Procedure for operating a vehicle

Abstract

The invention relates, among other things, to a method for operating a vehicle (10) connected to a trackside power supply network (30). According to the invention, during braking operation within a track section where energy feedback to the power supply network (30) is not permitted, a drive (70) of the vehicle (10) is operated as an electrodynamic brake, and the electrical braking energy of the drive (70) is fed to a DC link (60) of the vehicle. Energy is drawn from the DC link (60) to supply a load current (Iload) to a load on the vehicle side (90, 300, 310), and energy feedback from the DC link (60) to the power supply network (30) is blocked.

Description

[0001] The invention relates to a method for operating a vehicle that is connected to a trackside power supply network.

[0002] In railway engineering, a method is known in which, during braking in a section of track where energy recuperation into the trackside power supply network is permitted, the vehicle's drive system operates as an electrodynamic brake, and the drive's electrical braking energy is fed into a DC link. From this DC link, the braking energy is then transferred to the trackside power supply network. During operation in a section of track where energy recuperation into the trackside power supply network is prohibited, the electrodynamic braking operation is deactivated. This prevents the injection of braking energy into the DC link and, consequently, also prevents energy recuperation into the power supply network, as there is no recuperable braking energy or braking power available.

[0003] Document US 5,331,261 A discloses a regenerative braking protection system for an electrically powered vehicle, in particular a rail vehicle, wherein the vehicle is connected to a energized third rail via current collectors and regenerative braking is prevented when passing through a gap between two adjacent rail sections, unless the next section of the third rail is energized. Also known are documents JP 2008 263741 A, JP 2017 099172 A, EP 1 985 490 A1, and the article OGASA MASAMICHI: "Onboard storage in Japanese electrified lines", POWER ELECTRONICS AND MOTION CONTROL CONFERENCE (EPE / PEMC), 2010 14TH INTERNATIONAL, IEEE, PISCATAWAY, NJ, USA, September 6, 2010 (2010-09-06), pages S7-9 to S7-15.

[0004] The invention is based on the objective of further developing a method for operating a vehicle with a view to improved braking operation.

[0005] This problem is solved according to the invention by a method with the features according to claim 1. Advantageous embodiments of the method according to the invention are specified in the dependent claims.

[0006] According to the invention, it is provided that during braking operation within a section of the route with impermissible energy feedback into the power supply network, a drive of the vehicle is operated as an electrodynamic brake and electrical braking energy of the drive is fed into a DC intermediate circuit of the vehicle, energy is extracted from the DC intermediate circuit by feeding a load current into a vehicle-side load, and energy feedback from the DC intermediate circuit into the power supply network is blocked.

[0007] An advantage of the method according to the invention is that it also provides for electrodynamic braking in sections of the route where energy recuperation is prohibited, as can be the case, for example, with so-called island grids. Electrodynamic braking remains possible with the method according to the invention because energy transfer from the DC link to the power supply network is specifically blocked. The resulting electrical braking energy is directed from the DC link to a vehicle-side load, which absorbs the braking energy, for example, by converting it into heat or storing it.

[0008] A further advantage of the method according to the invention is that the wear of friction brakes is reduced because their use can be completely or at least partially dispensed with, even in sections of track without the possibility of energy recuperation.

[0009] To avoid a change in the DC link voltage or to keep the DC link voltage constant, the braking current of the drive can be measured and the load current through the load can be regulated accordingly so that the power consumed by the load corresponds to the braking power.

[0010] According to the invention, the level of the load current is adjusted depending on a braking force specification, which indicates a braking force specified for and to be exerted by the drive, i.e., the target braking force. The target braking force can, for example, be specified or set by a rail vehicle operator by adjusting a brake lever. In such a case, the braking force specification can, for example, correspond to the respective position of the brake lever.

[0011] According to the invention, the electrical braking power of the drive is calculated depending on the braking force specification, and a target load current is calculated on the basis of the calculated braking power, which is to flow through the load.

[0012] According to the invention, an internal converter, which is connected between the DC link and the vehicle-side load, is controlled depending on the calculated target load current.

[0013] The calculation of the target load current is preferably carried out in such a way that the power drawn from the DC link, which is caused by the target load current, corresponds to the braking power that is fed into the DC link by the drive according to the braking force specification during electrodynamic braking operation.

[0014] The target load current is preferably calculated as follows: Isoll t = Fsoll ⋅ V t / Ulast where Fsoll is the braking force that the drive is supposed to generate according to the braking force specification, t is the time, V is the speed of the vehicle, Ulast is the voltage at the load and Isoll is the nominal load current that the internal inverter is supposed to feed into the load.

[0015] According to the invention, the internal converter is controlled in such a way that the level of the load current corresponds to the calculated target load current.

[0016] However, inaccuracies in calculating the target load current can sometimes lead to fluctuations in the DC link voltage because the braking power fed into the DC link deviates from the power actually consumed by the load. For this reason, the invention provides that the internal converter is operated such that the load current corresponds to the calculated target load current as long as the DC link voltage remains below a predetermined maximum voltage value, and the load current is set higher than the calculated target load current when the DC link voltage exceeds the predetermined maximum voltage value. Increasing the load current easily counteracts the voltage increase. It is advantageous to determine a differential voltage value that quantitatively indicates when the maximum voltage value has been exceeded.

[0017] If such a differential voltage value exists or the maximum voltage value is exceeded, the load current is preferably increased by a current difference that is proportional to the determined differential voltage value.

[0018] The current difference can be advantageously determined using a PI controller.

[0019] With a view to preventing energy regeneration in track sections where no energy may be fed back in, it is considered advantageous if the vehicle has a grid-side converter that connects, or at least can connect, the DC link to the trackside power supply network. Energy regeneration from the DC link into the power supply network is preferably blocked by blocking the grid-side converter in the regeneration direction, for example by appropriately switching internal switching elements of the converter on and off.

[0020] In the event that the load current is too high or the power fed into the load is greater than the braking power, it is considered advantageous if the grid-side converter is controlled in such a way that it feeds grid-side energy into the DC link even during braking operation, provided that the DC link voltage falls below a predetermined minimum voltage value.

[0021] The grid-side energy or grid current that the grid-side converter feeds into the DC link during braking operation is preferably proportional to the difference between the minimum voltage value and the level of the DC link voltage, i.e., in other words, proportional to the voltage amount by which the DC link voltage falls below the minimum voltage value.

[0022] The maximum voltage value is preferably between 50 V and 150 V greater than the minimum voltage value.

[0023] As mentioned, energy feedback can be avoided by controlling the grid-side inverter. Alternatively or additionally, energy feedback can be blocked by an additional blocking device connected between the DC link and the grid-side inverter. A permanent blockage of energy feedback can advantageously be achieved by a diode whose conduction direction is oriented towards the DC link, thus allowing current and energy to flow exclusively in that direction.

[0024] In track sections where energy recuperation is permitted, energy recuperation towards the trackside power supply network is preferably allowed when the vehicle brakes, for example, when no more braking energy can or should be consumed or stored in the vehicle. Energy recuperation towards the trackside power supply network is preferably achieved by controlling the network-side inverter and / or deactivating (e.g., short-circuiting) the aforementioned blocking device.

[0025] The internal converter is preferably a DC / DC converter. A DC / DC converter makes it easy and advantageous to, for example, supply a battery with a charging current (as the load current) as a load.

[0026] If the braking energy is not to be stored, but only converted into heat, an inverter can be used as an internal converter, which applies a load current to an ohmic resistance as a load.

[0027] The invention also relates to a vehicle with a pantograph that can be connected to a trackside power supply network.

[0028] According to the invention, such a vehicle is designed in such a way that, when the vehicle is traveling in a section of the route where energy feedback into the trackside power supply network is not permitted, the vehicle's drive can be operated as an electrodynamic brake during braking and can feed electrical braking energy into a DC link, energy can be extracted from the DC link by feeding a load current into a vehicle-side load, and energy feedback from the DC link into the power supply network is blocked.

[0029] Regarding the advantages of the vehicle according to the invention and its advantageous embodiments, reference is made to the above explanations in connection with the method according to the invention and its advantageous embodiments. It is particularly advantageous if the vehicle is operated as described above in connection with the method according to the invention or is designed for operation according to the method described above.

[0030] According to the invention, the vehicle has an internal converter which is connected between the DC link and the vehicle-side load and is designed to feed the load current from the DC link into the vehicle-side load.

[0031] Alternatively or additionally, it may be advantageously provided that the vehicle has a grid-side converter that connects or can at least connect the DC intermediate circuit to the trackside power supply network and is blocked or blocked in the direction of energy return during braking operation in the aforementioned track section where energy feedback into the trackside power supply network is not permitted.

[0032] According to the invention, the vehicle has a control device or control module which is connected to the internal converter and, in the presence of a blocking signal, in particular an island grid signal, which indicates driving on a section of track without the possibility of energy recuperation, controls the internal converter to draw a target load current, which has been determined using a braking force specification, and to set the load current higher than the target load current if the DC link voltage exceeds a predetermined maximum voltage value (Umax).

[0033] The increase in load current, or the difference between the increased load current and the nominal load current, is preferably proportional to the difference between the value of the DC link voltage and the maximum voltage value, i.e., in other words, proportional to the voltage amount by which the DC link voltage exceeds the maximum voltage value.

[0034] The control unit is preferably also connected to the grid-side converter and designed to block the grid-side converter in the direction of energy return when the blocking signal is present. If the DC link voltage falls below a predetermined minimum voltage value, energy is preferably fed into the trackside power supply network even during braking.

[0035] The grid-side energy or grid current that the grid-side converter feeds into the DC link during braking operation is preferably proportional to the difference between the minimum voltage value and the level of the DC link voltage, i.e., in other words, proportional to the voltage amount by which the DC link voltage falls below the minimum voltage value.

[0036] Alternatively or additionally, a first control module may be present which, in the event of a blocking signal indicating that a section of track without energy recuperation is being traversed, controls the internal converter to draw the load current from the DC link.

[0037] The first control module, with regard to controlling the internal inverter, preferably operates in the same way as the control device described above.

[0038] The first control module can, for example, be implemented as a software module in the control software of a central vehicle control unit or in the control software of the internal inverter.

[0039] Alternatively or additionally, a second control module can be provided, which is designed to block the grid-side inverter in the energy return direction when the blocking signal is present. The second control module preferably controls the grid-side inverter in such a way that it feeds grid-side energy into the DC link even during braking, provided the DC link voltage falls below a predetermined minimum value.

[0040] The second control module, with regard to controlling the grid-side inverter, preferably operates in the same way as the control device described above.

[0041] The second control module can, for example, be implemented as a software module in the control software of a central vehicle control unit or in the control software of the grid-side inverter.

[0042] The first and second control modules preferably operate independently of each other.

[0043] The invention is explained in more detail below using exemplary embodiments, including the following: Figure 1 shows a first embodiment of a rail vehicle according to the invention, Figure 2 shows a block diagram illustrating exemplary process steps for limiting the DC link voltage during braking operation, Figure 3 shows a block diagram illustrating exemplary process steps for increasing the DC link voltage during braking operation, Figures 4-7 show further embodiments of rail vehicles according to the invention.

[0044] For the sake of clarity, the same reference symbols are used in the figures for identical or comparable components.

[0045] The Figure 1Figure 1 shows an embodiment of a rail vehicle 10 equipped with a pantograph 20 for connection to a trackside power supply network 30. The pantograph 20 is connected via a transformer 40 to a grid-side converter 50. The grid-side converter 50 is preferably a four-quadrant converter.

[0046] A DC link 60 connects the grid-side converter 50 to a drive 70. The drive 70 comprises, for example, one or more motors 71, which are connected to the DC link 60 via one or more drive-side converters 72, such as pulse inverters.

[0047] In the embodiment according to Figure 1An internal converter 80 is also connected to the DC link 60, which connects the DC link 60 to an electrical load in the form of an electrical energy storage device 90. The electrical energy storage device 90 is preferably a battery or an electrical capacitor. The internal converter 80 is preferably a DC / DC converter (DC voltage controller).

[0048] The internal converter 80 and the grid-side converter 50 are controlled by a control unit 100, which is connected to both converters 50 and 80. The control unit 100 receives a voltage measurement at a measuring input, indicating the DC link voltage Uzk of the DC link 60. At a control signal input, it receives a control signal ST, which indicates whether or not energy feedback into the trackside power supply network 30 is permitted in the currently traversed track section. The control unit can also receive a braking force value BKA at the control signal input, which defines a target braking force Fsoll specified for the drive 70 during braking.

[0049] During operation of the rail vehicle 10, the drive 70 can be supplied with electrical energy from the trackside power supply network 30. Alternatively or additionally, the drive 70 can be operated with electrical energy from the energy storage device 90. The control unit 100 controls the energy draw, preferably taking into account the respective state of charge of the energy storage device 90. It is also possible to simultaneously supply both the drive 70 and charge the energy storage device 90 with energy from the trackside power supply network 30.

[0050] During braking of the rail vehicle 10, the drive 70 is preferably operated as an electrodynamic brake, and its electrical braking energy is fed into the DC link 60. To prevent the DC link voltage Uzk from rising above a permissible level, the control unit 100 preferably operates as follows: If the input control signal ST indicates that energy recuperation into the trackside power supply network 30 is permissible, the electrical braking energy can be fed into the trackside power supply network 30. Alternatively or additionally, the energy storage device 90 can be charged. The charging process is preferably controlled by the control unit 100 taking into account the respective state of charge of the energy storage device 90.

[0051] If the input control signal ST indicates that energy feedback into the trackside power supply network 30 is prohibited, i.e., the control signal ST constitutes a blocking signal, the control unit 100 controls the network-side converter 50 in such a way that feedback is prevented. The internal converter 50 is controlled such that, during braking, a current Izk is drawn from the DC link 60 that corresponds at least approximately to the braking current Ib supplied by the drive 70. This measure keeps the DC link voltage Uzk constant, or at least counteracts any increase in the DC link voltage Uzk.

[0052] It is possible to measure the braking current Ib and regulate the current Izk accordingly. However, it is particularly advantageous to estimate the required load current Ilast, which would have to flow into the energy storage device 90 to maintain a constant DC link voltage Uzk, as a function of the braking force specification BKA, which defines the target braking force Fsoll specified for the drive 70. The target braking force Fsoll can be set, for example, by a train driver by adjusting a brake lever. In such a case, the braking force specification BKA corresponds, for example, to the respective position of the brake lever.

[0053] A block diagram illustrating a possible technical implementation of a braking force-related control of the internal inverter 80 is shown in the Figure 2 depicted. The in Figure 2 The control system shown is based on the idea that at least approximately the following mathematical relationship applies: Wb = Fsoll ⋅ X where Wb describes the braking energy of the drive and X the distance coordinate. Mit V = X / t erhält man Pb = Wb / t = Fsoll ⋅ S / t = Fsoll ⋅ V t = Uzk ⋅ Izk = Ulast ⋅ Isoll and Isoll t = Fsoll ⋅ V t / Ulast where Pb is the braking power, t is the time, V is the speed of the rail vehicle 10, Ulast is the voltage at the energy storage device 90 and Isoll is a nominal load current Isoll that the internal converter 50 is supposed to feed into the energy storage device 90.

[0054] The calculation of the target load current Isoll is carried out according to the exemplary embodiment Figure 2 in two conversion modules of the control unit 100, which are preferably implemented in software.

[0055] The one in Figure 2 The left or first conversion module 110 calculates the braking power based on the respective speed V(t) according to Pb t = Wb / t = Fsoll S / t = Fsoll V t

[0056] The subsequent second conversion module 120 calculates the target load current Isoll taking into account the result of the first conversion module 110, forming a target load current value according to Isoll t = Pb t / Ulast

[0057] Based on the target load current value of the second conversion module 120, the control unit 100 controls the internal converter 50 such that the magnitude of the load current Ilast corresponds to the calculated target load current Isoll. The internal converter 50 thus operates as a current-controlled buck converter.

[0058] Since the mathematical model described above is relatively simple and does not take into account all technical influences and efficiencies, etc., it may happen that the calculated target load current Isoll is too small and the intermediate circuit voltage Uzk increases.

[0059] To prevent the DC link voltage Uzk from rising above a predetermined maximum voltage value Umax, it is considered advantageous if the described control of the internal converter 80 – i.e., its operation as a current-controlled buck converter – only occurs as long as the DC link voltage Uzk remains below the maximum voltage value Umax. For this purpose, in the embodiment according to Figure 2 Additionally, a comparison module 130 is provided, which compares the intermediate circuit voltage Uzk with the maximum voltage value Umax.

[0060] If the comparator module 130 detects that the DC link voltage Uzk exceeds the maximum voltage value Umax, it generates an enable signal FS for a PI controller 140, which is supplied with a differential voltage value dUmax on its input side. The differential voltage value dUmax quantifies the difference between the actual DC link voltage Uzk and the maximum voltage value Umax and is generated by a differential generator 150.

[0061] If the enable signal FS is present, the PI controller 140 generates a current differential value dI at its output, which is proportional to the determined differential voltage value dUmax. The current differential value dI undergoes a sign change by a multiplier 160 and, after sign correction, is added to the target load current value of the second conversion module 120 in an adder 170, thereby increasing the resulting load current Ilast. Therefore: Ilast = Isoll + dI .

[0062] The components described ensure that if the maximum voltage value Umax is exceeded, the load current Ilast increases and the intermediate circuit voltage Uzk is thereby reduced, because the comparator module 130 activates a voltage regulation.

[0063] Since - as already mentioned - the mathematical model described above is relatively simple, it can also happen that the calculated target load current Isoll is too high and the intermediate circuit voltage Uzk drops.

[0064] To prevent the DC link voltage Uzk from becoming too low, the control unit 100 also monitors the DC link 60 to ensure that the DC link voltage Uzk falls below a predetermined minimum voltage value Umin. If it detects that the voltage has fallen below the minimum value Umin, it controls the grid-side inverter 50 so that it feeds grid-side energy into the DC link 60 even during braking.

[0065] Figure 3 Figure 1 shows an example of a possible technical implementation of grid-side support of the DC link voltage Uzk during braking operation in the form of a block diagram. A further differential generator 200 is visible, which calculates the difference between the actual DC link voltage Uzk and the minimum voltage value Umin, forming a differential value dUmin. The differential value dUmin is fed into a further PI controller 210, which induces a current flow I-netz towards the DC link 60.

[0066] A current Ir or energy flow in the opposite direction is prevented by a backfeed barrier 220 if the DC link voltage Uzk exceeds the minimum voltage Umin. The backfeed barrier 220 can be integrated into the control unit 100 or an internal control function of the grid-side converter 50.

[0067] The components 110, 120, 130, 140, 150, 160, 170, 200, 210 and 220 described above are preferably formed by software modules of a control program SPM, which is stored in a memory 101 of the control unit 100 and, when executed by a computing unit 102 of the control unit 100, performs the described process steps (see Figure 1 ).

[0068] The Figure 4 Figure 10 shows a second embodiment of a rail vehicle according to the invention. In the embodiment according to Figure 10, Figure 4 Energy feedback into the trackside power supply network 30 is permanently blocked by a diode 51 between the grid-side converter 50 and the DC link 60. Therefore, controlling the grid-side converter 50 to block energy feedback is not necessary. Otherwise, the above explanations apply in connection with the Figures 1 to 3in the embodiment according to Figure 4 accordingly.

[0069] The Figure 5 shows a third embodiment of a rail vehicle according to the invention 10. In the embodiment according to Figure 5 An ohmic resistor 300 is connected to the internal converter 80 as a load, converting the electrical braking energy into heat. Instead of a DC / DC converter, an inverter can also be used as the internal converter 80, for example, which supplies the ohmic resistor 300 with alternating current. Otherwise, the above explanations apply in connection with the Figures 1 to 4 in the embodiment according to Figure 5 accordingly.

[0070] The Figure 6 A fourth embodiment of a rail vehicle according to the invention is shown 10. In the embodiment according to Figure 6Both an ohmic resistor 300 and a battery 310 are connected as loads to the internal inverter 80. By opening and closing two switches S1 and S2, the control unit 100 can selectively store the electrical braking energy or convert it into heat, for example, when the battery 310 is fully charged. Otherwise, the above explanations apply in connection with the Figures 1 to 5 in the embodiment shown in Figure 6.

[0071] The Figure 7 shows a fifth embodiment of a rail vehicle according to the invention 10. In the embodiment according to Figure 7 A first control module 400 is provided for controlling the internal converter 80, and a second control module 410, independent of the first control module 400, is provided for controlling the grid-side converter 50.

[0072] The first control module 400 preferably controls the internal inverter 80 in the same way as in the embodiments according to the Figures 1 to 6 The control unit 100 controls the internal inverter 80. The first control module 400 can be implemented as a software module in the control software of the internal inverter 80 or in the control software of a central vehicle control unit.

[0073] The second control module 410 preferably controls the grid-side converter 50 in the same way as in the embodiments according to the Figures 1 to 6 The control unit 100 controls the grid-side inverter 50. The second control module 410 can be implemented as a software module in the control software of the grid-side inverter 50 or in the control software of a central vehicle control unit.

[0074] Alternatively, the two independently operating control modules 400 and 410 can be formed by software modules that are stored in the memory 101 of the control unit 100 according to Figure 1 , for example as program components of the SPM control program, are stored and, when executed by the computing unit 102 of the control unit 100, perform the described process steps. The control unit 100 can, for example, be a vehicle control unit or a component of a vehicle control unit.

[0075] Furthermore, the above explanations apply in connection with the Figures 1 to 6 in the embodiment shown in Figure 7.

[0076] Finally, it should be mentioned that the features of all the embodiments described above can be combined with each other in any way to form further embodiments.

Claims

1. Method for operating a vehicle (10) connected to a track-side energy supply network (30), wherein, during a braking mode within a track section with unauthorised energy feedback into the energy supply network (30), - a drive (70) of the vehicle (10) is operated as an electrodynamic brake and electrical braking energy of the drive (70) is fed into a DC intermediate circuit (60) of the vehicle, - energy is taken from the DC intermediate circuit (60) by feeding a load current (Iload) into a vehicle-side load (90, 300, 310), and - an energy feedback from the DC intermediate circuit (60) into the energy supply network (30) is blocked, - the level of load current (Iload) is adjusted depending on a specified braking force (BKA), which specifies a braking force predetermined for the drive (70) and to be exerted by the drive, and - the electrical braking power (Pb) of the drive (70) is calculated depending on the specified braking force (BKA) and a target load current (Itarget) is calculated based on the calculated braking power (Pb), characterised in that - an internal converter (80) connected between the DC intermediate circuit (60) and the vehicle-side load (90, 300, 310) is controlled depending on the calculated target load current (Itarget), - wherein the internal converter (80) is operated such that the load current (Iload) corresponds to the calculated target load current (Itarget), provided the intermediate circuit voltage (Uzk) falls below a predefined maximum voltage value (Umax), and - wherein the load current (Iload) is adjusted to be greater than the calculated target load current (Itarget) if the intermediate circuit voltage (Uzk) exceeds the predefined maximum voltage value (Umax).

2. Method according to claim 1, characterised in that the calculation of the target load current (Itarget) is performed such that the power drain, caused by the target load current (Itarget), from the DC intermediate circuit (60) corresponds to the braking power (Pb) that is fed by the drive (70) into the DC intermediate circuit (60) according to the specified braking force (BKA).

3. Method according to claim 1, characterised in that - a difference voltage value (dUmax) is ascertained which quantitively specifies the exceedance of the maximum voltage value (Umax), and - the load current (Iload) is adjusted to be greater than the target load current (Itarget) by a current difference (dI) which is proportional to the ascertained difference voltage value (dUmax).

4. Method according to claim 3, characterised in that the current difference (dI) is ascertained using a PI controller (140).

5. Method according to one of the preceding claims, characterised in that - the vehicle (10) has a network-side converter (50), which connects or at least can connect the DC intermediate circuit (60) to the track-side energy supply network (30), and - the energy feedback from the DC intermediate circuit (60) into the energy supply network (30) is blocked in that the network-side converter (50) is blocked in the feedback direction.

6. Method according to claim 5, characterised in that the network-side converter (50) is actuated such that network-side energy is also fed into the DC intermediate circuit (60) during the braking mode, provided that the intermediate circuit voltage (Uzk) falls below a predefined minimum voltage value (Umin).

7. Method according to one of the preceding claims, characterised in that the network-side energy fed into the DC intermediate circuit (60) by the network-side converter (50) during the braking mode is proportional to the voltage value by which the intermediate circuit voltage (Uzk) falls below the minimum voltage value (Umin).

8. Method according to one of the preceding claims, characterised in that - an energy feedback in the direction of the track-side energy supply network (30) during vehicle (10) braking is permitted in a track section with authorised energy feedback, - wherein the energy feedback in the direction of the track-side energy supply network (30) takes place by way of actuation of the network-side converter (50).

9. Method according to one of the preceding claims, characterised in that the internal converter (80) is a DC / DC converter.

10. Vehicle (10) with a current collector (20) which can be connected to a track-side energy supply network (30), wherein while the vehicle (10) is travelling in a track section, in which an energy feedback into the track-side energy supply network (30) is unauthorised, - during the braking mode, a drive (70) of the vehicle (10) can be operated as an electrodynamic brake and electrical braking energy can be fed into a DC intermediate circuit (60), - energy can be taken from the DC intermediate circuit (60) by feeding a load current (Iload) into a vehicle-side load (90, 300, 310), and - an energy feedback into the energy supply network (30) is blocked by the DC intermediate circuit (60), characterised in that - the vehicle (10) has an internal converter (80) which is connected between the DC intermediate circuit (60) and the vehicle-side load (90, 300, 310) and is designed to feed the load current (Iload) into the vehicle-side load (90, 300, 310), and - the vehicle (10) has a control facility (100) or a control module (400) which is connected to the internal converter (80) and, in the presence of a blocking signal (ST) which displays an instance of traveling a track section without the possibility of energy feedback, actuates the internal converter (80) such that it takes a target load current that has been ascertained using a specified braking force and adjusts the load current (Iload) to be greater than the target load current if the intermediate circuit voltage (Uzk) exceeds a predefined maximum voltage value (Umax).

11. Vehicle (10) according to claim 10, characterised in that - a network-side converter (50) is present which is connected between the DC intermediate circuit (60) and the energy supply network (30), and - the vehicle (10) has a control facility (100) or a control module (410) which is connected to the network-side converter (50) and, in the presence of a blocking signal (ST) which displays an instance of traveling a track section without the possibility of energy feedback, actuates the network-side converter (50) such that it blocks energy flow in the direction of energy feedback and during braking mode of the vehicle, feeds energy into the DC intermediate circuit (60) provided that the intermediate circuit voltage falls below a predefined minimum voltage value (Umin).

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