Isolation detection circuit and vehicle-mounted charger

Abstract

The embodiment of the utility model provides an isolation detection circuit and a vehicle-mounted charger. The isolation detection circuit comprises a first voltage sampling module, a second voltage sampling module, a first isolation conversion module, a second isolation conversion module, a first signal conditioning module and a second signal conditioning module. The first sampling end of the first voltage sampling module is connected with the first end of the charging port connector, the second sampling end of the first voltage sampling module is connected with the second end of the charging port connector, and the output end of the first voltage sampling module is connected with the input end of the first isolation conversion module. The output end of the first isolation conversion module is connected with the input end of the first signal conditioning module, and the output end of the first signal conditioning module is connected with the first control module. And the voltage at the two ends of the charging port connector can be accurately and reliably detected.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electronic circuit, in particular to an isolation detection circuit and a vehicle-mounted charger. BACKGROUND

[0002] At present, new energy vehicles are generally equipped with vehicle-mounted chargers (OBC) for supplementing power to the vehicle when the vehicle is running out of power, and can also temporarily discharge externally through the OBC using the power battery of the vehicle. In order to ensure that the use environment of the OBC can allow the OBC to start the corresponding function, a relay is usually provided inside the OBC. Under normal circumstances, the relay should be in an open state. Since the charging port connector and the OBC AC input line are not electrically connected in a physical way, and the voltage on the charging port connector cannot be directly measured, it may cause a safety hazard. CONTENT OF THE UTILITY MODEL

[0003] The embodiment of the present application provides an isolation detection circuit and a vehicle-mounted charger, which can accurately and reliably detect the voltage across the charging port connector, thereby improving the safety of the relay operation.

[0004] The first aspect of the embodiment of the present application provides an isolation detection circuit, comprising a first voltage sampling module, a second voltage sampling module, a first isolation conversion module, a second isolation conversion module, a first signal conditioning module and a second signal conditioning module.

[0005] The first sampling end of the first voltage sampling module is connected to the first end of the charging port connector, the second sampling end of the first voltage sampling module is connected to the second end of the charging port connector, the output end of the first voltage sampling module is connected to the input end of the first isolation conversion module, the output end of the first isolation conversion module is connected to the input end of the first signal conditioning module, and the output end of the first signal conditioning module is connected to the first control module.

[0006] The first sampling end of the second voltage sampling module is connected to the first end of the charging port connector, and the second sampling end of the second voltage sampling module is connected to the second end of the charging port connector. The output end of the second voltage sampling module is connected to the input end of the second isolation conversion module, the output end of the second isolation conversion module is connected to the input end of the second signal conditioning module, and the output end of the second signal conditioning module is connected to the second control module.

[0007] In the embodiment of the present application, the voltage across the first end and the second end of the charging port connector is sampled by two voltage sampling modules. In the case of failure of one of the voltage sampling modules, the voltage across the two ends of the charging port connector can also be detected, so that the voltage across the two ends of the charging port connector can be accurately and reliably detected.

[0008] Optionally, the first voltage sampling module comprises N first voltage sampling units, a first sampling end of each first voltage sampling unit is connected to the first end of the charging port connector, a second sampling end of each first voltage sampling unit is connected to the second end of the charging port connector, and N is an integer greater than or equal to 1; the first isolation conversion module comprises N first isolation conversion units, the N first isolation conversion units correspond to the N first voltage sampling units one by one, and an input end of each first isolation conversion unit is connected to an output end of a corresponding first voltage sampling unit.

[0009] In the embodiment of the application, the first voltage sampling module comprises N first voltage sampling units, in the case that N is greater than or equal to 2, the voltage across the charging port connector can be detected in the case that one of the first voltage sampling units fails, so that the voltage across the charging port connector can be accurately and reliably detected.

[0010] The first isolation conversion module comprises N first isolation conversion units, in the case that N is greater than or equal to 2, the other first isolation conversion units can also work in the case that one of the first isolation conversion units fails, so that the reliability of the isolation detection circuit is improved.

[0011] Optionally, the first signal conditioning module comprises N first signal conditioning units, the N first signal conditioning units correspond to the N first isolation conversion units one by one, and an input end of each first signal conditioning unit is connected to an output end of a corresponding first isolation conversion unit.

[0012] In the embodiment of the application, the first signal conditioning module comprises N first signal conditioning units, each first signal conditioning unit can condition the signal output by the corresponding connected first isolation conversion unit, so that each first signal conditioning unit outputs a signal meeting the input requirements of the first control module.

[0013] In the case that N is greater than or equal to 2, the other first signal conditioning units can also work in the case that one of the first signal conditioning units fails, so that the reliability of the isolation detection circuit is improved.

[0014] Optionally, the first control module comprises N first input ends, the N first input ends correspond to the N first signal conditioning units one by one, and an output end of each first signal conditioning unit is connected to a corresponding first input end of the first control module.

[0015] In the embodiment of the application, the first control module comprises N first input ends, in the case that N is greater than or equal to 2, the other first input ends can also work in the case that one of the first input ends fails, so that the reliability of the isolation detection circuit is improved.

[0016] Optionally, the second voltage sampling module comprises N second voltage sampling units, a first sampling end of each second voltage sampling unit is connected to the first end of the charging port connector, a second sampling end of each second voltage sampling unit is connected to the second end of the charging port connector, and N is an integer greater than or equal to 1; the second isolation conversion module comprises N second isolation conversion units, the N second isolation conversion units correspond to the N second voltage sampling units one by one, and an input end of each second isolation conversion unit is connected to an output end of a corresponding second voltage sampling unit.

[0017] In the embodiments of the present application, the second voltage sampling module comprises N second voltage sampling units, in the case that N is greater than or equal to 2, the voltage across the charging port connector can be detected in the case that one of the second voltage sampling units fails, so that the voltage across the charging port connector can be accurately and reliably detected.

[0018] The second isolation conversion module comprises N second isolation conversion units, in the case that N is greater than or equal to 2, the other second isolation conversion units can also work in the case that one of the second isolation conversion units fails, so that the reliability of the isolation detection circuit is improved.

[0019] Optionally, the second signal conditioning module comprises N second signal conditioning units, the N second signal conditioning units correspond to the N second isolation conversion units one by one, and an input end of each second signal conditioning unit is connected to an output end of a corresponding second isolation conversion unit.

[0020] In the embodiments of the present application, the second signal conditioning module comprises N second signal conditioning units, each second signal conditioning unit can condition the signal output by the corresponding connected second isolation conversion unit, so that each second signal conditioning unit outputs a signal meeting the input requirements of the second control module.

[0021] In the case that N is greater than or equal to 2, the other second signal conditioning units can also work in the case that one of the second signal conditioning units fails, so that the reliability of the isolation detection circuit is improved.

[0022] Optionally, the second control module comprises N second input ends, the N second input ends correspond to the N second signal conditioning units one by one, and an output end of each second signal conditioning unit is connected to a corresponding second input end of the second control module.

[0023] In the embodiments of the present application, the second control module comprises N second input ends, in the case that N is greater than or equal to 2, the other second input ends can also work in the case that one of the second input ends fails, so that the reliability of the isolation detection circuit is improved.

[0024] Optionally, in the case that the signal between the first sampling end of the first voltage sampling module and the second sampling end of the first voltage sampling module is a direct current signal, the signal of the output end of the first voltage sampling module is positively correlated with the direct current signal;

[0025] In the case that the signal between the first sampling end of the first voltage sampling module and the second sampling end of the first voltage sampling module is an alternating current signal, and the alternating current signal is a positive half cycle, the signal of the output end of the first voltage sampling module is positively correlated with the alternating current signal;

[0026] In the case that the signal between the first sampling end of the first voltage sampling module and the second sampling end of the first voltage sampling module is an alternating current signal, and the alternating current signal is a negative half cycle, the signal of the output end of the first voltage sampling module is 0.

[0027] In the case that the signal between the first sampling end of the second voltage sampling module and the second sampling end of the second voltage sampling module is a direct current signal, the signal of the output end of the second voltage sampling module is positively correlated with the direct current signal;

[0028] In the case that the signal between the first sampling end of the second voltage sampling module and the second sampling end of the second voltage sampling module is an alternating current signal, and the alternating current signal is a positive half cycle, the signal of the output end of the second voltage sampling module is positively correlated with the alternating current signal;

[0029] In the case that the signal between the first sampling end of the second voltage sampling module and the second sampling end of the second voltage sampling module is an alternating current signal, and the alternating current signal is a negative half cycle, the signal of the output end of the second voltage sampling module is 0.

[0030] In the embodiment of the present application, the signal of the output end of the first voltage sampling module is correlated with the signal between the second sampling end of the first voltage sampling module, and the signal of the output end of the first voltage sampling module can be used to accurately determine whether the signal between the second sampling end of the first voltage sampling module is a direct current signal or an alternating current signal. The signal of the output end of the second voltage sampling module is correlated with the signal between the second sampling end of the second voltage sampling module, and the signal of the output end of the second voltage sampling module can be used to accurately determine whether the signal between the second sampling end of the second voltage sampling module is a direct current signal or an alternating current signal.

[0031] Optionally, the first voltage sampling unit comprises a first rectifier and a first isolated signal generator, and the first rectifier and the first isolated signal generator are connected in series between the first end of the charging port connector and the second end of the charging port connector.

[0032] In the embodiment of the application, the first voltage sampling unit comprises a first rectifier and a first isolation signal generator, the first rectifier having a rectifying function and a current limiting function. The first isolation signal generator can play an isolation role and can isolate the first rectifier from the first isolation conversion unit. The first isolation conversion unit comprises a first isolation signal receiver, and the first isolation signal generator and the first isolation signal receiver can constitute an optocoupler and can play a signal isolation role.

[0033] Optionally, the second voltage sampling unit comprises a second rectifier and a second isolation signal generator, the second rectifier and the second isolation signal generator being connected in series between the second end of the charging port connector and the second end of the charging port connector.

[0034] In the embodiment of the application, the second voltage sampling unit comprises a second rectifier and a second isolation signal generator, the second rectifier having a rectifying function and a current limiting function. The second signal isolation generator can play an isolation role and can isolate the second rectifier from the second isolation conversion unit. The second isolation conversion unit comprises a second isolation signal receiver, and the second signal isolation generator and the second isolation signal receiver can constitute an optocoupler and can play a signal isolation role.

[0035] The second aspect of the embodiment of the application provides a vehicle-mounted charger comprising the isolation detection circuit of the first aspect of the embodiment of the application.

[0036] Optionally, the vehicle-mounted charger further comprises a first control module, a second control module, a first AND gate circuit, a second AND gate circuit, a first driving module, a second driving module, a first relay, and a second relay.

[0037] The output end of the first control module is connected to the first input end of the first AND gate circuit and the first input end of the second AND gate circuit, the output end of the second control module is connected to the second input end of the first AND gate circuit and the second input end of the second AND gate circuit, the output end of the first AND gate circuit is connected to the input end of the first driving module, the output end of the first driving module is connected to the control end of the first relay, the output end of the second AND gate circuit is connected to the input end of the second driving module, the output end of the second driving module is connected to the control end of the second relay, the first end of the first relay is connected to the first end of the charging port connector, the second end of the first relay is connected to the first alternating current input end of the vehicle-mounted charger, the first end of the second relay is connected to the second end of the charging port connector, and the second end of the second relay is connected to the second alternating current input end of the vehicle-mounted charger.

[0038] In the embodiment of the present application, two control modules are designed, only one control module is needed to judge that the sampled signal exceeds the range, and a low level signal can be output to control the relay to be turned off, thereby improving the safety of the relay control. When the signals output by the two control modules are different, the relay can also be controlled to be turned off, thereby improving the safety of the relay control.

[0039] In the embodiment of the present application, the voltages at the first end and the second end of the charging port connector are sampled by two voltage sampling modules, in the case that one of the voltage sampling modules fails, the voltages at the two ends of the charging port connector can also be detected, thereby the voltages at the two ends of the charging port connector can be accurately and reliably detected. BRIEF DESCRIPTION OF DRAWINGS

[0040] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0041] Figure 1 is a structural schematic diagram of an isolation detection circuit provided by the embodiment of the present application;

[0042] Figure 2 is a structural schematic diagram of another isolation detection circuit provided by the embodiment of the present application;

[0043] Figure 3 is a structural schematic diagram of another isolation detection circuit provided by the embodiment of the present application;

[0044] Figure 4 is a schematic diagram of the voltage between the signal at the output end of a first voltage sampling module and the first end of the charging port connector and the second end of the charging port connector provided by the embodiment of the present application;

[0045] Figure 5 is a schematic diagram of the voltage between the signal at the output end of another first voltage sampling module and the first end of the charging port connector and the second end of the charging port connector provided by the embodiment of the present application;

[0046] Figure 6 is a structural schematic diagram of a vehicle-mounted charger provided by the embodiment of the present application. DETAILED DESCRIPTION

[0047] With reference to the drawings, the technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0048] The terms "first", "second", and the like in the specification and claims of the present application and the above drawings are used to distinguish different objects, rather than to describe a particular order. In addition, the terms "comprise" and "have" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, system, product or device including a series of steps or units is not limited to the listed steps or units, but can optionally include steps or units not listed, or can optionally include other steps or units inherent to the process, product or device.

[0049] In the present application, "embodiment" means that the specific features, structures or characteristics described in combination with the embodiment can be included in at least one embodiment of the present application. The phrase appears at various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment to other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described in the present application can be combined with other embodiments.

[0050] Please refer to Figure 1 , Figure 1 is a structural schematic diagram of an isolation detection circuit provided by an embodiment of the present application. As Figure 1 shown, the isolation detection circuit 100 includes a first voltage sampling module 11, a second voltage sampling module 12, a first isolation conversion module 21, a second isolation conversion module 22, a first signal conditioning module 31 and a second signal conditioning module 32.

[0051] The first sampling end of the first voltage sampling module 11 is connected to the first end of the charging port connector, the second sampling end of the first voltage sampling module 11 is connected to the second end of the charging port connector, the output end of the first voltage sampling module 11 is connected to the input end of the first isolation conversion module 21, the output end of the first isolation conversion module 21 is connected to the input end of the first signal conditioning module 31, and the output end of the first signal conditioning module 31 is connected to the first control module 41.

[0052] The first sampling end of the second voltage sampling module 12 is connected with the first end of the charging port connector, and the second sampling end of the second voltage sampling module 12 is connected with the second end of the charging port connector; the output end of the second voltage sampling module 12 is connected with the input end of the second isolation conversion module 22, the output end of the second isolation conversion module 22 is connected with the input end of the second signal conditioning module 32, and the output end of the second signal conditioning module 32 is connected with the second control module 42.

[0053] In the embodiment of the application, the first voltage sampling module 11 and the second voltage sampling module 12 can sample the voltage between the first end of the charging port connector and the second end of the charging port connector. In the case that one of the voltage sampling modules fails, the voltage between the two ends of the charging port connector can also be detected, so that the voltage between the two ends of the charging port connector can be accurately and reliably detected.

[0054] The charging port connector can be connected with a charging gun and a vehicle-mounted charging machine. For example, the charging gun can be connected with the vehicle-mounted charging machine through the charging port connector. The charging port connector can be a vehicle charging socket.

[0055] The first end of the charging port connector can be connected with a direct current positive pole or a fire wire (DC+ / L) of the charging gun, and the second end of the charging port connector can be connected with a direct current negative pole or a zero wire (DC- / N) of the charger. The charging port connector can support alternating current charging and direct current charging. The charging port connector can support at least one of direct current charging and alternating current charging.

[0056] The connection between the vehicle-mounted charging machine and the charging port connector supports alternating current charging and direct current charging at the same time. The connection between the vehicle-mounted charging machine and the charging port connector supports two different charging modes of direct current charging and alternating current charging, and the vehicle-mounted charging machine supports the connection of two charging port connectors. Or it supports the charging port connector compatible with direct current charging and alternating current charging.

[0057] The first isolation conversion module 21 and the second isolation conversion module 22 can play an isolation role, avoiding the interference of the high-voltage signal of the first end of the charging port connector or the second end of the charging port connector on the first signal conditioning module 31 or the second signal conditioning module 32, and can meet the safety requirements of the vehicle-mounted charging machine.

[0058] The first signal conditioning module 31 and the second signal conditioning module 32 are signal conditioning circuits for amplifying, reducing and processing signals. The first signal conditioning module 31 can convert the input signal into a signal that can be recognized by the first control module 41, and the second signal conditioning module 32 can convert the input signal into a signal that can be recognized by the second control module 42.

[0059] Two signal conditioning modules are adopted, in the case of failure of one of the signal conditioning modules, the other signal conditioning module can also work normally, and the functional safety requirement is met.

[0060] The first control module 41 and the second control module 42 can process the input signals to determine whether the voltage between the first end of the charging port connector or the second end of the charging port connector meets the condition of opening the relay in the on-board charger.

[0061] The first control module 41 and the second control module 42 can be microcontroller units (MCU).

[0062] In the embodiments of the present application, the voltages at the first end and the second end of the charging port connector are sampled by two voltage sampling modules. In the case of failure of one of the voltage sampling modules, the voltage at the two ends of the charging port connector can also be detected, so that the voltage at the two ends of the charging port connector can be accurately and reliably detected.

[0063] Optionally, the first voltage sampling module 11 includes N first voltage sampling units, the first sampling end of each first voltage sampling unit is connected to the first end of the charging port connector, the second sampling end of each first voltage sampling unit is connected to the second end of the charging port connector, and N is an integer greater than or equal to 1; the first isolation conversion module 21 includes N first isolation conversion units, the N first isolation conversion units correspond to the N first voltage sampling units one by one, and the input end of each first isolation conversion unit is connected to the output end of the corresponding first voltage sampling unit.

[0064] In the embodiments of the present application, the first voltage sampling module 11 includes N first voltage sampling units. In the case of N greater than or equal to 2, in the case of failure of one of the first voltage sampling units, the voltage at the two ends of the charging port connector can also be detected, so that the voltage at the two ends of the charging port connector can be accurately and reliably detected.

[0065] The first isolation conversion module 21 includes N first isolation conversion units. In the case of N greater than or equal to 2, in the case of failure of one of the first isolation conversion units, the other first isolation conversion units can also work, thereby improving the reliability of the isolation detection circuit.

[0066] Optionally, the first signal conditioning module 31 includes N first signal conditioning units, the N first signal conditioning units correspond to the N first isolation conversion units one by one, and the input end of each first signal conditioning unit is connected to the output end of the corresponding first isolation conversion unit.

[0067] In the embodiment of the present application, the first signal conditioning module 31 comprises N first signal conditioning units, each of which can condition the signal output by the corresponding first isolation conversion unit, so that each first signal conditioning unit outputs a signal meeting the input requirements of the first control module 41.

[0068] In the case where N is greater than or equal to 2, in the case where one of the first signal conditioning units fails, the other first signal conditioning units can also work, thereby improving the reliability of the isolation detection circuit.

[0069] Optionally, the first control module 41 comprises N first input terminals, each of which is connected to the output terminal of a corresponding first signal conditioning unit.

[0070] In the embodiment of the present application, the first control module 41 comprises N first input terminals, in the case where N is greater than or equal to 2, in the case where one of the first input terminals fails, the other first input terminals can also work, thereby improving the reliability of the isolation detection circuit.

[0071] Optionally, the second voltage sampling module 12 comprises N second voltage sampling units, the first sampling terminal of each of which is connected to the first terminal of the charging port connector, and the second sampling terminal of each of which is connected to the second terminal of the charging port connector, N being an integer greater than or equal to 1; the second isolation conversion module 22 comprises N second isolation conversion units, each of which is connected to the output terminal of a corresponding second voltage sampling unit.

[0072] In the embodiment of the present application, the second voltage sampling module 12 comprises N second voltage sampling units, in the case where N is greater than or equal to 2, in the case where one of the second voltage sampling units fails, the voltage across the charging port connector can still be detected, thereby accurately and reliably detecting the voltage across the charging port connector.

[0073] The second isolation conversion module 22 comprises N second isolation conversion units, in the case where N is greater than or equal to 2, in the case where one of the second isolation conversion units fails, the other second isolation conversion units can also work, thereby improving the reliability of the isolation detection circuit.

[0074] Optionally, the second signal conditioning module 32 comprises N second signal conditioning units, each of which is connected to the output terminal of a corresponding second isolation conversion unit.

[0075] In the embodiment of the present application, the second signal conditioning module 32 includes N second signal conditioning units. Each second signal conditioning unit can condition the signal output by the corresponding connected second isolation conversion unit, so that each second signal conditioning unit outputs a signal that meets the input requirements of the second control module 42.

[0076] In the case where N is greater than or equal to 2, in the case where one of the second signal conditioning units fails, the other second signal conditioning units can also work, thereby improving the reliability of the isolation detection circuit.

[0077] Optionally, the second control module 42 includes N second inputs, and the N second inputs correspond one-to-one to the N second signal conditioning units. The output end of each second signal conditioning unit is connected to the corresponding second input of the second control module 42.

[0078] In the embodiment of the present application, the second control module 42 includes N second inputs. In the case where N is greater than or equal to 2, in the case where one of the second inputs fails, the other second inputs can also work, thereby improving the reliability of the isolation detection circuit.

[0079] Please refer to Figure 2 , Figure 2 is another structure diagram of an isolation detection circuit provided by the embodiment of the present application. As shown in Figure 2 , the first voltage sampling module 11 includes a first rectifier 111 and a first isolation signal generator 112, and the first rectifier 111 and the first isolation signal generator 112 are connected in series between the first end of the charging port connector and the second end of the charging port connector. The first isolation conversion module 21 includes a first isolation signal receiver. Wherein, the first end of the first rectifier 111 is connected to the first end of the charging port connector, the second end of the first rectifier 111 is connected to the first end of the first isolation signal generator 112, the second end of the first isolation signal generator 112 is connected to the second end of the charging port connector, and the output end of the first isolation signal generator 112 is connected to the input end of the first isolation conversion module 21.

[0080] In this embodiment, the first voltage sampling module includes a first rectifier 111 and a first isolation signal generator 112. The first rectifier 111 has both rectification and current limiting functions. The first isolation signal generator 112 provides isolation, separating the first rectifier 111 from the first isolation conversion module 21. The first isolation signal generator 112 and the first isolation signal receiver can form an optocoupler for signal isolation. For example, the first isolation signal generator 112 may include a light-emitting diode (LED), and the first isolation signal receiver may include a photosensitive device (e.g., a photosensitive diode or a phototransistor). The first rectifier 111 may include a first diode and a first resistor. The first end of the first resistor is connected to the first end of the charging port connector, the second end of the first resistor is connected to the anode of the first diode, and the cathode of the first diode is connected to the first end of the first isolation signal generator 112 (the positions of the first diode and the first resistor can be interchanged).

[0081] Optional, such as Figure 2 As shown, the second voltage sampling module 12 includes a second rectifier 121 and a second isolation signal generator 122, which are connected in series between the first end and the second end of the charging port connector. The second isolation conversion module 22 includes a second isolation signal receiver. The second end of the second rectifier 121 is connected to the first end of the charging port connector, the second end of the second rectifier 121 is connected to the second end of the second isolation signal generator 122, the second end of the second isolation signal generator 122 is connected to the second end of the charging port connector, and the output end of the second isolation signal generator 122 is connected to the input end of the second isolation conversion module 22.

[0082] In this embodiment, the second voltage sampling module includes a second rectifier 121 and a second isolation signal generator 122. The second rectifier 121 has rectification and current limiting functions. The second isolation signal generator can isolate the second rectifier 121 from the second isolation conversion module 22. The second isolation signal generator 122 and the second isolation signal receiver can form an optocoupler to provide signal isolation. For example, the second isolation signal generator 122 may include a light-emitting diode, and the second isolation signal receiver may include a photosensitive device (e.g., a photosensitive diode or a phototransistor). The second rectifier 111 may include a second diode and a second resistor. The first end of the second resistor is connected to the first end of the charging port connector, the second end of the second resistor is connected to the positive terminal of the second diode, and the negative terminal of the second diode is connected to the first end of the second isolation signal generator 112 (wherein, the positions of the second diode and the second resistor can be interchanged).

[0083] The following is combined with Figure 3 The following is a detailed explanation using N=2 as an example.

[0084] Please see Figure 3 , Figure 3 This is a schematic diagram of another isolation detection circuit provided in an embodiment of this application. Figure 3 As shown, the isolation detection circuit 100 includes a first voltage sampling module 11, a second voltage sampling module 12, a first isolation conversion module 21, a second isolation conversion module 22, a first signal conditioning module 31, and a second signal conditioning module 32.

[0085] The first voltage sampling module 11 includes two first voltage sampling units (e.g., Figure 3 The voltage sampling units 1 and 2 shown are provided. The first sampling terminal of each first voltage sampling unit is connected to the first terminal of the charging port connector, and the second sampling terminal of each first voltage sampling unit is connected to the second terminal of the charging port connector. The first isolation conversion module 21 includes two first isolation conversion units (e.g., voltage sampling unit 1 and voltage sampling unit 2). Figure 3 As shown in the isolation conversion unit 1 and isolation conversion unit 2, the two first isolation conversion units correspond one-to-one with the two first voltage sampling units, and the input terminal of each first isolation conversion unit is connected to the output terminal of the corresponding first voltage sampling unit. Figure 3 As shown, the output terminal of voltage sampling unit 1 is connected to the input terminal of isolation conversion unit 1, and the output terminal of voltage sampling unit 2 is connected to the input terminal of isolation conversion unit 2.

[0086] The first signal conditioning module 31 includes two first signal conditioning units (such as...) Figure 3 The signal conditioning units 1 and 2 shown are provided. Each of the two first signal conditioning units corresponds one-to-one with the two first isolation conversion units, and the input terminal of each first signal conditioning unit is connected to the output terminal of the corresponding first isolation conversion unit. Figure 3 As shown, the output terminal of isolation conversion unit 1 is connected to the input terminal of signal conditioning unit 1, and the output terminal of isolation conversion unit 2 is connected to the input terminal of signal conditioning unit 2.

[0087] The first control module 41 includes two first input terminals (such as...) Figure 3 As shown in the diagram (input terminals 1 and 2), the two first input terminals correspond one-to-one with the two first signal conditioning units, and the output terminal of each first signal conditioning unit is connected to the first input terminal corresponding to the first control module 41. Figure 3 As shown, the output terminal of signal conditioning unit 1 is connected to the input terminal 1 of the first control module 41, and the output terminal of signal conditioning unit 2 is connected to the input terminal 2 of the first control module 41.

[0088] The second voltage sampling module 12 includes two second voltage sampling units (such as the voltage sampling unit 3 and the voltage sampling unit 4 shown in FIG. 3), a first sampling end of each second voltage sampling unit is connected to a first end of the charging port connector, and a second sampling end of each second voltage sampling unit is connected to a second end of the charging port connector. Figure 3 The second isolation conversion module 22 includes two second isolation conversion units (such as the isolation conversion unit 3 and the isolation conversion unit 4 shown in FIG. 3), and the two second isolation conversion units correspond to the two second voltage sampling units one by one, and an input end of each second isolation conversion unit is connected to an output end of a corresponding second voltage sampling unit. Figure 3 As shown in FIG. 3, the output end of the voltage sampling unit 3 is connected to the input end of the isolation conversion unit 3, and the output end of the voltage sampling unit 4 is connected to the input end of the isolation conversion unit 4. Figure 3

[0089] The second signal conditioning module 32 includes two second signal conditioning units (such as the signal conditioning unit 3 and the signal conditioning unit 4 shown in FIG. 3), and the two second signal conditioning units correspond to the two second isolation conversion units one by one, and an input end of each second signal conditioning unit is connected to an output end of a corresponding second isolation conversion unit. Figure 3 As shown in FIG. 3, the output end of the isolation conversion unit 3 is connected to the input end of the signal conditioning unit 3, and the output end of the isolation conversion unit 4 is connected to the input end of the signal conditioning unit 4. Figure 3

[0090] The second control module 42 includes two second input ends (such as the input end 3 and the input end 4 shown in FIG. 3), and the two second input ends correspond to the two second signal conditioning units one by one, and an output end of each second signal conditioning unit is connected to a corresponding second input end of the second control module 42. Figure 4 As shown in FIG. 3, the output end of the signal conditioning unit 3 is connected to the input end 3 of the first control module 41, and the output end of the signal conditioning unit 4 is connected to the input end 4 of the first control module 41. Figure 4

[0091] In the embodiment of the present application, there are four voltage sampling units, four isolation conversion units, and four signal conditioning units in the isolation detection circuit, corresponding to four groups of isolation detection units. The isolation detection circuit includes four groups of isolation detection units, and each group of isolation detection units includes one voltage sampling unit, one isolation conversion unit, and one signal conditioning unit. When one group of isolation detection units fails, the other three groups of isolation detection units can still work, which can meet the functional safety requirement.

[0092] ​​​Optionally, in the case that the signal between the first sampling end of the first voltage sampling module 11 and the second sampling end of the first voltage sampling module 11 is a direct current signal, the signal of the output end of the first voltage sampling module 11 is positively correlated with the direct current signal;

[0093] In the case that the signal between the first sampling end of the first voltage sampling module 11 and the second sampling end of the first voltage sampling module 11 is an alternating current signal, and the alternating current signal is a positive half cycle, the signal of the output end of the first voltage sampling module 11 is positively correlated with the alternating current signal;

[0094] In the case that the signal between the first sampling end of the first voltage sampling module 11 and the second sampling end of the first voltage sampling module 11 is an alternating current signal, and the alternating current signal is a negative half cycle, the signal of the output end of the first voltage sampling module 11 is 0; wherein when the alternating current signal is a negative half cycle, the rectifier in the first voltage sampling module 11 can block the alternating current signal from entering the first voltage sampling module 11.

[0095] In the case that the signal between the first sampling end of the second voltage sampling module 12 and the second sampling end of the second voltage sampling module 12 is a direct current signal, the signal of the output end of the second voltage sampling module 12 is positively correlated with the direct current signal;

[0096] In the case that the signal between the first sampling end of the second voltage sampling module 12 and the second sampling end of the second voltage sampling module 12 is an alternating current signal, and the alternating current signal is a positive half cycle, the signal of the output end of the second voltage sampling module 12 is positively correlated with the alternating current signal;

[0097] In the case that the signal between the first sampling end of the second voltage sampling module 12 and the second sampling end of the second voltage sampling module 12 is an alternating current signal, and the alternating current signal is a negative half cycle, the signal of the output end of the second voltage sampling module 12 is 0; wherein when the alternating current signal is a negative half cycle, the rectifier in the second voltage sampling module 12 can block the alternating current signal from entering the second voltage sampling module 12.

[0098] The signal of the output end of the first voltage sampling module 11 is related to the signal between the first end of the first voltage sampling module 11 and the second sampling end, and the signal between the second sampling end of the first voltage sampling module 11 can be accurately judged to be a direct current signal or an alternating current signal through the signal of the output end of the first voltage sampling module 11. The signal of the output end of the second voltage sampling module 12 is related to the signal between the second sampling end of the second voltage sampling module 12, and the signal between the second sampling end of the second voltage sampling module 12 can be accurately judged to be a direct current signal or an alternating current signal through the signal of the output end of the second voltage sampling module 12.

[0099] Please refer to Figure 4 , Figure 5 is a schematic diagram of the signal of the output end of the first voltage sampling module and the voltage between the first end of the charging port connector and the second end of the charging port connector provided by the embodiment of the present application. As shown in Figure 5 , the upper graph is the voltage change curve between the first end of the charging port connector and the second end of the charging port connector, and the lower graph is the voltage change curve of the output end of the first voltage sampling module 11. Wherein, the abscissa is time (t), and the ordinate is voltage (V). When there is a direct current voltage between the first end of the charging port connector and the second end of the charging port connector, the voltage of the output end of the first voltage sampling module 11 is positively related to the direct current voltage between the first end of the charging port connector and the second end of the charging port connector. That is, the voltage of the output end of the first voltage sampling module 11 rises with the rise of the direct current voltage between the first end of the charging port connector and the second end of the charging port connector. Wherein, the positive correlation can be proportional.

[0100] Similarly, when there is a direct current voltage between the first end of the charging port connector and the second end of the charging port connector, the voltage of the output end of the second voltage sampling module 12 is positively related to the direct current voltage between the first end of the charging port connector and the second end of the charging port connector. That is, the voltage of the output end of the second voltage sampling module 12 rises with the rise of the direct current voltage between the first end of the charging port connector and the second end of the charging port connector.

[0101] Please refer to Figure 5 , Figure 6 is another schematic diagram of the signal of the output end of the first voltage sampling module and the voltage between the first end of the charging port connector and the second end of the charging port connector provided by the embodiment of the present application. As shown in Figure 6As shown in the figure, the upper graph is a voltage variation curve between the first end of the charging port connector and the second end of the charging port connector, and the lower graph is a voltage variation curve of the output end of the first voltage sampling module 11. Wherein, the abscissa is time (t), and the ordinate is voltage (V). When there is an alternating voltage between the first end of the charging port connector and the second end of the charging port connector, and the alternating signal is a positive half cycle, the voltage of the output end of the first voltage sampling module 11 is positively correlated with the alternating voltage between the first end of the charging port connector and the second end of the charging port connector. When there is an alternating voltage between the first end of the charging port connector and the second end of the charging port connector, and the alternating signal is a negative half cycle, the voltage of the output end of the first voltage sampling module 11 is 0.

[0102] The alternating voltage between the first end of the charging port connector and the second end of the charging port connector is a positive half cycle, that is, the alternating voltage between the first end of the charging port connector and the second end of the charging port connector is a positive voltage (that is, the alternating voltage is greater than 0). The alternating voltage between the first end of the charging port connector and the second end of the charging port connector is a negative half cycle, that is, the alternating voltage between the first end of the charging port connector and the second end of the charging port connector is a negative voltage (that is, the alternating voltage is less than 0).

[0103] In the embodiment of the application, when there is an alternating voltage between the first end of the charging port connector and the second end of the charging port connector, the voltage of the output end of the first voltage sampling module 11 has the following characteristics: when the alternating voltage between the first end of the charging port connector and the second end of the charging port connector is a positive half cycle, the voltage of the output end of the first voltage sampling module 11 is positively correlated with the alternating voltage between the first end of the charging port connector and the second end of the charging port connector; when the alternating voltage between the first end of the charging port connector and the second end of the charging port connector is a negative half cycle, the voltage of the output end of the first voltage sampling module 11 is 0. Wherein, the positive correlation can be proportional.

[0104] Similarly, when the alternating voltage between the first end of the charging port connector and the second end of the charging port connector is a positive half cycle, the voltage of the output end of the second voltage sampling module 12 is positively correlated with the alternating voltage between the first end of the charging port connector and the second end of the charging port connector; when the alternating voltage between the first end of the charging port connector and the second end of the charging port connector is a negative half cycle, the voltage of the output end of the second voltage sampling module 12 is 0.

[0105] In the embodiment of the present application, the first voltage sampling module 11 has a one-way conduction characteristic. When the voltage between the first sampling end of the first voltage sampling module 11 and the second sampling end of the first voltage sampling module 11 is greater than 0, the first voltage sampling module 11 outputs a signal; when the voltage between the first sampling end of the first voltage sampling module 11 and the second sampling end of the first voltage sampling module 11 is less than or equal to 0, the first voltage sampling module 11 does not output a signal.

[0106] Please refer to Figure 6 , ​ is a structural schematic diagram of a vehicle-mounted charger provided by the embodiment of the present application. As shown in ​ , the vehicle-mounted charger 200 comprises an isolation detection circuit 100, a first control module 41, a second control module 42, a first AND gate circuit 51, a second AND gate circuit 52, a first driving module 61, a second driving module 62, a first relay S1 and a second relay S2.

[0107] The isolation detection circuit 100 comprises a first voltage sampling module 11, a second voltage sampling module 12, a first isolation conversion module 21, a second isolation conversion module 22, a first signal conditioning module 31 and a second signal conditioning module 32.

[0108] The first sampling end of the first voltage sampling module 11 is connected to the first end of the charging port connector, the second sampling end of the first voltage sampling module 11 is connected to the second end of the charging port connector, the output end of the first voltage sampling module 11 is connected to the input end of the first isolation conversion module 21, the output end of the first isolation conversion module 21 is connected to the input end of the first signal conditioning module 31, and the output end of the first signal conditioning module 31 is connected to the first control module 41.

[0109] The first sampling end of the second voltage sampling module 12 is connected to the first end of the charging port connector, the second sampling end of the second voltage sampling module 12 is connected to the second end of the charging port connector; the output end of the second voltage sampling module 12 is connected to the input end of the second isolation conversion module 22, the output end of the second isolation conversion module 22 is connected to the input end of the second signal conditioning module 32, and the output end of the second signal conditioning module 32 is connected to the second control module 42.

[0110] The output end of the first control module 41 is connected with the first input end of the first AND gate circuit 51 and the first input end of the second AND gate circuit 52, the output end of the second control module 42 is connected with the second input end of the first AND gate circuit 51 and the second input end of the second AND gate circuit 52, the output end of the first AND gate circuit 51 is connected with the input end of the first drive module 61, the output end of the first drive module 61 is connected with the control end of the first relay S1, the output end of the second AND gate circuit 52 is connected with the input end of the second drive module 62, the output end of the second drive module 62 is connected with the control end of the second relay S2; the first end of the first relay S1 is connected with the first end of the charging port connector, the second end of the first relay S1 is connected with the first AC input end of the on-board charger 200, the first end of the second relay S2 is connected with the second end of the charging port connector, and the second end of the second relay S2 is connected with the second AC input end of the on-board charger 200.

[0111] The first voltage sampling module 11 and the second voltage sampling module 12 can belong to the components of the on-board charger 200 or can not belong to the components of the on-board charger.

[0112] In the embodiment, two control modules are designed, and only one control module is needed to judge that the sampled signal exceeds the range, and a low-level signal can be output to control the relay to be turned off, thereby improving the safety of the relay control. When the signals output by the two control modules are different, the relay can also be controlled to be turned off, thereby improving the safety of the relay control.

[0113] The working principle of the on board charger (OBC) is as follows: the first voltage sampling module 11 and the second voltage sampling module 12 have a one-way conduction characteristic, when the voltage between the first sampling end of the first voltage sampling module 11 and the second sampling end of the first voltage sampling module 11 is greater than 0, the first voltage sampling module 11 will output a signal; when the voltage between the first sampling end of the first voltage sampling module 11 and the second sampling end of the first voltage sampling module 11 is less than or equal to 0, the first voltage sampling module 11 will not output a signal. When the first voltage sampling module 11 outputs a signal, the first isolation conversion module 21 converts the electrical signal flowing through the circuit into an isolated signal and outputs it to the first signal conditioning module 31, and the first signal conditioning module 31 amplifies or reduces the isolated signal and outputs it to the first control module 41. After the first control module 41 obtains the signal output by the first signal conditioning module 31, it calculates the voltage between the first end of the charging port connector and the second end of the charging port connector, and determines how to drive the first relay S1 and the second relay S2. To prevent the relay from being mistakenly driven to the closed state, the first control module 41 and the second control module 42 will output signals to the input ends of the first AND gate circuit 51 and the second AND gate circuit 52. When the first control module 41 and the second control module 42 enable the relay drive, the relay will be driven to close, thereby improving the safety of the on board charger.

[0114] Among them, the first voltage sampling module 11 and the second voltage sampling module 12 have a rectifying effect and a current limiting effect to prevent the current flowing through the isolation detection circuit from being too large when high voltage appears at the sampling end.

[0115] The first isolation conversion module 21 and the second isolation conversion module 22 can convert the voltage between the first end of the charging port connector and the second end of the charging port connector into an isolated signal and transmit it to the first signal conditioning module 31 and the second signal conditioning module 32, respectively;

[0116] The first signal conditioning module 31 and the second signal conditioning module 32 respectively receive signals from the first isolation conversion module 21 and the second isolation conversion module 22, and convert them into signals at the input ends of the first control module 41 and the second control module 42 in proportion.

[0117] The first control module 41 calculates the voltage between the first end of the charging port connector and the second end of the charging port connector through the signal output by the first signal conditioning module 31, and outputs a high level to the first input end of the first AND gate circuit 51 and the first input end of the second AND gate circuit 52 when it is detected that the voltage between the first end of the charging port connector and the second end of the charging port connector is a direct current voltage and greater than a set value (for example, the set value can be set to a direct current voltage of 60V or a direct current voltage of 30V). The second control module 42 calculates the voltage between the first end of the charging port connector and the second end of the charging port connector through the signal output by the second signal conditioning module 32, and outputs a high level to the second input end of the first AND gate circuit 51 and the second input end of the second AND gate circuit 52 when it is detected that the voltage between the first end of the charging port connector and the second end of the charging port connector is a direct current voltage and greater than a set value (for example, the set value can be set to a direct current voltage of 60V or a direct current voltage of 30V). When the first input end and the second input end of the first AND gate circuit 51 are both high, the output end of the first AND gate circuit 51 outputs a high level, enabling the first drive module 61, thereby driving the first relay S1 to be in a closed state. When the first input end and the second input end of the second AND gate circuit 52 are both high, the output end of the second AND gate circuit 52 outputs a high level, enabling the second drive module 62, thereby driving the second relay S2 to be in a closed state.

[0118] The first drive module 61 is used to drive the first relay S1, and the second drive module 62 is used to drive the second relay S2. The first relay S1 is a circuit breaker on the L line, used to cut off the connection between the internal L1 line (the L1 line can be one of the three-phase lines) of the on-board charger and the charging port connector. The second relay S2 is a circuit breaker on the N line, used to cut off the connection between the internal N1 line (the N1 line can be a zero line) of the on-board charger and the charging port connector.

[0119] In the embodiments of the present application, the first voltage sampling module 11 and the first voltage sampling module 11 do not need to be configured with a dedicated power supply, and directly use the voltage from the charging gun on the charging port connector, which is low in cost and easy to implement. The design of the first voltage sampling module 11 and the first voltage sampling module 11 makes it easy for the isolation detection circuit to identify whether the voltage on the charging port connector is direct current or alternating current. By designing two groups of detection circuits (two voltage sampling modules, two isolation conversion modules, and two signal conditioning modules) in the isolation detection circuit, automotive safety integrity level B (ASIL B) can be achieved. Each detection circuit can be designed with two isolation detection units, which can achieve automotive safety integrity level D (ASIL D) for functional safety. Each detection circuit can be designed with two isolation detection units, which can decompose the safety target of ASIL D to ASIL B(D)+ASIL B(D), and can select two ASIL B control modules for the selection of the control module, thereby achieving low cost and high reliability. It should be noted that the control module meets the requirements of ASIL B and ASIL D, and the number of input ends (for sampling) of the control module is related. If one control module is used, ASIL D needs to be met, and if two control modules are used, ASIL B needs to be met. Compared with the cost of one control module meeting ASIL D, the cost of two control modules meeting ASIL B is lower.

[0120] In the above embodiments, the description of each embodiment has its own focus, and the parts not described in detail in a certain embodiment can be referred to the related description of other embodiments.

[0121] In several embodiments provided in the present application, it should be understood that the disclosed isolation detection circuit can be implemented in other ways. For example, the above-described isolation detection circuit embodiments are only schematic, for example, the division of the units is only a logical function division, and actual implementation can have another division manner, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed.

Claims

1. An isolated detection circuit, characterized by, The first voltage sampling module, the second voltage sampling module, the first isolation conversion module, the second isolation conversion module, the first signal conditioning module and the second signal conditioning module are included. The first sampling end of the first voltage sampling module is connected with the first end of the charging port connector, the second sampling end of the first voltage sampling module is connected with the second end of the charging port connector, the output end of the first voltage sampling module is connected with the input end of the first isolation conversion module, the output end of the first isolation conversion module is connected with the input end of the first signal conditioning module, and the output end of the first signal conditioning module is connected with the first control module. The first sampling end of the second voltage sampling module is connected with the first end of the charging port connector, and the second sampling end of the second voltage sampling module is connected with the second end of the charging port connector. The output end of the second voltage sampling module is connected with the input end of the second isolation conversion module, the output end of the second isolation conversion module is connected with the input end of the second signal conditioning module, and the output end of the second signal conditioning module is connected with the second control module.

2. The isolated detection circuit of claim 1, wherein, The first voltage sampling module includes N first voltage sampling units, the first sampling end of each first voltage sampling unit is connected with the first end of the charging port connector, the second sampling end of each first voltage sampling unit is connected with the second end of the charging port connector, and N is an integer greater than or equal to 1; the first isolation conversion module includes N first isolation conversion units, the N first isolation conversion units correspond to the N first voltage sampling units one by one, and the input end of each first isolation conversion unit is connected with the output end of the corresponding first voltage sampling unit.

3. The isolation detection circuit of claim 2, wherein, The first signal conditioning module includes N first signal conditioning units, the N first signal conditioning units correspond to the N first isolation conversion units one by one, and the input end of each first signal conditioning unit is connected with the output end of the corresponding first isolation conversion unit.

4. The isolated detection circuit of claim 3, wherein, The first control module includes N first input ends, the N first input ends correspond to the N first signal conditioning units one by one, and the output end of each first signal conditioning unit is connected with the corresponding first input end of the first control module.

5. The isolated detection circuit of claim 1, wherein, The second voltage sampling module includes N second voltage sampling units, the first sampling end of each second voltage sampling unit is connected with the first end of the charging port connector, the second sampling end of each second voltage sampling unit is connected with the second end of the charging port connector, and N is an integer greater than or equal to 1; the second isolation conversion module includes N second isolation conversion units, the N second isolation conversion units correspond to the N second voltage sampling units one by one, and the input end of each second isolation conversion unit is connected with the output end of the corresponding second voltage sampling unit.

6. The isolated detection circuit of claim 5, wherein, The second signal conditioning module includes N second signal conditioning units, the N second signal conditioning units correspond to the N second isolation conversion units one by one, and the input end of each second signal conditioning unit is connected with the output end of the corresponding second isolation conversion unit.

7. The isolated detection circuit of claim 6, wherein, The second control module comprises N second inputs corresponding to the N second signal conditioning units, and the output of each second signal conditioning unit is connected to the corresponding second input of the second control module.

8. The isolated detection circuit according to any one of claims 1-7, characterized in that, in the case that the signal between the first sampling end of the first voltage sampling module and the second sampling end of the first voltage sampling module is a direct current signal, the signal at the output end of the first voltage sampling module is positively correlated with the direct current signal; in the case that the signal between the first sampling end of the first voltage sampling module and the second sampling end of the first voltage sampling module is an alternating current signal, and the alternating current signal is a positive half cycle, the signal at the output end of the first voltage sampling module is positively correlated with the alternating current signal; in the case that the signal between the first sampling end of the first voltage sampling module and the second sampling end of the first voltage sampling module is an alternating current signal, and the alternating current signal is a negative half cycle, the signal at the output end of the first voltage sampling module is 0; in the case that the signal between the first sampling end of the second voltage sampling module and the second sampling end of the second voltage sampling module is a direct current signal, the signal at the output end of the second voltage sampling module is positively correlated with the direct current signal; in the case that the signal between the first sampling end of the second voltage sampling module and the second sampling end of the second voltage sampling module is an alternating current signal, and the alternating current signal is a positive half cycle, the signal at the output end of the second voltage sampling module is positively correlated with the alternating current signal; in the case that the signal between the first sampling end of the second voltage sampling module and the second sampling end of the second voltage sampling module is an alternating current signal, and the alternating current signal is a negative half cycle, the signal at the output end of the second voltage sampling module is 0.

9. The isolated detection circuit of claim 2, wherein, The first voltage sampling unit comprises a first rectifier and a first isolated signal generator, which are connected in series between the first end of the charging port connector and the second end of the charging port connector.

10. An on-board charger, characterized in that, The isolated detection circuit, the first control module, the second control module, the first AND gate circuit, the second AND gate circuit, the first driving module, the second driving module, the first relay and the second relay as claimed in any one of claims 1-9 are included. The output end of the first control module is connected with the first input end of the first AND gate circuit and the first input end of the second AND gate circuit, the output end of the second control module is connected with the second input end of the first AND gate circuit and the second input end of the second AND gate circuit, the output end of the first AND gate circuit is connected with the input end of the first drive module, the output end of the first drive module is connected with the control end of the first relay, the output end of the second AND gate circuit is connected with the input end of the second drive module, and the output end of the second drive module is connected with the control end of the second relay. The first end of the first relay is connected with the first end of the charging port connector, the second end of the first relay is connected with the first AC input end of the on-board charger, the first end of the second relay is connected with the second end of the charging port connector, and the second end of the second relay is connected with the second AC input end of the on-board charger.

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