CN-121091150-B - Broken wire detection circuit, broken wire detection method and charging system

CN121091150BCN 121091150 BCN121091150 BCN 121091150BCN-121091150-B

Abstract

The application provides a broken wire detection circuit, a broken wire detection method and a charging system. The broken line detection circuit is applied to electric equipment and comprises a power supply loop, a first detection branch, a biasing circuit and a control circuit, wherein the power supply loop is used for providing power for a first resistor in a charging device, the first detection branch is connected between a first detection point and a first sampling port of the control circuit and used for detecting first voltage at the first detection point, the biasing circuit is arranged on the first detection branch and used for biasing the first voltage at the first detection point and providing bias voltage for the first sampling port of the control circuit, and the control circuit is used for controlling the power supply loop to be in a disconnected state when the electric equipment is charged through the charging device and detecting broken line between a ground wire of the electric equipment and a ground wire of the charging device according to the bias voltage. The application can realize the detection of the broken wire between the ground wire of the electric equipment and the ground wire of the charging device.

Inventors

WANG XINGCHANG
YE FUMING
KONG TINGTING
CHEN WEIJIE

Assignees

宁德时代润智软件科技有限公司
宁德时代新能源科技股份有限公司

Dates

Publication Date: 20260512
Application Date: 20251112

Claims (15)

1. The utility model provides a broken string detection circuitry, its characterized in that is applied to the consumer, broken string detection circuitry includes power supply loop, first detection branch road, biasing circuit and control circuit, wherein: The power supply loop is used for providing power for a first resistor in the charging device; The first detection branch is connected between a first detection point and a first sampling port of the control circuit and is used for detecting a first voltage at the first detection point, wherein the power supply loop comprises a disconnection detection switch and a first power supply, the first power supply and the disconnection detection switch are connected in series, and the first detection point is arranged between the disconnection detection switch and the first resistor; The bias circuit is arranged on the first detection branch and is used for biasing the first voltage at the first detection point and providing bias voltage for a first sampling port of the control circuit; And the control circuit is used for controlling the power supply loop to be in a disconnection state when the electric equipment is charged through the charging device, and detecting disconnection between the ground wire of the electric equipment and the ground wire of the charging device according to the bias voltage obtained by the first sampling port.
2. The wire breakage detection circuit according to claim 1, wherein, The control circuit is also used for determining that no disconnection fault exists between the ground wire of the electric equipment and the ground wire of the charging device when the amplitude of the bias voltage is in a first preset range, and determining that the disconnection fault exists between the ground wire of the electric equipment and the ground wire of the charging device when the amplitude of the bias voltage is in a second preset range; Wherein the lower limit value of the first preset range is higher than the upper limit value of the second preset range.
3. The disconnection detection circuit according to claim 1, wherein the control circuit is further configured to control the disconnection detection switch to be opened to place the power supply circuit in an open state when the electric consumer is charged by the charging device.
4. The wire break detection circuit of claim 3, wherein the bias circuit comprises a first bias branch and a second bias branch, wherein: the second bias branch is arranged on the first detection branch; The first bias branch is connected between the power supply loop and the first bias branch in a bridging way.
5. The wire break detection circuit of claim 4, wherein the first bias branch comprises a first bias resistor and the second bias branch comprises a second bias resistor, wherein: The first end of the first bias resistor is connected with the positive electrode of the first power supply; The first end of the second bias resistor is connected with the first detection point; And the second end of the first bias resistor is respectively connected with the second end of the second bias resistor and the first sampling port.
6. The wire break detection circuit of claim 1, further comprising a first filter circuit disposed between the bias circuit and the first sampling port, wherein: the first filter circuit is used for performing voltage stabilization filtering on the bias voltage so that the first sampling port obtains the bias voltage meeting a first condition.
7. The wire break detection circuit of claim 3, wherein the power supply loop further comprises a first pull-up resistor, wherein: the first pull-up resistor is connected in series with a connecting wire between the first power supply and the disconnection detection switch.
8. The wire breakage detection circuit according to any one of claims 1 to 7, further comprising a second detection branch, wherein: The second detection branch is connected between the first detection point and a second sampling port of the control circuit and is used for detecting a first voltage at the first detection point; And the control circuit is used for controlling the power supply loop to be in a disconnection state when the electric equipment is charged through the charging device, and detecting disconnection between the ground wire of the electric equipment and the ground wire of the charging device according to the first voltage obtained by the second sampling port and the bias voltage obtained by the first sampling port.
9. The wire breakage detection circuit according to claim 8, wherein, The control circuit is further configured to determine that a disconnection fault does not exist between the ground wire of the electric device and the ground wire of the charging device when the amplitude of the first voltage is in a third preset range and the amplitude of the bias voltage is out of a second preset range, and determine that a disconnection fault exists between the ground wire of the electric device and the ground wire of the charging device when the amplitude of the bias voltage is in the second preset range and the amplitude of the first voltage is out of the third preset range.
10. The wire break detection circuit of claim 8, further comprising a second filter circuit disposed on the second detection branch, wherein: The second filter circuit is configured to perform voltage stabilizing filtering on the first voltage at the first detection point, so that the second sampling port obtains a first voltage that meets a second condition.
11. The broken line detection method is characterized by being applied to a broken line detection circuit in electric equipment, the broken line detection circuit comprises a power supply loop, a first detection branch, a bias circuit and a control circuit, the power supply loop is used for providing power for a first resistor in a charging device, the first detection branch is connected between a first detection point and a first sampling port of the control circuit, the power supply loop comprises a broken line detection switch and a first power supply, the first power supply is connected with the broken line detection switch in series, the first detection point is arranged between the broken line detection switch and the first resistor, the bias circuit is arranged on the first detection branch, and the broken line detection method comprises the following steps of, in the case that the electric equipment is charged through the charging device: The control circuit controls the power supply loop to be in an off state, and obtains bias voltage provided by the bias circuit through the first sampling port; and detecting disconnection between the ground wire of the electric equipment and the ground wire of the charging device based on the bias voltage.
12. The wire breakage detection method as claimed in claim 11, wherein in case the wire breakage detection circuit further includes a second detection branch connected between the first detection point and a second sampling port of the control circuit, the wire breakage detection method further includes: The control circuit controls the power supply loop to be in an off state, and obtains a first voltage at the first detection point through the second sampling port; And detecting disconnection between the ground wire of the electric equipment and the ground wire of the charging device based on the bias voltage and the first voltage.
13. The wire breakage detection method according to claim 12, wherein in a case where the wire breakage detection circuit further includes a third detection branch connected between a second detection point and a third sampling port of the control circuit, the wire breakage detection method further includes: the control circuit controls the power supply loop to be in a disconnected state, and obtains a first sampling signal through the second sampling port and a third sampling signal through the third sampling port; The control circuit controls the power supply loop to be in a communication state, and obtains a second sampling signal through the second sampling port and a fourth sampling signal through the third sampling port; and detecting disconnection between the ground wire of the electric equipment and the ground wire of the charging device based on the first sampling signal, the third sampling signal, the second sampling signal and the fourth sampling signal.
14. The method for detecting disconnection according to claim 13, wherein the detecting disconnection between the ground of the electric device and the ground of the charging device based on the first sampling signal, the third sampling signal, the second sampling signal, and the fourth sampling signal includes: Determining that a disconnection fault exists between the ground wire of the electric equipment and the ground wire of the charging device under the condition that the first sampling signal, the third sampling signal, the second sampling signal and the fourth sampling signal are all in a first level state; And under the condition that the first sampling signal, the third sampling signal and the fourth sampling signal are in the first level state and the second sampling signal is in the second level state, determining that a charging switch between the electric equipment and the charging device is disconnected.
15. A charging system, comprising a charging device and an electrical consumer, wherein the electrical consumer is coupled to the charging device and the electrical consumer comprises a disconnection detection circuit according to any of claims 1-10.

Description

Broken wire detection circuit, broken wire detection method and charging system Technical Field The application relates to the technical field of batteries, in particular to a broken wire detection circuit, a broken wire detection method and a charging system. Background In an electric automobile direct current charging system, in order to ensure electrical safety in a charging process, a national standard has set clear requirements for circuit breaking detection of Protective Earth (PE) wires of electric equipment (for example, vehicles). The detection is intended to confirm whether the ground connection between the vehicle and the charging device (e.g., charging gun) is normal during charging, to prevent potential safety hazards due to breakage of the ground. In the related art, the voltage signal of the second connection confirmation terminal (2nd Charging Connection,CC2) is directly supplied to the micro control unit (Microcontroller Unit, MCU) for sampling after being subjected to RC filtering, and in the scheme, under the normal charging application condition, the voltage signal at the second connection confirmation terminal CC2 can be acquired, but when the PE line is broken, the voltage signal at the second connection confirmation terminal CC2 cannot be acquired, and the sampling signal is lost in the PE broken state, so that the scheme cannot realize detection on whether the broken PE line occurs. Disclosure of Invention The embodiment of the application provides a broken wire detection circuit, a broken wire detection method and a charging system, which can realize the detection of broken wires of PE wires. The technical scheme of the embodiment of the application is realized as follows: In a first aspect, an embodiment of the present application provides a disconnection detecting circuit, which is applied to electric equipment, where the disconnection detecting circuit includes a power supply loop, a first detecting branch, a bias circuit and a control circuit, where the power supply loop is used to provide power for a first resistor in a charging device; the first detection branch is connected between the first detection point and a first sampling port of the control circuit and used for detecting first voltage at the first detection point, the bias circuit is arranged on the first detection branch and used for biasing the first voltage at the first detection point and providing bias voltage for the first sampling port of the control circuit, and the control circuit is used for controlling the power supply loop to be in a disconnection state when the electric equipment is charged through the charging device and detecting disconnection between the ground wire of the electric equipment and the ground wire of the charging device according to the bias voltage obtained by the first sampling port. According to the technical means, the power supply circuit is used for supplying power to the first resistor in the charging device, the first voltage of the first detection point is collected through the first detection branch circuit, the first voltage is subjected to bias processing through the bias circuit, so that a possible negative pressure signal is converted into a positive pressure signal and is input to the control circuit, the control circuit can accurately collect whether the first voltage at the first detection point is a positive voltage signal or a negative voltage signal, the condition of signal loss is avoided, the reliability of broken wire detection is improved, the control circuit can detect broken wires between the ground wires of electric equipment and the ground wires of the charging device through the bias voltage, the problem that the existing circuit cannot directly sample the negative pressure can be solved, the broken wire detection circuit is simple in structure and can reduce cost. In addition, the power supply loop is controlled to be in a disconnected state in the charging process, so that the influence of charging current on the ground wire disconnection detection is avoided, and the detection accuracy is improved. In some embodiments, the control circuit is further configured to determine that a disconnection fault does not exist between the ground of the electric device and the ground of the charging device when the magnitude of the bias voltage is in a first preset range, and determine that a disconnection fault exists between the ground of the electric device and the ground of the charging device when the magnitude of the bias voltage is in a second preset range, where a lower limit value of the first preset range is higher than an upper limit value of the second preset range. Through the technical means, normal and broken line states are distinguished by setting different amplitude thresholds, and automatic judgment on whether broken line faults exist between the ground lines is realized. On the other hand, compared with the traditional mode of judging by only depending