Method for insulation monitoring for an electrically operable vehicle
Patent Information
- Application Number
- EP2023739142
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-06-30
- Filing Date
- 2023-06-28
- Publication Date
- 2025-04-16
Smart Images
Figure 1.1
Abstract
Description
[0001] Description
[0002] Method for insulation monitoring for an electrically operated vehicle
[0003] The invention relates to a method for insulation monitoring for an electrically operated vehicle, wherein the vehicle has a first plurality of insulation monitors and a second plurality of insulation levels, wherein an insulation level each comprises at least one power electronic component and / or a current-carrying component, and wherein an insulation measurement is carried out on at least one insulation level of the second plurality by at least one insulation monitor of the first plurality.
[0004] In electrically operated vehicles, and particularly in vehicles designed for operation on electrified roads, power electronic components and control electronics components are often arranged on different insulation levels, which are individually insulated. To monitor the insulation levels, several monitoring devices, so-called insulation monitors, are usually installed in such a vehicle. An insulation monitor applies a test voltage to the relevant insulation level for an insulation measurement.
[0005] However, if there are multiple insulation levels in a vehicle, the effective ranges of the individual insulation monitors and thus the assigned insulation levels may overlap if, for example, they have more than one connection to an insulation monitor. These insulation monitors are assigned, for example, to a main battery, a DC converter (or DC / DC controller), different isolating ground layers or (in overhead line-operated vehicles) also to a pantograph (or current collector) as corresponding insulation levels or circuits. Additional insulation levels can be provided in particular by other elements in the vehicle's traction circuit.In the case of successive (or even simultaneous) insulation measurements by at least two insulation monitors without sufficient time interval for potential equalization after the test voltage is applied, the individual measurements can influence each other, which can lead to malfunctions in the insulation monitors and thus to errors in the insulation monitoring. Depending on the set repetition frequency of the insulation measurements of the insulation monitors connected to an insulation level, the said errors or malfunctions can occur more or less frequently. In this case, the insulation monitors at interfaces between original components of the vehicle and third-party components from other manufacturers (such as current collectors) are particularly susceptible to failure, not least due to their possible assignment to correspondingly different control units.
[0006] Incorrect measurement results, known as "fault positives," can result. The presence of such a false positive insulation fault has a negative impact on the availability of the vehicle, which can often no longer be operated as a result of the error message, even though the registered error is merely due to a disturbance in the insulation measurement as described above, and could therefore continue to be operated safely.
[0007] The invention is therefore based on the object of specifying a method by means of which insulation measurements can be carried out in an electrically operated vehicle with several insulation levels which are as free from interference as possible.
[0008] The stated object is achieved according to the invention by a method for insulation monitoring for an electrically operated vehicle, which has a first plurality of insulation monitors and a second plurality of insulation levels, wherein an insulation level each comprises at least one power electronic component and / or one current-carrying component, and wherein for a first time interval an inhibition signal is output to a first subgroup of the first plurality, which subgroup comprises at least one first insulation monitor, by a central control unit of the vehicle, which is set up in particular for central control of insulation measurements of the insulation levels.
[0009] According to the method, as a result of the inhibition signal, insulation measurements by the insulation monitor(s) of the first subgroup are completely omitted during the first time interval, and that during the first time interval, an insulation measurement is carried out at least temporarily on at least one insulation level of the second plurality by at least one second insulation monitor, which is not part of the first subgroup. Advantageous and, in part, inventive embodiments are the subject of the dependent claims and the following description.
[0010] An electrically operated vehicle includes, in particular, a purely electrically powered vehicle, but also a hybrid vehicle that additionally has an internal combustion engine and / or a fuel cell. The electrical energy for the electrical operation of the vehicle can be provided, in particular, by an overhead line and / or at least partially by a battery.
[0011] Insulation monitoring includes, in particular, the monitoring of an insulation state of the insulation level in question, for example based on an insulation resistance, which is preferably determined based on a test voltage applied to the insulation level in question.
[0012] The vehicle has a first plurality of insulation monitors, each of which is configured to carry out an insulation measurement and / or to measure an insulation state and in particular an insulation resistance for a defined area of a circuit in the vehicle, preferably for an insulation level.
[0013] The vehicle also has a second plurality of insulation levels, each insulation level comprising at least one power electronic component and / or a current-carrying component, in particular of the traction circuit, and / or a ground component. Such a power electronic component can be provided, for example, by a battery (as the main power source or as a power buffer), or a DC-DC converter; a current-carrying component can also be provided, in particular, by a current collector. A ground component can be provided, in particular, by a metallic component in the vehicle, such as a vehicle frame or the like. The second plurality can be different or identical to the first plurality.
[0014] The central control unit can in particular be provided by a central control unit for all essential vehicle functions of the vehicle, i.e. the vehicle has a central control unit for controlling the essential functions and in particular the drive function, which then also outputs the inhibition signal of the method. However, the central control unit can also be provided by a control unit dedicated to the method, so that it only plays a central role within the scope of the method according to the invention, while the other essential vehicle functions (in particular driving functions) are controlled by another control unit or other control units.
[0015] For a first time interval, the central control unit outputs the inhibition signal for a first subgroup of the first plurality, preferably via one or more appropriately suitable and configured interfaces, so that the inhibition signal is output to at least one first subgroup of the first plurality. The first subgroup has at least one first insulation monitor and can also have additional insulation monitors or can be closed off by the first insulation monitor.
[0016] The inhibition signal preferably represents a negated permission, i.e. a prohibition for the insulation monitor(s) of the first subgroup to carry out an insulation measurement during the first time interval for which the inhibition signal is output. As a result of the inhibition signal, the insulation measurements for the insulation monitors of the first subgroup are thus completely omitted during the first time interval. This omission can in particular be implemented by individual control units which are "upstream" of the individual insulation monitors and which generally control the respective insulation measurement of the respective insulation monitor at an insulation level (or at its components). The control units of the individual insulation monitors can each be connected to the central control unit via corresponding interfaces to transmit the inhibition signal.
[0017] Due to the "prohibition" in the form of the inhibition signal for the insulation monitors of the assigned first subgroup to carry out an insulation measurement, the insulation measurement is therefore omitted during the first time interval in the individual insulation levels which are monitored by the insulation monitors of the first subgroup.
[0018] This omission of other insulation measurements triggered by the inhibition signal can now be used to ensure that a second insulation monitor, which is not part of the first sub-group and is therefore not prevented from carrying out an insulation measurement as a result of the inhibition signal, carries out exactly such a measurement, at least temporarily during the first time interval. The first sub-group is preferably to be coordinated with the second insulation monitor in such a way that the first sub-group comprises those insulation monitors which are most likely to influence the second insulation monitor in the case of simultaneous or rapidly successive insulation measurements (for example as a result of a lack of potential equalization between the insulation levels which are respectively assigned to the insulation monitors in question).the insulation level assigned to the second insulation monitor is assigned to adjacent insulation levels.
[0019] Because the insulation measurement by the second insulation monitor at the insulation level assigned to it is now not disturbed or influenced by insulation monitors on the adjacent insulation levels, the reliability of the insulation measurement can be improved and, in particular, a false positive rate (for example, due to a fall below minimum resistance values) can be reduced, so that unjustified breakdowns of the vehicle fleet can be significantly limited.
[0020] Preferably, as a result of the inhibition signal, an insulation measurement already in progress by the first insulation monitor at an associated insulation level of the second plurality is interrupted. In other words, the inhibition signal results in not only no new insulation measurements being started by the insulation monitors of the first subgroup during the first time interval, but also an insulation measurement already in progress being interrupted or aborted for a respective insulation monitor. Preferably, in this case, any insulation measurement of the first subgroup of insulation monitors is aborted. The abort can be implemented, for example, by individual control units of the respective insulation monitors. By immediately aborting ongoing insulation measurements, uniform conditions with regard to potential equalization can be ensured.
[0021] In an advantageous development, after the end of the inhibition signal, an insulation measurement is resumed by the first insulation monitor at the assigned insulation level. This means in particular that an initially ongoing insulation measurement by the first insulation monitor, which was interrupted as a result of the inhibition signal at the start of the first time interval, is continued or restarted after the end of the first time interval and thus after the end of the inhibition signal. In particular, an insulation measurement can be specified as the "default" state in or for a control unit of the respective insulation monitor, so that this measurement is always carried out when no inhibition signal is being received from the central control unit (via the corresponding interface).
[0022] Preferably, a monitoring voltage is applied to the insulation level for the insulation measurement. This means, in particular, that the monitoring voltage is applied to the corresponding component(s) of the insulation level (e.g., relative to ground or another reference potential). Depending on the design of the insulation monitor and the components of the insulation level, the monitoring voltage can typically be a few tens of V to a few hundred thousand V. This allows the ohmic resistance or voltage drop to be determined, and thus, based on deviations from nominal or theoretically determined values, a reduced insulation resistance can be detected.
[0023] The first time interval is preferably selected as a function of a time for potential equalization which takes place after the monitoring voltage is applied, and / or as a function of a minimum measuring duration for the power electronic or current-carrying component of the insulation level, and / or as a function of a maximum permissible duration without insulation testing for the individual insulation levels of the first plurality and in particular of the first sub-group. In particular, the first time interval is therefore selected to be at least long enough for potential equalization to be possible for the relative configuration of the insulation monitors of the first sub-group before the second insulation monitor starts its insulation measurement at the insulation level in question, and in addition the minimum measuring duration for a component of the insulation level to be monitored by the second insulation monitor is observed.On the other hand, the first time interval is preferably short enough that a new insulation measurement can be carried out on the components of the insulation levels which are monitored by the insulation monitors of the first subgroup in good time after the end of the first time interval, without exceeding the permissible maximum durations for a time without insulation measurement.
[0024] Advantageously, the inhibition signal is output via a communication interface and / or to a control unit, which is / are each assigned to an insulation monitor of the first subgroup. This includes, in particular, that the inhibition signal can be output by the central control unit directly to the individual insulation monitors with appropriate interconnection, or that a communication interface, in particular also at the individual insulation level, forwards the inhibition signal directly to the relevant insulation monitor or its control unit.
[0025] Preferably, the inhibition signal is monitored in the control unit assigned to the respective insulation monitor of the first subgroup. In particular, the said control unit controls the cessation of insulation measurement during the first time interval as a result of the inhibition signal or the resumption of insulation measurement accordingly. This separation of the control of the insulation measurements of an insulation level into the actual insulation monitor and a control unit connected upstream of it further reduces the susceptibility of the insulation measurements to interference.
[0026] Advantageously, the inhibition signal is transmitted via a vehicle's CAN bus, in particular from the vehicle's central control unit to the respective insulation monitor, or at least indirectly to the associated control unit. The advantage of using a CAN bus is its availability in almost all modern vehicles. Furthermore, due to its functionality, the inhibition signal can be output via the CAN bus in such a way that the central control unit can implement it particularly easily, for example within the framework of the J1939 protocol as a character string "01", while the other character strings "00, 10, 11" have a significantly reduced error probability due to the combination of two bits. This also reduces ferry service downtimes due to errors in insulation measurements and corresponding measures.
[0027] It proves to be further advantageous if, after the end of the first time interval, an inhibition signal is successively output by the central control unit of the vehicle for further time intervals to correspondingly assigned, further subgroups of the first plurality, wherein, as a result of the inhibition signal, insulation measurements by the insulation monitor(s) of the respective subgroup are completely omitted during a respective time interval, and wherein, at least temporarily, an insulation measurement is carried out on at least one insulation level of the second plurality by an insulation monitor which is not contained in the respective subgroup during the respective time interval.
[0028] In other words, this particularly includes dividing the first plurality of insulation monitors into different subgroups, which may also partially overlap, although preferably there is no complete overlap between two subgroups. Corresponding inhibition signals are then successively output to the insulation monitors of individual such subgroups, so that an insulation measurement can be carried out by the insulation monitors outside the relevant subgroup for the respective time interval of the respective inhibition signal. Thus, by selecting the said subgroups accordingly, individual insulation levels that are critical for operation can be successively checked by corresponding insulation monitors.
[0029] Advantageously, a monitoring interval is defined for at least some, preferably for each, insulation monitor of the first plurality through a periodic sequence of said time intervals and corresponding insulation measurements, or the omission of such measurements, in the assigned subgroups. This monitoring interval is determined in particular by the period during which the specified insulation monitor does not perform an insulation measurement. Thus, by appropriately coordinating the monitoring intervals, individual insulation levels can be checked using the present method without safety limits being exceeded or undershot.
[0030] Preferably, the periodic sequence of said time intervals for the assigned subgroups is selected such that an insulation level classified as safety-critical has a shorter monitoring interval than an insulation level not classified as safety-critical. An insulation level can be classified as safety-critical in particular if, for example, there is a higher risk of contact or a higher risk of a first fault for the relevant components of the insulation level.
[0031] Advantageously, the periodic sequence of said time intervals for the assigned subgroups is selected depending on an operating mode and / or operating information of the vehicle. In particular, this can be done differently for different insulation levels, resulting in correspondingly different monitoring intervals. An operating mode can be defined, for example, as travel along an overhead line or a door being open for passengers to board and alight while the vehicle remains connected to the overhead line. In this case, more frequent insulation measurements of the insulation level in question can be carried out, particularly for insulation levels in the door area.In particular, operating information may include a vehicle speed, so that the insulation properties of certain components, particularly in the traction circuit, and the associated insulation levels are checked more frequently.
[0032] The invention further relates to an electrically operable vehicle, comprising: a first plurality of insulation monitors, a second plurality of insulation levels, wherein an insulation level each comprises at least one power electronic component and / or one current-carrying component, and a central control unit, wherein the vehicle is set up to carry out the method described above.
[0033] The vehicle according to the invention shares the advantages of the method according to the invention. The advantages stated for the method and its further developments can be applied analogously to the electrically operated vehicle.
[0034] An exemplary embodiment of the invention is explained in more detail below with reference to the accompanying drawings. These show schematically:
[0035] FIG 1 shows a side view of an electrically operated vehicle, and
[0036] FIG 2 shows in a block diagram the sequence of a method for insulation monitoring for the vehicle according to FIG 1
[0037] Corresponding parts and sizes are provided with the same reference numerals in all figures. FIG. 1 shows a schematic side view of an electrically operated vehicle 1, which in the present case is designed as a trolleybus 2. Other designs, for example as a tram or another vehicle, in particular one powered by an overhead line, are also conceivable. The vehicle can also have an internal combustion engine or the like (not shown) as an alternative or for emergencies. The vehicle 1 is supplied with electrical power for electrical operation via an overhead line 4.For this purpose, the vehicle 1 has a current collector 6 (often also referred to as a pantograph), which during operation and in particular during ferry operation is pressed against the overhead line 4 by a spring mechanism (not shown in detail), so that an electrical contact is established between the current collector 6 and the overhead line 4 and thus the transmission of electrical power to the vehicle 1 is made possible. In the present exemplary embodiment, the current collector 6 is electrically connected to a first DC-DC converter 10 arranged in the vehicle 1 (in the presently assumed case of a DC voltage in the overhead line 4; in the not shown case of an AC voltage in the overhead line 4, a rectifier is used instead).
[0038] The first DC-DC converter 10 is electrically connected to a plurality of electric motors 12, each of which is arranged on a wheel 14 (or an axle) of the vehicle 1 and drives the respective wheel 14 (or the respective axle). To this end, the first DC-DC converter 10 brings a DC supply voltage applied to the overhead line 4 to a desired or optimal operating voltage for the respective electric motor 12. In this case, it is possible for each wheel 14 of the vehicle 1 to have its own dedicated electric motor 12, or for individual groups of wheels 14 (for example the wheels of the same respective axle, or of several axles via a transmission) to be driven by an electric motor 12, or for individual wheels 4 not to be driven by an electric motor 12. The electric motors 12 are the primary consumers of the electrical power provided in the vehicle 1 via the overhead line 4.
[0039] Furthermore, the vehicle 1 also has a plurality of secondary consumers 16, which include, by way of example and without being exhaustive, a fan 18 for cooling the power electronic components, a temperature control system 20 (which includes a heating and air conditioning system not shown in detail), lighting 22 and on-board electronics 24, the latter comprising in particular the automatic control and regulation of the electric motors 12 and the electronics for processing control commands for controlling the vehicle 1 by a driver. The secondary consumers 16 are likewise electrically connected to the first DC-DC converter 10 and draw their power from it.In this case, additional DC-DC converters can be connected upstream of individual secondary consumers 16 in order to adjust the voltage output by the first DC-DC converter 10, which is designed for operating the electric motors 12, to the operating voltage of the respective secondary consumer 16. However, this is shown schematically in Figure 1 only for the on-board electronics 24, which is preceded by a second DC-DC converter 26, wherein any further DC-DC converters assigned to the secondary consumers 16 are not shown.
[0040] The first DC-DC converter 10 also supplies power to a battery 28 of the vehicle 1. The battery 28 is designed and configured to supply power to the electric motors 12 in the event of a failure of the external power supply (e.g., due to an externally caused voltage drop or power failure in the overhead line 4).
[0041] For safe operation of vehicle 1, the electric motors 12 as primary loads, the first DC-DC converter 10, the individual secondary loads 16 (as well as the second DC-DC converter 26), and the battery 28 are each assigned to individual insulation levels 30a to 30i, which are intended to ensure the electrical insulation of the respective components of the insulation level from other components, away from the technically intended power flow. The introduction of the separate insulation levels 30a to 30i serves, among other purposes, to ensure that no danger to persons occurs in the event of possible faults, such as galvanic connections to power-carrying components.
[0042] In order to ensure said insulation, and in particular to avoid falling below a minimum resistance of the individual insulation levels 30a to 30i, individual insulation monitors 32a to 32i are provided on these, which are each provided by measuring devices for the said resistance, and carry out insulation measurements on the respective insulation levels 30a to 30i by applying a test voltage, in other words a monitoring voltage.
[0043] It may be that, for technical reasons (particularly temporary or switchable, or even permanent), a specific one of the insulation monitors 32a to 32i has to check two of the insulation levels 30a to 30i (not shown). Moreover, the described insulation measurements on individual insulation levels 30a to 30i (particularly on directly "adjacent" ones) can influence each other due to incomplete potential equalization of the test voltages applied to the individual levels, as a result of which individual insulation measurements may incorrectly measure too low a resistance and thus inadequate insulation for their insulation level 30a to 30i. As a result, vehicle 1 can be temporarily stopped or even taken out of service as a result of a safety measure imposed due to the erroneously unfavorable insulation measurement, even though this would actually not be necessary for technical reasons.
[0044] FIG. 2 therefore shows a schematic block diagram of the sequence of a method for insulation monitoring for the vehicle 1 according to FIG. 1. The vehicle 1 has a plurality of insulation levels 30a to 30i, each of which is assigned an insulation monitor 32a to 32i, and is provided and set up to carry out an insulation measurement at the respective insulation level 30a to 30i by applying an appropriate test voltage. In order to prevent the described mutual influence of the various insulation measurements, a central control unit 34 of the vehicle 1 outputs an inhibition signal II (dashed line) to a first subgroup Gl of the insulation monitors 32a to 32i via appropriate communication interfaces 36a to 36i during a first time interval ATI. The said communication interfaces 36a to 36i can be designed as part of the CAN bus.
[0045] A first insulation monitor 32a from the first subgroup Gl performs an insulation measurement Ma at the assigned insulation level 30a (dashed-dotted line) until the beginning of the first time interval ATI. Further insulation monitors 32c to 32i of the first subgroup Gl can also perform a corresponding insulation measurement (not shown) at the relevant insulation level 30c to 30i at the beginning of the first time interval ATI. The inhibition signal II is not received directly by the first insulation monitor 32a, but by a control unit 38a, which is assigned to the first insulation monitor 32a and controls its insulation measurements.
[0046] Upon receipt of the inhibition signal II via the communication interface 36a, the control unit 38a interrupts the insulation measurement Ma of the first insulation monitor 32a. A similar situation applies to all other insulation monitors 32c to 32i of the first subgroup Gl, or to their control units 38a, 38c-38i, so that the 32c to 32i of the first subgroup Gl stop all insulation measurements (not shown) at the beginning of the first time interval ATI.
[0047] After a short equalization time Ta for the potential equalization of the test voltages of the insulation measurements just performed, a second insulation monitor 32b, which is not part of the first subgroup Gl, now starts an insulation measurement Mb at the insulation level 30b assigned to it by applying a test voltage (dashed line).
[0048] Because in particular the insulation monitors 32a, 32c of adjacent (i.e. potentially suitable for leakage or leakage currents) insulation levels 30a, 30c now do not carry out any insulation measurement, the insulation measurement Mb of the second insulation monitor 32b can be carried out without influencing the insulation measurement Ma (and possibly other insulation measurements of the insulation monitors 32c to 32i of the first subgroup Gl), also as a result of the potential equalization during the equalization time Ta. At the end of the first time interval ATI, the insulation monitors 32a, 32c to 32i also suspend the inhibition signal II for the first subgroup Gl. However, during a second time interval ΔT2, an inhibition signal 12 (dotted line) is now output in an analogous manner by the central control unit 34 to a second subgroup G2 of the insulation monitors 32b to 32i (orto the assigned control devices 38b to 38i), so that no insulation measurement is performed on the corresponding insulation levels 30b to 30i by the said insulation monitors 32b to 32i of the second subgroup G2 during this second time interval AT2. After a short equalization time Tb for potential equalization, an insulation measurement can now be performed on the assigned insulation level using the corresponding test voltage by those insulation monitors that are not part of the second subgroup G2. In particular, the first insulation monitor 32a can thus resume the insulation measurement Ma on the insulation level 30a (not shown).
[0049] Using this procedure, successive insulation measurements can be performed at all insulation levels 30a to 30i, with individual subgroups of these insulation levels being formed in such a way that the insulation monitors remaining outside the respective subgroup can perform their insulation measurements without being influenced by other insulation monitors. In other words, the subgroups are configured such that, for a specific insulation monitor that is to perform an insulation measurement at a specific time interval, all other insulation monitors that could influence said specific insulation monitor during the insulation measurement are defined as part of the assigned subgroup and thus do not perform any insulation measurements due to the inhibition signal.
[0050] Through a sequence of inhibition signals and corresponding time intervals without insulation measurement, as well as by assigning a specific insulation monitor to different subgroups of insulation monitors, each of which receives an inhibition signal and therefore does not perform any insulation measurement, a monitoring interval (not shown) can be defined for each individual insulation monitor as the entire period in which no insulation measurement is performed by the respective insulation monitor. These monitoring intervals can also be specified for the definition of the time intervals and the associated subgroups of insulation monitors, each of which should receive an inhibition signal.The specification can be made dynamically, for example depending on a driving speed, or whether a door of the vehicle is open (in this case the monitoring interval for insulation levels which include components in the vicinity of the door should preferably be reduced), or whether a component is generally safety-critical (here too the monitoring interval for the associated insulation level should preferably be selected to be shorter than for insulation levels of non-safety-critical components).
[0051] Although the invention has been illustrated and described in detail by the preferred embodiment, the invention is not limited by the disclosed examples and other variations may be derived therefrom by those skilled in the art without departing from the scope of the invention. List of Reference Symbols
[0052] 1 (electrically powered) vehicle
[0053] 2 trolleybuses
[0054] 4 Overhead line
[0055] 6 pantographs
[0056] 10 first DC-DC converter
[0057] 12 electric motor
[0058] 14 wheels
[0059] 16 secondary consumers
[0060] 18 fans
[0061] 20 Temperature control
[0062] 22 Lighting
[0063] 24 On-board electronics
[0064] 26 second DC-DC converter
[0065] 28 Battery
[0066] 30a-30i insulation level
[0067] 32a-32i insulation monitor
[0068] 32a, 32b first or second insulation monitor
[0069] 34 central control unit
[0070] 36a-36i communication interface
[0071] 38a-38i control unit
[0072] Gl, G2 first or second subgroup
[0073] II, 12 Inhibition signal
[0074] Ma, Mb insulation measurement
[0075] Ta, Tb compensation time
[0076] ATI first time interval
[0077] ET2 second time interval
Claims
Patent claims 1. A method for insulation monitoring for an electrically operated vehicle (1), wherein the vehicle (1) has a first plurality of insulation monitors (32a-32i) and a second plurality of insulation levels (30a-30i), wherein each insulation level (30a-30i) comprises at least one power electronic component and / or a current-carrying component and / or a ground component, wherein, for a first time interval (ATI), a central control unit (34) of the vehicle (1) outputs an inhibition signal (II) to a first subgroup (Gl) of the first plurality, which comprises at least one first insulation monitor (32a), wherein, as a result of the inhibition signal (II), insulation measurements (Ma) by the insulation monitor(s) (32a, 32c-32i) of the first subgroup (Gl) are completely omitted during the first time interval (ATI),and wherein during the first time interval (ATI) an insulation measurement (Mb) is carried out at least temporarily on at least one insulation level (30b) of the second plurality by at least one second insulation monitor (32b) which is not part of the first subgroup (Gl).
2. Method according to claim 1, wherein as a result of the inhibition signal (II) an already running insulation measurement (Ma) of the first insulation monitor (32a) at an associated insulation level (30a) of the second plurality is interrupted.
3. Method according to claim 1 or claim 2, wherein after the end of the inhibition signal (II) an insulation measurement (Ma) is resumed by the first insulation monitor (32a) at the associated insulation level (30a).
4. Method according to one of the preceding claims, whereby a monitoring voltage is applied to the insulation level (30a-30i) for the insulation measurement (Ma, Mb).
5. The method according to claim 4, wherein the first time interval (ATI) is selected as a function of a time for potential equalization which takes place after application of the monitoring voltage, and / or a minimum measurement duration for the power electronic or current-carrying component of the insulation level (30a-30i), and / or a maximum permissible duration without insulation measurement for the individual insulation levels (30a-30i) of the first plurality.
6. Method according to one of the preceding claims, wherein the inhibition signal (II) is output via a communication interface (36a-36i) and / or to a control unit (38a, 38c-38i), which is / are each assigned to an insulation monitor (30a, 30c-30i) of the first subgroup (Gl).
7. The method according to claim 6, wherein the inhibition signal (II) is monitored in the control device (30a, 30c-30i) assigned to the respective insulation monitor (30a, 30c-30i) of the first subgroup (Gl).
8. The method according to claim 6 or claim 7, wherein the inhibition signal (II) is transmitted via a CAN bus of the vehicle (1).
9. Method according to one of the preceding claims, wherein after the end of the first time interval (ATI) for further time intervals (AT2) by the central control unit (34) of the vehicle (1) successively outputs an inhibition signal (12) to correspondingly assigned, further subgroups (G2) of the first plurality, wherein, as a result of the inhibition signal (12), insulation measurements (Mb) by the insulation monitor(s) (32b) of the respective subgroup (G2) are completely omitted during a respective time interval (ÄT2), and wherein, at least temporarily, an insulation measurement (Ma) is carried out on at least one insulation level (30a) of the second plurality by an insulation monitor (32a) which is not contained in the respective subgroup (G2) during the respective time interval (ÄT2).
10. The method according to claim 9, wherein a monitoring interval is defined by a periodic sequence of said time intervals (ATI, AT2) and corresponding insulation measurements (Ml, Mb) or the omission thereof in the assigned subgroups (Gl, G2) for at least some insulation monitors (32a-32i) of the first plurality.
11. The method according to claim 10, wherein the periodic sequence of said time intervals for the assigned subgroups is selected such that an isolation level (30a-30i) classified as safety-critical has a shorter monitoring interval than an isolation level (30a-30i) not classified as safety-critical.
12. Method according to claim 10 or claim 11, wherein the periodic sequence of said time intervals for the associated subgroups (Gl, G2) is selected as a function of an operating mode and / or operating information of the vehicle (1).
13. Electrically operable vehicle (1), comprising: a first plurality of insulation monitors (32a-32i), a second plurality of insulation levels (30a-30i), wherein an insulation level (30a-30i) comprises at least one power electronic component and / or one current-carrying component, and a central control unit (34), wherein the vehicle (1) is configured to carry out the method according to one of the preceding claims.