Inductively transferring electric energy to a vehicle using consecutive segments which are
operated at the same time
The invention relates to the transfer of electric energy to a vehicle, in particular to a track
bound vehicle such as a light rail vehicle (e.g. a tram) or to a road automobile such as a bus.
A corresponding system comprises an electric conductor arrangement for producing an
alternating electromagnetic field and for thereby transferring electromagnetic energy to the
vehicle. The conductor arrangement comprises a plurality of consecutive segments, wherein
the segments extend in the direction of travel of the vehicle, which is defined by the track or
path of travel. Each segment is combined with an assigned controller (e.g. the control device
of an inverter, which inverts a direct current in a current supply into an alternating current
through the segment, or of an ACJAC converter which, in particular, converts an alternating
current4n an alternating current supply to an alternating current in the respective segment
having a different frequency) adapted to control the operation of the segment independently
of the other segments. The controllers of at least two consecutive segments, which follow
each other in the direction of travel of the vehicle, or follow each other opposite to the
direction of travel, are connected to each other and/or to a central controlling device so that
the at least two consecutive segments can operated at the same time. Each segment
comprises at least three alternating current lines for carrying phases of a multi-phase
alternating current in order to produce the alternating electromagnetic field. Each line carries
a different phase during operation. The alternating current lines of each segment comprise a
plurality of sections which extend transversely to the direction of travel of the vehicle. The
transversely extending sections of the at least three alternating-current lines of each segment
form, if viewed in the direction of travel, a repeating sequence of phases of the alternating
current, while the segment is operated under control of the assigned controller, wherein each
complete repetition of the sequence of phases comprises one transversely extending section
of each phase and the order of the phases is the same in each complete repetition. For
example in the case of a three-phase alternating current having phases U, V, W, the order of
the sequence of the transversely extending sections may be U - V - W - U - V - W (and so
on) and one complete repetition of the sequence of phases is U - V - W.
The invention also relates to a corresponding method of manufacturing the system and to a
corresponding method of operating the system.
Track bound vehicles, such as conventional rail vehicles, mono-rail vehicles, trolley busses
and vehicles which are guided on a track by other means, such as other mechanical means,
magnetic means, electronic means andlor optical means, require electric energy for
propulsion on the track and for operating auxiliary systems, which do not produce traction of
the vehicle. Such auxiliary systems are, for example, lighting systems, heating andlor air
condition system, the air ventilation and passenger information systems. However, more
particularly speaking, the present invention is related to a system for transferring electric
energy to a vehicle which is not necessarily (but preferably) a track bound vehicle. A vehicle
other than a track bound vehicle is a bus, for example. An application area of the invention is
the transfer of energy to vehicles for public transport. However, it is also possible to transfer
energy to private automobiles using the system of the present invention. Generally speaking,
the vehicle may be, for example, a vehicle having an electrically operated propulsion motor.
The vehicle may also be a vehicle having a hybrid propulsion system, e.g. a system which
can be operated by electric energy or by other energy, such as electrochemically stored
energy or fuel (e.g. natural gas, gasoline or petrol).
In order to reduce or avoid electromagnetic fields where no vehicle is driving at a time,
segments of the conductor arrangement may be operated where required only. For example,
the lengths of the segments along the path of travel are shorter than the length of a vehicle ir~
the travel direction and the segments may be operated only if a vehicle is already occupying
the respective region of the path of travel along which the segment extends. In particular,
occupied by a rail vehicle means that the vehicle is driving on the rails along which the
segment extends. For continuous energy transfer while the vehicle is driving, it is proposed
that the segment is switched on (i.e. the assigned controller starts the production of the
alternating current through the segment) before a receiving device of a vehicle for receiving
the transferred energy enters the region of the path of travel along which the segment
extends. However, this means that two or more than two consecutive segments may be
operated at the same time. Otherwise, the energy transfer to the vehicle may be interrupted
and transients of the voltage induced in the vehicle's receiver may be generated.
WO 201 01031 593 A1 describes a system and a method for transferring electric energy to a
vehicle, wherein the system comprises the features mentioned above. However, the
segments are electrically connected in series to each other and there is one inverter at each
interface between two consecutive segments. It is disclosed that switches of the inverters are
controlled to produce the alternating current. Each switch may be controlled by a drive unit
which controls the timing of individual processes of switching on and switching off the switch.
The drive units may be controlled by a controller of the inverter which coordinates the timing
of all drive units. The synchronization of different inverters may be performed by a single
higher-level control device by transferring synchronization signals to each controller of the
inverters to be synchronized. A synchronization link may be provided, which may be a digital
data bus. The link extends along the path of travel of the vehicle and comprises connections
to each controller in order to transfer synchronization signals. In addition, there is also a
connection from each controller to the synchronization link. The reverse connections are
used to transfer signals from the controllers to the synchronization link and thereby to other
controllers which are connected to the synchronization link. One of the controllers being a
master controller at a time outputs synchronization signals via the reverse connection and via
the synchronization link to the other controllers for synchronizing the operation of all
controllers which are operated at a time. If the inverter which is controlled by the master
controller ceases operation another controller takes over the task of being the master
controller. The new master controller outputs synchronization signals via its reverse
connection and via the synchronization link to the other controllers.
According to WO 201 0J031593 A1, synchronization is performed either at a phase shift or
with no phase shift. This means that at opposite ends of one segment or of consecutive
segments inverters are either operated with phase shift or no phase shift and,
correspondingly, an alternating current flows through the phase lines of the segment or
consecutive segments, if there is a phase shift, or no current flows through the phase lines, if
there is no phase shift. As a result, the synchronization disclosed in WO 201 01031 593 A1 is
performed for the sole purpose to either generate an alternating current or not to generate an
alternating current in a segment or in consecutive segments.
It is a disadvantage of this conductor arrangement having consecutive segments which are
connected in series to each other that there is still an electric voltage between the alternating
current phase lines of the segments and a reference potential if the alternating current
carried by the phase lines of the segments is zero. Consequently, it is more difficult to meet
requirements concerning electromagnetic compatibility (EMC). Furthermore, the phase shift
between inverters at opposite ends of a segment or of consecutive segments may not be
exactly zero. As a result, electric currents may flow through the phase lines of the segment(s)
unintentionally.
It is an object of the present invention to provide a system for inductively transferring electric
energy to a vehicle which reduces electric andlor electromagnetic field emissions. It is a
further object to provide a corresponding method of manufacturing the system and a
corresponding method of operating the system.
It is a basic idea of the present invention to provide or use a conductor arrangement
comprising a plurality of consecutive segments which are electrically connected in parallel to
each other. During operation of a segment, the alternating current lines of the respective
segment carry an alternating current in order to produce the alternating electromagnetic field
for inductive energy transfer.
It is an advantage of parallel segments that the voltage between the different alternating
current lines of the segment can be zero while the segment is not operated, e.g. by switching
off the alternating current lines and thereby setting the electric potentials of the alternating
current lines to zero.
The inventors have observed that the way of operating two or more consecutive segments at
the same time also influences the electromagnetic field. In particular, discontinuities of the
electromagnetic field at the interface of two consecutive segments produce undesired
frequency signals in the field itself and in the receiver system of the vehicle which receives
the electromagnetic field. The effect is similar to the effect of a step-like change of an electric
current.
In particular, the interface of two consecutive segments is not constituted by an electric line
or electric lines, but is an area (which may be called transition zone) where the consecutive
segments pass over to each other. As will be described later, it is preferred that there is a
transition zone in the direction of travel, wherein transversely extending sections of
alternating current lines of both consecutive segments are located within the transition zone.
Therefore, it is proposed to operate the two consecutive segments or more than two
consecutive segments, which are operated at the same time, so that the transversely
extending sections of the at least three alternating current lines of the consecutive segments
from a repeating sequence of phases of the alternating current. This repeating sequence of
phases is the same within the extension of the individual segments and in the transition zone
of two consecutive segments. For example, in the case of a three-phase alternating current
having phases U, V, W, the order of the sequence of the transversely extending sections
may be U - V - W - U - V - W.. . (as mentioned above). In case of a four-phase alternating
current having phases U, V, W, X, the order would be U - V - W - X - U - V - W - X ...
Therefore, this order also applies to the transition zones of consecutive segments which are
operated at the same time. Consequently, "repeating sequence" in this description means
that the order of the phases repeats in the same manner. One complete repetition of the
sequence of phases is constituted by one occurrence of each phase of the alternating
current.
As mentioned, the repeating sequence of phases is formed by the transversely extending
sections of the at least three alternating current lines of the consecutive segments.
Consequently, a transversely extending section for carrying a first phase (e.g. phase U) is
followed by a transversely extending section for carrying a second phase (e.g. phase V), the
second transversely extending section is followed by a transversely extending section for
carrying a third phase (e.g. phase W), in case of more than three phases this transversely
extending section is followed by a transversely extending section for carrying a fourth phase
(e.g. phase X) and so on until a transversely extending section for carrying the last,
remaining phase of the multi-phase alternating current. In the above example of three
phases U, V, W, the last phase is W. In the above example of four phases U, V, W, X, the
last phase is X. The transversely extending section for carrying the last phase is followed by
a second transversely extending section for carrying the first phase (e.g. phase U), followed
by a second transversely extending section for carrying the second phase (e.g. phase V),
and so on. In the case of three phases of the alternating current, every third transversely
extending section carries the same phase during operation and this also applies to the
transition zones of consecutive segments.
In particular, the following is proposed: A system for transferring electric energy to a vehicle,
in particular to a track bound vehicle such as a light rail vehicle or to a road automobile,
wherein
- the system comprises an electric conductor arrangement for producing an alternating
electromagnetic field and for thereby transferring the energy to the vehicle,
- the conductor arrangement comprises a plurality of consecutive segments, wherein the
segments extend in the direction of travel of the vehicle, which is defined by the track or
path of travel,
- each segment is combined with an assigned controller adapted to control the operation
of the segment independently of the other segments,
- the controllers of at least two consecutive segments, which follow each other in the
direction of travel of the vehicle, or which follow each other opposite to the direction of
travel, are connected to each other and/or to a central controlling device so that the at
least two consecutive segments can operated at the same time,
- each segment comprises at least three alternating current lines for carrying phases of a
multi-phase alternating current in order to produce the alternating electromagnetic field,
- the consecutive segments are electrically connected in parallel to each other to a current
SLJPP~Y 9
- the alternating current lines of each segment comprise a plurality of sections which
extend transversely to the direction of travel of the vehicle,
- the transversely extending sections of the at least three alternating-current lines of each
segment form, if viewed in the direction of travel, a repeating sequence of phases of the
alternating current, while the segment is operated under control of the assigned
controller, wherein each complete repetition of the sequence of phases comprises one
transversely extending section of each phase and the order of the phases is the same in
each complete repetition,
- the controllers of the at least two consecutive segments and/or the central controlling
device arelis adapted to operate the at least two consecutive segments, so that the
repeating sequence of phases continues from one segment to the consecutive segment,
wherein the order of the phases is the same in the at least two consecutive segments
and in each transition zone of two of the at least two consecutive segments.
In addition a method of operating a system is proposed for transferring electric energy to a
vehicle, in particular to a track bound vehicle such as a light rail vehicle or to a road
automobile, wherein
- an electric conductor arrangement is operated for producing an alternating
electromagnetic field and for thereby transferring the energy to the vehicle,
- a plurality of consecutive segments of the conductor arrangement is operated, wherein
the segments extend in the direction of travel of the vehicle, which is defined by the track
or path of travel,
- for each segment, an assigned controller is operated to control the operation of the
segment independently of the other segments,
- the controllers of at least two consecutive segments, which follow each other in the
direction of travel of the vehicle, or which follow each other opposite to the direction of
travel, are operated in connection with each other and/or with a central controlling device
so that the at least two consecutive segments are operated at the same time,
- in each segment, at least three alternating current lines carry phases of a multi-phase
alternating current in order to produce the alternating electromagnetic field,
- the consecutive segments are electrically connected in parallel to each other to a current
supply 1
- the alternating current lines of each segment comprise a plurality of sections which
extend transversely to the direction of travel of the vehicle,
- the transversely extending sections of the at least three alternating-current lines of each
segment form, if viewed in the direction of travel, a repeating sequence of phases of the
alternating current, while the segment is operated under control of the assigned
controller, wherein each complete repetition of the sequence of phases comprises one
transversely extending section of each phase and the order of the phases is the same in
each complete repetition,
- the controllers of the at least two consecutive segments andlor the central controlling
device operate(s) the at least two consecutive segments, so that the repeating sequence
of phases continues from one segment to the consecutive segment, wherein the order of
the phases is the same in the at least two consecutive segments and in each transition
zone of two of the at least two consecutive segments.
Embodiments of the operating method follow from the description of the system and the
appended claims.
Furthermore, a method of manufacturing a system is proposed, for transferring electric
energy to a vehicle, in particular to a track bound vehicle such as a light rail vehicle or to a
road automobile, wherein
- an electric conductor arrangement is provided for producing an alternating
electromagnetic field and for thereby transferring the energy to the vehicle,
- the conductor arrangement comprises a plurality of consecutive segments, wherein the
segments extend in the direction of travel of the vehicle, which is defined by the track or
path of travel,
- each segment is combined with an assigned controller adapted to control the operation
of the segment independently of the other segments,
- the controllers of at least two consecutive segments, which follow each other in the
direction of travel of the vehicle, or which follow each other opposite to the direction of
travel, are connected to each other and/or to a central controlling device so that the at
least two consecutive segments can operated at the same time,
- each segment comprises at least three alternating current lines for carrying phases of a
multi-phase alternating current in order to produce the alternating electromagnetic field,
- the consecutive segments are electrically connected in parallel to each other to a current
supply I
- the alternating current lines of each segment comprise a plurality of sections which
extend transversely to the direction of travel of the vehicle,
- the transversely extending sections of the at least three alternating-current lines of each
segment form, if viewed in the direction of travel, a repeating sequence of phases of the
alternating current, while the segment is operated under control of the assigned
controller, wherein each complete repetition of the sequence of phases comprises one
transversely extending section of each phase and the order of the phases is the same in
each complete repetition,
- the controllers of the at least two consecutive segments and/or the central controlling
device arelis adapted to operate the at least two consecutive segments, so that the
repeating sequence of phases continues from one segment to the consecutive segment,
wherein the order of the phases is the same in the at least two consecutive segments
and in each transition zone of two of the at least two consecutive segments.
Embodiments of the manufacturing method follow from the description of the system and the
appended claims.
The repeating sequence of phases of the alternating current allow for production of a
continuous electromagnetic field in the transition zones of consecutive segments if the
segments are operated at the same time. Preferably, the distance between any two
transversely extending sections, which follow each other in the direction of travel, is constant.
Therefore, the electromagnetic field produced is particularly homogeneous with respect to
the direction of travel.
The transversely extending sections produce the relevant parts of the electromagnetic field
for energy transfer to the vehicle. In particular, as described in WO 2010/031593 A1, they
produce a row of successive magnetic poles of an electromagnetic field, wherein the
successive magnetic poles have alternating magnetic polarities. The row of successive
magnetic poles extends in the travel direction of the vehicle. In this case, the alternating
current flows through successive sections of the same phase alternating in opposite
directions. In practice, this can be realised by alternating current lines which extend along a
meandering path in the direction of travel. In particular, the alternating current lines may be
located alternating on opposite sides of the conductor arrangement. Due to this serpentinelike
configuration of the alternating current lines, the transversely extending sections are
connected to each other by other sections which at least partly extend in the direction of
travel.
In particular, the assigned controller may control a converter which is connected to a direct
current supply line on a direct current side (i.e. the supply side) of the converter and which is
connected to the alternating current lines of the segment on an alternating current side (i.e.
the segment side) of the converter. Therefore, the converters are inverters. These inverters
and the current supply may be adapted in the way described in WO 20101031593 A1.
Alternatively, the current supply line may be an alternating current supply line. In this case,
the converters are ACIAC converters which, in particular, convert the alternating current in
the alternating current supply to an alternating current in the segments having a different
frequency. It is also possible to combine two or more current supplies, namely at least one
alternating current supply with at least one direct current supply, wherein each supply is
connected to the respective segment via either an inverter or an ACIAC converter.
In contrast to the arrangement of WO 201 01031 593 All due to the parallel arrangement of
the segments, each segment is only indirectly connected to the other segments via the
assigned converter (either an inverter or an ACIAC-converter), the supply line and the
respective assigned converter of the other segment. However, according to a specific
embodiment, the same converter may be assigned to a plurality of segments. In this case,
the individual segments which are connected to the common assigned converter are not
consecutive segments and, preferably, are not operated at the same time. For example, a
corresponding switch or set of switches is provided in an alternating current connection
between the segment side of the converter and at least one of the segments. By controlling
the switch or switches, the segment or segments islare selected which can be operated by
the converter (by feeding an alternating current to the segment) at a time.
Furthermore, it is preferred that there is a synchronization link which is connected to the
converters for synchronizing operation of the converters. The system is adapted to
synchronize the assigned converters of consecutive segments, which are operated at the
same time, in a manner so that the electromagnetic field produced by the consecutive
segments is continuous at the interface or interfaces between the consecutive segments.
With respect to the system, the following is preferred:
- for a sequence of consecutive segments, an converter is assigned and connected to
each segment, wherein the assigned converter is connected to a current supply and is
adapted to convert a current carried by the current supply to an alternating current
carried by the at least one alternating current line of the segment, so that there is a
sequence of assigned converters for the corresponding sequence of consecutive
segments,
- each of the converters of the sequence of assigned converters is connected to a
synchronization link for synchronizing operation of the sequence of assigned
converters,
- the system is adapted to synchronize the sequence of assigned converters in a manner
so that the electromagnetic field produced by the sequence of consecutive segments is
continuous at the interface or interfaces between the consecutive segments.
With respect to the operating method, the following is preferred:
- for a sequence of consecutive segments, a converter is assigned and connected to
each segment, wherein the assigned converter is connected to a current supply and
converts -during operation of the segment - a current carried by the current supply to
an alternating current carried by the at least one alternating current line of the segment,
so that there is a sequence of assigned converters for the corresponding sequence of
consecutive segments,
- each of the converters of the sequence of assigned converters is connected to a
synchronization link for synchronizing operation of the sequence of assigned
converters and receives andlor outputs -during operation of the segment and if
another converter of the sequence of assigned converters is also operated - a
synchronization signal via the synchronization link,
- the sequence of assigned converters is synchronized in a manner so that the
electromagnetic field produced by the sequence of consecutive segments is continuous
at the interface or interfaces between the consecutive segments.
With respect to the manufacturing method, the following is preferred:
- for a sequence of consecutive segments, assigning and connecting an converter to
each segment, wherein the assigned converter is connected to the current supply and
is adapted to convert a current carried by the current supply to an alternating current
carried by the at least one alternating current line of the segment, so that there is a
sequence of assigned converters for the corresponding sequence of consecutive
segments,
- connecting each of the converters of the sequence of assigned converters to a
synchronization link for synchronizing operation of the sequence of assigned
converters,
- enabling the system to synchronize the sequence of assigned converters in a manner
so that the electromagnetic field produced by the sequence of consecutive segments is
continuous at the interface or interfaces between the consecutive segments.
Due to the conductor arrangement as described above and below and due to the
synchronization of the assigned converters of consecutive segments, the electromagnetic
field does not comprise step-like changes of the field intensity at the interface, at each point
in time while the consecutive segments are operated together. In particular, the course of the
electromagnetic field in the direction of travel does not change at the interface between the
consecutive segments, due to the synchronization. The electromagnetic field, which is
produced by the at least three alternating current lines per segment may be produced as a
moving magnetic wave, i.e. the magnetic flux fluctuates in the manner of a wave (an example
will be given below), which moves in or opposite to the direction of travel of the vehicle, the
wave being continuous in the transition zone(s) of the consecutive segments. In particular,
the assigned controllers of the at least two consecutive segments are synchronized so that
the electromagnetic field produced by the at least two consecutive segments forms the
magnetic wave. Such a moving wave has the advantage that the vehicle may stop at any
location and the inductive energy transfer may continue independently of the location.
As mentioned above, the alternating current lines may follow a meandering path in the
direction of travel. Consequently, the transversely extending sections of the alternating
current lines are connected to each other by connecting sections which at least partly extend
in the direction of travel. For example, these connecting sections may comprise curved line
sections.
In order to produce a homogenous electromagnetic field having constant width in the
direction of the extension of the transversely extending sections, these transversely
extending sections should have the same lengths. As a result, the connecting sections of the
different transversely extending sections are located in the same two side margins at the
opposite (lateral) sides of the conductor arrangement. Depending on the way of arranging
the connecting sections, the space which is required for laying the connecting sections in the
side margins differs.
It is an object of the preferred embodiment, which will be described in the following, to reduce
the space in the side margins which is required for the connecting sections. In particular, the
depth of the side margins (in the vertical direction) should be as small as possible, since the
alternating current lines may weaken the construction of the track.
In order to solve this object, it is proposed to arrange the alternating current lines in a manner
so that, in the course of the meandering path of the respective alternating current line:
- the transversely extending section of a first phase of the alternating current extends
from a first side of the conductor arrangement towards a second side of the conductor
arrangement, which is the side opposite to the first side of the conductor arrangement,
- the transversely extending section of a second phase of the alternating current, which
follows the first phase in the order of phases, extends from the second side of the
conductor arrangement towards the first side of the conductor arrangement,
- the transversely extending section of a third phase of the alternating current, which
follows the second phase in the order of phases, extends from the first side of the
conductor arrangement towards the second side of the conductor arrangement,
- if there are more than three phases, the transversely extending section(s) of the next
phase or next phases in the order of phases extend(s) in the opposite direction
between the first and second side of the conductor arrangement compared to the
transversely extending section of the preceding phase in the order of phases, until the
last phase is reached.
In addition or alternatively, this object is solved by a conductor arrangement, wherein, if
viewed in the direction of travel from a first of the two consecutive segments to a second of
the two consecutive segments, a transversely extending section of the first consecutive
segment follows a transversely extending section of the second consecutive segment in the
repeating sequence of phases of the alternating current. For example, in the case of a threephase
alternating current having phases U, V, W, and if the order of the sequence of the
transversely extending sections is U - V - W - U - V - W - U - V - W . . . (as mentioned
above), the first six transversely extending sections may be part of the second segment, the
third transversely extending section carrying phase U may be part of the second segment,
the third transversely extending section carrying phase V may be part of the first segment
and all further transversely extending sections in the sequence may be part of the second
segment or of further segments. To illustrate this, a number can be added to the letter of the
phase, wherein the number designates the segment which comprises the transversely
extending section. E. g., U1 denotes a transversely extending section carrying phase U
belonging to segment 1. According to the above example, the sequence of phases can
therefore be denoted by: U1 - V1 - W1 - U1 - V1 - W1 - U2 - V1 - W2 ... In case of a
four-phase alternating current having phases U, V, W, X, an example of a sequence would
be: U1 -V1 -W1 -XI -U1 -V2-W1 -X2 ...
The transversely extending sections, which follow each other in the order of the phases and
which belong to different segments, are located in the transition zone of the two consecutive
segments. They are the first or last transversely extending sections of the respective
segment which carry a particular phase. These first or last transversely extending sections
can be used in particular for connecting the alternating current lines to a converter (see
above) or to another device which feeds the alternating current lines with the alternating
current during operation. Alternatively, these last or first transversely extending sections can
be connected to the other alternating current lines of the same segment to form an electric
star point connection. Since the first and last transversely extending sections alternating
belong to different segments it is possible to form the repeating sequence of phases at
regular distances between the transversely extending sections, wherein the first solution of
the object described above (saving space in the side margins) is realized, namely the next
transversely extending section in the order of phases extends in the opposite direction
between the first and second side of the conductor arrangement compared to the
transversely extending section of the preceding phase in the order of the phases, if the
course of the meandering alternating current lines is followed. In other words, the two
solutions of the object are equivalent, if regular, constant distances between the transversely
extending sections are realized not only within the segments, but also in the transition zone
of the two consecutive segments.
According to a preferred embodiment, each of the converters (e.g. inverters and/or ACIACconverters)
comprises a control device (in particular the assigned controller mentioned
above) which is connected to the synchronization link for receiving a synchronization signal
transferred by the synchronization link, wherein the control devices of the sequence of
assigned converters are adapted to output a synchronization signal via the synchronization
link to the consecutive converter of the sequence of assigned converters. Output and receipt
of a synchronization signal may depend on the question whether the converter, the
preceding converter andlor the successive converter is operated. For example, the output of
a synchronization signal to the consecutive converter (i.e. the successive converter) may
stop if the operation of the converter is ceased. Consequently, the successive converter may
not receive a synchronization signal anymore, but may output a synchronization signal to its
consecutive converter, so that synchronized operation of the consecutive converters is
guaranteed. In addition or alternatively, starting operation of a converter may cause starting
the output of a synchronization signal to the consecutive converter.
In particular, the control devices of the sequence of assigned converters are adapted or
operated to output the synchron~zations ignal only if the converter, which comprises the
control device, is operating, i.e. is producing the alternating current carried by the
corresponding segment of the sequence of consecutive segments.
Transferring synchronization signals from any converter to the respective consecutive
converter only has the advantage that no central synchronization control is required. On the
other hand, delays of the delivery of synchronization signals are minimized and are the same
for each pair of consecutive converters, provided that the ways of transferring the
synchronization signal and the sectional lengths of the synchronization link between the
consecutive converters are the same for all pairs of consecutive converters. In particular,
delay can be anticipated and, thereby, its effect can be eliminated.
Preferably, the synchronization signal is a continuous signal which is transferred at least
during operation of the converter or converters. For example, the synchronization signal can
be a signal which is also used internally by the converter to control the switching processes
of switches which generate the alternating current on the segment side of the converter.
Typical signals for this internal control are pulse width modulation control signals which are
transferred from a central controller of the converter to different drive units which actually
drive the electric currents that cause the switching of the switches. In this context, the term
pulse width modulation control signal is understood to be the control signal which is used to
produce the result of a pulse width modulation process. Alternatively, instead of pulse width
modulation control signals, clock signals of the central controller of the converter may be
output as synchronization signal. According to a specific embodiment, the synchronization
signal may be a binary signal having two different signal levels corresponding to "0" and "1 ",
wherein the level change from "0" to "1" or vice versa is used to synchronize the phase of the
alternating current produced by the converter and wherein the length of time between a
change from " 0 to "1" or vice versa to the next change from " 0 to "1" or from "1" to "0" is
used to synchronize the time period of periodic processes during the operation of the
converters, such as the time period of the alternating current which is produced by the
converter. Variants are possible, such as using the time period of the synchronization signal
for defining a pre-defined fraction of the time period of the alternating current produced by
the converter.
In some cases, vehicles may travel always in the same direction along the consecutive
segments of the conductor arrangement. However, in other cases, the direction of travel may
change from time to time to the opposite direction. In the latter case, it is preferred that the
system comprises a control unit which is connected to the synchronization link and which is
adapted to output a direction selection signal via the synchronization link to at least one of
the control devices of the converters and wherein the system is adapted in such a manner
that the control device(s) receiving the direction selection signal outputs the synchronization
signal via the synchronization link to the converter which is the consecutive converter in the
direction of the sequence of assigned converters which corresponds to the direction selection
signal, i.e. the synchronization signal is output either to the consecutive converter in a first
direction or to the consecutive converter in the opposite direction depending on the direction
selection signal. In other words, the order of the sequence of assigned converters can be
reversed, if necessary. In particular, the synchronization link may comprise an additional line
for transferring the direction selection signal to the converters.
The following aspect of the invention can be realized in connection with the basic idea of the
present invention, as mentioned above, but can also be realized if the operation of the at
least two consecutive segments is performed in a different manner andlor if the segments
are not parallel to each other. This aspect of the invention refers to the following: A system
for transferring electric energy to a vehicle, in particular to a track bound vehicle such as a
light rail vehicle or to a road automobile, wherein
- the system comprises an electric conductor arrangement for producing an alternating
electromagnetic field and for thereby transferring the energy to the vehicle,
- the conductor arrangement comprises a plurality of consecutive segments, wherein the
segments extend along the path of travel of the vehicle, each segment comprising at
least one alternating current line for carrying an alternating current in order to produce
the alternating electromagnetic field,
- the system comprises a current supply (e.g. a direct current supply or an alternating
current supply) for supplying electric energy to the segments,
- the segments are electrically connected in parallel to each other to the current supply,
- an converter is assigned and connected to each segment, wherein the assigned
converter is connected to the current supply and is adapted to convert a current carried
by the current supply to an alternating current carried by the at least one alternating
current line of the segment.
Optionally, a sequence of the assigned converters may be defined which corresponds to a
corresponding sequence of consecutive segments.
The underlying problem of the aspect is that at least some of the converters are not operated
continuously, since the corresponding segment should not produce an electromagnetic field
all the time. Corresponding reasons have been explained above. For example, if the
presence of a vehicle above the respective segment is detected or if it is detected that a
vehicle will occupy the space next to the segment (in particular above the segment)
according to a pre-defined criterion, the converter which is assigned to the segment should
start operation. It is an object of this aspect of the invention that the operation should be
started effectively and reliably. In particular, fluctuations of the alternating electric current,
which is produced by the converter immediately after starting the operation, should be
reduced or avoided. Fluctuation of the alternating current would cause fluctuations of the
frequency and/or of the field intensity which is produced by the segment which, in turn, would
cause transients of the voltage which is induced in the receiver of the vehicle.
It is proposed that at least one of the converters and preferably all converters comprise(s) a
starting device for starting operation of the converter.
The starting device is adapted to start the operation of the converter in two steps. In the first
step a power supply of the converter is switched on. In the second step, with a predefined
delay after the first step or when it has been detected that the power supply has become
stable, production of the alternating current carried by the corresponding segment is enabled.
Regarding the method of operating the system operation of the converter is started in two
steps, first switching on power supply and second, with a predefined delay or when it has
been detected that the power supply has become stable, enabling production of the
alternating current carried by the corresponding segment. Enabling production of the
alternating current means that the production of the alternating current is started. In other
words, the production of the alternating current is not started when the power supply of the
converter is switched on, but is started later in the second step. Consequently, since there is
time for the power supply to become stable, the alternating current can be produced in a
stable manner from start onwards.
Preferably, synchronization is also realized in connection with this aspect of the invention. In
this case, the converter receives a synchronization signal preferably when the first step of the
start operation is performed and, therefore, the synchronization signal can be used by the
converter when the power supply has been switched on to prepare synchronized operation,
before the production of the alternating current is started. For example, a central controller of
the converter, which is adapted to control the operation of switch drive units (for driving
switches of the converter) may be started in the first step or in between the first step and the
second step of the starting operation. The synchronization signal may be used to
synchronize the operation of the central controller before the operation of the switches of the
converter is started which causes the production of the alternating current. In particular, the
power supply of the switch drive units may be switched on later than the power supply of the
converter, namely in the second step and, thereby, the production of the alternating current is
started.
Examples of the present invention and further embodiments will be described with reference
to the attached drawing. The figures of the drawing show:
Fig. 1 schematically a rail vehicle which is travelling on a track that is equipped with an
electric conductor arrangement comprising a plurality of consecutive segments
which are connected in parallel to each other to a direct current supply,
Fig. 2 an example of a three-phase conductor arrangement of a single segment,
Fig. 3 a diagram showing alternating currents through the three phases of the
arrangement according to Fig. 2,
Fig. 4 a diagram showing schematically the movement of a magnetic wave produced by
the conductor arrangement along the track and showing the movement of the
receiving device due to the movement of the vehicle on the track,
Fig. 5 for three different points in time, a situation in which a rail vehicle travels on a track,
wherein the track is provided with a plurality of consecutive segments of a
conductor arrangement, wherein the segments can be switched on and off for
providing the vehicle with energy,
Fig. 6 a preferred embodiment of a three-phase conductor arrangement at the transition
zone of two consecutive segments of the conductor arrangement, wherein electric
lines of the two consecutive segments are arranged to extend from the transition
zone to a location sideways of the track,
Fig. 7 an arrangement similar to the arrangement shown in Fig: 6, wherein two star-point
connections of the three phases of the consecutive segments are located in the
transition zone,
Fig. 8 an arrangement similar to the arrangement shown in Fig. 1, wherein the alternating
current lines of in each case two consecutive segments extend from a common
transition zone to respective inverters in the manner shown in Fig. 6,
Fig. 9 an arrangement similar to the arrangement shown in Fig. 8, wherein inverters are
assigned to two segments of the conductor arrangement, wherein the segments
which are connected to the same inverter are not consecutive segments, i.e. are not
neighbouring segments in the sequence of consecutive segments,
Fig. 10 a module which is connected to the direct current supply line shown in Fig. 9 and is
also connected to the three alternating current lines of two segments, wherein the
module comprises an inverter, a constant current source and arrangement of
switches for switching on and off the three alternating current lines of the segments
so that only one of the segments is provided with electric energy from inverter at a
time,
Fig. 11 an arrangement similar to the arrangement shown in Fig. 8, wherein the
consecutive segments do not have the same lengths in the direction of travel and
wherein the track is adapted to provide energy to a bus instead of a tram, wherein
an enlarged view of one of the inverters is shown in the lower left of the figure,
Fig. 12 a circuit diagram showing schematically three consecutive segments of a conductor
arrangement, for example the conductor arrangement shown in Fig. 1, Fig. 5, Fig.8,
Fig. 10 or Fig. I 1, wherein an inverter is assigned to each segment for producing an
alternating current and wherein each inverter is connected to a synchronization link
and to a direct current supply,
Fig. 13 a block diagram schematically illustrating an embodiment of the arrangement for
starting the operation of a inverter,
Fig. 14 a circuit diagram of a specific embodiment of an inverter comprising a starting
device for starting the operation of the inverter,
Fig. 15 an embodiment of an interface between an inverter and a synchronization link,
wherein an additional direction selection signal line is provided,
Fig. 16 a top view of a shaped block, which may be used to support the lines of a segment,
and
Fig. 17 a vertical cross-section through half of the block of Fig. 16.
In the examples which are described with reference to the figures the converters are
inverters, but corresponding examples may comprise ACIAC-converters and the direct
current supply may be an alternating current supply instead.
Fig. 1 shows a rail vehicle 81 travelling on a track 83 which is provided with a conductor
arrangement for producing an electromagnetic field which induces an electric voltage in a
receiver 85 of the vehicle 81.
The conductor arrangement is constituted by a plurality of consecutive segments TI, T2, T3.
Further segments may be provided, but are not shown in Fig. 1. Each segment TI, T2, T3 is
connected to a direct current supply 108 via in each case one assigned inverter K1, K2, K3.
The direct current in the supply 108 is provided by a power source 101.
Fig. 2 shows the part of a conductor arrangement which may constitute one segment. The
figure is understood to show a schematic view, but the distances between the transversely
extending sections of the conduct arrangement may be to scale. The three lines 1, 2, 3 of the
conductor arrangement comprise these sections which extend transversely to the direction of
travel (from left to right or right to left). Only some of the transversely extending sections of
lines 1, 2, 3 are denoted by a reference numerals, namely three sections 5a, 5b and 5c of
line 3, some further sections of the line 3 by " 5 , one section 5x of line 2 and one section 5y
of line 1. In the most preferred case, the arrangement 12 shown in Fig. 2 is located
underground of the track so that Fig. 2 shows a top view onto the arrangement 12. The track
may extend from left to right, at the top and the bottom in Fig. 2, i.e. the transversely
extending line sections may be completely within the boundaries defined by the limits of the
track.
For example in the manner as shown in Fig. 8, the three lines 1, 2,3 may be connected to an
inverter K. At the time which is depicted in Fig. 2, a positive current I1 is flowing through line
3. "Positive" means, that the current flows from the inverter into the line. The three lines 1, 2,
3 are connected to each other at the other end of the arrangement at a common star point 4.
Consequently, at least one of the other currents, here the current 12 through the line 2 and
the current 13 through the line 1, are negative. Generally speaking, the star point rule applies
which means that the sum of all currents flowing to and from the star point is zero at each
point in time. The directions of the currents through lines 1, 2, 3 are indicated by arrows.
The sections of line 3 and the corresponding sections of lines 1, 2 which extend transversely
to the direction of travel preferably have the same width and are parallel to each other. In
practice, it is preferred that there is no shift in width direction between the transversely
extending sections of the three lines. Such a shift is shown in Fig. 2 for the reason that each
section or each line can be identified.
Preferably, each line follows a serpentine-like path (also called: meandering path) along the
track in the same manner, wherein the lines are shifted in the direction of travel by one third
of the distance between consecutive sections of the same line extending transversely to the
direction of travel. For example, as shown in the middle of Fig. 2, the distance between
consecutive sections 5 of line 3 is denoted by Tp. Within the region between these
consecutive sections 5, there are two other sections which extend transversely to the
direction of travel namely, section 5x of line 2 and section 5y of line 1. This pattern of
consecutive sections 5, 5x, 5y repeats at regular distances between these sections in the
direction of travel.
The corresponding direction of the current which flows through the sections is shown in the
left region of Fig. 2. For example, section 5a carries a current from a first side A of the
arrangement 12 to the opposite side B of the arrangement. Side A is one side of the
conductor arrangement or track (such as the right hand side in the direction of travel, when
viewed from a travelling vehicle) and side 6 is the opposite side (e.g. the left side of the
track), if the arrangement 12 is buried in the ground under the track, or more generally
speaking, extends in a horizontal plane.
The consecutive section 5b consequently carries an electric current at the same time which
is flowing from side 6 to side A. The next consecutive section 5c of line 3 is consequently
carrying a current from side A to side 6. All these currents have the same size, since they
are carried by the same line at the same time. In other words: the sections which extend
transversely are connected to each other by connecting sections which extend in the
direction of travel.
As a result of this serpentine like line arrangement, the magnetic fields which are produced
by sections 5a, 5b, 5c, . . . of the line 3 produce a row of successive magnetic poles of an
electromagnetic field, wherein the successive magnetic poles (the poles produced by section
5a, 5b, 5c, ...) have alternating magnetic polarities. For example, the polarity of the magnetic
pole which is produced by section 5a may correspond at a specific point in time a magnetic
dipole, for which the magnetic north pole is facing upwardly and the magnetic south pole is
facing downwardly. At the same time, the magnetic polarity of the magnetic field which is
produced by section 5b is oriented at the same time in such a manner that the corresponding
magnetic dipole is facing with its south pole upwardly and with its north pole downwardly.
The corresponding magnetic dipole of section 5c is oriented in the same manner as for
section 5a and so on. The same applies to lines 1 and 2.
However, the present invention is focussed on the case that there are at least three phases
and, correspondingly, three alternating current lines. Therefore, the above description of line
3 also applies to lines 1 and 2. In contrast, a conductor arrangement having only one phase
may be arranged as line 3 in Fig. 2, but instead of the star point 4, the end of the line 3
(which is located at the right hand side of Fig. 2) may also be connected to the inverter (not
shown in Fig. 2) by a connector line (not shown in Fig. 2) which extends along the track. A
two-phase arrangement may consist of lines 3 and 2, for example, but the distance between
the transversely extending sections of the two lines (or more generally speaking: of all lines)
is preferably constant (i.e. the distances between a transversely extending section of line 3 to
the two nearest transversely extending section of line 2 - in the direction of travel and in the
opposite direction - are equal).
In the case of the example shown in Fig. 2, but also in other cases, it is an object to avoid
transients of the electromagnetic field which is produced at the interface of consecutive
segments. Such transients may occur for different reasons. One possible reason is the
arrangement of the alternating current lines at the opposite ends of the segment. The
distance Tp between consecutive transversely extending sections 5 of the same line was
mentioned above. Since there are three alternating current lines 1,2,3 in the example of Fig.
2, the distance between consecutive transversely extending sections of any of the lines 1, 2,
3 is one third of the distance Tp. However, this does not apply to parts of the transition zones
at the opposite ends. On the left hand side in Fig. 2, where the lines 1, 2, 3 are connected to
an external device, such as an inverter, the distance between the first transversely extending
sections of lines 1, 2 is two thirds of the distance Tp. At the end of the segment on the right
hand side of Fig. 2, the distance between the last transversely extending sections of lines 2,
3 is also two thirds of the distance Tp. The reason for this increased distance is that it shall
be possible to maintain the repeating sequence of phases of the alternating current, even in
the transition zones of two consecutive segments.
In particular, a consecutive segment may be arranged on the left hand side of Fig. 2. In this
case, an alternating current line 3' of this consecutive segment comprises a transversely
extending section 5' which is placed in the middle between the first transversely extending
sections of lines 1, 2. If this line 3' is operated in phase with line 3, the repeating sequence of
phases is maintained in the transition zone. "In phase" means that the current carried by the
transversely extending section 5' has the same amount at the same point in time, but the
direction of the current through the transversely extending section 5' is opposite to the
direction of the current through the transversely extending section 5a.
Similarly, there may be a further consecutive segment in the area on the right hand side of
Fig. 2, wherein a transversely extending section (not shown in Fig. 2) of a line may be placed
in the middle between the last transversely extending sections of lines 2, 3.
As mentioned above, the view shown in Fig. 2 is a schematic view. This applies to the
connecting sections of lines 1, 2, 3 which connect the transversely extending sections 5 of
the lines 1, 2, 3. The connecting sections are shifted in lateral direction (the vertical direction
in Fig. 2), so that the meandering path of the individual lines 1, 2, 3 can be followed. In
practice, it is preferred to place the connecting sections "in line" with each other in the
opposite side margins of the conductor arrangement. In Fig. 2, these side margins extend
from left to right at the opposite sides A, 6 of the arrangement.
In the schematic view of Fig. 2, some of the connecting sections of line 1 are denoted by 7,
some of the connecting sections of line 2 are denoted by 8 and some of the connecting
sections of line 3 are denoted by 9. Since these connecting sections 7, 8, 9 are represented
by straight lines, they could be shifted in two narrow side margins having the width of a line.
However, this requires that the intersection between a transversely extending section and a
connecting section forms a sharp edge. In practice, such sharp edges are not preferred,
since it would exercise stress forces to the lines and since connecting sections of different
lines 1, 2, 3 would extend in parallel to each other. Therefore, an arrangement as
schematically indicated in Fig. 6 and Fig. 7 is preferred, wherein the connecting sections are
curved, starting at the intersections to the transversely extending sections.
The arrangement of the transversely extending sections in the transition zones of two
consecutive segments, as described above, allows for a homogeneous electromagnetic field
over the whole extension of the two consecutive segments, including the transition zone. In
addition, the arrangement shown in the transition zone on the left hand side of Fig. 2,
wherein a transversely extending section of the consecutive segment is arranged in betweeri
transversely extending sections of lines 1, 2 of the segment, saves space in the side
margins, where the connecting sections are placed. The meandering paths of the lines 1, 2,
3 can be mapped on each other by shifting the paths by two third of the distance Tp.
Therefore, parallel extending connecting sections can be avoided as far as possible. If the
lines would be arranged so that they can be mapped on each other by just one third of the
distance Tp, connecting lines of the three different alternating current lines 1, 2, 3 would
extend in parallel to each other in some regions of the arrangement. It should be noted that
the term "mapped on each other" does not refer to the end regions of the lines, i.e. the
transition zones to the consecutive segments.
The diagram shown in Fig. 3, depicts the currents through the phases 1, 2, 3 of Fig. 2 at an
arbitrary point in time. In the horizontal direction, the phase angle varies. The peak current
value of the currents may be in the range of 300 A respectively -300 A (vertical axis).
However, greater or smaller peak currents are also possible. 300 A peak current is sufficient
to provide propulsion energy to a tram for moving the tram along a track of some hundred
meters to a few kilometres, for example within the historic town centre of a city. In addition,
the tram may withdraw energy from an on-board energy storage, such as a conventional
electrochemical battery arrangement andlor a super cap arrangement. The energy storage
may be charged again fully, as soon as the tram has left the town centre and is connected to
an overhead line.
Fig. 4 shows a cut along a cutting plane which extends vertically and which extends in the
travel direction. The wires or bundles of wires of lines 1, 3, 2 which are located in sections of
the lines 1, 3, 2 which extend transversely to the direction of travel are shown in the lower
half of Fig. 4. In total, seven sections of the arrangement 12 which extend transversely to the
travel direction are shown in Fig. 4, at least partially. The first, fourth and seventh section in
segments TI, T5, T6 would not result in a significant energy transfer to the vehicle 81. If the
vehicle continues traveling from left to right in Fig. 9, segment T2 will be switched off and
segment T5 will be switched on instead.
As a result, only one of the segments of a pair of segments T which is connected to the same
inverter P will be operated at a time. Therefore, it is possible to combine the inverter with a
constant current source which is adapted to produce a desired constant current through a
single segment. In alternative arrangements, it would be possible, for example, to connect
more than two segments to the same inverter and to operate only one of these segments at
a time.
Fig. 10 shows a module comprising an inverter P which may be constructed as known to a
skilled person. For example, in case of a three-phase alternating current to be produced,
there may be bridges comprising a series connection of two semiconductor switches for each
phase. Since the construction of inverters is known, the details are not described with
reference to Fig. 10. On the alternating current side, the inverter P is connected to a constant
current source 12. This constant current source 12 consists of a network of passive
elements, namely one inductance 18a, 18b, 18c in each phase line of the alternating current
and one capacitance 20a, 20b, 20c in a connection which connects one of the phase lines
starting at a junction 21a, 21b, 21c to a common star point 11.
The constant current source may also comprise a second inductance in each phase line
which is located at the opposite side of the junction 21 as the first inductance 18. Such an
arrangement can be called a three-phase T-network. The purpose of the second inductance
is to minimize the reactive power produced by the segment which is connected to the
constant current source.
In the example shown in Fig. 10, the phase lines of the constant current source 12 are
connected to junctions 7a, 7b, 7c via a second capacitance 42a, 42b, 42c. The capacitances
42 serve to compensate the inherent inductances of the segments which can be connected
to the junctions 7. "Compensation" in this case means the reactive power produced by the
respective segment is minimized while the segment is operated. This illustrates the principle
that the compensating capacitance can be integrated in the module which also comprises the
constant current source.
In the example shown in Fig. 10, a first switching unit 13a comprising semiconductor
switches 16a, 16b, 16c, one in each phase line, is connected to the junctions 7a, 7b, 7c and
in a similar manner the semiconductor switches 16a, 16b, 16c of a second switching unit 13b
are also connected to the junctions 7. For example, the first switching unit 13a may be
connected to the alternating current supply 6a, 6c or 6e of Fig. 9 and the second switching
unit 13b may be connected to the alternating current supply 6b, 6d or 6f of Fig. 9.
If operation of the consecutive segments TI to T6 of Fig. 9 should start operation one after
the other, the operation of the assigned inverters PI to P3 will start in the (logical) sequence
PI -P2-P3-PI -P2-P3, but the switching unit 13a will be switched off after the inverter
operation has ceased for the first time during this sequence and the switching unit 13b will be
switched on. Synchronization signals can be output by the inverters to the consecutive
inverter according to this logical sequence, for example using corresponding addresses of a
digital data bus.
Fig. 11 schematically shows a vehicle 91, in particular a bus for public transport of people,
comprising a single receiver 95 for receiving the electromagnetic field produced by segments
on the primary side of the system. There are five consecutive segments TI, T2, T3, T4, T5
which differ with respect to the lengths in the direction of travel (from left to right in Fig. 11).
At the transition zone of segment TI to segment T2 as well at the transition zone of segment
T4 to segment T5, there are two inverters K1, K2; K4, K5, whereas at the transition zone of
segment T2 to segment T3 there is only the inverters K3 assigned to segment T3. An
enlarged view of inverter K3 is shown in the bottom left of the figure.
The effective alternating voltage of the alternating current produced by the inverters (of any
embodiment of this description) may be, for example, in the range of 500 - 1.500 V. The
frequency of the alternating current may be in the range of 15 - 25 kHz.
In the example shown in Fig. 12, three consecutive segments TI, T2, T3 are depicted.
However, the conductor arrangement may comprise any other number of segments which
form a sequence of consecutive segments. In particular, the number of segments in practice
may be larger, for example at least ten or twenty segments. The alternating current line or
alternating current lines of the segments TI, T2, T3 are represented by a single line per
segment, which comprises windings in order to indicate the inductivity which is required for
inductive energy transfer. The alternating current line(s) islare connected to the assigned
inverter K1, K2, K3. The inverters K are connected to the direct current supply via connection
lines CLa, CLb. The direct current supply comprises a first line 4a and a second line 4b at
different electric potentials. The first line 4a is electrically connected via the first connection
lines CLa to the inverters K and the second line 4b of the direct current supply is connected
via the second connection lines CLb to the inverters K.
Furthermore, Fig. 12 shows a synchronization link SL which may be realized by a digital data
bus, such as a data bus according to the CAN (controller area network)-bus-standard. The
synchronization link SL is connected to the respective inverter K at an interface IP of the
inverter K.
Optionally, an additional direction selection line may be provided and, in particular, may be
connected to the interface IP of each inverter K, in order to enable direction selection with
respect to the direction which defines the order of the sequence of consecutive segments T
and, correspondingly, the order of the sequence of assigned inverters K. However, the
direction selection line DS can be omitted, in particular if vehicles always travel in the same
direction on the track which is provided with the conductor arrangement.
In the following, an example of the operation of the consecutive segments will be given. For
example, a vehicle which always covers two consecutive segments while it is driving on the
track is to be provided with energy. In this one, two or temporarily three consecutive
segments may be operated at the same time. However, the description is not limited to the
operation of two or three consecutive segments. Rather, any other number of consecutive
segments may be operated at the same time.
If, for example, the direction of the order of the sequence of consecutive segments T is from
left to right in Fig. 12, i.e. the order is TI-T2-T3, an active inverter T (i.e. an inverter which is
operating and is therefore producing an alternating current in the respective corresponding
segment T) outputs a synchronization signal to the consecutive inverter K. If, for example,
inverter K1 is operating, it outputs a synchronization signal via the synchronization link SL to
the consecutive inverter K2. If inverter K2 is operating, it outputs a synchronization signal to
consecutive inverter K3. However, if inverter K is not operating, it does not output a
synchronization signal to the consecutive inverter K.
As a result, a sequence of consecutive inverters K which are operated at the same time
forms a chain, wherein each chain link (i.e. each inverter K) outputs a synchronization signal
to the consecutive chain link. Therefore, synchronized operation of the inverters K is
guaranteed. On the other hand, since the last chain link does not output a synchronization
signal, other inverters which are not part of the same sequence of consecutive inverters, can
also operated, but are not synchronized or are synchronized with another sequence of
consecutive inverters. In other words, there may be separate chains of active inverters and
the synchronization method described above guarantees that the inverters of each individual
chain of active inverters are operated synchronously.
If a direction selection line is present as shown in Fig. 12, the direction for transferring the
synchronization signal to the consecutive inverter K can be reversed on receipt of a direction
selection signal by the respective interfaces IP. For example, the receipt of a corresponding
direction selection signal via the direction selection line SL may cause the active inverter K3
to output a synchronization signal to the new consecutive inverter K2 and so on.
Fig. 13 shows a possible embodiment of an inverter, for example one of the inverters shown
in Fig. 1, Fig. 8, Fig. 10, Fig. 11 or Fig. 12. The controller or a plurality of controllers of the
inverter islare denoted by CTR. Furthermore, the inverter comprises a power unit PU for
providing the required form of electrical power to the inverter. In the specific embodiment
shown in Fig. 13, the inverter also comprises two starting devices SD1, SD2. However,
instead of two separate starting devices, the inverter may alternatively comprise a single
starting device which combines the functions of the two starting devices SD1, SD2 which will
be explained in the following.
The starting devices SD1, SD2 are connected to a signal line 131, which may be the same
signal line or same combination of signal lines which is used as synchronization link (for
example as explained in connection with Fig. 12). Alternatively, the signal line 131 may be an
internal signal line for connecting the different starting devices SD1, SD2 and may be
omitted, if there is a single starting device only. However, it is preferred that the starting
device or starting devices are connected to an external device via the signal line 131 or via
another signal line, so that the starting device(s) can be enabled or disabled by the external
device (which may be a central control unit of the system) for providing energy to vehicles.
As shown in Fig. 13, it is preferred that the starting device SD1 (or alternatively all starting
devices or the single starting device) is connected to a detection arrangement 133, 134 for
detecting the presence of a vehicle. In the embodiment shown in Fig. 13, it is schematically
indicated, that the area which is covered by the vehicle presence detection (as outlined by
dashed line 134) covers the whole area of the alternating current line(s) of the segment T
which islare connected to the inverter K. However, vehicle presence detection can be
performed in a different manner, for example by detecting that a vehicle has reached or
passes a pre-defined position on the track. If the vehicle presence detection system 133, 134
produces a signal indicating that the operation of the inverter K should be started (for
example by transferring a signal from loop 134 via signal line 133) the first starting device
SD1 (or the single starting device) switches on the power supply of the inverter K. In the
specific embodiment shown in Fig. 13, this is performed by closing a switch or by closing
switches in the connection lines CLa, CLb, so that the controller CTR is connected to the
power unit PU. This power unit PU may be omitted if, for example, voltage and current of the
direct current supply are suitable for operation of the inverter K without an additional power
unit PU. However, it is preferred to use such a power unit PU and, in particular, to use the
same direct current supply for operational power of the different units of inverter K and, at the
same time, for providing the energy to the alternating current line(s) of the corresponding
segment T. A corresponding example is shown by Fig. 14.
Starting the power supply of the controller CTR does not start full operation of the inverter K.
In other words, starting the power supply of the controller CTR does not start the generation
of the alternating current which is used to operate the corresponding segment T. Rather, this
full operation is started only after a delay or is started if it is detected that the power supply of
the controller CTR has become stable. "Stable" means that the power supply does not cause
fluctuations of the alternating current which is produced by the inverter K.
If the pre-defined delay period has elapsed, or if is detected that the power supply has
become stable, the second starting device SD2 (or the single starting device) enables full
operation of the inverter K, for example by outputting a corresponding enabling signal via
signal line 132.
Fig. 14 shows an inverter K, for example the inverter of Fig. 13. Inverter K comprises a first
controller CTR1 and a second controller arrangement CTR2 comprising three drive units
147a, 147b, 147c for controlling the switching operations for six switches SW 1 .. .SW6. These
switches SW (for example semiconductor switches, such as IGBTs) and their operation are
principally known in the art. The production of a three-phase alternating current through
alternating current lines 6 of the corresponding segment (not shown in Fig. 14) will not be
described in detail here. Series connections of in each case two of the switches SW1, SW2;
SW3, SW4; SW5, SW6 are connected at their opposite ends to the direct current lines 148a,
148b that are connected to the connection lines CLa, CLb via a protection and filter unit 145.
The power unit PU (which may be a distributed unit comprising two sub-units, as shown in
Fig. 14) is also connected to the direct current lines 148 and provides the first controller
CTR1 with power, provided that the first starting device SD1 has switched on the power
supply of the first controller CTRI. Furthermore, the power unit PU also provides the second
arrangement of controllers (i.e. the drive unit 147) with electrical power, if the second starting
device SD2 has switched on the power supply of the second controller arrangement CTR2.
For simplicity, the control connections of the starting devices SD1, SD2 are not or not
completely shown in Fig. 14.
The first controller CTRI has several connections to units denoted by 143 which are input or
output units for inputting or outputting signals tolfrom the first controller CTRI. For example,
the first controller CTRI and the units 143 are provided on a common board 141. However,
other embodiments are also possible.
The signal line 131 at the bottom of Fig. 14 is used for transferring synchronization signals
and for transferring signals tolfrom the first starting device SD1, such as a vehicle detection
presence signal. The signal line 131 may be a digital data bus optionally comprising an
additional direction selection signal line as mentioned above.
The first controller CTRI is adapted to control the operation of the drive units 147 based on
the synchronization which is effected by a synchronization signal that is received via the
synchronization link Sync2. During operation of the second controller arrangement CTR2 (i.e.
during operation of the drive units 147 and, therefore, during generation of the alternating
current carried by alternating current lines 6) the first controller CTRI outputs a
synchronization signal via synchronization link Syncl, preferably towards the consecutive
inverter only. If the inverter K does not receive a synchronization signal, the first controller
CTRI controls the operation of the drive units 147 without the presence of a synchronization
signal which is received from the exterior. However, it outputs a synchronization signal in any
case during operation of the drive units 147.
In the absence of a vehicle presence detection signal or if a vehicle absence signal, which
may be received by the first starting device SD1 via signal line 131, indicates that the
operation of the inverter K should stop, the first starting device SD1 switches off the power
supply of the controllers CTRI , CTR2.
Fig. 15 shows a signal interface. On the left hand side of Fig. 15, there are two
synchronization links Syncl , Sync2 from the interface to the inverter (not shown in Fig. 15).
These lines Syncl, Sync2 may be the lines shown at the bottom, right hand side of Fig. 14.
Each of the synchronization signal lines Syncl, Sync2 terminates at an input/output unit
1 53a1 153b which may be used alternatively for inputting or outputting the respective
synchronization signal to the inverter or from the inverter.
On the right hand side of Fig. 15, two lines 121 , 122 of a signal line (such as the signal line
131 of Fig. 13 or Fig. 14 or the signal line SL of Fig. 12) are shown. In the operating state
depicted by Fig. 15, the first line 121 is connected via first contacts of a switch 159 and via a
connection line 154b to the inputloutput unit 153a at synchronization line Sync2.
Furthermore, the second signal line 122 is connected via second contacts of the switch 159
via connection line 155a to the other inputloutput unit 153b at the other synchronization line
Syncl. Therefore, a synchronization signal which is received via the second line 122 is
transferred via synchronization line Syncl to the inverter. On the other hand, a
synchronization signal which is output by the inverter via synchronization line Sync2
transferred via the first signal line 121, in particular to the consecutive inverter, according to
the present order of the sequence of consecutive inverters.
On receipt of a corresponding direction selection signal via line DS, the switch 159 switches
to a different operating state, in which the first signal line 121 is connected via first contacts
of the switch 159 and via a connection line 155b to inputloutput unit 153b where the first
synchronization line Syncl terminates. In addition, the second signal line 122 is connected
via second contacts of the switch 159 and via a connection line 154a with the other
inputloutput unit 153a, where the second synchronization line Sync2 terminates. During
operation of the inverter, a synchronization signal which is received via the second signal line
122 is therefore transferred via the second synchronization line Sync2 to the inverter. On the
other hand, a synchronization signal which is output by the inverter is transferred via the first
synchronization line Syncl to the first signal line 121.
In particular, inputloutput units 153 can be adapted in such a manner that synchronization
signals which are output by the unit 153 are addressed to a pre-defined inverter. Therefore, a
synchronization signal which is output by unit 153a will always be transferred to a specific
inverter which is the consecutive inverter with respect to a first direction of the order of
sequence of consecutive inverters. A synchronization signal which is output by the other unit
153b will always by addressed to a second specific inverter which is the consecutive inverter
according to the opposite direction of the order of sequence of consecutive inverters. In both
cases, the first signal line 121 is used to transfer the respective synchronization signal.
Fig. 16 shows a top view of a shaped block. The block 304 comprises six recesses 31 5a -
31 5f which extend perpendicularly to a centre line 310 which divides the block 304 in two
halves. The centre line 31 0 extends in the direction of travel of a vehicle, if the block 304
forms parts of a track for the vehicle.
The recesses 31 5 are parallel to each other and are arranged within the same horizontal
plane which is parallel to the image plane of Fig. 16. The recesses 315 extend in width
direction (the vertical direction in Fig. 1) over about three quarters of the total width of block
304. They are arranged symmetrically to the centre line 31 0.
Each recess has a U-shaped cross-section to receive a cable, i.e. an electric line. The
dashed lines shown in Fig. 16 which extend along the recesses 31 5 are centre lines of the
recesses 31 5. At each of the two opposite ends of the straight recesses 31 5, there a
bifurcated curved recess region 31 6 which forms a transition to a peripheral straight recess
317 extending along the lateral edge of the block 304. Cables can be laid in a manner
consecutively extending from the straight recesses 31 5 through the curved recess region 31 6
into the peripheral straight recess 31 7, thereby changing the direction of extension from
transversely to the direction of travel (for transversely extending sections of the line) to
parallel to the direction of travel.
The curved recess regions 31 6 allow for placing a cable, which extends through the recess
315 in such a manner that it continues to either the left or the right, if viewed in the straight
direction of the recess 31 5. For example, a cable (not shown in Fig. 16) may extend through
recess 31 5b, may turn to the right - while extending through recess region 31 6 -and may
then extend through the straight recess 317 which extends perpendicularly to the recesses
31 5 on the opposite side of curved recess region 31 6. There are two peripheral straight
recess regions 317 on opposite sides of block 304. The cable may then turn to the right
through the recess region 31 6 at the end of recess 315e and may then extend through
recess 31 5e. At the end of recess 31 5e, which is shown in the lower part of Fig. 16, the cable
may again turn left through recess region 316 into the other straight recess 317. The other
recesses 31 5 may be used for two other cables.
As shown in Fig. 17, the depth of the recesses 31 5, 31 6, 31 7 is different. The depth of recess
31 5 is sufficient to receive one cable. The depth of the curved recess region 31 6 increases
from the end of recess 31 5 to recess 31 7 as indicated by a dashed line in Fig. 2. The bottom
profile of the curved recess region 316 is not fully shown in Fig. 2, since the sectional view
includes a region 31 9 of block 304 which is not recessed. Each of the curved recess regions
31 6 comprises such an island region 31 9 which is located between the two curved branches
of the curved recess region 31 6. One of the branches extends above the plane of Fig. 17 and
the other branch extends below the plane of Fig. 17. In addition, the island region 319 is
located between the straight recess 31 7 and the two branches of the curved recess region
31 6.
Since the depth of the curved recess region 316 increases towards the straight recess 31 7,
different cables can be laid upon one another. The depth of the straight recess 31 7 is
sufficient to arrange two cables upon one another extending in the same straight direction.
For example, a first cable may extend trough the lower recess 317 in Fig. 16 and may turn
left into recess 315b through the recess region 316 shown in the bottom left part of Fig. 16. In
addition, a second cable may extend trough recess 31 5a, may turn into the recess 31 7,
thereby crossing (if viewed from above) the first cable.
The example concerning the extension of cables or electric lines given above refers to one
specific application for laying three meandering cables. However, the use of the shaped
block 304 shown in Fig. 16 and 17 is not restricted to this application. Rather, for example,
less or more than three cables can be laid using the block 304 shown in Fig. 16 and 17.
We claim:
1. A system for transferring electric energy to a vehicle, in particular to a track bound
vehicle such as a light rail vehicle (81) or to a road automobile, wherein
- the system comprises an electric conductor arrangement for producing an
alternating electromagnetic field and for thereby transferring the energy to the
vehicle,
the conductor arrangement comprises a plurality of consecutive segments (TI, T2,
T3, T4, T5), wherein the segments (TI, T2, T3, T4, T5) extend in the direction of
travel of the vehicle, which is defined by the track or path of travel,
each segment (TI, T2, T3, T4, T5) is combined with an assigned controller (CTRI)
adapted to control the operation of the segment (TI, T2, T3, T4, T5) independently
of the other segments (TI, T2, T3, T4, T5),
the controllers (CTRI) of at least two consecutive segments (TI, T2, T3, T4, T5),
which follow each other in the direction of travel of the vehicle, or which follow each
other opposite to the direction of travel, are connected to each other and/or to a
central controlling device so that the at least two consecutive segments (TI, T2, T3,
T4, T5) can operated at the same time,
each segment (TI, T2, T3, T4, T5) comprises at least three alternating current lines
(1,2,3) for carrying phases of a multi-phase alternating current in order to produce
the alternating electromagnetic field,
the consecutive segments (TI, T2, T3, T4, T5) are electrically connected in parallel
to each other to a current supply,
the alternating current lines (1, 2, 3) of each segment (TI, T2, T3, T4, T5) comprise
a plurality of sections (5) which extend transversely to the direction of travel of the
vehicle,
the transversely extending sections (5) of the at least three alternating current lines
(1, 2, 3) of each segment (TI, T2, T3, T4, T5) form, if viewed in the direction of
travel, a repeating sequence of phases of the alternating current, while the segment
(TI, T2, T3, T4, T5) is operated under control of the assigned controller (CTRI),
wherein each complete repetition of the sequence of phases comprises one
transversely extending section (5) of each phase and the order of the phases is the
same in each complete repetition,
the controllers (CTRI) of the at least two consecutive segments (TI, T2, T3, T4, T5)
andlor the central controlling device arelis adapted to operate the at least two
consecutive segments (TI, T2, T3, T4, T5), so that the repeating sequence of
phases continues from one segment (T2) to the consecutive segment (T3), wherein
the order of the phases is the same in the at least two consecutive segments (TI,
T2, T3, T4, T5) and in each transition zone of two of the at least two consecutive
segments (TI, T2, T3, T4, T5).
The system of claim 1, wherein the system is adapted to synchronize the assigned
controllers (CTR1) of the at least two consecutive segments (TI, T2, T3, T4, T5) in a
manner so that the electromagnetic field produced by the at least two consecutive
segments (Ti, T2, T3, T4, T5) forms a magnetic wave which moves in or opposite to the
direction of travel of the vehicle, the wave being continuous in the transition zone of the
consecutive segments (TI, T2, T3, T4, T5).
The system of claim 1 or 2, wherein, if viewed in the direction of travel from a first (T2) of
the two consecutive segments (TI, T2, T3, T4, T5) to a second (T3) of the two
consecutive segments (TI, T2, T3, T4, T5), a transversely extending section (5') of the
first consecutive segment (T2) follows a transversely extending section (5) of the second
consecutive segment (T3) in the repeating sequence of phases of the alternating current.
The system of one of claims 1 to 3, wherein the transversely extending sections (5) ot
each of the alternating current lines (1, 2, 3) are connected to each other via connecting
sections (7, 8, 9), which at least partly extend in the direction of travel, so that each of
the alternating current lines (1, 2, 3) follows a meandering path in the direction of travel
in which the connecting sections (7, 8, 9) are located alternating on opposite sides of the
conductor arrangement, and wherein the transversely extending sections (5) of a
complete repetition of the phases of the repeating sequence are formed by the
meandering paths of the alternating current lines (1, 2, 3) in the following manner:
- the transversely extending section (5) of a first phase (3) of the alternating current
extends from a first side (6) of the conductor arrangement towards a second side
(A) of the conductor arrangement, which is the side opposite to the first side of the
conductor arrangement,
- the transversely extending section (5x) of a second phase (2) of the alternating
current, which follows the first phase (3) in the order of phases, extends from the
second side (A) of the conductor arrangement towards the first side (B) of the
conductor arrangement,
- the transversely extending section (5y) of a third phase (1) of the alternating current,
which follows the second phase (2) in the order of phases, extends from the first
side (6) of the conductor arrangement towards the second side (A) of the conductor
arrangement,
- if there are more than three phases, the transversely extending section(s) of the
next phase or next phases in the order of phases extend(s) in the opposite direction
between the first and second side of the conductor arrangement compared to the
transversely extending section of the preceding phase, until the last phase is
reached.
5. A method of operating a system for transferring electric energy to a vehicle, in particular
to a track bound vehicle such as a light rail vehicle (81) or to a road automobile, wherein
- an electric conductor arrangement is operated for producing an alternating
electromagnetic field and for thereby transferring the energy to the vehicle,
- a plurality of consecutive segments (TI, T2, T3, T4, T5) of the conductor
arrangement is operated, wherein the segments (TI, T2, T3, T4, T5) extend in the
direction of travel of the vehicle, which is defined by the track or path of travel,
- for each segment (TI, T2, T3, T4, T5), an assigned controller (CTR1) is operated to
control the operation of the segment (TI, T2, T3, T4, T5) independently of the other
segments (TI, T2, T3, T4, T5),
- the controllers (CTR1) of at least two consecutive segments (TI, T2, T3, T4, T5),
which follow each other in the direction of travel of the vehicle, or which follow each
other opposite to the direction of travel, are operated in connection with each other
andlor with a central controlling device so that the at least two consecutive
segments (TI, T2, T3, T4, T5) are operated at the same time,
- in each segment (TI, T2, T3, T4, T5), at least three alternating current lines (1, 2, 3)
carry phases of a multi-phase alternating current in order to produce the alternating
electromagnetic field,
- the consecutive segments (TI, T2, T3, T4, T5) are electrically connected in parallel
to each other to a current supply,
- the alternating current lines (1, 2, 3) of each segment (TI, T2, T3, T4, T5) comprise
a plurality of sections which extend transversely to the direction of travel of the
vehicle,
- the transversely extending sections (5) of the at least three alternating-current lines
of each segment (TI, T2, T3, T4, T5) form, if viewed in the direction of travel, a
repeating sequence of phases of the alternating current, while the segment (TI, T2,
T3, T4, T5) is operated under control of the assigned controller (CTRI), wherein
each complete repetition of the sequence of phases comprises one transversely
extending section of each phase and the order of the phases is the same in each
complete repetition,
- the controllers (CTR1) of the at least two consecutive segments (TI, T2, T3, T4, T5)
andlor the central controlling device operate(s) the at least two consecutive
segments (TI, T2, T3, T4, T5), so that the repeating sequence of phases continues
from one segment (T2) to the consecutive segment (T3), wherein the order of the
phases is the same in the at least two consecutive segments (TI, T2, T3, T4, T5)
and in each transition zone of two of the at least two consecutive segments (TI, T2,
T3, T4, T5).
6. The method of claim 5, wherein the assigned controllers (CTR1) of the at least two
consecutive segments (TI, T2, T3, T4, T5) are synchronized so that the electromagnetic
field produced by the at least two consecutive segments (TI, T2, T3, T4, T5) forms a
magnetic wave which moves in or opposite to the direction of travel of the vehicle, the
wave being continuous in the transition zone of the consecutive segments (TI, T2, T3,
T4, T5).
7. The method of claim 5 or 6, wherein, if viewed in the direction of travel from a first (T2) of
the two consecutive segments (TI, T2, T3, T4, T5) to a second (T3) of the two
consecutive segments (TI, T2, T3, T4, T5), a transversely extending section of the first
consecutive segment (T2) follows a transversely extending section of the second
consecutive segment (T3) in the repeating sequence of phases of the alternating current.
8. The system of one of claims 5 to 7, wherein the transversely extending sections (5) of
each of the alternating current lines (1, 2, 3) are connected to each other via connecting
sections (7, 8, 9), which at least partly extend in the direction of travel, so that each of
the alternating current lines (1, 2, 3) follows a meandering path in the direction of travel
in which the connecting sections (7, 8, 9) are located alternating on opposite sides of the
conductor arrangement, and wherein the transversely extending sections (5) of a
complete repetition of the phases of the repeating sequence are formed by the
meandering paths of the alternating current lines (1, 2, 3) in the following manner:
- the transversely extending section (5) of a first phase (3) of the alternating current
extends from a first side (B) of the conductor arrangement towards a second side
(A) of the conductor arrangement, which is the side opposite to the first side of the
conductor arrangement,
- the transversely extending section (5x) of a second phase (2) of the alternating
current, which follows the first phase (3) in the order of phases, extends from the
second side (A) of the conductor arrangement towards the first side (B) of the
conductor arrangement,
the transversely extending section (5y) of a third phase (1) of the alternating current,
which follows the second phase (2) in the order of phases, extends from the first
side (B) of the conductor arrangement towards the second side (A) of the conductor
arrangement,
if there are more than three phases, the transversely extending section(s) of the
next phase or next phases in the order of phases extend(s) in the opposite direction
between the first and second side of the conductor arrangement compared to the
transversely extending section of the preceding phase, until the last phase is
reached.
9. A method of manufacturing a system for transferring electric energy to a vehicle, in
particular to a track bound vehicle such as a light rail vehicle (81) or to a road
automobile, wherein
- an electric conductor arrangement is provided for producing an alternating
electromagnetic field and for thereby transferring the energy to the vehicle,
- the conductor arrangement comprises a plurality of consecutive segments (TI, T2,
T3, T4, T5), wherein the segments (TI, T2, T3, T4, T5) extend in the direction of
travel of the vehicle, which is defined by the track or path of travel,
- each segment (TI, T2, T3, T4, T5) is combined with an assigned controller (CTRI)
adapted to control the operation of the segment (TI, T2, T3, T4, T5) independently
of the other segments (TI, T2, T3, T4, T5),
- the controllers (CTRI) of at least two consecutive segments (TI, T2, T3, T4, T5),
which follow each other in the direction of travel of the vehicle, or which follow each
other opposite to the direction of travel, are connected to each other and/or to a
central controlling device so that the at least two consecutive segments (TI, T2, T3,
T4, T5) can operated at the same time,
- each segment (TI, T2, T3, T4, T5) comprises at least three alternating current lines
(1, 2, 3) for carrying phases of a multi-phase alternating current in order to produce
the alternating electromagnetic field,
- the consecutive segments (TI, T2, T3, T4, T5) are electrically connected in parallel
to each other to a current supply,
- the alternating current lines (1, 2, 3) of each segment (TI, T2, T3, T4, T5) comprise
a plurality of sections which extend transversely to the direction of travel of the
vehicle,
- the transversely extending sections (5) of the at least three alternating-current lines
of each segment (TI, T2, T3, T4, T5) form, if viewed in the direction of travel, a
repeating sequence of phases of the alternating current, while the segment (TI, T2,
T3, T4, T5) is operated under control of the assigned controller (CTRl), wherein
each complete repetition of the sequence of phases comprises one transversely
extending section of each phase and the order of the phases is the same in each
complete repetition,
- the controllers (CTR1) of the at least two consecutive segments (TI, T2, T3, T4, T5)
andlor the central controlling device arelis adapted to operate the at least two
consecutive segments (TI, T2, T3, T4, T5), so that the repeating sequence of
phases continues from one segment (T2) to the consecutive segment (T3), wherein
the order of the phases is the same in the at least two consecutive segments (TI,
T2, T3, T4, T5) and in each transition zone of two of the at least two consecutive
segment (TI, T2, T3, T4, T5)s.
10. The method of claim 9, wherein the system is adapted to synchronize the assigned
controllers (CTR1) of the at least two consecutive segments (TI, T2, T3, T4, T5) so that
the electromagnetic field produced by the at least two consecutive segments (TI, T2, T3,
T4, T5) forms a magnetic wave which moves in or opposite to the direction of travel of
the vehicle, the wave being continuous in the transition zone of the consecutive
segments (TI , T2, T3, T4, T5).
11. The method of claim 9 or 10, wherein the alternating current lines (1, 2, 3) of the at least
two consecutive segments (TI, T2, T3, T4, T5) are laid so that, if viewed in the direction
of travel from a first of the two consecutive segments (TI, T2, T3, T4, T5) to a second of
the two consecutive segments (TI, T2, T3, T4, T5), a transversely extending section of
the first consecutive segment (T2) follows a transversely extending section of the second
consecutive segment (T3) in the repeating sequence of phases of the alternating current.
12. The system of one of claims 9 to 1 1, wherein the transversely extending sections (5) of
each of the alternating current lines (1, 2, 3) are connected to each other via connecting
sections (7, 8, 9), which at least partly extend in the direction of travel, so that each of
the alternating current lines (1, 2, 3) follows a meandering path in the direction of travel
in which the connecting sections (7, 8, 9) are located alternating on opposite sides of the
conductor arrangement, and wherein the transversely extending sections (5) of a
complete repetition of the phases of the repeating sequence are formed by the
meandering paths of the alternating current lines (1, 2, 3) in the following manner:
- the transversely extending section (5) of a first phase (3) of the alternating current
extends from a first side (6) of the conductor arrangement towards a second side
(A) of the conductor arrangement, which is the side opposite to the first side of the
conductor arrangement,
- the transversely extending section (5x) of a second phase (2) of the alternating
current, which follows the first phase (3) in the order of phases, extends from the
second side (A) of the conductor arrangement towards the first side (B) of the
conductor arrangement,
- the transversely extending section (5y) of a third phase (1) of the alternating current,
which follows the second phase (2) in the order of phases, extends from the first
side (B) of the conductor arrangement towards the second side (A) of the conductor
arrangement,
- if there are more than three phases, the transversely extending section(s) of the
next phase or next phases in the order of phases extend(s) in the opposite direction
between the first and second side of the conductor arrangement compared to the
transversely extending section of the preceding phase, until the last phase is
reached.