Switchover device for traction drive

Abstract

The invention relates to a switchover device (1) for a traction system of a rail vehicle (19), comprising - a first switching module (2) having power inputs (6) for connection to a power converter (15), having power outputs (7, 7a, 7b) for connecting to at least one traction motor (8a, 8b) and having switching elements for carrying out a group switchover, depending on a predefined operating range of the traction motor (8a, 8b), between the power inputs (6) and the power outputs (7, 7a, 7b), - a communication module for transmitting traction motor parameters {Ln, Rn, p} to the power converter (15) depending on the predefined operating range.

Description

[0001] Switching device for traction drive

[0002] The invention relates to a switching device for at least one traction drive of a rail vehicle.

[0003] The invention further relates to a traction system for a rail vehicle with at least one traction drive, comprising at least one power converter, at least one switching device and at least one traction motor.

[0004] The subject of the invention is also a rail vehicle with working units and with a speed-adjustable traction drive which contains at least one power converter, provided for controlling traction motors which are designed to drive axles of the rail vehicle, wherein the speed range used of the traction motors is characterized by a first operating range in which the rail vehicle is provided to work on a rail track with its working units, and a second operating range in which the rail vehicle is provided to travel on the rail track without it being worked on by the working units.

[0005] Specialised rail vehicles are used for the construction and maintenance of rail tracks in the railway infrastructure in countries and regions. These vehicles, for example, produce or renew the ballast layer of the track superstructure, lay the sleepers and rails on this ballast layer, assemble and align them and correct any faulty track position, measure an existing track position, lay, assemble and renew the modules of a slab track or construct or renew an overhead line system.These specialised rail vehicles are referred to as track construction or track maintenance machines and are characterised by at least one working unit such as a tamping unit, a lifting and straightening unit, a ballast plough, at least one mechanical or optical reference axis, a track position measuring device, one or more units for producing or renewing the superstructure material layers, at least one welding and / or grinding unit for the rails of the railway track and / or a working unit for the construction and maintenance of the overhead line.

[0006] Two or more of these specialised rail vehicles can also be coupled to form rail vehicle units and, through the arrangement of a subset of the above-mentioned work units, provide a specific range of functions for the construction or maintenance of a rail track.

[0007] The operation of rail vehicles for track construction includes, according to the state of the art, two different speed ranges, which are suitable for

[0008] ( 1 ) Transfer journeys or surveying journeys typically range from 20 km / h to over 100 km / h and which

[0009] ( 2 ) Processing of the rail track by means of the working units is typically between 0.2 km / h and 3 km / h.

[0010] The aforementioned rail vehicles are either equipped with their own traction drives or are moved in a train of rail vehicles equipped with traction drives. In addition to traction drives that operate according to the principle of thermodynamic internal combustion engines, i.e., they convert the chemical binding energy of a fuel through exothermic chemical reactions into a rotary or linear mechanical motion sufficient for the traction of the rail vehicle, electrodynamic traction drives are also increasingly being used due to technical, economic, social, and ecological considerations.

[0011] According to the state of the art, in order to enable continuous operation in the two operating points or operating ranges of the speed of the rail vehicle specified above, the control of the electric traction motors of these traction drives is operated at frequencies between less than 2 Hz and several hundred Hertz at high motor currents, whereby the efficiency of the traction drive is reduced due to the wide spread of these operating points or operating ranges.

[0012] The effort required to control and regulate the traction drive is also high in this case.

[0013] For example, the controllability and adjustability of common variable-speed traction drives, which comprise a combination of power converters and traction motors, is impaired at very low control frequencies due to inherent limitations of the modulation process.

[0014] If the speed range is extended or spread without switching being provided, high values ​​for the input currents of the machine are necessary due to necessary compromises in the design and construction in order to achieve the required torques and tensile forces.

[0015] A possible alternative is to place a mechanical gearbox after the traction motor to switch between the two speed ranges.

[0016] From AT 521 386 A1 an interface device between energy converters for energy supply, energy storage devices and other energy converters such as drive units for a track construction machine is also known.

[0017] The invention is based on the object of providing an improvement over the prior art for a switching device of the type mentioned above.

[0018] A further object of the invention is to provide a traction system which is designed for operation with the switching device according to the invention in a traction drive which is improved compared to the prior art.

[0019] Finally, it is also an object of the invention to provide a rail vehicle with working units with the speed-adjustable traction drive which is improved compared to the prior art.

[0020] According to the invention, these objects are achieved by the switching device of claim 1, the traction system of claim 7 and the rail vehicle of claim 9.

[0021] Dependent claims specify advantageous embodiments of the invention. The invention relates to a switching device for a traction system of a rail vehicle, comprising a first switching module with power inputs for connection to a power converter, with power outputs for connection to at least one traction motor, and with switching elements for carrying out a group switchover between the power inputs and the power outputs dependent on a predetermined operating range of the traction motor, as well as a communication module for transmitting traction motor parameters to the power converter depending on the predetermined operating range.

[0022] A preferred variant of the switching device according to the invention further comprises a control module which is provided to trigger and / or monitor the group switching dependent on the operating range and / or to transmit the traction motor parameters dependent on the operating range to the power converter by means of the communication module.

[0023] Traction motor parameters are, for example, the values ​​of the traction motor impedances Z controlled by the power converter n , which can be approximated as a series connection of an inductance L n with resistance value X depending on the alternating current frequency n =2nf - L n , which is also called reactance, and a frequency-independent ohmic resistance value R n can be accepted .

[0024] Other important parameters include the number of poles 2p and / or the number of pole pairs p of the traction motor. In another advantageous variant of the switching device, a second switching module is provided for a safe torque off shutdown of the traction drive and / or for galvanically isolating the power inputs from the first switching module and / or from the power outputs.

[0025] This additional safety-relevant "safe torque off" (STO) according to IEC 61800-5-2: 2016 RLV provides a redundant shutdown path in addition to the power converter by separating the power inputs from the power outputs using a main switching element, thereby achieving a higher level of safety.

[0026] For example, with this STO shutdown, performance level d or e according to category 3 or 4 of EN ISO 13849-1 is achieved and other railway-specific safety requirements such as "dangerous event due to single fault is not acceptable" are met.

[0027] The requirement "prevention of unwanted movement" in EN 14033-2:2017, section 5.15, Table 1 is also met, as are the safety requirements for the braking system in paragraph 4.2.4.2.2, Table 3 of the Technical Specification for Interoperability TS I relating to the subsystem "Rolling stock - Locomotives and Passenger Rolling Stock" of the railway system in the European Union pursuant to Regulation (EU) No. 1302 / 2014.

[0028] An advantageous variant provides for an overvoltage module to be installed as part of the switching device to reduce or prevent overvoltages between the traction motors and the power converter. Overvoltages can occur, for example, during switching operations that separate the winding phases of the traction motors from the phases of the supply lines.

[0029] An example of such a switching process is, in particular, the group switching between a first and a second operating range of the rail vehicle.

[0030] In a favorable variant of the switching device, the first switching module is provided to carry out a group switching between the phases of the power inputs and the winding phase groups of the traction motor, which are connected to the power outputs, in such a way that the winding phase groups form a double star configuration with each other and with the power inputs for a first operating range and a star configuration for a second operating range.

[0031] The group switching of the winding phase groups between the star configuration and the double star configuration leads to a change in the traction motor parameters Z n or L n and R n .

[0032] Different configurations of the winding phase groups can also correspond to different numbers of poles 2p or numbers of pole pairs p of the traction motor.

[0033] In the general case, switching the winding phase groups can lead to an increase or decrease in the number of pole pairs in the ratio l : n, where n is a natural number.

[0034] Increasing the number of pole pairs p by a factor of n has a

[0035] Reduction of speed n M of the traction motor by the same factor n at constant AC frequency f in the phases of the three-phase supply, since the ratio between speed n M and the number of pole pairs p is inversely proportional.

[0036] In a variant of the above group switching between double star and star, the ratio between the number of pole pairs is 2 : 1 and consequently the ratio between the speed n Mf l of the traction motor in the first configuration and that Mf 2 in the second configuration 1 : 2 under the condition of constant alternating current frequency or three-phase current frequency f .

[0037] If at a certain speed n M of the traction motor is switched between the first and the second configuration, this three-phase frequency fj must be adjusted according to the ratio of the number of pole pairs p of these two configurations in order to avoid jumps in the speed n M and / or to avoid high loads on the traction motor.

[0038] In an alternative embodiment, the switching device is configured to switch between a delta configuration of the winding phase groups of the traction motor and a double star configuration.

[0039] These two alternative configurations of the winding phase groups result in a ratio of the number of pole pairs p of 2 : 1, which corresponds to a speed ratio n Mf l : n Mf 2of 1 : 2 under the condition of constant three-phase frequency f . In an advantageous embodiment, the switching device is provided to connect a power converter to at least two traction motors of a bogie of the rail vehicle.

[0040] Due to this type of control, the number of switching devices and power converters required is reduced.

[0041] This results in a smaller space requirement for the traction drive and the traction system and a significant reduction in manufacturing costs.

[0042] The drive of both axles of a bogie enables the rail vehicle to achieve higher drive forces with optimal utilization of given axle loads.

[0043] In an advantageous embodiment of the traction system for a rail vehicle with a power converter, the power converter is connected to a switching device in one of the variants described above and comprises a control module which is provided to trigger and / or monitor the group switching dependent on the operating range and / or to receive the traction motor parameters dependent on the operating range from the switching device by means of a communication module.

[0044] The converter must at all times be aware of the current configuration of the winding phase groups of the traction drive, which is determined by the traction parameters { L n , R n , p} in order to provide a three-phase system of suitable amplitude Ü and frequency f for the at least one traction motor switched on by means of the switching device.

[0045] In an alternative embodiment, the control module of the power converter or of a higher-level control unit such as the machine control is provided, instead of that of the switching device, to trigger and / or monitor the group switching dependent on the operating range.

[0046] Preferably, in one embodiment of the traction system, a communication connection is set up between the communication modules of the power converter and the switching device and provided for a transmission of data and signals which is carried out in analog and / or digital, in particular binary coded form.

[0047] Such data are in particular the traction motor parameters { L n , R n , p} •

[0048] A preferred embodiment of the subject matter of the invention comprises a rail vehicle with working units and with a speed-adjustable traction drive which contains at least one power converter, provided for controlling traction motors which are designed to drive axles of the rail vehicle, wherein the used speed range of the traction motors is characterized by a first operating range in which the rail vehicle is provided to work on a rail track with its working units, and a second operating range in which the rail vehicle is provided to travel on the rail track without this being worked on by the working units, wherein a switching device according to the invention is arranged between the power converter and at least one traction motor.

[0049] The second operating area can be in a further

[0050] In this embodiment, the rail track may be measured using specialised measuring devices arranged on the rail vehicle.

[0051] In an alternative variant of the rail vehicle, all power converters of the traction drives are arranged in one housing.

[0052] Such an arrangement in a housing makes it possible, for example, to use devices approved for railway current for controlling the traction motors by means of the switching devices according to the invention.

[0053] In a favorable alternative embodiment, the traction drives are arranged partially or entirely in the vicinity of the drive axles of the rail vehicle.

[0054] This design enables the use of industrial power converters or industrial inverters with reduced output currents compared to traction power converters.

[0055] These converters may require a separate approval for use in a rail vehicle.

[0056] In a preferred embodiment, the traction drives located near the drive axles are designed to be supplied by a direct current line located in the rail vehicle. Such a direct current supply can be found, for example, in AT 521 386 A1.

[0057] The connection of the converter output, which provides a variable frequency three-phase system, with the power inputs of the switching device by means of a connecting cable, the length of which is only a fraction of the length of the rail vehicle or the length of the rail vehicle combination, is also advantageous in terms of increasing the electromagnetic compatibility EMC due to a reduction of disturbing electromagnetic radiation.

[0058] The invention is explained below by way of example with reference to the accompanying figures. They show schematically:

[0059] Fig. 1 An embodiment of the inventive

[0060] Switching device with its functional modules,

[0061] Fig. 2a A first embodiment of the switching device according to Figure 1 as a circuit diagram with two controlled traction motors,

[0062] Fig. 2b A further embodiment of the switching device according to Figure 1 as a circuit diagram,

[0063] Fig. 3a A first arrangement of a total of six groups of winding phases of a traction motor as a double star and their control with three phases of a three-phase system, Fig. 3b A second arrangement of the winding phase groups from Figure 3a as a star connection,

[0064] Fig . 3c A third arrangement of the winding phase groups from Figure 3a as a double star with a common star point,

[0065] Fig. 4a Course of voltage, current and torque / power of a traction motor over the speed v of a rail vehicle, which is controlled in the first switching position of the switching device,

[0066] Fig. 4b Course of voltage, current and torque / power of a traction motor over the speed v of a rail vehicle, which is controlled in the second switching position of the switching device,

[0067] Fig. 4c Joint representation of the characteristic curves from Figures 4a and 4b,

[0068] Fig. 5 Schematic representation of a traction system consisting of three traction drives, each consisting of a power converter, an associated switching device and two controlled traction motors with a common optional control module,

[0069] Fig. 6 Rail vehicle with the inventive

[0070] Traction system for driving four bogies with two axles each, Fig. 7 a An alternative view of the winding strand groups arranged in a double star with two separate star points according to Figure 3a,

[0071] Fig . 7b The alternative view analogous to Figure 7a of the winding phase groups arranged in star connection according to Figure 3b,

[0072] Fig . 7c The alternative view analogous to Figure 7a of the winding phase groups arranged in the double star with a common star point according to Figure 3c .

[0073] In Figure 1, the switching device 1 according to the invention, which connects power inputs 6 to power outputs 7a, 7b, is shown schematically with its functional modules 2, 3, 4 and 5.

[0074] Thus, an overvoltage module 5 is provided as overvoltage protection for the power inputs 6 in order to reduce or avoid overvoltages which can occur in particular when switching on, off and changing over the winding phase groups 11a, 11b, 11c, 11d, 11e, 11f of the winding system of at least one traction motor 8a, 8b.

[0075] A prior art overvoltage module 5 comprises, for example, a Zener diode suitable for the given power range or another electromechanical, electrical, and / or power electronic component suitable for overvoltage protection. This overvoltage module 5 protects the connected devices at the power input 6 from interference caused by high switching voltages.

[0076] It also acts as a limiting factor against such high switching voltages both within the switching device 1 and at the power outputs 7a, 7b.

[0077] The power inputs 6 are connected to the first switching module 2 by means of a second switching module 4 which comprises a main switch, the essential components of which are the switching elements of a group switch.

[0078] The second switching module 4 serves to disconnect the power inputs 6 from the first switching module 2 or to reconnect them to it.

[0079] In order to prevent high switching voltages in the system, a controlled demagnetization of the winding system 11a, 11b, 11c, l ld, I le , llf , in particular of the magnetizable parts, of the at least one traction motor 8a, 8b is advantageously carried out, preferably by means of the power converter 15, before the connections between the winding phase groups 11a, 11b, 11c, l ld, I le , llf are separated.

[0080] The process of disconnecting the power inputs 6 from the first switching module 2 and subsequently reconnecting them is carried out operationally as part of the group switching.

[0081] The first switching module 2 is used to switch between different connection variants between the power inputs 6 and the power outputs 7a, 7b. In particular, switching takes place between a connection variant which connects the winding phase groups 11a, 11b, 11c, 11d, 11e, 11f in two mutually parallel stars to the feeding three-phase system of the power inputs 6, and a second connection variant in which two winding phase groups 11a, 11b, 11c, 11d, 11e, 11f are connected in series for each three-phase phase of the power inputs 6, and the series circuits fed in this way are connected to one another at a star point SRI on their side facing away from the respective three-phase phase U, V, W.

[0082] The first connection variant is known as a double star connection and the second connection variant is known as a star connection.

[0083] In the switching device 1, a control module 3 is further provided to initiate, monitor and complete the switching process and to transmit the respective parameters, which are each assigned to one of the two connection variants, to a power converter 15 via a communication module.

[0084] This power converter 15 generates the three-phase system connected to the power inputs 6 with adjustable alternating current frequency f and likewise adjustable phase voltage Ü .

[0085] Figure 2a shows a first embodiment of the switching device 1 as a circuit diagram, with which two traction motors 8a, 8b are controlled.

[0086] This arrangement is suitable, for example, for use in a bogie 22 of a rail vehicle 19 or rail vehicle combination with two driven axles, as shown by way of example in Figure 6.

[0087] The circuit diagram of Figure 2a shows the power inputs 6 and their connection to the power outputs 7 by means of the first switching module 2 .

[0088] This first switching module 2 has two switching positions which correspond to two different switching configurations of the power outputs 7 with each other and with the power inputs 6.

[0089] The first switching module 2 is an electrically or electromagnetically operated switch which is controlled via a switching input "SHI FT" and, in the embodiment shown, switches a total of eight switching contacts between a first switching position and a second switching position. These switching contacts are connected to the three lines U, V, W of the power inputs 6 as well as to the nine lines U1, V1, W1, U2, V2, W2 and U3, V3, W3 of the power outputs 7.

[0090] For example, the first switching contact is open in the first switching position, whereby the connection between U and U3 is interrupted.

[0091] However, there is a permanent connection between U from the power input 6 to Ul from the power output 7 , as well as between V and VI and between W and Wl .

[0092] The third switching contact, however, is closed in the first switching position and thus connects the lines U2 and U3 of the power output 7. The second switching contact, like the first switching contact, is open in the first switching position, and the connection between U2 and W2 is therefore interrupted.

[0093] The fourth, fifth and sixth switching contacts serve in the same way to connect V2 with V3 in the first switching position and to separate the connection between V2 and V3 in the second active switching position and to connect V1 with V3 and V2 with W2.

[0094] The eighth switching contact connects W2 to W3 in the first switching position and separates this connection in the second switching position, while the seventh switching contact connects the power outputs Wl and W3 which are separated in the first switching position in this switching position.

[0095] Figure 2a also shows the second switching module 4 already described, which is designed as an electromagnetic switch that is controlled via a switching input “STO”.

[0096] Finally, the switching device 1 in Figure 2a also comprises an overvoltage module 5 which is intended to limit overvoltages.

[0097] The power outputs Ul , VI , Wl , U2 , V2 , W2 and U3 , V3 , W3 are connected in parallel to the nine inputs of the traction motors 8a and 8b.

[0098] Figure 2b shows a further embodiment of the switching device 1, which differs from the above-described embodiment of Figure 2a, in particular by a variant of the first switching module 2. All eight switching contacts are designed as normally open contacts, i.e., in the first inactive switching position, they interrupt the lines connected to them and, in the second active switching position, establish a connection between these lines.

[0099] The eight switching contacts are divided into a first subset of five switching contacts, which are activated by a first switching input "SHI FT-A", and a second subset of three switching contacts, which are controlled by another switching input "SHI FT-B".

[0100] The first, third and fifth switching contacts separate and connect Ul and U3, VI and V3 and W1 and W3 respectively.

[0101] The second switching contact separates or connects U2 and W2, the fourth V2 and W2.

[0102] The sixth switching contact separates or connects U2 and U3, the seventh V2 and V3 and the eighth W2 and W3.

[0103] Figures 3a and 3b show how the two switching positions of the first switching module 2 of the switching device 1 result in the two different configurations of a double star connection or a star connection of the winding phase groups 11a, 11b, 11c, 11d, 11e and 11f of the traction motors 8a, 8b.

[0104] The winding phase group 11a is located between the

[0105] Switching terminals Ul and U2 of a traction motor 8a, 8b and the winding phase group 11b between the switching terminal U3 and the unchangeable first star point SP1. Similarly, the winding phase group 11c is located between V1 and V2, the winding phase group l1d between V3 and the first star point SP1 and the winding phase group Ile between W1 and W2, while the winding phase group llf is arranged between W3 and the common first star point SP1.

[0106] Figure 3a shows the second active switching position of the first switching module 2 of the switching device 1 in which two winding phase groups 11a and 11b, 11c and 11d as well as 11e and 11f are arranged parallel to one another per phase and the two sides of the winding phase groups 11a, 11c and 11f facing away from the phases U, V and W are connected to a second star point SP2 in addition to the fixed first star point SP1 of the winding phase groups 11b, 11d and 11f.

[0107] In Figure 3b, the winding phase groups 11a, 11b, 11c, 11d, 11e and 11f are arranged in a star connection with the first unchangeable star point SP1.

[0108] For each phase U, V, W of the three-phase system, which is generated by a converter 15 with adjustable voltage and frequency f, two winding phase groups 11a and 11b, 11c and 11d as well as 11e and 11f are connected in series.

[0109] This arrangement is made possible by connecting U2 and U3 while simultaneously separating the connection between Ul and U3. As in Figure 3a, phase U is connected to terminal Ul of winding phase group 11a.

[0110] In the same way, phase V with VI of the

[0111] Winding phase group 11c is connected and its second terminal V2 is connected to V3 of winding phase group 11d, whose second terminal together with terminals of winding phase groups 11b and 11f form the star point.

[0112] This also applies to phase W, which is connected to W1 of the winding group I le , where W2 of this winding phase group I le is connected to W3 of the winding phase group llf .

[0113] In Figure 3c, the winding phase groups 11a to 11f are arranged in a double star just as in Figure 3a, but the two separate star points SP1 and SP2 are connected to a common star point by a further switchable connection, in particular between U2 and the fixed star point SP1.

[0114] With this configuration of the winding phase groups 11a to 11f, it must be ensured that at the interface of the winding system of the traction motor 8a, 8b, in particular at the motor terminal board, the fixed star point SP1 is available as the tenth connection in addition to the nine connections for Ul, U2, U3, VI, V2, V3 as well as Wl, W2 and W3 for external wiring.

[0115] Such an arrangement of the winding phase groups 11a to 11f with a common star point SP1 means in the present case that the number of poles 2p and thus the number of pole pairs p does not change, while the other traction motor parameters, in particular the inductance L n and the resistance R n, are unchanged compared to the arrangement of the winding phase groups 11a to 11f as a double star with two separate star points SP1 and SP2 according to Figure 3a. Figures 7a, 7b and 7c each show the interconnections of the winding phase groups in the double star with two separate star points SP1 and SP2 according to Figure 3a, in a star connection according to Figure 3b and in a double star connection with a common star point SP1 according to Figure 3c in an alternative view.

[0116] In this view, the winding phase groups 11a and l lb, 11c and l ld as well as I le and llf , each of which is assigned to one of the three phases U, V, W of the three-phase system provided by the converter, are shown one above the other to illustrate the concept of group switching and the common fixed star point SP1 is found on the right-hand side.

[0117] SP1 is the interconnection of terminal U4 of winding phase group 11b, terminal V4 of winding phase group l ld and terminal W4 of winding phase group llf .

[0118] The connections switched by the switching device 1 are shown in dashed lines in Figures 7a, 7b and 7c.

[0119] Figures 4a and 4b show, as an example and in a simplified manner, the curve of the voltages 12a, 12b, currents 13a, 13b, and the resulting traction force 14a, 14b of the traction motor 8a, 8b versus the speed v of the rail vehicle 19 for both switching positions of the switching device 1 and the corresponding connection variants of the winding phase groups 11a, 11b, 11c, 11d, 11e, and 11f. Figure 4a shows the first passive switching position, which corresponds to the star connection of the winding phase groups 11a, 11b, 11c, 11d, 11e, and 11f from Figures 3b and 7b.

[0120] In the section of the linear increase of the voltage 12a up to the speed v B current 13a and traction force 14a remain constant. v B is for example between 3km / h and 7 km / h and preferably between 4 km / h and 6km / h.

[0121] In the following section with constant voltage 12a and degressively decreasing traction force 14a the current remains constant up to an unspecified speed before it increases in the last section with further increase of the speed up to the intended maximum speed v max decreases . v max is, for example, between 50km / h and 150km / h and preferably between 80km / h and 120km / h.

[0122] The current 13a has the highest value I in the first two speed sections maXf 2 which, according to Figure 4a, for example, I maXf 2 =200A is .

[0123] If the speed v Bthe current 13a* is further increased, the traction force 14a* can still be used for speeds v>v B be kept constant at its maximum value.

[0124] According to Figure 4a, the current 13a* reaches a maximum value of I maXf 2 =300A ​​at a maximum

[0125] Traction force of 40 kN. In contrast, Figure 4b shows the curve of voltage 12b, current 13b and traction force 14b over the speed v of the rail vehicle 19 for the second active switching position of the switching device 1, which corresponds to the double star connection of the winding phase groups 11a, 11b, 11c, 11d, 11e and 11f from Figures 3a and 7a.

[0126] In this case, current 13b and traction force 14b remain in a first section up to an unspecified speed between v B and a speed v A constant , while the voltage 12b increases linearly with the speed v .

[0127] The value of current 13b in this section is more than 400A and is thus significantly higher than the values ​​of currents 13a and 13a* from Figure 4a in this speed range.

[0128] In a second section , which corresponds to the speed range between v A and v max , the tension value 12b is constant, the traction force 14b decreases degressively up to a residual traction force which is at v max occurs .

[0129] This residual tensile force is between 5 kN and 15 kN and preferably between 8 kN and 12 kN.

[0130] The current intensity 13b initially decreases gradually to an unspecified speed and then increases to v max again .

[0131] The value of the current 13b at v maxis, for example, between 250A and 350A and preferably between 280A and 320A. In Figure 4c, characteristic curve fields 12a, 13a or . 13a* and 14a or . 14a* from Figure 4a as well as 12b, 13b and 14b from Figure 4b are shown together.

[0132] An optimal switching condition in the operating range B between the switching position corresponding to the double star connection according to Figure 3a and that switching position of the switching device 1 corresponding to the star connection from Figure 3b is a value of the current intensity 13b approximately equal to the value of the current intensity 13a, wherein the traction force 14b is approximately equal to the traction force 14a.

[0133] In the case shown in Figure 4c, such an optimal switching condition does not exist.

[0134] If, according to the characteristic curve fields 12a, 13a or . 13a* and 14a or . 14a* as well as 12b, 13b and 14b in the operating switchover range B from Figure 4c, a switch is made between a first operating range "transfer travel" which is defined by the speed range between v A and v max and the second operating range "working mode" with speeds less than or equal to v B switched , the resulting reduction in traction force at the switching speed v not shown in Figure 4c is u acceptable because the rail vehicle 19 remains in operating area B only for a short time relative to the total operating time.

[0135] Optimization can be achieved by shifting the characteristic curves towards higher speeds v .

[0136] For example, the current 13a can be increased to a value of up to 300A, corresponding to the current 13a* in Figure 4a. However, the current characteristic curve 13b can also be shifted so far that its renewed increase only occurs at speeds v>v max and thus outside the used speed range.

[0137] Figure 5 shows a traction system 18 with three traction drives, each comprising a power converter 15, a switching device 1 and two traction motors 8a and 8b.

[0138] A control module 16 includes a communication module which is connected by means of a communication connection 17 both to the switching devices 1 and to the power converters 15 and which controls the traction motor parameters { L n , R n , p} is determined and transmitted .

[0139] Figure 6 shows a rail vehicle 19 with a pantograph 20 designed as a pantograph on a schematic section of a rail track 21.

[0140] The rail vehicle 19 is in two parts, the first part comprising the pantograph 20 and a bogie 22 and on the second part with a total of three bogies 22 between the second and the last bogie 22, as a rule, at least one of the working units described above is arranged.

[0141] These working units are not shown for the sake of better readability of Figure 6. The traction motors 8a and 8b are each intended to set one of the two drive axles of a bogie 22 in Figure 6 into rotational motion.

[0142] A switching device 1 with a control module 3 is assigned to these traction motor pairs 8a, 8b.

[0143] A communication connection 25 connects the control modules 3 of the switching devices 1 to at least one central control device 23 of the rail vehicle 19 and to at least one control module 16 which is assigned to an arrangement comprising at least one power converter 18.

[0144] This converter arrangement 18 is intended to generate a three-phase system U, V, W of adjustable voltage and frequency f from the current of the not shown electrical overhead line of the rail track 21, which is tapped by means of line 26 from the current collector 20, by converting the type of current and / or frequency.

[0145] A connecting line 24 is provided to supply this three-phase system U, V, W to the traction motor pairs 8a, 8b of the bogies 22 by means of a switching device 1.

[0146] When switching between the different configurations of the winding phase groups 11a, 11b, 11c, l ld, l le and llf, the winding system is separated from the three-phase system for a certain period of time for demagnetization as described above.

[0147] It is advantageous if the different bogies

[0148] 22 assigned switching devices 1 also carry out these switching operations on the traction motors 8a, 8b assigned to them in a staggered manner.

[0149] For a favorable embodiment of the switching device 1, which is configured multiple times for more than one driven bogie 22, the switching of these switching devices 1 is staggered in time. This allows the brief, cumulative drop in tractive force of all driven bogies 22 when passing through the switching area B to be minimized by the staggered timing.

[0150] Alternatively, the power converters 15 can be arranged together with the switching devices 1 directly above the bogies 22.

[0151] In such an embodiment, the connecting line 24 is, for example, a direct current line with a direct voltage between 500V and 1.5kV.

[0152] Such an alternative arrangement and supply of the power converters 15 is particularly advantageous in order to further reduce or prevent undesired radiation of electromagnetic fields and to increase the electromagnetic compatibility (EMC) of the overall arrangement.

[0153] The subject matter of the invention is not limited to the exemplary embodiments described. Further switching configurations of the switching device 1 and its arrangement with the power converter 15 and traction motors 8a, 8b in rail vehicles 19 and rail vehicle assemblies are also encompassed by the claims.

Claims

Patent claims 1. Switching device (1) for a traction system (18) of a rail vehicle (19), comprising: - a first switching module (2) with power inputs (6) for connection to a power converter (15), with power outputs (7, 7a, 7b) for connection to at least one traction motor (8a, 8b) and with switching elements for carrying out a group switching between the power inputs (6) and the power outputs (7, 7a, 7b) dependent on a predetermined operating range of the traction motor (8a, 8b), - a communication module for transmitting traction motor parameters {L n , R n , p} to the power converter (15) depending on the specified operating range.

2. Switching device (1) according to claim 1, characterized in that a control module (3) is provided to trigger and / or monitor the group switching dependent on the operating range and / or to control the traction motor parameters {L n , R n , p} to the power converter (15).

3. Switching device (1) according to one of claims 1 or 2, characterized in that a second switching module (4) is provided for a safe torque off shutdown and / or for the galvanic isolation of the power input (6) from the first switching module (2) and / or from the power outputs (7, 7a, 7b).

4. Switching device (1) according to one of claims 1 to 3, characterized in that an overvoltage module (5) is designed to reduce or avoid overvoltages between the traction motors (8a, 8b) and the power converter (15).

5. Switching device (1) according to one of claims 1 to 4, characterized in that the first switching module (2) is provided for carrying out a group switching between phases (U, V, W) of the power inputs (6) and winding phase groups (11a, 11b, 11c, 11d, 11e, 11f) of the traction motor (8a, 8b) which are connected to the power outputs (7, 7a, 7b), between a double star configuration for a first operating range and a star configuration for a second operating range.

6. Switching device (1) according to one of claims 1 to 5, characterized in that it is provided to connect the power converter (15) to at least two traction motors (8a, 8b) of a bogie (22) of the rail vehicle (19).

7. Traction system (18) for a rail vehicle (19) with at least one power converter (15), characterized in that the power converter (15) is connected to a switching device (1) according to one of claims 1 to 6 and that a control module (16) of the at least one power converter (15) is provided to trigger and / or monitor the group switching dependent on the operating range and / or to transmit the traction motor parameters {L n , R n , p} from the switching device (1).

8. Traction system (18) according to claim 7, characterized in that a wired or wireless communication connection (25) is set up between the communication modules of the at least one power converter (15) and the switching device (1) and it is provided that the transmission of data and signals takes place in an analog and / or digitally coded manner.

9. Rail vehicle (19) with working units and with a speed-adjustable traction drive which contains at least one power converter (15), provided for controlling traction motors (8a, 8b) which are designed to drive axles of the rail vehicle (19), wherein the used speed range of the traction motors (8a, 8b) is characterized by a first operating range in which the rail vehicle (19) is provided to work a rail track (21) with its working units, and a second operating range in which the rail vehicle (19) is provided to travel on the rail track (21) without this being affected by the Working units are processed, characterized in that a switching device (1) according to one of claims 1 to 6 is arranged between the at least one power converter (15) and at least one traction motor (8a, 8b).

10. Rail vehicle (19) according to claim 9, characterized in that all power converters (15) of the traction drives are arranged in a housing (18).

11. Rail vehicle (19) according to claim 9, characterized in that the traction drives with their power converters (15) are partially or entirely in the environment the drive axles of the rail vehicle (19) are arranged.

12. Rail vehicle (19) according to one of claims 9 to 11, characterized in that the traction drives with their power converters (15) are provided to be supplied by means of a direct current line (24) arranged in the rail vehicle (19).

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