Traction system of a railway vehicle and associated railway vehicle

Abstract

Traction system of a railway vehicle and associated railway vehicle. Traction system (12) of a railway vehicle (10) comprising an electric traction motor (18), a traction battery (22) having a traction voltage of 800 V or higher, the traction battery (22) being connected to the electric traction motor (18), the traction system (12) further comprising an internal combustion engine (20) and a starting device (26) configured to start the internal combustion engine (20), the starting device (26) being connected to the traction battery (22) by a power supply link (28) arranged to supply the starting device (26) with a starting voltage strictly lower than the traction voltage. Figure for the abbreviation: Figure 1

Description

Title of the invention: Traction system for a railway vehicle and associated railway vehicle

[0001] The present invention relates to a traction system for a railway vehicle.

[0002] The invention further relates to a railway vehicle comprising such a traction system.

[0003] The invention relates to the field of railway vehicles, in particular hybrid railway vehicles. Hybrid railway vehicles comprise, for traction, a combustion engine and an electric motor powered for example by a high-capacity traction battery.

[0004] To start the combustion engine, some railway vehicles include an electric starter. The starter is powered by a battery dedicated to powering this starter. In addition, such railway vehicles include, for example, an on-board battery for powering an on-board network.

[0005] However, it is not possible, for various reasons, to use this on-board battery to power the starter. Indeed, when powering the starter, a strong current passes through the starter, resulting in a drop in the voltage of the battery powering the starter. Some on-board equipment does not tolerate such a voltage drop, and this strong voltage drop results, for example, in a malfunction, or even damage, of this equipment. Consequently, the starter should be powered not by the on-board battery, but by the dedicated battery.

[0006] Such a hybrid rail vehicle, comprising a combustion engine and an electric motor for traction, is relatively heavy given the large number of systems and batteries.

[0007] An aim of the invention is then to obtain a traction system for a railway vehicle comprising an electric traction motor and a combustion engine, which is lighter and / or which comprises a reduced number of components.

[0008] To this end, the present invention relates to a traction system for a railway vehicle comprising an electric traction motor, a traction battery having a traction voltage having a nominal value greater than or equal to 800 V, the traction battery being connected to the electric traction motor, the traction system further comprising a combustion engine and a starting device configured to start the combustion engine, the starting device being connected to the traction battery by a power supply connection arranged to supply the starting device with a starting voltage strictly lower than the traction tension.

[0009] Indeed, the traction system according to the invention makes it possible to power the starting device of the combustion engine by the traction battery which is already present in the traction system. In particular, arranging the power supply connection so as to power the starting device by the starting voltage makes it possible to obtain a particularly lightweight traction system. The traction system according to the invention makes it possible in particular to dispense with a battery dedicated exclusively to powering the starting device.

[0010] Also, the use of the traction battery makes it easier to recharge the batteries, because no battery dedicated solely to powering the starting device is recharged.

[0011] Finally, the use of the traction battery having a voltage of at least 800 V becomes possible in the context of railway vehicles, because the capacity of this battery and its voltage are very high. Consequently, the power supply of the starting device does not influence or only very little on the traction voltage of the traction battery.

[0012] According to other advantageous aspects of the invention, the traction system comprises one or more of the following characteristics, taken in isolation or in all technically possible combinations:

[0013] - the starting voltage is between 10 and 30 V;

[0014] - the traction battery comprises at least one battery bank comprising a plurality of battery elements connected in series, preferably the traction battery comprising several battery banks connected in parallel with each other;

[0015] - each battery element has a voltage having a nominal value sen possibly equal to 1.2 V;

[0016] - the power supply connection comprises a first cable connecting the device of starting at an intermediate terminal of the traction battery, the intermediate terminal being electrically connected to one of the battery bank(s), called the starting power bank, between two neighboring battery elements of the plurality of battery elements connected in series to said starting power bank;

[0017] - the power supply connection comprises a second cable connecting the device of starting at one end of said starting power bank, the end preferably having a voltage substantially equal to zero with respect to ground;

[0018] - the traction battery comprises two voltage terminals having between them the traction voltage and being connected to the electric traction motor;

[0019] - the traction battery comprises at least one switch configured to separate electrically one of the voltage terminals of the battery bank(s), and / or in wherein the traction battery comprises, for the or each battery bank, a fuse or switch configured to electrically separate that battery bank from one of the voltage terminals;

[0020] - the traction battery is a lithium-ion battery;

[0021] - the traction battery comprises a controller configured to authorize a power supply nutrition of the starting device by the starting voltage when the traction voltage is higher than a predetermined threshold, and / or when a temperature of the traction battery is within a predetermined range of temperatures;

[0022] - the starting device comprises a starting motor configured to start the combustion engine.

[0023] The present invention also relates to a railway vehicle comprising a traction system as described above.

[0024] According to an advantageous aspect of the invention, the railway vehicle further comprises an on-board battery, separate from the traction battery, configured to supply an on-board network of the railway vehicle.

[0025] The characteristics and advantages of the invention will appear on reading the description which follows, given solely by way of non-limiting example, and made with reference to the appended drawing in which:

[0026] - [Fig.l] [Fig.l] is a schematic view of part of a railway vehicle comprising a traction system according to the invention.

[0027] With reference to [Fig.l], a railway vehicle 10 comprises a traction system 12 configured to tow the railway vehicle 10.

[0028] The railway vehicle 10 is in particular a hybrid vehicle, comprising in particular two traction motors of different types.

[0029] The railway vehicle 10 further comprises, for example, an on-board battery 14, and an on-board network 16. The on-board battery 14 is in particular distinct from the traction system 12. The on-board battery 14 is in particular configured to supply the on-board network 16, in particular with a low voltage, such as a voltage substantially equal to 24 V.

[0030] The traction system 12 comprises an electric traction motor 18, a combustion engine 20, a traction battery 22, a traction bus 24, a starting device 26 and a power connection 28.

[0031] The electric traction motor 18 is configured to tow the railway vehicle. In particular, the electric traction motor 18 is connected to the traction battery 22 by the traction bus 24.

[0032] The electric traction motor 18 is configured to be powered by a traction voltage from the traction battery 22. As an optional addition, the electric traction motor 18 is configured to operate in recuperative mode, by supplying elec- strictly the traction battery 22.

[0033] The combustion engine 20 is for example a diesel engine. According to one example, the traction system 12 comprises several combustion engines 20.

[0034] The combustion engine 20 is for example configured to tow the railway vehicle 10 and / or forms a generator configured to electrically supply the traction battery 22.

[0035] The combustion engine 20 is configured to be started by the starting device 26.

[0036] The traction battery 22 is preferably a lithium-ion battery.

[0037] The traction battery is in particular configured to provide direct current. The traction battery 22 has in particular a capacity of at least 50 kWh, preferably at least 100 kWh, more preferably several hundred kWh.

[0038] The traction battery 22 has the traction voltage. The traction voltage has a nominal value greater than or equal to 800 V. Preferably, the nominal value is between 800 V and 1000 V.

[0039] By “nominal value” is meant a predetermined voltage value, in particular when the traction battery 22 has a state of charge greater than a predetermined lower threshold.

[0040] The traction voltage has a value strictly greater than a value of a starting voltage with which the starting device 26 is supplied to start the combustion engine 20. Preferably, the traction voltage has an order of magnitude different from an order of magnitude of the value of the starting voltage.

[0041] Preferably, the traction battery 22 has a very high electrical charge, in particular one or more orders of magnitude higher than an order of magnitude of an electrical charge used by the starting device 26 to start the combustion engine 20.

[0042] This has the particular effect of being able to use the traction battery 22 without risking, for example, a significant drop in the traction voltage.

[0043] The traction battery 22 comprises in particular two voltage terminals 30, 32. The two voltage terminals 30, 32 have the traction voltage between them. In particular, the two voltage terminals 30, 32 are connected to the electric traction motor 18.

[0044] The traction battery 22 further comprises at least one battery bank 34. Preferably, the traction battery 22 comprises several battery banks 34 connected in parallel with each other, for example N battery banks. The number N is greater than or equal to 2. Preferably, the number N is greater than or equal to 10, more preferably still greater than or equal to 12.

[0045] For example, with reference to [Fig. 1], the traction battery 22 comprises the bank of 34-1 batteries, 34-2 battery bank and 34-N battery bank.

[0046] Each battery bank 34 is preferably identical to one another.

[0047] Each end of a corresponding battery bank 34 is electrically connected to one of the two voltage terminals 30, 32. Preferably, each end of a battery bank 34 is directly connected to the respective voltage terminal, i.e. in particular without any intermediate element between the end and the respective terminal 30, 32 other than a fuse and / or a switch.

[0048] Each battery bank 34 comprises a plurality of battery cells 36 connected in series, in particular between the ends of the respective battery bank 34. For example, with reference to [Fig.l], each battery bank 34 comprises M battery cells 36. The number M is at least 2, preferably at least 10, more preferably at least 20 or equal to 20.

[0049] According to one example, the traction battery 22 comprises twelve battery banks 34, and each battery bank 34 comprises twenty battery cells 36.

[0050] For example, battery bank 34-1 comprises battery cell 36-1, battery cell 36-2 and battery cell 36-M. Preferably, each battery bank 34 comprises the same number of battery cells 36.

[0051] For example, each battery element 36 has a voltage having a predetermined nominal value, for example substantially equal to 1.2 V. In this example, to obtain the traction voltage greater than or equal to 800 V, each battery bank 34 comprises for example more than 650 battery elements 36.

[0052] According to one example, each battery element 36 comprises a nominal capacity equal to 60 Ah.

[0053] The traction battery 22 further comprises, for example, a controller 38 configured to control the operation of the traction battery 22. In particular, the controller 38 is connected to each battery element 36 to control, for example, its voltage and / or temperatures of the battery elements 36.

[0054] According to one example, the controller 38 is configured to authorize power supply to the starting device 26 only when the traction voltage is greater than a predetermined threshold.

[0055] According to one example, the controller 38 is configured to authorize a power supply to the starting device 26 only when a temperature of the traction battery 22, and in particular of the battery elements 36, is within a predetermined range of temperatures.

[0056] The traction battery 22 further comprises, for example, at least one switch 40, 42, configured to electrically separate one of the voltage terminals 30, 32 from the battery bank(s) 34. For example, with reference to [Fig. 1], the traction battery 22 comprises a first switch 40 configured to electrically separate the voltage terminal 30 of the battery banks 34, and a second switch 42 configured to electrically separate the voltage terminal 32 of the battery banks 34. The or each switch 40, 42 is for example controlled by the controller 38.

[0057] According to one example, the or each switch 40, 42 is integrated into a control cabinet (or “switch cabinet” in English). According to one example, the or each switch 40, 42 is a contactor.

[0058] Preferably, the or each switch 40, 42 is configured to be open when the starting device 26 starts the combustion engine 20.

[0059] For example, the traction battery 22 further comprises, for the or each battery bank 34, at least one fuse 44 configured to separate this battery bank 34, preferably only this battery bank 34, from the voltage terminal 32 when a current exceeds a predetermined threshold, while notably maintaining a connection of the other battery banks 34 to the voltage terminal 32. In this example, the voltage terminal 32 preferably has a voltage substantially equal to zero with respect to ground or earth.

[0060] According to one example, the traction battery 22 comprises, for the or each battery bank 34, a specific switch, not shown, configured to separate this battery bank 34 from one of the voltage terminals 30, 32, preferably only this battery bank 34, while notably maintaining a connection of the other battery banks 34 to the corresponding voltage terminal 30, 32.

[0061] The traction bus 24 connects in particular the voltage terminals 30, 32 to the electric traction motor 18 and / or to a voltage source, not shown, for recharging the traction battery 22. According to one example, the voltage source is a recharging terminal.

[0062] As an optional and not shown addition, the traction bus 24 further connects the voltage terminals 30, 32 to the combustion engine 20 for recharging the traction battery 22, when the combustion engine 20 is operating as a generator.

[0063] The starting device 26 is configured to start the combustion engine 20. For example, the starting device 26 is configured to be powered by a current of between 1500 A and 2000 A for starting the combustion engine 20. Preferably, the starting device 26 is configured to start the combustion engine 20 when it is powered for a duration less than or equal to 10 s. In particular, the starting device 26 is configured to use for starting the combustion engine 20 a very low electrical energy compared to a total energy of the traction battery 22, in particular a charge several orders of magnitude lower than the total energy.

[0064] The starting device 26 comprises for example a starting motor 46, which is in particular an electric motor configured to transmit a torque mechanical to the combustion engine 20 to start it.

[0065] In addition, the starting device 26 comprises an electrical circuit and / or a controller, not shown, configured to control the operation of the starting motor 46.

[0066] According to the invention, the power supply connection 28 is arranged to supply the starting device 26, and in particular the starting motor 46, with the starting voltage strictly lower than the traction voltage.

[0067] By "power supply connection 28 arranged to supply the starting device", it is understood in particular that the power supply connection 28 forms a voltage divider. In particular, the power supply connection 28 is arranged to derive a voltage strictly lower than the traction voltage, namely the starting voltage, from the traction voltage which is in particular present between two ends of each battery bank 34.

[0068] For example, the starting voltage is between 10 V and 30 V, preferably substantially equal to 12 V or 24 V.

[0069] Preferably, the power supply link 28 comprises a first cable 48 and a second cable 50.

[0070] The first cable 48 connects the starting device 26 to an intermediate terminal 52 of the traction battery 22. The intermediate terminal 52 is electrically connected to one of the battery bank(s) 34, called the starting power bank, between two battery elements 36 adjacent to this starting power bank. In the example of [Fig.l], the starting power bank is the battery bank 34-1.

[0071] The second cable 50 is preferably electrically connected to one end of the starting power bank.

[0072] For example, the second cable 50 is electrically connected to the end of the starting power bank having a voltage substantially equal to zero with respect to ground or earth. This makes it possible in particular to power the starting device 26 without providing electrical insulation between the traction battery 22 and the starting device 26.

[0073] For example, the second cable 50 is connected to a bus connecting the respective ends of all the battery banks 34, connected in parallel, to the voltage terminal 32, in particular when the second switch 42 is closed.

[0074] For example, the second cable 50 is connected to a section of this bus which connects the second switch 42 to the ends of the set of battery banks 34 or to the fuses 44 arranged at the ends of the battery banks 34. Preferably, this section of said bus is devoid of other electrical elements or connections to other electrical elements, such as capacitors.

[0075] When the traction battery 22 is devoid of the second switch 42, the second cable 50 is preferably connected to a section of a bus which connects, without intermediate elements, the voltage terminal 32 to the ends of the set of battery banks 34 or to the fuses 44 arranged at the ends of the battery banks 34.

[0076] The arrangement of the first and second cables 48, 50 thus forms a voltage divider.

[0077] According to examples not shown, the first cable 48 and / or the second cable 50 includes at least one resistor and / or at least one fuse.

[0078] It is understood that the present invention has a large number of advantages.

[0079] In particular, the fact of using the traction battery 22 having a traction voltage having a value greater than or equal to 800 V for starting the combustion engine 20 makes it possible to dispense with a dedicated battery for supplying the starting device 26. This is particularly advantageous because the traction battery 22 has a high voltage value and preferably a high capacity. For example, such a supply of the starting device 26 is not possible from the on-board battery 14 for these reasons.

[0080] Furthermore, a variation in traction voltage of the traction battery 22 when supplying the starting device 26 is very low given the high capacity of the traction battery 22.

[0081] The use of the on-board battery 14, separate from the traction battery 22, makes it possible to protect on-board equipment, in particular the on-board network 16, some of which are sensitive to a variation in the supply voltage. For example, when the traction voltage varies, in particular when the starting device 26 is powered by power from the traction battery 22, the equipment of the on-board network 16 is not impacted by this variation, even a small one, in the voltage.

Claims

Claims

1. Traction system (12) of a railway vehicle (10) comprising an electric traction motor (18), a traction battery (22) having a traction voltage having a nominal value greater than or equal to 800 V, the traction battery (22) being connected to the electric traction motor (18), the traction system (12) further comprising a combustion engine (20) and a starting device (26) configured to start the combustion engine (20), the starting device (26) being connected to the traction battery (22) by a power supply connection (28) arranged to supply the starting device (26) with a starting voltage strictly lower than the traction voltage.

2. The traction system (12) of claim 1, wherein the starting voltage is between 10 and 30 V.

3. A traction system (12) according to claim 1 or claim 2, wherein the traction battery (22) comprises at least one battery bank (34-1, 34-2, 34-N) comprising a plurality of battery cells (36-1, 36-2, 36-M) connected in series, preferably the traction battery (22) comprising several battery banks (34-1, 34-2, 34-N) connected in parallel with each other.

4. Traction system (12) according to claim 3, wherein the power connection (28) comprises a first cable (48) connecting the starting device (26) to an intermediate terminal (52) of the traction battery (22), the intermediate terminal (52) being electrically connected to one of the battery bank(s) (34-1, 34-2, 34-N), called the starting power bank, between two neighboring battery elements of the plurality of battery elements (36-1, 36-2, 36-M) connected in series to said starting power bank.

5. A traction system (12) according to claim 4, wherein the power link (28) comprises a second cable (50) connecting the starting device (26) to one end of said starting power bank, the end preferably having a voltage substantially equal to zero with respect to ground.

6. A traction system (12) according to any preceding claim, wherein the traction battery (22) comprises two voltage terminals (30, 32) having the traction voltage between them and being connected to the electric traction motor (18).

7. Traction system (12) according to claim 6, wherein the traction battery (22) comprises at least one switch (40, 42) configured to electrically separate one of the voltage terminals (30, 32) from the battery bank(s) (34-1, 34-2, 34-N), and / or wherein the traction battery (22) comprises, for the or each battery bank (34-1, 34-2, 34-N), a fuse (44) or a switch configured to electrically separate this battery bank (34-1, 34-2, 34-N) from one of the voltage terminals (30, 32).

8. A traction system (12) according to any preceding claim, wherein the traction battery (22) comprises a controller (38) configured to authorize a power supply to the starting device (26) by the starting voltage when the traction voltage is greater than a predetermined threshold, and / or when a temperature of the traction battery (22) is within a predetermined range of temperatures.

9. A railway vehicle (10) comprising a traction system (12) according to any one of the preceding claims.

10. Rail vehicle (10) according to claim 9, further comprising an on-board battery (14), separate from the traction battery (22), configured to power an on-board network (16) of the rail vehicle (10).

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