CN113848509B - Self-checking device and self-checking method for electric leakage of charging equipment - Google Patents
Self-checking device and self-checking method for electric leakage of charging equipment Download PDFInfo
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Abstract
The invention discloses a self-checking device for electric leakage of charging equipment, which comprises: the device comprises a leakage current simulation circuit, a leakage current detection circuit, a control circuit and a relay control circuit; the control circuit controls the leakage current simulation circuit to simulate leakage current, the leakage current detection circuit samples the leakage current to obtain a sampling signal of the leakage current, whether the leakage current detection function is normal or not is based on the sampling signal value, if so, the control circuit of the relay is controlled to be communicated with the charging power supply circuit, and otherwise, the control circuit of the relay is controlled to disconnect the charging power supply circuit. The invention realizes the generation of the simulated leakage current, collects the generated simulated leakage current, if the simulated leakage current is abnormal, disconnects the relay connected in series on the fire zero line, further disconnects the power supply to the subsequent-stage charging equipment, can ensure the long-term stable operation of the leakage current protector, and acts in time when the leakage protection scene really occurs.
Description
Technical Field
The invention belongs to the technical field of electric automobile charging, and particularly relates to a charging equipment leakage self-checking device and a charging equipment leakage self-checking method.
Background
In recent years, the propulsion of new energy electric vehicles accords with national policies and industry development trends, and along with the development of new energy vehicle technologies, a low-power direct current charging technical scheme is gradually approved by a host factory, so that the new energy electric vehicles become a trend; the mobile low-power direct-current charger is a popular charging mode, and the power supply plug can be directly connected to the mains supply to obtain electricity.
In the charging process of an electric automobile, the mobile low-power direct-current charger needs to have a leakage current protection function, and the general requirements of a leakage current protection electric appliance point out that the leakage current protector should be provided with a test device, and the leakage current with the current not exceeding the preset current is conducted under the rated voltage through simulation so as to periodically test the action capability of the residual current protection electric appliance.
Based on the above, a method for realizing the leakage current self-checking function of the charging connection device of the electric automobile is studied, and the safety problem can be effectively solved.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provides a leakage self-checking device for charging equipment, which simulates leakage current generation and judges collected leakage current data and periodically performs leakage current self-checking.
In order to solve the technical problems, the invention provides the following technical scheme.
In a first aspect, the present invention provides a device for self-checking leakage of a charging device, including: the device comprises a leakage current simulation circuit, a leakage current detection circuit, a control circuit and a relay control circuit;
the leakage current simulation circuit, the leakage current detection circuit and the relay control circuit are respectively connected with the control circuit;
The leakage current simulation circuit is used for simulating leakage current through control of the control circuit;
the leakage current detection circuit is used for sampling leakage current to obtain a sampling signal of the leakage current;
the relay control circuit is used for controlling the on-off of the charging power supply circuit;
the control circuit is used for controlling the leakage current simulation circuit to simulate leakage current and collecting sampling signals of the leakage current, controlling the relay control circuit to connect the charging power supply circuit if the leakage current detection function is normal based on the sampling signal value, otherwise controlling the relay control circuit to disconnect the charging power supply circuit.
Optionally, the leakage current analog circuit includes: resistor R1, resistor R2, resistor R3, resistor R4, capacitor C1, capacitor C2, transistor Q1 and transistor Q2;
one end of a resistor R3 is used as a first PWM wave input end to be connected with PWM waves xtc +, the other end of the resistor R3 is connected with the base electrode of a triode Q1, the emitter electrode of the triode Q1 is grounded, a capacitor C1 is connected between the base electrode and the emitter electrode of the triode Q1, and a power supply VCC is connected behind a collector electrode string resistor R1 of the triode Q1;
One end of a resistor R4 is used as a second PWM wave input end to be connected with a PWM wave xtc-, the PWM waves xtc + and xtc-are PWM waves with high and low level complementation, the other end of the resistor R4 is connected with a base electrode of a triode Q2, an emitter electrode of the triode Q2 is grounded, a capacitor C2 is connected between the base electrode and the emitter electrode of the triode Q2, a collector electrode of the triode Q2 is connected with a power supply VCC after being connected with the resistor R2 in series, an electric connection point between the resistor R1 and the collector electrode of the triode Q1 is used as an output end of analog leakage current, and an electric connection point between the resistor R2 and the collector electrode of the triode Q2 is used as another output end of analog leakage current;
The two output ends of the analog leakage current are connected through a wire, and the wire penetrates through the leakage current transformer so that the leakage current detection circuit can collect leakage current.
Optionally, the leakage current detection circuit includes a sampling resistor and a differential amplifying circuit connected, where the sampling resistor includes a resistor R16, and the differential amplifying circuit includes: resistor R15, resistor R19, capacitor C6, capacitor C8, resistor R17, resistor R20, resistor R13, resistor R22, capacitor C7, operational amplifier IC1, resistor R18 and resistor C9;
the two output ends of leakage current are connected to two ends of a resistor R16, one end of the resistor R16 is connected with a resistor R15, the other end of the resistor R15 is connected with a capacitor C6 and a resistor R17, the other end of the capacitor C6 is grounded, the other end of the resistor R16 is connected with a resistor R19, the other end of the resistor R19 is connected with a capacitor C8 and a resistor R20, the other end of the capacitor C8 is grounded, the other end of the resistor R17 is connected with a resistor R13 and an in-phase input end of the operational amplifier IC1, the other end of the resistor R13 is connected with a reference voltage Vbias, the capacitor C7 is connected between the in-phase input end and the in-phase input end of the operational amplifier IC1 in parallel, the other end of the resistor R22 is connected with the output end of the operational amplifier IC1, the output end of the operational amplifier IC1 is connected with one end of the resistor R18, the other end of the resistor R18 is connected with a capacitor C9, and the other end of the capacitor C9 is grounded; the junction between resistor R18 and capacitor C9 serves as the output of the differential amplifier circuit, i.e., the sampled voltage signal ai_rct of the leakage current.
Optionally, the relay control circuit includes: resistor R7, diode D1, relay K1, MOS pipe Q3, resistor R9, resistor R11 and capacitor C3;
one end of a resistor R9 is used as a control signal input end to be connected with a control signal Rly_Ctrl, the other end of the resistor R9 is simultaneously connected with a G pole of a MOS tube Q3, one end of a capacitor C3 and one end of a resistor R11, the other end of the capacitor C3 and the other end of the resistor R11 are both grounded, the S pole of the MOS tube Q3 is grounded, the D pole of the MOS tube Q3 is simultaneously connected with an anode of a diode D1 and one input end of a relay K1, the cathode of the diode D1 is simultaneously connected with one end of a resistor R7 and the other input end of the relay K1, the other end of the resistor R7 is connected with a power supply, one output end of the relay K1 is connected with one end L_in of a charging power supply wire, and the other output end of the relay K1 is connected with the other end L_out of the charging power supply wire;
when the control signal Rly_Ctrl is at a low level, the relay K1 is disconnected, so that two ends of the charging power supply line are disconnected;
When the control signal rly_ctrl is at a high level, the relay K1 is closed, so that both ends of the charging power supply line are connected.
Optionally, the charging power supply line is a live wire or a neutral wire.
Optionally, the control circuit comprises a single chip microcomputer.
Optionally, the method further comprises: and the LED indicator lamp control circuit is used for indicating whether the leakage current detection function is normal or not.
Optionally, the LED indicator control circuit includes: resistor R5, green indicator light LED1, resistor R6, red indicator light LED2;
the indicator lamp control signal LED_Ctrl is connected to one end of the resistor R5 and one end of the resistor R6, the other end of the resistor R5 is connected with the cathode of the green indicator lamp LED1, the anode of the green indicator lamp LED1 is connected with the power VCC, the other end of the resistor R6 is connected with the anode of the red indicator lamp LED2, and the cathode of the red indicator lamp LED2 is grounded;
When the leakage current detection function is normal, the green indicator light LED1 is controlled to be on, and when the leakage current detection function is abnormal, the red indicator light LED2 is controlled to be on.
In a second aspect, a leakage self-checking method based on the leakage self-checking device of charging equipment includes the following steps:
Simulating leakage current;
collecting sampling signals of leakage current;
judging whether the leakage current detection function is normal or not based on the leakage current sampling signal value, if so, connecting the charging power supply circuit, otherwise, disconnecting the charging power supply circuit.
Optionally, the simulating the leakage current includes:
two paths of PWM waves with high and low level complementation are output to the leakage current analog circuit, and leakage current signals are formed on the lead wire passing through the leakage current transformer due to the fact that the triodes Q1 and Q2 are not conducted simultaneously.
Optionally, the determining whether the leakage current detection function is normal based on the leakage current sampling signal value includes:
comparing the leakage current sampling signal value with a set threshold value;
If the leakage current detection value is larger than the threshold value, the leakage current detection function is normal; if the current is lower than the threshold value, the leakage current detection function is abnormal.
Compared with the prior art, the invention has the following beneficial effects: the invention regularly simulates the generation of leakage current, collects the generated simulation leakage current and transmits the simulation leakage current to a control circuit for judgment; if the power supply is abnormal, the relay connected in series on the fire zero line is disconnected, and then the power supply to the subsequent-stage charging equipment is disconnected; meanwhile, leakage current self-checking can be carried out regularly, and a test device is not required to be triggered manually every month like a traditional leakage current protector. The invention can ensure the long-term stable operation of the leakage current protector and act in time when the leakage protection scene really occurs.
Drawings
FIG. 1 is a control system composition for self-checking the leakage of a charging device;
FIG. 2 is a schematic diagram of a leakage current analog circuit;
FIG. 3 is a schematic diagram of a leakage current detection circuit;
FIG. 4 is a schematic diagram of a control circuit of an LED indicator lamp;
FIG. 5 is a schematic diagram of a relay control circuit;
Fig. 6 is a simulated complementary PWM waveform.
Detailed Description
The invention is further described below with reference to the accompanying drawings. The following examples are only for more clearly illustrating the technical aspects of the present invention, and are not intended to limit the scope of the present invention.
In the description of the present patent, it should be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that elements are listed and may include other elements not expressly listed.
In the description of the present patent, it should be noted that, directions or positional relationships indicated by terms such as "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., are based on directions or positional relationships shown in the drawings, are merely for convenience of describing the present patent and simplifying the description, and do not indicate or imply that the apparatus or elements to be referred to must have a specific direction, be configured and operated in a specific direction, and thus should not be construed as limiting the present patent. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the present patent, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the terms in the present patent will be understood by those skilled in the art in specific cases.
The invention is characterized in that: in the process of charging a vehicle by a mobile low-power charger, when the charging equipment is electrified, a symmetrical PWM wave xtc + and xtc-is simulated and output by a singlechip control system, the frequency is 50Hz, signals are converted into sine waves tc+ and tc-through a circuit consisting of triode resistors and the like, the sine waves tc+ and tc-pass through a leakage current transformer and are sent to an ADC pin of the singlechip control system after being amplified by a sampling resistor and a difference, and the singlechip control system judges the collected leakage current. If the leakage current is in the reasonable range, judging that the leakage current passes the self-test, controlling the green LED to be on, and enabling the relay to be on, wherein the charging equipment normally outputs commercial power to charge the load; if leakage current or abnormal leakage current is detected, judging that the leakage current self-test is not passed, controlling the red LED to be on, switching off a relay connected in series on a fire zero line, disconnecting the charging equipment from a load, and not charging.
The embodiment of the invention provides a self-checking device for leakage of charging equipment, which is shown in fig. 1, and comprises: the LED display device comprises a leakage current simulation circuit, a leakage current detection circuit, a singlechip control circuit, an LED indicator lamp control circuit and a relay control circuit.
The following describes each circuit in detail:
1) Leakage current analog circuit
The single chip microcomputer control system simulates and outputs symmetrical PWM waves xtc & lt+ & gt and xtc & lt- & gt with the frequency of 50Hz, and converts signals into sine waves tc & lt- & gt and tc & lt- & gt to be output through a leakage current simulation circuit.
FIG. 2 is a schematic diagram of a leakage current analog circuit; the leakage current simulation circuit comprises a power VCC access end, a resistor R1, a resistor R2, a resistor R3 and a resistor R4, a capacitor C1, a capacitor C2, a triode Q1 and a triode Q2, wherein the first PWM wave input end is connected with the base electrode of the triode Q1 in series after being connected with the resistor R3, the emitter electrode of the triode Q1 is grounded, the capacitor C1 is connected between the base electrode and the emitter electrode of the triode Q1, the collector electrode of the triode Q1 is connected with the power VCC access end after being connected with the resistor R1, the second PWM wave input end is connected with the base electrode of the triode Q2 in series after being connected with the resistor R4, the emitter electrode of the triode Q2 is grounded, the capacitor C2 is connected between the base electrode and the emitter electrode of the triode Q2, the collector electrode of the triode Q2 is connected with the power VCC access end after being connected with the resistor R2, the electric connection point between the resistor R1 and the collector electrode of the triode Q1 is used as one end of simulating leakage current, and the electric connection point between the resistor R2 and the collector electrode of the triode Q2 is used as the other end of simulating leakage current. The power VCC access terminal is connected with the power VCC, the first PWM wave input terminal is connected with PWM waves xtc +, and the second PWM wave input terminal is connected with PWM waves xtc-.
The working principle of the leakage current analog circuit is as follows: xtc + and xtc-are two paths of PWM signals with the same and complementary duty ratios, namely xtc-is low level when xtc + is high level, xtc-is high level when xtc + is low level, and on-off of Q1 and Q2 is controlled through high and low levels of the PWM signals; tc+ and tc-are connected in series in the leakage current transformer through a lead, and form a loop together with the power supply VCC, the resistor R1, the resistor R2 and the ground GND, so that a tiny current signal is generated for detection of the leakage current transformer. The current of the current signal is VCC/R1, and the resistance values of R1 and R2 are the same.
2) Leakage current detection circuit
FIG. 3 is a schematic diagram of a leakage current detection circuit; the leakage current detection circuit comprises a sampling resistor and a differential amplification circuit which are connected, wherein the sampling resistor comprises a resistor R16, the differential amplification circuit comprises a resistor R15, a resistor R19, a capacitor C6, a capacitor C8, a resistor R17, a resistor R20, a resistor R13, a capacitor C7, a resistor R22 and an operational amplifier IC1, a capacitor C5, a resistor R18 and a resistor C9, leakage current signals ct+ and ct-are connected to two ends of the resistor R16, one end of the resistor R16 is connected with the resistor R15, the other end of the resistor R15 is connected with the capacitor C6 and the resistor R17, the other end of the capacitor C6 is grounded, the other end of the resistor R16 is connected with the resistor R19, the other end of the resistor R19 is connected with the C8 and the resistor R20, the other end of the capacitor C8 is grounded, the other end of the resistor R17 is connected with the resistor R13 and the non-inverting input end of the operational amplifier IC1, the other end of the resistor R20 is connected with the inverting input end of the operational amplifier IC1, the other end of the resistor R13 is connected with 2.5V reference voltage Vbs, the other end of the resistor R22 is connected with the output end of the operational amplifier IC1, the other end of the resistor C22 is connected with the output end of the operational amplifier IC1, the resistor C1, the other end is connected with the non-inverting input end of the resistor C9, and the non-inverting input end of the capacitor C1 is connected with the non-inverting input end of the input voltage; the junction between resistor R18 and capacitor C9 serves as the output of the differential amplifier circuit, i.e., the sampled voltage signal ai_rct of the leakage current.
The working principle of the leakage current detection circuit is as follows: when the ct+ and ct-place is connected with an analog leakage current signal, the leakage current signal is converted into a tiny voltage signal through a sampling resistor R16, and the tiny voltage signal is amplified by a differential amplifying circuit and then sent to an ADC pin of the singlechip, and the reference voltage Vbias enables the voltage signal sent to the ADC pin of the singlechip to not contain negative level.
3) LED indicator lamp control circuit
FIG. 4 is a schematic diagram of a control circuit of an LED indicator lamp; the LED indicator light control circuit includes: resistor R5, green pilot lamp LED1, resistance R6, red pilot lamp LED2, pilot lamp control signal LED_ctrl is exported from the singlechip IO mouth, links in the one end of resistor R5 and the one end of resistance R6, and green pilot lamp LED 1's negative pole is connected to resistance R5's the other end, and power VCC is connected to green pilot lamp LED 1's positive pole, and red pilot lamp LED 2's positive pole is connected to resistance R6's the other end, and red pilot lamp LED 2's negative pole ground. When the detected analog leakage current signal is consistent with the designed value, the leakage current detection circuit is normal, the singlechip controls the green indicator lamp LED1 to be on, and when the detected analog leakage current signal is inconsistent with the designed value, the leakage current detection circuit is abnormal, and the singlechip controls the red indicator lamp LED2 to be on.
4) Relay control circuit
FIG. 5 is a schematic diagram of a relay control circuit; the relay control circuit includes: the device comprises a resistor R7, a diode D1, a relay K1, a MOS tube Q3, a resistor R9, a resistor R11 and a capacitor C3, wherein one end of the resistor R9 is connected with a control signal Rly_Ctrl, the other end of the resistor R9 is simultaneously connected with a G pole of the MOS tube Q3, one end of the capacitor C3 and one end of the resistor R11, the other end of the capacitor C3 and the other end of the resistor R11 are both grounded, the S pole of the MOS tube Q3 is grounded, the D pole of the MOS tube Q3 is simultaneously connected with the anode of the diode D1 and one input end of the relay K1, the cathode of the diode D1 is simultaneously connected with one end of the resistor R7 and the other input end of the relay K1, the other end of the resistor R7 is connected with a power supply 12V, one output end of the relay K1 is connected with one end L_in of a charging power line, and the other output end of the relay K1 is connected with the other end L_out of the charging power line.
The working principle of the relay control circuit is as follows: when the leakage current detection circuit fails (is abnormal), the singlechip controls the Rly_Ctrl to output a low level, so that the relay K1 connected in series on the power line (live wire) is disconnected, namely, the input and the output are disconnected. The working principle of the relay connected in series on the zero line is the same as that of the relay on the fire line, and the same control pin Rly_Ctrl can be used for control.
Fig. 6 is an analog leakage current sampling voltage signal, which is an oscilloscope actual measurement waveform, CH1 is a waveform of ai_rct, CH2 is an rly_ctrl waveform, and when the analog leakage current sampling voltage signal ai_rct is correctly transmitted to an ADC pin of the single chip microcomputer, the single chip microcomputer controls the output rly_ctrl to be changed from a low level to a high level, i.e. a waveform shown by CH 2.
The invention relates to a working process of a leakage self-checking device of charging equipment, which comprises the following steps:
1) The singlechip control system simulates and outputs two paths of PWM waves xtc + and xtc-, which are complementary in high and low levels, the frequency of the two paths of PWM waves is 50Hz, the amplitude of the two paths of PWM waves is 3.3V, and a small sine wave current signal is formed on a tc+ and tc-lead wire passing through a leakage current transformer through a leakage current simulation circuit because Q1 and Q2 are not conducted simultaneously, wherein the current of the current signal is VCC/R1, and the resistance value of R1 and R2 is the same;
2) When the leakage current transformer detects the simulated leakage current, the fixed transformation ratio CT of the leakage current transformer passes through a sampling resistor R16 and then passes through a differential amplifying circuit, the amplification factor is R13/R (R17+R15), wherein the resistance value of R13 is the same as that of R22, the resistance value of R17 is the same as that of R20, the resistance value of R15 is the same as that of R19, and finally a voltage signal ai_rct is sent to an ADC pin of a singlechip control system, the theoretical value of the voltage signal ai_rct is VCC/R1/CT x R16 x [ R13/R15 ], and the specific CT value and each resistance value can be selected according to actual conditions;
3) When the ADC pin of the singlechip control system detects the voltage signal, the voltage signal is compared with a set threshold value, and the specific threshold value can be set according to the actually simulated ai_rct voltage value. When the current is larger than the set threshold, the leakage current detection function is normal, the leakage current transformer and the leakage current detection circuit are not damaged, the green LED is controlled to be bright, the relay connected in series on the fire zero line is closed, and the charging equipment works normally; when the current is lower than the threshold value, the abnormal function of leakage current detection is indicated, the red LED needs to be controlled to be on, the relay connected in series on the fire zero line is disconnected, and the charging equipment stops charging.
The electric leakage self-checking device for the charging equipment can be applied to a direct-current charging connecting device in the prior art and comprises a power supply plug, a control unit, a direct-current charging connector and the like. The power supply plug is connected with the control unit, and the control unit is connected with the charging connector. In the use, the direct current charging connector is connected with the electric automobile, the power supply plug is connected with the commercial power socket, and the control unit monitors and controls the charging process.
In the power supply plug, a leakage current transformer and a leakage current self-checking function are arranged. The leakage current self-checking function is monitored by a leakage current detection circuit in the control unit.
The leakage current detection module of the control unit consists of a leakage current transformer, a sampling resistor, a differential amplifying circuit and a singlechip control system.
The direct current charging connecting device also comprises a display loop, wherein the display loop is arranged on the direct current charging connecting device and is controlled and displayed by the control unit.
The display loop is an indication lamp panel and a circuit thereof, and the indication lamp panel or the liquid crystal display is arranged on the surface of the control unit or the direct current charging connector.
According to the invention, whether the leakage current transformer is abnormal in the charging process of the power supply plug is monitored through the leakage current self-checking functional module of the power supply plug, when the simulated leakage current is higher or lower than a certain leakage current threshold value in self-checking, a corresponding control signal is automatically sent out to control the relay connected in series on the fire zero line to be closed or opened, so that the power supply input of the subsequent-stage charging equipment is disconnected, and a corresponding fault or alarm indication is sent out, thereby effectively avoiding the working of the leakage current transformer in an unsafe state.
According to the invention, manual tests are not required to be carried out every month like a common leakage current protector, so that more convenience is brought to users; meanwhile, the proportion of manual tests per month is extremely low, so that the leakage current protector is in a potential unsafe working state in fact, and more safety guarantee is brought to users; thereby ensuring safe charging of the electric automobile.
The foregoing is merely a preferred embodiment of the present invention, and it should be noted that it will be apparent to those skilled in the art that modifications and variations can be made without departing from the technical principles of the present invention, and these modifications and variations should also be regarded as the scope of the invention.
Claims (4)
1. Charging type equipment electric leakage self-checking device, characterized by comprising: the device comprises a leakage current simulation circuit, a leakage current detection circuit, a control circuit and a relay control circuit;
the leakage current simulation circuit, the leakage current detection circuit and the relay control circuit are respectively connected with the control circuit;
The leakage current simulation circuit is used for simulating leakage current through control of the control circuit;
the leakage current detection circuit is used for sampling leakage current through the leakage current transformer to obtain a sampling signal of the leakage current;
the relay control circuit is used for controlling the on-off of the charging power supply circuit;
The control circuit is used for controlling the leakage current simulation circuit to simulate leakage current and collecting sampling signals of the leakage current, controlling the relay control circuit to connect the charging power supply circuit if the leakage current detection function is normal based on the sampling signal value, otherwise controlling the relay control circuit to disconnect the charging power supply circuit;
The leakage current analog circuit includes: resistor R1, resistor R2, resistor R3, resistor R4, capacitor C1, capacitor C2, transistor Q1 and transistor Q2;
one end of a resistor R3 is used as a first PWM wave input end to be connected with PWM waves xtc +, the other end of the resistor R3 is connected with the base electrode of a triode Q1, the emitter electrode of the triode Q1 is grounded, a capacitor C1 is connected between the base electrode and the emitter electrode of the triode Q1, and a power supply VCC is connected behind a collector electrode string resistor R1 of the triode Q1;
One end of a resistor R4 is used as a second PWM wave input end to be connected with a PWM wave xtc-, the PWM waves xtc + and xtc-are PWM waves with high and low level complementation, the other end of the resistor R4 is connected with a base electrode of a triode Q2, an emitter electrode of the triode Q2 is grounded, a capacitor C2 is connected between the base electrode and the emitter electrode of the triode Q2, a collector electrode of the triode Q2 is connected with a power supply VCC after being connected with the resistor R2 in series, an electric connection point between the resistor R1 and the collector electrode of the triode Q1 is used as an output end of analog leakage current, and an electric connection point between the resistor R2 and the collector electrode of the triode Q2 is used as another output end of analog leakage current;
The two output ends of the analog leakage current are connected through a wire, and the wire passes through the leakage current transformer so that the leakage current detection circuit can collect the leakage current;
The leakage current detection circuit comprises a sampling resistor and a differential amplification circuit which are connected, wherein the sampling resistor comprises a resistor R16, and the differential amplification circuit comprises: resistor R15, resistor R19, capacitor C6, capacitor C8, resistor R17, resistor R20, resistor R13, resistor R22, capacitor C7, operational amplifier IC1, resistor R18 and resistor C9;
The two output ends of leakage current are connected to two ends of a resistor R16, one end of the resistor R16 is connected with a resistor R15, the other end of the resistor R15 is connected with a capacitor C6 and a resistor R17, the other end of the capacitor C6 is grounded, the other end of the resistor R16 is connected with a resistor R19, the other end of the resistor R19 is connected with a capacitor C8 and a resistor R20, the other end of the capacitor C8 is grounded, the other end of the resistor R17 is connected with a resistor R13 and an in-phase input end of the operational amplifier IC1, the other end of the resistor R13 is connected with a reference voltage Vbias, the capacitor C7 is connected between the in-phase input end and the in-phase input end of the operational amplifier IC1 in parallel, the other end of the resistor R22 is connected with the output end of the operational amplifier IC1, the output end of the operational amplifier IC1 is connected with one end of the resistor R18, the other end of the resistor R18 is connected with a capacitor C9, and the other end of the capacitor C9 is grounded; the connection point between the resistor R18 and the capacitor C9 is used as the output of the differential amplifying circuit, namely a sampling voltage signal ai_rct of leakage current;
the relay control circuit includes: resistor R7, diode D1, relay K1, MOS pipe Q3, resistor R9, resistor R11 and capacitor C3;
one end of a resistor R9 is used as a control signal input end to be connected with a control signal Rly_Ctrl, the other end of the resistor R9 is simultaneously connected with a G pole of a MOS tube Q3, one end of a capacitor C3 and one end of a resistor R11, the other end of the capacitor C3 and the other end of the resistor R11 are both grounded, the S pole of the MOS tube Q3 is grounded, the D pole of the MOS tube Q3 is simultaneously connected with an anode of a diode D1 and one input end of a relay K1, the cathode of the diode D1 is simultaneously connected with one end of a resistor R7 and the other input end of the relay K1, the other end of the resistor R7 is connected with a power supply, one output end of the relay K1 is connected with one end L_in of a charging power supply wire, and the other output end of the relay K1 is connected with the other end L_out of the charging power supply wire;
when the control signal Rly_Ctrl is at a low level, the relay K1 is disconnected, so that two ends of the charging power supply line are disconnected;
When the control signal Rly_Ctrl is at a high level, the relay K1 is closed, so that two ends of the charging power supply line are communicated;
The charging power supply circuit is a live wire or a zero wire;
further comprises: the LED indicator lamp control circuit is used for indicating whether the leakage current detection function is normal or not;
The LED indicator light control circuit comprises: resistor R5, green indicator light LED1, resistor R6, red indicator light LED2;
the indicator lamp control signal LED_Ctrl is connected to one end of the resistor R5 and one end of the resistor R6, the other end of the resistor R5 is connected with the cathode of the green indicator lamp LED1, the anode of the green indicator lamp LED1 is connected with the power VCC, the other end of the resistor R6 is connected with the anode of the red indicator lamp LED2, and the cathode of the red indicator lamp LED2 is grounded;
When the leakage current detection function is normal, the green indicator light LED1 is controlled to be on, and when the leakage current detection function is abnormal, the red indicator light LED2 is controlled to be on.
2. The leakage self-checking method based on the leakage self-checking device of the charging equipment as claimed in claim 1, which is characterized by comprising the following steps:
Simulating leakage current;
collecting sampling signals of leakage current;
judging whether the leakage current detection function is normal or not based on the leakage current sampling signal value, if so, connecting the charging power supply circuit, otherwise, disconnecting the charging power supply circuit.
3. The leakage self-test method according to claim 2, wherein the simulating leakage current comprises:
two paths of PWM waves with high and low level complementation are output to the leakage current analog circuit, and leakage current signals are formed on the lead wire passing through the leakage current transformer due to the fact that the triodes Q1 and Q2 are not conducted simultaneously.
4. The leakage self-checking method according to claim 2, wherein the determining whether the leakage current detection function is normal based on the leakage current sampling signal value comprises:
comparing the leakage current sampling signal value with a set threshold value;
If the leakage current detection value is larger than the threshold value, the leakage current detection function is normal; if the current is lower than the threshold value, the leakage current detection function is abnormal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111088113.8A CN113848509B (en) | 2021-09-16 | Self-checking device and self-checking method for electric leakage of charging equipment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111088113.8A CN113848509B (en) | 2021-09-16 | Self-checking device and self-checking method for electric leakage of charging equipment |
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| Publication Number | Publication Date |
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| CN113848509A CN113848509A (en) | 2021-12-28 |
| CN113848509B true CN113848509B (en) | 2024-07-02 |
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN206164168U (en) * | 2016-11-23 | 2017-05-10 | 天津航空机电有限公司 | Charging control circuit and charger |
| CN111244889A (en) * | 2020-03-17 | 2020-06-05 | 中山市格瑞斯电器有限公司 | Intelligent three-pole-breaking leakage protection plug circuit |
| CN112448364A (en) * | 2019-09-05 | 2021-03-05 | 苏州益而益电器制造有限公司 | Relay type leakage protection device |
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN206164168U (en) * | 2016-11-23 | 2017-05-10 | 天津航空机电有限公司 | Charging control circuit and charger |
| CN112448364A (en) * | 2019-09-05 | 2021-03-05 | 苏州益而益电器制造有限公司 | Relay type leakage protection device |
| CN111244889A (en) * | 2020-03-17 | 2020-06-05 | 中山市格瑞斯电器有限公司 | Intelligent three-pole-breaking leakage protection plug circuit |
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