CN-121978516-A - Method for detecting adhesion and tripping of charging circuit

CN121978516ACN 121978516 ACN121978516 ACN 121978516ACN-121978516-A

Abstract

The invention relates to a detection method for blocking and tripping of a charging circuit, which comprises the following steps of S1, collecting voltages V1 and V2 on the load side of a relay, S2, determining the control state of the relay, executing step S3 if the control state of the relay is open, executing step S4 if the control state of the relay is closed, S3, calculating the voltage difference between V1 and V2, executing step S5 if the absolute value of the voltage difference is larger than a first set voltage and V1 or V2 is larger than a second set voltage, otherwise executing step S1, S4, calculating the voltage difference between V1 and V2, executing step S6 if the absolute value of the voltage difference is smaller than the first set voltage and V1 and V2 is smaller than a third set voltage, otherwise executing step S1, S5, outputting a blocking alarm of the relay, executing step S1, S6, outputting a tripping alarm of the relay and executing step S1. The invention can reliably detect whether the relay is stuck or tripped.

Inventors

Wu Ronghuai
Yan Shanmao
ZHANG XUEGONG

Assignees

著赫(厦门)新能源技术有限公司

Dates

Publication Date: 20260505
Application Date: 20260109

Claims (10)

1. The detection method for the adhesion tripping of the charging circuit is characterized by comprising the following steps of: S1, collecting voltages V1 and V2 at the load side of a relay, wherein the voltages of a live wire at the load side of the relay and the voltage of a zero wire are respectively V1 and V2 for a charging circuit with single-phase power supply, the voltages of two live wires at the load side of the relay are respectively V1 and V2 for a charging circuit with double-phase power supply, and the voltages of the zero wire at the load side of the relay and any live wire are respectively V1 and V2 for a charging circuit with three-phase power supply; s2, determining a control state of the relay, if the control state of the relay is open, executing a step S3, and if the control state of the relay is closed, executing a step S4; S3, taking V1 and V2 collected at the same moment or V1 collected at any moment and V2 collected in adjacent collection periods, then calculating the voltage difference between the V1 and the V2, and executing the step S5 if the absolute value of the voltage difference is larger than a first set voltage and V1 or V2 is larger than a second set voltage, otherwise executing the step S1; S4, taking V1 and V2 collected at the same moment or V1 collected at any moment and V2 collected in adjacent collection periods, then calculating the voltage difference between the V1 and the V2, and executing a step S6 if the absolute value of the voltage difference is smaller than a first set voltage and the V1 and the V2 are smaller than a third set voltage, otherwise executing the step S1; s5, outputting a relay adhesion alarm, and then executing the step S1; s6, outputting a relay trip alarm, and then executing the step S1; When the relay is disconnected, the first set voltage is obtained by adding an error value to the product of the maximum virtual voltage at the load side of the relay and a coefficient value, wherein the coefficient value is a sine value obtained by subtracting the product of the voltage acquisition period and the power supply frequency from 1.
2. The method for detecting adhesion and trip of a charging circuit according to claim 1, wherein in step S3, when the second set voltage is compared with V1 or V2, the values of V1 and V2 are the maximum values of V1 and V2 in the set period, respectively, and in step S4, when the third set voltage is compared with V1 or V2, the values of V1 and V2 are the maximum values of V1 and V2 in the set period, respectively, and the set period is not smaller than the voltage period of the power supply.
3. The method for detecting adhesion and trip of a charging circuit according to claim 2, wherein the set period is at least 1.5 times the voltage period of the power supply.
4. The method for detecting adhesion and tripping of a charging circuit according to claim 1, wherein in step S5, a fault count is first performed, if the fault count exceeds a first set number, a relay adhesion alarm is output, then step S1 is executed, otherwise step S1 is directly executed, and in step S6, if the fault count exceeds a second set number, a relay trip alarm is output, then step S1 is executed, otherwise step S1 is directly executed.
5. The method according to claim 4, wherein in step S3, if it is determined that the step S1 is performed in a skip mode, before the step S1 is performed, it is determined whether the failure count exceeds a first set number of times, if yes, the failure count in step S5 is cleared, then the step S1 is performed, otherwise, the step S1 is directly performed, and in step S4, if it is determined that the step S1 is performed in a skip mode, before the step S1 is performed, it is determined whether the failure count exceeds a second set number of times, if yes, the failure count in step S5 is cleared, then the step S1 is performed, and otherwise, the step S1 is directly performed.
6. The method for detecting adhesion and trip of a charging circuit according to claim 4, further comprising a step SA, which is executed after the step S1 and before the step S2, for judging whether the control state of the relay is changed, if the control state of the relay is changed, clearing the fault counts in the step S5 and the step S6, and then executing the step S2, otherwise, directly executing the step S2.
7. The method for detecting adhesion and trip of a charging circuit according to claim 1, wherein the second set voltage is equal to a third set voltage, and the second set voltage is not lower than the first set voltage.
8. The method for detecting adhesion and tripping of a charging circuit according to claim 1, wherein the voltage acquisition period is not more than 200 microseconds.
9. The method for detecting adhesion and tripping of a charging circuit according to claim 1, wherein the power supply is commercial power.
10. The method for detecting adhesion tripping of a charging circuit according to claim 1, wherein voltages V1 and V2 on a load side of the relay are collected through a collecting circuit, the collecting circuit comprises a controller, a V1 collecting circuit and a V2 collecting circuit, the V1 collecting circuit and the V2 collecting circuit comprise a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a filter capacitor and a bidirectional voltage regulator tube, one end of the first resistor is connected with a power line corresponding to the load side of the relay, the other end of the second resistor is connected with one end of the fourth resistor through the second resistor and the third resistor, the other end of the fourth resistor is connected with one end of the filter capacitor, a corresponding collecting pin on the controller, one end of the fifth resistor and 3 pins of the bidirectional voltage regulator tube, the other end of the filter capacitor, the other end of the fifth resistor and 1 pin of the bidirectional voltage regulator tube are grounded, and the 2 pins of the bidirectional voltage regulator tube are connected with a power input end of the controller.

Description

Method for detecting adhesion and tripping of charging circuit Technical Field The invention relates to the technical field of charging guns, in particular to a method for detecting adhesion and tripping of a charging circuit. Background In an ac charging system, a relay is usually provided inside the charging gun for physically disconnecting the high-voltage circuit between the grid and the vehicle in the non-charged state, to ensure the safety of the user operation. Because the relay can be adhered or tripped, the charging gun is usually provided with a corresponding detection circuit for detection, so that the use safety is ensured. However, in practical application, especially when the charging gun is connected to an unreliable-grounded aging test load box, an electric leakage tester and other instruments, a special interference phenomenon often occurs, namely, even if the relay is completely disconnected and charging is not started, the output end of the charging gun can still detect an induced voltage of tens of volts or even hundreds of volts (commonly called as virtual electricity). The virtual electricity mainly originates from parasitic capacitive coupling between a high-voltage cable at the power grid side and a floating metal structure, and is represented as a 50Hz power frequency alternating current signal, and although the virtual electricity has no actual driving capability, the virtual electricity is enough to be mistakenly recognized as 'loop conduction' by a voltage sampling circuit in a charging gun control system. Although some schemes attempt to suppress interference by adding a filter circuit or increasing a voltage threshold, such methods have difficulty in combining sensitivity and immunity, for example, an optocoupler is high in cost, and if only virtual power supplies enough current to light an LED, the optocoupler is turned on and misjudges as adhesion. Therefore, a more reliable adhesion detection method is needed, which can accurately distinguish whether the relay is actually conducted or is in virtual electricity induction, so that erroneous judgment caused by virtual electricity is effectively avoided on the premise of ensuring safety, and system robustness and user experience are improved. Disclosure of Invention The invention aims to provide a detection method for adhesion tripping of a charging circuit, which can reliably detect the adhesion tripping state of an alternating current charging circuit and avoid misjudgment caused by virtual conductance. In order to achieve the above purpose, the invention adopts the following technical scheme: a detection method for adhesion tripping of a charging circuit comprises the following steps: S1, collecting voltages V1 and V2 at the load side of a relay, wherein the voltages of a live wire at the load side of the relay and the voltage of a zero wire are respectively V1 and V2 for a charging circuit with single-phase power supply, the voltages of two live wires at the load side of the relay are respectively V1 and V2 for a charging circuit with double-phase power supply, and the voltages of the zero wire at the load side of the relay and any live wire are respectively V1 and V2 for a charging circuit with three-phase power supply; s2, determining a control state of the relay, if the control state of the relay is open, executing a step S3, and if the control state of the relay is closed, executing a step S4; S3, taking V1 and V2 collected at the same moment or V1 collected at any moment and V2 collected in adjacent collection periods, then calculating the voltage difference between the V1 and the V2, and executing the step S5 if the absolute value of the voltage difference is larger than a first set voltage and V1 or V2 is larger than a second set voltage, otherwise executing the step S1; S4, taking V1 and V2 collected at the same moment or V1 collected at any moment and V2 collected in adjacent collection periods, then calculating the voltage difference between the V1 and the V2, and executing a step S6 if the absolute value of the voltage difference is smaller than a first set voltage and the V1 and the V2 are smaller than a third set voltage, otherwise executing the step S1; s5, outputting a relay adhesion alarm, and then executing the step S1; s6, outputting a relay trip alarm, and then executing the step S1; When the relay is disconnected, the first set voltage is obtained by adding an error value to the product of the maximum virtual voltage at the load side of the relay and a coefficient value, wherein the coefficient value is a sine value obtained by subtracting the product of the voltage acquisition period and the power supply frequency from 1. Preferably, in step S3, the values of V1 and V2 are the maximum values of V1 and V2 in the set period when the second set voltage is compared with V1 or V2, respectively, and in step S4, the values of V1 and V2 are the maximum values of V1 and V2 in the set period when the third set vol