is a homopolar synchronous traveling field machine which has two armatures arranged one on each side of a reaction rail, each having its own winding and the two being connected by a U shaped magnetic yoke.
13. Drive arrangement as in Claim 9, wherein the primary part of the electrical traveling field machine has an E
shaped cross section with the slots receiving the winding substan-tially perpendicular to the length of the machine and cut in the top of the center leg.
shaped cross section with the slots receiving the winding substan-tially perpendicular to the length of the machine and cut in the top of the center leg.
14. Drive arrangement as in Claim 9, wherein the primary part of the electrical traveling field machine has a U shaped cross section with both the outer legs having slots which run substantially at right angles with the long direction from the top of the leg inwards and in which two separate windings are laid.
15. Drive arrangement as in Claim 14, wherein in additional leakage barrier is placed between the two legs with windings.
16. Drive arrangement as in Claim 10, wherein the primary part of the electrical traveling field machine has a V shaped cross section with the surfaces of the reaction rail opposite the legs of the primary part running across the long direction of the machine and sloping with respect to the horizontal and the faces of the V
shaped legs next to those surfaces having about the same slope and the slots in the legs receiving the winding having a uniform depth.
shaped legs next to those surfaces having about the same slope and the slots in the legs receiving the winding having a uniform depth.
17. Drive arrangement as in Claim 2, 3 or 4, wherein the primary part or the wound legs of the primary part are divided up into a series of separate lamination stacks of the width of a tooth and the winding is laid in the gaps between these teeth.
18. Drive arrangement as in Claim 1, wherein a unidirectional rectifier control element serves as the rectifier for each of the winding sections.
19. Drive arrangement as in Claim 1, wherein the rectifier driver combination energizing the electrical traveling field machine consists of three controlled three phase rectifiers in center point connection and an additional controlled three phase rectifier with reversed conducting direction is connected between a neutral point of a star connected drive motor and the terminals of a likewise star connected secondary windings of a rectifier transformer.
20. Drive arrangement as in Claim 1, wherein two electrical machines are connected to the terminals of a star connected secondary part of a rectifier transformer, each through three phase rectifiers of opposite conduction directions with these machines being star connected with a common neutral point.
21. Drive arrangement as in Claim 1, wherein a separate 3n pulsed rectifier bridge circuit driven by a separate winding of a rectifier transformer serves as a rectifier for each of the winding sections with n being an integer.
22. Drive arrangement as in Claim 21, wherein the outputs of the three rectifier bridges are connected to the winding ends of the winding sections of the traveling field machine.
23. Drive arrangement as in Claim 1, wherein a separate 3n pulsed rectifier circuit in which n is an integer serves as rectifier for each of the winding sections, the like phase inputs of the former being connected in parallel and the outputs of each rectifier being connected to the two ends of one of the winding sections, the winding sections being electrically isolated from one another.
24. Drive arrangement as in Claim 23, wherein the like phase inputs of the rectifier are connected to a three phase line.
25. Drive arrangement as in Claim 1, wherein the three phase rectifier is controlled in such a way that the D.C. current component of the current flowing in the windings is greater than the amplitude of the A.C. component.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA203,566A CA1037110A (en) | 1974-06-27 | 1974-06-27 | Rectifier controlled electric rotating or traveling field machine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA203,566A CA1037110A (en) | 1974-06-27 | 1974-06-27 | Rectifier controlled electric rotating or traveling field machine |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1037110A true CA1037110A (en) | 1978-08-22 |
Family
ID=4100520
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA203,566A Expired CA1037110A (en) | 1974-06-27 | 1974-06-27 | Rectifier controlled electric rotating or traveling field machine |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1037110A (en) |
-
1974
- 1974-06-27 CA CA203,566A patent/CA1037110A/en not_active Expired
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