Short circuit detection method, detection circuit and charging equipment

Abstract

The invention relates to a short circuit detection method, a detection circuit and charging equipment. The detection circuit comprises an output module which is used for providing a bidirectional current path between a first node and a second node and providing an effective level for a signal output end when current in a first direction exists in the bidirectional current path; the first trigger module and the second trigger module are used for starting to provide a bidirectional current path between the input end and the output end in an enabled state when a zero crossing point of a voltage waveform between the input end and the output end is detected until a current value in the bidirectional current path is lower than a current threshold value; and the enabling module is used for setting the first triggering module and the second triggering module to be in an enabling state when the switching signal end provides a starting level. The method comprises the step of determining that a short circuit occurs when it is detected that a switching signal end is provided with a turn-on level and no effective level exists at a signal output end. According to the invention, zero-live wire short circuit detection can be realized by using the zero-cross detection circuit structure.

Description

Technical Field

[0001] The present application relates to the field of electronic and electrical technology, and in particular to a short circuit detection method, a detection circuit and a charging device. Background Art

[0002] With the continuous development and application of new energy vehicle related technologies, more and more electric-powered vehicles and equipment are appearing in people's daily lives, and the number of charging equipment such as charging piles and charging stations used to charge vehicles and equipment has also increased. The AC charging pile is connected to the neutral and live wires of the mains through a relay, so that when the relay contacts are closed, the charging pile can start and start charging the user's equipment.

[0003] Short circuit protection is a necessary function of AC power supply equipment. Before energy transmission, when the AC output circuit is short-circuited, the AC power supply equipment should not be able to charge. During the energy transmission stage, when the AC output circuit is short-circuited, the AC power supply equipment should stop charging. For the above-mentioned AC charging pile, in order to prevent the dangerous situation that the neutral wire and the live wire are short-circuited but the relay contacts are in a closed state and charging is still in progress, the AC charging pile needs to be equipped with a short-circuit detection circuit that can respond quickly and is safe and reliable. Summary of the invention

[0004] The present application provides a short-circuit detection method, a detection circuit and a charging device, which can realize zero-live short-circuit detection by utilizing a circuit structure for realizing zero-crossing detection.

[0005] The present application provides a short circuit detection method, which is implemented by a detection circuit, wherein the detection circuit has a switch signal terminal, a signal output terminal, a live wire connection terminal, and a neutral wire connection terminal, and includes:

[0006] an output module, the output module being connected to the signal output terminal, the first node, and the second node respectively, the output module being configured to: provide a bidirectional current path between the first node and the second node, and provide a valid level to the signal output terminal when there is a current in a first direction in the bidirectional current path; the first direction is a direction from the first node to the second node, or the first direction is a direction from the second node to the first node;

[0007] a first trigger module and a second trigger module, wherein the input end of the first trigger module is connected to the live wire connection end, the output end of the first trigger module is connected to the first node, the input end of the second trigger module is connected to the neutral wire connection end, and the output end of the second trigger module is connected to the second node, and the first trigger module and the second trigger module are both configured to: in an enabled state, when a zero crossing point of a voltage waveform between the input end and the output end is detected, start to provide a bidirectional current path between the input end and the output end until a current value in the bidirectional current path is lower than a current threshold; and,

[0008] an enabling module, the enabling module being connected to the switch signal terminal, the first trigger module and the second trigger module respectively, and the enabling module being configured to set the first trigger module and the second trigger module to the enabling state when the switch signal terminal provides an on level;

[0009] The method comprises:

[0010] When it is detected that the switch signal terminal is provided with the on level and the signal output terminal does not have the valid level, it is determined that a short circuit occurs between the live wire connection terminal and the neutral wire connection terminal.

[0011] In some possible implementations, when it is detected that the switch signal terminal is provided with the on level but the signal output terminal does not have the valid level, determining that a short circuit occurs between the live wire connection terminal and the neutral wire connection terminal includes:

[0012] Providing a switch control signal to the switch signal terminal, and detecting a voltage output by the signal output terminal;

[0013] When it is detected that the switch control signal is at the on level and there is no valid level at the signal output terminal, it is determined that a short circuit occurs between the live wire connection terminal and the neutral wire connection terminal.

[0014] The present application also provides a detection circuit, the detection circuit having a switch signal terminal, a signal output terminal, a live wire connection terminal and a neutral wire connection terminal, and the detection circuit includes:

[0015] an output module, the output module being connected to the signal output terminal, the first node, and the second node respectively, the output module being configured to: provide a bidirectional current path between the first node and the second node, and provide a valid level to the signal output terminal when there is a current in a first direction in the bidirectional current path; the first direction is a direction from the first node to the second node, or the first direction is a direction from the second node to the first node;

[0016] a first trigger module and a second trigger module, wherein the input end of the first trigger module is connected to the live wire connection end, the output end of the first trigger module is connected to the first node, the input end of the second trigger module is connected to the neutral wire connection end, and the output end of the second trigger module is connected to the second node, and the first trigger module and the second trigger module are both configured to: in an enabled state, when a zero-crossing point of a voltage waveform between the input end and the output end is detected, start to provide a bidirectional current path between the input end and the output end until a current value in the bidirectional current path is lower than a current threshold;

[0017] An enabling module, wherein the enabling module is respectively connected to the switch signal end, the first trigger module and the second trigger module, and the enabling module is configured to set the first trigger module and the second trigger module to the enabling state when the switch signal end provides an on level.

[0018] In some possible implementations, each of the first trigger module and the second trigger module includes: a light-emitting unit, a zero-crossing detection unit and a bidirectional thyristor unit; wherein the light-emitting unit is connected to the enabling module, and the light-emitting unit is configured to emit light under the drive of the enabling module; the zero-crossing detection unit is respectively connected to the input end and the output end of the first trigger module or the second trigger module, and the zero-crossing detection unit is configured to provide a trigger current to the bidirectional thyristor unit when a zero-crossing point of a voltage waveform between the input end and the output end is detected; the bidirectional thyristor unit is respectively connected to the input end and the output end of the first trigger module or the second trigger module, and the bidirectional thyristor unit is configured to: when the light-emitting unit receives the trigger current in the state of emitting light, provide a bidirectional current path between the input end and the output end until the current value in the bidirectional current path is lower than the current threshold.

[0019] In some possible implementations, the enabling module includes a switching element, the switching element, the light-emitting unit of the first trigger module, and the light-emitting unit of the second trigger module are connected in series between a DC power supply voltage line and a common end of the detection circuit, the switch control end of the switching element is connected to the switch signal end, and the switching element is configured to switch to an on state when the switch signal end provides the turn-on level.

[0020] In some possible implementations, the enabling module includes a first transistor, a first resistor, a second resistor and a third resistor; wherein, the gate of the first transistor is connected to the switch signal end through the two ends of the first resistor, the first electrode of the first transistor is connected to the common end of the detection circuit, the second electrode of the first transistor is connected to the negative end of the light-emitting unit of the second trigger module, the two ends of the second resistor are respectively connected to the gate of the first transistor and the common end, the two ends of the third resistor are respectively connected to the positive end of the light-emitting unit of the first trigger module and the DC power supply voltage line, and the negative end of the light-emitting unit of the first trigger module is connected to the positive end of the light-emitting unit of the second trigger module.

[0021] In some possible implementations, the detection circuit further includes an input switch connected between the enable module and the switch signal terminal, and the input switch is configured to provide a gate turn-on voltage signal of the first transistor to the enable module when the switch signal terminal provides the turn-on level.

[0022] In some possible implementations, the first direction is the direction from the second node to the first node, and the output module includes a first diode, a second diode and a photosensitive element; wherein the anode of the first diode is connected to the first node, and the cathode of the first diode is connected to the second node; the cathode of the second diode is connected to the first node, and the anode of the second diode is connected to the second node; the two ends of the photosensitive element are respectively connected to a DC power supply voltage line and the signal output end; the second diode is a light-emitting diode, and the photosensitive element is configured to switch to a conducting state when the second diode emits light.

[0023] The present application also provides a charging device, which includes a controller, the controller includes a processor and a memory, the memory stores at least one executable instruction, and the processor is used to implement any of the above-mentioned short-circuit detection methods when executing the executable instruction.

[0024] In some possible implementations, the charging device further includes at least one detection circuit of any one of the above, and the controller is respectively connected to a switch signal terminal and a signal output terminal of each of the detection circuits.

[0025] The detection circuit in the embodiment of the present application can present different input-output characteristics when a zero-live short circuit occurs and when a zero-live short circuit does not occur. When a zero-live short circuit occurs, no matter whether each bidirectional current path is provided, there is no current between the first node and the second node, so that no matter whether the switch signal end provides an on level, the output module cannot provide a valid level to the signal output end. When a zero-live short circuit does not occur, the signal output end remains in a state of no valid level when the on level is not provided (the first node is disconnected from the live connection end, the second node is disconnected from the zero connection end, and thus there is no current between the first node and the second node). When the on level is provided, the output module will periodically provide an effective level to the signal output terminal as the mains voltage signal between the live wire and the neutral wire fluctuates (there is a current flowing from the first node to the second node during the positive half cycle of the voltage waveform, and there is a current flowing from the second node to the first node during the negative half cycle of the voltage waveform, and the output module provides an effective level to the signal output terminal in one of these two time periods); Thus, the signal output by the signal output terminal can reflect the voltage zero crossing point and fluctuation cycle of the mains voltage signal, and the short circuit detection of the live wire can be realized by detecting whether there is an effective level at the signal output terminal when the switch signal terminal is provided with an on level. It can be seen that the circuit of the embodiment of the present application can help realize the short circuit detection of the live wire by using the circuit structure for realizing zero crossing detection, and the first and second trigger modules maintain the state of not providing a bidirectional current path between the neutral wire and the live wire before the voltage waveform is detected to cross the zero point for the first time after entering the enabled state, so that it can help protect other circuit structures at the moment when the electrical signal impact is prone to occur, such as startup, switch closure, power off and reconnection, etc., which helps to improve the safety and reliability of related products such as charging equipment.

[0026] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0028] Figure 1 is a structural block diagram of a detection circuit provided in an embodiment of the present application;

[0029] Figure 2 It is a schematic diagram of the steps of a short circuit detection method provided by an embodiment of the present application;

[0030] Figure 3 is a circuit structure diagram of a detection circuit provided in an embodiment of the present application;

[0031] Figure 4It is a structural block diagram of a charging device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0032] In order to make the objectives, technical solutions and advantages of the present disclosure more clear, the embodiments of the present disclosure will be further described in detail below with reference to the accompanying drawings.

[0033] The terms used in the embodiments of the present disclosure are only used to explain the embodiments of the present disclosure, and are not intended to limit the present disclosure. Unless otherwise defined, the technical terms or scientific terms used herein should be the common meanings understood by people with ordinary skills in the field to which the present disclosure belongs. The "first", "second", "third" and similar words used in the patent application specification and claims of the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, similar words such as "one" or "one" do not indicate a quantitative limit, but indicate that there is at least one. Similar words such as "include" or "comprise" mean that the elements or objects appearing in front of "include" or "comprise" include the elements or objects listed after "include" or "comprise" and their equivalents, and do not exclude other elements or objects. Similar words such as "connect" or "connected" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect.

[0034] Figure 1 is a structural block diagram of a detection circuit provided in an embodiment of the present application. Figure 1The detection circuit has a switch signal terminal TA, a signal output terminal TB, a live connection terminal TL and a neutral connection terminal TN, and includes an output module 11, a first trigger module 12, a second trigger module 13 and an enable module 14. The output module 11 is connected to the signal output terminal TB, the first node P1 and the second node P2 respectively, and is configured to: provide a bidirectional current path between the first node P1 and the second node P2, and provide a valid level to the signal output terminal TB when there is a current flowing from the second node P2 to the first node P1 in the bidirectional current path. The input end of the first trigger module 12 is connected to the live connection terminal TL, the output end of the first trigger module 12 is connected to the first node P1, the input end of the second trigger module 13 is connected to the neutral connection terminal TN, and the output end of the second trigger module 13 is connected to the second node P2. The first trigger module 12 and the second trigger module 13 are both configured to: in the enabled state, when the zero-crossing point of the voltage waveform between the input terminal and the output terminal is detected, start to provide a bidirectional current path between the input terminal and the output terminal until the current value in the bidirectional current path is lower than the current threshold. The enabling module 14 is respectively connected to the switch signal terminal TA, the first trigger module 12 and the second trigger module 13 , and is configured to set the first trigger module 12 and the second trigger module 13 to an enabling state when the switch signal terminal TA provides an on level.

[0035] In one example, the live wire connection terminal TL of the detection circuit is used to connect the live wire of the mains power grid (which can be, for example, any one of the three live wires in the three-phase power grid), and the live wire connection terminal TN of the detection circuit is used to connect the neutral wire of the mains power grid. The above-mentioned switch signal terminal TA can be regarded as the signal input terminal of the detection circuit, and the above-mentioned signal output terminal TB is the signal output terminal of the detection circuit. Therefore, the detection circuit can realize zero-crossing detection based on the following working principle, and can use the circuit structure that realizes zero-crossing detection to help realize zero-live short-circuit detection at the same time.

[0036] Scenario 1: When there is no short circuit between the live wire connection terminal TL and the neutral wire connection terminal TN, and the switch signal terminal TA does not provide an on-level: Since the switch signal terminal TA does not provide an on-level, the enable module 14 does not work, so that the first trigger module 12 and the second trigger module 13 are never in an enabled state, and thus the first node P1 and the live wire connection terminal TL remain disconnected (a state in which a bidirectional current path is not provided), and the second node P2 and the neutral wire connection terminal TN also remain disconnected (a state in which a bidirectional current path is not provided); thus, even if a bidirectional current path is provided between the first node P1 and the second node P2, no current flows, and the output module 11 does not provide a valid level to the signal output terminal TB, so that the detection circuit as a whole remains in a state of no output (such as a state of continuously outputting a low level or an invalid level).

[0037] Scenario 2: When there is no short circuit between the live connection terminal TL and the neutral connection terminal TN, and the switch signal terminal TA provides an on level: After the switch signal terminal TA starts to provide an on level, the enabling module 14 works normally, and sets the first trigger module 12 and the second trigger module 13 to the enabled state. At the zero point of the first voltage waveform of the mains voltage signal between the live connection terminal TL and the neutral connection terminal TN, the first trigger module 12 and the second trigger module 13 in the enabled state respectively provide a bidirectional current path between the first node P1 and the live connection terminal TL, and a bidirectional current path between the second node P2 and the neutral connection terminal TN. In addition, the output module 11 provides a bidirectional current path between the first node P1 and the second node P2, so corresponding currents will be generated in these bidirectional current paths as the voltage between the live connection terminal TL and the neutral connection terminal TN changes. Taking the zero crossing point of the first voltage waveform at the beginning of a negative half cycle of the voltage waveform as an example, the current value of the current flowing from the neutral line connection terminal TN to the live line connection terminal TL will increase with the increase of the absolute value of the negative half cycle voltage, and decrease with the decrease of the absolute value of the negative half cycle voltage, until it is reduced to below the current threshold (for example, 30mA, 40mA, 50mA, 60mA, etc.); during this period, there will be a current flowing from the second node P2 to the first node P1 in the output module 11, so the output module 11 will provide a valid level to the signal output terminal TB during this period, and stop providing a valid level to the signal output terminal TB after this period ends. In this way, as the AC voltage signal of the mains voltage signal fluctuates continuously, the signal output terminal TB will output a corresponding valid level in each negative half cycle. It should be understood that the start time of each effective level output period will correspond to a voltage zero crossing point where the voltage waveform changes from positive to negative, and the end time of each effective level output period will correspond to a voltage zero crossing point where the voltage waveform changes from negative to positive. Therefore, based on the electrical signal waveform of the signal output terminal TB, the zero-crossing detection result of the AC voltage signal between the live wire connection terminal TL and the neutral wire connection terminal TN can be obtained.

[0038] Scenario three: when a short circuit occurs between the live wire connection terminal TL and the neutral wire connection terminal TN: the voltage between the live wire connection terminal TL and the neutral wire connection terminal TN is always zero, and therefore no matter whether the above-mentioned bidirectional current paths are provided, no current will ever flow between the first node P1 and the second node P2; therefore, no matter whether the switch signal terminal TA provides an on-level or not, in this case the output module 11 will maintain a state of not providing a valid level to the signal output terminal TB, and the detection circuit as a whole will maintain a state of no output (such as continuously outputting a low level or an invalid level), and will not change with changes in the input state (i.e., the output state will not change due to the switch signal terminal TA providing an on-level).

[0039] After comparison, it can be known that the above detection circuit can present different input-output characteristics when the zero-live short circuit occurs and when the zero-live short circuit does not occur - when the zero-live short circuit occurs, no matter how the input signal of the switch signal terminal TA changes, the signal output terminal TB remains in a state without a valid level output; when the zero-live short circuit does not occur, the signal output terminal TB will periodically output a valid level during the period when the switch signal terminal TA provides the turn-on level. The signal output by the signal output terminal TB can reflect the voltage zero crossing point and fluctuation period of the mains voltage signal, thereby realizing the zero-crossing detection function. Moreover, by comparing the signal logic relationship between the switch signal terminal TA and the signal output terminal TB, it can be determined whether the zero-live short circuit occurs. In one example, by detecting whether there is a valid level at the signal output terminal TB when the switch signal terminal TA is provided with an open level, the short circuit detection of the zero-live line can be realized.

[0040] Figure 2 is a schematic diagram of the steps of a short circuit detection method provided by an embodiment of the present application. Figure 2 , the short circuit detection method utilizes Figure 1 The detection circuit shown is implemented and includes the following steps.

[0041] In step 201, a switch control signal is provided to the switch signal terminal, and a voltage outputted by the signal output terminal is detected.

[0042] In step 202, when it is detected that the switch control signal is at an on level and there is no valid level at the signal output terminal, it is determined that a short circuit occurs between the live wire connection terminal and the neutral wire connection terminal.

[0043] In one example, the short circuit detection method is performed by a controller connected to the switch signal terminal TA and the signal output terminal TB respectively: in the above step 201, the controller outputs a switch control signal switching between a high level (on level) and a low level (off level) at the input / output port connected to the switch signal terminal TA, and performs voltage sampling measurement at the input / output port connected to the signal output terminal TB to detect the voltage outputted by the signal output terminal TB, and generates a zero-crossing detection signal from the change of its voltage value (as described above, under normal working conditions, the signal is in the negative half cycle of the corresponding mains voltage signal). is a valid level in each time period and maintains an invalid level in other time periods); in the above step 202, the controller compares the above switch control signal with the zero-crossing detection signal in each detection cycle to determine whether there is a situation in the current detection cycle where the switch control signal is a high level (on level) for a sufficiently long period of time but the zero-crossing detection signal always maintains an invalid level. If so, it is determined that a short circuit occurs between the live wire connection terminal and the neutral wire connection terminal, and a corresponding short-circuit protection operation is performed (such as controlling the electronic device to disconnect from the mains power grid, disconnecting the electronic device from other equipment, etc.).

[0044] It can be seen that the circuit of the embodiment of the present application can utilize the circuit structure for realizing zero-crossing detection to help realize zero-live short-circuit detection, and the first trigger module 12 and the second trigger module 13 maintain a state of not providing a bidirectional current path between the neutral line and the live line before the first detection of the zero crossing point of the voltage waveform after entering the enabled state. This can help protect other circuit structures (prevent electrical signals on the live line or the neutral line from impacting the internal circuit structure) at moments when electrical signal shocks are prone to occur, such as startup, switch closing, power failure and reconnection, and help improve the safety and reliability of related products such as charging equipment.

[0045] It should be noted that, although the above text uses "the output module 11 provides a valid level to the signal output terminal TB when there is a current flowing from the second node P2 to the first node P1 in the bidirectional current path" as an example, in other implementations, the output module 11 can be configured to provide a valid level to the signal output terminal TB when there is a current flowing from the first node P1 to the second node P2 in the bidirectional current path, so that in each positive half cycle of the above situation two, the signal output terminal TB will output a valid level, and at this time, the starting time of each valid level output time period will correspond to a voltage zero crossing point where the voltage waveform changes from negative to positive, and the end time of each valid level output time period will correspond to a voltage zero crossing point where the voltage waveform changes from positive to negative, and the working principles of other parts of the circuit remain unchanged.

[0046] It should also be noted that the switch control signal of the switch signal terminal TA in the above text is provided by the controller (an example of the execution body of the short-circuit detection method), but it may not be limited to this in other examples; for example, the switch signal terminal TA can be individually or jointly switch-controlled by a mechanical switch and / or other control device, and the above-mentioned controller (an example of the execution body of the short-circuit detection method) can implement the above-mentioned short-circuit detection process by collecting the switch control signal of the switch signal terminal TA.

[0047] It should also be noted that in any of the above-mentioned short-circuit detection methods, "the switch signal terminal TA is provided with an on level and there is no valid level at the signal output terminal TB" may not be the only factor for the controller to determine whether a short circuit occurs. The controller can add other judgment conditions such as "the power grid plug port of the electronic device is in a plugged-in state" to the short-circuit protection trigger condition (as a prerequisite for subsequent judgments, conditions that need to be met together, or conditions that can be met alone, etc.) to achieve different forms of short-circuit protection according to actual application scenarios. The embodiments of the present application are not limited to this.

[0048] Figure 3 It is a circuit structure diagram of a detection circuit provided in an embodiment of the present application.

[0049] See also Figure 3 , Figure 3 The first trigger module 12 and the second trigger module 13 in the embodiment have the same internal circuit structure, and each includes a light emitting unit LD, a zero crossing detection unit ZC and a bidirectional thyristor unit SR. The light emitting unit LD is connected to the enabling module 14, and is configured to emit light under the drive of the enabling module 14; the zero crossing detection unit ZC is respectively connected to the input end and the output end of the first trigger module 12 or the second trigger module 13, and is configured to provide a trigger current to the bidirectional thyristor unit SR when the zero crossing point of the voltage waveform between the input end and the output end is detected; the bidirectional thyristor unit SR is respectively connected to the input end and the output end of the first trigger module 12 or the second trigger module 13, and is configured to: when receiving the trigger current in the state where the light emitting unit LD emits light, provide a bidirectional current path between the input end and the output end until the current value in the bidirectional current path is lower than the current threshold.

[0050] In some examples, the first trigger module 12 and / or the second trigger module 13 are implemented by a thyristor output optocoupler chip. In this case, the light emitting unit LD is implemented by an infrared light emitting diode, the zero crossing detection unit ZC is implemented by any circuit structure having the above zero crossing detection function, and the bidirectional thyristor unit SR is implemented by Figure 3 The thyristor output optocoupler has the characteristics of good isolation performance, small footprint and strong anti-interference ability, which helps to improve the safety and reliability of the detection circuit and related products realized thereby.

[0051] See also Figure 3 , Figure 3The enabling module 14 in the embodiment includes a first transistor Q1, a first resistor R1, a second resistor R2 and a third resistor R3. Among them, the gate of the first transistor Q1 is connected to the input switch KA (i.e., the switch signal terminal TA) through the two ends of the first resistor R1. The input switch TA can be, for example, a relay or other type of controllable switch element that is switched by the switch control signal at the switch signal terminal TA. The first electrode (taking the source electrode as an example) of the first transistor Q1 is connected to the common terminal GND of the detection circuit, the second electrode (taking the drain electrode as an example) of the first transistor Q1 is connected to the negative terminal of the light-emitting unit LD of the second trigger module 13, the two ends of the second resistor R2 are respectively connected to the gate of the first transistor Q1 and the common terminal GND, the two ends of the third resistor R3 are respectively connected to the positive terminal of the light-emitting unit LD of the first trigger module 12 and the DC power supply voltage line VC (which provides a DC voltage with a fixed voltage value, such as 15V, 12V, 10V, 5.5V, 5V, 3.3V, 3V, 1.5V, etc.), and the negative terminal of the light-emitting unit LD of the first trigger module 12 is connected to the positive terminal of the light-emitting unit LD of the second trigger module 13. In this way, the light-emitting unit LD of the first trigger module 12, the light-emitting unit LD of the second trigger module 13, and the first transistor Q1 are connected in series between the DC power supply voltage line VC and the common terminal GND, and the above circuit structure forms a switch control circuit (or a driving circuit) of the two light-emitting units LD - when the first transistor Q1 works in the cut-off region (i.e., the switch is disconnected), no current passes through the two light-emitting units LD, so that the first trigger module 12 and the second trigger module 13 are in a non-enabled state; when the first transistor Q1 works in the linear region or the saturation region (i.e., the switch is on), the current passes through the two light-emitting units LD to make them emit light, so that the first trigger module 12 and the second trigger module 13 are in an enabled state (i.e., the bidirectional thyristor unit SR is in a state where it can be irradiated by the light emitted by the light-emitting unit LD). Here, the first resistor R1 plays a role in protecting the first transistor Q1 and providing an appropriate gate bias, and the second resistor R2 plays a role in stabilizing the gate voltage of the first transistor Q1 (when the input switch KA is disconnected or the switch signal terminal TA is suspended, the second resistor R2 pulls the gate voltage of the first transistor Q1 down to zero potential). The third resistor R3 plays a role in protecting the two light emitting units LD and the first transistor Q1 from large current impact.

[0052] by Figure 3Taking the circuit structure shown as an example, in some possible implementations, the enabling module 14 includes a switch element, the switch element, the light-emitting unit LD of the first trigger module 12 and the light-emitting unit LD of the second trigger module 13 are connected in series between the DC power supply voltage line VC and the common terminal GND of the detection circuit, and the switch control terminal of the switch element is connected to the switch signal terminal TA, and is configured to switch to a conducting state when the switch signal terminal TA provides an on level. For example, a device other than a metal oxide semiconductor field effect transistor (MOSFET) can be used as the above-mentioned switch element (instead of the above-mentioned first transistor Q1), such as other types of transistors, controllable resistors, controllable diodes or any other circuit structure with an equivalent switch function. Moreover, in other examples, the positions of the switch element, the light-emitting unit LD of the first trigger module 12 and the light-emitting unit LD of the second trigger module 13 in the series path can be interchanged. In addition, in some possible implementations, the enabling module 14 can also include two switch elements to respectively control whether to provide a light-emitting current for the light-emitting unit LD of the first trigger module 12 and whether to provide a light-emitting current for the light-emitting unit LD of the second trigger module 13.

[0053] exist Figure 3 In the embodiment, the detection circuit further includes an input switch K2, which is connected between the enabling module 14 and the switch signal terminal TA, and is configured to provide the enabling module 14 with a gate turn-on voltage signal of the first transistor Q1 (i.e., a gate voltage signal that enables the first transistor Q1 to operate in a linear region or a saturation region) when the switch signal terminal TA provides a turn-on level. In this way, the input switch K2 can perform a direct current-to-direct current conversion (DC-DC conversion) between the switch signal terminal TA and the above-mentioned switch element to provide a suitable turn-on voltage value for the control end of the switch element in the enabling module 14. Of course, the input switch K2 can also be omitted, and in this case, the switch signal terminal TA is directly connected to the enabling module 14.

[0054] See also Figure 3 , Figure 3The output module 11 in the circuit includes a first diode D1, a second diode D2 and a photosensitive element Q2. The anode of the first diode D1 is connected to the first node P1, and the cathode of the first diode D1 is connected to the second node P2; the cathode of the second diode D2 is connected to the first node P1, and the anode of the second diode D2 is connected to the second node P2; the two ends of the photosensitive element Q2 are respectively connected to the DC power supply voltage line VC and the signal output terminal TB; the second diode D2 is a light-emitting diode, and the photosensitive element Q2 is configured to switch to a conducting state when the second diode D2 emits light. In addition, the detection circuit also includes a fourth resistor R4, and the two ends of the fourth resistor R4 are respectively connected to the signal output terminal TB and the common terminal GND of the detection circuit. In this way, the first diode D1 and the second diode D2 can provide a bidirectional current path between the first node P1 and the second node P2, and when there is a current flowing from the second node P2 to the first node P1 in the bidirectional current path, the second diode D2 emits light and causes the photosensitive element Q2 to switch to a conducting state at this time, so that the signal output terminal TB is provided with an effective level (high level) from the DC power supply voltage line VC. The fourth resistor R4 here can stabilize the voltage at the signal output terminal TB and protect the signal output terminal TB from current shock.

[0055] See also Figure 3 In addition to the circuit structure described above, a fifth resistor R5 is connected between the output end of the first trigger module 12 and the first node P1, and a sixth resistor R6 is connected between the output end of the second trigger module 13 and the second node P2, so as to provide a sufficiently large resistance between the live wire and the neutral wire to limit the maximum current value of each bidirectional current path and protect the devices on the current path. In an example, the resistance value of the fifth resistor R5 is twice the resistance value of the sixth resistor R6, for example, the resistance value of the fifth resistor R5 is 200k ohms and the resistance value of the sixth resistor R6 is 100k ohms, so that the live wire side has a stronger ability to resist current shock.

[0056] Figure 4 is a structural block diagram of a charging device provided in an embodiment of the present application. Figure 4 The charging device includes at least one detection circuit 100 ( Figure 4 In one example, it can be a structure of any of the above detection circuits) and a controller 200 connected to the detection circuit 100. In one example, the controller 200 is respectively connected to the switch signal end and the signal output end of the detection circuit 100, and the controller 200 can be implemented with reference to any of the above short circuit detection method examples.

[0057] It should be noted that the charging device of the embodiment of the present application may be, for example, a device including at least one of a charging pile, a charging box, a charging station, a charging system, a charging circuit component, and the like, and the embodiment of the present application does not limit this. In one example, the charging device includes a charging pile and at least one charging gun (for example, one, two, three, four, five, six or more), each charging gun is connected to the charging pile, and each charging gun is configured with one, two, three or more switching elements (for example, relays), and the control end of each switching element is directly or indirectly connected to the controller 200. In addition, the controller 200 can be arranged inside the charging pile as a component of the charging pile. In one example, the above-mentioned controller 200 may include one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), controllers, microcontrollers, microprocessors or other electronic components.

[0058] It can be seen that the detection circuit in the charging device in the embodiment of the present application can utilize the circuit structure for realizing zero-crossing detection to help realize zero-live short-circuit detection, and the first and second trigger modules maintain a state of not providing a bidirectional current path between the neutral line and the live line before the first detection of the zero crossing of the voltage waveform after entering the enabled state. This can help protect other circuit structures at moments when electrical signal shocks are prone to occur, such as startup, switch closing, power off and reconnection, and help improve the safety and reliability of related products such as charging equipment.

[0059] The above description is only an optional embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the principles of the present application shall be included in the protection scope of the present application.

Claims

1. A short circuit detection method, characterized in that: The method is implemented by using a detection circuit, the detection circuit has a switch signal terminal, a signal output terminal, a live wire connection terminal and a neutral wire connection terminal, and includes: an output module, the output module being connected to the signal output terminal, the first node, and the second node respectively, the output module being configured to: provide a bidirectional current path between the first node and the second node, and provide a valid level to the signal output terminal when there is a current in a first direction in the bidirectional current path; the first direction is a direction from the first node to the second node, or the first direction is a direction from the second node to the first node; a first trigger module and a second trigger module, wherein the input end of the first trigger module is connected to the live wire connection end, the output end of the first trigger module is connected to the first node, the input end of the second trigger module is connected to the neutral wire connection end, and the output end of the second trigger module is connected to the second node, and the first trigger module and the second trigger module are both configured to: in an enabled state, when a zero crossing point of a voltage waveform between the input end and the output end is detected, start to provide a bidirectional current path between the input end and the output end until a current value in the bidirectional current path is lower than a current threshold; and, an enabling module, the enabling module being connected to the switch signal terminal, the first trigger module and the second trigger module respectively, and the enabling module being configured to set the first trigger module and the second trigger module to the enabling state when the switch signal terminal provides an on level; The method comprises: When it is detected that the switch signal terminal is provided with the on level and the signal output terminal does not have the valid level, it is determined that a short circuit occurs between the live wire connection terminal and the neutral wire connection terminal.

2. The method according to claim 1, characterized in that The step of determining that a short circuit occurs between the live wire connection terminal and the neutral wire connection terminal when it is detected that the switch signal terminal is provided with the on level but the signal output terminal does not have the valid level comprises: Providing a switch control signal to the switch signal terminal, and detecting a voltage output by the signal output terminal; When it is detected that the switch control signal is at the on level and there is no valid level at the signal output terminal, it is determined that a short circuit occurs between the live wire connection terminal and the neutral wire connection terminal.

3. A detection circuit for short circuit detection, characterized in that: The detection circuit has a switch signal terminal, a signal output terminal, a live wire connection terminal and a neutral wire connection terminal, and includes: an output module, the output module being connected to the signal output terminal, the first node, and the second node respectively, the output module being configured to: provide a bidirectional current path between the first node and the second node, and provide a valid level to the signal output terminal when there is a current in a first direction in the bidirectional current path; the first direction is a direction from the first node to the second node, or the first direction is a direction from the second node to the first node; a first trigger module and a second trigger module, wherein the input end of the first trigger module is connected to the live wire connection end, the output end of the first trigger module is connected to the first node, the input end of the second trigger module is connected to the neutral wire connection end, and the output end of the second trigger module is connected to the second node, and the first trigger module and the second trigger module are both configured to: in an enabled state, when a zero crossing point of a voltage waveform between the input end and the output end is detected, start to provide a bidirectional current path between the input end and the output end until a current value in the bidirectional current path is lower than a current threshold; and, An enabling module, wherein the enabling module is respectively connected to the switch signal end, the first trigger module and the second trigger module, and the enabling module is configured to set the first trigger module and the second trigger module to the enabling state when the switch signal end provides an on level.

4. The detection circuit according to claim 3, characterized in that: Each of the first trigger module and the second trigger module comprises: a light-emitting unit, a zero-crossing detection unit and a bidirectional thyristor unit; wherein the light-emitting unit is connected to the enabling module, and the light-emitting unit is configured to emit light under the drive of the enabling module; the zero-crossing detection unit is respectively connected to the input end and the output end of the first trigger module or the second trigger module, and the zero-crossing detection unit is configured to provide a trigger current to the bidirectional thyristor unit when a zero-crossing point of a voltage waveform between the input end and the output end is detected; the bidirectional thyristor unit is respectively connected to the input end and the output end of the first trigger module or the second trigger module, and the bidirectional thyristor unit is configured to: when receiving the trigger current in the state where the light-emitting unit is emitting light, provide a bidirectional current path between the input end and the output end until the current value in the bidirectional current path is lower than the current threshold.

5. The detection circuit according to claim 4, characterized in that: The enabling module includes a switching element, the switching element, the light-emitting unit of the first trigger module and the light-emitting unit of the second trigger module are connected in series between a DC power supply voltage line and a common end of the detection circuit, the switch control end of the switching element is connected to the switch signal end, and the switching element is configured to switch to an on state when the switch signal end provides the turn-on level.

6. The detection circuit according to claim 4, characterized in that: The enabling module includes a first transistor, a first resistor, a second resistor and a third resistor; wherein, The gate of the first transistor is connected to the switch signal end through the two ends of the first resistor, the first electrode of the first transistor is connected to the common end of the detection circuit, the second electrode of the first transistor is connected to the negative end of the light-emitting unit of the second trigger module, the two ends of the second resistor are respectively connected to the gate of the first transistor and the common end, the two ends of the third resistor are respectively connected to the positive end of the light-emitting unit of the first trigger module and the DC power supply voltage line, and the negative end of the light-emitting unit of the first trigger module is connected to the positive end of the light-emitting unit of the second trigger module.

7. The detection circuit according to claim 6, characterized in that: The detection circuit further includes an input switch connected between the enable module and the switch signal terminal, and the input switch is configured to provide a gate turn-on voltage signal of the first transistor to the enable module when the switch signal terminal provides the turn-on level.

8. The detection circuit according to any one of claims 3 to 7, characterized in that: The first direction is the direction from the second node to the first node, and the output module includes a first diode, a second diode and a photosensitive element; wherein, The anode of the first diode is connected to the first node, and the cathode of the first diode is connected to the second node; the cathode of the second diode is connected to the first node, and the anode of the second diode is connected to the second node; the two ends of the photosensitive element are respectively connected to the DC power supply voltage line and the signal output end; the second diode is a light-emitting diode, and the photosensitive element is configured to switch to a conducting state when the second diode emits light.

9. A charging device, characterized in that: The charging device includes a controller, the controller includes a processor and a memory, the memory stores at least one executable instruction, and the processor is used to implement the method according to claim 1 or 2 when executing the executable instruction.

10. The charging device according to claim 9, characterized in that: The charging device further comprises at least one detection circuit as claimed in any one of claims 3 to 8, and the controller is respectively connected to the switch signal terminal and the signal output terminal of each detection circuit.

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