A method and device for detecting sticking of a general three-phase / single-phase alternating current charging pile output relay

Abstract

The application discloses a kind of general three-phase / single-phase alternating current charging pile output relay sticking detection method and device, method includes the following steps: provide a kind of general three-phase / single-phase alternating current charging pile output relay sticking detection device;After receiving charging instruction, keep output relay to be disconnected state, close switch circuit, utilize output processing circuit respectively to the contact output voltage of three-way output contact rectification after superposition, obtain first composite pulse waveform;First composite pulse waveform is handled by isolation circuit to obtain second composite pulse waveform, second transmission composite pulse waveform is to MCU, and MCU judges the sticking condition of output contact according to second composite pulse waveform;Implement the application, improve the detection accuracy of charging pile output relay, not only reduce cost, but also help more accurate, safe and reliable determination contact sticking condition.

Description

Technical Field

[0001] This invention relates to the field of relay adhesion detection technology for charging piles, and particularly to a method and device for detecting adhesion of output relays in general three-phase / single-phase AC charging piles. Background Technology

[0002] With the rapid development of electric vehicles, electric vehicle charging stations have also developed rapidly. Charging stations are a crucial infrastructure for electric vehicles, providing electrical energy for charging. AC charging stations, as a type of electric vehicle charging station, require their output side to be directly connected to the electric vehicle during operation. Therefore, the requirements for their safety and reliability are becoming increasingly stringent. The output-side relay plays a major electrical control role in AC charging stations. Due to the complex usage scenarios, it may be affected by various factors such as the charging gun or the electric vehicle's receiving device, leading to relay sticking and short-circuit faults. If a short circuit occurs on the output side of the charging station, it will not only damage the charging station itself but may also damage the electric vehicle's charging equipment.

[0003] To ensure charging safety, it is essential to perform safety testing on the output side of the charging gun. In the existing technology, there are two methods to test the output side relay: The first method is to test through the feedback signal of the output relay itself. However, when the output relay fails, the feedback signal is prone to abnormality, making it impossible to reliably detect the sticking of the output relay or accurately detect the specific sticking condition of the output relay. Summary of the Invention

[0004] In existing technologies, the adhesion detection technology for charging pile output relays has the problem of low accuracy, making it impossible to accurately determine the adhesion status of contacts.

[0005] To address the aforementioned problems, a universal method and device for detecting the adhesion of output relays in three-phase / single-phase AC charging piles is proposed. The method involves processing a first composite pulse waveform, then processing this waveform through an isolation circuit to obtain a second composite pulse waveform. An MCU is used to determine the adhesion status of the output contacts based on the second composite pulse waveform: one output contact is adhered, two output contacts are adhered, or all three output contacts are adhered. This improves the detection accuracy of the charging pile output relay, reduces costs, and facilitates more accurate, safe, and reliable determination of contact adhesion. Firstly, a universal method for detecting the adhesion of output relays in three-phase / single-phase AC charging piles includes: Step 100: Provide a universal three-phase / single-phase AC charging pile output relay adhesion detection device, including an output processing circuit, a switching circuit, an isolation circuit and an MCU. The output processing circuit is electrically connected to the three output contacts of the output relay, and the switching circuit is electrically connected to the output processing circuit and the isolation circuit respectively. Step 200: After receiving the charging command, keep the output relay in the open state, close the switching circuit, and use the output processing circuit to rectify and superimpose the contact output voltages of the three output contacts to obtain the first composite pulse waveform. Step 300: The first composite pulse waveform is processed by the isolation circuit to obtain a second composite pulse waveform. The second composite pulse waveform is transmitted to the MCU. The MCU determines the adhesion status of the output contact based on the second composite pulse waveform. The adhesion conditions include: One output contact is stuck together; The two output contacts are stuck together. All three output contacts are stuck together; The output processing circuit includes a first rectifier circuit, a second rectifier circuit, and a third rectifier circuit.

[0006] In conjunction with the adhesion detection method for the output relay of the universal three-phase / single-phase AC charging pile described in the first aspect of the present invention, in a first possible embodiment, step 200 includes: Step 210: Use the first rectifier circuit, the second rectifier circuit and the third rectifier circuit to rectify the output voltage of the first contact, the output voltage of the second contact and the output voltage of the third contact of the output relay respectively to obtain the first pulse waveform, the second pulse waveform and the third pulse waveform; Step 220: Superimpose the first pulse waveform, the second pulse waveform, and the third pulse waveform to obtain the first composite pulse waveform.

[0007] In conjunction with the first possible embodiment of the first aspect of the present invention, in the second possible embodiment, step 300 includes: Step 310: Drive the isolation circuit using the first composite pulse waveform; Step 320: The isolation circuit performs an inversion conversion on the first composite pulse waveform to obtain the second composite pulse waveform.

[0008] In conjunction with the second possible embodiment of the first aspect of the present invention, in the third possible embodiment, step 300 further includes: Step 330: Use the MCU to obtain the low-level pulse width and high-level pulse width of the second composite pulse waveform; Step 340: If the low-level pulse width is equal to the high-level pulse width, then the adhesion status is determined as follows: One output contact is stuck together.

[0009] In conjunction with the second possible implementation of the first aspect of the present invention, in the fourth possible implementation, step 300 further includes: Step 350: Use the MCU to obtain the low-level pulse width and high-level pulse width of the second composite pulse waveform; Step 360: If the low-level pulse width is twice the high-level pulse width, then the adhesion status is determined as follows: The two output contacts are stuck together.

[0010] In conjunction with the second possible implementation of the first aspect of the present invention, in the fifth possible implementation, step 300 further includes: Step 370: Use the MCU to obtain the low-level pulse width and high-level pulse width of the second composite pulse waveform; Step 380: If the high-level pulse width is zero and all signals are low-level signals, then the adhesion status is determined as follows: All three output contacts are stuck together.

[0011] Secondly, a universal three-phase / single-phase AC charging pile output relay adhesion detection device, employing the universal three-phase / single-phase AC charging pile output relay adhesion detection method described in the first aspect, includes: Output processing circuit; Switching circuit; Isolation circuit; MCU; The output processing circuit is electrically connected to the three output contacts of the output relay, the switching circuit is electrically connected to the output processing circuit and the isolation circuit respectively, and the isolation circuit is electrically connected to the MCU. The output processing circuit is used to rectify and superimpose the output voltages of the three output contacts to obtain the first composite pulse waveform. The switching circuit is used to control the opening / closing of the adhesion detection device according to control commands; The isolation circuit is used to process and convert the first composite pulse waveform to obtain a second composite pulse waveform, and transmit the second composite pulse waveform to the MCU; The MCU is used to determine the adhesion status of the output contacts based on the second composite pulse waveform; The adhesion conditions include: One output contact is stuck together; The two output contacts are stuck together. All three output contacts are stuck together.

[0012] In conjunction with the adhesion detection device for the universal three-phase / single-phase AC charging pile output relay described in the second aspect of the present invention, in a first possible embodiment, the output processing circuit includes: First rectifier circuit, second rectifier circuit, third rectifier circuit.

[0013] The first rectifier circuit, the second rectifier circuit, and the third rectifier circuit are respectively used to rectify the output voltage of the first contact, the output voltage of the second contact, and the output voltage of the third contact of the output relay to obtain the first pulse waveform, the second pulse waveform, and the third pulse waveform.

[0014] In conjunction with the first possible embodiment of the second aspect of the present invention, in the second possible embodiment, the isolation circuit includes: Current limiting circuit; Conversion circuit; The input terminal of the current limiting circuit is electrically connected to the output processing circuit, and the output terminal is electrically connected to the conversion circuit. The conversion circuit is used to process and convert the first composite pulse waveform to obtain the second composite pulse waveform.

[0015] In conjunction with the second possible implementation of the second aspect of the present invention, in the third possible implementation, after acquiring the low-level pulse width and high-level pulse width of the second composite pulse waveform, the MCU further determines: If the low-level pulse width is equal to the high-level pulse width, then the adhesion condition is determined as follows: One output contact is stuck together; If the low-level pulse width is twice the high-level pulse width, then the adhesion condition is determined as follows: The two output contacts are stuck together. If the high-level pulse width is zero and all signals are low-level signals, then the adhesion status is determined as follows: All three output contacts are stuck together.

[0016] The present invention provides a method and apparatus for detecting contact adhesion in a universal three-phase / single-phase AC charging pile output relay. By processing a first composite pulse waveform, and then processing the first composite pulse waveform through the isolation circuit to obtain a second composite pulse waveform, the MCU determines the adhesion status of the output contacts based on the second composite pulse waveform: one output contact is adhered, two output contacts are adhered, or all three output contacts are adhered. This improves the detection accuracy of the charging pile output relay, reduces costs, and helps to more accurately, safely, and reliably determine the contact adhesion status. (See attached figures.) To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of an embodiment of a method for detecting adhesion of a universal three-phase / single-phase AC charging pile output relay according to the present invention; Figure 2 for Figure 1 A schematic diagram of a specific embodiment of step 200; Figure 3 for Figure 1 A schematic diagram of a specific embodiment of step 300; Figure 4 for Figure 3 A schematic diagram of the first specific embodiment following step 320; Figure 5 for Figure 3 A schematic diagram of the second specific embodiment following step 320; Figure 6 for Figure 3 A schematic diagram of the third specific embodiment following step 320; Figure 7 For the corresponding Figure 4 A schematic diagram of the pulse waveform of the first specific embodiment; Figure 8 For the corresponding Figure 4 A schematic diagram of the pulse waveform of the second specific embodiment; Figure 9 For the corresponding Figure 4 A schematic diagram of the pulse waveform of the third specific embodiment; Figure 10 A schematic diagram of the pulse waveform in an embodiment where there is no adhesion; Figure 11 This is a schematic diagram of an embodiment of a universal three-phase / single-phase AC charging pile output relay adhesion detection device according to the present invention; Figure 12 for Figure 11 A schematic diagram of a circuit diagram of an embodiment of a universal three-phase / single-phase AC charging pile output relay adhesion detection device. Detailed Implementation

[0018] The technical solutions of this invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are all within the scope of protection of this invention.

[0019] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein in the specification of the application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings of this application are intended to cover non-exclusive inclusion.

[0021] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0022] In existing technologies, the adhesion detection technology for charging pile output relays has the problem of low accuracy, making it impossible to accurately determine the adhesion status of contacts.

[0023] To address the aforementioned issues, a general method and device for detecting adhesion of output relays in three-phase / single-phase AC charging piles is proposed.

[0024] Firstly, a method for detecting adhesion of the output relay in a general three-phase / single-phase AC charging pile, such as... Figure 1 , Figure 1 This is a schematic diagram of an embodiment of a method for detecting adhesion of a universal three-phase / single-phase AC charging pile output relay according to the present invention; including: Step 100: Provide a universal three-phase / single-phase AC charging pile output relay adhesion detection device, including an output processing circuit 101, a switching circuit 102, an isolation circuit 103 and an MCU 104. The output processing circuit 101 is electrically connected to the three output contacts of the output relay, and the switching circuit 102 is electrically connected to the output processing circuit 101 and the isolation circuit 103 respectively.

[0025] In this embodiment, before charging, the output contacts of the output relay are normally open. The MCU 104 controls the switching of the entire detection device through the control switch circuit 102, initiating the adhesion detection. The output processing circuit 101 processes the signal to obtain the first composite pulse waveform of the charging pile output relay. The isolation circuit 103 then inverts the first composite pulse waveform to obtain the second composite pulse waveform. The MCU 104 compares the high-level pulse width and low-level pulse width of the second composite pulse waveform to determine the specific adhesion situation. The adhesion situation of the output contacts can be one output contact adhesion, two output contacts adhesion, or all three output contacts adhesion, improving the detection accuracy of the charging pile output relay and thus helping to accurately determine the contact adhesion situation.

[0026] Step 200: After receiving the charging command, keep the output relay in the open state, close the switch circuit 102, and use the output processing circuit 101 to rectify and superimpose the contact output voltages of the three output contacts to obtain the first composite pulse waveform.

[0027] In one possible implementation, such as Figure 2 , Figure 2 for Figure 1 A schematic diagram of a specific embodiment of step 200; step 200 includes: Step 210: Rectify the first contact output voltage, second contact output voltage, and third contact output voltage of the output relay using the first rectifier circuit, the second rectifier circuit, and the third rectifier circuit respectively to obtain the first pulse waveform, the second pulse waveform, and the third pulse waveform; Step 220: Superimpose the first pulse waveform, the second pulse waveform, and the third pulse waveform to obtain the first composite pulse waveform.

[0028] In this embodiment, when adhesion occurs, the AC voltage output by the output contacts needs to be rectified by the first rectifier circuit, the second rectifier circuit, and the third rectifier circuit to obtain the first pulse waveform, the second pulse waveform, and the third pulse waveform, respectively. These waveforms are then superimposed by the circuit to obtain the first composite pulse waveform. The low-level pulse width and the high-level pulse width are different for different adhesion conditions.

[0029] Step 300: The first composite pulse waveform is processed by the isolation circuit 103 to obtain the second composite pulse waveform. The second composite pulse waveform is transmitted to the MCU 104. The MCU 104 determines the adhesion status of the output contacts based on the second composite pulse waveform.

[0030] In one possible implementation, such as Figure 3 , Figure 3 for Figure 1A schematic diagram of a specific embodiment of step 300; step 300 includes: step 310, using the first composite pulse waveform to drive the isolation circuit 103; step 320, the isolation circuit 103 performs an inversion conversion on the first composite pulse waveform to obtain a second composite pulse waveform.

[0031] In this embodiment, the isolation circuit 103 inverts the first composite pulse waveform by sampling and conversion, that is, the high-level pulse width and low-level pulse width of the converted waveform are opposite to the high-level pulse width and low-level pulse width of the first composite pulse waveform.

[0032] In one possible implementation, such as Figure 4 , Figure 4 for Figure 3 The first specific embodiment diagram after step 320; step 300 also includes: step 330, using MCU104 to obtain the low-level pulse width and high-level pulse width of the second composite pulse waveform; step 340, if the low-level pulse width and the high-level pulse width are equal, then the adhesion situation is determined to be that one output contact is stuck.

[0033] In this embodiment, as Figure 7 , Figure 7 For the corresponding Figure 4 The first specific embodiment of the diagram shows a pulse waveform. After rectifying, superimposing, and inverting the AC voltage, the equal widths of the high-level pulse and the low-level pulse indicate that one of the output contacts is stuck.

[0034] In one possible implementation, such as Figure 5 , Figure 5 for Figure 3 The second specific embodiment diagram after step 320; step 300 also includes: step 350, using MCU104 to obtain the low-level pulse width and high-level pulse width of the second composite pulse waveform; step 360, if the low-level pulse width is twice the high-level pulse width, then the adhesion situation is determined to be adhesion of the two output contacts.

[0035] In this embodiment, as Figure 8 , Figure 8 For the corresponding Figure 4 The second specific embodiment of the pulse waveform diagram; after rectifying, superimposing and inverting the AC voltage, the low-level pulse width is equal to twice the high-level pulse width, which indicates that the two output contacts are stuck together.

[0036] In one possible implementation, such as Figure 6 , Figure 6 for Figure 3The schematic diagram of the third specific embodiment after step 320; step 300 also includes: step 370, using MCU104 to obtain the low-level pulse width and high-level pulse width of the second composite pulse waveform; step 380, if the high-level pulse width is zero, all are low-level signals, then it is determined that the adhesion situation is that all three output contacts are adhered.

[0037] In this embodiment, as Figure 9 , Figure 9 For the corresponding Figure 4 The pulse waveform diagram of the third specific embodiment is shown below. After rectifying, superimposing, and inverting the AC voltage, all pulse widths are low, indicating that the two output contacts are stuck together. The case without sticking is as follows... Figure 10 , Figure 10 The following is a schematic diagram of the pulse waveform in the case of no adhesion; all are high-level pulse widths.

[0038] In this embodiment, a first composite pulse waveform is obtained through processing, and the first composite pulse waveform is processed by isolation circuit 103 to obtain a second composite pulse waveform. MCU 104 uses the second composite pulse waveform to determine the adhesion status of the output contacts: one output contact is adhered, two output contacts are adhered, or all three output contacts are adhered. This improves the detection accuracy of the charging pile output relay, thereby helping to accurately determine the adhesion status of the contacts.

[0039] Secondly, a universal three-phase / single-phase AC charging pile output relay adhesion detection device, such as... Figure 11 , Figure 11 This is a schematic diagram of an embodiment of a universal three-phase / single-phase AC charging pile output relay adhesion detection device according to the present invention; the universal three-phase / single-phase AC charging pile output relay adhesion detection method of the first aspect includes an output processing circuit 101, a switching circuit 102, an isolation circuit 103, and an MCU 104; the output processing circuit 101 is electrically connected to the three output contacts of the output relay, the switching circuit 102 is electrically connected to the output processing circuit 101 and the isolation circuit 103 respectively, and the isolation circuit 103 is electrically connected to the MCU 104; the output processing circuit 101... 01 is used to rectify and superimpose the output voltages of the three output contacts to obtain a first composite pulse waveform; the switching circuit 102 is used to control the opening / closing of the adhesion detection device according to the control command; the isolation circuit 103 is used to process and convert the first composite pulse waveform to obtain a second composite pulse waveform, and transmit the second composite pulse waveform to the MCU 104; the MCU 104 is used to determine the adhesion status of the output contacts according to the second composite pulse waveform; wherein, the adhesion status includes one output contact adhesion, two output contacts adhesion, and all three output contacts adhesion.

[0040] In one possible implementation, the output processing circuit 101 includes a first rectifier circuit, a second rectifier circuit, and a third rectifier circuit. The first rectifier circuit, the second rectifier circuit, and the third rectifier circuit are respectively used to rectify the output voltage of the first contact, the output voltage of the second contact, and the output voltage of the third contact of the output relay to obtain a first pulse waveform, a second pulse waveform, and a third pulse waveform.

[0041] In one possible implementation, the isolation circuit 103 includes a current limiting circuit and a conversion circuit; the input terminal of the current limiting circuit is electrically connected to the output processing circuit 101, and the output terminal is electrically connected to the conversion circuit; the conversion circuit is used to process and convert the first composite pulse waveform to obtain a second composite pulse waveform.

[0042] In one possible implementation, after acquiring the low-level pulse width and high-level pulse width of the second composite pulse waveform, the MCU104 further uses them to determine: If the low-level pulse width is equal to the high-level pulse width, the sticking situation is determined to be one output contact sticking. If the low-level pulse width is twice the high-level pulse width, the sticking situation is determined to be two output contacts sticking. If the high-level pulse width is zero, all are low-level signals, the sticking situation is determined to be all three output contacts sticking.

[0043] In this embodiment, the circuit diagram of the adhesion detection device is as follows: Figure 12 , Figure 12 for Figure 11 A schematic diagram of a circuit diagram for an embodiment of a universal three-phase / single-phase AC charging pile output relay adhesion detection device. The output processing circuit 101 includes a first rectifier circuit, a second rectifier circuit, and a third rectifier circuit, each including diode D1, diode D2, and diode D3 respectively. The isolation circuit 103 includes a resistor R1, an optocoupler U1, a diode D4, and a resistor R2. The switching circuit 102 includes a resistor R3, a transistor Q1, a diode D5, and a relay K1. The circuit connections are as follows: The anodes of diodes D1, D2, and D3 are electrically connected to the three output contacts L10, L20, and L30 of a general-purpose three-phase / single-phase AC charging pile output relay, respectively. The cathodes of diodes D1, D2, and D3 are connected together and then electrically connected to one end of resistor R1. Pin 1 of the optocoupler U1 is electrically connected to the other end of resistor R1 and to the cathode of diode D4. Pin 2 of the optocoupler U1 and the anode of diode D4 are electrically connected to pin 5 of relay K1. Pin 4 of the optocoupler U1 is connected together with one end of resistor R2 and then connected to the MCU104. The sample port AD-Adhesion is electrically connected; the other end of R2 is electrically connected to the 3.3V power supply; pin 3 of the optocoupler U1 output is electrically connected to GND; pin 3 of the relay K1 is electrically connected to the input contact N of the universal three-phase / single-phase AC charging pile output relay; one end of the resistor R3 is electrically connected to the MCU104 control port Relay-Adhesion; the base of the transistor Q1 is electrically connected to the other end of the resistor R3; the drain of the transistor Q1 and the anode of the diode D5 are electrically connected to pin 2 of the relay K1; the cathode of the diode D5 and pin 1 of the relay are electrically connected to the 12V power supply.

[0044] In the circuit, relay K1 is normally open. Before the circuit starts working, relay K1 is controlled to switch on and off to detect the voltage when the relays in the three-phase circuit stick together. This voltage is then sent to MCU104. MCU104 then controls whether the overall charging circuit continues to work. When the Relay-Adhesion signal is high, relay K1 is closed, and the detection function is started; when the Relay-Adhesion signal is low, relay K1 is open, and the detection function stops.

[0045] When the charging pile is connected to power and starts charging, the output relay of the charging pile is in the open state. At this time, the MCU104 will first check whether the main circuit of the charging pile and each control and protection loop are normal. After the detection is normal, it will issue a command to close the output relay before the charging work starts.

[0046] It is worth noting that, Figure 12 The circuit schematic is only Figure 11 This is a specific embodiment used to illustrate the principle and is not intended to limit the scope of protection of this application.

[0047] The present invention provides a method and apparatus for detecting contact adhesion in a general three-phase / single-phase AC charging pile output relay. A first composite pulse waveform is obtained through processing. This first composite pulse waveform is then processed by an isolation circuit 103 to obtain a second composite pulse waveform. An MCU 104 determines the contact adhesion status of the output contacts based on the second composite pulse waveform: one output contact is adhered, two output contacts are adhered, or all three output contacts are adhered. This improves the detection accuracy of the charging pile output relay, reduces costs, and helps to more accurately, safely, and reliably determine the contact adhesion status. The above is only a preferred embodiment of the present invention and is not intended to limit the invention. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for detecting adhesion of a universal three-phase / single-phase AC charging pile output relay, characterized in that it includes: Step 100: Provide a universal three-phase / single-phase AC charging pile output relay adhesion detection device, including an output processing circuit, a switching circuit, an isolation circuit and an MCU. The output processing circuit is electrically connected to the three output contacts of the output relay, and the switching circuit is electrically connected to the output processing circuit and the isolation circuit respectively. Step 200: After receiving the charging command, keep the output relay in the open state, close the switching circuit, and use the output processing circuit to rectify and superimpose the contact output voltages of the three output contacts to obtain the first composite pulse waveform. Step 300: The first composite pulse waveform is processed by the isolation circuit to obtain a second composite pulse waveform. The second composite pulse waveform is transmitted to the MCU. The MCU determines the adhesion status of the output contact based on the second composite pulse waveform. The adhesion conditions include: One output contact is stuck together; The two output contacts are stuck together. All three output contacts are stuck together; The output processing circuit includes a first rectifier circuit, a second rectifier circuit, and a third rectifier circuit.

2. The method for detecting adhesion of the universal three-phase / single-phase AC charging pile output relay according to claim 1, characterized in that, Step 200 includes: Step 210: Use the first rectifier circuit, the second rectifier circuit, and the third rectifier circuit to rectify the output voltage of the first contact, the output voltage of the second contact, and the output voltage of the third contact of the output relay, respectively, to obtain the first pulse waveform, the second pulse waveform, and the third pulse waveform. Step 220: Superimpose the first pulse waveform, the second pulse waveform, and the third pulse waveform to obtain the first composite pulse waveform.

3. The adhesion detection method for the output relay of a universal three-phase / single-phase AC charging pile according to claim 2, characterized in that, Step 300 includes: Step 310: Drive the isolation circuit using the first composite pulse waveform; Step 320: The isolation circuit performs an inversion conversion on the first composite pulse waveform to obtain the second composite pulse waveform.

4. The adhesion detection method for the output relay of a universal three-phase / single-phase AC charging pile according to claim 3, characterized in that, Step 300 further includes: Step 330: Use the MCU to obtain the low-level pulse width and high-level pulse width of the second composite pulse waveform; Step 340: If the low-level pulse width is equal to the high-level pulse width, then the adhesion status is determined as follows: One output contact is stuck together.

5. The method for detecting adhesion of the universal three-phase / single-phase AC charging pile output relay according to claim 3, characterized in that, Step 300 further includes: Step 350: Use the MCU to obtain the low-level pulse width and high-level pulse width of the second composite pulse waveform; Step 360: If the low-level pulse width is twice the high-level pulse width, then the adhesion status is determined as follows: The two output contacts are stuck together.

6. The adhesion detection method for the output relay of a universal three-phase / single-phase AC charging pile according to claim 3, characterized in that, Step 300 further includes: Step 370: Use the MCU to obtain the low-level pulse width and high-level pulse width of the second composite pulse waveform; Step 380: If the high-level pulse width is zero and all signals are low-level signals, then the adhesion status is determined as follows: All three output contacts are stuck together.

7. A universal three-phase / single-phase AC charging pile output relay adhesion detection device, employing the universal three-phase / single-phase AC charging pile output relay adhesion detection method according to any one of claims 1-6, characterized in that, include: Output processing circuit; Switching circuit; Isolation circuit; MCU; The output processing circuit is electrically connected to the three output contacts of the output relay, the switching circuit is electrically connected to the output processing circuit and the isolation circuit respectively, and the isolation circuit is electrically connected to the MCU. The output processing circuit is used to rectify and superimpose the output voltages of the three output contacts to obtain the first composite pulse waveform. The switching circuit is used to control the opening / closing of the adhesion detection device according to control commands; The isolation circuit is used to process and convert the first composite pulse waveform to obtain a second composite pulse waveform, and transmit the second composite pulse waveform to the MCU; The MCU is used to determine the adhesion status of the output contacts based on the second composite pulse waveform; The adhesion conditions include: One output contact is stuck together; The two output contacts are stuck together. All three output contacts are stuck together.

8. The adhesion detection device for the output relay of a universal three-phase / single-phase AC charging pile according to claim 7, characterized in that, The output processing circuit includes: First rectifier circuit, second rectifier circuit, third rectifier circuit; The first rectifier circuit, the second rectifier circuit, and the third rectifier circuit are respectively used to rectify the output voltage of the first contact, the output voltage of the second contact, and the output voltage of the third contact of the output relay to obtain the first pulse waveform, the second pulse waveform, and the third pulse waveform.

9. The adhesion detection device for the output relay of a universal three-phase / single-phase AC charging pile according to claim 8, characterized in that, The isolation circuit includes: Current limiting circuit; Conversion circuit; The input terminal of the current limiting circuit is electrically connected to the output processing circuit, and the output terminal is electrically connected to the conversion circuit. The conversion circuit is used to process and convert the first composite pulse waveform to obtain the second composite pulse waveform.

10. The adhesion detection device for the output relay of a universal three-phase / single-phase AC charging pile according to claim 9, characterized in that, After acquiring the low-level pulse width and high-level pulse width of the second composite pulse waveform, the MCU further uses them to determine: If the low-level pulse width is equal to the high-level pulse width, then the adhesion condition is determined as follows: One output contact is stuck together; If the low-level pulse width is twice the high-level pulse width, then the adhesion condition is determined as follows: The two output contacts are stuck together. If the high-level pulse width is zero and all signals are low-level signals, then the adhesion status is determined as follows: All three output contacts are stuck together.

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