Charging pile short circuit detection circuit, short circuit detection device and alternating current charging pile

Abstract

The utility model discloses a charging pile short circuit detection circuit, a short circuit detection device and an AC charging pile, the circuit comprises a power supply input module, a short circuit detection module, a signal processing module and a control module, the power supply input module comprises resistors R1, R2, R3 and R4 and relays K1, K2, K3 and K4, and the short circuit detection module comprises a first amplification unit and a first filtering unit. The signal processing module comprises a second amplifying unit and a second filtering unit, the control module is electrically connected with the relays K1, K2, K3 and K4 and the output end of the second amplifying unit, and the control module is configured to control the relay K3 to be switched on, control the relays K1, K2 and K4 to be switched off, obtain first detection voltage from the second amplifying unit and send the first detection voltage to the second filtering unit; when the first detection voltage is greater than or equal to the first preset voltage value, a short-circuit signal is generated. According to the utility model, the short circuit condition between the live line and the zero line of the AC charging pile to the ground can be comprehensively detected, the detection error can be reduced, and the safety of the charging pile is improved.

Description

Technical Field

[0001] This utility model relates to the field of circuit testing technology, and in particular to a short circuit detection circuit, a short circuit detection device, and an AC charging pile. Background Technology

[0002] With the increasing popularity of electric vehicles, the safety of AC charging stations, as an important supporting facility, is receiving growing attention. AC charging stations are high-voltage electrical devices. After detecting and controlling charging information, they close the output relay and output power if charging conditions are met. However, existing AC charging stations are prone to short circuits between the live and neutral wires due to certain factors. If the relay closes when a short circuit occurs at the output of the AC charging station, the instantaneous high voltage and current could damage the charging station or even the vehicle, causing leakage and other problems, posing a significant safety hazard. Utility Model Content

[0003] The purpose of this utility model is to solve at least one of the technical problems existing in the prior art, and to provide a charging pile short circuit detection circuit, short circuit detection device and AC charging pile, which can not only comprehensively detect the short circuit between the live wire and neutral wire to ground of the AC charging pile, with a wide range of applications, but also reduce detection errors and improve the safety of the charging pile.

[0004] According to a first aspect of the present invention, a charging pile short-circuit detection circuit includes a power input module, a short-circuit detection module, a signal processing module, and a control module. The power input module includes resistors R1, R2, R3, and R4, and relays K1, K2, K3, and K4. Resistors R1, R2, R3, and R4, along with relays K3 and K4, are connected in series to the power voltage input terminal. One end of relay K1 is connected to terminal L1 of the charging pile, and the other end is connected between relay K3 and resistor R2. One end of relay K2 is connected to terminal N of the charging pile, and the other end is connected between relay K4 and resistor R2. Terminal PE of the charging pile is connected between resistors R3 and R4. The short-circuit detection module includes a first amplification unit and a second... A filtering unit is provided, with its input terminal electrically connected to the output terminal of the power input module and its output terminal electrically connected to the input terminal of the first amplification unit. The signal processing module includes a second amplification unit and a second filtering unit, with the input terminal of the second filtering unit electrically connected to the output terminal of the first amplification unit and its output terminal electrically connected to the input terminal of the second amplification unit. The control module is electrically connected to relays K1, K2, K3, and K4 and the output terminal of the second amplification unit, respectively. The control module is configured to: control relay K3 to close, control relays K1, K2, and K4 to open, obtain a first detection voltage from the second amplification unit, and generate a short-circuit signal when the first detection voltage is greater than or equal to a first preset voltage value.

[0005] According to some embodiments of the present invention, the control module is configured to: control the relays K3 and K4 to close, control the relays K1 and K2 to open, obtain a second detection voltage from the second amplification unit, and generate a short-circuit signal when the second detection voltage is greater than or equal to a second preset voltage value.

[0006] According to some embodiments of the present invention, the first amplification unit includes resistor R7, resistor R8 and operational amplifier OP1. The inverting input terminal of the operational amplifier OP1 is connected to one end of resistor R7 and one end of resistor R8, respectively. The other end of resistor R8 is connected to the output terminal of operational amplifier OP1, and the other end of resistor R7 is grounded.

[0007] According to some embodiments of the present invention, the first filter unit includes a resistor R5 and a capacitor C1. One end of the resistor R4 is connected to one end of the resistor R5. The non-inverting input terminal of the operational amplifier OP1 is connected to one end of the capacitor C1 and the connection point between the resistor R4 and the resistor R5. The other end of the resistor R5 and the other end of the capacitor C1 are respectively grounded.

[0008] According to some embodiments of the present invention, the first amplification unit further includes diode D1 and diode D2. The anode of diode D1 and the cathode of diode D2 are respectively connected to the non-inverting input terminal of the operational amplifier device OP1. The cathode of diode D1 is connected to the power supply voltage input terminal, and the anode of diode D2 is grounded.

[0009] According to some embodiments of the present invention, the second filter unit includes a resistor R9 and a capacitor C2. One end of the resistor R9 is connected to the other end of the resistor R8 and the output terminal of the operational amplifier OP1, and the other end is connected to one end of the capacitor C2. The other end of the capacitor C2 is grounded.

[0010] According to some embodiments of the present invention, the second amplification unit includes a resistor R6 and an operational amplifier OP2. The non-inverting input terminal of the operational amplifier OP2 is connected to one end of the capacitor C2 and the other end of the resistor R9, respectively. The inverting input terminal of the operational amplifier OP2 is connected to the output terminal of the operational amplifier OP2 and one end of the resistor R6, respectively.

[0011] According to some embodiments of the present invention, the control module includes an MCU controller, and the I / O interface of the MCU controller is connected to the other end of the resistor R6.

[0012] A short-circuit detection device according to a second aspect of the present invention includes a PCB circuit board and a charging pile short-circuit detection circuit as described in the first aspect, wherein the charging pile short-circuit detection circuit is disposed on the PCB circuit board.

[0013] An AC charging pile according to a third aspect of the present invention includes the short-circuit detection device described in the second aspect.

[0014] The charging pile short-circuit detection circuit, short-circuit detection device, and AC charging pile provided according to the embodiments of this utility model have at least the following beneficial effects:

[0015] In this embodiment, the charging pile short-circuit detection circuit includes a power input module, a short-circuit detection module, a signal processing module, and a control module. The power input module includes resistors R1, R2, R3, and R4, and relays K1, K2, K3, and K4. Resistors R1, R2, R3, and R4, along with relays K3 and K4, are connected in series to the power voltage input terminal. One end of relay K1 is connected to terminal L1 of the charging pile, and the other end is connected between relay K3 and resistor R2. One end of relay K2 is connected to terminal N of the charging pile, and the other end is connected between relay K4 and resistor R2. Terminal PE of the charging pile is connected between resistors R3 and R4. The short-circuit detection module includes a first amplifier. The system includes a power input module and a first filtering unit. The input terminal of the first filtering unit is electrically connected to the output terminal of the power input module, and the output terminal of the first filtering unit is electrically connected to the input terminal of the first amplification unit. The signal processing module includes a second amplification unit and a second filtering unit. The input terminal of the second filtering unit is electrically connected to the output terminal of the first amplification unit, and the output terminal of the second filtering unit is electrically connected to the input terminal of the second amplification unit. The control module is electrically connected to the relays K1, K2, K3, K4, and the output terminal of the second amplification unit. The control module is configured to: control the relay K3 to close, control the relays K1, K2, K4 to open, obtain a first detection voltage from the second amplification unit, and generate a short-circuit signal when the first detection voltage is greater than or equal to a first preset voltage value. This embodiment of the invention, through the cooperation of multiple relays and resistors in the power input module, can comprehensively detect short circuits between the live wire and neutral wire to ground in AC charging piles, and has a wide range of applications. Furthermore, the short-circuit detection module includes a first amplification unit and a first filtering unit, which can initially amplify and filter the detection signal output from the power input module to remove noise interference and improve signal quality. Simultaneously, the signal processing module further amplifies and filters the signal through a second amplification unit and a second filtering unit, helping to reduce detection errors. In addition, the control module precisely controls the closing and opening of the relay, achieving pre-detection of load short circuits before closing the output relay. When an abnormal voltage signal is detected, a short-circuit signal is generated to promptly disconnect the circuit, avoiding high-voltage, high-current surges caused by short circuits and improving the safety of the charging pile.

[0016] Other features and advantages of this invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained by means of the structures particularly pointed out in the description and the drawings. Attached Figure Description

[0017] The accompanying drawings are provided to further understand the technical solution of this utility model and constitute a part of the specification. They are used together with the embodiments of this utility model to explain the technical solution of this utility model, and do not constitute a limitation on the technical solution of this utility model.

[0018] The present invention will be further described below with reference to the accompanying drawings and embodiments;

[0019] Figure 1 This is a circuit diagram of the charging pile short-circuit detection circuit according to an embodiment of the present utility model;

[0020] Figure 2 This is an equivalent circuit diagram of a charging pile short-circuit detection circuit according to an embodiment of the present invention.

[0021] Figure 3 This is an equivalent circuit diagram of a charging pile short-circuit detection circuit according to another embodiment of the present invention.

[0022] The attached diagram is labeled as follows: power input module 100, short circuit detection module 200, signal processing module 300, and control module 400. Detailed Implementation

[0023] This section will describe in detail the specific embodiments of the present utility model. The preferred embodiments of the present utility model are shown in the accompanying drawings. The purpose of the drawings is to supplement the textual description with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present utility model, but they should not be construed as limiting the scope of protection of the present utility model.

[0024] In the description of this utility model, it should be understood that the directional descriptions, such as up, down, front, back, left, right, etc., indicate the directional or positional relationship based on the directional or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0025] In the description of this utility model, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. If "first" or "second" is used in the description, it is only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0026] In the description of this utility model, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.

[0027] With the increasing popularity of electric vehicles, the safety of AC charging stations, as an important supporting facility, is receiving growing attention. AC charging stations are high-voltage electrical devices. After detecting and controlling charging information, they close the output relay and output power if charging conditions are met. However, existing AC charging stations are prone to short circuits between the live and neutral wires due to certain factors. If the relay closes when a short circuit occurs at the output of the AC charging station, the instantaneous high voltage and current could damage the charging station or even the vehicle, causing leakage and other problems, posing a significant safety hazard.

[0028] Based on this, the present invention provides a charging pile short circuit detection circuit, a short circuit detection device, and an AC charging pile, which can not only comprehensively detect the short circuit between the live wire and neutral wire of the AC charging pile and ground, thus having a wide range of applications, but also reduce detection errors and improve the safety of the charging pile.

[0029] The embodiments of this utility model will be further described below with reference to the accompanying drawings.

[0030] Reference Figure 1The first aspect of this utility model provides a short-circuit detection circuit for a charging pile, including a power input module 100, a short-circuit detection module 200, a signal processing module 300, and a control module 400. The power input module 100 includes resistors R1, R2, R3, and R4, and relays K1, K2, K3, and K4. Resistors R1, R2, R3, and R4, and relays K3 and K4 are connected in series to the power supply voltage input terminal. One end of relay K1 is connected to the charging pile terminal L1, and the other end is connected between relay K3 and resistor R2. One end of relay K2 is connected to the charging pile terminal N, and the other end is connected between relay K4 and resistor R2. The charging pile terminal PE is connected between resistors R3 and R4. The short-circuit detection module 200 includes a first... The signal processing module 300 includes an amplification unit and a first filtering unit. The input terminal of the first filtering unit is electrically connected to the output terminal of the power input module 100, and the output terminal of the first filtering unit is electrically connected to the input terminal of the first amplification unit. The signal processing module 300 includes a second amplification unit and a second filtering unit. The input terminal of the second filtering unit is electrically connected to the output terminal of the first amplification unit, and the output terminal of the second filtering unit is electrically connected to the input terminal of the second amplification unit. The control module 400 is electrically connected to relays K1, K2, K3, K4 and the output terminal of the second amplification unit, respectively. The control module 400 is configured to: control relay K3 to close, control relays K1, K2, K4 to open, obtain a first detection voltage from the second amplification unit, and generate a short-circuit signal when the first detection voltage is greater than or equal to a first preset voltage value.

[0031] It is understandable that, such as Figure 1 As shown, in a single-phase charging pile circuit, to achieve accurate short-circuit detection, high-resistance resistors can be connected between each phase line. Specifically, a high-resistance resistor R1 is connected in series between the L1 line of the charging pile and the power supply voltage input terminal VCC; a high-resistance resistor R2 is connected in series between the L1 line and the N line; and a high-resistance resistor R3 is connected in series between the N line and the PE line. It should be understood that for a single-phase charging pile with only L1 and N phase inputs, when the relay is in the open state, the external power supply voltage of the VCC input circuit is divided by the voltage divider network composed of R1, R2, R3, and R4. The isolated DC source formed between VCC and GND ensures the safety and independence of the circuit. It should be noted that, apart from the charging pile short-circuit detection circuit of this embodiment, there is no other form of electrical connection between GND and PE, thereby effectively avoiding potential interference and leakage risks.

[0032] In some embodiments, resistors R1, R2, R3 and R4 can all be selected as 20kΩ resistors. After the charging gun is plugged into the on-board charger (OBC) interface of the electric vehicle, the control module 400 first controls the closed relay K3 and the open relays K1, K2 and K4.

[0033] like Figure 2 As shown, Figure 2 This is the equivalent circuit for the charging pile short circuit detection circuit. It should be noted that since there is no unified standard range for the impedance of the vehicle OBC, the threshold for judging impedance abnormality can be set when Z1 is less than 10kΩ and Z2 and Z3 are less than 500kΩ. Then, the voltage obtained from the second amplification unit can be calculated as follows: VCC / (R1+(R2 / / Z1+Z2) / / Z3+R4+R5)*R5=VCC / (R1+Z2 / / Z3+R4+R5)*R5=2 / 31*VCC.

[0034] Where Z1 represents the impedance between the live wire (L) and neutral wire (N) of the vehicle OBC, Z2 represents the impedance between the neutral wire (N) and protective earth wire (PE) of the vehicle OBC, Z3 represents the impedance between the live wire (L) and protective earth wire (PE) of the vehicle OBC, and (R2 / / Z1+Z2) / / Z3 represents the impedance between LN and PE.

[0035] Furthermore, the first preset voltage value can be set to 2 / 31*VCC. When the first detection voltage obtained by the control module 400 from the second amplification unit is greater than or equal to 2 / 31*VCC, it indicates that the impedance of L and N to ground is abnormal. Therefore, the control module 400 determines that a short circuit has occurred between L and N to ground and generates a short-circuit signal. Conversely, when the first detection voltage obtained by the control module 400 from the second amplification unit is less than 2 / 31*VCC, it indicates that the impedance of L and N to ground is normal. Therefore, the control module 400 determines that no short circuit has occurred between L and N to ground.

[0036] According to the charging pile short-circuit detection circuit provided by this utility model, through the cooperation of multiple relays and resistors in the power input module 100, it can comprehensively detect short circuits between the live wire and neutral wire to ground in AC charging piles, with a wide range of applications. Furthermore, the short-circuit detection module 200 includes a first amplification unit and a first filtering unit, which can initially amplify and filter the detection signal output by the power input module 100, removing noise interference and improving signal quality. Simultaneously, the signal processing module 300 further amplifies and filters the signal through a second amplification unit and a second filtering unit, helping to reduce detection errors. In addition, the control module 400, by precisely controlling the closing and opening of the relays, achieves pre-detection of load short circuits before closing the output relays. When an abnormal voltage signal is detected, a short-circuit signal can be generated to promptly cut off the circuit, avoiding high-voltage and high-current surges caused by short circuits and improving the safety of the charging pile.

[0037] Reference Figure 1 In the charging pile short-circuit detection circuit provided in some embodiments of this utility model, the control module 400 is configured to: control relays K3 and K4 to close, control relays K1 and K2 to open, obtain a second detection voltage from the second amplification unit, and generate a short-circuit signal when the second detection voltage is greater than or equal to a second preset voltage value. It can be understood that, if it is determined that no short circuit has occurred between L and N and ground, the control module 400 controls relays K3 and K4 to close and controls relays K1 and K2 to open.

[0038] Specifically, such as Figure 3 As shown, Figure 3 This is the equivalent circuit for the charging pile short-circuit detection circuit. The voltage obtained from the second amplification unit can be calculated as follows: VCC / (R1+(R2 / / Z1+R3 / / Z2) / / Z3+R4+R5)*R5=VCC / (R1+R2 / / Z1+R3+R4+R5)*R5 =(R2+Z1)*VCC / (4*R2+5*Z1))=3 / 13*VCC.

[0039] Where Z1 represents the impedance between the live wire (L) and the neutral wire (N) of the vehicle OBC, Z2 represents the impedance between the neutral wire (N) and the protective earth wire (PE) of the vehicle OBC, and Z3 represents the impedance between the live wire (L) and the protective earth wire (PE) of the vehicle OBC.

[0040] Furthermore, the second preset voltage value can be set to 3 / 13*VCC. When the second detection voltage obtained by the control module 400 from the second amplification unit is greater than or equal to 3 / 13*VCC, it indicates that the impedance between L and N is abnormal. Therefore, the control module 400 determines that a short circuit has occurred between L and N and generates a short circuit signal. Conversely, when the second detection voltage obtained by the control module 400 from the second amplification unit is less than 3 / 13*VCC, it indicates that the impedance between L and N is normal. Therefore, the control module 400 determines that no short circuit has occurred between L and N.

[0041] In some embodiments, if it is determined that there is no short circuit between L and N to ground or between L and N, the control module 400 controls relays K3 and K4 to open. Subsequently, the charging pile communicates and hands-on with the OBC for control guidance. When the communication is successfully established and conditions permit, the control module 400 closes relays K1 and K2, thereby starting to charge the electric vehicle.

[0042] Reference Figure 1 In the charging pile short-circuit detection circuit provided in some embodiments of this utility model, the first amplification unit includes resistors R7 and R8 and operational amplifier OP1. The inverting input terminal of operational amplifier OP1 is connected to one end of resistor R7 and one end of resistor R8, respectively. The other end of resistor R8 is connected to the output terminal of operational amplifier OP1, and the other end of resistor R7 is grounded. It should be noted that resistors R7 and R8, together with operational amplifier OP1, form a non-inverting amplifier. The non-inverting input terminal of operational amplifier OP1 receives the detection voltage signal from the power input module 100, amplifies it, and outputs it. At the same time, the input terminal potential is stabilized by grounding resistor R7, and resistor R8 is connected to the output terminal to form feedback. The amplification factor k can be calculated based on the resistance values ​​of resistors R7 and R8: k = 1 + R8 / R7, thereby ensuring accurate signal amplification and improving the accuracy of subsequent processing. Furthermore, when resistor R7 is unconnected, operational amplifier OP1 acts as a voltage follower. At this time, the output voltage is consistent with the input voltage, realizing signal buffering and isolation, ensuring that the signal source is not affected by the load, and providing stable signal drive for subsequent circuits.

[0043] Reference Figure 1In the charging pile short-circuit detection circuit provided in some embodiments of this utility model, the first filtering unit includes a resistor R5 and a capacitor C1. One end of resistor R4 is connected to one end of resistor R5. The non-inverting input terminal of operational amplifier OP1 is connected to one end of capacitor C1 and the connection point between resistor R4 and resistor R5. The other ends of resistor R5 and capacitor C1 are grounded. It can be understood that the connection point between resistor R4 and resistor R5 can be the sampling point A of the detection voltage. After VCC is divided by resistors R4 and R5, the detection voltage signal output at sampling point A is a DC signal, which is then output to the non-inverting input terminal of operational amplifier OP1. It should be understood that when the charging gun is connected to the car charging port, the on-board electronic equipment and charging system may generate electromagnetic interference. This interference may be introduced into the charging circuit through L1, N, or PE lines, affecting charging safety and stability. Therefore, capacitor C1 and the voltage divider resistor R5 in the circuit can jointly form a low-pass filter to filter out external high-frequency interference signals, suppress the intrusion of interference signals, and improve the stability and safety of the charging pile short-circuit detection circuit.

[0044] Reference Figure 1 In the charging pile short-circuit detection circuit provided in some embodiments of this utility model, the first amplification unit further includes diodes D1 and D2. The anode of diode D1 and the cathode of diode D2 are respectively connected to the non-inverting input terminal of operational amplifier OP1. The cathode of diode D1 is connected to the power supply voltage input terminal, and the anode of diode D2 is grounded. It should be noted that, in order to prevent damage to operational amplifier OP1 caused by relay K3 or K4 failing to disconnect effectively or by the accidental introduction of a high-voltage signal, diodes D1 and D2 are added to the non-inverting input terminal of operational amplifier OP1 for voltage clamping. When the circuit is working normally, D1 and D2 are cut off, and signal transmission is not affected; however, when an abnormal high voltage occurs, D1 and D2 conduct, clamping the input voltage within a safe range and protecting operational amplifier OP1 and its subsequent circuits to ensure stable operation.

[0045] Reference Figure 1 In the charging pile short-circuit detection circuit provided in some embodiments of this utility model, the second filtering unit includes a resistor R9 and a capacitor C2. One end of the resistor R9 is connected to the other end of the resistor R8 and the output terminal of the operational amplifier OP1, and the other end is connected to one end of the capacitor C2, with the other end of the capacitor C2 grounded. It is understood that the resistor R9 and capacitor C2 together constitute a low-pass filter, and the cutoff frequency f can be calculated as follows: f = 1 / (2πRC), where R is the resistance value of resistor R9 and C is the capacitance value of capacitor C2. This utility model does not limit the specific values. In one embodiment, the cutoff frequency f can be set below 5Hz, which can effectively suppress high-frequency interference at the vehicle end and ensure stable signal transmission.

[0046] Reference Figure 1In the charging pile short-circuit detection circuit provided in some embodiments of this utility model, the second amplification unit includes a resistor R6 and an operational amplifier OP2. The non-inverting input terminal of the operational amplifier OP2 is connected to one end of the capacitor C2 and the other end of the resistor R9, respectively. The inverting input terminal of the operational amplifier OP2 is connected to the output terminal of the operational amplifier OP2 and one end of the resistor R6, respectively. It should be noted that the non-inverting input terminal of the operational amplifier OP2 is connected to one end of the capacitor C2 and the other end of the resistor R9 to receive the filtered detection voltage signal. The inverting input terminal of the operational amplifier OP2 is connected to its own output terminal and one end of the resistor R6 to form a negative feedback path, stabilize the amplification factor and improve the circuit stability, and is connected to the subsequent circuit through the resistor R6. It should be understood that since the low-pass filter connected to the non-inverting input of the operational amplifier OP2 consists of resistor R9 and capacitor C2, if the resistance value of resistor R9 or the capacitance value of capacitor C2 is too large, it is easy to reduce the accuracy of the ADC sampling signal, that is, reduce the accuracy of the detected voltage signal. Therefore, the output of the low-pass filter connected to the operational amplifier OP2 through resistor R9 and capacitor C2 can play the role of impedance matching. At this time, the operational amplifier OP2 acts as a buffer, which can increase the sampling accuracy of the ADC.

[0047] Reference Figure 1 In some embodiments of the charging pile short-circuit detection circuit provided by this utility model, the control module 400 includes an MCU controller, and the I / O interface of the MCU controller is connected to the other end of the resistor R6. It can be understood that the I / O interface of the MCU controller can be an input pin, which, through connection to the other end of the resistor R6, obtains the detection voltage signal after noise interference elimination from the second amplification unit. Furthermore, the I / O interface of the MCU controller can also be an output pin, connected to the coil of the relay via a driving circuit (such as a transistor, optocoupler, etc.). Figure 1 (not shown in the image), and then, based on the preset logic and the detected signal (such as the detected voltage signal), the control signal line outputs a high level or a low level to drive the relay coil to be energized or de-energized, thereby controlling the closing or opening of the relay contacts and realizing the on / off control of the charging pile output circuit.

[0048] A second aspect of this utility model provides a short-circuit detection device, including a PCB circuit board and the charging pile short-circuit detection circuit described in the first aspect, wherein the charging pile short-circuit detection circuit is disposed on the PCB circuit board.

[0049] A third aspect of this utility model provides an AC charging pile, including the short-circuit detection device described in the second aspect.

[0050] The embodiments of the present utility model have been described in detail above with reference to the accompanying drawings. However, the present utility model is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present utility model.

Claims

1. A short-circuit detection circuit for a charging pile, characterized in that, include: The power input module includes resistors (R1), (R2), (R3), and (R4) and relays (K1), (K2), (K3), and (K4). The resistors (R1), (R2), (R3), and (R4) and the relays (K3) and (K4) are connected in series to the power voltage input terminal. One end of the relay (K1) is connected to the terminal (L1) of the charging pile, and the other end is connected between the relay (K3) and the resistor (R2). One end of the relay (K2) is connected to the terminal (N) of the charging pile, and the other end is connected between the relay (K4) and the resistor (R2). The terminal (PE) of the charging pile is connected between the resistors (R3) and (R4). The short-circuit detection module includes a first amplification unit and a first filtering unit. The input terminal of the first filtering unit is electrically connected to the output terminal of the power input module, and the output terminal of the first filtering unit is electrically connected to the input terminal of the first amplification unit. The signal processing module includes a second amplification unit and a second filtering unit. The input terminal of the second filtering unit is electrically connected to the output terminal of the first amplification unit, and the output terminal of the second filtering unit is electrically connected to the input terminal of the second amplification unit. The control module is electrically connected to the output terminals of the relays (K1), (K2), (K3), (K4) and the second amplification unit, respectively. The control module is configured to: control the relay (K3) to close, control the relays (K1), (K2), (K4) to open, obtain a first detection voltage from the second amplification unit, and generate a short-circuit signal when the first detection voltage is greater than or equal to a first preset voltage value.

2. The charging pile short-circuit detection circuit according to claim 1, characterized in that, The control module is configured to: control the relays (K3) and (K4) to close, control the relays (K1) and (K2) to open, obtain a second detection voltage from the second amplification unit, and generate a short-circuit signal when the second detection voltage is greater than or equal to a second preset voltage value.

3. The charging pile short-circuit detection circuit according to claim 2, characterized in that, The first amplification unit includes resistors (R7), resistors (R8), and an operational amplifier (OP1). The inverting input terminal of the operational amplifier (OP1) is connected to one end of resistor (R7) and one end of resistor (R8), respectively. The other end of resistor (R8) is connected to the output terminal of the operational amplifier (OP1), and the other end of resistor (R7) is grounded.

4. The charging pile short-circuit detection circuit according to claim 3, characterized in that, The first filter unit includes a resistor (R5) and a capacitor (C1). One end of the resistor (R4) is connected to one end of the resistor (R5). The non-inverting input terminal of the operational amplifier (OP1) is connected to one end of the capacitor (C1) and the connection point between the resistor (R4) and the resistor (R5). The other end of the resistor (R5) and the other end of the capacitor (C1) are grounded.

5. The charging pile short-circuit detection circuit according to claim 4, characterized in that, The first amplification unit further includes diodes (D1) and (D2). The anode of diode (D1) and the cathode of diode (D2) are respectively connected to the non-inverting input terminal of the operational amplifier device (OP1). The cathode of diode (D1) is connected to the power supply voltage input terminal, and the anode of diode (D2) is grounded.

6. The charging pile short-circuit detection circuit according to claim 3, characterized in that, The second filter unit includes a resistor (R9) and a capacitor (C2). One end of the resistor (R9) is connected to the other end of the resistor (R8) and the output terminal of the operational amplifier (OP1), and the other end is connected to one end of the capacitor (C2). The other end of the capacitor (C2) is grounded.

7. The charging pile short-circuit detection circuit according to claim 6, characterized in that, The second amplification unit includes a resistor (R6) and an operational amplifier (OP2). The non-inverting input terminal of the operational amplifier (OP2) is connected to one end of the capacitor (C2) and the other end of the resistor (R9), respectively. The inverting input terminal of the operational amplifier (OP2) is connected to the output terminal of the operational amplifier (OP2) and one end of the resistor (R6), respectively.

8. The charging pile short-circuit detection circuit according to claim 7, characterized in that, The control module includes an MCU controller, whose I / O interface is connected to the other end of the resistor (R6).

9. A short-circuit detection device, characterized in that, It includes a PCB circuit board and a charging pile short-circuit detection circuit as described in any one of claims 1 to 8, wherein the charging pile short-circuit detection circuit is disposed on the PCB circuit board.

10. An AC charging pile, characterized in that, Includes the short-circuit detection device as described in claim 9.

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