Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B61—RAILWAYS
  • B61C—LOCOMOTIVES; MOTOR RAILCARS
  • B61C17/00—Arrangement or disposition of parts; Details or accessories not otherwise provided for; Use of control gear and control systems
  • B61C17/04—Arrangement or disposition of driving cabins, footplates or engine rooms; Ventilation thereof

Definitions

• aspects of the present disclosure relate to a railroad vehicle having an electric power conversion device with a cooling circuit located at a roof level of a railroad vehicle, and for a method of cooling an electric power conversion device located at a roof level of a railroad vehicle.
• traction transformers in railroad vehicles typically require a pump to ensure forced liquid cooling of the windings, and a cooling system composed of a heat exchanger and fans to ensure forced air cooling of the cooling liquid, typically oil.
• traction transformers are specified with much higher power densities than other types of transformers, since they are embedded in trains, with very limited available volume and weight restrictions.
• smaller core sections and wire sections are used in order to downsize both core and windings.
• Reduced core section results in increased number of turns and thus wire length, which in combination with higher current density of the turns results in significantly higher transformer losses.
• a typical efficiency of a traction transformer is 93-95%.
• a significant amount of heat has to be dissipated from such transformers, which at the same time have a very compact form factor.
• traction transformers cannot be cooled naturally, which is why an active cooling including a cooling liquid, a pump, heat exchangers and fans are typically necessary to enable efficient cooling.
• the active mechanical parts of such a cooling system are naturally also more prone to failure than a transformer.
• Similar problems arise with other electric power conversion devices employed in railroad vehicles, such as, e.g., semiconductor-based switching units for the electric motors, which also produce a significant amount of thermal energy whilst having a compact form factor, and thus also require active cooling.
• a railroad vehicle comprises an electric power conversion device, a cooling circuit comprising a fluid, which is thermally connected to the electric power-conversion device and comprises at least one heat-exchanger for dissipating thermal energy from the electric power-conversion device to surrounding air, wherein at least one side wall of the railroad vehicle comprises at least one opening, and wherein the at least one heat exchanger is arranged to be cooled by an air flow through the at least one opening caused by a movement of the railroad vehicle, and wherein the at least one heat exchanger and the at least one opening are located at a roof level of the railroad vehicle.
• a method for cooling an electric power conversion device located at a roof level of a railroad vehicle includes guiding an air flow from a side of the railroad vehicle through an at least one opening in at least one side wall of the railroad vehicle; guiding the air flow to a heat exchanger being part of a cooling circuit comprising a fluid, the cooling circuit being connected to the electric power conversion device; dissipating thermal energy from the electric power conversion device via the at least one heat exchanger to the air flow; guiding the air flow out through an at least one opening.
• FIG. 1 shows a cross-sectional view of the roof section of a railroad vehicle according to embodiments
• Fig. 2 shows a cross-sectional view of the roof section of a railroad vehicle according to further embodiments
• Fig. 3 shows a perspective view on a roof section of a railroad vehicle according to further embodiments
• Fig. 4 shows a cross-sectional view of the roof section of a railroad vehicle according to embodiments
• Fig. 5 shows a cross-sectional view of the roof section of a railroad vehicle according to further embodiments
• Fig. 6A shows a cross-sectional view of the roof section of a railroad vehicle according to yet further embodiments;
• Fig. 6B shows a cross-sectional view of the roof section of a railroad vehicle according to still further embodiments
• Fig. 7 shows a cross-sectional view of the roof section of a railroad vehicle according to further embodiments.
• Fig. 8 shows a side view on a railroad vehicle according to embodiments.
• fluid is intended to be both representative for gases and liquids.
• a fluid may have two different phase states, namely liquid and gaseous, and wherein during the cooling process, the fluid changes from one to the other and reverse.
• any aspect or embodiment described in this document can be combined with any other aspect or embodiment, as long as the combinations achieved are technically feasible, or unless the contrary is mentioned.
• the at least one side wall has a first opening as an inlet for the air flow and a second opening as an outlet for the air flow, and the heat exchanger is located between the first opening and the second opening; or the at least one opening serves both as an inlet opening and as an outlet opening for the air flow; or an inlet opening is located in a first side wall, and an outlet opening is located in a second side wall opposite to the first side wall, and wherein the inlet opening and the outlet opening are arranged at different distances with respect to an end portion of the railroad vehicle; or at least one inlet opening is located in a first side wall, and optionally at least one inlet opening is located in a second side wall opposite to the first side wall, and wherein at least one outlet opening is located in a region upwards from the electric power conversion device, preferably in the form that the electric power conversion device mounted in the roof area has no covering wall above it.
• the electric power conversion device is a fluid-cooled transformer, a fluid-cooled motor, a fluid-cooled semiconductor switching device, or any combination of the former devices.
• the fluid is at least one of: an Alkane, a Halocarbon, a Fluoroketone, a dielectric fluid oil such as in particular natural esters and/or synthetic esters or silicone oil or mineral oil, water, and fluids comprising water and additives.
• the cooling circuit comprises tubes connecting the electric power- conversion device with the heat exchanger, and wherein optionally, the cooling circuit comprises: an evaporator portion, and a condenser portion located in the heat-exchanger, and is configured for two-phase-cooling.
• the heat exchanger comprises cooling fins and/or tubes, and wherein optionally, at least a part of the heat exchanger is a part of, or mounted to, a housing of the electric power conversion device.
• the at least one inlet opening and/or the at least one outlet opening are arranged on substantially the same height level of the railroad vehicle.
• the air flow is guided at least on a part of its path in the railroad vehicle by air guiding elements configured to confine and/ or direct the air flow.
• At least a part of at least one opening may be actively opened and closed by at least one movable element.
• a method of cooling an electric power conversion device includes that at least one side wall has a first opening as an inlet opening for the air flow, and a second opening as an outlet for the air flow, and wherein the heat exchanger is located between the first opening and the second opening; or that at least one opening serves both as an inlet opening and as an outlet opening for the air flow; or that an inlet opening is located in a first side wall, and an outlet opening is located in a second side wall opposite to the first side wall, and wherein the inlet opening and the outlet opening are arranged at different distances with respect to an end portion of the railroad vehicle, or that at least one inlet opening is located in a first side wall, and optionally at least one inlet opening is located in a second side wall opposite to the first side wall, and wherein at least one outlet opening is located in a region upwards from the electric power conversion device, preferably in the form that the electric power conversion device mounted in the roof area has no covering wall above it.
• the method further includes actively opening or closing at least a part of the at least one opening with a movable element.
• the opening or closing is carried out in dependency of at least one of: the direction of movement of the railroad vehicle, and the travelling speed of the railroad vehicle.
• the railroad vehicle may further comprise a network interface for connecting it to a data network in the railroad vehicle and/or in particular to a global data network.
• the data network may be a TCP/IP network such as Internet.
• the railroad vehicle, and in particular an included control unit may be operatively connected to the network interface for carrying out commands received from the data networks in the train and/or the global data network.
• the commands may include a control command for controlling the cooling system as described in aspects, and to carry out a task such as changing parameters of the cooling system, for example by moving the control element controlling the air flow(s).
• the device/controller is adapted for carrying out the task in response to the control command.
• the commands may include a data request.
• the apparatus may be adapted for sending measurement information (e.g., a measurement report including temperature(s) measured by at least one sensor in the electric power conversion device or in/at the cooling circuit) to the network interface, and the network interface is then adapted for sending the measurement information over the network in the train and/or the global network.
• the measurement information is preferably sent over the network as digital information.
• the commands may include an update command including update data.
• the control unit is adapted for initiating an update in response to the update command and using the update data.
• the control unit and/or the railroad vehicle may be partially or fully accessible over the data network.
• the data network may be an Ethernet network using TCP/IP such as LAN, WAN or Internet.
• the data network may also include a cellular network such as GSM, GPRS, 3G, 4G/LTE, or 5G.
• the data network may comprise distributed storage units such as Cloud. Depending on the application, the Cloud can be in form of public, private, hybrid or community Cloud.
• Information which may be sent/received over the train data network or the global data network may include data, particularly measurement and sensor data, about the cooling circuit, the electric power conversion device, optionally the movable element, and other railroad vehicle status information.
• Control commands from the global data network or the train data network may be sent to the control unit in order to change parameters of the cooling circuit, e.g., by moving the movable elements to control the air flow, typically in dependency of parameters like temperature(s), power throughput in the electric power conversion device, outside temperature, direction of movement of the railroad vehicle, and speed of movement of the railroad vehicle.
• an opening is, independently from the movement direction of the vehicle, always an inlet opening and at the same time an outlet opening, while other openings may have a differing function (inlet or outlet), e.g., depending on the movement direction.
• Openings are generally described to have reference signs 40, 41, 45, 46, 47, 48, and their respective role in the specific embodiment is described with terms like “first opening”, “second opening”, “inlet opening”, and “outlet opening”, while these terms shall not be regarded as a limitiation due to the potentially varying functions and roles of the individual openings, see above.
• the heat exchangers are typically configured so that a cooling air stream passes at least partially, or entirely, through the body of the heat exchanger.
• Fig. 1 shows a top view on a roof section/portion of a railroad vehicle 1 according to embodiments, with elongation from left to right.
• the vehicle has an electric power conversion device 10, which in the embodiment is a transformer.
• a cooling circuit 15 (encircled by dashed line) for the electric power conversion device 10 comprises a fluid.
• the cooling circuit is thermally connected to the electric power-conversion device 10 and comprises two heat exchangers 20, 21 for dissipating thermal energy from the electric power-conversion device to surrounding air.
• tubes 16 are provided to fluidly connect the electric power conversion device 10 with the heat exchangers 20, 21. Also in other embodiments described herein, tubes 16 are employed, in particular if the heat exchangers 20, 21 are not directly adjoined to the electric power conversion device 10.
• openings 40, 41 are provided in opposing side walls 30, 31 of the railroad vehicle 1.
• a heat exchanger 20, 21 is arranged to be cooled by an air flow through the respective opening 40, 41.
• the air flow is caused by a movement of the railroad vehicle 1 during its operation.
• each opening 40, 41 serves as an inlet for the air stream and also as an outlet.
• the heat exchanger 20, 21 is arranged such that the air flow passing the opening 40, 41 cools the heat exchanger 20, 21.
• the heat exchangers 20, 21 and the openings 40, 41 are located at a roof level of the railroad vehicle 1. Via the heat exchangers 20, 21, thermal energy from the electric power-conversion device 10 is dissipated to the air flow, and thus to air surrounding the vehicle. Thus, the heat exchangers 20, 21 are cooled by the air flow.
• Certain classes of railroad vehicles require that the electric power conversion device 10 and heat exchangers 20, 21 are mounted at the roof level of the railroad vehicle 1. Having the heat exchangers 20, 21 located at a roof level of the railroad vehicle 1 allows for several improvements to cooling performance as compared to having the heat exchangers 20, 21 located at an underfloor level of the railroad vehicle 1. For example, heat exchangers 20, 21 located at an underfloor level may be damaged by debris which is prevalent at the underfloor level, requiring additional protection to prevent such damage. Further, the airflow available to heat exchangers 20, 21 at an underfloor level is typically turbulent with a high boundary layer thickness caused by other components at the underfloor level, such as the bogies of the railroad vehicle, leading to reduced cooling performance of the heat exchangers.
• railroad vehicles having the heat exchangers 20, 21 located at a roof level have several advantages compared to having the heat exchangers 20, 21 located at an underfloor level.
• side skirts already exist at a roof level along the length of the vehicle for aerodynamic and aesthetic reasons, while such side skirts are much less frequent at an underfloor level.
• roof-level side skirts along the length of the vehicle provide a homogenous flow with lower turbulence and a low thickness boundary layer, providing conditions for improved cooling of heat exchangers 20, 21 located at a roof level of the railroad vehicle.
• improved cooling performance allows for smaller openings to be used for cooling heat exchangers 20, 21, thus reducing aerodynamic drag of the railroad vehicle.
• the electric power conversion device 10 may be a fluid-cooled transformer like in Fig. 1 , a fluid-cooled motor, a fluid-cooled semiconductor switching device, or any combination of the former devices.
• the fluid of the cooling circuit 15 may, as non-limiting examples, be an Alkane, a Halocarbon, a Fluoroketone, a dielectric fluid oil such as in particular natural esters and/or synthetic esters or silicone oil or mineral oil.
• the fluid may be water, deionized water, or a fluid comprising water and additional components or additives, such as an anti-freezing agent, for example glycol.
• the at least one heat exchanger 20, 21 may comprise cooling fins and/or tubes (not shown).
• at least a part of the heat exchanger 20, 21 may be mounted to a housing 11 of the electric power conversion device 10, or the heat exchanger may be an integral part of the housing 11.
• the housing 11 itself may serve as the heat exchanger.
• the openings 40, 41, 45, 46, 47, 48 described herein are arranged on substantially the same height level of the railroad vehicle 1 at a roof level/portion A- A, see also Fig. 8.
• a railroad vehicle 1 according to further embodiments is depicted.
• an inlet opening 45 for the air flow is located in a first side wall 30, and an outlet opening 46 is located in a second side wall 31 opposite to the first side wall 30.
• the inlet opening and the outlet opening are arranged at different distances with respect to an end portion of the railroad vehicle 1 , so that an air flow oblique to a longitudinal axis of the vehicle results.
• the air flow is guided at least on a part of its path in the railroad vehicle 1 by air guiding elements 60 configured to confine and/or direct the air flow.
• Fig. 3 shows a railroad vehicle according to further embodiments, wherein in each side wall 30, 31, two openings are provided.
• one side wall 30 has a first opening 45 as an inlet for the air flow and a second opening 46 as an outlet for the air flow (which may be reversed when the vehicle changes direction of movement), wherein the heat exchanger 20 is located between the first opening 45 and the second opening 46, and on the other side it is located between inlet opening 47 and outlet opening 48.
• Fig. 4 shows an embodiment where a transformer 10 and the heat exchanger 20 are provided side by side arranged in a longitudinal direction of the vehicle 1. i each side wall 30, 31, two openings 45, 46, 47, 48 are provided.
• each combined with an air guiding member 60, confined air channels 50, 51, 52, 53 are employed leading from the openings towards an inward of the railroad vehicle 1 , which may also be combined with other embodiments.
• FIG. 5A an embodiment similar to the one of Fig. 4A is shown, whereby two heat exchangers 20, 21 are provided for one power conversion device 10. Depending on the direction of movement of the vehicle, either of the two heat exchangers will be subjected to a stronger air flow than the second heat exchanger.
• FIG. 6 A an embodiment is shown, where two openings 45, 46 in the same side wall 30 serve as inlet and outlet opening, respectively. Thereby, the heat exchanger 20 is positioned to be in the air flow between both openings 45, 46.
• the electric power conversion device 10, here exemplarily shown as a transformer, is not in the main air stream in this case.
• the cooling circuit comprises at least one heat exchanger 20 for dissipating thermal energy from the electric power-conversion device 10 to the air of the air stream between openings 45, 46.
• the openings 45, 46 are both provided in one side wall 30 of the railroad vehicle 1.
• the air flow is caused by a movement of the railroad vehicle 1 during its operation.
• the openings 45, 46 change their role as inlet for the air stream and as outlet for the air stream.
• thermal energy from the electric power conversion device 10 is dissipated to the air outside of the railroad vehicle 1 via the fluid in the cooling circuit and the heat exchanger 20.
• Fig. 6B shows an embodiment similar to that of Fig. 6A, but with additional openings 47, 48 in the opposite side wall 31, providing an additional air flow for the transformer 10.
• the transformer may be equipped with, e.g., cooling fins or tubes on its housing 11 to improve heat transfer to the air flow.
• Fig. 7 an embodiment based on that of Fig. 6A is shown, but with two power conversion devices 10, 10b, for example a transformer and a semiconductor switching unit. These are connected via tubes (not shown) to two heat exchangers 20, 21 located in the air flow between openings 45, 46. It is understood that also other numbers and combinations of power conversion devices 10 may be combined with other numbers of heat exchangers 20, 21. Also, one air flow/air stream as in Fig. 7, or more air streams as in Fig 6B may be employed according to embodiments. In embodiments described herein, at least a part of the at least one opening 40, 41, 45, 46, 47, 48 may actively be opened or closed with at least one movable element 65a, 65b, as exemplarily shown in Fig. 7.
• At least a part of at least one of the openings 40, 41, 45, 46, 47, 48 may be actively opened and closed by at least one movable element 65a, 65b.
• the opening or closing is typically controlled by a control unit, and carried out in dependency of at least one of: the direction of movement of the railroad vehicle 1, and the travelling speed of the railroad vehicle 1.
• Fig. 8 shows a railroad vehicle 1 according to embodiments described herein, exemplarily and non-limiting with two openings 45, 46 at a roof section, exemplarily indicated by line A- A showing the roof level.
• all embodiments described herein may be realized at a roof level A-A.
• the openings may also be provided at any height level between the roof level and the underfloor level B-B, and the various components like heat exchanger and electric power conversion device may also be arranged at different height levels with respect to each other.

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• Engineering & Computer Science (AREA)
• Automation & Control Theory (AREA)
• Transportation (AREA)
• Mechanical Engineering (AREA)
• Electric Propulsion And Braking For Vehicles (AREA)
• Inverter Devices (AREA)

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• 2018
  • 2018-10-30 WO PCT/EP2018/079685 patent/WO2019086441A1/en unknown
  • 2018-10-30 JP JP2020524203A patent/JP2021501090A/ja active Pending
  • 2018-10-30 EP EP18795596.8A patent/EP3703992A1/en active Pending
  • 2018-10-30 CN CN201880070837.XA patent/CN111278709B/zh active Active

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