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 to power an on-board electrical system.

[0005] However, for various reasons, it is not possible to use this onboard battery to power the starter. When the starter is powered, a high current flows through it, resulting in a voltage drop in the battery supplying the starter. Some onboard equipment cannot tolerate such a voltage drop, and this significant voltage drop can lead, for example, to malfunction or even damage to this equipment. Therefore, the starter should be powered not by the onboard 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 considering the large number of systems and batteries.

[0007] An object 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 with 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 an internal combustion engine and a starting device configured to start the internal combustion engine, the starting device being connected to the traction battery by a power supply connection arranged to supply the starting device by a starting voltage strictly lower than the traction voltage.

[0009] Indeed, the traction system according to the invention allows the combustion engine's starting device to be powered by the traction battery already present in the traction system. In particular, arranging the power supply connection so as to power the starting device with the starting voltage makes it possible to obtain a particularly lightweight traction system. The traction system according to the invention notably eliminates the need for 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 a traction battery with a voltage of at least 800 V becomes possible in railway vehicles because the capacity and voltage of this battery are very high. Consequently, the power supply to the starting device has little or no effect 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 features, taken individually 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 cell has a voltage having a nominal value approximately equal to 1.2 V;

[0016] - the power supply connection includes a first cable connecting the device to starting at an intermediate terminal of the traction battery, the intermediate terminal being electrically connected to one or more battery banks, referred to as the starting power bank, between two adjacent battery elements of the plurality of battery elements connected in series of said starting power bank;

[0017] - the power supply connection includes a second cable connecting the device to starting at one end of said starting power supply 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 tension and being connected to the electric traction motor;

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

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

[0021] - the traction battery includes a controller configured to allow a powering the starting device with the starting voltage when the traction voltage is above a predetermined threshold, and / or when the traction battery temperature is within a predetermined temperature range;

[0022] - the starting device includes a starting motor configured for 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 power an on-board network of the railway vehicle.

[0025] The features and advantages of the invention will become apparent from the following description, given solely by way of non-limiting example, and made with reference to the accompanying drawing in which:

[0026] - [Fig. 1] Fig. 1 is a schematic view of part of a railway vehicle including a traction system according to the invention.

[0027] With reference to [Fig.1], a railway vehicle 10 includes a traction system 12 configured to pull 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 includes, for example, an on-board battery 14 and an on-board network 16. The on-board battery 14 is in particular separate 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 includes an electric traction motor 18, a combustion engine 20, a traction battery 22, a traction bus 24, a starting device 26 and a power link 28.

[0031] The electric traction motor 18 is configured to pull the rail vehicle. In particular, the electric traction motor 18 is connected to the traction battery 22 via 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, electrically powering 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 pull the railway vehicle 10 and / or forms a generator configured to electrically power 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 specifically configured to provide a direct current. The traction battery 22 has, in particular, a capacity of at least 50 kWh, preferably at least 100 kWh, and even more preferably several hundred kWh.

[0038] The traction battery 22 has a 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 above 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 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 one 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 making it possible to use the traction battery 22 without risking, for example, a significant drop in traction voltage.

[0043] The traction battery 22 includes in particular two voltage terminals 30, 32. The two voltage terminals 30 and 32 present the traction voltage between them. In particular, the two voltage terminals 30 and 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, and even more preferably greater than or equal to 12.

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

[0046] Each battery bank 34 is preferably identical to each other.

[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 an 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 elements 36 connected in series, in particular between the ends of the respective battery bank 34. For example, with reference to [Fig. 1], each battery bank 34 comprises M battery elements 36. The number M is at least 2, preferably at least 10, and even 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 elements 36.

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

[0051] For example, each battery cell 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 cells 36.

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

[0053] The traction battery 22 further includes, 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 cell 36 to control, for example, its voltage and / or the temperatures of the battery cells 36.

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

[0055] According to one example, the controller 38 is configured to allow power 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 temperature range.

[0056] The traction battery 22 further comprises, for example, at least one switch 40, 42, configured to electrically isolate 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 isolate the voltage terminal 30 from the battery banks 34, and a second switch 42 configured to electrically isolate the voltage terminal 32 from the battery banks 34. The switch or switches 40, 42 are, for example, controlled by the controller 38.

[0057] In one example, the switch or switches 40, 42 are integrated into a control cabinet (or "switch cabinet"). In another example, the switch or switches 40, 42 are contactors.

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

[0059] For example, the traction battery 22 further includes, for the one 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 in particular 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 mass or earth.

[0060] According to one example, the traction battery 22 includes, for the one 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 keeping in particular 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 charging terminal.

[0062] As an optional addition and not shown, the traction bus 24 connects the voltage terminals 30, 32 further 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 supplied with a current 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 supplied with power for a duration of 10 s or less. In particular, the starting device 26 is configured to use very little electrical energy for starting the combustion engine 20 compared to to a total traction battery energy 22, including a charge several orders of magnitude lower than the total energy.

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

[0065] In addition, the starting device 26 includes 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 link 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 notably 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 or more battery banks 34, referred to as the starting power bank, between two adjacent battery cells 36 of that starting power bank. In the example of [Fig. 1], the starting power bank is battery bank 34-1.

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

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

[0073] For example, the second cable 50 is connected to a bus linking the respective ends of the set of battery banks 34, connected in parallel, to the voltage terminal 32, particularly 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 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 without the second switch 42, the second cable 50 is preferably connected to a section of a bus which links, without intermediate elements, the voltage terminal 32 to the ends of the 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, using the traction battery 22, which has a traction voltage of 800 V or higher, to start the combustion engine 20 eliminates the need for a dedicated battery to power the starting device 26. This is especially advantageous because the traction battery 22 has a high voltage and preferably a high capacity. For example, powering the starting device 26 from the onboard battery 14 is not possible for these reasons.

[0080] Furthermore, a variation in traction voltage of the traction battery 22 when the starting device 26 is powered is very small considering 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, particularly the on-board network 16, some of which is sensitive to variations in the supply voltage. For example, when the traction voltage varies, particularly when the starting device 26 is powered by the traction battery 22, the equipment of the on-board network 16 is not affected by this variation, however small, in voltage.

Claims

Demands

1. A railway vehicle (10), comprising a traction system (12) including an electric traction motor (18), and a traction battery (22) 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 link (28) arranged to supply the starting device (26) with a starting voltage strictly lower than the traction voltage, characterized in that the vehicle further comprises an on-board battery (14), separate from the traction battery (22), configured to supply an on-board network (16) of the railway vehicle (10), and in that the traction battery (22) has a traction voltage having a nominal value greater than or equal to 800 V.

2. Railway vehicle (10) according to claim 1, wherein the starting voltage is between 10 and 30 V.

3. Rail vehicle (10) 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 elements (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 respect to each other.

4. Railway vehicle (10) according to claim 3, wherein the power link (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 or more of the battery bank(s) (34-1, 34-2, 34-N), referred to as the starting power bank, between two adjacent battery elements of the plurality of battery elements (36-1, 36-2, 36-M) connected in series to said starting power bank.

5. A railway vehicle (10) according to claim 4, wherein the power supply link (28) comprises a second cable (50) connecting the starting device (26) to one end of said bench of starting power supply, the end preferably having a voltage substantially equal to zero with respect to ground.

6. Railway vehicle (10) according to any one of the preceding claims, 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. Rail vehicle (10) according to claim 6, wherein the traction battery (22) comprises at least one switch (40, 42) configured to electrically isolate one of the voltage terminals (30, 32) of the battery bank(s) (34-1, 34-2, 34-N), and / or wherein the traction battery (22) comprises, for the battery bank(s) (34-1, 34-2, 34-N), a fuse (44) or a switch configured to electrically isolate this battery bank (34-1, 34-2, 34-N) from one of the voltage terminals (30, 32).

8. Rail vehicle (10) according to any one of the preceding claims, wherein the traction battery (22) includes a controller (38) configured to allow the starting device (26) to be powered by the starting voltage when the traction voltage is above a predetermined threshold, and / or when a temperature of the traction battery (22) is within a predetermined temperature range.

Images