Arrangement for supplying devices of a locomotive with
electric energy and method for operating said
arrangement
The invention relates to an arrangement for supplying
electrical energy to devices of a locomotive. In
addition, the invention relates to a locomotive with
such an arrangement and to a method for operating such
an arrangement.
The invention relates to both locomotives with an
assembly for providing traction energy from an
electrical supply system and locomotives with an
internal combustion engine for generating electrical
energy for the traction.
A locomotive is understood to mean any type of rail-
mounted vehicles with a dedicated traction apparatus
(i.e. with at least one traction motor). The term
includes in particular independent vehicles which can
be coupled to a rail-mounted vehicle trainset, but also
railcars or multiple-unit trains, in which both devices
for generating the traction and space for cargo and/or
passengers are provided in the same vehicle or vehicle
area. In particular, the combination of devices
required in total for the generation of the traction
(for example high-voltage assembly or internal
combustion engine, current converters, traction
intermediate circuit and traction motors) can be
arranged distributed in different units of a trainset
or units of another rail-mounted vehicle. The invention
is suitable to a particular degree for rail-mounted
vehicle units which have at least the current converter,
the traction intermediate circuit and at least some of
the traction motors and which can be decoupled from
other rail-mounted vehicle units.
Apart from the devices which are required directly for
the traction (for example high-voltage assembly,
traction inverter and traction motors), locomotives
have additional devices which enable an operation of
the locomotive. These auxiliary devices or auxiliary
units likewise require electrical energy and, in
specific cases, are connected to a traction
intermediate circuit via an auxiliary unit inverter,
with the energy required for the traction also being
drawn from the traction intermediate circuit. Examples
are fans for the traction motors, radiators for the
current converters, compressors for compressing gases
(for example for producing compressed air for a braking
system), a fire extinguisher for the locomotive,
electronic devices for controlling the operation of the
locomotive, battery chargers, heaters, for example
window heater, air-conditioning devices, socket outlets,
lighting devices. A further group of electrical devices
which are arranged in rail-mounted vehicle units which,
under certain circumstances, are coupled to the
locomotive can be connected to the traction
intermediate circuit via a dedicated, additional
inverter.
It arises in particular outside of the normal running
operating mode of a locomotive that the locomotive
cannot be operated with energy from the energy source
used during the normal running operating mode. Examples
of such situations are a missing overhead line in the
case of an electric locomotive, a ban on the operation
of the internal combustion engine of the locomotive
(for example in enclosed halls without an extractor)
and/or for the maintenance or repair of the locomotive.
For example, however, it may arise in a vehicle depot
when the locomotive is first brought into commission or
is undergoing maintenance, that the locomotive
nevertheless needs to be moved. It is advantageous here
if the locomotive moves in self-propelled fashion.
An object of the present invention is to specify a
method and an arrangement of the type mentioned at the
outset which enable an operating mode of the locomotive
in particular in the abovementioned situations, wherein
the energy source used for the normal operating mode of
the locomotive (for example diesel engine or electrical
supply system) is not available. Any additional
complexity in the form of special supply devices should
be kept to an absolute minimum in this case.
In accordance, with a basic concept of the present
invention, at least one auxiliary unit inverter is used
for such an extraordinary operating mode of the
arrangement, said auxiliary unit inverter supplying
electrical energy from a traction intermediate circuit
of the locomotive to auxiliary units of the locomotive
during the normal operating mode. However, in the
extraordinary operating mode, the direction of the
energy flow is reversed, i.e. the electrical energy is
supplied via the AC voltage side of the auxiliary unit
inverter, rectified by the inverter and fed into the DC
voltage intermediate circuit.
Only one AC voltage terminal of the arrangement or the
locomotive is required for feeding the electrical
energy, said AC voltage terminal being capable of being
connected to an AC voltage power supply system (for
example a stationary low-voltage power supply system
with a rated voltage of 400 V, for example). For
example, low-voltage power supply systems are generally
available in all maintenance halls and depots. The sole
requirement is a cable which is long enough for the
locomotive to be able to move with the electrical
energy from the power supply system, but in self-
propelled fashion with the aid of a traction motor.
Preferably, a line (sometimes also referred to as
current path below) is used for supplying the energy to
the auxiliary unit inverter, with a transformer being
located in said line. During the normal operating mode
of the locomotive, the transformer is used for
operating the auxiliary units on an AC voltage which is
reduced in comparison with the output voltage of the
auxiliary unit inverter on the AC voltage side thereof.
In the case of the reverse direction of energy flow in
the extraordinary operating mode of the locomotive, the
transformer can now be used for stepping up a
relatively low AC voltage and for making available the
voltage which has been stepped up to the auxiliary unit
inverter on the AC voltage side thereof. Therefore, a
relatively high voltage can be achieved in the DC
voltage intermediate circuit by virtue of the
transformer, with the result that traction of the
locomotive is more effective and is possible at a
higher power.
In particular a single-phase AC voltage power supply
system or else a DC voltage power supply system is a
possible energy source for the normal operating mode of
the locomotive. Alternatively, the energy source can be
a diesel engine, for example, which drives a generator
which generates an AC voltage. The actual energy source
is then the diesel engine. However, the generator will
sometimes be considered to be the energy source since,
for the purposes of the present invention, it is only
the electrical part of the energy supply which is
relevant.
In particular, the invention proposes a method for
operating an arrangement for supplying electrical
energy to devices of a locomotive, wherein, during a
normal operating mode of the arrangement:
electrical energy from a DC voltage intermediate
circuit is converted via at least one traction
inverter in order to supply electrical energy to
at least one traction motor of the locomotive,
electrical energy from the DC voltage intermediate
circuit is supplied to auxiliary units of the
locomotive via an auxiliary unit inverter,
wherein, during an extraordinary operating mode of the
arrangement:
electrical energy from an AC voltage power supply
system is supplied to a transformer of the
arrangement via an AC voltage terminal,
the electrical energy is stepped up to a higher
voltage level by the transformer,
the energy which has been stepped up is fed into
the DC voltage intermediate circuit via the
auxiliary unit inverter, and
electrical energy from the DC voltage intermediate
circuit is supplied to at least one traction motor
of the locomotive via the traction inverter.
Correspondingly, the arrangement for supplying
electrical energy to devices of the locomotive can have
the following:
a DC voltage intermediate circuit, which has a
terminal for connection to an energy source,
at least one traction inverter for generating an
AC voltage from a DC voltage in a DC voltage
intermediate circuit, wherein the traction
inverter is connected with a DC voltage side to
the DC voltage intermediate circuit and is or can
be connected with an AC voltage side to a traction
motor of the locomotive,
an auxiliary unit inverter for generating an AC
voltage from the DC voltage in the DC voltage
intermediate circuit, wherein the auxiliary unit
inverter is connected with a DC voltage side to
the DC voltage intermediate circuit and is or can
be connected with an AC voltage side, via a
transformer, to auxiliary units of the locomotive,
wherein a primary side of the transformer is
connected to the AC voltage side of the auxiliary
unit inverter, and a secondary side of the
transformer is or can be connected to the
auxiliary units,
an AC voltage terminal, which is connected to the
secondary side of the transformer.
One development of the invention is based on the
problem of it being possible for very high currents to
flow for a short period of time in the event of the
external AC voltage power supply system suddenly being
connected for supplying the intermediate circuit via
the auxiliary unit inverter, which currents may result
in fuse devices responding. In particular,
unintentional interruption of the currents may then
arise. The invention therefore proposes charging the DC
voltage intermediate circuit with a precharging device
prior to supplying power to a traction motor of the
locomotive. Since intermediate circuits are generally
equipped with high capacitances in order to smooth
fluctuations in the DC voltage, the charging operation
can take some time.
Various charging concepts are conceivable, which can
also sometimes be combined with one another. Thus, the
charging of the DC voltage intermediate circuit can be
brought to an end automatically, for example once a
predetermined time span has elapsed since the beginning
of charging. If the capacitances and inductances
involved in the charging operation are known, such a
time span can be calculated in advance. However, it is
also possible to carry out the charging operation once
in order to measure the charging time required for
reaching a desired voltage in the intermediate circuit.
In accordance with another concept, the charging of the
DC voltage intermediate circuit is brought to an end if
it is established that a predetermined DC voltage has
been reached in the DC voltage intermediate circuit.
Since control of the current converter connected to the
intermediate circuit generally comprises a
corresponding measuring device, arrangements which are
known and available at present do not need to be
modified.
Preferably, the electrical energy for charging the DC
voltage intermediate circuit is drawn from the same AC
voltage power supply system via the AC voltage terminal,
said AC voltage power supply system also being used
later as energy source during the actual extraordinary
operating mode. In this case, however, the current
flowing during charging is limited to a lower value in
comparison with a current flowing into the DC voltage
intermediate circuit later during operation of the
traction motor via the AC voltage terminal. This lower
value does not need to be constant during the charging
operation. Instead, the limitation can also consist
merely in that an electrical resistor or a plurality of
electrical resistors are connected into the current
path. Instead of resistors or in addition, it is also
conceivable to also connect a high inductance. It is of
course also possible for other current-limiting devices
to be used, for example an electronically controlled
limiting device.
In order to connect the current-limiting means, a
switching device can be used which is built permanently
into the arrangement, for example. Thus, for example,
the current path used for the normal or else for the
extraordinary operating mode can be interrupted by the
switching device and is located in a bypass which can
be connected and which bridges the interrupted section
of the current path, the current-limiting device.
A further problem on which one configuration of the
invention is based relates to filter devices, which are
generally provided for damping and/or filtering
undesired oscillation frequencies on the AC voltage
side of the auxiliary unit inverter. These filter
devices are designed for the normal operating mode of
the locomotive. During the extraordinary operating mode,
however, the conditions are different. In particular,
the AC voltage which is applied to the AC voltage
terminal during the extraordinary operating mode has a
different frequency, for example 50 Hz. On the other
hand, oscillation excitation which arises during the
normal operating mode does not take place.
The invention therefore proposes disconnecting the
filter devices or at least some of said filter devices
and/or modifying the filter devices or the filter
device automatically for the extraordinary operating
mode. For example, in the case of a three-phase AC
voltage supply to the auxiliary units, the filter
device can be implemented by virtue of a star circuit
comprising three capacitances. In this case, for
example, the star circuit is isolated from the three-
phase line automatically by means of being disconnected.
Exemplary embodiments of the invention will now be
described with reference to the attached drawing, in
the individual figures of which:
figure 1shows a DC voltage intermediate circuit with
auxiliary units connected thereto and an AC
voltage terminal for the extraordinary
operating mode, and
figure 2shows' an arrangement comprising three auxiliary
unit inverters and auxiliary units connected
thereto, which can be used for the
extraordinary operating mode.
Figure 1 shows a diesel engine 1, which drives a
generator 3. The generator 3 generates a three-phase
alternating current, which is rectified via a rectifier
5. The rectifier 5 is connected to a DC voltage
intermediate circuit 7. The potentials of the DC
voltage intermediate circuit 7 are denoted by P-UD+
(upper side, in figure 1, of the intermediate
circuit 7) and by P-UD- (lower side, in figure 1, of
the intermediate circuit 7). The potential P-UD- can be
connected to vehicle ground by the point denoted by the
reference symbol 19.
A traction inverter 9, which supplies four drive motors
17 of the rail-mounted vehicle via a three-phase
connection, a braking chopper 11, to which a braking
resistor 12 is connected, an auxiliary unit inverter 13
which supplies power to auxiliary units 18 via a three-
phase AC line, and a consumer inverter 15, which
supplies electrical energy to the consumers, for
example in a coupled trainset via a single-phase train
busbar, are connected to the intermediate circuit 7.
The auxiliary unit inverter 13 illustrated in figure 1
is connected to the auxiliary units 18 via an isolating
transformer 14, which brings about DC isolation. In
addition, the three-phase line which connects the
secondary side (low-voltage side) of the transformer 14
to the auxiliary units 18, is provided with an AC
voltage terminal 21, which can be connected to an AC
voltage power supply system for the extraordinary
operating mode. For example, the AC voltage terminal 21
may be a three-phase rated socket for a 400 V low-
voltage power supply system.
In comparison with the arrangement illustrated in
figure 1, a large number of modifications can be
performed. For example, instead of the diesel engine
and the generator and the three-phase rectifier 5, a
connection to a single-phase high-voltage power supply
system can be provided. In addition to the DC voltage
intermediate circuit 7, one or more further
intermediate circuits can be provided, via which some
of the traction motors or additional traction motors
are supplied with energy.
Further devices can be connected to the DC voltage
intermediate circuit and/or integrated therein, in
particular fuses and/or a series resonant circuit.
A plurality of auxiliary unit inverters can be
connected to the same DC voltage intermediate circuit,
as is envisaged in the case of figure 2.
The supply to the auxiliary units can merely be
configured to be single-phase. Correspondingly, the AC
voltage terminal would also be designed to be single-
phase for the extraordinary operating mode.
Further modifications are possible.
In the extraordinary operating mode, as has been
mentioned, the AC voltage terminal 21 is connected to
an AC voltage power supply system, with the result that
electrical energy is drawn from the power supply system
and can be fed into the DC voltage intermediate circuit
7 once it has been stepped up by the transformer 14. In
this case, preferably, as will be described in yet more
detail with reference to figure 2, first the DC voltage
intermediate circuit 7 is charged before one or more
traction motors are fed via the traction inverter(s) 9.
In particular, it is expedient to supply electrical
energy to only some of the traction motors in the
extraordinary operating mode. This is sufficient for
moving the locomotive at least slowly and over short
distances. Higher speeds and greater distances are
generally not desired in the extraordinary operating
mode.
The auxiliary units 18 may be in particular one or more
of the auxiliary units mentioned at the outset in this
description. For example, the auxiliary units 18 also
include a cooling device for cooling the current
converter 13, the transformer 14 and/or for cooling one
or more of the other current converters 9, 11, 15
and/or the traction motor 17. The control devices for
controlling the operation of the current converters 9,
11, 13, 15 can also belong to the auxiliary units 18.
In the extraordinary operating mode, however, operation
of the current converter 15 for supplying coupled rail-
mounted vehicle units can be dispensed with.
Figure 2 shows three auxiliary unit current converters
31a, 31b, 31c, which can be connected to the same DC
voltage intermediate circuit. However, it is also
possible for two or all of the current converters 31 to
be connected to different intermediate circuits. As an
alternative or in addition, the intermediate circuits
can be connected to one another or are connected for
the extraordinary operating mode. As a result, in the
extraordinary operating mode, energy is fed into the
first intermediate circuit via an auxiliary unit
inverter, energy is transmitted into the second
intermediate circuit, and a traction motor can be
operated with energy from the second intermediate
circuit.
The current converters 31 are used, during the normal
operating mode of the locomotive, to supply power to
auxiliary units, which are symbolized by a box with the
reference symbol 38 in figure 2. In this case, power is
supplied to the auxiliary units 38 via a connection and
distribution device 36. The current converter 31c shown
in figure 2 may be, for example, the auxiliary unit
inverter 13 shown in figure 1.
The current converters 31 are each connected to the
device 36 via a transformer 33a, 33b, 33c, to be
precise in the exemplary embodiment illustrated here in
each case via a three-phase line 35a, 35b, 35c.
The following statements apply merely to the current
converter 31c. In alternative configurations, the
embodiments can also relate to one or both of the other
current converters 31a, 31b, however.
The auxiliary unit inverter 31c is connected to a
filter device for filtering out disruptive frequencies
during the normal operating mode via the transformer
33c associated with said inverter. The filter device is
noted by the reference symbol 39 and contains, as is
illustrated symbolically in figure 2, one or more
capacitances, for example. In addition, a switch is
illustrated in the filter device 39. By actuating the
switch the filter device 39 can be disconnected, i.e.
it is no longer effective in the disconnected state.
For example, the switch of the filter device 39 is a
transistor switch, which can be driven by a central
controller of the entire arrangement shown in figure 1
and figure 2. The control units for controlling the
operation of the various inverters or rectifiers 5, 9,
11, 13, 15 can also belong to the central controller.
In particular, and this applies not only in relation to
the exemplary embodiments shown in figure 1 and
figure 2, the method of the present invention can be
implemented by a computer, which implements the
operations required for the introduction and further
implementation of the extraordinary operating mode,
with the exception of a connection, which can be
produced manually, for example, between the AC voltage
terminal and the AC voltage power supply system. In
particular, the computer can control all of the
switching operations and/or the operation of the
auxiliary unit converter(s) which are required in the
extraordinary.operating mode. All of the switches in
figure 2 can therefore preferably be controlled by the
computer.
In addition, a switch 43 (in the case of a three-phase
line a three-phase switch, for example a contactor) ,
with which a section of the line 35c can be interrupted,
is also located in the line 35c between the transformer
33c and the device 36.
In addition, the section of the line 35c with the
switch 43 is bridged by a bypass 45, with a switch 47
and a limiting device 49 likewise being connected in
series in the bypass 45. In the case of a three-phase
line 35c, such a bypass is generally provided for each
of the phases. However, the implementation is also
possible with only one bypass in each of the two phases.
As is illustrated at the bottom right in figure 2, the
line 35c ends at an AC voltage terminal 41. For the
extraordinary operating mode, it is therefore possible
to connect the AC voltage terminal 41 to an AC voltage
power supply system or else to an AC voltage generator.
In preparation for the actual extraordinary operating
mode, first the switch 43 is opened, the filter device
39 is disconnected, then the switch 47 is closed, a
current which is fed into the AC voltage terminal 41
from the outside is routed via the bypass 45 and the
resistor 49, this current is stepped up to a higher
voltage level by the transformer 33c and is fed into
the auxiliary unit inverter 31c on the AC voltage side
thereof which faces the transformer 33c. As a result,
the auxiliary unit inverter 31c, in contrast to its
other normal operating mode, generates a direct current
which is fed into the corresponding intermediate
circuit. As a result, the intermediate circuit is
charged. Once the charging has come to an end, the
switch 47 is opened, the switch 43 is closed and
therefore current is supplied from the AC voltage
terminal 41, via the transformer 33c, to the auxiliary
unit inverter 31c on the AC voltage side thereof via
the normal current path of the line 35c. The current
which is generated in this case and during the actual
extraordinary operating mode on the DC voltage side of
the inverter 31c can be used for supplying electrical
energy from the intermediate circuit to at least one
traction motor.
During the extraordinary operating mode, auxiliary
units 38 are preferably supplied with energy via the AC
voltage terminal 41 and the device 36 directly, without
needing to take the bypass via the intermediate circuit.
Such a bypass supply via the intermediate circuit is
also conceivable, however, in particular when
individual auxiliary units are connected merely to
another auxiliary unit inverter (for example 31a, 31b).
The operation of such auxiliary units during the
extraordinary operating mode, for example cooling
devices, ensures the full functioning of the auxiliary
unit inverter 31c and the other current converters
shown in figure 1, for example.
We Claim:
1. A method for operating an arrangement for
supplying electrical energy to devices of a locomotive,
wherein, during a normal operating mode of the
arrangement:
- electrical energy from a DC voltage intermediate
circuit (7) is converted via at least one traction
inverter (9) in order to supply electrical energy
to at least one traction motor (17) of the
locomotive,
- electrical energy from the DC voltage intermediate
circuit (7) is supplied to auxiliary units (18) of
the locomotive via an auxiliary unit inverter (13),
wherein, during an extraordinary operating mode of the
arrangement:
- electrical energy from an AC voltage power supply
system is supplied to a transformer (14) of the
arrangement via an AC voltage terminal (21),
- the electrical energy is stepped up to a higher
voltage level by the transformer (14),
- the energy which has been stepped up is fed into
the DC voltage intermediate circuit (7) via the
auxiliary unit inverter (13), and
- electrical energy from the DC voltage intermediate
circuit (7) is supplied to at least one traction
motor (17) of the locomotive via the traction
inverter (9).
2. The method as claimed in the preceding claim,
wherein the DC voltage intermediate circuit (7) is
charged prior to power being supplied to the traction
motor (17) in the extraordinary operating mode.
3. The method as claimed in the preceding claim,
wherein the charging of the DC voltage intermediate
circuit (7) is brought to an end once a predetermined
time span has elapsed.
4. The method as claimed in claim 2, wherein the
charging of the DC voltage intermediate circuit (7) is
brought to an end if it is established that a
predetermined DC voltage has been reached in the DC
voltage intermediate circuit (7).
5. The method as claimed in one of claims 2 to 4,
wherein the electrical energy for charging the DC
voltage intermediate circuit (7) is drawn from an AC
voltage power supply system via the AC voltage terminal
(21) , and wherein the current flowing during charging
is limited to a lower value in comparison with a
current flowing later during operation of the traction
motor (17) via the AC voltage terminal (21) into the DC
voltage intermediate circuit (7).
6. The method as claimed in the preceding claim,
wherein limiting means (49) for limiting the current to
the lower value for charging are added to the circuit
and are shut down when the charging operation is
brought to an end.
7. The method as claimed in one of the preceding
claims, wherein the AC voltage terminal (21) for the
extraordinary operating mode is connected to a low-
voltage power supply system, in particular a three-
phase AC voltage power supply system.
8. The method as claimed in one of the preceding
claims, wherein a filter device (39) for damping and/or
filtering undesirable oscillation frequencies is
arranged between the AC voltage side of the auxiliary
unit inverter (31) and the AC voltage terminal (41) and
is shut down during the extraordinary operating mode.
9. An arrangement for supplying electrical energy to
devices of a locomotive, wherein the arrangement has:
- a DC voltage intermediate circuit (7), which has a
terminal for connection to an energy source (3),
- at least one traction inverter (9) for generating
an AC voltage from a DC voltage in the DC voltage
intermediate circuit (7), wherein the traction
inverter (9) is connected with a DC voltage side
to the DC voltage intermediate circuit (7) and is
or can be connected with an AC voltage side to a
traction motor (17) of the locomotive,
- an auxiliary unit inverter (13) for generating an
AC voltage from the DC voltage in the DC voltage
intermediate circuit (7), wherein the auxiliary
unit inverter (13) is connected with a DC voltage
side to the DC voltage intermediate circuit (7)
and is or can be connected with an AC voltage side,
via a transformer (14), to auxiliary units (18) of
the locomotive, wherein a primary side of the
transformer (14) is connected to the AC voltage
side of the auxiliary unit inverter (13), and a
secondary side of the transformer (14) is or can
be connected to the auxiliary units (18),
- an AC voltage terminal, which is connected to the
secondary side of the transformer (14).
10. The arrangement as claimed in the preceding claim,
wherein the arrangement also has a charging device (43,
45, 47, 49) for charging the DC voltage intermediate
circuit, wherein the charging device is connected to
the AC voltage terminal (41) and is configured so as to
charge the DC voltage intermediate circuit via the
transformer (33c).
11. The arrangement as claimed in the preceding claim,
wherein the charging device (43, 45, 47, 4 9) has
current-limiting means (49) for limiting an electrical
current flowing during the charging.
12. The arrangement as claimed in the preceding claim,
wherein the charging device (43, 45, 47, 49) has a
switching device (43, 47), with which a current path
(35c), which connects the AC voltage terminal (41) to
the DC voltage intermediate circuit, can be switched
over in such a way that the current path (35c) is
routed via the limiting means (49).
13. The arrangement as claimed in one of the preceding
claims, wherein the AC voltage terminal (41) is
configured so as to be connected to a low-voltage power
supply system, in particular a three-phase AC voltage
power supply system.
14. The arrangement as claimed in one of the preceding
claims, wherein the arrangement has a filter device
(39) for damping and/or filtering undesirable
oscillation frequencies between the AC voltage side of
the auxiliary unit inverter (31c) and the AC voltage
terminal, and wherein the arrangement has a shutdown
device for shutting down the filter device (39) while
the DC voltage intermediate circuit is fed electrical
energy via the AC voltage terminal (41).
15. A locomotive with an arrangement as claimed in one
of the preceding claims.

The invention relates to the operation of an arrangement for supplying devices of a locomotive with electric energy.
During normal operation of the arrangement, electric energy is converted from a DC voltage intermediate circuit (7) by at least one
traction converter (9) in order to supply at least one drive engine (17) of the locomotive with electric energy. Furthermore, auxiliary
systems (18) of the locomotive are supplied by an auxiliary converter (13) with electric energy from the DC voltage intermediate
circuit (7). During extraordinary operation of the arrangement, electric energy from an AC voltage net is supplied to a transformer
(14) of the arrangement by a AC voltage connection (21), the electric energy is transformed by the transformer (14) to a higher
voltage level, the energy that was up-transformed is fed by the auxiliary converter into the DC voltage intermediate circuit (7) and
at least one drive engine (17) of the locomotive is supplied with electric energy from the DC voltage intermediate circuit (7) by the
traction converter (9).