CN-121978521-A - Contact adhesion detection circuit and method of relay and charging and discharging device

Abstract

The application discloses a contact adhesion detection circuit and method of a relay and a charging and discharging device. The contact adhesion detection circuit comprises a sampling circuit, a voltage comparison circuit and an optocoupler isolation circuit, wherein the sampling circuit is used for being connected with a relay and used for outputting sampling voltage, the voltage comparison circuit is used for comparing the sampling voltage with a preset reference voltage and outputting a comparison result, and the optocoupler isolation circuit is used for outputting a corresponding level signal according to the comparison result and used for indicating whether contacts of the relay are adhered or not. According to the application, the sampling circuit is arranged to collect the voltage of the relay, the voltage comparison circuit is used for comparing the voltage with the reference voltage, and finally the optocoupler isolation circuit outputs a level signal indicating whether the contact is stuck or not, so that the effective detection of the sticking state of the contact of the relay is realized. The detection circuit has the advantages of simple structure and high response speed, can monitor the working state of the relay in real time, realizes electrical isolation, improves the safety and the anti-interference capability, ensures the accuracy and the reliability of a detection result, and avoids potential safety hazards.

Inventors

• LIU WEI
• LIN YUAN
• TIAN YUWEI

Assignees

• 深圳巴斯巴科技发展股份有限公司

Dates

Publication Date

20260505

Application Date

20260309

Claims (10)

1. 1. A contact adhesion detection circuit of a relay, comprising: the sampling circuit is used for connecting at least one relay, collecting and converting voltages at two ends of the relay and outputting sampling voltages, wherein the relay is arranged between a power supply and a load; the input end of the voltage comparison circuit is connected with the output end of the sampling circuit and is used for comparing the sampled voltage with a preset reference voltage and outputting a comparison result; And the input end of the optical coupling isolation circuit is connected with the output end of the voltage comparison circuit and is used for outputting a corresponding level signal according to the comparison result, and the level signal is used for indicating whether contacts of the relay are adhered or not.
2. 2. The contact adhesion detection circuit of claim 1, wherein the number of relays is two, including a first relay for being disposed between a positive pole of the power supply and a positive pole of the load, and a second relay for being disposed between a negative pole of the power supply and a negative pole of the load.
3. 3. The contact adhesion detection circuit of claim 2, wherein the sampling circuit comprises a first sampling unit and a second sampling unit, the voltage comparison circuit comprises a first voltage comparison unit and a second voltage comparison unit, the optocoupler isolation circuit comprises a first optocoupler isolation unit and a second optocoupler isolation unit, the sampled voltages comprise a first sampled voltage and a second sampled voltage; The input end of the first sampling unit is used for being connected with the first relay, the output end of the first sampling unit is connected with the input end of the first voltage comparison unit, and the output end of the first voltage comparison unit is connected with the input end of the first optocoupler isolation unit; the first sampling unit is used for collecting and converting the voltages at two ends of the first relay and outputting the first sampling voltage; the first optical coupler isolation unit is used for outputting a first level signal according to the comparison result, and the first level signal is used for indicating whether contacts of the first relay are adhered or not; The input end of the second sampling unit is used for being connected with the second relay, the output end of the second sampling unit is connected with the input end of the second voltage comparison unit, and the output end of the second voltage comparison unit is connected with the input end of the second optocoupler isolation unit; The second sampling unit is used for collecting and converting voltages at two ends of the second relay and outputting a second sampling voltage, the second voltage comparison unit is used for comparing the second sampling voltage with the reference voltage and outputting a comparison result, and the second optocoupler isolation unit is used for outputting a second level signal according to the comparison result and indicating whether contacts of the second relay are adhered or not.
4. 4. The contact adhesion detection circuit of claim 3, wherein the first sampling unit comprises at least one first voltage dividing resistor, a first end of the first voltage dividing resistor is used for being connected with the first relay, and a second end of the first voltage dividing resistor is connected with an input end of the first voltage comparison unit; the second sampling unit comprises at least one second voltage dividing resistor, a first end of the second voltage dividing resistor is used for being connected with the second relay, and a second end of the second voltage dividing resistor is connected with the input end of the second voltage comparison unit.
5. 5. The contact adhesion detection circuit of claim 3, wherein the first voltage comparison unit comprises a first voltage comparator, a non-inverting input terminal of the first voltage comparator is connected with an output terminal of the first sampling unit, an inverting input terminal of the first voltage comparator is used for inputting the reference voltage, and an output terminal of the first voltage comparator is connected with an input terminal of the first optocoupler isolation unit; The second voltage comparison unit comprises a second voltage comparator, the non-inverting input end of the second voltage comparator is used for inputting the reference voltage, the inverting input end of the second voltage comparator is connected with the output end of the second sampling unit, and the output end of the second voltage comparator is connected with the input end of the second optocoupler isolation unit.
6. 6. The contact adhesion detection circuit of claim 3, wherein the first optocoupler isolation unit comprises a first optocoupler, a first input end of the first optocoupler is connected to an output end of the first voltage comparison unit, a second input end of the first optocoupler is used for being connected to a first direct current power supply, a first output end of the first optocoupler is used for outputting the first level signal, and a second output end of the first optocoupler is grounded; The second optocoupler isolation unit comprises a second optocoupler, a first input end of the second optocoupler is connected with an output end of the second voltage comparison unit, a second input end of the second optocoupler is used for being connected with the first direct-current power supply, a first output end of the second optocoupler is used for outputting the second level signal, and a second output end of the second optocoupler is grounded.
7. 7. The contact adhesion detection circuit of any one of claims 1-6, further comprising a control circuit coupled to an output of the optocoupler isolation circuit, the control circuit configured to determine whether contacts of the relay are adhered based on the level signal.
8. 8. A contact adhesion detection method of a relay, characterized by being applied to the contact adhesion detection circuit of any one of claims 1 to 7, the method comprising the steps of: acquiring the voltages at two ends of the relay and converting the voltages into sampling voltages; Comparing the sampled voltage with a preset reference voltage to obtain a comparison result; outputting a corresponding level signal according to the comparison result; and judging whether contacts of the relay are adhered or not according to whether the level signal is high level or low level.
9. 9. The contact adhesion detection method of claim 8, wherein the determining whether the contacts of the relay are adhered according to whether the level signal is high or low comprises: if the level signal is high level, judging that the contacts of the relay are adhered; And if the level signal is at a low level, judging that the contact of the relay is not adhered.
10. 10. A charge and discharge device comprising at least one relay and a contact adhesion detection circuit of the relay according to any one of claims 1 to 7, the relay being connected to the contact adhesion detection circuit.

Description

Contact adhesion detection circuit and method of relay and charging and discharging device Technical Field The invention relates to the technical field of electric switch detection, in particular to a contact adhesion detection circuit and method of a relay and a charging and discharging device. Background In an electronic control system, a relay is used as a common electrical switch and is widely applied to equipment in the fields of power supplies, energy storage, inverters and the like, so that remote control of circuit on-off is realized. When the relay runs in the environments of continuous operation for a long time and severe working conditions, adhesion faults are easy to occur to the contacts, the contacts cannot be normally disconnected, the faults can cause failure of circuit on-off control, equipment cannot normally work, safety accidents such as circuit short circuit and overcurrent are easier to cause, and therefore real-time and accurate monitoring of the adhesion state of the relay is a key link for guaranteeing stable and safe operation of a power electronic system. In the prior art, aiming at the detection scheme of relay adhesion, the defects of complex circuit design, large number of sensors and signal processing components are needed to be additionally arranged, the hardware cost of a system is greatly increased, the additional circuits and the sensors occupy large amount of installation space, the system is large in size and difficult to adapt to the application scene of power equipment with limited space, the special power supply module and the complex signal processing circuit continuously consume electric energy, the overall power consumption of the system is improved, the detection result is highly dependent on the precision of the sensors, the drift and error of the sensors easily cause limited detection precision of adhesion states, the actual working state of the relay cannot be accurately identified, and the complex circuit topology structure greatly improves the maintenance and repair and fault diagnosis difficulty of the system, and the operation and maintenance cost of the later stage is increased. Disclosure of Invention The invention provides a contact adhesion detection circuit and method of a relay and a charging and discharging device, which solve the problems of high cost, large system volume, high power consumption, limited detection precision and difficult maintenance of the existing relay adhesion detection scheme. The technical scheme includes that the contact adhesion detection circuit comprises a sampling circuit, a voltage comparison circuit and an optocoupler isolation circuit, wherein an input end of the sampling circuit is used for being connected with at least one relay and used for collecting and converting voltages at two ends of the relay and outputting sampling voltages, the relay is arranged between a power supply and a load, the input end of the voltage comparison circuit is connected with an output end of the sampling circuit and used for comparing the sampling voltages with preset reference voltages and outputting comparison results, and the input end of the optocoupler isolation circuit is connected with an output end of the voltage comparison circuit and used for outputting corresponding level signals according to the comparison results and the level signals are used for indicating whether contacts of the relay are adhered or not. In some embodiments, the number of relays is two, including a first relay for being disposed between the positive pole of the power supply and the positive pole of the load and a second relay for being disposed between the negative pole of the power supply and the negative pole of the load. In some embodiments, the sampling circuit comprises a first sampling unit and a second sampling unit, the voltage comparison circuit comprises a first voltage comparison unit and a second voltage comparison unit, the optocoupler isolation circuit comprises a first optocoupler isolation unit and a second optocoupler isolation unit, the sampled voltage comprises a first sampled voltage and a second sampled voltage, the input end of the first sampling unit is used for being connected with a first relay, the output end of the first sampling unit is connected with the input end of the first voltage comparison unit, the output end of the first voltage comparison unit is connected with the input end of the first optocoupler isolation unit, the first sampling unit is used for collecting and converting voltages at two ends of the first relay and outputting a first sampled voltage, the first voltage comparison unit is used for comparing the first sampled voltage with a reference voltage and outputting a comparison result, the first optocoupler isolation unit is used for outputting a first level signal according to the comparison result, the first level signal is used for indicating whether contacts of the first relay are adhered, the input end of