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CN-122000835-A - Micro-power consumption self-resetting overvoltage and undervoltage delay protection method and system

CN122000835ACN 122000835 ACN122000835 ACN 122000835ACN-122000835-A

Abstract

The invention discloses a micro-power consumption self-resetting overvoltage and undervoltage delay protection method and system, and relates to the technical field of power protection. The method comprises the steps of isolating and sampling alternating voltage through a voltage transformer, connecting 150KΩ -400KΩ current limiting resistor in series with the primary side of the transformer, sampling 1kHz ADC by adopting an 8-bit singlechip, calculating the true effective value of the voltage by adopting integer operation every 100ms without a floating point operation unit, executing three-state machine control logic according to the voltage state, immediately releasing a relay when abnormality occurs, delaying for 10 seconds to be attracted after the normal state is recovered, and driving a magnetic latching relay by adopting double pulses. The system comprises a power supply module, a voltage sampling module, a main control module and a relay driving module, wherein the power supply module adopts a hybrid voltage stabilizing framework. The invention has the advantages that the standby power consumption of the whole machine is less than or equal to 0.5W, the power consumption configuration of 0.24W-0.46W is realized by selecting different current limiting resistors, the power consumption configuration is reduced by 62-84% compared with the traditional product, the measurement precision is +/-1 V@220V, the linearity is +/-0.1%, the voltage return mechanism and the time delay reset are adopted, the power grid fluctuation misoperation is effectively prevented, the magnetic latching relay keeps the state zero power consumption, and the mechanical life is longer than 100 ten thousand times. The invention is suitable for household and small-sized equipment power supply protection application.

Inventors

  • WAN LE

Assignees

  • 万乐

Dates

Publication Date
20260508
Application Date
20260318

Claims (20)

  1. 1. A micro-power consumption self-resetting overvoltage and undervoltage delay protection method and system are characterized by comprising the following steps: S1, isolating and sampling alternating voltage through a voltage transformer, wherein the primary of the transformer is connected in series with a current limiting resistor, The secondary is connected with a load resistor in parallel; S2, carrying out ADC conversion on a sampling signal by adopting an 8-bit singlechip, wherein the sampling frequency is 1kHz; s3, calculating a true effective value of the voltage once every 100ms, and realizing square root calculation by adopting integer operation; s4, judging a voltage state according to the true effective value of the voltage, wherein the voltage state comprises a normal state, an abnormal state and a delay state; s5, immediately executing the release action of the magnetic latching relay in an abnormal state; s6, after the voltage is recovered from the abnormality to be normal, starting delay counting, and keeping a release state by the relay in the period; s7, after the delay counting is finished, executing the attraction action of the magnetic latching relay; The standby power consumption of the whole machine is less than or equal to 0.5W.
  2. 2. The micro-power consumption self-resetting overvoltage and undervoltage delay protection method as recited in claim 1, wherein the method comprises the following steps: In step S1, the resistance of the current limiting resistor is 150KΩ -400KΩ, and the resistance of the load resistor is 50Ω-1KΩ。
  3. 3. The micro-power consumption self-resetting overvoltage and undervoltage delay protection method as recited in claim 2, wherein the method comprises the following steps: The resistance of the current-limiting resistor is 200KΩ, the resistance of the load resistor is 680 Ω, the primary working current of the transformer is 0.5mA-1.5mA, and the standby power consumption of the system is 0.38W.
  4. 4. The micro-power consumption self-resetting overvoltage and undervoltage delay protection method as recited in claim 1, wherein the method comprises the following steps: in step S3, the voltage true effective value calculation formula is: Vrms = √[Σ(Vi-Vdc)2/N] × K wherein Vi is the ADC sampling value, vdc is the DC offset ADC value, N is the sampling number, and K is the scale factor.
  5. 5. The micro-power consumption self-resetting overvoltage and undervoltage delay protection method as recited in claim 4, wherein the method comprises the following steps: the scale coefficient K is determined according to the resistance value of the primary current limiting resistor, and when the current limiting resistor is 150KΩ, K=85, when the current limiting resistor is 200KΩ, K=115, when the current limiting resistor is 300KΩ, K=175, and when the current limiting resistor is 400KΩ, K=235.
  6. 6. The micro-power consumption self-resetting overvoltage and undervoltage delay protection method as recited in claim 4, wherein the method comprises the following steps: the scale factor K is determined by the following formula: K=ratio_system×vref_mv/10240 where ratio_system is the system measured power and vref_mv is the millivolt value of the ADC reference voltage.
  7. 7. The micro-power consumption self-resetting overvoltage and undervoltage delay protection method as recited in claim 1, wherein the method comprises the following steps: In the step S4, the normal state is that the voltage is within the range of 180V-250V, and the relay is in a suction state; the abnormal state is that the voltage is smaller than 180V or larger than 250V, and the relay release is immediately executed; and the delay state is that after the voltage is recovered from the abnormality to be normal, the delay counting is started for 10 seconds, and the relay is kept released during the delay counting.
  8. 8. The micro-power consumption self-resetting overvoltage and undervoltage delay protection method as recited in claim 7, wherein the method comprises the following steps: In step S4, a voltage return difference mechanism is adopted to prevent frequent actions caused by voltage fluctuation, and the undervoltage protection point is 180V, the under-voltage recovery point is 185V, the over-voltage protection point is 250V, and the over-voltage recovery point is 245V.
  9. 9. The micro-power consumption self-resetting overvoltage and undervoltage delay protection method as recited in claim 1, wherein the method comprises the following steps: In steps S5 and S7, the magnetic latching relay is driven in a double pulse mode, each pulse width is 100ms, and two pulses are separated by 50ms.
  10. 10. The micro-power consumption self-resetting overvoltage and undervoltage delay protection method as recited in claim 1, wherein the method comprises the following steps: in step S3, the square root calculation is implemented by using integer arithmetic, which specifically includes storing the square sum of ac components using 32-bit unsigned integers, and calculating the square root by using a bitwise heuristic, where the whole process does not involve floating point arithmetic instructions.
  11. 11. The micro-power consumption self-resetting overvoltage and undervoltage delay protection method as recited in claim 1, wherein the method comprises the following steps: in step S2, the ADC sampling is triggered by using timer interrupt, the interrupt period is 1ms, 100 points of continuous sampling are stored in the ring buffer, the ready flag is set after the sampling is completed, and the main cycle queries the flag to process data.
  12. 12. The micro-power consumption self-resetting overvoltage and undervoltage delay protection method as recited in claim 1, wherein the method comprises the following steps: the method also comprises a testing step, wherein the DC voltage is set in the ADC detection circuit through the testing key to simulate the abnormal voltage state.
  13. 13. The micro-power consumption self-resetting overvoltage and undervoltage delay protection method as recited in claim 1, wherein the method comprises the following steps: The alarm step is also included, and an alarm prompt is sent out through the buzzer in the undervoltage, overvoltage or delay state.
  14. 14. The micro-power consumption self-resetting overvoltage and undervoltage delay protection method as recited in claim 1, wherein the method comprises the following steps: The method also comprises a display step of displaying the voltage interval value and the relay state through the LEDs.
  15. 15. A micropower self-resetting overvoltage undervoltage delay protection system for realizing any one of claims 1-14 The method is characterized by comprising the following steps: the power supply module is used for converting alternating current 220V input into direct current working power supply; The voltage sampling module adopts a voltage transformer for isolation sampling, the primary of the voltage sampling module is connected with a current limiting resistor in series, and the secondary of the voltage sampling module is connected with a load resistor; the main control module adopts an 8-bit singlechip and is connected with the voltage sampling module and the power supply module; the relay driving module is connected with the main control module and used for driving the magnetic latching relay; the standby power consumption of the whole system is less than or equal to 0.5W.
  16. 16. The micropower self-healing overvoltage undervoltage delay protection system of claim 15, wherein: the power supply module comprises a rectifying circuit, a first-stage DC-DC conversion circuit and a second-stage linear voltage stabilizing circuit, The first stage DC-DC conversion circuit converts the rectified high voltage direct current into 12V direct current intermediate voltage, The second-stage linear voltage stabilizing circuit converts the 12V direct-current intermediate voltage into 3.3V direct-current working voltage.
  17. 17. The micropower self-healing overvoltage undervoltage delay protection system of claim 16, wherein: the first-stage DC-DC conversion circuit adopts a micro-power consumption primary side integrated chip, no optocoupler feedback is needed, and the conversion efficiency is more than or equal to 80%.
  18. 18. The micropower self-healing overvoltage undervoltage delay protection system of claim 16, wherein: The second-stage linear voltage stabilizing circuit adopts a three-terminal voltage stabilizer, the input voltage range is 5V-30V, the output voltage is 3.3V plus or minus 5%, and the static current is less than or equal to 5mA.
  19. 19. The micropower self-healing overvoltage undervoltage delay protection system of claim 15, wherein: The resistance of the current-limiting resistor is 150KΩ -400KΩ, the current-limiting resistor with different resistance is selected to realize the configurable consumption and precision, and the standby power consumption of the system is 0.24W-0.46W.
  20. 20. The micropower self-healing overvoltage undervoltage delay protection system of claim 15, wherein: The 8-bit singlechip is internally provided with a 10-bit ADC, and the true effective value calculation is realized through an integer square root algorithm without a floating point operation unit.

Description

Micro-power consumption self-resetting overvoltage and undervoltage delay protection method and system Technical Field The invention relates to the technical field of power protection, in particular to a micro-power consumption self-resetting overvoltage and undervoltage delay protection method and system. Background The power supply scheme of the traditional household voltage protector mainly comprises the following modes: 1. The high-voltage part uses resistance-capacitance voltage reduction, which has low cost but large power consumption, usually 1W-1.5W, serious heating and poor safety; 2. the low-voltage part utilizes a high-power load resistor and a voltage stabilizing tube mode to reduce and stabilize voltage, and the load resistor and the voltage stabilizing diode consume a large amount of power; 3. The full DC-DC conversion scheme has high efficiency and high cost, and under the working condition of light load (less than 5 mA), the efficiency advantage of the secondary DC-DC chip is not obvious, but noise and peripheral elements are increased. Disadvantages of the prior art: 1. The standby power consumption is high, the long-term power-on heating is obvious, and the annual power consumption is about 7-13 degrees; 2. the power supply scheme is not optimized for the light load working condition, and the cost and the performance are not matched; 3. the voltage comparison of the operational amplifier is adopted, the measurement precision is low, the voltage is only +/-5-10V, and the anti-interference capability is poor; 4. the relay needs to be electrified for a long time to keep on-state, the power consumption is high, and the mechanical life is only about 10 ten thousand times; 5. The voltage return difference mechanism is not needed, and misoperation is easy to occur when the power grid fluctuates. According to the clear requirements of JGJ 242-2011 'electric design Specification for residential buildings' and GB 50368 'Electrical Specification for residential buildings', each set of residence should be provided with a self-recovery overvoltage and undervoltage protection electric appliance. Therefore, a self-resetting overvoltage and undervoltage protection method and system with micro power consumption, high precision and long service life are needed. Disclosure of Invention The invention aims to solve the technical problem of providing a self-resetting overvoltage and undervoltage delay protection method and system with micro power consumption, low temperature rise, high precision and long service life. In order to solve the technical problems, the invention adopts the following technical scheme: a micro-power consumption self-resetting overvoltage and undervoltage delay protection method and system comprise the following steps: s1, isolating and sampling alternating voltage through a voltage transformer, wherein a primary side of the transformer is connected in series with a current limiting resistor, and a secondary side of the transformer is connected in parallel with a load resistor; S2, carrying out ADC conversion on a sampling signal by adopting an 8-bit singlechip, wherein the sampling frequency is 1kHz; s3, calculating a true effective value of the voltage once every 100ms, and realizing square root calculation by adopting integer operation; s4, judging a voltage state according to the true effective value of the voltage, wherein the voltage state comprises a normal state, an abnormal state and a delay state; s5, immediately executing the release action of the magnetic latching relay in an abnormal state; s6, after the voltage is recovered from the abnormality to be normal, starting delay counting, and keeping a release state by the relay in the period; s7, after the delay counting is finished, executing the attraction action of the magnetic latching relay; The standby power consumption of the whole machine is less than or equal to 0.5W. Further, in step S1, the resistance of the current limiting resistor is 150kΩ -400kΩ, and the resistance of the load resistor is 50 Ω -1kΩ. Further, the resistance of the current limiting resistor is 200KΩ, the resistance of the load resistor is 680 Ω, the primary working current of the transformer is 0.5mA-1.5mA, and the standby power consumption of the system is 0.38W. Further, in step S3, the voltage true effective value calculation formula is: Vrms = √[Σ(Vi-Vdc)2/N] × K wherein Vi is the ADC sampling value, vdc is the DC offset ADC value, N is the sampling number, and K is the scale factor. Further, the scale factor K is determined according to the resistance value of the primary current limiting resistor, where k=85 when the current limiting resistor is 150kΩ, k=115 when the current limiting resistor is 200kΩ, k=175 when the current limiting resistor is 300kΩ, and k=235 when the current limiting resistor is 400kΩ. Further, the scale factor K is determined by the following formula: K = Ratio_system × Vref_mV / 10240 where ratio_system is the system me