System for a vehicle, component, and method for detecting the connection state of a switching device of a charging circuit

Abstract

A system (12) for a vehicle, an assembly (10), and a method for detecting a connection state of a switching device (62) of a charging circuit (56) are provided. The system (12) comprises at least one stator coil (30) of an electric machine (18), an inverter (16), and a charging circuit (56). The inverter (16) is configured to be coupled to a battery (14) of the vehicle. The charging circuit (56) is configured to be coupled to a charging device external to the vehicle. The charging circuit (56) is further configured for adapting a charging program of the battery (14) of the vehicle. The charging circuit (56) comprises at least a capacitor (64) and the switching device (62). The switching device (62) is arranged between the capacitor (64) and the stator coil (30). A single voltage sensing element (66) is arranged between the switching device (62) of the charging circuit (56) and a star point (60) of the electric machine (18). A control circuit (36) is configured to detect the connection state of the switching device (62) of the charging circuit (56) based on a voltage magnitude measured by the voltage sensing element (66).

Description

[0001] The present invention relates to a system for a vehicle, a component, and a method for detecting the connection status of a switching device for a charging circuit.

[0002] The batteries of hybrid and electric vehicles can typically be charged via external resources, such as external charging devices. According to some methods, charging circuits are known that provide selective connection, allowing specific charging paths to be enabled and disabled as needed. These charging circuits include switching devices for implementing selective connection. Because high charging currents are transmitted via the switching devices, the proper operation of the switching devices must be checked periodically, such as after each charging cycle.

[0003] US2019 / 0353708 A1 discloses a system with a charging circuit. Proper operation of the switching device is controlled by two voltage sensing circuits arranged and configured to detect voltage amplitudes on opposite sides of the switching device. These multiple voltage sensing circuits result in a complex topology with a large number of components. Therefore, these systems are inefficient to manufacture.

[0004] Accordingly, a more compact charging topology is needed, which requires fewer components, thereby avoiding cable routing and reducing weight.

[0005] The subject matter of the independent claims satisfies the corresponding needs. Additional embodiments are indicated in the dependent claims and the following description, each of which may individually or in combination represent aspects of the invention.

[0006] According to one aspect, a system for a vehicle is provided. The system includes at least one stator coil of a motor, an inverter, and a charging circuit. The inverter is configured to be connected to a vehicle battery. The charging circuit is configured to be connected to a charging device external to the vehicle. The charging circuit is also configured to adapt to a charging procedure for the vehicle battery. The charging circuit includes at least a capacitor and a switching device. The switching device is arranged between the capacitor and the stator coil. A single voltage sensing element is arranged between the switching device of the charging circuit and the star point of the motor. A control circuit is configured to detect the connection state of the switching device of the charging circuit based on a voltage value measured by the voltage sensing element.

[0007] This invention is based on the discovery that a single voltage sensing element is sufficient to reliably detect the connection state of a switching device. This is made possible because a specific test signal can be applied to test the connection state of the switching device. Thus, a single voltage sensing device can be used to detect the response based on the test signal. This response can be evaluated, thereby reliably determining the connection state of the switching device.

[0008] Therefore, compared to existing methods, fewer components are required to assess whether the switching device operates correctly as expected. In other words, a single voltage sensing element is sufficient to reduce the need for cabling and thus reduce weight and manufacturing costs.

[0009] Preferably, the connection state of the switching device involves either non-conductive or conductive. In the non-conductive state, the switching device is open. In the conductive state, the switching device may be closed or even welded.

[0010] Whether the switching device is operating normally can be determined (based on control signals applied to the switching device by the control circuit to ensure that the switching device should have a specific connection state). In other words, the control circuit can be configured to adapt the connection state of the switching device to the charging circuit. Accordingly, the control circuit can compare the desired connection state of the switching device with the results of an evaluation based on a voltage sensing element.

[0011] In some respects, the system can be configured to boost the voltage supplied to the battery by the charging device. This is made possible because specific charging paths can be selectively implemented based on switching devices to allow the charging process to occur. For example, the star connection of the motor can be connected to an external charging device, enabling a higher total charging rate (amount charged per unit time).

[0012] Optionally, the inverter includes multiple switching devices. The control circuitry is configured to control these multiple switching devices such that predefined voltage pulses are provided jointly by them. These voltage pulses can be specifically considered as reference signals that propagate toward the voltage sensing element depending on the connection state of the switching devices. Therefore, by using a single voltage sensing element to measure the voltage magnitude, the connection state of the switching devices can be reliably determined with high accuracy.

[0013] More specifically, the voltage magnitude, measured by a single voltage sensing element and caused by the impedance of system components, can indicate the specific voltage drop time behavior after a specific voltage pulse has been generated. In this respect, the time behavior of the voltage drop is affected by the connection state of the switching device. Therefore, by evaluating the measured voltage magnitude, the control device can accurately determine the connection state of the switching device.

[0014] In some embodiments, the control circuitry may include a pulse width modulator (PWM) configured to provide control signals to the gate drivers of a plurality of switching devices of the inverter, such that the output signals of the plurality of switching devices of the inverter are adaptable. The PWM can be used to define corresponding connection states of the plurality of switching devices of the inverter. This enables the generation of specific voltage pulses, such as voltage pulses having specific voltage magnitudes or including specific timing characteristics (e.g., regarding the pulse's time period). In other words, based on the PWM, a specific control program can be executed to generate a specific reference signal (voltage pulse).

[0015] In one aspect, the control circuit can be configured to determine the time constant of the voltage drop detected based on multiple detected voltage values. Based on these multiple detected voltage values, the temporal behavior of the voltage value can be evaluated after a specific voltage pulse is generated. Since the connection state of the switching device in the charging circuit affects the temporal behavior, different time constants will occur depending on whether the switching device is open (non-conducting) or closed (conducting).

[0016] Preferably, the control circuit can be configured to determine that the switching device of the charging circuit is disconnected (non-conductive) if the determined time constant is lower than a first time constant threshold.

[0017] Alternatively or cumulatively, the control circuit may be configured to determine that the switching device of the charging circuit is closed (conduction / welding) if the determined time constant exceeds a second time constant threshold.

[0018] In some embodiments, the first time constant threshold and the second time constant threshold can be the same. In this case, the evaluation procedure is compact.

[0019] In an alternative approach, the first time constant threshold and the second time constant threshold can be different. Preferably, the second time constant threshold can be greater than the first time constant threshold. In this case, a lag is provided, allowing for the avoidance of volatile evaluation procedures.

[0020] According to one aspect, the stator may include multiple stator coils interconnected at a star point. A switching device may be arranged between the star point and a charging unit terminal configured to be connected to a charging device. In this respect, the charging unit terminal may be part of an on-board charging circuit or a DC / DC converter, which may be directly or more precisely indirectly connected to an external charging device.

[0021] Preferably, the switching device of the charging circuit is a relay or a transistor.

[0022] Alternatively, the motor is a synchronous motor, such as an electrically excited synchronous motor. The motor can be any motor used in traction applications.

[0023] According to one aspect, a component is provided. This component includes the system described above and a vehicle battery. Based on this system, the battery can be charged at a lower voltage via charging unit terminals. However, the proper operation of the switching device of the charging circuit can be reliably evaluated.

[0024] According to another aspect, a method is provided for detecting the connection state of a switching device in a charging circuit. The charging circuit is configured to adapt a charging procedure for a vehicle's battery based on the connection between the charging circuit and a charging device external to the vehicle. The charging circuit includes at least a capacitor and a switching device. The switching device is arranged between the vehicle's capacitor and at least one stator coil of a motor. An inverter is connected to at least one stator coil of the motor. The method includes at least the following steps:

[0025] - The control circuit outputs a first control signal. Based on the control signal, the switching device of the charging circuit should be turned off.

[0026] - The control circuit outputs additional control signals to the inverter's switching devices, so that the switching devices can jointly provide predefined voltage pulses.

[0027] -Disable all switching devices of the inverter based on additional control signals from the control circuit.

[0028] - The voltage value is detected by a single voltage sensing element arranged between the switching device of the charging circuit and the star point of the motor.

[0029] - The control circuit determines the connection state of the switching device of the charging circuit based on the detected voltage value.

[0030] This method offers several advantages already explained above regarding the corresponding system. In short, it provides a specific reference signal based on voltage pulses generated by the inverter's switching devices. Since the charging circuit's switching devices should be open (non-conductive), the detected voltage magnitude can be evaluated based on the voltage pulses. Because the time behavior of the response to the generated voltage pulses depends on the connection state of the charging circuit's switching devices, this connection state can be reliably determined with high accuracy and confidence, despite requiring only a single voltage sensing element. Consequently, compared to prior art methods, this system requires fewer components and demonstrates improved manufacturing and operational efficiency.

[0031] Optionally, after the inverter's switching devices are deactivated and a predefined time period is waited, the voltage value can be detected by a voltage sensing element. In this regard, the control circuit can be configured to initiate a sensing process performed by the voltage sensing element. Alternatively, the voltage sensing element can continuously detect the corresponding voltage value, but the control circuit can ignore the voltage value until the predefined time period expires.

[0032] The connection state of the switching device in the charging circuit affects the temporal behavior following the generation of a voltage pulse. While the difference may be immediately detectable, it causes a divergent signal profile between the states of switching device closure and opening. In other words, the difference between the signal profiles corresponding to switching device closure and opening increases over time, at least for a period of time, which depends particularly on the generated voltage pulse. Therefore, regarding this divergence effect, if an appropriate predefined time period expires after the generation of the voltage pulse, the different signal profiles can be distinguished from each other with high confidence. Of course, the predefined time period is chosen based on the specific system and the generated voltage pulse to ensure that the different signal profiles can be distinguished from each other with high confidence.

[0033] To evaluate the timing behavior, the control circuit can determine the time constant of the voltage drop based on multiple detected values ​​of the voltage magnitude. This time constant is then compared to at least one time constant threshold. Depending on the different connection states of the switching devices in the charging circuit, the time constant threshold can be correlated with a signal having a profile between the distinguishing signal profiles explained above. In other words, the time constant threshold can be selected such that the corresponding signal profile can be considered as a boundary for distinguishing the different connection states of the switching devices in the charging circuit.

[0034] The foregoing aspects and other advantages of the claimed subject matter will become more readily apparent, as these aspects and advantages will be better understood when referred to the following detailed description in conjunction with the accompanying drawings. In the accompanying drawings:

[0035] - Figure 1 This is a schematic diagram of the components according to an embodiment.

[0036] - Figure 2 This is a schematic diagram of a method for detecting the connection state of a switching device in a charging circuit according to an embodiment, and

[0037] - Figure 3 It is a schematic diagram of different profiles of the detected voltage value depending on the connection state of the switching device of the charging circuit.

[0038] All features mentioned below with respect to embodiments and / or drawings may be used alone or in any sub-combination with features of the invention (including preferred features of preferred embodiments).

[0039] Figure 1 This is a schematic diagram of component 10 according to an embodiment. Component 10 includes a system 12 for a vehicle according to an embodiment, and a battery 14 (preferably a high-voltage battery) for the vehicle.

[0040] System 12 includes an inverter 16 and a motor 18. The inverter 16 and the motor 18 can be considered as the drive unit 20 for the vehicle.

[0041] Inverter 16 is generally arranged to provide a power supply signal to motor 18, so that motor 18 can output torque to vehicle components, for example, for driving.

[0042] In the illustrated embodiment, inverter 16 includes a B6 bridge with three half-bridges 22. The following functionality is illustrated with reference to only one half-bridge 22, but applies accordingly to all half-bridges 22 of the B6 bridge.

[0043] Each half-bridge 22 includes a first switching device 24 (e.g., a transistor) that acts as a high-side power switch and a second switching device 26 (e.g., a transistor) that acts as a low-side power switch.

[0044] The transistor can be a metal-oxide-semiconductor field-effect transistor (MOSFET), an insulated-gate bipolar transistor (IGBT), or a silicon carbide or gallium nitride field-effect transistor (SiC or GaN FET).

[0045] Between the first switching device 24 and the second switching device 26, each half-bridge 22 includes a central node 28 for outputting a voltage signal to the stator coil 30 (L2 in this case) of the motor 18.

[0046] Three corresponding current signals L1, L2 and L3 are applied to multiple stator coils 30 of motor 18 via three half-bridges 22, thereby establishing (driving) alternating current in the stator coils 30 of motor 18.

[0047] Unlike the three-phase topology of the motor 18 in this embodiment, other topologies are also possible, which would require corresponding modifications to the inverter 16 (e.g., a six-phase motor 18, a multilevel inverter).

[0048] The corresponding half-bridge 22 is connected to the bus structure 32 of the inverter 16. The inverter 16 is connected to a battery 14 representing a DC power supply. The DC power supply includes terminals between which a high voltage HV with a voltage amplitude of, for example, 100V or greater, particularly 400V or 800V, is provided.

[0049] Additionally, inverter 16 includes a DC link capacitor 34, which acts as a connection element between battery 14 and motor 18. For example, under varying load conditions caused by different torques output by motor 18, DC link capacitor 34 ensures that the power supply signal is more uniform with respect to current and / or voltage amplitudes.

[0050] To control the switching states of switching devices 24 and 26, component 10 includes control circuitry 36. Control circuitry 36 can also be considered as part of drive unit 20 or at least assigned to inverter 16 and / or motor 18. Control circuitry 36 includes at least one data processing circuitry 38.

[0051] The control circuit 36 ​​is configured to provide corresponding control signals G1 and G2 to the switching devices 24 and 26 of the inverter 16, such that the switching positions of the switching devices 24 and 26 are affected by these control signals. The control signals G1 and G2 depend on the modulation signal 40, which is determined by means of the pulse width modulator 42.

[0052] Control signals G1 and G2 are output to gate driver circuits 44, which are connected to the gate electrodes of switching devices 24 and 26. Based on control signals G1 and G2, gate driver circuits 44 generate corresponding gate signals to influence the switching states of switching devices 24 and 26 between closed (conducting) and open (non-conducting).

[0053] To determine the corresponding control signals G1 and G2 and to achieve the desired operation of the motor 18, the control circuit 36 ​​is connected to current sensors 46, which are arranged between the center node 28 of the half-bridge 22 and the stator coil 30 of the motor 18. The current sensors 46 are configured to detect the amplitude of the current output from the half-bridge 22 of the inverter 16 to the motor 18, and in particular the waveform of this current, and to transmit the detected current amplitude value to the control circuit 36.

[0054] The control circuit 36 ​​may be generally connected to other components of the assembly 10. In some embodiments, the control circuit 36 ​​may be connected to the motor 18, and / or to a rotor sensor configured to detect the position of the rotor of the motor 18 relative to the stator, and / or to the battery 14.

[0055] Therefore, control circuit 36 ​​can output corresponding control signals G1, G2, for example, based on the rotor position. Consequently, the stator coils 30 of motor 18 are supplied with corresponding current signals. The precise control of motor 18, and therefore the characteristics of these control signals G1, G2, largely depend on torque request 48 received by control circuit 36 ​​from a higher-level component of the vehicle. Torque request 48 indicates which output torque motor 18 will provide. For example, torque request 48 may depend on the pedal position of the vehicle's pedals.

[0056] During the operation of component 10, the charge level of battery 14 decreases. Therefore, battery 14 needs to be charged from time to time. In this regard, component 10 includes a charging unit terminal 50. The charging unit terminal 50 can be considered as the output of the vehicle's DC / DC converter or on-board charging circuit. Through the charging unit terminal 50, battery 14 can be indirectly connected to an external charging device, such as a charging station, wall-mounted charging box, or power outlet.

[0057] For charging, battery 14 can be connected to charging unit terminal 50 via bus structure 32 (including positive and negative bus) and corresponding groups of switching devices 52, 54 (assigned to charging unit terminal 50 and battery 14). Typically, the individual switching devices of the separate groups of switching devices 52 assigned to charging unit terminal 50 and switching devices 54 assigned to battery 14 are enabled or disabled one group at a time between closing and opening.

[0058] To enable the charging process, component 10 and system 12 additionally include a charging circuit 56 disposed between the charging unit terminal 50 and the motor 18.

[0059] The charging circuit 56 generally provides an additional electrical connection 58 between the charging unit terminal 50 and the star point 60 of the motor 18, at which the stator coils 30 are connected to each other.

[0060] Based on the charging circuit arranged between the switching device 52 (assigned to the charging unit terminal 50) and the star point 60 of the motor 18, the switching device 62 can select between on (closed; enabled) and off (disabled). Specifically, if the group of switching devices 52 assigned to the charging unit terminals 50 are jointly controlled (closing the switching device associated with the star point and the switching device associated with the negative bus and disabling the switching device associated with the positive bus), the charging circuit 56 needs to include an independent switching device 62 to provide the possibility of a controlled activation mechanism for the electrical connection 58 established by the charging circuit 56.

[0061] The connection state of the switching device 62 of the charging circuit 56 is controlled by the control circuit 36 ​​based on the control signal GS.

[0062] The switching device 62 of the charging circuit 56 can be a relay or a transistor.

[0063] The charging circuit 56 also includes a capacitor 64 connected between the electrical connection 58 and the bus structure 32. The capacitor 64 is connected to the input side of the switching device 62 of the charging circuit 56, that is, to the side of the terminal 50 assigned to the charging unit.

[0064] During the charging process used to enhance the charging level of battery 14, a high-amplitude charging current is transmitted across the switching device 62 of charging circuit 56.

[0065] To control the proper operation of the switching device 62 of the charging circuit 56, for example to prevent the charging process from causing the switching device 62 to weld, the system 12 includes a single voltage sensing element 66 connected between the switching device 62 and the star point 60 of the motor 18. The single voltage sensing element 66 is configured to detect the voltage level at the output side of the switching device 62 (i.e., the side of the star point 60 of the motor 18 opposite to the input side of the switching device 62 to which the capacitor 64 of the charging circuit 56 is connected).

[0066] Figure 2 This is a schematic diagram of a method for detecting the connection state of a switching device 62 in a charging circuit 56 according to an embodiment. Optional steps are shown in dashed lines.

[0067] According to step S2, the control circuit 36 ​​outputs a first control signal GS. Based on the first control signal GS, the switching device 62 of the charging circuit 56 should be disconnected (non-conductive).

[0068] In subsequent step S4, control circuit 36 ​​outputs additional control signals G1 and G2 to the switching devices 24 and 26 of inverter 16, causing switching devices 24 and 26 to jointly provide a predefined voltage pulse. It is assumed that the battery 14 is sufficiently charged to generate a voltage pulse. Based on control signals G1 and G2, control circuit 36 ​​can control the switching devices 24 and 26 of inverter 16 so that the generated voltage pulse includes desired characteristics, such as a specific pulse length and a specific voltage amplitude.

[0069] After the voltage pulse is generated, in step S6, all switching devices 24 and 26 of the inverter 16 are deactivated based on control signals G1 and G2 from the control circuit 36. This means that the stator coil 30 of the motor 18 is disconnected from the battery 14.

[0070] According to the subsequent optional step S8, after disabling the switching devices 24 and 26 of inverter 16, a predefined time period is waited for. The predefined time period can be selected to achieve high detection accuracy and confidence, which will be referred to below. Figure 3 Let me explain in more detail.

[0071] According to the next step S10, the voltage value is detected by a single voltage sensing element 66 arranged between the switching device 62 of the charging circuit 56 and the star point 60 of the motor 18. Of course, the single voltage sensing element 66 can continuously detect the corresponding voltage value, and the control circuit 36 ​​simply ignores the detected value to take into account the predefined time period of optional step S8. Alternatively, for example, after the predefined time period expires, the actual detection of the voltage value can be initiated by the control circuit 36.

[0072] In a subsequent optional step S12, the control circuit 36 ​​considers multiple detected voltage values ​​to determine the time constant of the voltage drop that occurs after the voltage pulse is generated. Based on the inherent impedance of system 12, such as the impedance of the stator coil 30 of motor 18, such as the passive discharge resistor of capacitor 64 or the passive discharge resistor of DC link capacitor 34, such as the resistor cascade of voltage sensing element 66, the voltage amplitude caused by the generated voltage pulse decreases within a corresponding time period, thereby establishing a voltage drop that can be detected based on multiple measured voltage values. The time characteristics of the voltage drop (e.g., the time constant) are affected by the connection state of the switching device 62 of charging circuit 56, i.e., by the characteristic of whether the switching device 62 is closed (conducting) or open (non-conducting). This effect is at least partly caused by whether the capacitor 64 of charging circuit 56 is connected to a single voltage sensing element 66 via the switching device 62. Therefore, multiple detected voltage values ​​will cause different time constants of the voltage drop depending on the connection state of the switching device 62.

[0073] In the next optional step S14, the control circuit 36 ​​compares the time constant of the voltage drop determined in optional step S12 with at least one time constant threshold. The time constant threshold is selected accordingly so that the independent connection states of the switching devices 62 of the charging circuit 56 can be distinguished from each other.

[0074] The method further includes step S16, in which the control circuit 36 ​​determines the connection state of the switching device 62 of the charging circuit 56 based on the detected voltage value. For example, an alternative comparison step S14 could be considered in this regard. Alternatively, the detected voltage value could be compared with a voltage value threshold, thus omitting the determination of the time constant. In any case, the connection state of the switching device 62 can be determined between closed (conducting) and open (non-conducting) based on the detected voltage value.

[0075] Figure 3 These are schematic diagrams of different signal profiles 72A and 72B, depending on the connection state of the switching device 62 of the charging circuit 56 and the detected voltage value.

[0076] On the y-axis, the voltage value detected by a single voltage sensing element 66 arranged between the switching device 62 and the star point 60 of the motor 18 is shown as a function of time on the x-axis.

[0077] At time t0, voltage pulses are generated based on control signals G1 and G2 output from control circuit 36 ​​to the switching devices 24 and 26 of inverter 16. Accordingly, the voltage magnitude shows a rise 68 toward the target voltage 70 until time t1 when the switching devices 24 and 26 of the inverter are deactivated (disconnected).

[0078] Subsequently, the generated voltage amplitude decreases, showing a voltage drop from the target voltage 70. Signal profiles 72A and 72B differ from each other depending on the connection state of the switching device 62 of the charging circuit 56. In other words, the characteristics of the voltage drop after the generated voltage pulse differ depending on whether the switching device 62 is on (closed) or off (open). Specifically, if the switching device 62 is off (open), the slope of the resulting signal profile 72A is steeper than the slope of the signal profile 72B corresponding to the switching device 62 being on (closed). Therefore, signal profile 72A corresponds to a smaller time constant than signal profile 72B. Accordingly, the control circuit 36 ​​can determine the time constant based on multiple detected values ​​of the voltage magnitude and compare the determined time constant with a corresponding time constant threshold to distinguish different connection states of the switching device 62.

[0079] Furthermore, the difference between signal profiles 72A and 72B increases over time. Therefore, in an alternative or additional manner, control circuit 36 ​​can wait for a predefined time period Δt until time t2 after disabling switching devices 24 and 26, and distinguish the connection state of switching device 62 of charging circuit 56 based on a single detected value of the voltage magnitude at time t2. Regarding the different slopes of signal profiles 72A and 72B, the different connection states of switching device 62 can be effectively distinguished from each other. Generally, the predefined time period Δt depends on the characteristic properties of system 12 and component 10 and is selected accordingly.

[0080] Component 10, system 12, and method enable reliable determination of the connection state of the switching device 62 of the charging circuit 56 based on a single voltage sensing element 66. Therefore, operational and production efficiency is high.

Claims

1. A system (12) for a vehicle, said system (12) comprising at least one stator coil (30) of a motor (18), an inverter (16), and a charging circuit (56), wherein, The inverter (16) is configured to be connected to the vehicle's battery (14), wherein the charging circuit (56) is configured to be connected to a charging device external to the vehicle, and wherein the charging circuit (56) is further configured to adapt to the charging procedure of the vehicle's battery (14). The charging circuit (56) includes at least a capacitor (64) and a switching device (62), wherein the switching device (62) is arranged between the capacitor (64) and the stator coil (30). A single voltage sensing element (66) is arranged between the switching device (62) of the charging circuit (56) and the star point (60) of the motor (18), and The control circuit (36) is configured to detect the connection state of the switching device (62) of the charging circuit (56) based on the voltage value measured by the voltage sensing element (66).

2. The system (12) as claimed in claim 1, wherein, The inverter (16) includes a plurality of switching devices (24, 26), and wherein the control circuit (36) is configured to control the plurality of switching devices (24, 26) of the inverter (16) such that a predefined voltage pulse is provided by the plurality of switching devices (24, 26) of the inverter (16).

3. The system (12) as described in claim 1 or 2, wherein, The control circuit (36) includes a pulse width modulator (42) configured to provide control signals to the gate driver circuit (44) of a plurality of switching devices (24, 26) of the inverter (16) such that the output signals of the plurality of switching devices (24, 26) of the inverter (16) are adaptable.

4. The system (12) as described in any of the preceding claims, wherein, The control circuit (36) is configured to determine the time constant of the voltage drop detected based on a plurality of detection values ​​of the voltage magnitude.

5. The system (12) as claimed in claim 4, wherein, The control circuit (36) is configured to determine that the switching device (62) of the charging circuit (56) is open if the determined time constant is lower than a first time constant threshold, and / or The control circuit (36) is configured to determine that the switching device (62) of the charging circuit (56) is closed if the determined time constant exceeds the second time constant threshold.

6. The system (12) as described in any of the preceding claims, wherein, The control circuit (36) is configured to adapt to the connection state of the switching device (62) of the charging circuit (56).

7. The system (12) as described in any of the preceding claims, wherein, The stator of the motor (18) includes a plurality of stator coils (30) connected to each other at the star point (60), and The switching device (62) is arranged between the star point (60) and the charging unit terminal (50), which is configured to be connected to the charging device.

8. A component (10) comprising a system (12) according to any one of the preceding claims and a battery (14) of the vehicle.

9. A method for detecting the connection state of a switching device (62) of a charging circuit (56), the charging circuit being configured to adapt a charging procedure for a vehicle's battery (14) based on the connection of the charging circuit (56) to a charging device external to the vehicle. in, The charging circuit (56) includes at least a capacitor (64) and a switching device (62), wherein the switching device (62) is arranged between the capacitor (64) and at least one stator coil (30) of the vehicle's motor (18), wherein an inverter (16) is connected to at least one stator coil (30) of the motor (18). The method includes at least the following steps: - A first control signal is output by the control circuit (36), wherein, based on the control signal, the switching device (62) of the charging circuit (56) should be turned off. - The control circuit (36) outputs additional control signals to the switching devices (24, 26) of the inverter (16), so that the switching devices (24, 26) together provide a predefined voltage pulse. -Based on additional control signals from the control circuit (36), all switching devices (24, 26) of the inverter (16) are disabled. - The voltage value is detected by a single voltage sensing element (66) arranged between the switching device (62) of the charging circuit (56) and the star point (60) of the motor (18), and The control circuit (36) determines the connection state of the switching device (62) of the charging circuit (56) based on the detected voltage value.

10. The method of claim 9, wherein, After a predefined time period is waited after the switching devices (24, 26) of the inverter (16) are deactivated, the voltage value is detected by the voltage sensing element (66).

11. The method of claim 9 or 10, wherein, The control circuit (36) determines a time constant for voltage drop based on multiple detected values ​​of the voltage magnitude, wherein the time constant is compared with at least one time constant threshold.

Images