Output short circuit detection circuit, charging short circuit detection device and charging equipment

Abstract

The utility model discloses an output short circuit detection circuit, a charging short circuit detection device and charging equipment. The output short circuit detection circuit comprises a main power circuit, a voltage division module and a sampling module, the main power circuit comprises a first switch unit, a second switch unit and a third switch unit, a first end and a second end of the first switch unit are respectively connected with a first input end and a first output end, and a first end and a second end of the second switch unit are respectively connected with a second input end and a second output end; the third switch unit is respectively connected with the first switch unit and the second switch unit in parallel; the voltage dividing module comprises a first capacitor, and the first capacitor is connected between the first output end and the second output end; the sampling module is connected between the first output end and the second output end and used for collecting the voltage of the first capacitor, and the voltage of the first capacitor is used for short circuit detection. Therefore, short-circuit detection and protection of the output end of the charging pile are realized, and the applicability of short-circuit detection is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of charging, in particular to an output short circuit detection circuit, a charging short circuit detection device and a charging device. BACKGROUND

[0002] With the popularization and promotion of new energy vehicles, the number of charging piles in the market is also increasing. Common alternating current charging piles use switching units for energy transmission. The zero and live lines of the power grid are connected to the zero and live lines of the electric vehicle charging port through two groups of switching unit contacts on the charging pile and the charging gun. When charging, the switching unit in the charging pile needs to be closed. If the output side of the charging pile is short-circuited at this time, there is a great safety hazard. Therefore, short circuit detection before charging of the charging pile output port is a prerequisite for safe charging.

[0003] At present, the short circuit detection of the output port of the charging pile is determined by the conduction state of the optocoupler, and the state of the output port is fed back to the controller. In actual use, due to the great difference in the parameters of the vehicle end load capacitance and resistance of different vehicle models on the market, the optocoupler may be misdirected, which brings inconvenience to the charging operation. CONTENT OF THE INVENTION

[0004] The main purpose of the present application is to provide an output short circuit detection circuit, a charging short circuit detection device and a charging device to realize short circuit detection and protection of the output port of the charging pile and improve the applicability of short circuit detection.

[0005] To achieve the above purpose, the present application provides an output short circuit detection circuit, which comprises a main power circuit, a voltage division module and a sampling module.

[0006] The main power circuit comprises a first switching unit, a second switching unit and a third switching unit. The first end and the second end of the first switching unit are connected with the first input end and the first output end respectively. The first end and the second end of the second switching unit are connected with the second input end and the second output end respectively. The third switching unit is connected in parallel with the first switching unit and the second switching unit respectively.

[0007] The voltage division module comprises a first capacitor, which is connected between the first output end and the second output end.

[0008] The sampling module is connected between the first output end and the second output end, and is used for collecting the voltage of the first capacitor. The voltage of the first capacitor is used for short circuit detection.

[0009] Optionally, the main power circuit further comprises a first current limiting unit and a second current limiting unit, and the third switch unit comprises a first contact and a second contact; two ends of the first contact are connected with the first input end and the first current limiting unit respectively, and two ends of the first current limiting unit are connected with the first contact and the first output end respectively; two ends of the second contact are connected with the second input end and the second current limiting unit respectively, and two ends of the second current limiting unit are connected with the second contact and the second output end respectively.

[0010] Optionally, the voltage dividing module further comprises a second capacitor and a third capacitor; the second capacitor is connected in series between the first current limiting unit and the first output end; and the third capacitor is connected in series between the second current limiting unit and the second output end.

[0011] Optionally, the main power circuit further comprises a first control unit and a second control unit; the first control unit comprises a second resistor, a first triode and a first diode; one end of the second resistor is connected with a controller, the other end of the second resistor is connected with a first pole of the first triode, a second pole of the first triode is grounded, a third pole of the first triode is connected with one end of a coil corresponding to the first contact, the other end of the coil corresponding to the first contact is connected with an external power supply, and the first diode is connected in parallel with the coil corresponding to the first contact; the second control unit comprises a third resistor, a second triode and a second diode; one end of the third resistor is connected with the controller, the other end of the third resistor is connected with a first pole of the second triode, a second pole of the second triode is grounded, a third pole of the second triode is connected with one end of a coil corresponding to the second contact, the other end of the coil corresponding to the second contact is connected with an external power supply, and the second diode is connected in parallel with the coil corresponding to the second contact.

[0012] Optionally, the third switch unit is a double-contact switch unit or is composed of two single-contact switch units.

[0013] Optionally, the sampling module comprises a plurality of fourth resistors and an operational amplifier; a part of the fourth resistors are connected in series between the first output end and a negative input end of the operational amplifier, and another part of the fourth resistors are connected in series between the second output end and a positive input end of the operational amplifier; and an output end of the operational amplifier is connected with a controller.

[0014] Optionally, the sampling module further comprises a fifth resistor, a sixth resistor and a third diode; one end of the fifth resistor is connected with the negative input end of the operational amplifier, and the other end of the fifth resistor is connected with the output end of the operational amplifier; one end of the sixth resistor is connected with the positive input end of the operational amplifier, and the other end of the sixth resistor receives a reference voltage; the third diode is connected between the positive input end and the negative input end of the operational amplifier.

[0015] Optionally, the number of fourth resistors between the first output end and the negative input end of the operational amplifier is the same as the number of fourth resistors between the second output end and the positive input end of the operational amplifier.

[0016] Optionally, the sampling module comprises a fourth resistor, a fifth resistor, a sixth resistor and a transformer; one end of the fourth resistor is connected with the first output end, and the other end of the fourth resistor is connected with one end of the primary coil of the transformer; one end of the fifth resistor is connected with the second output end, and the other end of the fifth resistor is connected with the other end of the primary coil of the transformer; the sixth resistor is connected across the secondary coil of the transformer, and one end of the secondary coil of the transformer is grounded.

[0017] In addition, to achieve the above object, the application further provides a charging short circuit detection device, comprising the output short circuit detection circuit and the controller as described above, the output short circuit detection circuit is connected with the controller, and the controller is used for detecting the voltage of the first capacitor in the output short circuit detection circuit, and the voltage of the first capacitor is used for short circuit detection.

[0018] The application further provides a charging device comprising at least one charging short circuit detection device as described above.

[0019] The output short circuit detection circuit of the application charges the first capacitor of the voltage division module for voltage division by closing the third switch unit, and the first capacitor is arranged between the first output end and the second output end, so that the voltage division of the first capacitor is the voltage division of the vehicle load capacitor or resistor; the sampling module collects the voltage of the first capacitor, and the voltage of the collected first capacitor is analyzed, so that it can be known whether the output end of the charging pile is short-circuited, the short circuit detection is realized by detecting and analyzing the voltage of the first capacitor, which can be applied to different vehicle models, and at the same time, the fault false alarm in the charging process is avoided, and the safety of charging is ensured. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is one of the circuit diagrams of the output short circuit detection circuit of the embodiment of the application;

[0021] Figure 2 is the second of the circuit diagrams of the output short circuit detection circuit of the embodiment of the application;

[0022] Figure 3 Figure 1 is a schematic diagram of a circuit structure of a first control unit according to an embodiment of the present application;

[0023] Figure 4 Figure 3 is a circuit diagram of an output short circuit detection circuit according to an embodiment of the present application;

[0024] Figure 5 Figure 5 is a schematic diagram of a sampling module according to an embodiment of the present application;

[0025] Figure 6 Figure 6 is a schematic diagram of a sampling module according to another embodiment of the present application.

[0026] The implementation, functional features and advantages of the present application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solutions and advantages of the present application more clear, the technical solutions of the present application will be described clearly and completely below with reference to the drawings in the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0028] With the increasing emphasis on environmental protection and sustainable development worldwide, the promotion and popularization of new energy vehicles are accelerating. As an important infrastructure for new energy vehicles, the market demand for charging piles has also surged. Among them, alternating current charging piles have an important position in public and private charging facilities due to their low cost, convenient installation and other advantages. However, the safety problem of alternating current charging piles, especially the short circuit risk that may occur at the output port before charging, has become one of the key factors restricting its widespread application.

[0029] Traditional alternating current charging piles usually use a switching unit to control energy transmission. By closing the switching unit contacts inside the charging pile, the zero and live lines of the power grid side are connected to the zero and live lines of the electric vehicle charging interface to charge. However, if the output port is not effectively detected for short circuit before charging begins, it may cause serious safety hazards. Therefore, ensuring that the alternating current charging pile can accurately identify the state (open circuit or short circuit) of the output port before charging becomes the key to improving charging safety.

[0030] At present, the short circuit detection methods of the output port of an alternating current charging pile include: a detection circuit with a diode and an optical coupler is used to realize short circuit detection, and specifically, the open circuit or short circuit state of the alternating current charging pile is determined by judging the output state of the optical coupler. However, when the detection circuit works, the mains is directly connected to the output side of the charging pile, and if the output is short-circuited or the resistance of the detection unit or the optical coupler fails, the mains is introduced to the isolation part of the product, which may cause the loss of part or all functions of the product, and may also cause greater risks. Secondly, in the actual use process, due to the great difference in the parameters of the load capacitance and resistance of the vehicle end of different vehicle models on the market, if the state of the output is determined based on the conduction state of the optical coupler, the optical coupler may be misdirected, thereby causing a short circuit fault misjudgment, reducing the convenience of charging operation, and further causing a safety hazard.

[0031] Based on this, the embodiment of the present application provides an output short circuit detection circuit, a charging short circuit detection device and a charging equipment. Before charging, the first switch unit and the second switch unit are opened, and the third switch unit is closed. Then, the voltage of the first capacitor is detected to determine the short circuit condition of the output port of the charging pile. If there is a short circuit condition, charging is not allowed. The short circuit protection detection before charging is realized, the applicability of the short circuit detection scheme on different vehicle models is ensured, the fault misreporting in the charging process is avoided, the convenience of charging is improved, and the safety of charging is ensured.

[0032] Figure 1 is one of the circuit diagrams of the output short circuit detection circuit of the embodiment of the present application. As shown in Figure 1 , the output short circuit detection circuit can include a main power circuit 100, a voltage division module 200 and a sampling module 300.

[0033] The main power circuit 100 includes a first switch unit K1, a second switch unit K2 and a third switch unit K3. The first end and the second end of the first switch unit K1 are connected with a first input end L_IN and a first output end L_OUT respectively. The first end and the second end of the second switch unit K2 are connected with a second input end N_IN and a second output end N_OUT respectively. The third switch unit K3 is connected in parallel with the first switch unit K1 and the second switch unit K2. The voltage division module 200 includes a first capacitor C1, which is connected between the first output end L_OUT and the second output end N_OUT. The sampling module 300 is connected between the first output end L_OUT and the second output end N_OUT, and is used to collect the voltage of the first capacitor C1. The voltage of the first capacitor C1 is used for short circuit detection.

[0034] It should be noted that the output short circuit detection circuit of the embodiments of the present application can be applied in the application scenario of detecting the short circuit of the output port of the alternating current charging pile. The first switch unit K1 and the second switch unit K2 are arranged in the charging pile. The power grid and the electric vehicle charging interface can be connected through the first switch unit K1 and the second switch unit K2, and the charging process of the charging pile can be controlled by controlling the opening and closing of the first switch unit K1 and the second switch unit K2.

[0035] In the embodiment, the first switch unit K1, the second switch unit K2 and the third switch unit K3 can all be a power relay. The current carrying capacity of the power relay is higher than that of the ordinary relay, so the power relay is more suitable for controlling high-power circuits, and is also more suitable for controlling the charging circuit of the embodiments of the present application.

[0036] Specifically, the first end of the first switch unit K1 is connected with the first input end L_IN, and the second end of the first switch unit K1 is connected with the first output end L_OUT; the first end of the second switch unit K2 is connected with the second input end N_IN, and the second end of the second switch unit K2 is connected with the second output end N_OUT. The first input end L_IN is the live line end of the power grid side, the second input end N_IN is the zero line end of the power grid side, the first output end L_OUT is the live line end of the electric vehicle charging port, and the second output end N_OUT is the zero line end of the electric vehicle charging port. The first switch unit K1 and the second switch unit K2 are connected with the controller of the charging pile. The controller can control the opening and closing of the first switch unit K1 and the second switch unit K2 by controlling whether the coils of the first switch unit K1 and the second switch unit K2 are powered, thereby controlling the energy transmission between the power grid and the electric vehicle charging port.

[0037] Further, the third switch unit K3 is used for short circuit detection. The third switch unit K3 can be connected in parallel with the first switch unit K1 and the second switch unit K2, respectively, so that the first input end L_IN and the first output end L_OUT and the second input end N_IN and the second output end N_OUT can be conducted through the third switch unit K3 for short circuit detection. In some embodiments, the third switch unit K3 is a double-contact switch unit or is composed of two single-contact switch units. Specifically, the third switch unit K3 can be a double-contact switch unit or a switch unit composed of two single-contact switch units. The two contacts of the third switch unit K3 can be connected in parallel with the first switch unit K1 and the second switch unit K2, respectively.

[0038] Continuing to refer to Figure 1In the embodiment, the voltage dividing module 200 can include a first capacitor C1 connected in series between the first output end L_OUT and the second output end N_OUT. The sampling module 300 is connected between the first output end L_OUT and the second output end N_OUT, and the input of the sampling module 300 is the voltage of the first output end L_OUT and the second output end N_OUT divided by the first capacitor C1. The sampling module 300 is mainly used to collect the voltage of the first capacitor C1 and transmit the voltage of the first capacitor C1 to the controller, so that the controller detects the voltage of the first capacitor C1.

[0039] Specifically, when the third switch unit K3 is closed and the first input end L_IN and the second input end N_IN input current, the voltage divided by the first capacitor C1 is the same as the voltage of the vehicle end load CX. Therefore, the controller can determine whether the charging pile output port is short-circuited by detecting the voltage value of the first capacitor C1. If it is detected that the voltage value of the first capacitor C1 is zero, it indicates that the charging pile output port is short-circuited, and at this time the charging pile can not be charged. If it is detected that the voltage value of the first capacitor C1 is not zero, it indicates that the charging pile output port is not short-circuited, and at this time the charging pile can be further charged.

[0040] Therefore, in the embodiment, the voltage of the first capacitor C1 is collected before charging, and whether the charging pile output port is short-circuited can be known by detecting the voltage of the first capacitor C1. The short-circuit detection scheme of the embodiment does not need to use an optical coupler and is not affected by the vehicle end load capacitor or resistor, so the short-circuit detection result is more stable and reliable, the short-circuit protection detection before charging is realized, and the applicability of the short-circuit detection scheme on different vehicle models is ensured.

[0041] In order to realize current limiting protection during the short-circuit detection process and avoid damage to components caused by overcurrent, in some embodiments, the main power circuit 100 further includes a first current limiting unit and a second current limiting unit, and the third switch unit K3 includes a first contact K3-1 and a second contact K3-2.

[0042] The two ends of the first contact K3-1 are respectively connected with the first input end L_IN and the first current limiting unit, and the two ends of the first current limiting unit are respectively connected with the first contact K3-1 and the first output end L_OUT. The two ends of the second contact K3-2 are respectively connected with the second input end N_IN and the second current limiting unit, and the two ends of the second current limiting unit are respectively connected with the second contact K3-2 and the second output end N_OUT.

[0043] In the embodiment, the first current limiting unit and the second current limiting unit can each include a first resistor R1 or at least two first resistors R1 connected in parallel.

[0044] Figure 2is a second circuit diagram of an output short circuit detection circuit of an embodiment of the present application. Referring to Figure 2 The following further introduces the output short circuit detection circuit of the embodiment, taking an example of the first current limiting unit and the second current limiting unit including a first resistor R1.

[0045] The third switch unit K3 includes two groups of power contacts (i.e., a first contact K3-1 and a second contact K3-2). One end of the first contact K3-1 of the third switch unit K3 is connected to the first input end L_IN, and the other end of the first contact K3-1 of the third switch unit K3 is connected to one end of the first resistor R1 of the first current limiting unit. The other end of the first resistor R1 of the first current limiting unit is connected to the first output end L_OUT. One end of the second contact K3-2 of the third switch unit K3 is connected to the second input end N_IN, and the other end of the second contact K3-2 of the third switch unit K3 is connected to one end of the first resistor R1 of the second current limiting unit. The other end of the first resistor R1 of the second current limiting unit is connected to the second output end N_OUT.

[0046] When the third switch unit K3 is closed and current flows through the first input end L_IN and the second input end N_IN, the first resistor R1 of the first current limiting unit and the first resistor R1 of the second current limiting unit can both play a role in current limiting, thereby avoiding the situation that components are damaged due to excessive current, and further improving the reliability and safety of the output short circuit detection circuit.

[0047] It should be noted that if the first current limiting unit and the second current limiting unit include a plurality of first resistors R1 connected in parallel, it is only necessary to replace the first resistor R1 in the above circuit structure with the first resistors R1 connected in parallel, and other connection structures are the same, which will not be described here.

[0048] In some embodiments, the main power circuit 100 further includes a first control unit and a second control unit. The first control unit and the second control unit can be used to transmit a control signal ARM_K3_CTR sent by a controller to the third switch unit K3, thereby controlling the attraction and disconnection of the third switch unit K3.

[0049] The first control unit includes a second resistor R2, a first triode Q1, and a first diode D1. One end of the second resistor R2 is connected to the controller, and the other end of the second resistor R2 is connected to the first electrode of the first triode Q1. The second electrode of the first triode Q1 is grounded, and the third electrode of the first triode Q1 is connected to one end of the first contact K3-1 corresponding coil. The other end of the first contact K3-1 corresponding coil is connected to an external power supply Vcc, and the first diode D1 is connected in parallel with the first contact K3-1 corresponding coil.

[0050] The second control unit comprises a third resistor R3, a second triode Q2 and a second diode D2; one end of the third resistor R3 is connected with the controller, the other end of the third resistor R3 is connected with the first electrode of the second triode Q2, the second electrode of the second triode Q2 is grounded, the third electrode of the second triode Q2 is connected with one end of the coil corresponding to the second contact K3-2, the other end of the coil corresponding to the second contact K3-2 is connected with the external power supply Vcc, and the second diode D2 is connected with the coil corresponding to the second contact K3-2 in parallel.

[0051] It should be noted that the third switch unit K3 comprises two groups of power contacts, and thus comprises two groups of coils, one power contact corresponding to one coil. In addition, the first electrode of the first triode can be a base, the second electrode can be an emitter, and the third electrode can be a collector; similarly, the first electrode of the second triode can be a base, the second electrode can be an emitter, and the third electrode can be a collector.

[0052] Figure 3 is a circuit structure schematic diagram of the first control unit of the embodiment of the present application. In the following, the first control unit is taken as an example to further introduce the first control unit and the second control unit. It should be noted that the circuit structure and working principle of the second control unit are the same as those of the first control unit, and thus the connection relationship and working principle of each device in the second control unit can refer to the connection relationship and working principle of each device in the first control unit.

[0053] As shown in Figure 3 , the controller outputs a control signal ARM_K3_CTR to the first control unit, and the control signal first passes through the second resistor R2, which plays a role of current limiting for the control signal. Further, the control signal is input to the first electrode of the first triode Q1, and after the first electrode of the first triode Q1 is electrified, the first triode Q1 is turned on. The coil corresponding to the first contact K3-1 of the third switch unit K3 is connected in series between the external power supply and the third electrode of the first triode Q1, and the coil has the first diode D1 connected in parallel at both ends. The second electrode of the first triode Q1 is directly connected with GND. When the first triode Q1 is turned on, there is a current flowing through the coil corresponding to the first contact K3-1, and the first contact K3-1 is attracted. The first diode D1 can be used to absorb the reverse electromotive force. Thus, whether the first contact K3-1 of the third switch unit K3 has a current flowing through the coil thereof determines whether the first contact K3-1 is attracted or disconnected.

[0054] In some embodiments, the voltage division module 200 further comprises a second capacitor C2 and a third capacitor C3; the second capacitor C2 is connected in series between the first current limiting unit and the first output end L_OUT; and the third capacitor C3 is connected in series between the second current limiting unit and the second output end N_OUT.

[0055] Figure 4is a third circuit diagram of an output short circuit detection circuit of an embodiment of the present application. Reference is made to Figure 4 The first current-limiting unit and the second current-limiting unit each include a first resistor R1. The voltage dividing module 200 is described in detail below.

[0056] Specifically, one end of the second capacitor C2 is connected to one end of the first resistor R1 in the first current-limiting unit, and the other end of the second capacitor C2 is connected to the first output terminal L_OUT. One end of the third capacitor C3 is connected to one end of the first resistor R1 in the second current-limiting unit, and the other end of the third capacitor C3 is connected to the second output terminal N_OUT. As can be seen from Figure 3 The first capacitor C1 is in parallel with the load capacitor CX of the vehicle, and is in series with the second capacitor C2 and the third capacitor C3. The first capacitor C1 divides the voltage with the second capacitor C2 and the third capacitor C3. The voltage divided by the first capacitor C1 in parallel with the load capacitor CX of the vehicle is the voltage to be collected by the sampling module 300.

[0057] The present embodiment provides two structures of the sampling module 300, which are described in detail below.

[0058] In some embodiments, the sampling module 300 includes a plurality of fourth resistors R4 and an operational amplifier U1. Some of the fourth resistors R4 are connected in series between the first output terminal L_OUT and the negative input terminal of the operational amplifier U1, and the other fourth resistors R4 are connected in series between the second output terminal N_OUT and the positive input terminal of the operational amplifier U1. The output terminal of the operational amplifier U1 is connected to the controller.

[0059] Specifically, the first sampling module 300 is a high-resistance sampling circuit. The input of the sampling module 300 is the voltage divided by the first capacitor C1, which is high-voltage alternating current. The controller ADC port cannot directly collect and detect the voltage. Therefore, the present embodiment provides a plurality of fourth resistors R4 and an operational amplifier U1. The sampling module 300 converts the high-voltage alternating current at the output side of the charging pile into a voltage range that can be processed by the controller ADC port through the operational amplifier U1.

[0060] In the present embodiment, the plurality of fourth resistors R4 can be divided into two groups, which are connected in series between the first output terminal L_OUT and the negative input terminal of the operational amplifier U1, and between the second output terminal N_OUT and the positive input terminal of the operational amplifier U1, respectively. These fourth resistors R4 can function as voltage dividing and sampling, and can also serve as a layer of reinforced insulation to isolate the high-voltage circuit from the low-voltage circuit, thereby ensuring the safety of the circuit.

[0061] In some embodiments, the number of fourth resistors R4 between the first output terminal L_OUT and the negative input terminal of the operational amplifier U1 is the same as the number of fourth resistors R4 between the second output terminal N_OUT and the positive input terminal of the operational amplifier U1. That is, each fourth resistor R4 is symmetrically connected in series between the first output terminal L_OUT, the second output terminal N_OUT, and the positive and negative input terminals of the operational amplifier U1, and the two groups of fourth resistors R4 can form two high-impedance sampling branches. It should be noted that the number of fourth resistors R4 can be an even number, and the number of fourth resistors R4 is preferably eight or more.

[0062] Figure 5 is a schematic diagram of the circuit structure of a sampling module according to an embodiment of the present application. The first sampling module 300 will be described in detail below, taking 10 fourth resistors R4 as an example.

[0063] As shown in Figure 5 , of the 10 fourth resistors R4, 5 fourth resistors R4 are connected in series between the first output terminal L_OUT and the negative input terminal of the operational amplifier U1, and the other 5 fourth resistors R4 are connected in series between the second output terminal N_OUT and the positive input terminal of the operational amplifier U1, and the output terminal of the operational amplifier U1 is connected to the controller. The controller can detect the voltage of the sampling point ARM_SHORT_FB of the output terminal of the operational amplifier U1, thereby obtaining the sampling voltage of the first capacitor C1.

[0064] In some embodiments, the first sampling module 300 can further include a fifth resistor R5, a sixth resistor R6, and a third diode VD1.

[0065] The one end of the fifth resistor R5 is connected to the negative input terminal of the operational amplifier U1, and the other end of the fifth resistor R5 is connected to the output terminal of the operational amplifier U1; the one end of the sixth resistor R6 is connected to the positive input terminal of the operational amplifier U1, and the other end of the sixth resistor R6 receives a reference voltage VREF; and the third diode VD1 is connected between the positive input terminal and the negative input terminal of the operational amplifier U1.

[0066] Continuing to refer to Figure 5 , the third diode VD1 can be a bidirectional diode, and the two ends of the third diode VD1 can be connected between the fourth resistors R4. For example, one end of the third diode VD1 can be connected to one end of the fourth fourth resistor R4 in the first high-impedance sampling branch, and the other end of the third diode VD1 can be connected to one end of the fourth fourth resistor R4 in the second high-impedance sampling branch.

[0067] The third diode VD1 can be used for clamping voltage, i.e. limiting the voltage within a certain range, so as to protect the subsequent circuit from excessive or low voltage. Specifically, when the voltage input by the first output end L_OUT and the second output end N_OUT exceeds a certain threshold, the third diode VD1 will be turned on to limit the voltage around the threshold, thereby playing a protection role.

[0068] One end of the sixth resistor R6 receives a reference voltage VREF, which is used to raise the negative half cycle of the alternating current, so as to ensure that the operational amplifier U1 can sample the output voltage into the voltage range that can be collected by the controller. It can be understood that, assuming that the original alternating current contains two half cycles of positive and negative. If there is no reference voltage VREF, the voltage of the negative half cycle will be negative, which may exceed the working range of the controller ADC. By adding a reference voltage VREF, the negative half cycle voltage can be changed to positive, thereby ensuring that the entire signal is within the input range of the controller.

[0069] Figure 6 is a circuit structure schematic diagram of a sampling module of another embodiment of the present application.

[0070] As Figure 6 shown, the second sampling module 300 can include a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, and a transformer T1; one end of the fourth resistor R4 is connected with the first output end L_OUT, and the other end of the fourth resistor R4 is connected with one end of the primary coil of the transformer T1; one end of the fifth resistor R5 is connected with the second output end N_OUT, and the other end of the fifth resistor R5 is connected with the other end of the primary coil of the transformer T1; the sixth resistor R6 is connected across the two ends of the secondary coil of the transformer T1, and one end of the secondary coil of the transformer T1 is grounded.

[0071] It should be noted that the transformer T1 can be a voltage transformer.

[0072] Specifically, the second sampling module 300 is a voltage transformer sampling circuit, and the input of the sampling module 300 is still the voltage shared by the first capacitor C1. When there is voltage between the first output end L_OUT and the second output end N_OUT, the fourth resistor R4 and the fifth resistor R5 located in the primary side of the transformer T1 can convert the voltage between the first output end L_OUT and the second output end N_OUT into current, and the fourth resistor R4 and the fifth resistor R5 simultaneously play a current limiting role. After passing through the transformer T1, the transformer T1 outputs a current signal, and the current signal is converted into a required voltage signal through the sixth resistor R6, and the sixth resistor R6 plays a sampling role.

[0073] The primary and secondary sides of the voltage transformer T1 are isolated by electromagnetism, and need to meet certain isolation voltage requirements. The above sampling method can also achieve voltage sampling of the first capacitor C1 and meet safety regulations.

[0074] Referring to the circuit structure of the output short circuit detection circuit, the process of detecting the output port short circuit of the charging pile by the output short circuit detection circuit will be described in detail.

[0075] In this embodiment, before the output port is detected for short circuit, the first switch unit K1 and the second switch unit K2 can be first detected for sticking, so as to ensure the accuracy and reliability of subsequent short circuit detection.

[0076] Specifically, the controller can first control the third switch unit K3 to be open, so as to ensure that the output short circuit detection circuit has no energy transmission before the sticking detection. Further, the controller can separately control the first switch unit K1 to be closed. At this time, the analog-to-digital converter ADC in the controller detects the voltage of the sampling point ARM_SHORT_FB, so as to obtain the voltage state of the sampling point ARM_SHORT_FB. If the controller detects that the sampling point ARM_SHORT_FB has voltage output, it indicates that the second switch unit K2 is stuck. If the controller does not detect that the sampling point ARM_SHORT_FB has voltage output, it indicates that the second switch unit K2 is not stuck.

[0077] Similarly, the controller controls the first switch unit K1 to be open, and separately controls the second switch unit K2 to be closed. At this time, the analog-to-digital converter ADC in the controller detects the voltage of the sampling point ARM_SHORT_FB, so as to obtain the voltage state of the sampling point ARM_SHORT_FB. If the controller detects that the sampling point ARM_SHORT_FB has voltage output, it indicates that the first switch unit K1 is stuck. If the controller does not detect that the sampling point ARM_SHORT_FB has voltage output, it indicates that the first switch unit K1 is not stuck.

[0078] Through the above sticking detection method, if it is detected that any switch unit is stuck, the controller reports a fault, and the charging pile does not perform short circuit detection and energy transmission. If the first switch unit K1 and the second switch unit K2 are both stuck, short circuit detection is performed.

[0079] The process of short circuit detection is as follows: the controller first controls the first switch unit K1 and the second switch unit K2 to be open, so as to ensure that there is no energy transmission in the main power circuit before short circuit detection. Further, the controller controls the third switch unit K3 to be closed. If the first output end L_OUT and the second output end N_OUT are short-circuited at this time, the first capacitor C1 is short-circuited, and the voltage across the first capacitor C1 is 0V. Therefore, the voltage input by the sampling module 300 is also 0V, and the voltage of the ADC detection sampling point ARM_SHORT_FB in the controller is also 0V. If the first output end L_OUT and the second output end N_OUT are not short-circuited, the voltage input by the power grid through the first input end L_IN and the second input end N_IN is transmitted to the first output end L_OUT and the second output end N_OUT through the two groups of contacts of the third switch unit K3. The voltage is divided by the first capacitor C1, the second capacitor C2 and the third capacitor C3, and then enters the sampling module 300. After the voltage signal is processed by the sampling module 300, it is output to the controller. The voltage of the ADC detection sampling point ARM_SHORT_FB in the controller is not 0V.

[0080] Therefore, the voltage of the ADC detection sampling point ARM_SHORT_FB in the controller can be used to determine whether the output port of the charging pile is short-circuited at this time.

[0081] On the basis of the above-mentioned embodiments, the present embodiment further provides a charging short circuit detection device. The charging short circuit detection device can include an output short circuit detection circuit and a controller as described above. The output short circuit detection circuit is connected with the controller, and the controller is configured to detect the voltage of the first capacitor in the output short circuit detection circuit, and the voltage of the first capacitor is used for short circuit detection.

[0082] The controller of the present embodiment can include an ARM (Advanced RISC Machine) core. The control signals output to the first switch unit, the second switch unit and the third switch unit can be output by the ARM core in the controller; and the voltage detection of the sampling point ARM_SHORT_FB and the short circuit judgment can also be completed by the ARM core. In addition, the short circuit detection scheme of the present embodiment can also be used in an alternating current charging pile with a power meter.

[0083] It should be noted that the details of the charging short circuit detection device not disclosed in the present embodiment are referred to the details disclosed in the embodiments of the output short circuit detection circuit in the present specification, which will not be described here.

[0084] On the basis of the above-mentioned embodiments, the present embodiment further provides a charging device, which includes at least one charging short circuit detection device as described above.

[0085] It should be noted that the details of the charging device in the embodiment not disclosed, please refer to the details disclosed in the embodiment of the output short circuit detection circuit in the description, hereinafter.

[0086] The device embodiments described above are only schematic, wherein the units described as separate components can or can not be physically separate, and the components displayed as units can or can not be physical units, i.e. can be located in one place, or can be distributed on a plurality of network units. Part or all of the modules can be selected to achieve the purpose of the embodiment scheme according to actual needs. Those skilled in the art can understand and implement without creative labor.

[0087] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. An output short detection circuit, characterized by comprising: The main power circuit comprises a first switch unit, a second switch unit and a third switch unit, the first end and the second end of the first switch unit are connected with the first input end and the first output end respectively, the first end and the second end of the second switch unit are connected with the second input end and the second output end respectively, and the third switch unit is connected with the first switch unit and the second switch unit in parallel. The voltage of the first capacitor is used for short circuit detection. The main power circuit further comprises a first current limiting unit and a second current limiting unit, and the third switch unit comprises a first contact and a second contact. The first end and the second end of the first contact are connected with the first input end and the first current limiting unit respectively, and the first end and the second end of the first current limiting unit are connected with the first contact and the first output end respectively.

2. The output short detection circuit according to claim 1, characterized by The first end and the second end of the second contact are connected with the second input end and the second current limiting unit respectively, and the first end and the second end of the second current limiting unit are connected with the second contact and the second output end respectively. The voltage of the first capacitor is used for short circuit detection. The main power circuit further comprises a first control unit and a second control unit.

3. The output short detection circuit according to claim 2, characterized by The first control unit comprises a second resistor, a first triode and a first diode, one end of the second resistor is connected with a controller, the other end of the second resistor is connected with the first pole of the first triode, the second pole of the first triode is grounded, one end of the first contact corresponding coil is connected with the third pole of the first triode, the other end of the first contact corresponding coil is connected with an external power supply, and the first diode is connected with the first contact corresponding coil in parallel. The second control unit comprises a third resistor, a second triode and a second diode, one end of the third resistor is connected with the controller, the other end of the third resistor is connected with the first pole of the second triode, the second pole of the second triode is grounded, one end of the second contact corresponding coil is connected with the third pole of the second triode, the other end of the second contact corresponding coil is connected with an external power supply, and the second diode is connected with the second contact corresponding coil in parallel. The sampling module comprises a plurality of fourth resistors and an operational amplifier.

4. The output short detection circuit according to claim 2, characterized by One part of the fourth resistors is connected in series between the first output end and the negative input end of the operational amplifier, and the other part of the fourth resistors is connected in series between the second output end and the positive input end of the operational amplifier, and the output end of the operational amplifier is connected with a controller. The sampling module further comprises a fifth resistor, a sixth resistor and a third diode. ​ 5. The output short detection circuit according to any one of claims 1 to 4, characterized by, ​ ​ 6. The output short detection circuit according to claim 5, characterized by ​ One end of the fifth resistor is connected with the negative input end of the operational amplifier, and the other end of the fifth resistor is connected with the output end of the operational amplifier; One end of the sixth resistor is connected with the positive input end of the operational amplifier, and the other end of the sixth resistor receives a reference voltage; The third diode is connected between the positive input end and the negative input end of the operational amplifier.

7. The output short detection circuit according to claim 6, characterized by The number of the fourth resistors between the first output end and the negative input end of the operational amplifier is the same as the number of the fourth resistors between the second output end and the positive input end of the operational amplifier.

8. The output short detection circuit according to any one of claims 1 to 4, characterized by, The sampling module comprises a fourth resistor, a fifth resistor, a sixth resistor and a transformer; One end of the fourth resistor is connected with the first output end, and the other end of the fourth resistor is connected with one end of the primary coil of the transformer; One end of the fifth resistor is connected with the second output end, and the other end of the fifth resistor is connected with the other end of the primary coil of the transformer; The sixth resistor is connected between two ends of the secondary coil of the transformer, and one end of the secondary coil of the transformer is grounded.

9. A charging short detection device characterized by comprising: The output short circuit detection circuit comprises a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor, a sixth capacitor, a seventh capacitor, an eighth capacitor, a ninth capacitor, a tenth capacitor, an eleventh capacitor, a twelfth capacitor, a thirteenth capacitor, a fourteenth capacitor, a fifteenth capacitor, a sixteenth capacitor, a seventeenth capacitor, an eighteenth capacitor, a nineteenth capacitor, a twentieth capacitor, a twenty-first capacitor, a twenty-second capacitor, a twenty-third capacitor, a twenty-fourth capacitor, a twenty-fifth capacitor, a twenty-sixth capacitor, a twenty-seventh capacitor, a twenty-eighth capacitor, a twenty-ninth capacitor, a thirtieth capacitor, a thirty-first capacitor, a thirty-second capacitor, a thirty-third capacitor, a thirty-fourth capacitor, a thirty-fifth capacitor, a thirty-sixth capacitor, a thirty-seventh capacitor, a thirty-eighth capacitor, a thirty-ninth capacitor, a fortieth capacitor, a forty-first capacitor, a forty-second capacitor, a forty-third capacitor, a forty-fourth capacitor, a forty-fifth capacitor, a forty-sixth capacitor, a forty-seventh capacitor, a forty-eighth capacitor, a forty-ninth capacitor, a fiftieth capacitor, a fifty-first capacitor, a fifty-second capacitor, a fifty-third capacitor, a fifty-fourth capacitor, a fifty-fifth capacitor, a fifty-sixth capacitor, a fifty-seventh capacitor, a fifty-eighth capacitor, a fifty-ninth capacitor, a sixtieth capacitor, a sixty-first capacitor, a sixty-second capacitor, a sixty-third capacitor, a sixty-fourth capacitor, a sixty-fifth capacitor, a sixty-sixth capacitor, a sixty-seventh capacitor, a sixty-eighth capacitor, a sixty-ninth capacitor, a seventieth capacitor, a seventy-first capacitor, a seventy-second capacitor, a seventy-third capacitor, a seventy-fourth capacitor, a seventy-fifth capacitor, a seventy-sixth capacitor, a seventy-seventh capacitor, a seventy-eighth capacitor, a seventy-ninth capacitor, an eightieth capacitor, a eighty-first capacitor, a eighty-second capacitor, a eighty-third capacitor, a eighty-fourth capacitor, a eighty-fifth capacitor, a eighty-sixth capacitor, a eighty-seventh capacitor, a eighty-eighth capacitor, a eighty-ninth capacitor, a ninetieth capacitor, a ninety-first capacitor, a ninety-second capacitor, a ninety-third capacitor, a 10. A charging device, characterized by ​

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