Operation of rail vehicles to limit power peaks in an electrical supply

Abstract

A rail vehicle is configured for extracting electrical energy from a power supply external to the vehicle and has at least one electrical energy storage unit. In a first operating mode, the rail vehicle travels by means of energy extracted from the power supply and without energy from the energy storage unit. In a second operating mode, the rail vehicle travels, at least in part, by means of energy from the energy storage unit and/or at reduced traction power in comparison to the first operating mode. The rail vehicle includes a controller set up for activating the first or the second operating mode, as a function of an upper consumption limit, which defines the permissible upper limit of the power that can be extracted from the power supply. The upper consumption limit is established in a variable manner so as to prevent power peaks in the power supply.

Claims

1. A rail vehicle configured for extracting electrical energy from a power supply external to the rail vehicle, comprising: at least one electrical energy storage unit, wherein the rail vehicle is configured to travel in a first operating mode using energy extracted from the power supply and without energy from the at least one energy storage unit, and, in a second operating mode using, at least in part, energy from the at least one energy storage unit and/or at a reduced traction power in comparison to the first operating mode, wherein the rail vehicle comprises a controller configured for activating the first operating mode or the second operating mode as a function of an upper consumption limit which defines a permissible upper limit of power that is extractable from the power supply when energy consumption from the power supply is possible, and wherein the upper consumption limit is variably established in order to prevent power peaks in the power supply.

2. The rail vehicle according to claim 1, wherein the controller is furthermore configured for activating the first or the second operating mode as a function of a power demand variable of the rail vehicle.

3. The rail vehicle according to claim 2, wherein the second operating mode is activated, at the latest, when the power demand variable is greater than the upper consumption limit.

4. The rail vehicle according to claim 1, wherein the upper consumption limit is established based on at least one of the following: a target set by a driver; a target set by a controller external to the vehicle; and a target set by a controller internal to the vehicle.

5. The rail vehicle according to claim 1, wherein the upper consumption limit is determined based on a measurement variable that relates to a property of the power supply external to the vehicle.

6. The rail vehicle according to claim 5, wherein the measurement variable is a voltage variable of the power supply or a phase shift variable of the power supply, and wherein the second operating mode is activated if the voltage variable or the phase shift variable fulfills an activation criterion.

7. The rail vehicle according to claim 1, wherein the second operating mode is activated if the momentary power of the power supply is greater than a permissible threshold value.

8. A method for operation of a rail vehicle configured for extracting electrical energy from a power supply external to the rail vehicle and having at least one electrical energy storage unit, the method comprising: activating a first operating mode or a second operating mode as a function of an upper consumption limit which defines a permissible upper limit of power that is extractable from the power supply when energy consumption from the power supply is possible, wherein the upper consumption limit is established in variable manner so as to prevent power peaks in the power supply; wherein, in the first operating mode, the rail vehicle is configured to travel by means of energy extracted from the power supply external to the vehicle, and without energy from the energy storage unit, and, in the second operating mode, the rail vehicle is configured to travel at least in part by means of energy from the energy storage unit and/or at reduced traction power in comparison to the first operating mode.

9. An arrangement comprising: at least two rail vehicles configured for extracting electrical energy from a power supply external to the vehicle for travel movement, wherein a fleet controller is set up for establishing an upper consumption limit which defines a permissible upper limit of power that is extractable by at least one of the rail vehicles from the power supply when energy consumption from the power supply is possible in accordance with power demand variables that are received by each one of the rail vehicles, and in order to prevent power peaks in the power supply.

10. The arrangement according to claim 9, wherein at least one of the rail vehicles is configured according to claim 1.

11. A method for operation of a rail vehicle fleet having a first rail vehicle and at least one further rail vehicle, which are each configured for extracting electrical energy from a power supply external to the vehicle for travel movement, the method comprising: transmitting a power demand variable of each of the rail vehicles to a fleet controller; and establishing an upper consumption limit for power that is extractable from the power supply for at least one of the rail vehicles when energy consumption from the power supply is possible, in accordance with the power demand variables received, in order to prevent power peaks in the power supply.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) In the following, embodiments of the invention will be explained using the attached schematic figures. In this regard, characteristics that agree with one another in terms of their type and/or function can be provided with the same reference symbols throughout the figures.

(2) FIG. 1 shows a schematic view of a rail traffic route with a rail vehicle according to a first exemplary embodiment of the invention;

(3) FIG. 2 shows a diagram for explaining undesirable power peaks in a power supply, as they can occur, for example, during operation of the rail vehicle from FIG. 1;

(4) FIG. 3 shows a schematic representation of a drive system of the rail vehicle from FIG. 1;

(5) FIG. 4 shows a flow chart of a method according to a first exemplary embodiment, as it can be carried out using the rail vehicle from FIG. 1;

(6) FIG. 5 shows a schematic view of an arrangement according to a further exemplary embodiment of the invention, in which a rail vehicle fleet is provided.

DETAILED DESCRIPTION OF THE INVENTION

(7) In FIG. 1, a segment of a rail traffic route 1 including electrical infrastructure is shown, within which a rail vehicle 10 according to a first exemplary embodiment of the invention is operated. The rail vehicle 10 is, as an example, a multi-part train having two power cars, between which other cars can also be optionally arranged.

(8) As a usual component of the infrastructure, a public power network 2 can be seen, for example in the form of a railway power network. An overhead line 3, from which the rail vehicle 10 can extract electrical energy by means of a pantograph 12, is situated along the rail traffic route 1. Between the overhead line 3 and the public power network 2, there is a transformer station in the form of what is called a substation 4. Along the entire rail traffic route 1, of which only a segment is shown in FIG. 1, multiple such substations 4 can be provided, for example at least one substation 4 every 10 km or every 20 km.

(9) Multiple substations 4 can also be provided for a single route segment, for example if this is a route segment having a high energy demand and/or power demand. This can be the case, for example, at train stations having a potential plurality of rail vehicles 10 entering the station at the same time or in the case of route segments having a great incline.

(10) In the present case, the overhead line 3, preferably including the substation 4, forms a power supply 14 external to the vehicle. Fundamentally, however, the public power network 2 can also be comprised in the power supply external to the vehicle, according to the invention.

(11) By means of the power supply 14, electrical power for travel movement of rail vehicles 10 is made available. In this regard, the power or amount of power made available is primarily a function of the power demanded or extracted by the rail vehicles 10. If the rail vehicle 10 or a plurality of rail vehicles 10, which are supplied by the power supply 14 at the same time, demand(s) a high (cumulative) power, undesirable power peaks can occur within the power supply 14. These can put a burden on the substation 4, in particular, i.e., can express themselves in an undesirable power increase of the substation 4 and can be measured there accordingly. In general, power made available by a substation 4 can be generated as a function of consumed or demanded power or, in other words, can lag behind this demanded power.

(12) In FIG. 2, a corresponding power curve is shown as an example. To state it more precisely, the power of a substation 4 provided there, which is determined by the power P demanded by the rail vehicle(s) 10, is plotted above the time t. In this regard, a broken line indicates a permissible power peak limit L, which is not supposed to be exceeded. It can be seen that the power peak limit L is temporarily exceeded during the time periods t1 and t2. In this regard, the time periods t1, t2 can comprise only a few minutes or only a few seconds, for example less than 30 seconds.

(13) The power curve from FIG. 2 can also indicate the power extracted by a rail vehicle 10 or a fleet of rail vehicles 10. The area under the power curve corresponds to the energy extracted from the power supply 14. When the rail vehicle 10 (or the fleet) starts up from a stop or on an incline, for example, the power peak limit L can be exceeded, even if the power supply 14 is fundamentally designed to cover the energy demand of the rail vehicle 10 (or the fleet).

(14) As explained initially, the occurrence of such power peaks is connected with multiple disadvantages and can, in particular, result in increased energy costs for an operator of the rail vehicle 10 or a fleet of rail vehicles 10.

(15) According to the invention, the rail vehicle 10 therefore comprises an electrical energy storage unit 13. This unit can be supplied with electrical energy, for example, from the overhead line 3, for example when the rail vehicle 10 is standing or if not all of the energy being taken from the overhead line is needed for travel movement. Charging with electrical energy obtained within the scope of regenerative brake operation is also possible.

(16) The rail vehicle 10 also comprises a controller 17, for example a control device having at least a micro-controller, which processes algorithms and/or program instructions, so as to make desired functions available.

(17) In the present case, the controller 17 is set up for switching between a first and a second operating mode of the rail vehicle 10 and, in particular, of its drive system 100. It is also possible to provide a control device external to the vehicle, in addition or alternatively, which can be, in particular, a component of a train control system. This device can take on all of the functions of the vehicle controller 17 as described herein or, alternatively, can control this controller 17 for carrying out the functions described herein. This optional controller external to the vehicle can be a controller independent of the fleet controller 50 explained below, since it is not necessarily set up for controlling a plurality of rail vehicles 10 in a large-area territory, for example.

(18) In the following, making reference to FIG. 3, a possible embodiment of such a drive system 100 will be explained as an example. The components of this drive system 100 can fundamentally be distributed over any desired individual vehicles or power cars of the rail vehicle 10, but can optionally also be combined in one of the power cars. As shown with a broken line, numerous ones of the components of the drive system 100 can be connected with the controller 17, so as to transmit signals to it and/or receive control signals from it.

(19) The drive system 100 is electrically connected with the pantograph 12, which is also shown. Proceeding from the pantograph 12, the consumed electrical energy is passed to a conventional main transformer 142 by way of a conventional high-voltage transformer 140 and a conventional main switch 138. The main switch 138 is set up, in known manner, for cutting the electrical connection between the pantograph 12 and the main transformer 142 by means of selectively opening the switch. The high-voltage transformer 140 can measure an applied voltage and/or a current flow (and thereby also consumed power), which is applied to the main transformer 142 on the primary side.

(20) In this regard, in the present case the high-voltage transformer 140 also serves as an energy consumption measurement device, which measures the energy and/or power extracted by the rail vehicle 10 from the power supply 14.

(21) The internal structure of the main transformer 142 is also shown in greatly simplified manner. A magnetic core 148 and a primary coil 144 are shown, to which a primary voltage is applied. Furthermore, secondary coils 146 are shown, to which a (transformed) secondary voltage is applied. In the assignment of the terms primary and secondary, the point of departure is a main operating state of the main transformer 142, in which electrical energy extracted by way of the pantograph 12 is made available on the primary side and converted to a secondary voltage for further use within the rail vehicle 10.

(22) Furthermore, a power converter is connected with each of the secondary coils 146, wherein merely as an example, a first power converter 150 and a further power converter 152 are provided. The two power converters 150, 152, which can also be referred to as line current converters, can preferably be operated optionally as rectifiers or as inverters, and are connected with a direct-voltage intermediate circuit 151. Traction motors 156 are also connected with this direct-voltage intermediate circuit 151, which motors can preferably be operated optionally as motors or as generators.

(23) A motor converter 154 is switched between the direct-voltage intermediate circuit 151 and the traction motors 156, in each instance, which converter again can preferably be operated optionally as a rectifier (for generator operation) or as an inverter (for motor operation).

(24) The electrical energy storage unit 13 is also connected with the direct-voltage intermediate circuit 151; in the case shown, this unit is a battery. A charging device of the energy storage unit 13 is not shown separately; using this device it is possible to control energy consumption or energy output of this energy storage unit 13. The operation of the charging device can be controlled by the controller 17, as is indicated by a corresponding signal connection.

(25) For travel movement along the rail traffic route 1, the rail vehicle 10 is set up, in a first operating mode, for decisively and preferably exclusively extracting electrical energy from the overhead line 3, and not falling back on electrical energy from the energy storage unit 13. In this case, the line current converters 150, 152 are operated as rectifiers and the motor converter 154 is operated as an inverter, with control and/or activation by means of the controller 17. In contrast, the main transformer 142 is typically a passive component that is not controlled separately.

(26) In a second operating mode, in contrast, no exclusive energy consumption from the overhead line 3 takes place. Instead, the rail vehicle 10 is then operated, at least in part or also completely, on the basis of electrical energy from the energy storage unit 13. In addition or alternatively, the traction power that can be generated (and thereby the energy demand and, in particular, the power demand) of the rail vehicle 10 can be throttled.

(27) If the electrical energy storage unit 13 is merely supposed to be added in the second operating mode, and if energy is to be continuously extracted from the overhead line 3, the controller 17 can turn on the energy storage unit 13 or its charging device for energy output at the desired level. If instead travel movement is supposed to take place exclusively by means of energy from the energy storage unit 13, the controller 17 can analogously turn on the energy storage unit or its charging device, but at the same time also deactivate the line current converters 150, 152 or, in other words, block them. In this state, no energy from the overhead line 3 can be fed into the direct-voltage intermediate circuit 151 any longer. In order to decide whether the first or the second operating mode is supposed to be activated, the controller 17 monitors whether momentary, demanded, or future energy consumption and preferably power consumption exceeds an upper consumption limit, which defines the permissible upper limit of the power consumption from the power supply 14. In the present case, the controller 17 is set up for also defining or establishing this upper consumption limit by itself. Fundamentally, all of the variants explained above are possible variants for such a determination. In particular, a corresponding target can be set by a driver or by a controller external to the vehicle.

(28) In the case shown, it is additionally or alternatively provided to measure the voltage of the overhead line 3 that is applied to the pantograph 12 with regard to amplitude, so as to establish the upper consumption limit. This takes place by means of the high-voltage transformer 140, the measurement signals of which are transmitted to the controller 17 by way of the connection indicated with a broken line.

(29) If the amplitude of the voltage in the overhead line 3 drops below a predetermined threshold value, this indicates a great load on the power supply 14, for example because a plurality of other rail vehicles 10 is already also being supplied with energy from it. In this case, the controller 17, in order to avoid undesirable power peaks, can set the upper consumption limit (of its own rail vehicle 10) to a value that lies below the maximum possible power consumption by the rail vehicle, i.e., a value that no longer allows unlimited power consumption from the power supply. For example, the upper consumption limit can be set to a value of less than 100%, i.e., the power consumption is then restricted to a certain percentage.

(30) Subsequently, the controller 17 monitors whether the upper limit is exceeded by the power being demanded, for example, and, to state it more precisely, by a power demand variable determined on this basis. If this is the case, a switch to the second operating mode takes place. It is also possible to continue to check whether criteria for switching back to the first operating mode are present. These can be met, for example, if the upper limit is no longer reached, if the charge level of the energy storage unit 13 drops in an unacceptable manner and/or if the controller 17 issues a corresponding command to switch back.

(31) If, in contrast, the voltage measured in the overhead line 3 does not reach the predetermined threshold value, the upper consumption limit can be set to a value that equates the upper limit with the maximum possible power consumption, i.e., does not restrict the maximum possible power consumption. For example, the upper consumption limit can be set to 100% or also be eliminated entirely, so that no restriction is present, in each instance.

(32) FIG. 4 presents a flow chart of the procedure fundamentally explained above, or of a method according to an exemplary embodiment of the invention is shown, by means of which the rail vehicle 10 can be operated.

(33) In a step S1, the rail vehicle 10 is moved along the rail traffic route 1. The first operating mode is activated, i.e., the power consumption from the power supply 14 is not restricted, for example because the upper consumption limit takes on a value of 100%. Furthermore, the voltage of the overhead line 3 is measured and transmitted to the controller 17.

(34) The power consumed by the rail vehicle 10 is determined as a power demand variable, using the measurement signals detected by the high-voltage transformer 140, and continuously monitored. Alternatively or in addition (for example to form an average), the power demand variable can also be estimated or calculated using a traction force demand that is present.

(35) In steps S2 and S3, a permissible upper consumption limit is determined so as to prevent power peaks. To state it more precisely, in a step S2, which can be carried out in parallel with the step S1 and/or fundamentally continuously, the measured voltage of the overhead line 3 is compared to a predetermined threshold value. If this threshold value is exceeded, an undesirable burdened state of the power supply 14 is recognized, at which power peaks can occur. A switch to step S3 then takes place. If this threshold value is not exceeded, such a switch to step S3 does not take place, but rather further monitoring of the overhead line voltage takes place, for example.

(36) In step S3, the upper consumption limit is changed since the threshold value was exceeded in step S2. To state it more precisely, this limit is set to a value different from 100% and, stated more precisely, reduced to a lower value, so that the power consumption from the overhead line 3 is restricted. Alternative or additional possibilities for establishing the upper consumption limit, as compared to steps S2 and S3, were explained above.

(37) In a step S4, which can be carried out in parallel at least to step S3 and/or fundamentally continuously, the power demand variable (for example the demanded power) of the rail vehicle 10 is compared to the upper consumption limit. If the power demand variable lies above the upper consumption limit, a switch to a step S5 takes place and the second operating mode is activated. If this is not the case, such a switch to step S5 does not take place, but rather continued comparison of power demand and upper consumption limit takes place.

(38) In step S5, the drive system 100 from FIG. 3 is then operated in such a manner, in the way described above, that energy demand for travel movement is covered at least in part by the energy storage unit 13.

(39) In FIG. 5 an arrangement 80 according to a second exemplary embodiment is shown. The representation essentially corresponds to that of FIG. 1, and therefore reference is also made to the above explanations regarding FIG. 1 and, in particular, to the characteristics having the same reference symbols, which also apply to FIG. 5.

(40) However, the arrangement 80 does differ from that of FIG. 1, in that a rail vehicle fleet 11 having merely two rail vehicles 10, used as examples, is provided. Likewise, in contrast to FIG. 1, a fleet controller 50 is provided. The fleet controller 50, which is implemented as a Cloud Server, for example, or can be stored on such a server in the form of a computer program, communicates with communications devices 15 of the rail vehicle 10 in wireless manner and preferably by means of mobile communications. In this way, the fleet controller 50 is also indirectly connected with the controllers 17 of the rail vehicles 10. For example, signals sent by the fleet controller 50 to the corresponding communications devices 15 can be passed on to a corresponding controller 17, for example so that these controllers control a related rail vehicle 10 in a manner predetermined by the fleet controller 50.

(41) The rail vehicles 10 are configured analogous to the one from FIG. 1 or FIG. 3, with the exception of the additional communications device 15. Fundamentally, however, it can be provided in the case of this embodiment, as well, that the rail vehicles 10 do not comprise an electrical energy storage unit 13, but otherwise are configured analogous to the variants of FIG. 1 and FIG. 3. Analogous to the variants explained in connection with FIG. 3 as well as in general above, a power demand variable can be determined for each of the rail vehicles 10. In the present case, this variable is transmitted by each of the rail vehicles 10, preferably in real time, to the fleet controller 50. From this, the latter determines a cumulative energy demand or power demand of the entire rail vehicle fleet 11, which must be covered by the power supply 14.

(42) If the power demand exceeds a predetermined threshold value (for example a permissible (fleet) upper consumption limit), the power consumption from the overhead line 13 by at least one of the rail vehicles 10 is restricted. For this purpose, the fleet controller 50 sends a suitable signal, in particular an upper consumption limit, having a value different from 100%, for example, to this rail vehicle 10. Preferably, an individual upper consumption limit is transmitted to each rail vehicle 10, if its power consumption is supposed to be restricted.