Charging pile output fault detection circuit and detection method

Abstract

The invention discloses a charging pile output fault detection circuit and detection method.The charging pile output fault detection circuit is used for being connected between a three-phase four-wire inlet wire and a charging output loop and comprises an output short circuit detection and adhesion detection circuit and a microcontroller; the output short circuit detection and adhesion detection circuit comprises four relays, four input ends, four charging output ends, four feedback signal output ends and a driving end, the input ends are connected with the relays in a one-to-one correspondence mode, and the input ends are connected with all phase lines of a three-phase four-line incoming line and a neutral N line respectively; the relay connected with the neutral N line is also connected with the driving end, and the charging output end is connected with the charging output loop; the signal input end of the microcontroller is connected with the feedback signal output end, and the driving signal output end of the microcontroller is connected with the driving end. The three-phase alternating current charging pile output short circuit detection and adhesion detection functions can be realized at the same time.

Description

Technical Field

[0001] The invention relates to a charging pile output fault detection circuit and a detection method, belonging to the technical field of charging piles. Background Art

[0002] With the development of new energy vehicles, the capacity of power batteries has increased significantly, and the power and time required for charging have also increased accordingly. Traditional AC charging piles of 7kW or even 3.5kW can no longer meet the user's home needs, so AC fast charging has gradually entered the user's field of vision. AC fast charging is mainly a three-phase AC charging pile with a charging power of up to 22kW. Its charging line voltage is high and the charging current is large. Therefore, the safety management of charging piles is particularly important, especially the short-circuit detection of the output port and the adhesion detection of the relay.

[0003] Before starting charging, the three-phase AC charging pile must ensure that there is no short circuit fault at the output port, otherwise charging should not be started. And the status of the main circuit relay must be identified in time before, during and after charging to avoid starting charging or touching the output circuit when the relay is stuck, which may cause an accident.

[0004] At present, the main method for detecting short circuits in the output of AC charging piles on the market is the signal injection detection method, which applies a voltage source and a feedback circuit to the output circuit through a relay or an isolated power supply, and then the detection circuit detects the feedback signal. It determines whether the output line is currently in a short circuit state based on the feedback signal. This method has certain risks and requires a reliable and complex interlocking circuit, otherwise it is easy to cause serious damage to the circuit board. In addition, the judgment results of this method are relatively general and cannot clearly locate the short circuit loop. If you want to locate a specific short circuit loop, the circuit complexity will increase greatly and the cost will be very high.

[0005] Relay output adhesion detection generally uses relay auxiliary contacts or output voltage recovery. The former is costly, and the latter cannot determine the fault state of single contact adhesion. Summary of the invention

[0006] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a charging pile output fault detection circuit, which can simultaneously realize the functions of three-phase AC charging pile output short circuit detection and adhesion detection.

[0007] In order to solve the above technical problems, the technical solution of the present invention is: a charging pile output fault detection circuit, which is used to be connected between a three-phase four-wire incoming line and a charging output circuit, comprising:

[0008] An output short circuit detection and adhesion detection circuit, the output short circuit detection and adhesion detection circuit comprising four relays, four input terminals, four charging output terminals, four feedback signal output terminals and a driving terminal, the input terminals are connected to the relays in a one-to-one correspondence, and the input terminals are respectively connected to each phase line and a neutral N line of a three-phase four-wire incoming line, the relay connected to the neutral N line is also connected to the driving terminal, and the charging output terminal is connected to the charging output circuit;

[0009] A microcontroller, wherein the signal input terminal of the microcontroller is connected to the feedback signal output terminal, and the drive signal output terminal of the microcontroller is connected to the drive terminal; wherein,

[0010] When the output short circuit detection and adhesion detection circuit is powered on, the output short circuit detection and adhesion detection circuit outputs corresponding feedback signals through four feedback signal output terminals according to the actual disconnection and closing conditions of each relay and transmits them to the microcontroller. The microcontroller determines the adhesion condition of each relay according to the received feedback signals and sends a driving signal to the driving end after determining that each relay does not have a adhesion fault to control the relay connected to the neutral N line to be temporarily closed and continue to determine the output line short circuit condition corresponding to each charging output terminal according to the received feedback signals during the temporary closure period.

[0011] Furthermore, after the microcontroller determines that a relay has a sticking fault based on the received feedback signal, the microcontroller terminates the current charging process, sends a fault signal, and stops the operation of the charging pile.

[0012] Furthermore, after the microcontroller determines that a short circuit fault exists in the output line corresponding to the charging output terminal according to the received feedback signal, the microcontroller terminates the current charging process, sends a fault signal, and stops the operation of the charging pile.

[0013] Furthermore, the feedback signal includes one of a low level, a high level and a PWM waveform, and four feedback signals constitute a state code.

[0014] Furthermore, the relays are respectively a first relay, a second relay, a third relay and a fourth relay, the three-phase four-wire incoming line includes an A phase line, a B phase line, a C phase line and a neutral N line, the first relay is connected to the A phase line of the three-phase four-wire incoming line, the second relay is connected to the B phase line of the three-phase four-wire incoming line, the third relay is connected to the C phase line of the three-phase four-wire incoming line, and the fourth relay is connected to the neutral N line of the three-phase four-wire incoming line.

[0015] Further, the output short circuit detection and adhesion detection circuit also includes a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a first diode, a second diode, a third diode, a fourth diode, a fifth diode, a sixth diode, a first optical coupler, a second optical coupler, a third optical coupler, a fourth optical coupler, a fifth optical coupler and a sixth optical coupler; wherein,

[0016] The four input terminals are respectively a first input terminal, a second input terminal, a third input terminal and a fourth input terminal;

[0017] The four charging output terminals are respectively a first charging output terminal, a second charging output terminal, a third charging output terminal and a fourth charging output terminal;

[0018] The four feedback signal output terminals are respectively a first feedback signal output terminal, a second feedback signal output terminal, a third feedback signal output terminal, and a fourth feedback signal output terminal;

[0019] The A phase line is connected to the first input terminal, the first input terminal is connected to pin 2 of the first relay and pin 1 of the first resistor, pin 2 of the first resistor is connected to the cathode of the first diode, the anode of the first diode is connected to pin K of the first optocoupler, pin A of the first optocoupler is connected to pin 1 of the first relay and pin 1 of the fourth resistor, and then to the first charging output terminal;

[0020] The B phase line is connected to the second input terminal, the second input terminal is connected to pin 2 of the second relay and pin 1 of the second resistor, pin 2 of the second resistor is connected to the cathode of the second diode, the anode of the second diode is connected to pin K of the second optocoupler, pin A of the second optocoupler is connected to pin 1 of the second relay and pin 1 of the fifth resistor, and then connected to the second charging output terminal;

[0021] The C phase line is connected to the third input terminal, the third input terminal is connected to pin 2 of the third relay and pin 1 of the third resistor, pin 2 of the third resistor is connected to the cathode of the third diode, the anode of the third diode is connected to pin K of the third optocoupler, pin A of the third optocoupler is connected to pin 1 of the third relay and pin 1 of the sixth resistor, and then connected to the third charging output terminal;

[0022] The neutral N line is connected to the fourth input terminal, the fourth input terminal is connected to the 2nd pin of the fourth relay, the 1st pin of the fourth relay is connected to the A pin of the sixth optocoupler, the A pin of the fifth optocoupler, the A pin of the fourth optocoupler, the cathode of the sixth diode, the cathode of the fifth diode, and the cathode of the fourth diode, and then connected to the fourth charging output terminal;

[0023] The driving end is connected to the 6th foot of the fourth relay;

[0024] The C pin of the first optical coupler is connected to the C pin of the second optical coupler, the C pin of the third optical coupler, and then connected to the first charging output terminal;

[0025] Pin 2 of the fourth resistor is connected to the anode of the fourth diode and the K pin of the fourth optical coupler; the C pin of the fourth optical coupler is connected to the second charging output terminal;

[0026] Pin 2 of the fifth resistor is connected to the anode of the fifth diode and pin K of the fifth optocoupler; pin C of the fifth optocoupler is connected to the third charging output terminal;

[0027] The 2nd pin of the sixth resistor is connected to the anode of the sixth diode and the K pin of the sixth optocoupler; the C pin of the sixth optocoupler is connected to the fourth charging output terminal;

[0028] The E pin of the first optocoupler is connected to the E pin of the second optocoupler, the E pin of the third optocoupler, the E pin of the fourth optocoupler, the E pin of the fifth optocoupler, and the E pin of the sixth optocoupler as a reference ground.

[0029] The present invention also provides a detection method for a charging pile output fault detection circuit, the method comprising the following steps:

[0030] When the output short circuit detection and adhesion detection circuit is powered on, the output short circuit detection and adhesion detection circuit outputs corresponding feedback signals through four feedback signal output terminals according to the actual disconnection and closing conditions of each relay and transmits them to the microcontroller. The microcontroller determines the adhesion condition of each relay according to the received feedback signals and sends a driving signal to the driving end after determining that each relay does not have a adhesion fault to control the relay connected to the neutral N line to close temporarily and continue to determine the output line short circuit condition corresponding to each charging output terminal according to the received feedback signals during the short closing period.

[0031] After adopting the above technical solution, after the three-phase four-wire incoming line is connected, the output short-circuit detection and adhesion detection circuit generates a four-bit status code with a code value range of 0000~FFFF. The status code is output to the microcontroller. The microcontroller uses the internally stored code value-fault comparison table to compare and analyze whether there is a adhesion fault and which line the fault occurs in based on the feedback signal. If a adhesion fault is detected, the microcontroller will terminate the current charging process, send a fault signal, and stop the charging pile to notify maintenance.

[0032] If the possibility of adhesion fault in the circuit is eliminated, the microcontroller sends a drive signal to the output short circuit detection and adhesion detection circuit to control the fourth relay to temporarily close, and continues to compare and analyze whether there is an output short circuit fault and in which circuit the fault occurs according to the stored code value-fault comparison table. If an output short circuit fault is detected, the microcontroller will terminate the current charging process, send a fault signal, and stop the charging pile to notify maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a principle block diagram of the charging pile output fault detection circuit of the present invention;

[0034] Figure 2 It is a circuit connection diagram of the output short circuit detection and adhesion detection circuit of the present invention. DETAILED DESCRIPTION

[0035] In order to make the contents of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments in conjunction with the accompanying drawings.

[0036] like Figure 1 , 2 As shown, a charging pile output fault detection circuit is used to detect whether the charging output is short-circuited before charging and whether the relay is sticking during the whole charging process, which fully guarantees the operation safety and convenience of maintenance and repair of the charging pile. It is used to connect between the three-phase four-wire incoming line 2 and the charging output circuit 4, including:

[0037] Output short circuit detection and adhesion detection circuit 11, the output short circuit detection and adhesion detection circuit 11 includes four relays, four input terminals, four charging output terminals, four feedback signal output terminals and a driving terminal 1i, the input terminals are connected to the relays one by one, and the input terminals are respectively connected to each phase line and the neutral N line of the three-phase four-wire incoming line 2, the relay connected to the neutral N line is also connected to the driving terminal 1i, and the charging output terminal is connected to the charging output circuit 4;

[0038] The microcontroller 3, the signal input terminal of the microcontroller 3 is connected to the feedback signal output terminal, and the drive signal output terminal of the microcontroller 3 is connected to the drive terminal 1i; wherein,

[0039] When the output short circuit detection and adhesion detection circuit 11 is powered on, the output short circuit detection and adhesion detection circuit 11 outputs corresponding feedback signals through four feedback signal output terminals according to the actual disconnection and closing conditions of each relay and transmits them to the microcontroller 3. The microcontroller 3 determines the adhesion condition of each relay according to the received feedback signals and sends a driving signal to the driving terminal 1i after determining that there is no adhesion fault in each relay to control the relay connected to the neutral N line to close temporarily and continue to determine the output line short circuit condition corresponding to each charging output terminal according to the received feedback signals during the short closing period.

[0040] The charging output circuit 4 is a prior art on the charging pile and will not be described in detail in this embodiment.

[0041] Specifically, after the microcontroller 3 determines that the relay has a sticking fault according to the received feedback signal, the microcontroller 3 terminates the current charging process, sends a fault signal, and stops the operation of the charging pile.

[0042] Specifically, after the microcontroller 3 determines that a short circuit fault exists in the output line corresponding to the charging output terminal according to the received feedback signal, the microcontroller 3 terminates the current charging process, sends a fault signal, and stops the operation of the charging pile.

[0043] Specifically, Figure 1 , 2As shown, the relays are respectively a first relay K1, a second relay K2, a third relay K3 and a fourth relay K4, the three-phase four-wire incoming line 2 includes an A phase line, a B phase line, a C phase line and a neutral N line, the first relay K1 is connected to the A phase line of the three-phase four-wire incoming line 2, the second relay K2 is connected to the B phase line of the three-phase four-wire incoming line 2, the third relay K3 is connected to the C phase line of the three-phase four-wire incoming line 2, and the fourth relay K4 is connected to the neutral N line of the three-phase four-wire incoming line 2.

[0044] Specifically, Figure 2 As shown, the output short circuit detection and adhesion detection circuit 11 also includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a first diode D1, a second diode D2, a third diode D3, a fourth diode D4, a fifth diode D5, a sixth diode D6, a first optical coupler U1, a second optical coupler U2, a third optical coupler U3, a fourth optical coupler U4, a fifth optical coupler U5 and a sixth optical coupler U6; wherein,

[0045] The four input terminals are respectively a first input terminal 1a, a second input terminal 1b, a third input terminal 1c and a fourth input terminal 1d;

[0046] The four charging output terminals are respectively a first charging output terminal 1j, a second charging output terminal 1k, a third charging output terminal 1l and a fourth charging output terminal 1m;

[0047] The four feedback signal output terminals are respectively a first feedback signal output terminal 1e, a second feedback signal output terminal 1f, a third feedback signal output terminal 1g, and a fourth feedback signal output terminal 1h;

[0048] The A phase line is connected to the first input terminal 1a, the first input terminal 1a is connected to the 2nd pin of the first relay K1 and the 1st pin of the first resistor R1, the 2nd pin of the first resistor R1 is connected to the cathode of the first diode D1, the anode of the first diode D1 is connected to the K pin of the first optocoupler U1, the A pin of the first optocoupler U1 is connected to the 1st pin of the first relay K1 and the 1st pin of the fourth resistor R4, and then connected to the first charging output terminal 1j;

[0049] The B phase line is connected to the second input terminal 1b, the second input terminal 1b is connected to the 2nd pin of the second relay K2 and the 1st pin of the second resistor R2, the 2nd pin of the second resistor R2 is connected to the cathode of the second diode D2, the anode of the second diode D2 is connected to the Kth pin of the second optocoupler U2, the Ath pin of the second optocoupler U2 is connected to the 1st pin of the second relay K2 and the 1st pin of the fifth resistor R5, and then connected to the second charging output terminal 1k;

[0050] The C phase line is connected to the third input terminal 1c, the third input terminal 1c is connected to the 2nd pin of the third relay K3 and the 1st pin of the third resistor R3, the 2nd pin of the third resistor R3 is connected to the cathode of the third diode D3, the anode of the third diode D3 is connected to the K pin of the third optical coupler U3, the A pin of the third optical coupler U3 is connected to the 1st pin of the third relay K3 and the 1st pin of the sixth resistor R6, and then connected to the third charging output terminal 11;

[0051] The neutral N line is connected to the fourth input terminal 1d, the fourth input terminal 1d is connected to the 2nd pin of the fourth relay K4, the 1st pin of the fourth relay K4 is connected to the A pin of the sixth optocoupler U6, the A pin of the fifth optocoupler U5, the A pin of the fourth optocoupler U4, the cathode of the sixth diode D6, the cathode of the fifth diode D5, the cathode of the fourth diode D4, and then connected to the fourth charging output terminal 1m;

[0052] The driving terminal 1i is connected to the 6th foot of the fourth relay K4;

[0053] The C pin of the first optical coupler U1 is connected to the C pin of the second optical coupler U2 and the C pin of the third optical coupler U3, and then connected to the first charging output terminal 1e;

[0054] Pin 2 of the fourth resistor R4 is connected to the anode of the fourth diode D4 and the pin K of the fourth optical coupler U4; the pin C of the fourth optical coupler U4 is connected to the second charging output terminal 1f;

[0055] The 2nd pin of the fifth resistor R5 is connected to the anode of the fifth diode D5 and the K pin of the fifth optical coupler U5; the C pin of the fifth optical coupler U5 is connected to the third charging output terminal 1g;

[0056] The 2nd pin of the sixth resistor R6 is connected to the anode of the sixth diode D6 and the K pin of the sixth optical coupler U6; the C pin of the sixth optical coupler U6 is connected to the fourth charging output terminal 1m;

[0057] The E pin of the first optocoupler U1 is connected to the E pin of the second optocoupler U2 , the E pin of the third optocoupler U3 , the E pin of the fourth optocoupler U4 , the E pin of the fifth optocoupler U5 , and the E pin of the sixth optocoupler U6 as a reference ground.

[0058] In this embodiment, the feedback signal includes one of a low level, a high level and a PWM waveform, and four feedback signals constitute a state code; specifically, the output short circuit detection and adhesion detection circuit 11 will continuously output four feedback signals SIG_1, SIG_2, SIG_3, and SIG_4 after power-on, and each feedback signal includes three states: low level (represented by 0), high level (represented by 1), and PWM waveform (represented by F). The states of the four feedback signals are recorded in a state code: 0000~FFFF.

[0059] When the first relay K1, the second relay K2, the third relay K3, and the fourth relay K4 are all disconnected, the status code is 1111. Accordingly, closing any number of relays will change the status code. For example, when the first relay K1 is closed and the second relay K2, the third relay K3, and the fourth relay K4 are disconnected, the status code becomes F1FF. The microcontroller 3 determines whether there is an output relay adhesion fault and which circuit the fault occurs in by analyzing the status code value and combining it with the current working status of the charging pile. The specific code value-relay status comparison table is shown in the following table:

[0060] Code value Relay Status 1 1 1 1 All gates F 1F F Phase A is closed FF 1F Phase B is closed FFF 1 Phase C is closed 0F FF N phase closing FFFF Any two phases closed 1F FF At least three phases closed

[0061] When the adhesion test is qualified, the microcontroller 3 controls the fourth relay K4 of the N_in line to close briefly before charging, during which the status code is read to analyze whether there is an output short circuit fault and which circuit or circuits the fault occurs in. The specific code value-fault comparison table is shown in the following table:

[0062]

[0063]

[0064] In particular, there are some fault states where the status codes are the same. For example, in the table above, the corresponding code values ​​of multiple faults are 0FFF. In fact, the PWM waveforms represented by F are different in timing. In this case, you only need to sample multiple PWM waveforms synchronously and take several bits to determine their binary values. The two underlined F It means that their binary values ​​are the same. Based on this information, the faults corresponding to the same code value can be distinguished.

[0065] This embodiment implements a simple optocoupler, diode and resistor, combined with a simple query of the configured code value-fault comparison table, which can locate the output short circuit fault and adhesion fault of the three-phase AC charging pile in detail and completely. It does not require an additional low-voltage DC source and a complex interlocking protection circuit, nor does it require expensive relays and precision sampling circuits, making the entire circuit simple and reliable.

[0066] In this embodiment, the first resistor R1, the second resistor R2, the third resistor R3, the fourth resistor R4, the fifth resistor R5, and the sixth resistor R6 should preferably be power resistors with a package size of 2512 and a resistance of 510k ohms; the first diode D1, the second diode D2, the third diode D3, the fourth diode D4, the fifth diode D5, and the sixth diode D6 should preferably be rectifier diodes with a reverse withstand voltage greater than 1kV; the first optocoupler U1, the second optocoupler U2, the third optocoupler U3, the fourth optocoupler U4, the fifth optocoupler U5, and the sixth optocoupler U6 should preferably be DC optocouplers with a current transfer ratio greater than 100%.

[0067] Specifically: after the three-phase four-wire incoming line 2 is connected to work, the output short-circuit detection and adhesion detection circuit 11 generates a four-bit status code with a code value range of 0000~FFFF. The status code is output to the microcontroller 3. The microcontroller 3 compares and analyzes whether there is a adhesion fault and which line the fault occurs in according to the stored code value-fault comparison table; if a adhesion fault is detected, the microcontroller 3 will terminate the current charging process, send a fault signal, stop the operation of the charging pile to notify maintenance.

[0068] After eliminating the possibility of adhesion fault in the circuit, the microcontroller 3 sends a drive signal to the output short circuit detection and adhesion detection circuit 11 to control the fourth relay K4 in the output short circuit detection and adhesion detection circuit 11 to temporarily close, and continue to compare and analyze whether there is an output short circuit fault and in which circuit the fault occurs according to the stored code value-fault comparison table. If an output short circuit fault is detected, the microcontroller 3 will terminate the current charging process, send a fault signal, stop the operation of the charging pile to notify maintenance.

[0069] The specific embodiments described above further illustrate the technical problems, technical solutions and beneficial effects solved by the present invention. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A charging pile output fault detection circuit, used to be connected between a three-phase four-wire incoming line (2) and a charging output circuit (4), characterized in that: include: An output short circuit detection and adhesion detection circuit (11), the output short circuit detection and adhesion detection circuit (11) comprising four relays, four input terminals, four charging output terminals, four feedback signal output terminals and a driving terminal (1i), the input terminals being connected to the relays in a one-to-one correspondence, and the input terminals being respectively connected to each phase line and a neutral N line of a three-phase four-wire incoming line (2), the relay connected to the neutral N line being also connected to the driving terminal (1i), and the charging output terminal being connected to a charging output circuit (4); A microcontroller (3), wherein the signal input terminal of the microcontroller (3) is connected to the feedback signal output terminal, and the drive signal output terminal of the microcontroller (3) is connected to the drive terminal (1i); wherein, When the output short circuit detection and adhesion detection circuit (11) is powered on, the output short circuit detection and adhesion detection circuit (11) outputs corresponding feedback signals through four feedback signal output terminals according to the actual disconnection and closing conditions of each relay and transmits them to the microcontroller (3). The microcontroller (3) determines the adhesion conditions of each relay according to the received feedback signals and sends a drive signal to the drive terminal (1i) to control the relay connected to the neutral N line to close temporarily and continue to determine the output line short circuit conditions corresponding to each charging output terminal according to the received feedback signals during the short closing period.

2. The charging pile output fault detection circuit according to claim 1, characterized in that: After the microcontroller (3) determines that a relay has a sticking fault based on the received feedback signal, the microcontroller (3) terminates the current charging process, sends a fault signal, and stops the operation of the charging pile.

3. The charging pile output fault detection circuit according to claim 1, characterized in that: After the microcontroller (3) determines that a short circuit fault exists in the output line corresponding to the charging output terminal according to the received feedback signal, the microcontroller (3) terminates the current charging process, sends a fault signal, and stops the operation of the charging pile.

4. The charging pile output fault detection circuit according to claim 1, characterized in that: The feedback signal includes one of a low level, a high level and a PWM waveform, and four feedback signals constitute a state code.

5. The charging pile output fault detection circuit according to claim 1, characterized in that: The relays are respectively a first relay (K1), a second relay (K2), a third relay (K3) and a fourth relay (K4); the three-phase four-wire incoming line (2) comprises an A phase line, a B phase line, a C phase line and a neutral N line; the first relay (K1) is connected to the A phase line of the three-phase four-wire incoming line (2); the second relay (K2) is connected to the B phase line of the three-phase four-wire incoming line (2); the third relay (K3) is connected to the C phase line of the three-phase four-wire incoming line (2); and the fourth relay (K4) is connected to the neutral N line of the three-phase four-wire incoming line (2).

6. The charging pile output fault detection circuit according to claim 5, characterized in that: The output short circuit detection and adhesion detection circuit (11) further includes a first resistor (R1), a second resistor (R2), a third resistor (R3), a fourth resistor (R4), a fifth resistor (R5), a sixth resistor (R6), a first diode (D1), a second diode (D2), a third diode (D3), a fourth diode (D4), a fifth diode (D5), a sixth diode (D6), a first optical coupler (U1), a second optical coupler (U2), a third optical coupler (U3), a fourth optical coupler (U4), a fifth optical coupler (U5) and a sixth optical coupler (U6); wherein, The four input terminals are respectively a first input terminal (1a), a second input terminal (1b), a third input terminal (1c) and a fourth input terminal (1d); The four charging output terminals are respectively a first charging output terminal (1j), a second charging output terminal (1k), a third charging output terminal (1l) and a fourth charging output terminal (1m); The four feedback signal output terminals are respectively a first feedback signal output terminal (1e), a second feedback signal output terminal (1f), a third feedback signal output terminal (1g), and a fourth feedback signal output terminal (1h); The A phase line is connected to the first input terminal (1a), the first input terminal (1a) is connected to the 2nd pin of the first relay (K1) and the 1st pin of the first resistor (R1), the 2nd pin of the first resistor (R1) is connected to the negative electrode of the first diode (D1), the positive electrode of the first diode (D1) is connected to the K pin of the first optical coupler (U1), the A pin of the first optical coupler (U1) is connected to the 1st pin of the first relay (K1), the 1st pin of the fourth resistor (R4), and then connected to the first charging output terminal (1j); The B phase line is connected to the second input terminal (1b), the second input terminal (1b) is connected to the 2nd pin of the second relay (K2) and the 1st pin of the second resistor (R2), the 2nd pin of the second resistor (R2) is connected to the negative electrode of the second diode (D2), the positive electrode of the second diode (D2) is connected to the K pin of the second optical coupler (U2), the A pin of the second optical coupler (U2) is connected to the 1st pin of the second relay (K2), the 1st pin of the fifth resistor (R5), and then connected to the second charging output terminal (1k); The C phase line is connected to the third input terminal (1c), the third input terminal (1c) is connected to the 2nd pin of the third relay (K3) and the 1st pin of the third resistor (R3), the 2nd pin of the third resistor (R3) is connected to the negative electrode of the third diode (D3), the positive electrode of the third diode (D3) is connected to the K pin of the third optical coupler (U3), the A pin of the third optical coupler (U3) is connected to the 1st pin of the third relay (K3) and the 1st pin of the sixth resistor (R6), and then connected to the third charging output terminal (11); The neutral N line is connected to the fourth input terminal (1d), the fourth input terminal (1d) is connected to the 2nd pin of the fourth relay (K4), the 1st pin of the fourth relay (K4) is connected to the A pin of the sixth optical coupler (U6), the A pin of the fifth optical coupler (U5), the A pin of the fourth optical coupler (U4), the cathode of the sixth diode (D6), the cathode of the fifth diode (D5), the cathode of the fourth diode (D4), and then connected to the fourth charging output terminal (1m); The driving terminal (1i) is connected to the 6th pin of the fourth relay (K4); The C pin of the first optical coupler (U1) is connected to the C pin of the second optical coupler (U2), the C pin of the third optical coupler (U3), and then connected to the first charging output terminal (1e); Pin 2 of the fourth resistor (R4) is connected to the anode of the fourth diode (D4) and the pin K of the fourth optical coupler (U4); the pin C of the fourth optical coupler (U4) is connected to the second charging output terminal (1f); The 2nd pin of the fifth resistor (R5) is connected to the positive electrode of the fifth diode (D5) and the K pin of the fifth optical coupler (U5); the C pin of the fifth optical coupler (U5) is connected to the third charging output terminal (1g); The 2nd pin of the sixth resistor (R6) is connected to the positive electrode of the sixth diode (D6) and the K pin of the sixth optical coupler (U6); the C pin of the sixth optical coupler (U6) is connected to the fourth charging output terminal (1m); The E pin of the first optocoupler (U1) is connected to the E pin of the second optocoupler (U2), the E pin of the third optocoupler (U3), the E pin of the fourth optocoupler (U4), the E pin of the fifth optocoupler (U5), and the E pin of the sixth optocoupler (U6) as a reference ground.

7. A detection method for a charging pile output fault detection circuit according to any one of claims 1 to 6, characterized in that: The steps of the method include: When the output short circuit detection and adhesion detection circuit (11) is powered on, the output short circuit detection and adhesion detection circuit (11) outputs corresponding feedback signals through four feedback signal output terminals according to the actual disconnection and closing conditions of each relay and transmits them to the microcontroller (3). The microcontroller (3) determines the adhesion conditions of each relay according to the received feedback signals and sends a drive signal to the drive terminal (1i) to control the relay connected to the neutral N line to close temporarily and continue to determine the output line short circuit conditions corresponding to each charging output terminal according to the received feedback signals during the short closing period.

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