Power modulation-based charging

Abstract

The present invention relates to a method (100; 200) for charging a battery (22) of a rail vehicle (20; 40) at a charging station (10), as well as a rail vehicle (20; 40) and a system (50). In the method (100), the rail vehicle (20) is electrically connected (S1) to a charging network (12) of the charging station (10). Furthermore, a frequency analysis is performed in the charging network (12) (S2), and a charging power level (P_L) is determined based on the frequency analysis (S3). Finally, the battery (22) is charged with a charging power (P_N) (S4) that is essentially at the charging power level (P_L).

Description

[0001] The present invention relates to a method for charging a battery of a rail vehicle at a charging station, as well as a rail vehicle and a system.

[0002] Battery-powered or battery-hybrid trains are commonly used on non-electrified tracks. Battery-hybrid trains can operate both under overhead lines using pantographs and on battery power alone on non-electrified sections. Occasionally, it is necessary to recharge the train's traction batteries. If such recharging is required on a non-electrified section, for example, at a terminal station without an electrified track, dedicated charging stations can be installed. These charging stations, also known as "charging islands," provide a short section of overhead line, allowing several trains to be charged simultaneously.

[0003] Charging stations are often located in areas far from high-voltage power lines. The electrical supply for these charging stations is therefore usually provided by local grids via a transformer. However, such local grids can typically only supply a small amount of electrical power compared to the maximum charging capacity of the traction batteries. Consequently, it is often necessary to actively limit the actual charging power of a train charging at the charging station. If several trains are charging simultaneously, the power available from the charging station's grid transformer must be divided among them.

[0004] Against this background, it is an object of the present invention to improve the charging process at a charging station, in particular to enable a situation-dependent and / or individual limitation of the charging power.

[0005] This problem is solved by a method for charging a battery of a rail vehicle at a charging station, a rail vehicle and a system according to the independent claims.

[0006] Preferred embodiments of the invention are the subject of the dependent claims and the following description.

[0007] According to a first aspect of the invention, in the method for charging a rail vehicle battery at a charging station, preferably at least partially implemented by computer, the rail vehicle is electrically connected to the charging station's charging network. Furthermore, a frequency analysis is performed on the charging network, and a charging power level is determined based on this analysis. Finally, the battery is charged with a charging power that is essentially at the determined charging power level.

[0008] A frequency analysis within the meaning of the present invention is preferably the analysis of a frequency spectrum, i.e., a plurality of frequencies, in the charging network. In the frequency analysis, for example, the fluctuations of the electrical power supplied to a rail vehicle via the charging network, and in particular small fluctuations in the network voltage, can be analyzed. The frequency analysis can be performed, for example, by means of a Fourier analysis of the charging power or the network voltage.

[0009] One aspect of the invention is based on the approach of charging a rail vehicle with a charging power that depends on the result of a prior frequency analysis in a charging network. This approach takes advantage of the fact that the frequencies occurring in the charging network depend on the current load of the network or may even have been deliberately imposed. Based on the determined frequencies and / or frequency changes, a charging power level for the rail vehicle can thus be dynamically determined. In particular, the charging power level can be set situationally and flexibly. For example, the simultaneous charging of other rail vehicles, which also consume a portion of the power provided in the charging network, can be taken into account.

[0010] Frequency analysis allows information to be received or at least derived. For example, it can determine how many other rail vehicles are connected to the charging station, i.e., electrically connected to the charging network, or are currently drawing charging current from the network. This information can then be taken into account when charging the rail vehicle's battery.

[0011] Accordingly, the specified charging power level appropriately characterizes a charging power at which there is no risk of overloading the charging network.

[0012] The rail vehicle, or rather its battery, can in principle be charged with a constant charging power corresponding to the charging power level. Preferably, however, the battery is charged with a modulated charging power that fluctuates around the charging power level, as will be explained in more detail below in connection with the second aspect of the invention. For example, the battery can be charged with a charging power that fluctuates around the charging power level with an amplitude of approximately 1 to 2% of the charging power level.

[0013] Generally speaking, frequency analysis in the charging network, particularly of the available or drawn power or the network voltage, enables the reception of signals. Consequently, frequency analysis can allow communication between the rail vehicle and the charging network, for example, via an overhead line at the charging station. This allows the rail vehicle to communicate with other rail vehicles connected to the charging network or with the charging station itself.

[0014] Preferred embodiments of the invention and their further developments are described below. These embodiments can be combined with each other and with the aspects of the invention described below, unless expressly excluded.

[0015] In a preferred embodiment, frequency analysis, particularly of predetermined modulation frequencies, is used to determine modulation frequencies within the charging network. The charging power level is preferably determined based on these determined modulation frequencies. Advantageously, frequencies are identified that are used to selectively modulate the power or voltage in the charging network by other rail vehicles or by the charging station itself. Individual modulation frequencies can be assigned to specific rail vehicles. In other words, each rail vehicle can be assigned an individual, predetermined modulation frequency by which it can be identified. Through frequency analysis, i.e., the determination of the modulation frequencies within the charging network, other rail vehicles also connected to or currently charging in the network can be identified and, for example, counted.The presence or charging process of these other rail vehicles can then be taken into account when charging the battery.

[0016] In another preferred embodiment, a number of modulation frequencies in the charging network are determined. The charging power level is then preferably set by dividing a predetermined maximum charging power of the charging station by a number based on the number of determined modulation frequencies. For example, the maximum charging power can be divided by a number one greater than the number of modulation frequencies; i.e., for example, P_L = P_max / (n + 1) where P_L is the charging power level, P_max is the maximum charging power of the charging station, and n is the number of determined modulation frequencies or the number of other rail vehicles currently charging.

[0017] This allows the available charging station power to be distributed precisely, and in particular evenly, among all rail vehicles electrically connected to the charging network. This prevents exceeding the maximum charging power specified, for example, by the local grid supplying the charging station.

[0018] In a further preferred embodiment, the frequencies of voltage fluctuations in the charging network are determined during frequency analysis. Preferably, peaks in the frequency spectrum above and below the network frequency are identified; these can also be referred to as sidebands of the network frequency. It can be assumed that regular voltage fluctuations are artificially generated by modulation. Communication signals from other rail vehicles or the charging station itself can then be filtered out from these voltage fluctuations.

[0019] It is advantageous to also monitor temporal changes in the frequency spectrum of the charging network during frequency analysis. These temporal changes can be evaluated, allowing information to be extracted from the frequency spectrum that goes beyond the mere presence of certain modulation frequencies.

[0020] Accordingly, in a further preferred embodiment, the charging power level is determined based on charging information derived from temporal changes in the frequency spectrum of the charging network. Information can thus be provided or received via the charging network, for example, through frequency shift keying. Frequency shift keying can be performed by the charging station itself or by other rail vehicles. Consequently, entire messages containing additional information, such as the current charging status at the charging station or charging schedules of other rail vehicles, can be sent or received via the charging network. This information can then be taken into account when determining the charging power level.

[0021] For example, the charging station can allocate charging power individually and depending on the situation, for example according to a charging plan of a rail vehicle.

[0022] In a further preferred embodiment, the charging information therefore includes a charging power level assigned to the rail vehicle by the charging station. This allows the rail vehicle, or rather its battery, to be charged with a higher charging power if its battery is very low or if only a short charging time is available. Conversely, the rail vehicle can be charged with a lower charging power if the battery is already very full or if the rail vehicle is expected to remain connected to the charging network for an extended period.

[0023] Alternatively or additionally, information provided by other rail vehicles can also be taken into account when determining charging power levels. For example, it is conceivable that the rail vehicle independently determines a charging power level that considers, for instance, the charging schedules or battery levels of other rail vehicles.

[0024] In another preferred embodiment, the charging information includes a charging status of another rail vehicle electrically connected to the charging network.

[0025] In this context, a state of charge refers to information relating to and / or characterizing the charging of the rail vehicle in question. A state of charge can include, for example, a charging schedule, battery charge level, current charging current, and / or similar information.

[0026] This allows the rail vehicle to be charged at a lower charging rate if its battery is fuller than that of the other rail vehicle or if it can remain connected to the charging network for a longer period. Conversely, the rail vehicle can be charged preferentially, i.e., at a higher charging rate, if its battery is less charged than that of the other rail vehicle or if it cannot remain connected to the charging network for as long.

[0027] According to a second aspect of the invention, in the method for charging a rail vehicle battery at a charging station, preferably at least partially computer-implemented, the rail vehicle is electrically connected to a charging current network of the charging station. Furthermore, a charging power level is defined, and a charging power essentially at this level is modulated at at least one predetermined frequency. The battery is then charged with the modulated charging power.

[0028] The predetermined frequency preferably corresponds to a frequency assigned to the rail vehicle. The predetermined frequency can therefore be rail vehicle-specific. Advantageously, the predetermined frequency serves to identify the rail vehicle. In particular, the rail vehicle can differ from other rail vehicles with respect to its predetermined frequency. The predetermined frequency is advantageously lower than the grid frequency of the charging network, so that the modulation can occur as sidebands of the grid frequency in the charging network.

[0029] By modulating the charging power according to the charging power level, the rail vehicle can feed information into the charging network. This allows the rail vehicle to communicate via the charging network, for example with other rail vehicles or with the charging station, without requiring additional infrastructure. By modulating the charging power at a predetermined frequency, the rail vehicle can "register" with the charging network, signaling to other rail vehicles and / or the charging station that it has also connected electrically to the charging network and / or is charging its battery with power from the network.

[0030] The charging power can be modulated at a predetermined frequency, for example, using a sinusoidal waveform, such as the formula I_N = I_L + I_M·sin(2·π·f), where I_N is the (modulated or actual) charging current at the battery, I_L is the constant charging current component, I_M is the current modulated for communication, and f is the predetermined frequency. This assumes at least an approximately constant voltage at the battery, so the currents can be considered proportional to the respective power levels. Consequently, I_N can correspond to the actual (modulated) charging power, and I_L to the defined charging power level P_L. I_M, however, corresponds to a modulated power that is expediently a maximum of approximately 0.4%, preferably a maximum of 0.2%, of the charging power level P_L. The modulated power can be, for example,between 1 per mille and 2 per mille of the charging power level, meaning that the resulting load peaks in the charging network are negligible and do not endanger network stability.

[0031] In principle, the modulation should be as small as possible, but high enough to be reliably detected. For interference current measurements, (high-frequency) currents in the range of 100 mA can be measured using narrow bandpass filters. This can serve as a guideline; in the charging network of a rail vehicle charging station, it can be assumed that approximately 1 kVA of apparent or modulation power can be reliably and robustly detected.

[0032] The modulation of the charging power or current is transmitted to the charging network. This is because every power or current draw from the charging network, for example from an overhead line of the charging station, affects the network or overhead line voltage due to secondary leakage inductances and secondary resistance. These leakage inductances and secondary resistances are created, for example, by the cable routing, components of the cable, and especially the network transformer through which the charging network is connected to a local grid.

[0033] A modulated charging current at the battery will therefore cause voltage modulation in the charging network or at least influence the network voltage in a characteristic way. As described above, this can be used by other rail vehicles to identify the rail vehicle modulating the charging current.

[0034] In a preferred embodiment, the charging power is modulated such that information concerning the identity of the rail vehicle, a charging plan for the rail vehicle, in particular a maximum charging duration, a battery charge level, a required minimum amount of energy, and / or the like, is made available in the charging network. For this purpose, the charging power can be modulated, for example, according to a frequency shift keying method, such as to represent bit sequences and thus imprint a message on the charging network. The charging station and / or other rail vehicles can thus adjust or distribute the charging power as needed or depending on the situation. For example, a vehicle with an empty battery or only a scheduled short stop at the charging station can be prioritized, i.e.,with higher charging power, while another rail vehicle with a full battery and / or a planned long stay at the charging station can be charged with lower charging power.

[0035] The method according to the first aspect of the invention and the method according to the second aspect of the invention are related to each other. In particular, the method according to the first aspect of the invention and the method according to the second aspect of the invention, taken together, ensure that communication via the charging network is possible, for example, between two different rail vehicles and / or between a rail vehicle and the charging station. The method according to the first aspect of the invention represents the receiver side of the communication, while the method according to the second aspect of the invention represents the transmitter side of the communication. In this respect, the two methods are related to each other in such a way that they realize a single general inventive idea, analogous to a transmitter and a receiver or a plug and the corresponding socket.Both methods rely on modulating the voltage in the charging network. In one case, the modulation is analyzed ("received"), in the other case, the modulation is generated ("send").

[0036] According to a third aspect of the invention, the rail vehicle comprises: i) a battery; ii) a mains connection for connecting the rail vehicle to a charging network of a charging station; iii) a converter arrangement which electrically couples the mains connection to the battery and is configured to provide charging power drawn from the charging network to the battery; and iv) a control device which is configured to perform a frequency analysis in the charging network, to determine a charging power level based on the frequency analysis, and to initiate charging of the battery with a charging power that is substantially at the determined charging power level.

[0037] For example, a voltage measurement can be taken at the mains connection, such as at a pantograph of the rail vehicle. The control device is then expediently configured to analyze the voltage measured at the mains connection. The control device can thus, for example, detect regular fluctuations in the mains voltage and their frequencies. In particular, the control device can perform a Fourier analysis of the measured voltage. To charge the battery, the converter arrangement, especially a DC-DC converter within the converter arrangement, can then be controlled accordingly by the control device.

[0038] Frequency analysis and the subsequent determination of the charging power level allow the presence of other rail vehicles at the charging station, and in particular the charging process of other rail vehicles, to be detected and taken into account. Frequency analysis thus allows information to be received from other rail vehicles and / or from the charging station.

[0039] According to a fourth aspect of the invention, the rail vehicle comprises: i) a battery; ii) a mains connection for connecting the rail vehicle to a charging current network of a charging station; iii) a converter arrangement which electrically couples the mains connection to the battery and is configured to provide charging power drawn from the charging current network to the battery; and iv) a control device which is configured to define a charging power level and to modulate a charging power corresponding to the charging power level with at least one predetermined frequency.

[0040] The control device can, for example, be configured to control the converter arrangement, in particular the DC-DC converter, accordingly. As mentioned above, the predetermined frequency is preferably vehicle-specific. Consequently, the rail vehicle can be identified in the charging network using the predetermined frequency. By modulating with the predetermined frequency, the rail vehicle can "register" itself in the charging network. Furthermore, it is also possible to provide more complex information about the charging network by modulating the charging power, for example, by mapping corresponding bit sequences using frequency shift keying. In this way, the rail vehicle can inform other rail vehicles also connected to the charging network and / or the charging station itself about the charging and / or vehicle status.

[0041] Analogous to the method according to the first aspect of the invention and the method according to the second aspect of the invention, the rail vehicle according to the third aspect of the invention and the rail vehicle according to the fourth aspect of the invention are also related to each other. In this respect, the two rail vehicles are also connected to each other in such a way that they realize a single general inventive idea. In the rail vehicle according to the third aspect of the invention, the control device is configured as a receiver, while in the rail vehicle according to the fourth aspect of the invention, it is configured as a transmitter.

[0042] The control device can be designed using hardware and / or software. In particular, the control device can include a processing unit, preferably connected to a memory and / or bus system via data or signals. For example, the control device can include a microprocessor unit (CPU) or a module thereof, and / or one or more programs or program modules. The control device can be configured to execute instructions implemented as a program stored in a memory system, to acquire input signals from a data bus, and / or to output signals to a data bus. A memory system can include one or more, in particular different, storage media, especially optical, magnetic, solid-state, and / or other non-volatile media. The program can be designed such that it at least partially embodies the methods described herein.is capable of performing, so that the control device can carry out at least part of the steps of such methods and thus, in particular, can charge a battery of a rail vehicle at a charging station, preferably via communication with at least one other rail vehicle and / or the charging station via the charging network.

[0043] According to a fifth aspect of the invention, the system comprises a charging station and a vehicle according to the third or fourth aspect of the invention. The charging station is advantageously configured to perform a frequency analysis in a charging network of the charging station and / or to modulate a network voltage of the charging network with at least one predetermined frequency. The charging station can accordingly be designed as a "smart" charging station that can communicate with rail vehicles connected to the charging network or at least monitor communication between the rail vehicles. For example, the charging station can detect the status of the connected rail vehicles and, if necessary, send charging information for a selected rail vehicle via the charging network. This allows charging to be controlled dynamically and situationally, and the charging power to be distributed accordingly.

[0044] The properties, features, and advantages of the invention described above, as well as the manner in which they are achieved, are explained in more detail in the following description of exemplary embodiments of the invention in conjunction with the figures. Where appropriate, the same reference numerals are used in the figures for the same or corresponding elements of the invention. The exemplary embodiments serve to illustrate the invention and do not limit the invention to the combinations of features specified therein, including functional features. Furthermore, all features specified in the exemplary embodiments can be considered in isolation and combined appropriately with the features of any claim.

[0045] They show: Fig. 1 an example of a rail vehicle connected to a charging network of a charging station; Fig. 2 an example of a method for charging a rail vehicle battery; and Fig. 3. An example of a system with a charging station and a rail vehicle.

[0046] Fig. Figure 1 shows an example of a rail vehicle 20 connected to a charging network 12 of a charging station 10. The charging station 10 includes a network transformer 14, which can be connected to an external power grid, for example, a local grid, and supplies electrical power to an overhead line section representing the charging network 12. The rail vehicle 20 is designed as a battery-hybrid rail vehicle, whose drive system (not shown) can be supplied with electrical energy both via the network connection 24 from an overhead line and by a battery 22. Therefore, the rail vehicle 20 has a pulse inverter 28, which can convert the DC voltage provided by a rectifier 34 or the battery 22 as needed to operate the drive system (not shown).

[0047] The battery 22 is also electrically connected to the mains connection 24 via the rectifier 34 and a DC-DC converter 36. Together, the rectifier 34, e.g., a four-quadrant converter, and the DC-DC converter 36 form a converter arrangement 26. The converter arrangement 26, in particular the DC-DC converter 36, can be controlled by a control device 38.

[0048] The network connection 24 includes a pantograph 30 and a train transformer 32, with which a network voltage in the charging network 12 can be transformed down to a train voltage.

[0049] The rail vehicle 20 can draw a mains current I_Netz from the charging network 12 via the mains connection 24, in particular via the pantograph 30. This mains current I_Netz can be converted into a train current I_Zug by means of the train transformer 32. Since the charging network 12 is advantageously operated with a high alternating voltage, both the drawn mains current I_Netz and the corresponding train current I_Zug are alternating currents. The rectifier 34 is advantageously configured to convert the train current I_Zug into a substantially constant supply current I_V. This direct current can be used, possibly partially, to operate the drive (not shown) and to charge the battery 22.

[0050] To charge the battery 22, the DCDC converter 36, e.g. at the instigation of the control device 38, sets a charging current I_N at the battery 22, also referred to as "battery current" - and thus also a charging power P_N.

[0051] The control device 38 is preferably configured to define a charging power level P_L and to modulate the charging power P_N at the charging power level with at least one predetermined frequency.

[0052] Since the voltage at battery 22 is essentially constant, the charging power P_N can be modulated by modulating the charging current I_N. The control device 36 can therefore, for example, be configured to cause the DC-DC converter 36 to modulate the supply current I_V or a portion thereof I_L such that I_N=I_L+I_M⋅sin(2⋅π⋅f) with I_L: constant charging current component which corresponds to the specified charging power level, I_M: modulated current which is a maximum of approximately 4%, preferably a maximum of 2% of the constant charging current component I_L, and f: predetermined frequency.

[0053] Alternatively or additionally, the control device 38 is configured to perform a frequency analysis in the charging network 12. Furthermore, the control device 38 can determine the charging power level P_L based on the frequency analysis. To perform the frequency analysis in the charging network 12, i.e., for example, to determine the voltage frequencies in the charging network 12, the control device 38 can initiate and evaluate a current measurement at the network connection 24, in particular at the current collector 30.

[0054] Fig. Figure 2 shows an example of two methods 100, 200 for charging a battery 22 of a rail vehicle 20, 40 in an equivalent circuit diagram.

[0055] In process step S1 of process 100, the rail vehicle 20 is electrically connected to a charging station 10, for example, by connecting a network connection 24 of the rail vehicle 20 to a charging current network 12 of the charging station. The charging current network 12 is expediently supplied by a network transformer 14. Thus, a train current I_train, transformed from a network current I_network at network connection 24 with a resistance R_Z and an inductance L_Z, can be provided at a converter arrangement 26. The train current I_train is converted into a direct current, referred to as the "supply current" I_V, by means of the converter arrangement 26, in particular a rectifier 34.

[0056] In a further process step S2, a frequency analysis is performed in the charging network 12. For this purpose, a voltage measurement can be taken at the network connection 24, for example. The frequency analysis in process step S2 can then be carried out, for example, by means of a Fourier analysis of the voltage measurement. The result of the frequency analysis is expediently a frequency spectrum which, in addition to the network frequency of the supply network 12 of, for example, 50 Hz, may exhibit further frequency peaks at frequencies above and below the network frequency. These additional frequencies occur as sidebands of the network frequency. The additional frequencies can be imposed on the network voltage in the charging network 12 by other rail vehicles 40, as will be explained in more detail below.

[0057] Based on the frequency analysis thus carried out, a charging power level P_L can be determined in a further process step S3, for example by means of a correspondingly configured control device 38. The charging power level P_L can therefore be determined, for example, by how many other rail vehicles 40 are currently also charging a battery 22 with a grid current I_Grid from the charging grid 12 (and thereby causing at least one pair of additional sidebands in the frequency spectrum).

[0058] If necessary, the charging network 12 can be monitored over a longer period, particularly over the entire charging duration, as part of process step S3, in order to detect changes in the frequency spectrum. Accordingly, the charging power level P_L can be changed during the charging process, for example, to adapt to a changed charging situation at charging station 10. Alternatively or additionally, more complex information can also be decoded using the changing frequency spectrum, allowing for even more differentiated control of the charging process. Examples of this include the state of charge of other rail vehicles 40, such as their battery charge level, any charging schedules, i.e., the maximum possible charging duration due to an upcoming departure, and / or the like.

[0059] In a further process step S4, the battery 22 is finally charged with a charging power P_N, which is essentially at the charging power level P_L. The charging power P_N is conveniently derived from a charging current I_N, which is provided by a DC-DC converter 36 of the converter arrangement 26 based on the supply current I_V at the battery.

[0060] In process 200, the rail vehicle 40 is also electrically connected to the charging network 12 in process step V1.

[0061] In a further process step V2, the charging power level P_L is determined, for example, by means of the control device 38. It is preferred that this determination is based on a frequency analysis performed in the charging network 12, analogous to process step S3 of process 100. However, this is not mandatory for process 200. Rather, it is important that in a further process step V3, a charging power P_N, which is essentially at the determined charging power level, is modulated with at least one predetermined frequency f. For this purpose, the control device 38 can control the DC-DC converter 36 accordingly. This modulation can, for example, be sinusoidal.

[0062] The modulated charging power P_N can be obtained, for example, by modulating a comparatively small current onto a constant charging current I_L corresponding to the charging power level P_L, such as the supply current I_V or a part thereof.

[0063] The modulation of the battery or charging current I_N results in a slightly fluctuating power demand. Consequently, the modulation of the charging current I_N at the predetermined frequency f propagates into the charging current network 12: First, the modulation of the charging current I_N causes a corresponding fluctuation in the supply current I_V in the converter arrangement 26, also known as the "intermediate link". The supply current I_V in the converter arrangement 26, which fluctuates at the frequency f, in turn leads to a fluctuating train current I_train on the secondary side of the train transformer (see Fig. 1) and ultimately also to a fluctuation in the current at the current consumer (see Fig. 1), i.e., the mains current I_Netz. The mains current I_Netz, which fluctuates with the frequency f, ultimately leads to a voltage modulation due to the mains impedance from the secondary resistance R_T and the secondary leakage inductance L_T of the charging current network 12. Although this has a small amplitude, it can be clearly identified in the frequency spectrum – for example, within the framework of the method 100 described above.

[0064] In a further process step V4, the battery 22 can finally be charged with the modulated charging power P_N.

[0065] Fig. Figure 3 shows a system 50 with a charging station 10 and a rail vehicle 20, which is configured for communication with other rail vehicles 40, 42 and / or the charging station 10 via a charging current network 12 of the charging station 10 supplied by a network transformer 14. For the purpose of this communication, each of the rail vehicles 20, 40, 42 is expediently configured to modulate a charging power for charging a battery of the respective rail vehicle 20, 40, 42 with a frequency f, f_1, f_2 assigned to the respective rail vehicle 20, 40, 42. As in connection with Fig. As described in section 2, each of the rail vehicles 20, 40, 42 and / or the charging station 10 can independently detect the presence of the other rail vehicles by means of a frequency analysis in the charging network 12 and thus individually calculate the charging power available for the respective rail vehicle 20, 40, 42.

[0066] Although the invention has been further illustrated and described in detail by the preferred embodiments, the invention is not limited by the disclosed examples and other variations can be derived from them by a person skilled in the art without leaving the scope of protection of the invention.

[0067] Regardless of the grammatical gender of a particular term, persons with male, female or other gender identities are included.

Claims

[1] Method (100) for charging a battery (22) of a rail vehicle (20) at a charging station (10), comprising: - electrical connection (S1) of the rail vehicle (20) to a charging current network (12) of the charging station (10); - Performing (S2) a frequency analysis in the charging current network (12); - Determining (S3) a charging power level (P_L) based on frequency analysis; and - Charging (S4) the battery (22) with a charging power (P_N) that is essentially at the charging power level (P_L). [2] Method (100) according to claim 1, wherein modulation frequencies within the charging network (12) are determined during frequency analysis and the charging power level (P_L) is determined on the basis of the determined modulation frequencies. [3] Method (100) according to claim 2, wherein a number of modulation frequencies in the charging network (12) is determined and the charging power level (P_L) is set by dividing a predetermined maximum charging power of the charging station (10) by a number based on the number of determined modulation frequencies. [4] Method (100) according to one of the preceding claims, wherein the frequencies of voltage fluctuations in the charging current network (12) are determined when performing the frequency analysis. [5] Method (100) according to one of the preceding claims, wherein the determination of the charging power level (P_L) is based on charging information which is determined on the basis of a temporal change of the frequency spectrum in the charging current network (12). [6] Method (100) according to claim 5, wherein the charging information includes a charging power level (P_L) allocated to the rail vehicle (20) by the charging station (10). [7] Method (100) according to claim 5 or 6, wherein the charging information includes a state of charge of another rail vehicle (40, 42) electrically connected to the charging network (12). [8] Method (200) for charging a battery (22) of a rail vehicle (20; 40) at a charging station (10), comprising: - electrical connection (V1) of the rail vehicle (20; 40) to a charging current network (12) of the charging station (10); - Setting (V2; S3) a charging power level (P_L); - Modulating (V3) a charging power (P_N) that is essentially at the charging power level (P_L) with at least one predetermined frequency (f); and - Charging (V4) the battery (22) with the modulated charging power (P_N). [9] Method (200) according to claim 8, wherein the charging power (P_N) is modulated such that information concerning an identity of the rail vehicle (20; 40), a charging plan of the rail vehicle (20; 40), in particular a maximum charging duration, a battery level, a required minimum amount of energy and / or the like is provided in the charging network (12). [10] Rail vehicle (20) with - a battery (22), - a network connection (24) for connecting the rail vehicle (20) to a charging current network (12) of a charging station (10), - a converter arrangement (26) which electrically couples the mains connection (24) with the battery (22) and is designed to provide charging power (P_N) drawn from the charging mains (12) to the battery (22), - a control device (38) which is configured to perform a frequency analysis in the charging current network (12), to determine a charging power level (P_L) on the basis of the frequency analysis and to initiate charging of the battery (22) with a charging power (P_N) which is essentially at the determined charging power level (P_L). [11] Rail vehicle (20; 40) with - a battery (22), - a network connection (24) for connecting the rail vehicle (20; 40) to a charging current network (12) of a charging station (10), - a converter arrangement (26) which electrically couples the mains connection (24) with the battery (22) and is designed to provide charging power (P_N) drawn from the charging mains (12) to the battery (22), - a control device (38) which is configured to define a charging power level (P_L) and to modulate a charging power (P_N) that is essentially at the charging power level (P_L) with at least one predetermined frequency (f). [12] System (50) comprising a charging station (10) and a vehicle (20, 40, 42) according to claim 9 or 10, wherein the charging station (10) is configured to perform a frequency analysis in a charging current network (12) of the charging station and / or to modulate a network voltage in the charging current network (12) with at least one predetermined frequency (f).

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