Circuit arrangement for controlling a charging contactor of a charging system of an electrically operated vehicle

Abstract

The invention relates to a circuit arrangement (100) for controlling at least one charging contactor (90) of a charging system of an electrically operable vehicle, at least comprising a differential amplifier (10) with two inputs (12, 13) and one output (14), the first input (12) of which is electrically coupled to a first pole (18) of an input voltage supply of the charging system for supplying an input voltage and the second input (13) of which is electrically coupled to a second pole (19) of the input voltage supply, and a comparator (20) with two inputs (22, 23) and one output (24), the first input (22) of which is electrically coupled to the output (14) of the differential amplifier (10) and the output (24) of which is electrically coupled to a control line (83) of the at least one charging contactor (90) of the charging system.

Description

[0001] The invention relates to a circuit arrangement for controlling at least one charging contactor of a charging system of an electrically operated vehicle.

[0002] A charging connector for an electric vehicle that complies with the North American Charging Standard (NACS) allows for both direct current and alternating current charging. The unique feature of this standard is the dual use of contacts within the charging connector, depending on the voltage type. Therefore, the voltage type (DC or AC) provided by the charging station and present at the connector must be reliably detected. The NACS standard requires DC charging contactors to be closed according to the highest safety classification, ASIL D (ASIL = Automotive Safety Integrity Level according to the ISO 26262:2018 standard).

[0003] From DE 10 2022 122 383 A1, a system is known comprising a charging connector for attachment to the vehicle body of an electric or hybrid vehicle and a charging electronics unit that can be installed in the electric or hybrid vehicle for controlling the charging of a battery of the electric or hybrid vehicle, wherein the charging connector has at least one pair of direct current contacts and one pair of alternating current contacts, the charging electronics unit is provided with a direct current receiving part for connecting to the direct current contacts and an alternating current receiving part for connecting to the alternating current contacts, and the charging connector has a short-circuit device with which a respective alternating current contact can be short-circuited to a respective direct current contact in such a way that current received from the charging electronics unit via the alternating current contacts can only be received by the direct current contacts.

[0004] An object of the invention is to provide a circuit arrangement for controlling at least one charging contactor of a charging system of an electrically operated vehicle, which enables reliable detection of the voltage type.

[0005] The above-mentioned problem is solved by the features of the independent claim.

[0006] Advantageous embodiments and advantages of the invention emerge from the further claims, the description and the drawing.

[0007] According to one aspect of the invention, a circuit arrangement for controlling at least one charging contactor of a charging system of an electrically operated vehicle is proposed, comprising at least one differential amplifier with two inputs and one output. In an operating state of the circuit arrangement, the first input of the differential amplifier is electrically coupled to a first pole of an input voltage supply of the charging system for supplying an input voltage, and the second input is electrically coupled to a second pole of the input voltage supply of the charging system. The circuit arrangement further comprises a comparator with two inputs and one output, the first input of which is electrically coupled to the output of the differential amplifier and the output of which, in the operating state of the circuit arrangement, is electrically coupled to a control line of the at least one charging contactor of the charging system.

[0008] Advantageously, the proposed circuit arrangement allows for reliable detection of the voltage type (DC or AC) through the hardware design of the circuit arrangement itself. This is achieved by using a differential operational amplifier with an integrated low-pass filter and a subsequent comparator. A unique digital level is generated via the comparator stage. A level of "one" (high) at the comparator output indicates that DC voltage is above a threshold. A level of "zero" (low) indicates that the DC voltage is below the threshold or that AC voltage is present.

[0009] Based on the voltage type, it can be determined whether the charging system's at least one charging contactor can be closed. The at least one charging contactor can advantageously be controlled via the comparator's output signal.

[0010] The circuit arrangement can reliably detect the voltage type and trigger the closing of at least one charging contactor.

[0011] The voltage detection circuit itself advantageously operates entirely without software. This makes it easy to meet the stringent safety requirements of the NACS standard.

[0012] Advantageously, an existing battery management system that meets ASIL Level C does not need to be upgraded to ASIL Level D. This eliminates the need for software and hardware compared to a battery management system with ASIL Level D.

[0013] According to an advantageous embodiment of the circuit arrangement, a low-pass filter can be arranged between the output of the differential amplifier and its second input. In particular, the low-pass filter can comprise at least one capacitor and a resistor electrically connected in parallel with the capacitor. AC voltage components can be advantageously eliminated by means of the low-pass filter.

[0014] According to an advantageous embodiment of the circuit arrangement, a first voltage divider can be arranged at the two inputs of the differential amplifier to adapt the input voltage to the inputs of the differential amplifier. The voltage at the inputs of the differential amplifier can thus be advantageously limited to the required input voltage of the differential amplifier.

[0015] According to an advantageous embodiment of the circuit arrangement, a second voltage divider for defining a switching threshold of the comparator can be arranged at the second input of the comparator. This advantageously allows the switching threshold at which a DC voltage is reliably detected and a level of one is output to be determined.

[0016] According to an advantageous embodiment of the circuit arrangement, a first galvanic isolation component can be arranged at the output of the comparator, which is designed to output diagnostic information. In particular, the first galvanic isolation component can comprise an optocoupler. This allows a circuit state of the detection circuit to be output to a vehicle control unit for further processing.

[0017] According to an advantageous embodiment of the circuit arrangement, a third voltage divider can be arranged at the output of the comparator for adjusting an output signal of the comparator. This allows the voltage level of the output signal to be adjusted to an input of a subsequent optocoupler of the control stage of the at least one charging contactor.

[0018] According to an advantageous embodiment of the circuit arrangement, a second galvanic isolation component can be arranged between the output of the comparator and the driver of the at least one charging contactor. In particular, the second galvanic isolation component can follow the first galvanic isolation component. In particular, the second galvanic isolation component can comprise an optocoupler. This advantageously allows for reliable galvanic isolation due to the different electrical potentials between the high-voltage battery and the low-voltage vehicle electrical system voltage.

[0019] According to an advantageous embodiment of the circuit arrangement, a bistable circuit can be arranged at the output of the second galvanic isolation component. Such a latch circuit can prevent the voltage detection circuit from opening the at least one charging contactor.

[0020] According to an advantageous embodiment of the circuit arrangement, a logic component can be arranged between an output of the bistable component and an input of the driver of the at least one charging contactor. A first input of the logic component can be electrically coupled to the output of the bistable component, and a second input of the logic component can be electrically coupled to a control signal of a vehicle control unit. An additional input signal via the logic component provides a further enable, which must be operated by the software. This allows the opening of the at least one charging contactor to be commanded at any time.

[0021] According to an advantageous embodiment of the circuit arrangement, the logic component can be designed as an adder. Thus, a "one" state for opening the at least one charging contactor can only be output if an input from the voltage detection circuit and the additional input signal is both "one."

[0022] Further advantages will become apparent from the following description of the drawings. The drawings illustrate an exemplary embodiment of the invention. The drawings, the description, and the claims contain numerous features in combination. Those skilled in the art will also expediently consider the features individually and combine them into useful further combinations.

[0023] Showing: Fig. 1 a system overview of a circuit arrangement for controlling at least one charging contactor of a charging system of an electrically operable vehicle according to an embodiment of the invention; Fig. 2 a voltage detection circuit as part of the circuit arrangement according to Fig. 1 for detecting a voltage type of the input voltage; and Fig. 3 shows another part of the circuit arrangement according to Fig. 1 for controlling at least one charging contactor.

[0024] In the figures, identical or similar components are numbered with the same reference numerals. The figures show only examples and are not to be understood as limiting.

[0025] Fig. 1 shows a system overview of a circuit arrangement 100 for controlling at least one charging contactor 90 of a charging system of an electrically operable vehicle according to an embodiment of the invention.

[0026] The circuit arrangement 100 comprises a voltage detection circuit 110, which has at least one differential amplifier 10 and a comparator 20. The voltage detection circuit 110 is electrically coupled to a first pole 18 of an input voltage supply for supplying an input voltage and to a second pole 19 of the input voltage supply of the charging system.

[0027] The output of the voltage detection circuit 110 is electrically connected to a driver 80 of the at least one charging contactor 90 via a galvanic isolation component 50, for example, an optocoupler 51. The galvanic isolation component 50 is connected to a voltage of +5V and ground GND. The driver 80 receives an electrical supply voltage for the at least one charging contactor 90 via a line 82.

[0028] The driver 80 controls at least one charging contactor 90 via a control line 83. The charging contactor 90 is also connected to ground GND.

[0029] Fig. 2 shows the voltage detection circuit 110 as part of the circuit arrangement 100 according to Fig. 1 to detect a voltage type of the input voltage.

[0030] The voltage detection circuit 110 comprises the differential amplifier 10, which is designed as a differential operational amplifier 11 with two inputs 12, 13 and one output 14, and whose first input 12 is electrically coupled to the first pole 18 of the input voltage supply and whose second input 13 is electrically coupled to the second pole 19 of the input voltage supply of the charging system.

[0031] Furthermore, the voltage detection circuit 110 comprises the comparator 20, which is designed as a comparator module 21 with two inputs 22, 23 and one output 24, and whose first input 22 is connected to the output 14 of the differential amplifier 10 and whose output 24 is connected to the control line 83 ( Fig. 1 and Fig. 3) of at least one charging contactor 90 of the charging system is electrically coupled.

[0032] Differential amplifier 10 and comparator 20 are connected to a voltage of +5V and the ground GND.

[0033] A low-pass filter 15 is arranged between the output 14 of the differential amplifier 10 and its second input 13. The low-pass filter 15 comprises a capacitor 16 and a resistor 17 electrically connected in parallel with the capacitor 16. AC components of the input voltage can be advantageously eliminated by means of the low-pass filter 15.

[0034] A first voltage divider 40 is arranged at the two inputs 12, 13 of the differential amplifier 10 for adapting the input voltage to the inputs 12, 13 of the differential amplifier 10. The voltage divider 40 consists of two resistors connected in series between the first pole 18 and the second pole 19, respectively, and ground GND, the center taps of which are connected to the first input 12 and the second input 13, respectively. The voltage at the inputs 12, 13 of the differential amplifier 10 can thus be advantageously limited to the required input voltage of the differential amplifier 10.

[0035] A second voltage divider 25 for setting a switching threshold of the comparator 20 is arranged at the second input 23 of the comparator 20. The second voltage divider 25 consists of two resistors connected in series between the +5V voltage and ground GND, the center tap of which is connected to the second input 23 of the comparator 20. This advantageously allows the switching threshold at which a DC voltage is reliably detected and a level of one is output to be determined.

[0036] A first galvanic isolation component 30, which is designed to output diagnostic information, is arranged at output 24 of comparator 20. The first galvanic isolation component 30 can be designed, for example, as an optocoupler 31. This allows a circuit state of the detection circuit to be output to a vehicle control unit for further processing. The signal can be transmitted via an LED or a phototransistor.

[0037] The diagnosis can be performed using a control unit and / or vehicle software. This allows a diagnosis and plausibility check of the voltage detection circuit 110 to be performed, taking into account additional parameters, in particular a comparison of the charging station voltage with the battery voltage of the vehicle's high-voltage battery to be charged.

[0038] At the output 24 of the comparator 20, a third voltage divider 44 with a series-connected resistor and a resistor connected to ground GND is arranged for adjusting an output signal of the comparator 20. An output signal 45 of the voltage detection circuit 110 is present after the third voltage divider 44. This allows the voltage level of the output signal to be adjusted to an input of a subsequent optocoupler 51 of the control stage of at least one charging contactor 90.

[0039] Fig. 3 shows a further part of the circuit arrangement 100 according to Fig. 1 for controlling at least one charging contactor 90.

[0040] A second galvanic isolation component 50 is arranged between the output 24 of the comparator 20 and the driver 80 of at least one charging contactor 90. The second galvanic isolation component 50 thus follows the first galvanic isolation component 30 and can also be designed as an optocoupler 51. This advantageously allows for reliable galvanic isolation due to the different electrical potentials between the high-voltage battery and the low-voltage vehicle electrical system.

[0041] The second galvanic isolation component 50 is coupled to the output signal 45 of the voltage detection circuit 110. For electrical supply, the second galvanic isolation component 50 is connected to the +5V voltage and ground GND.

[0042] A bistable circuit 60 is arranged at the output 52 of the second galvanic isolation module 50. Such a latch circuit can prevent the voltage detection circuit 110 from opening at least one charging contactor 90 alone.

[0043] A linking component 70 is further arranged between output 61 of the bistable component 60 and an input 81 of the driver 80 of the at least one charging contactor 90.

[0044] A first input 72 of the linking component 70 is electrically coupled to the output 61 of the bistable module 60 and a second input 73 of the linking component 70 is electrically coupled to a control signal 74 of a vehicle control unit.

[0045] An additional input signal 74 via the linking component 70 provides a further enable, which must be controlled by the software. This allows the opening of at least one charging contactor 90 to be commanded at any time.

[0046] In particular, this allows the voltage level between the charging station and the vehicle's high-voltage battery to be checked. The at least one charging contactor 90 is only closed when the two voltages are equal.

[0047] The control unit has a lower functional safety than the proposed circuit arrangement 100.

[0048] The logic component 70 can be configured, for example, as an adder 71. Thus, a "one" state for opening the at least one charging contactor 90 can only be output if an input from the voltage detection circuit 110 and from the additional input signal 74 is each "one."

[0049] The output signal of the driver 80 serves as a control signal 83 for opening or closing at least one charging contactor 90 of the vehicle's charging system. List of reference symbols 10 differential amplifiers 11 differential operational amplifier 12 first entrance 13 second entrance 14 Exit 15 low-pass 16 Capacitor 17 Resistance 18 first pole 19 second pole 20 Comparator 21 Comparator module 22 first entrance 23 second entrance 24 Exit 25 second voltage divider 30 first galvanic isolation module 31 optocouplers 40 first voltage divider 44 third voltage divider 45 Output signal 50 second galvanic isolation module 51 optocouplers 52 Exit 60 bistable circuit 61 Exit 70 Linking component 71 adders 72 first entrance 73 second entrance 80 drivers 81 Input Driver 82 Power supply charging contactor 83 Control line 90 Charging contactor 100 circuit arrangement 110 Voltage detection circuit

Claims

[1] Circuit arrangement (100) for controlling at least one charging contactor (90) of a charging system of an electrically operable vehicle, at least comprising - a differential amplifier (10) with two inputs (12, 13) and one output (14), the first input (12) of which is electrically coupled to a first pole (18) of an input voltage supply of the charging system for supplying an input voltage and the second input (13) of which is electrically coupled to a second pole (19) of the input voltage supply, and - a comparator (20) with two inputs (22, 23) and one output (24), the first input (22) of which is electrically coupled to the output (14) of the differential amplifier (10) and the output (24) of which is electrically coupled to a control line (83) of the at least one charging contactor (90) of the charging system. [2] Circuit arrangement according to claim 1, wherein a low-pass filter (15) is arranged between the output (14) of the differential amplifier (10) and its second input (13), in particular wherein the low-pass filter (15) has at least one capacitor (16) and a resistor (17) electrically connected in parallel with the capacitor (16). [3] Circuit arrangement according to claim 1 or 2, wherein a first voltage divider (40) for adapting the input voltage to the inputs (12, 13) of the differential amplifier (10) is arranged at the two inputs (12, 13) of the differential amplifier (10). [4] Circuit arrangement according to one of the preceding claims, wherein a second voltage divider (25) for setting a switching threshold of the comparator (20) is arranged at the second input (23) of the comparator (20). [5] Circuit arrangement according to one of the preceding claims, wherein a first galvanic isolation component (30) is arranged at the output (24) of the comparator (20), which is designed to output diagnostic information, in particular wherein the first galvanic isolation component (30) has an optocoupler (31). [6] Circuit arrangement according to one of the preceding claims, wherein a third voltage divider (44) for adapting an output signal of the comparator (20) is arranged at the output (24) of the comparator (20). [7] Circuit arrangement according to one of the preceding claims, wherein a second galvanic isolation component (50) is arranged between the output (24) of the comparator (20) and a driver (80) of the at least one charging contactor (90), in particular wherein the second galvanic isolation module (50) follows the first galvanic isolation module (30), in particular wherein the second galvanic isolation module (50) comprises an optocoupler (51). [8] Circuit arrangement according to claim 7, wherein a bistable circuit (60) is arranged at the output (52) of the second galvanic isolation module (50). [9] Circuit arrangement according to claim 8, wherein a linking component (70) is arranged between an output (61) of the bistable component (60) and an input (81) of the driver (80) of the at least one charging contactor (90), wherein a first input (72) of the linking component (70) is electrically coupled to the output (61) of the bistable component (60) and a second input (73) of the linking component (70) is electrically coupled to a control signal (74) of a vehicle control unit. [10] Circuit arrangement according to claim 9, wherein the linking component (70) is designed as an adder (71).

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