,TagSPECI:The present invention relates to an electrically driven vehicle, in particular a rail vehicle, including at least one electrical device and an assembly, the assembly comprising:
- a plurality of high-voltage electrical apparatuses for powering or controlling the electrical device, and
- an enclosure that is not hermetic with respect to the ambient air, the enclosure containing the electrical apparatuses and defining an inner volume filled with inner air.
The invention also relates to a corresponding method.
A railroad tractive unit, of the electrically driven type, includes, in general on the roof, one or more pantographs and a plurality of high-voltage electrical apparatuses for powering or controlling electrical devices, for example including a motor. The plurality of electrical apparatuses for example comprises a 25 kV/15 kV single-phase circuit breaker, a ground isolator, a single-phase/direct switch, a sensor transformer and/or voltage sensor, a disconnecting switch for the high-voltage line and one or more current transformers and/or one or more current sensors.
For the outside insulating of the electrical apparatuses of the assembly, it is known to insulate them individually using insulating materials whereof the outer shape includes several fins, the electrical apparatuses furthermore being placed so as to obtain sufficient insulating distances between them or relative to the mass of the train or an electric gauge. The insulation distances are important to deal with a polluted environment, for example by conductive or nonconductive dust deposits, rain, snow. Insulators or insulating enclosures equipped with fins are fragile and may be damaged during use, for example by projected rocks or during maintenance operations. Furthermore, the dimensions of the assembly are large.
Document EP-B-1,851,083 describes an assembly in which the electrical apparatuses are at least partially encapsulated in a solid insulation, for example a resin, completed by insulation by a liquid. This makes it possible to eliminate insulators with fins and make the assembly more compact, but also more complex, expensive and difficult to maintain.
Document FR-A-2,697,789 describes an assembly in which the electrical apparatuses form a single block positioned in a hermetic enclosure filled with a dielectric gas, such as sulfur hexafluoride. This also makes it possible to eliminate insulators with fins and obtain a more compact assembly. However, the assembly obtained is more complex to implement and its maintenance requires suitable means.
Lastly, the firm Sécheron has developed an assembly known under the name AC MODBOX® in which the electrical apparatuses are housed in a non-hermetic enclosure filled with air. Such an assembly is easy to implement, but there is a risk of water condensation in the enclosure. Consequently, the insulating distances to be respected are large. The incorporated electrical apparatuses are of the traditional type, to deal with a potentially wet environment. The assembly is relatively bulky and heavy.
One aim of the invention is to provide a vehicle of the aforementioned type, including an assembly that is less bulky, while remaining easy to implement.
To that end, the invention relates to a vehicle of the aforementioned type, wherein the assembly further includes a dehumidifying device capable of producing a flow of air that is less humid than the ambient air, the flow of air emerging in the inner volume.
According to specific embodiments, the vehicle may comprise one or more of the following features, considered alone or according to any technically possible combination(s):
- the dehumidifying device comprises a compressed air unit for producing compressed and dried air from the ambient air, the compressed air unit being designed to supply the vehicle with compressed and dried air, the dehumidifying device comprising at least one channel to withdraw at least a fraction of the compressed and dried air in order to obtain air that is less humid than the ambient air;
- the dehumidifying device comprises a drying unit, the produced flow of air resulting from the drying of a first inner flow of air inside the drying unit;
- the drying unit comprises at least one material absorbing moisture to dry the first inner flow of air;
- the dehumidifying device comprises a heating member for producing a flow of hot air designed to pass through the moisture absorbing material so as to regenerate the moisture absorbing material, the flow of hot air being evacuated outside the enclosure after it passes through the moisture absorbing material;
- the heatingmember is configured to heat a flow of ambient air, the flow of hot air being obtained by heating the flow of ambient air;
- the heating member is configured to heat a second inner flow of air, the flow of hot air being obtained by heating the second inner flow of air;
- the dryingunit comprises at least one cartridge that can be removed from the drying unit, the cartridge containing at least one fraction of the moisture absorbing material, the cartridge being designed to be replaced periodically by another cartridge similar to said cartridge;
- the drying unit comprises a condenser to produce the less humid flow of air by cooling of the first inner flow of air and by condensing water, the removed water being evacuated outside the enclosure;
- the assembly is designed to be connected to an electrical power source by at least one pantograph;
- the electrical apparatuses form a single-piece assembly. The connections between the electrical apparatuses are then internal, which facilitates their integration.
The invention lastly relates to a method for powering or controlling at least one electrical device of an electrically driven vehicle, in particular a rail vehicle, comprising at least one step for powering or controlling the electrical device using a plurality of high-voltage electrical apparatuses situated in an enclosure of the vehicle, the enclosure not being hermetic with respect to the ambient air and defining an inner volume filled with air, the method further including a dehumidifying step capable of producing a flow of air that is less humid than the ambient air, said flow of air emerging in the inner volume.
The invention will be better understood upon reading the following description, provided solely as an example, and done in reference to the appended drawings, in which:
- Figure 1 is a side view diagrammatically showing a rail vehicle according to a first embodiment of the invention;
- Figures 2 to 5 are diagrammatic overall views belonging to rail vehicles according to a second, third, fourth and fifth embodiment of the invention, respectively.
A rail transit car 1 is described in reference to Figure 1. The rail vehicle 1 is for example a railroad tractive unit hitched to other railroad vehicles (not shown) to form a raft.
The rail transit car 1 comprises a body 3, and a pantograph 5 electrically connected to a catenary 7 forming an electrical power source for the rail transit car. The rail transit car 1 also comprises an electrical device 9, for example an electric motor, and an assembly 11 for powering or controlling the electrical device 9.
The body 3 defines a roof 13 of the rail transit car 1.
The assembly 11 comprises an enclosure 15, a plurality of electrical apparatuses 17 situated in the enclosure 15, and a dehumidifying device 19 for dehumidifying the enclosure 15.
The assembly 11 advantageously includes at least one sensor (not shown) to measure a humidity level in the enclosure 15.
The enclosure 15 defines an inner volume 21 around electrical apparatuses 17. The enclosure 15 is non-hermetic. "Non-hermetic" means that the enclosure 15 comprises at least one passage 23 putting the inner volume 21 in fluid communication with the outside of the enclosure.
The enclosure 15 is situated near the roof 13 of the body 3. As an alternative (not shown), it is situated on the roof 13.
Alternatively (not shown), the enclosure 15 is situated inside or below the body 3.
In a known manner, the enclosure 15 for example comprises an aluminum housing and a cover (not shown). The enclosure includes diaphragms (not shown) for the passage of control members or cables. Certain control members (not shown) are for example placed directly in the enclosure 15.
The inner volume 21 is filled with air that will be described as "inner air", as opposed to the ambient air 25 situated outside the enclosure 15.
The aforementioned sensor is configured to measure the humidity level of the inner air of the enclosure 15.
The passage 23 allows the inner air to escape from the enclosure 15 or allows the ambient air 25 to enter the enclosure. The passage 23 is for example a simple opening.
Alternatively, the passage 23 is a valve (not shown). According to another alternative (not shown), the passage 23 results from natural leaks due to an assembly that is non-hermetic by design.
"High-voltage" for example refers to a voltage of at least 1 kV. As an example, the plurality of electrical apparatuses 17 comprises, in a manner known in itself, elements (not shown) from among the following list:
- a single-phase circuit breaker working at 25 kV/15 kV,
- a ground isolator,
-a single-phase/direct switch,
- a sensor transformer and/or voltage sensor,
- a disconnecting switch for the high-voltage line, and
- one or more current transformers and/or one or more current sensors.
At least one of the electrical apparatuses 17 is electrically connected to the electrical device 9.
In the first embodiment, the dehumidifier 19 is a compressed air unit 20 for the rail transit car 1. The dehumidifier 19 comprises a compressor and a drier (not shown) to produce a flow of compressed air 27 for the rail transit car 1 from a flow of ambient air 29. The dehumidifier 19 further comprises a channel 31 for bringing a flow of air 33 into the inner volume of the enclosure 15. Except for a terminal part of the channel 31, the dehumidifier 19 is situated outside the enclosure 15.
The flow of air 33 is made up of a fraction of the compressed and dried air produced by the compressed air unit.
The produced flow of air 33 is less humid than the ambient air 25. For example, the dew point of the produced flow of air 33 is below the ambient temperature, preferably below -25°C.
The channel 31 comprises expansion members to adjust the pressure and flow rate of the flow of air 33 emerging in the enclosure 15.
The operation of the rail transit car 1 and the assembly 11 will now be described.
The electrical apparatuses 17 are electrically powered from the catenary 7 via the pantograph 5. Then, at least one of the electrical apparatuses 17 powers the electrical device 9, which in the example is a motor.
From the ambient air 25, the dehumidifier 19 produces compressed and dried air designed to operate various equipment (not shown) of the rail transit car 1. Part of the compressed and dried air produced by the dehumidifier 19 passes through the channel 31 and emerges in the inner volume 21 of the enclosure 15. This produces a mixture of air in the inner volume 21. The compressed and dried air contribution in the enclosure 15 creates a slight overpressure in the enclosure. The overpressure causes a fraction of the inner air to escape through the passage 23 and prevents the entry of ambient air 25.
The addition of air less humid than the ambient air 25 into the enclosure 15 makes it possible to control the humidity level of the inner air at a defined value, comprised between the humidity level of the ambient air 25 and the humidity level of the compressed and dried air produced by the dehumidifier 19. The controlled value can in particular be adjusted by modifying the flow rate of the flow of air 33. The higher the flow rate of the injected air is, the more the control value of the humidity level of the inner air decreases.
According to one particular embodiment, the flow rate of the flow of air 33 is adjusted continuously so as to obtain a predetermined humidity level in the enclosure 15, for example comprised between 40% and 80% relative humidity.
According to another particular embodiment, the flow rate of the flow of air 33 is substantially constant. The flow rate of the flow of air 33 is for example comprised between 10 and 40 Nl/minute. “Nl”, or "normal liters", refers to a quantity of air occupying a volume of 1 liter under normal temperature and pressure conditions (273.15 K and 1 atmosphere).
Owing to the characteristics described above, the humidity level of the inner air is controlled, such that it is possible to reduce the insulation distances of the electrical apparatuses 17. This makes it possible to reduce the dimensions of the enclosure 15. The assembly 11 is therefore less bulky. The withdrawal of part of the compressed and dried air intended for the rail transit car 1 to obtain the flow of air 33 injected into the enclosure 15 is furthermore easy to implement.
Additionally, it is possible to use electrical apparatuses 17 intended for atmospheres less humid than the ambient air 25. This makes it possible to reduce the mass of the assembly 11.
Using part of the compressed and dried air intended for the rail transit car 1 has the advantage of controlling the humidity without adding a new dedicated function. Cost and reliability gains are thus achieved.
In reference to Figures 2 to 5, we will now describe rail transit cars making up other embodiments of the invention. The rail transit cars respectively comprise assemblies 111, 211, 311, 411 shown in Figures 2 to 5, respectively. The rest of the rail transit cars is not shown, for example being identical to the transit car 1 shown in Figure 1 and without the assembly 11.
The assemblies 111, 211, 311, 411 are similar to the assembly 11 shown in Figure 1 and operate similarly. The assemblies 111, 211, 311, 411 are capable of producing the flow of air 33 that is less humid than the ambient air 25.
Consequently, only the differences will be described below. The similar elements are designated using similar references and will not be described again.
In reference to Figure 2, the dehumidifier 19 of the assembly 111 is situated inside the enclosure 15. The dehumidifier 19 comprises a drying unit 135, known in itself, to dry an inner flow of air 137, and a heating member 139, also known in itself, to produce a hot flow of air 141 from an outer flow of air 143.
The outer flow of air 143 comes from the ambient air 25.
The drying unit 135 comprises a moisture absorbing material 145, for example alumina or silica gel, on which the inner flow of air 137 to be dried is intended to pass. The drying unit 135 also comprises means for causing the flow of hot air 141 to pass over the material 145 and collect a residual flow of air 147 charged with water and intended to be evacuated outside the enclosure 15.
The drying unit 135 and the heating unit 139 are situated inside the enclosure 15.
According to another particular embodiment (not shown), the drying unit 135 and heating unit 139 are situated outside the enclosure 15.
The operation of the dehumidifier 19 of the assembly 111 will now be described.
In a production step, the inner flow of air 137 to be dried passes over the material 145. Part of the water contained in the inner flow of air 137 is retained in the material 145. The residual flow of air 33 is collected at the outlet of the drying unit 135.
In a regenerating step, the heating member 139 heats the outer flow of air 143 to obtain the hot flow of air 141. The hot flow of air 141 passes over the material 145 and becomes charged with water. The material 145 is regenerated, in that the water that it has retained is carried away. The residual flow of air 147 is collected at the outlet and evacuated outside the enclosure 15. The flow of air 147 returns to the ambient air 25.
In a manner known in itself, the production and regeneration steps are performed alternately on all of the material 145.
Alternatively, the material 145 is divided into sectors (not shown), and the production and regenerating steps are carried out simultaneously on different sectors from among the sectors of the material 145, each different sector being cyclically subject to the production step, then the regenerating step. Alternatively, cycles with more complex steps, known in themselves, are carried out.
Since the flow of air 33 is substantially equivalent in flow rate to the inner flow of air 137, the enclosure 15 breathes through the passage 23 naturally. "Breathing" refers to the fact the inner air can escape through the passage 23, or the ambient air 25 can enter the enclosure 15 through the passage 23, in particular based on the temperature variations experienced by the inner air.
The use of the dehumidifier as described in the assembly 111 has the advantage of controlling the humidity with high quality and ensuring very quick regulation when the raft is started up.
In reference to Figure 3, the dehumidifier 19 of the assembly 211 differs from the dehumidifier 19 shown in Figure 2 only in that the heating member 139 is configured to heat a second inner flow of their 249 in order to produce the hot flow of air 141.
The operation of the dehumidifier 19 of the assembly 211 differs from that of the dehumidifier 19 of the assembly 111 in that it is the inner flow of air 249 that is heated to pass over the material 145 during the regenerating step, and not an outer flow of air coming from the ambient air 25.
During the regenerating step, the dehumidifier 19 consumes inner air. Consequently, a flow of ambient air flow 251 enters the enclosure 15 through the passage 23 to offset the evacuation of the flow of air 147.
The use of the dehumidifier as described in the assembly 211 has the advantage of limiting the exchange orifices with the ambient air 25.
In reference to Figure 4, the dehumidifier 19 of the assembly 311 differs from the dehumidifier 19 of Figure 3 in that it comprises a water condenser 353 for withdrawing water from the inner flow of air 137 and producing the flow of air 33. The dehumidifier 19 of the assembly 311 does not include heating member similar to the member 139.
The condenser 353 is for example a refrigerating machine capable of cooling the inner flow of air 137 to a temperature below the ambient temperature, advantageously 10°C.
The condenser 353 produces a flow of liquid water 355 evacuated outside the enclosure 15.
The enclosure 15 of the assembly 311 breathes substantially like the enclosure 15 of the assembly 111.
The use of a dehumidifier as described in the assembly 311 has the advantage of limiting the exchange orifices with the ambient air 25. It also allows cooling of the inside of the enclosure 15, which can offset the heating generated by the electrical apparatuses 17.
In reference to Figure 5, the dehumidifier 19 of the assembly 411 differs from the dehumidifier 19 of the assembly 211 shown in Figure 3 in that the driving unit 135 includes a cartridge 453 for withdrawing water from the inner flow of air 137 and producing the flow of air 33. The dehumidifier 19 of the assembly 411 does not include a heating member similar to the member 139, since the cartridge 453 is not regenerated, but replaced.
The cartridge 453 contains a moisture absorbing material 455 to trap water contained in the inner flow of air 137 and produce the flow of air 33.
The cartridge 453 is periodically replaced by a similar cartridge, for example if water saturation of the material 455 is observed. Water saturation results in a loss of efficiency of the dehumidifier 19.
"Flow of air" in this document refers either to a flow of air channeled by forced convection (case of the flow of air 33 in the assemblies 11, 111, 211, 311), or a flow of air that is created by molecular diffusion or natural convection (case of the assembly 411). In the assembly 411, water contained in the inner air is trapped in the material 455, which creates the less humid flow of air 33. The inner flow next becomes homogenous in terms of humidity level in the enclosure 15 owing to the movements of the inner air.
The material 455 is for example alumina or silica gel.
The enclosure 15 of the assembly 411 breathes substantially like the enclosure 15 of the assemblies 111 and 311.
The use of a dehumidifier as described in the assembly 411 has the advantage of limiting the exchange orifices with the ambient air 25.

claim:
1.- An electrically driven vehicle (1), in particular a rail vehicle, including at least one electrical device (9) and an assembly (11; 111; 211; 311; 411), the assembly (11; 111; 211; 311; 411) comprising:
- a plurality of high-voltage electrical apparatuses (17) for powering or controlling the electrical device (9), and
- an enclosure (15) that is not hermetic with respect to the ambient air (25), the enclosure (15) containing the electrical apparatuses (17) and defining an inner volume (21) filled with inner air,
thevehicle being characterized in that the assembly (11; 111; 211; 311; 411) further includes a dehumidifying device (19) capable of producing a flow of air (33) that is less humid than the ambient air (25), the flow of air (33) emerging in the inner volume (21).

2.- The vehicle (1) according to claim 1, characterized in that the dehumidifying device (19) comprises a compressed air unit (20) for producing compressed and dried air (27) from the ambient air (25), the compressed air unit (20) being designed to supply the vehicle (1) with compressed and dried air, the dehumidifier device (19) comprising at least one channel (31) to withdraw at least a fraction of the compressed and dried air (27) and obtain the flow of air (33) that is less humid than the ambient air (25).

3.- The vehicle (1) according to claim 1, characterized in that the dehumidifying device (19) comprises a drying unit (135), the produced flow of air (33) resulting from the drying of a first inner flow of air (137) inside the drying unit (135).

4.- The vehicle (1) according to claim 3, characterized in that the drying unit (135) comprises at least one material (145; 455) absorbing moisture to dry the first inner flow of air (137).

5.- The vehicle (1) according to claim 4, characterized in that the dehumidifying device (19) comprises a heating member (139) for producing a flow of hot air (141) designed to pass through the moisture absorbing material (145) so as to regenerate the moisture absorbing material (145), the flow of hot air (141) being evacuated outside the enclosure (15) after it passes through the moisture absorbing material (145).
6.- The vehicle (1) according to claim 5, characterized in that the heating member (139) is configured to heat a flow of ambient air (143), the flow of hot air (141) being obtained by heating the flow of ambient air (143).

7.- The vehicle (1) according to claim 5, characterized in that the heating member (139) is configured to heat a second inner flow of air (249), the flow of hot air (141) being obtained by heating the second inner flow of air (249).

8.- The vehicle (1) according to claim 4, characterized in that the drying unit (135) comprises at least one cartridge (453) that can be removed from the drying unit (135), the cartridge (453) containing at least one fraction of the moisture absorbing material (455), the cartridge (453) being designed to be replaced periodically by another cartridge similar to said cartridge (453).

9.- The vehicle (1) according to claim 3, characterized in that the drying unit (135) comprises a condenser (353) to produce the less humid flow of air (33) by cooling of the first inner flow of air (137) and by condensing water, the removed water (355) being evacuated outside the enclosure (15).

10.- A method for powering or controlling at least one electrical device (9) of an electrically driven vehicle (1), in particular a rail vehicle, comprising at least one step for powering or controlling the electrical device (9) using a plurality of high-voltage electrical apparatuses (17) situated in an enclosure (15) of the vehicle (1), the enclosure (15) not being hermetic with respect to the ambient air (25) and defining an inner volume (21) filled with air,
the method being characterized in that it further includes a dehumidifying step capable of producing a flow of air (33) that is less humid than the ambient air (25), said flow of air (33) emerging in the inner volume (21).