CN-116540143-B - AC charging pile and mode two cable upper box controller grounding detection method

CN116540143BCN 116540143 BCN116540143 BCN 116540143BCN-116540143-B

Abstract

The invention belongs to the field of grounding detection, and relates to a grounding detection method of an alternating-current charging pile and a mode two-cable upper box controller, which comprises the steps of setting a normal threshold value of a grounding resistance and an abnormal threshold value of the grounding resistance; the method comprises the steps of acquiring voltage of an alternating current voltage acquisition circuit by an MCU to obtain single-phase alternating current voltage, wherein a voltage peak value corresponding to the single-phase alternating current voltage is a single-phase alternating current voltage peak value, acquiring voltage of a PE acquisition circuit by the MCU to obtain PE voltage, wherein the peak value sampled by the PE acquisition circuit is a PE voltage peak value, when the resistance value of a grounding resistor is equal to a normal threshold value of the grounding resistor, the peak value sampled by the PE acquisition circuit is a PE voltage normal peak value, when the resistance value of the grounding resistor is equal to an abnormal threshold value of the grounding resistor, the peak value sampled by the PE acquisition circuit is a PE voltage abnormal peak value, establishing an index table according to the single-phase alternating current voltage or the single-phase alternating current voltage peak value, and acquiring the PE voltage peak value according to the index table to judge whether grounding is good. Reliable ground detection is enabled.

Inventors

HUO JUNCHAO
LI ZHANGONG
HUANG DONGJIE
XU CHAO

Assignees

深圳市京泉华智能电气有限公司

Dates

Publication Date: 20260512
Application Date: 20230428

Claims (10)

1. An alternating-current charging pile and a method for detecting grounding of a two-cable upper box controller are characterized by comprising the following steps: setting a normal threshold value of the grounding resistor and an abnormal threshold value of the grounding resistor; the MCU acquires the voltage of the alternating current voltage acquisition circuit to obtain single-phase alternating current voltage, the voltage peak value corresponding to the single-phase alternating current voltage is a single-phase alternating current voltage peak value, the MCU acquires the voltage of the PE acquisition circuit to obtain PE voltage, and the peak value sampled by the PE acquisition circuit is a PE voltage peak value; when the resistance value of the grounding resistor is equal to the normal threshold value of the grounding resistor, the peak value sampled by the PE acquisition circuit is a PE voltage normal peak value, and when the resistance value of the grounding resistor is equal to the abnormal threshold value of the grounding resistor, the peak value sampled by the PE acquisition circuit is a PE voltage abnormal peak value; establishing an index table according to the single-phase alternating voltage or the single-phase alternating voltage peak value, and taking the PE voltage normal peak value and the PE voltage abnormal peak value as index items; According to the single-phase alternating-current voltage peak value, finding a corresponding serial number in an index table, and obtaining a PE voltage peak value; If the PE voltage peak value is greater than the PE voltage normal peak value, judging that the current grounding is good, and if the PE voltage peak value is less than the PE voltage abnormal peak value, judging that the current grounding is bad; the PE voltage refers to the voltage between PE and the voltage added value of the alternating current signal L and the alternating current signal N after capacitive impedance.
2. The method for detecting the ground connection of the ac charging pile and the second-mode cable-on-box controller according to claim 1, further comprising, before the step of setting the normal threshold value of the ground resistance and the abnormal threshold value of the ground resistance, the steps of: The alternating-current voltage acquisition circuit is connected into an ADC port of the MCU in a voltage division conversion mode, an L terminal and an N terminal in the PE acquisition circuit are subjected to capacitive isolation and resistance voltage division, and after capacitive filtering, the alternating-current voltage acquisition circuit is connected into the ADC port of the MCU through the PE_ADC, and the PE terminal is connected with the ground through a grounding resistor.
3. The method for detecting the grounding of the alternating-current charging pile and the two-cable upper box controller according to claim 1, wherein the step of acquiring the voltage of the alternating-current voltage acquisition circuit by the MCU to obtain the single-phase alternating-current voltage comprises the following steps: The MCU is used for collecting the voltage of the alternating current voltage collecting circuit; and judging whether the voltage acquired by the MCU is in the effective voltage range, if so, reserving, otherwise, discarding.
4. The AC charging pile and the method for detecting the grounding of the two-cable upper box controller according to claim 1, wherein the AC voltage acquisition circuit comprises a first amplifying circuit, a second amplifying circuit and a first isolating circuit which are electrically connected in sequence, wherein the first amplifying circuit is used for lifting an L AC signal by 2.5V of reference voltage, the second amplifying circuit is used for lifting an N AC signal by 2.5V of reference voltage, and the first isolating circuit is used for isolating the L AC signal from the N AC signal and then is connected to an ADC interface of the MCU.
5. The alternating current charging pile and two-cable upper box controller grounding detection method according to claim 1 is characterized in that the PE acquisition circuit comprises a second isolation circuit, a voltage dividing circuit and a PE voltage detection circuit which are electrically connected in sequence, wherein the second isolation circuit is used for isolating direct current from an alternating current incoming line L terminal and an alternating current incoming line N terminal, the voltage dividing circuit is used for resistor voltage division, and the PE voltage detection circuit is used for detecting voltage of one end of a sampling resistor R5 relative to analog ground.
6. The method for detecting the grounding of the AC charging pile and the second cable upper box controller according to claim 4, wherein the first amplifying circuit comprises a non-inverting input end of the amplifier U42A connected with one end of the capacitor C2, an inverting input end of the amplifier U42A connected with one end of the resistor R3 and one end of the resistor R4 respectively, the other end of the resistor R3 connected with one end of the resistor R2, the other end of the resistor R2 connected with one end of the resistor R1, the other end of the resistor R1 connected with one end of the capacitor C1, a positive power end of the amplifier U42A connected with one end of the capacitor C3, and the other end of the resistor R4 connected with the output end of the amplifier U42A.
7. The method for detecting the grounding of the AC charging pile and the second cable upper box controller according to claim 4, wherein the second amplifying circuit comprises a non-inverting input end of the amplifier U42B is connected with one end of the capacitor C5 and one end of the capacitor C4 respectively, an inverting input end of the amplifier U42B is connected with one end of the resistor R5, one end of the resistor R8 and one end of the resistor R9 respectively, the other end of the resistor R8 is connected with one end of the resistor R7, the other end of the resistor R7 is connected with one end of the resistor R6, and the other end of the resistor R6 is connected with one end of the capacitor C6.
8. The method for detecting the ground fault of the AC charging post and the second cable upper box controller according to claim 4, wherein the first isolation circuit comprises a resistor R10, one end of which is connected with one end of a capacitor C6 and a pin 3 of a double diode D1 respectively, and the other end of the capacitor C6 is connected with the pin 1 of the double diode D1.
9. The method for detecting the grounding of the AC charging pile and the two-cable upper box controller according to claim 5, wherein the voltage dividing circuit comprises a resistor R1, a resistor R2, a resistor R3 and a resistor R4 which are connected in series.
10. The method for detecting the grounding of the AC charging pile and the second-mode cable upper box controller according to claim 5, wherein the PE voltage detection circuit comprises a resistor R5, one end of which is respectively connected with a pin 3 of the double diode D1 and one end of a capacitor C3.

Description

AC charging pile and mode two cable upper box controller grounding detection method Technical Field The invention relates to the technical field of grounding detection, in particular to an alternating-current charging pile and a grounding detection method of a mode two-cable upper box controller. Background The single-phase ac charging pile and the two-cable-on-box controller must have good grounding for safety. The bad grounding must be found out in time and handled in time, otherwise, the phenomenon of electric leakage can occur when the bad grounding occurs. If the subsequent leakage detection cannot work reliably, personal safety accidents are liable to be caused. The existing grounding detection circuit of the AC charging pile of the single-phase AC pile and the two-cable upper box controller or the AC charging pile of the two-cable upper box controller and the grounding detection circuit of the two-cable upper box controller have the following problems that the poor grounding can be reliably detected within a certain range, but when the voltage exceeds a certain range, the detection is unstable or even can not be detected, so that potential safety hazards can be caused. Disclosure of Invention The invention aims to solve the technical problems that an existing single-phase alternating-current pile alternating-current charging pile and a mode two-cable upper box controller grounding detection circuit or a mode two-cable upper box controller alternating-current charging pile and a mode two-cable upper box controller grounding detection circuit are unstable in detection or even cannot detect when the voltage exceeds a certain range, so that potential safety hazards are caused. Aiming at the defects in the prior art, the grounding detection method for the alternating-current charging pile and the two-cable-on-box controller comprises the following steps: setting a normal threshold value of the grounding resistor and an abnormal threshold value of the grounding resistor; the MCU acquires the voltage of the alternating current voltage acquisition circuit to obtain single-phase alternating current voltage, the voltage peak value corresponding to the single-phase alternating current voltage is a single-phase alternating current voltage peak value, the MCU acquires the voltage of the PE acquisition circuit to obtain PE voltage, and the peak value sampled by the PE acquisition circuit is a PE voltage peak value; when the resistance value of the grounding resistor is equal to the normal threshold value of the grounding resistor, the peak value sampled by the PE acquisition circuit is a PE voltage normal peak value, and when the resistance value of the grounding resistor is equal to the abnormal threshold value of the grounding resistor, the peak value sampled by the PE acquisition circuit is a PE voltage abnormal peak value; establishing an index table according to the single-phase alternating voltage or the single-phase alternating voltage peak value, and taking the PE voltage normal peak value and the PE voltage abnormal peak value as index items; According to the single-phase alternating-current voltage peak value, finding a corresponding serial number in an index table, and obtaining a PE voltage peak value; if the PE voltage peak value is greater than the PE voltage normal peak value, judging that the current grounding is good, and if the PE voltage peak value is less than the PE voltage abnormal peak value, judging that the current grounding is bad. Preferably, before the step of setting the normal threshold value of the ground resistance and the abnormal threshold value of the ground resistance, the method further comprises the steps of: the alternating-current voltage acquisition circuit is connected into an ADC port of the MCU in a voltage division conversion mode, an L terminal and an N terminal in the PE acquisition circuit are isolated through a capacitor, the resistance is divided, the alternating-current voltage acquisition circuit is connected into the ADC port of the MCU through EC, and the PE terminal is connected with the ground through a grounding resistor. Preferably, the step of acquiring the voltage of the ac voltage acquisition circuit by the MCU to obtain a single-phase ac voltage specifically includes: The MCU is used for collecting the voltage of the alternating current voltage collecting circuit; and judging whether the voltage acquired by the MCU is in the effective voltage range, if so, reserving, otherwise, discarding. Preferably, the sampling precision of the voltage of the MCU acquisition alternating voltage acquisition circuit is 0.1V, 1V or 5V. Preferably, the alternating voltage acquisition circuit comprises a first amplifying circuit, a second amplifying circuit and an isolating circuit which are electrically connected in sequence, wherein the first amplifying circuit is used for lifting an L alternating signal by 2.5V of reference voltage, the second amplifying circuit is use