Method for detecting a voltage type, and controller

Abstract

The invention relates to a method for detecting a voltage type (100) of a charging voltage provided for a motor vehicle (1). The method comprises the following steps: (i) ascertaining a plurality of voltage values (106) between two electrical conductors of a charging device during a predefined time window (108); (ii) determining (S4) a plurality of evaluation variables on the basis of the plurality of voltage values (106), the plurality of evaluation variables comprising a number of zero crossings, a minimum voltage value and a maximum voltage value during the predefined time window (108); (iii) checking (S6, S8, S10) an evaluation criterion which takes into account the plurality of evaluation variables, the evaluation criterion being suitable for detecting the voltage type (100) of the charging voltage. The invention further relates to a corresponding controller and to a computer program.

Description

[0001] DESCRIPTION

[0002] DESIGNATION

[0003] Method for detecting a voltage type and control unit

[0004] TECHNICAL AREA

[0005] The present disclosure relates to methods for detecting a voltage type of a charging voltage intended for a motor vehicle and to corresponding control units.

[0006] BACKGROUND OF THE INVENTION

[0007] Electric vehicles typically have separate charging ports for direct current (DC) and alternating current (AC) charging, as is the case with the widely used Combined Charging System (CCS) or the CHAdeMO system, which is designed for DC only. Newer types of charging connectors, such as those based on the North American Charging Standard (NACS), can transmit both DC and AC current through the same contacts. Therefore, the vehicle must be able to distinguish between DC and AC current and adapt the charging circuitry for charging the vehicle battery depending on the voltage type.

[0008] SUMMARY AND FORMS OF EXECUTION

[0009] It is therefore an objective of the present disclosure to provide a method and a corresponding control unit with which a voltage type of a charging voltage connected to a motor vehicle can be reliably identified with minimal effort.

[0010] This task is accomplished by a method for detecting a voltage type, by a control unit, and by a computer program according to the independent patent claims. Advantageous embodiments and further developments are described in the respective dependent claims, the following description, and the drawings.

[0011] Thus, according to a first aspect, a method for detecting the voltage type of a charging voltage intended for a motor vehicle is provided. The method comprises the following steps: (a) determining, for example by measuring, a plurality of voltage values ​​between two electrical conductors of a charging device during a specified time window; (b) determining a plurality of evaluation parameters based on the plurality of voltage values, wherein the plurality of evaluation parameters includes a number of zero crossings, a minimum voltage value, and a maximum voltage value during the specified time window; (c) verifying an evaluation criterion that considers the plurality of evaluation parameters, wherein the evaluation criterion is suitable for detecting the voltage type of the charging voltage.

[0012] In the context of this disclosure, a charging device is defined, for example, as any device suitable for electrically charging a vehicle battery, or a part thereof. A charging device may, for example, be a charging connector, in particular a charging plug or socket, or a vehicle-side charging circuit.

[0013] In the context of this disclosure, an electrical conductor is defined, for example, as an electrically conductive connection or part of such a connection. An electrical conductor can, for example, be an electrical contact that enables a detachable electrical connection, such as a contact of a charging plug or charging socket. Alternatively, an electrical conductor can, for example, be an electrical connection of a vehicle-side charging circuit. This electrical connection can be electrically connected to an electrical contact of a vehicle charging socket. In the context of this disclosure, a battery is defined, for example, as a storage device for electrical energy, particularly on an electrochemical basis. In one embodiment, the battery is an accumulator, i.e., a rechargeable battery. The battery can be recharged via the charging device by means of the electrical conductors.The battery can be a traction battery, which is suitable for providing energy to a vehicle's drive system. The battery can be a high-voltage battery.

[0014] In the context of this disclosure, the majority of voltage values ​​can be positive, negative, or zero. Similarly, the minimum and maximum voltage values ​​can also be positive, negative, or zero. However, the signal width, i.e., the difference between the maximum and minimum voltage values, is always positive or zero.

[0015] In the context of this disclosure, a voltage type is defined, for example, based on a voltage waveform. Voltage types can therefore be distinguished by their waveform shape, such as periodic or constant, and / or by their magnitude, such as maximum amplitude, signal width, or mean value of the waveform. Voltage types can be determined via corresponding current types and vice versa. For example, an alternating current corresponds to a corresponding alternating voltage and a direct current corresponds to a corresponding direct voltage.

[0016] In the context of this disclosure, an evaluation criterion is defined, for example, based on one or more conditions. Depending on which of these conditions are met, the stress type can be determined using the evaluation criterion.

[0017] The described method and the corresponding control unit can be advantageous for reliably detecting the voltage type of a charging voltage intended for a motor vehicle using simple means. This can mitigate or even completely prevent damage to the battery or electronics if an unsuitable voltage type is connected. Furthermore, in vehicles that can be charged with different voltage types, the charging circuit can be adapted to the detected voltage type.

[0018] Reliable voltage type detection is particularly relevant for newer charging devices that use the same connectors for both AC and DC charging, with the vehicle's charging circuitry being adapted to the voltage type. Consequently, with such charging devices, there is a particularly high risk of incompatibility between the voltage type and the vehicle's charging mode, for example, when charging with AC in DC mode or with DC in AC mode. In such a case, the hardware can be switched accordingly based on the detected voltage type.

[0019] Because readily available evaluation parameters such as the number of zero crossings, the maximum voltage, and the minimum voltage during a time window are used, a fast, simple, and reliable identification of the voltage type is possible. These parameters can be analyzed without particular difficulty; complex algorithms such as spectral analysis are not required. Furthermore, no additional hardware is needed for voltage determination.

[0020] Due to the simple evaluation, only low demands are placed on computing power and storage capacity, so that the approach can be implemented flexibly, for example in a battery management system, an engine control unit or a smart connector.

[0021] According to one embodiment, the two electrical conductors are two contacts of a charging connector, for example, a vehicle charging socket. The two contacts can, for example, be contacts of different phase conductors or one contact of a phase conductor and one contact of a neutral conductor. Additional voltage values ​​between more than two contacts can also be determined and analyzed. According to one embodiment, the voltage type of the charging voltage is detected based on the evaluation criterion.

[0022] According to one embodiment, the voltage type is detected from a plurality of possible voltage types, wherein the plurality of possible voltage types includes positive DC voltage, negative DC voltage, and AC voltage. In particular, a distinction between negative and positive DC voltage can be advantageous because incorrect polarity can cause significant damage to the battery or electronics, especially in the high-voltage range.

[0023] According to one embodiment, if no voltage type from the majority of possible voltage types is detected, an invalid voltage type is detected. Such an embodiment can be advantageous for taking special safety precautions in the event of an invalid voltage signal, thereby mitigating or even preventing damage.

[0024] According to one embodiment, a signal width or peak-to-peak voltage is determined based on the minimum and maximum voltage values, whereby the detection of a DC voltage within the evaluation criterion requires that the signal width be smaller than a predefined signal width threshold. The signal width can, for example, be defined as the difference between the maximum and minimum voltage values. Such an embodiment can be advantageous for reliably distinguishing between DC and AC voltage. A narrow signal width is typically expected with DC voltage, which can be primarily caused by disturbances or fluctuations in the voltage signal.

[0025] According to one embodiment, detecting a positive DC voltage within the evaluation criterion requires that the maximum voltage value and / or the minimum voltage value be greater than a predefined positive voltage threshold, and / or detecting a negative DC voltage within the evaluation criterion requires that the minimum voltage value and / or the maximum voltage value be less than a predefined negative voltage threshold. Such an embodiment can be advantageous because thresholds ensure simple yet robust evaluation. Distinguishing between negative and positive DC voltage prevents damage caused by incorrect polarity.

[0026] According to one embodiment, the specified signal width threshold, the specified further signal width threshold, the specified negative voltage threshold and / or the specified positive voltage threshold are specified depending on the smallest DC charging voltage and / or the smallest AC charging voltage supported by the motor vehicle or its charging infrastructure.

[0027] For example, the respective threshold values ​​can be chosen to be at least five percent, and in particular at least ten percent, smaller than the corresponding values ​​of the respective lowest supported charging voltage. For example, the positive voltage threshold can be chosen to be the corresponding percentage smaller than the lowest supported DC charging voltage. The voltage range threshold can be chosen to be the corresponding percentage smaller than the voltage range of the lowest supported AC charging voltage.

[0028] Such an embodiment can be advantageous because the same limit values ​​are used for different orders of magnitude of the charging voltage, thus making the method particularly simple. Furthermore, uncertainties or fluctuations in the voltage measurement, which typically have a magnitude of approximately one percent, can be taken into account.

[0029] According to one embodiment, the specified

[0030] The positive voltage threshold and the specified negative voltage threshold are defined in terms of their magnitude. Although negative and positive charging voltages are typically of the same order of magnitude, this allows for the consideration of disturbance types that affect positive and negative voltages differently, such as high-frequency disturbances in the power grid. In an alternative configuration, the positive voltage threshold and the negative voltage threshold are equal in magnitude.

[0031] According to one embodiment, detecting an alternating voltage within the evaluation criterion requires that the number of zero crossings exceeds a predefined zero-crossing threshold and that the signal width exceeds a predefined secondary signal width threshold. In one further embodiment, the predefined secondary signal width threshold is equal to the predefined signal width threshold. However, these thresholds can also differ. Such an embodiment can be advantageous because redundancy in the queried conditions enables particularly robust and reliable detection of an alternating voltage. Accordingly, a direct current voltage could be ruled out based solely on the number of zero crossings, even without considering the signal width as an additional condition.

[0032] According to one embodiment, a zero crossing is detected if successive voltage values ​​of the majority of voltage values ​​have different signs.

[0033] According to one embodiment, the predetermined zero-crossing threshold is selected depending on the duration of the time window, for example, depending on the number of expected zero crossings during the time window at a frequency of the charging AC voltages supported by the motor vehicle.

[0034] According to one embodiment, detecting the alternating voltage within the evaluation criterion requires that a maximum voltage value is greater than a predefined additional positive voltage threshold and / or that a minimum voltage value is less than a predefined additional negative voltage threshold. In one embodiment, these additional thresholds correspond to the respective thresholds already introduced above. In other words, the additional positive voltage threshold can be the same as the positive voltage threshold and / or the additional negative voltage threshold can be the same as the negative voltage threshold. However, the thresholds can also differ. Such an embodiment can be particularly advantageous in combination with the previous embodiment because additional parameters are taken into account, so that, due to the redundancy in the conditions, the determined result is more reliable and robust.

[0035] According to one embodiment, a zero crossing is detected if a first voltage value and a second voltage value of the plurality of voltage values ​​lie on opposite sides outside a fluctuation band, wherein the fluctuation band includes the voltage zero and wherein all voltage values ​​of the plurality of voltage values ​​that lie in time between the first and the second voltage values ​​lie within the fluctuation band. The width of the fluctuation band can, for example, be greater than 5 V, and in particular greater than 10 V. For example, the fluctuation band can include all voltages between -5 V and +5 V. Thus, if the first voltage value is +6 V and the second voltage value is -7 V, and all voltage values ​​in between lie between -5 V and +5 V, a zero crossing would be detected.

[0036] Such an embodiment can be advantageous because small disturbances around the zero value of the voltage are not interpreted as zero crossings, which could, for example, lead to the incorrect detection of an alternating voltage.

[0037] According to one embodiment, voltage values ​​with a frequency of at least 100 Hertz are determined as the majority of voltage values. The voltage values ​​can be determined discretely or continuously. Such an embodiment can be advantageous for reliably detecting zero crossings and maximum or minimum values, particularly in power grids with typical frequencies of 50 or 60 Hertz. Frequencies of at least 100 Hertz can be advantageous with regard to the Nyquist-Shannon sampling theorem to obtain reliable results. According to one embodiment, the frequency is greater than 200 Hertz, particularly greater than 400 Hertz, for example, approximately 500 Hertz. Such frequencies can be advantageous for determining minimum values, maximum values, or the signal width with particular accuracy.

[0038] According to one embodiment, the voltage values ​​of the majority of voltage values ​​are sampled equidistantly in terms of time.

[0039] According to one embodiment, the duration of the predetermined time window or sampling window is less than 1 s, in particular less than 500 ms. The duration of the time window can be greater than 50 ms, in particular greater than 100 ms. According to one embodiment, the predetermined time window is at least as long as one period of an AC voltage signal supported by the vehicle. Such an embodiment can be advantageous because, on the one hand, the voltage type is determined in a short time, and on the other hand, a reliable result is ensured by analyzing several periods.

[0040] According to one embodiment, the method further comprises at least one of the following steps: (i) adapting a charging circuit in the motor vehicle to the detected voltage type, if the detected voltage type is supported by the motor vehicle; (ii) implementing a hardware protection measure if the detected voltage type is not supported by the motor vehicle or if an invalid voltage type has been detected. A possible hardware protection measure could be, for example, disconnecting the battery and / or a charging circuit from the vehicle's charging contacts.

[0041] According to a further aspect, a procedure is provided which comprises the following steps: (a) evaluating a plurality of conditions, which includes at least one of the following: determining that the voltage signal is valid, or receiving a trigger signal, wherein the trigger signal specifically indicates that a charging cable plug is inserted; (b) if the plurality of conditions is satisfied, carrying out a procedure as described above.

[0042] According to one embodiment, the method is executed repeatedly or continuously as long as the trigger signal is received, in particular as long as the plug is inserted.

[0043] According to another aspect, a control unit is provided which is set up to carry out the procedure described above.

[0044] According to one embodiment, the control unit is integrated into a charging cable, a charging plug, and / or a charging socket. For example, the control unit is integrated into a smart connector. Alternatively, the control unit can also be integrated into the vehicle itself.

[0045] According to another aspect, a computer program is provided which includes instructions that, when executed by a computer, cause it to carry out the previously described procedure. In the context of the present disclosure, a computer is defined, for example, as a device that processes data using programmable computational instructions. Computers can be embedded in everyday devices, such as in the control units of motor vehicles.

[0046] According to another aspect, a storage medium is provided with a computer program, wherein the computer program includes instructions which, when executed by a computer, cause it to carry out the procedure described above.

[0047] BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Further advantages and beneficial designs and developments of the method, the control unit, and the computer program will become apparent from the following exemplary embodiments illustrated in conjunction with the figures. These show:

[0049] Figure 1 shows different voltage types that can be detected using a voltage type detection method according to an embodiment of the present disclosure;

[0050] Figure 2 shows a method for detecting a voltage type of a charging voltage intended for a motor vehicle according to an embodiment of the present disclosure.

[0051] Identical, similar, or similarly effective elements are marked with the same reference symbols in the figures. In some figures, individual reference symbols have been omitted for clarity. The figures and the relative sizes of the elements depicted within them are not to be considered to scale. Rather, individual elements may be exaggerated for better representation and / or comprehensibility.

[0052] DETAILED DESCRIPTION OF EXAMPLES OF EXECUTION

[0053] Figure 1 shows, in its upper part, examples of different voltage types 100: first an alternating voltage, then a positive direct voltage, a negative direct voltage, and finally an invalid voltage type. These voltage types 100 are represented by measured voltage values ​​106 in a graph of the voltage 105 over time 107.

[0054] The lower part of Figure 1 shows, using the same time scale 107, how the different voltage types 100 are detected by a voltage determination method after a respective time window 108 (debouncing time), in the same sequence: first the alternating voltage 101, then the positive direct voltage 102, the negative direct voltage 103, and finally the invalid voltage type 104. Figure 2 shows a method for detecting a voltage type 100 of a charging voltage intended for a motor vehicle.The method comprises the following steps: (i) determining a plurality of voltage values ​​106 between two electrical conductors of a charging device during a specified time window 108; (ii) determining S4 a plurality of evaluation parameters based on the plurality of voltage values ​​106, wherein the plurality of evaluation parameters includes: a number of zero crossings, a minimum voltage value, a maximum voltage value, each during the specified time window 108, and the difference between the maximum and minimum voltage values; (iii) verifying S6, S8, S10 an evaluation criterion that considers the plurality of evaluation parameters, wherein the evaluation criterion is suitable for detecting the voltage type of the charging voltage.

[0055] More precisely, in the first step S1, conditions for determining the voltage type are evaluated; for example, a trigger signal indicating whether a charging plug is inserted is examined. In the next step S2, it is evaluated whether an activation condition for determining the voltage type is met. If this is not the case, voltage determination is omitted in step S3. If, however, the activation condition is met, voltage values ​​are determined in steps S4 and S5 until the end of a time window (debouncing time) is reached. In step S4, the following evaluation parameters are determined for all voltage values ​​obtained so far: number of zero crossings, maximum voltage value, minimum voltage value, and signal width (peak-to-peak voltage), i.e., the difference between the maximum and minimum voltage values.The voltage values, and consequently the maximum and minimum voltage values, can be positive, negative, or zero. As long as the time window has not ended, step S4 is repeated according to step S5. The last determined evaluation parameters are used to determine the voltage type after the time window has expired.

[0056] In steps S6, S8, and S10, various conditions are checked as part of an evaluation criterion. In step S6, it is examined whether the maximum voltage value is greater than a positive voltage threshold and the signal width is less than a signal width threshold. If both conditions are met, a positive DC voltage is determined as the result in step S7. However, if at least one condition is not met, a further condition is examined in step S8, namely whether the minimum voltage value is less than a negative voltage threshold. If this is the case, and the signal width is also less than the signal width threshold, then a negative DC voltage is determined as the result in step S9. If, however, at least one of the conditions from step S8 is not met, three conditions are examined in step S10.First, as in step S6, it is checked whether the maximum voltage value is greater than the positive voltage threshold. Second, it is checked whether the signal width is greater than the signal width threshold. Third, it is checked whether the number of zero crossings is greater than a zero crossing threshold. If all three conditions are met, an AC voltage is determined as the result in step S11. Otherwise, no valid voltage type is determined as the result, according to step S12.

[0057] Depending on the result, further measures are taken, for example, hardware such as a charging circuit can be switched, a diagnostic message can be issued, or component protection measures can be implemented.

[0058] The invention is not limited to the exemplary embodiments described therein. Rather, the invention encompasses every new feature and every combination of features, which in particular includes every combination of features in the exemplary embodiments and claims. REFERENCE MARK

[0059] 100 voltage type

[0060] 101 Alternating current

[0061] 102 positive DC voltage 103 negative DC voltage

[0062] 104 Invalid voltage type

[0063] 105 Voltage

[0064] 106 voltage values

[0065] 107 Time 108 Time window

Claims

PATENT CLAIMS 1. Method for detecting a voltage type (100) of a charging voltage intended for a motor vehicle, the method comprising the following steps: Determining a plurality of voltage values ​​(106) between two electrical conductors of a charging device during a specified time window (108); Determine (S4) a plurality of evaluation variables based on the plurality of voltage values ​​(106), wherein the plurality of evaluation variables includes a number of zero crossings, a minimum voltage value and a maximum voltage value during the specified time window (108); Check (S6, S8, S10) an evaluation criterion which takes into account the majority of evaluation variables, wherein the evaluation criterion is suitable to detect the voltage type (100) of the charging voltage.

2. Method according to the preceding claim, wherein the voltage type (100) is detected from a plurality of possible voltage types (101 , 102, 103), wherein the plurality of possible voltage types comprises a positive DC voltage (102), a negative DC voltage (103) and an AC voltage (101 ).

3. Method according to the preceding claim, wherein if no voltage type (100) of the plurality of possible voltage types (101 , 102 , 103) is detected, an invalid voltage type (104) is detected.

4. Method according to one of the preceding claims, wherein a signal width is determined based on the minimum voltage value and the maximum voltage value, and wherein the detection (S7, S9) of a DC voltage within the scope of the evaluation criterion (S6, S8) requires that the signal width is less than a predetermined signal width threshold.

5. Method according to the preceding claim, wherein the detection (S7) of a positive DC voltage within the scope of the evaluation criterion (S6) requires that the maximum voltage value is greater than a predetermined positive voltage threshold, and / or wherein the detection (S9) of a negative DC voltage within the scope of the evaluation criterion (S8) requires that the minimum voltage value is less than a predetermined negative voltage threshold.

6. Method according to the preceding claim, wherein the predetermined signal width threshold, the predetermined negative voltage threshold and the predetermined positive voltage threshold are predetermined as a function of the smallest DC charging voltage supported by the motor vehicle and / or the smallest AC charging voltage supported by the motor vehicle.

7. Method according to claim 5 or 6, wherein the predetermined positive voltage threshold and the predetermined negative voltage threshold differ in magnitude.

8. Method according to one of the preceding claims, wherein the detection (S11 ) of an alternating voltage within the scope of the evaluation criterion (510) presupposes that a number of zero crossings is greater than a specified zero crossing threshold and that a signal width is greater than a specified further signal width threshold.

9. Method according to the preceding claim, wherein the detecting (511 ) of the alternating voltage within the framework of the evaluation criterion (S10) requires that a maximum voltage value is greater than a specified further positive voltage threshold and / or that a minimum voltage value is less than a specified further negative voltage threshold.

10. Method according to one of the preceding claims, wherein a zero crossing is detected if a first voltage value and a second The stress value of the plurality of stress values ​​(106) on opposite sides lies outside a fluctuation band, wherein the fluctuation band includes the stress zero, and wherein all stress values ​​of the plurality of stress values ​​(106) that are between the first and the second stress value in time lie within the fluctuation band.

11. Method according to one of the preceding claims, wherein voltage values ​​with a frequency of at least 100 Hertz are determined as the plurality of voltage values ​​(106).

12. A method according to any of the preceding claims, further comprising at least one of the following steps: - Adapting a charging circuit in the motor vehicle to the detected voltage type, if the detected voltage type (S7, S9, S11) is supported by the motor vehicle; - Implement a hardware protection measure if the detected voltage type (S7, S9, S11) is not supported by the vehicle or if an invalid voltage type (S12) has been detected.

13. Control unit which is configured to carry out a method according to one of the preceding claims.

14. Control unit according to the preceding claim, wherein the control unit is integrated into a charging cable, a charging plug and / or a charging socket.

15. Computer program comprising instructions which, when executed by a computer, cause the computer to perform a method according to any one of claims 1 to 12.

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