ARRANGEMENT WITH A VOLTAGE MODULE

Description

[0001] The invention relates, inter alia, to an arrangement with a voltage module comprising at least one battery and / or at least one fuel cell, wherein both module poles of the voltage module are insulated from a module housing of the voltage module by means of insulation.

[0002] In the field of rail vehicle and railway technology, rail vehicles will increasingly be equipped with voltage modules that may contain batteries as energy storage devices and / or fuel cells as energy sources.

[0003] The use of voltage modules of the type described in rail vehicles requires a long service life in order to avoid replacement costs, which can amount to up to 20% of the cost of the rail vehicles, and costly maintenance work, which can be extremely costly, especially in rail transport.

[0004] The service life of the voltage modules depends not only on the condition of the cells they contain, but also, among other things, on the insulation, as the risk of electric shock, short circuit, or fire must be minimized. Since the insulation must withstand vibrations, humidity, and temperature fluctuations over a service life of 15 to 30 years, particularly stringent manufacturing requirements apply.

[0005] Document DE 10 2014 220017 A1 discloses a battery system comprising a battery and a measuring device for measuring the insulation resistance of the battery. Document EP 3 620 800 A1 discloses a method for monitoring the insulation of a converter-fed power supply system. Finally, document DE 10 2018 124 109 A1 discloses an insulation monitoring device.

[0006] The invention is based on the object of specifying an arrangement with a voltage module which allows a particularly simple control of the insulation of the voltage module after production as well as during subsequent operation, for example while a vehicle equipped with the arrangement is driving.

[0007] This object is achieved according to the invention by an arrangement having the features according to patent claim 1 and by a method having the features according to patent claim 14. Advantageous embodiments of the arrangement according to the invention and of the method are specified in the respective dependent patent claims.

[0008] According to the invention, it is provided that an insulation characterization device is present which comprises at least one voltage supply device and a measuring device, wherein the at least one voltage supply device is suitable for applying a time-variable measuring voltage, in particular a sinusoidal or rectangular alternating voltage, to the insulation, and the measuring device is designed to detect occurring partial discharge currents which flow through the insulation and to generate a measurement result characterizing the insulation on the basis of the detected partial discharge currents.

[0009] A key advantage of the arrangement according to the invention is the evaluation of partial discharge currents to characterize the insulation. Partial discharge currents can be caused by defects within the insulation when external voltage is applied and have a frequency spectrum far above the operating frequencies typically encountered during normal operation of the arrangement. Partial discharge currents thus provide indications of insulation problems without destroying the insulation itself.

[0010] With a sinusoidal alternating voltage of, for example, 50 Hz or 100 Hz as the measuring voltage, partial discharge currents arise particularly in a frequency range between 100 kilohertz and 100 megahertz, typically in a frequency range between 1 and 5 MHz, whereby the frequencies depend particularly on the insulation material. The measuring device has a high measurement sensitivity in this frequency range in order to be able to detect the weak partial discharge currents. This high measurement sensitivity is achieved, for example, by providing a bandpass filter or due to a fundamental high-pass behavior as well as a large frequency separation between the measuring voltage and the partial discharge currents.

[0011] By monitoring for the occurrence of relevant partial discharge currents, better measurement results can usually be achieved with regard to insulation characterization than with simple resistance measurements, in which the insulation resistance is measured to form a resistance value and the resistance value is monitored for when it falls below a lower limit. This is particularly due to the fact that partial discharge currents can be evaluated not only in terms of amplitude but also in terms of frequency, and can thus indicate the occurrence of new defects in the insulation and / or the further deterioration of existing defects even earlier and more clearly than pure resistance measurements.

[0012] A further significant advantage of the arrangement according to the invention is that it enables monitoring of the insulation of the voltage module even during subsequent operation or use of the voltage module, for example while driving if the arrangement is used inside a vehicle.

[0013] It is advantageous to combine the detection and evaluation of any partial discharge currents flowing through the insulation during discharge events by means of the insulation characterization device with a simple ohmic resistance measurement, in which the ohmic resistance of the insulation is monitored for falling below a lower limit value, in order to be able to detect any unacceptable deterioration of the insulation properties in a timely manner with particularly high reliability.

[0014] It is also advantageous if the module housing is connected to a reference potential and a series circuit is connected to at least one of the module poles. The series circuit comprises a first partial impedance, a second partial impedance, and a center connection between the partial impedances, the center connection of which is connected to the reference potential. The partial impedances can contain resistive components, capacitive components, and / or inductive components, i.e., they can be resistive, resistive-capacitive, or resistive-inductive.

[0015] In an embodiment with two partial impedances, it is particularly advantageous if the at least one voltage supply device or at least one of the voltage supply devices of the insulation characterization device comprises the first or second partial impedance.

[0016] It is particularly advantageous if the at least one voltage supply device comprises a converter connected to the series circuit, which, through its operation and, for example, the interaction with the parasitic capacitances of the connected equipment (e.g. B. Motors, transformers) generates a time-varying voltage relative to the reference potential and acts as one of the voltage supply devices. In this case, the time-varying voltage forms or generates, at least indirectly, the measurement voltage for the insulation characterization device.

[0017] Alternatively or additionally, it can be provided that the at least one voltage supply device of the insulation characterization device comprises an additional voltage source which is electrically connected between one of the module poles and the module housing and / or in parallel to the first or the second partial impedance.

[0018] The measuring device is preferably electrically connected between one of the module poles and the module housing and / or electrically parallel to the first or second partial impedance.

[0019] The measuring device and the voltage source are preferably electrically connected in parallel, wherein both are each connected between one of the module poles and the module housing and / or electrically parallel to the first or second partial impedance.

[0020] The converter can advantageously connect the voltage module to a drive motor.

[0021] The converter preferably comprises a single-phase or multi-phase AC voltage side connected to the drive motor and a DC voltage side connected to the voltage module.

[0022] A DC / DC converter is preferably connected between the voltage module and the converter.

[0023] The measuring device preferably generates a warning signal or warning indication as a measurement result indicating insufficient insulation if the detected partial discharge currents are above a predetermined current threshold and / or indicate discharges above a predetermined discharge threshold.

[0024] When recording partial discharge currents, the measuring device can eliminate capacitive currents, which occur, for example, during normal operation of a converter and / or DC / DC converter, from its measurement results, for example by filtering out the operating frequencies occurring during operation of the converter and / or DC / DC converter from the current it records, for example by high-pass filtering. The filtered current or filtered current values ​​can then be integrated, for example, in terms of magnitude over predefined time windows, to form a discharge value indicating the respective discharge. The discharge value thus calculated can then be compared with the aforementioned discharge threshold. Of course, the partial discharge currents can also be recorded and evaluated in other ways.

[0025] In a preferred coupling of the measuring device, this and an isolating capacitance are connected in series.

[0026] The voltage module preferably comprises a fuel cell that is connected in parallel to the module poles directly or via a module-internal DC / DC converter.

[0027] The invention also relates to a vehicle, in particular a rail vehicle. According to the invention, the vehicle has an arrangement as described above.

[0028] With regard to the advantages of the vehicle according to the invention and advantageous embodiments of the vehicle according to the invention, reference is made to the above statements in connection with the arrangement according to the invention and its advantageous embodiments.

[0029] The invention also relates to a method for testing the insulation of a voltage module comprising at least one battery and / or at least one fuel cell, wherein both module poles are insulated from a module housing of the voltage module by means of the insulation. According to the invention, a voltage supply device applies a time-variable measuring voltage, in particular a sinusoidal or rectangular alternating voltage, to the insulation, detects any partial discharge currents flowing through the insulation, and generates a measurement result characterizing the insulation based on the detected partial discharge currents.

[0030] With regard to the advantages of the method according to the invention and advantageous embodiments of the method according to the invention, reference is made to the above statements in connection with the arrangement according to the invention and its advantageous embodiments.

[0031] In the method, it is advantageous if the method is carried out during operation, in particular during a journey, of a vehicle, in particular a rail vehicle, for testing the insulation of the voltage module.

[0032] The invention is explained in more detail below using exemplary embodiments; by way of example, Figure 1 shows an embodiment of an arrangement according to the invention in which a measuring voltage for a partial discharge measurement is generated by the converter operation of a converter of the arrangement, Figure 2 shows an embodiment of an arrangement according to the invention in which an additional voltage source is present for generating a measuring voltage for a partial discharge measurement, Figure 3 shows an embodiment of an arrangement according to the invention in which a voltage source alone generates a measuring voltage for a partial discharge measurement, Figure 4 shows an embodiment of an arrangement according to the invention in which an insulation monitoring device is integrated in an insulation resistance measuring device, Figure 5 shows a schematic representation of the occurrence of partial discharges due to defects in an insulation, and Figure 6 shows a possible course of partial discharge currents through the Figure 5 shown defects.

[0033] For the sake of clarity, the same reference symbols are always used in the figures for identical or comparable components.

[0034] The Figure 1 shows a first embodiment of an arrangement according to the invention 5 . The arrangement 5 comprises an electrical component 10, which may be, for example, a drive motor of a vehicle (not shown in detail), in particular a rail vehicle. The electrical component 10 is connected to a three-phase AC voltage side AS of a converter 20, which comprises a plurality of switching elements SE. The converter 20 may be, for example, a four-quadrant controller, a multilevel converter, or the like.

[0035] An intermediate circuit capacitance Cz is connected to a DC voltage side GS of the converter 20, across which a DC voltage Udc drops.

[0036] A series circuit 30 comprising a first partial impedance Z1 and a second partial impedance Z2 is connected in parallel to the intermediate circuit capacitance Cz. The partial impedances Z1 and Z2 can contain resistive, capacitive, and / or inductive components, i.e., they can be resistive, resistive-capacitive, or resistive-inductive. A center connection between the partial impedances Z1 and Z2 is connected to a reference potential BP (ground or earth potential) of the arrangement 5.

[0037] Parallel to the series circuit 30 are two converter-side connections 41 and 42 of a DC / DC controller 40, which in the embodiment according to Figure 1 a controller-specific capacitance Cs, two switches S1 and S2 and an inductance L.

[0038] A first module terminal 51 and a second module terminal 52 of a voltage module 50 are connected to voltage module-side terminals 43 and 44 of the DC / DC converter 40. The voltage module 50 comprises, in the embodiment according to Figure 1 a plurality of batteries 55. In addition or alternatively to the batteries, one or more fuel cells may also be present, each of which may be connected in parallel to the module poles 51 and 52 directly or via a DC / DC converter internal to the voltage module.

[0039] The module poles 51 and 52 are separated from a housing 53 of the voltage module 50 by means of an insulation 56, which for reasons of clarity is shown in the Figure 1 not shown in detail, is electrically insulated. Housing 53 is connected to the reference potential BP.

[0040] Order 5 according to Figure 1 further comprises a measuring device 100, which in the embodiment according to Figure 1 is connected in series with an isolating capacitance Cm via a coupling unit 110 and is thus connected together with the isolating capacitance Cm in parallel to the second partial impedance Z2 of the series circuit 30.

[0041] Due to the electrical interconnection of the measuring device 100, it is able to detect and quantitatively record partial discharge currents Ie that may flow through the insulation 56 of the voltage module 50 when a corresponding voltage is applied, in a measuring current Im and to generate a measurement result that characterizes the insulation properties of the insulation material of the insulation 56 on the basis of the measuring current Im or the recorded partial discharge currents Ie.

[0042] In other words, the measuring device 100 performs a partial discharge test on the insulation 56, as shown in the Figures 5 and 6is visualized as an example: If, for example, a measuring voltage Um of preferably at least 500 V with possibly superimposed DC voltage is applied between the second module pole 52 of the voltage module 50 and the operating potential BP, partial discharges can occur at defects FS (see Figure 5) in the insulation 56, which lead to partial discharge currents Ie. Figure 6 shows the partial discharge currents Ie over time t.

[0043] The partial discharge currents Ie can, for example, be integrated over predefined measurement time windows. The respective integration result can be compared with a limit threshold value, which has preferably been determined in a previous type test for the voltage module 50.

[0044] If the threshold value is not exceeded, the insulation 56 is of good quality and the voltage module 50 can continue to be used.

[0045] If, however, the limit threshold is exceeded, the measuring device 100 can generate a warning signal WS or a warning indication on the output side as the measurement result. The warning signal WS is thus generated when the detected partial discharge currents Ie or the corresponding measurement currents Im and the charge values ​​derived therefrom, for example, by integration, exceed a predetermined discharge threshold and thus indicate insufficient insulation 56.

[0046] In order to separate the partial discharge currents Ie from capacitive current components that can flow via the insulation 56 even without partial discharge effects, the measuring currents Im can be filtered, for example, by means of a high-pass filter, so that the evaluation of the measuring current Im is limited or focused on the actually relevant partial discharge currents Ie.

[0047] The time-variable measuring voltage Um is measured in arrangement 5 according to the Figure 1by a voltage supply device which is formed by the series circuit 30 and the converter 20 connected thereto, which during its operation, i.e. due to operation, generates a time-varying voltage between the reference potential BP and, for example, the Figure 1 second module pole 52, which can be used as the measuring voltage Um.

[0048] In the embodiment according to Figure 1 Thus, permanent monitoring of the insulation 56 of the voltage module 50 can advantageously be achieved by means of the measuring device 100 by continuously evaluating the partial discharge currents Ie during operation of the converter 50, provided they occur or are quantitatively recorded.

[0049] In the case of order 5 according to Figure 1Thus, the converter 20 and the series circuit 30 form a voltage supply device, which in turn, together with the measuring device 100, forms an insulation characterization device 200. The insulation characterization device 200 according to Figure 1 can - due to the time-variable measuring voltage Um continuously provided by the converter 20 during converter operation - carry out permanent monitoring of the insulation 56 by detecting any partial discharge currents Ie that may occur.

[0050] The Figure 2 shows a second embodiment of an arrangement 5 according to the invention, which has an insulation characterization device 200 for detecting the insulation state of the insulation 56 of the voltage module 50.

[0051] In contrast to the insulation characterization device 200 according to Figure 1 the insulation characterization device 200 according to Figure 2its own or additional voltage source 210 with internal resistance 211, which is electrically connected between one of the module poles, for example as shown in the Figure 2 shown, the second module pole 52 and the module housing 53 are connected and generate a measuring voltage Um2 for the partial discharge measurement. The measuring voltage Um2 is preferably sinusoidal and preferably has an amplitude of at least 500 V.

[0052] The measuring voltage Um2 can, with a corresponding level and a corresponding time course, also lead to partial discharge currents Ie, which in turn are detected by the measuring device 100, which, together with the isolating capacitance Cm, is located between the second module pole 52 and the reference potential BP.

[0053] In the embodiment according to the Figure 2Partial discharge measurements can also be carried out without active operation of the converter 20 because the necessary measuring voltage can be provided by the additional voltage source 210.

[0054] Furthermore, the above statements apply in connection with the embodiment according to Figure 1 in the embodiment according to Figure 2 accordingly.

[0055] The Figure 3 shows a third embodiment of an arrangement 5 according to the invention. Specifically, the Figure 3 the insulation monitoring device 200 of the second embodiment according to Figure 2 in an arrangement 5 that does not include a converter 20 and a DC / DC converter 40. The measurement voltage Um, which can cause partial discharge currents Ie in the event of insufficient insulation 56 between the module poles 51 and 52 of the voltage module 50, is provided solely by the voltage source 210 of the insulation characterization device 200.

[0056] The measuring device 100 detects any partial discharge currents Ie that may occur and, if necessary, generates a warning signal WS, as described in connection with the Figures 1 and 2 explained above; in this respect, the above statements apply to the embodiment according to Figure 3 accordingly.

[0057] The insulation characterization device 200 according to Figure 3 can be used independently of a vehicle, for example after the voltage module 50 has been manufactured and before it is used within a vehicle.

[0058] The Figure 4 shows a fourth embodiment of an arrangement according to the invention 5. Order 5 according to Figure 4has an insulation resistance measuring device 300 that measures the ohmic resistance of the insulation 56 of the voltage module 50 and generates an alarm signal SA when the ohmic resistance falls below a lower resistance threshold. The electrical connection of the insulation resistance measuring device 300 is not shown in detail for reasons of clarity; the insulation resistance measuring device 300 can, for example, be connected between any of the two module poles 51, 52 and the housing 53.

[0059] The insulation characterization device 200 as described above in connection with the Figures 1 to 3has been described by way of example or at least parts thereof, such as the measuring device 100, are advantageously integrated in the insulation resistance measuring device 300, for example - depending on the embodiment variant - as a submodule, in particular a software-implemented submodule, and optionally generates the warning signal WS described above if partial discharges exceeding a predetermined level are detected.

[0060] The insulation resistance measuring device 300 with the insulation characterization device 200 integrated therein can be installed within the housing 53 of the voltage module 50, as shown in the Figure 4 shown, or arranged outside the housing 53 of the voltage module 50.

[0061] In the embodiments according to the Figures 1 and 2The intermediate circuit capacitance Cz and the series circuit 30 are shown as separate components between the converter 20 and the DC / DC converter 40. Alternatively, the elements can also be integrated within the converter 20 and / or within the DC / DC converter 40. For example, it can be provided that the intermediate circuit capacitance Cz is assigned to the converter 20 and the series circuit 30 is integrated into the DC / DC converter 40.

[0062] The measuring device 100, the coupling unit 110 and the isolation capacitance Cm of the insulation characterization device 200 are in the embodiments according to Figure 1 and 2 shown as separate components. Alternatively, these components can also be integrated within the DC / DC converter 40 or within the voltage module 50. tTime UdcDC voltage UmMeasurement voltage Um2Measurement voltage WSWarning signal Z1first partial impedance Z2second partial impedance

Claims

1. Arrangement (5) with a voltage module (50), which comprises at least one battery (55) and / or at least one fuel cell, wherein both module poles (51, 52) of the voltage module (50) are insulated with respect to a module housing (53) of the voltage module (50) by means of an insulation (56), and with an insulation characterisation facility (200), which comprises at least one voltage provisioning facility and a measuring facility (100), characterised in that - the at least one voltage provisioning facility is suited to applying a temporally variable measuring voltage (Um), in particular a sinusoidal or rectangular alternating voltage, to the insulation (56), and - the measuring facility (100) is designed to capture developing partial discharge currents (Ie) which flow through the insulation (56) and on the basis of the captured partial discharge currents (Ie) to generate a measuring result which characterises the insulation (56).

2. Arrangement (5) according to claim 1, characterised in that the module housing (53) is connected to a reference potential (BP) and a series circuit (30) is connected to at least one of the module poles (51, 52), said series circuit comprising a first partial impedance (Z1), a second partial impedance (Z2) and a centre connection between the partial impedances (Z1, Z2) and the centre connection of which is connected to the reference potential (BP).

3. Arrangement (5) according to claim 2, characterised in that the at least one voltage provisioning facility or at least one of the voltage provisioning facilities of the insulation characterisation facility (200) comprises the first and / or second partial impedance (Z1, Z2).

4. Arrangement (5) according to claim 2 or 3, characterised in that the at least one voltage provisioning facility comprises a converter (20) connected to the series circuit (30), which, on account of its operation, generates a temporally varying voltage with respect to the reference potential (BP) and functions as the or one of the voltage provisioning facilities.

5. Arrangement (5) according to one of the preceding claims, characterised in that the at least one voltage provisioning facility comprises an additional voltage source (210), which is connected electrically between one of the module poles (51, 52) and the module housing (53) and / or in parallel with the first or the second partial impedance (Z1, Z2).

6. Arrangement (5) according to one of the preceding claims, characterised in that the measuring facility (100) is connected electrically between one of the module poles (51, 52) and the module housing (53) and / or electrically in parallel with the first or second partial impedance (Z1, Z2).

7. Arrangement (5) according to claim 5, characterised in that the measuring facility (100) and the voltage source (210) are connected electrically in parallel, wherein both are connected in each case between one of the module poles (51, 52) and the module housing (53) and / or electrically in parallel with the first or second partial impedance (Z1, Z2).

8. Arrangement (5) according to one of claims 4 to 7, characterised in that - the converter (20) connects the voltage module (50) to a drive motor, - wherein the converter (20) comprises a single-phase or multiphase alternating voltage side (AS), which is connected to the drive motor, and a direct voltage side (GS), which is connected to the voltage module (50).

9. Arrangement (5) according to one of claims 4 to 8, characterised in that a DC / DC actuator (40) is connected between the voltage module (50) and the converter (20).

10. Arrangement (5) according to one of the preceding claims, characterised in that the measuring facility (100) generates a warning signal (WS) or a warning message as a measuring result, which indicates an inadequate insulation (56), if the captured partial discharge currents (Ie) lie above a predetermined current threshold and / or indicate discharges above a predetermined discharge threshold.

11. Arrangement (5) according to one of the preceding claims, characterised in that the measuring facility (100) and a separation capacitance (Cm) are connected in series.

12. Arrangement (5) according to one of the preceding claims, characterised in that the voltage module (50) comprises a fuel cell, which is connected in parallel with the module poles (51, 52) directly or by way of a module-internal DC / DC actuator (40).

13. Vehicle, in particular rail vehicle, characterised in that the vehicle comprises an arrangement (5) according to one of the preceding claims.

14. Method for checking an insulation (56) of a voltage module (50), which comprises at least one battery (55) and / or at least one fuel cell, wherein both module poles (51, 52) are insulated with respect to a module housing (53) of the voltage module (50) by means of the insulation (56), characterised in that - with a voltage provisioning facility, a temporally variable measuring voltage (Um), in particular a sinusoidal or rectangular alternating voltage, is applied to the insulation (56), and - developing partial discharge currents (Ie), which flow through the insulation (56), are captured and a measuring result characterising the insulation (56) is generated on the basis of the captured partial discharge currents (Ie).

15. Method according to claim 14, characterised in that the method is carried out during an operation of a vehicle, in particular a rail vehicle, in order to check the insulation (56) of the voltage module (50).