Method, processor and computer program for diagnosing a voltage sensor in a charging connection of a vehicle, and vehicle

Abstract

The invention relates to a method (200), a processor and a computer program for diagnosing at least one voltage sensor (151, 152, 153) in a charging connection (150) of an (electric) vehicle. The invention makes use of the measure of diagnosing the functionality of mains voltage sensors (151, 152, 153) that monitor the charging connection (150) by comparing the voltage measured thereby with voltages (125, 135) measured on the converter side when a DC voltage from the battery (110) of the vehicle is applied (220) in a targeted manner.

Description

[0001] R.409840

[0002] - 1 -

[0003] Description

[0004] title

[0005] Method, computing unit and computer program for diagnosing a voltage sensor in a vehicle charging port as well as vehicle

[0006] The present invention relates to a method for diagnosing at least one mains voltage sensor in a charging port of a vehicle that is at least partially electrically powered, as well as a computing unit and a computer program for carrying out this method and a vehicle with such a computing unit.

[0007] Background of the invention

[0008] Power grids vary worldwide, characterized by grid voltage, grid frequency, and distribution system. Furthermore, an on-board charger (OBC) for charging the high-voltage battery(ies) of an electric vehicle can be connected to one or more phases if multiple phases are available. The OBC must be compatible with a wide range of grid configurations. For example, in the German distribution system, an OBC can be connected to a single-phase, two-phase, or three-phase supply.

[0009] In order for the OBC software to select the appropriate operating strategy, the current network configuration must typically be detected first. This detection can be achieved, for example, using network voltage sensors.

[0010] To ensure operational reliability, the functionality of these sensors can be verified, for example, through redundant design. R.409840

[0011] - 2 -

[0012] Disclosure of the invention

[0013] According to the invention, a method for diagnosing at least one mains voltage sensor in a charging port of a vehicle that is at least partially electrically powered, as well as a computing unit and a computer program for carrying out this method, and a vehicle with such a computing unit, comprising the features of the independent claims, are proposed. Advantageous embodiments are the subject of the dependent claims and the following description.

[0014] The invention employs a method for diagnosing the functionality of mains voltage sensors in an (electric) vehicle, which monitor a charging port, by comparing the voltage measured by these sensors, when a DC voltage from the vehicle's battery is applied, with voltages measured on the converter side. This eliminates the need for redundant mains voltage sensors compared to conventional solutions, without sacrificing diagnostic capabilities, as the converter-side voltage sensors perform this function. These converter-side voltage sensors are typically already present in both unidirectional and bidirectional converters, so no additional hardware is required.

[0015] In detail, according to the invention, the at least partially electrically driven vehicle comprises at least one mains voltage sensor in a charging port, for example an AC charging port, a battery, a bidirectional DC-DC converter, and a power converter connected between the charging port and the DC-DC converter. An intermediate circuit with a capacitor arrangement and at least one, in particular two, converter-side voltage sensor(s) is provided between the power converter and the DC-DC converter. If two converter-side voltage sensors are provided, it is advantageous to arrange them such that a first of the two converter-side voltage sensors detects a voltage between a first pole and a second pole of the converter and a R.409840

[0016] - 3 - the second of the two converter-side voltage sensors detects a voltage between the first pole and a center tap of the capacitor arrangement.

[0017] Within the scope of this invention, a "power converter" is understood to be a device which is at least equipped to convert an alternating voltage into a direct voltage, and, if desired, vice versa, to convert a direct voltage into an alternating voltage.

[0018] Unless otherwise stated, the terms "connected," "connection," etc., refer to electrically conductive connections. Similarly, the term "current" refers to electric currents.

[0019] The method according to the invention comprises applying at least one predetermined DC voltage to the DC-DC converter using electrical energy from the battery, whereby a measuring voltage can be detected by the at least one converter-side voltage sensor, applying the measuring voltage to the at least one mains voltage sensor using the power converter, and determining the functionality of the at least one mains voltage sensor based on a comparison of the measuring voltage detected by the at least one mains voltage sensor and the measuring voltage detected by the at least one converter-side voltage sensor.

[0020] In at least one embodiment, the at least one DC voltage comprises several DC voltages with different magnitudes, in particular where the several DC voltages are selected from a range between 0 V and a maximum nominal input voltage of the charging port. This allows the functionality of the mains voltage sensor(s) to be diagnosed over a larger, in particular the entire required, operating range.

[0021] The multiple DC voltages can each have the same voltage difference in pairs, i.e., they can be equidistant (R.409840).

[0022] - 4 - to each other. This allows for a uniform diagnostic quality across the entire work area.

[0023] In cases where multiple DC voltages are used, the voltages can be applied sequentially with increasing magnitudes, particularly when different. This charges the capacitors in the capacitor bank step by step. This method is therefore more energy-efficient than alternating charging and discharging processes and also subjects the capacitors to fewer cycles.

[0024] In at least one embodiment, the method further includes preventing the application of an alternating voltage to the charging port until the functionality of at least one mains voltage sensor has been determined. This ensures a defined voltage level and protects the electrical components in the current path from overload, particularly in cases where the mains voltage sensor(s) are not (fully) functional, as in such cases an emergency shutdown of the charging port may not be triggered.

[0025] Alternatively or additionally, the procedure can be suspended if an AC voltage is present at the charging port until no AC voltage is present. In other words, the procedure can include preventing the application of at least one predetermined DC voltage between the first and second terminals of the DC-DC converter using electrical energy from the battery and / or the application of the first and / or second partial voltage to at least one mains-side voltage sensor, depending on an input voltage present at the charging port. Thus, the procedure is only carried out in cases where no external voltage is present at the charging port and may automatically initiate such a state. R.409840

[0026] - 5 -

[0027] A computing unit according to the invention, e.g. a control unit of a motor vehicle, is, in particular in terms of programming, equipped to carry out a method according to the invention.

[0028] A vehicle according to the invention comprises such a computing unit as well as a battery, a charging port with at least one mains voltage sensor, a bidirectional DC-DC converter and a power converter connected between the charging port and the converter, wherein an intermediate circuit with a capacitor arrangement and at least one converter-side voltage sensor is provided between the power converter and the DC-DC converter.

[0029] Implementing a method according to the invention in the form of a computer program or computer program product with program code for carrying out all method steps is also advantageous, as this incurs particularly low costs, especially if an executing control unit is already available for other tasks. Finally, a machine-readable storage medium is provided with a computer program stored on it as described above. Suitable storage media or data carriers for providing the computer program are, in particular, magnetic, optical, and electrical storage media, such as hard drives, flash memory, EEPROMs, DVDs, etc. Downloading a program via computer networks (Internet, intranet, etc.) is also possible. Such a download can be wired or wireless (e.g., via a WLAN network, a 3G, 4G, 5G, or 6G connection, etc.).

[0030] Further advantages and embodiments of the invention will become apparent from the description and the accompanying drawing.

[0031] The invention is schematically illustrated in the drawing using an exemplary embodiment and is described below with reference to the drawing.

[0032] Brief description of the drawings R.409840

[0033] - 6 -

[0034] Figure 1 schematically shows a section of an on-board network of a vehicle according to the invention based on a simplified block diagram.

[0035] Figure 2 schematically shows a method according to the invention using a highly simplified flowchart.

[0036] embodiment(s) of the invention

[0037] Figure 1 schematically shows a simplified block diagram illustrating a section of the electrical system of a vehicle according to the invention, and is designated as 100. In particular, the illustrated section of the electrical system 100 comprises an (on-board) charger and its connection to a vehicle battery.

[0038] The vehicle electrical system 100 includes a battery 110, for example, a high-voltage battery with a nominal voltage of over 100 V, e.g., 800 V. A bidirectional DC-DC converter 120 is connected to the battery 110, with a first terminal 121 and a second terminal 122. In this example, the first terminal 121 is assumed to be the negative terminal and the second terminal 122 the positive terminal. The converter 120 is designed to convert a DC voltage with a voltage different from the battery's nominal voltage into a DC voltage that is essentially equal to the battery's nominal voltage, and conversely, it can also convert the battery's nominal voltage into a voltage that is not equal to the nominal voltage. In other words, the converter can use the battery both as a power source and to charge the battery.

[0039] A power converter 140 is connected to the converter 120, with an intermediate circuit 130 connected between the converter 120 and the power converter 140. The intermediate circuit 130 comprises a capacitor arrangement 132, which here has two capacitors connected in series between the first terminal 121 and the second terminal 122 and a center tap between the two capacitors. A first voltage sensor 125 on the converter side detects a voltage between the first terminal 121 and the second terminal 122.

[0040] - 7 -

[0041] The voltage drop between terminal 121 and the second terminal 122 is detected by a second voltage sensor 135 on the converter side, which detects a voltage drop between the center tap and the first terminal 121, also referred to here as the first partial voltage. In addition to the capacitor arrangement 132, the intermediate circuit 130 in the example shown has two switching elements S17 and S18, which serve in particular to implement a vehicle-to-load operating mode in which an external consumer is supplied with energy from the battery 110.

[0042] A charging port 150 is provided for charging the battery 110. This port is connected to the converter 120 via the power converter 140 and the intermediate circuit 130. In the example shown here, the charging port has an input socket 155 with three phase connections 1, 2, 3, a neutral conductor connection 4, and a protective conductor connection 5. However, other configurations are also possible within the scope of the invention. In particular, the charging port 150 is not necessarily configured as a three-phase connection.

[0043] The charging port 150 also features a sensor arrangement 157 with at least one mains voltage sensor (here, three mains voltage sensors 151, 152, 153), as well as a switch arrangement 159. The sensor arrangement 157 is configured to determine an input voltage for each of the phase connections 1, 2, 3. This allows, in particular, the determination of whether and to which type of charging point (e.g., DC charging point, AC charging point, single-phase, multi-phase, mains voltage, mains frequency, etc.) the charging port is connected. This information is important for charge control, for example, to appropriately control the power converter 140. Using the switch arrangement 159, active phase connections 1, 2, 3 can be connected to corresponding inputs of the power converter 140.The power converter 140 comprises three half-bridges, each having two series-connected semiconductor switches S11, S12; S13, S14; S15, S16 and a center tap between each pair of series-connected semiconductor switches S11, S12; S13, S14 and S15, S16, respectively, wherein each center tap is connected or connectable to one of the phase terminals 1, 2, 3 via the switch arrangement 159. In the example shown here, the neutral terminal 4 of the charging terminal 150 is connected to the center tap of the capacitor arrangement 132, as well as to a center tap of an R.409840.

[0044] - 8 -

[0045] The half-bridge comprises the two series-connected switching elements S17, S18 (e.g., semiconductor switches) of the intermediate circuit 130. In the example shown here, the half-bridge S17, S18, to which the neutral terminal is connected, is assigned to the intermediate circuit 130. However, in embodiments of the invention, it can also be integrated, for example, into the power converter 140.

[0046] As already explained, the sensor arrangement 157 is of central importance for the operation of the charging port 150. Therefore, before or at the start of commissioning the charging port 150 (e.g., starting a charging process), the functionality of the mains voltage sensors 151, 152, 153 must be determined to prevent damage to the vehicle electrical system (in the event of a malfunction). Conventional solutions can, for example, provide a redundant (e.g., duplicate) design of the mains voltage sensors 151, 152, 153. In embodiments of this invention, in particular embodiments of a method according to the invention, as explained below with reference to Figure 2, such a redundant design of the mains voltage sensors 151, 152, 153 can be dispensed with without compromising diagnostic capability.

[0047] Figure 2 schematically illustrates an embodiment of a method according to the invention using a simplified flowchart, and is designated as 200 in its entirety. References to device components within the explanation of method 200 may refer in particular to the electrical system shown in Figure 1. However, it should be expressly emphasized here that method 200 can also be carried out using other suitable electrical systems and is not limited to the specific embodiment of the electrical system 100 described.

[0048] In a first step 210 of the procedure, the vehicle electrical system 100 is put into a charging preparation mode, for example by activating the mains voltage sensors 151, 152, 153 and the converter-side voltage sensors 125, 135 and initializing the components of the vehicle electrical system 100 for communication, e.g. with a control unit. Furthermore, in step 210 a signal can be sent to a charging point outside the vehicle electrical system 100 indicating that no R.409840

[0049] - 9 -

[0050] The charging port 150 may be energized. Alternatively, it can be ensured or prevented in other ways that a voltage is applied to the phase terminals 1, 2, 3 from the outside. For example, applying a voltage to the phase terminals 1, 2, 3 from the outside can also be prevented by locking a charging flap that blocks external access to the charging port 150. Alternatively or additionally, in step 210, it can be checked whether a voltage is present at at least one of the phase terminals 1, 2, 3, and only if no voltage is present can the execution of procedure 200 be continued.

[0051] In step 220, the capacitor arrangement 132 of the intermediate circuit 130 is charged to a first predetermined voltage, whereby the electrical energy required for this is drawn from the battery 110 and converted to the predetermined voltage by means of the converter 120. The predetermined voltage is applied between the first terminal 121 and the second terminal 122 until no current flows. During this charging process 220 with respect to the capacitor arrangement, all switches of the half-bridges of the intermediate circuit 130 and the converter 140 are open.

[0052] Once the capacitor arrangement 132 is fully charged to the first predetermined voltage, the process continues with step 230, in which a first side S12, S14, S16 of the converter's half-bridges is switched to a closed position, either simultaneously or sequentially. This applies the first predetermined voltage to the respective phase terminals 1, 2, 3, with the first partial voltage drop occurring between each phase terminal 1, 2, 3 and the neutral terminal 4. Alternatively, if the switching element S17 is also switched to a closed state, the full predetermined voltage is applied between the neutral terminal 4 and each phase terminal 1, 2, 3.Depending on whether the first partial voltage or the predetermined voltage is applied to the respective phase terminal, in step 230 a phase voltage detected by the respective mains voltage sensor is compared with the measured voltage detected by the first transformer-side voltage sensor 125 or the second transformer-side voltage sensor 135. R.409840.

[0053] - 10 -

[0054] Subsequently, in step 240, the first side S12, S14, S16 of the half-bridges of the converter and, if applicable, the switching element S17 are brought back into an open position, i.e., the phase connections 1, 2, 3 and, if applicable, the neutral conductor connection 4 are disconnected from the voltage supply by means of the converter 120.

[0055] Subsequently, in step 250, a second side S11, S13, S15 of the converter's half-bridges (and, if applicable, the DC link switching element S18) is switched to a closed state, which essentially corresponds to the procedure in step 230, but with a reversal of the predetermined voltage. Also in step 250, the phase voltages detected by the mains voltage sensors 151, 152, 153 are compared with the measured voltages detected by the converter-side voltage sensors 125, 135.

[0056] In step 260, it is determined whether the results of the comparisons from steps 230 and 250 indicate a malfunction of one or more of the mains voltage sensors 151, 152, and 153. This can be the case, for example, if a deviation between the phase voltage detected by the relevant mains voltage sensor 151, 152, or 153 and the measured voltage detected by the respective converter-side voltage sensor 125 or 135 exceeds a predetermined threshold. This threshold can be, for example, an absolute threshold (e.g., 1 V, 5 V, 10 V, ...) or a relative threshold (e.g., 1%, 3%, 10%, ...). In particular, the threshold can be defined within the framework of an application or device testing, thus enabling both robust operation without false diagnoses and robust / reliable diagnostics.

[0057] Furthermore, in the example shown here, step 260 checks whether the first predetermined voltage applied between the first pole 121 and the second pole 122 corresponds to a nominal voltage of the charging terminal 150. If this is not the case, the procedure 200 returns to step 220 to adjust the capacitor arrangement to a further, in particular higher, first voltage.

[0058] - 11 -

[0059] to charge the voltage. Steps 220 to 260 can be repeated, in particular, until the nominal voltage is reached. For example, in each iteration, the initial voltage can be increased by a predetermined amount, e.g., by 10 V, 20 V, 50 V, or by an amount of, for example, 5%, 10%, or 20% of the nominal voltage, or another amount. If it is determined in step 260 that the nominal voltage has been reached, the procedure 200 can be terminated, or the process can continue with step 270, in which the external prevention of applying voltage to phase terminals 1, 2, 3 is stopped. This can be done, for example, by sending an enable signal to a connected charging point or by releasing a lock on the aforementioned charging flap.

[0060] If, in step 260, it is determined that at least one of the mains voltage sensors is malfunctioning, the application of voltage to the relevant phase terminal 151, 152, 153 can be prevented externally, depending particularly on the severity of the malfunction, or the relevant phase terminal 1, 2, 3 can be disconnected from the power converter 140 by means of the switch arrangement 159. A corresponding blocking of the relevant phase terminal can also be communicated to a connected charging point, so that only phase terminals whose voltage sensors are functioning correctly are energized in step 270.

[0061] The step-by-step procedure described here is merely an example. Embodiments of the invention may, for example, perform the specified steps in a partially or completely different, e.g., reversed, order, or carry out individual steps partially or completely simultaneously or in parallel with each other.

Claims

R.409840 - 12 - Claims 1. Method (200) for diagnosing at least one mains voltage sensor (151, 152, 153) in a charging port (150) of a vehicle that is at least partially electrically powered, wherein the vehicle comprises a battery (110), a bidirectional DC-DC converter (120) and a power converter (140) connected between the charging port (150) and the converter (120), wherein an intermediate circuit (130) with a capacitor arrangement (132) and at least one converter-side voltage sensor (125, 135) is provided between the power converter (140) and the DC-DC converter (120), wherein the method (200) comprises: Applying (220), using electrical energy from the battery (110), at least one predetermined DC voltage to the DC-DC converter (120), whereby a measuring voltage can be detected by the at least one converter-side voltage sensor (125, 135), supplying (230, 250), using the power converter (140), the at least one mains voltage sensor (151, 152, 153) with the measuring voltage, and Determine (260) the functionality of the at least one mains voltage sensor (151, 152, 153) on the basis of a comparison of the measured voltage detected by the at least one mains voltage sensor (151, 152, 153) and the measured voltage detected by the at least one converter-side voltage sensor (125, 135).

2. Method (200) according to claim 1, wherein the at least one predeterminable DC voltage comprises several DC voltages with different magnitudes. R.409840 - 13 - 3. Method (200) according to claim 2, wherein the multiple DC voltages are selected from a range between 0 V and a nominal input voltage of the charging port (150).

4. Method (200) according to claim 2 or 3, wherein the multiple DC voltages have an equal voltage difference between each pair.

5. Method (200) according to one of claims 2 to 4, wherein the several DC voltages with different magnitudes are applied successively with increasing magnitude.

6. Method (200) according to one of the preceding claims, comprising preventing (210) the application of an alternating voltage to the charging port (150) until the functionality of the at least one mains voltage sensor (151 , 152, 153) has been determined (270).

7. Method according to one of the preceding claims, comprising preventing the application (220) of the at least one predetermined DC voltage to the DC-DC converter (120) using electrical energy from the battery (110) and / or the application (230, 250) of the at least one mains voltage sensor (151, 152, 153) of the measuring voltage, depending on an input voltage applied to the charging terminal.

8. Method according to one of the preceding claims, wherein the at least one converter-side voltage sensor (125, 135) comprises two converter-side voltage sensors (125, 135), wherein a first (125) of the two converter-side voltage sensors detects a voltage between a first pole (121) and a second pole (122) of the DC-DC converter (120) and a second (135) of the two converter-side voltage sensors (125, 135) detects a voltage between the first pole (121) and a center tap of the capacitor arrangement (132). R.409840 - 14 - 9. Computing unit configured to perform all process steps of a process (200) according to any of the preceding claims.

10. Vehicle that is at least partially electrically powered, comprising a battery (110), a charging port (150) with at least one mains voltage sensor (151, 152, 153), a bidirectional DC-DC converter (120) and a power converter (140) connected between the charging port (150) and the DC-DC converter (120), wherein an intermediate circuit (130) with a capacitor arrangement (132) and at least one converter-side voltage sensor (125, 135) is provided between the power converter (140) and the DC-DC converter (120), and a computing unit according to claim 9.

11. Computer program that causes a computing unit to perform all process steps of a method (200) according to any one of claims 1 to 8 when executed on the computing unit.

12. Machine-readable storage medium with a computer program stored thereon according to claim 11.

Images