CN107703405B - Power failure detection method for water purifier - Google Patents
Power failure detection method for water purifier Download PDFInfo
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- CN107703405B CN107703405B CN201710878199.1A CN201710878199A CN107703405B CN 107703405 B CN107703405 B CN 107703405B CN 201710878199 A CN201710878199 A CN 201710878199A CN 107703405 B CN107703405 B CN 107703405B
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- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 title claims abstract description 112
- 238000001514 detection method Methods 0.000 title claims abstract description 22
- 238000005070 sampling Methods 0.000 claims abstract description 165
- 230000000087 stabilizing effect Effects 0.000 claims abstract description 36
- 239000003990 capacitor Substances 0.000 claims description 51
- 238000004146 energy storage Methods 0.000 claims description 42
- 238000000034 method Methods 0.000 claims description 24
- 230000000151 anti-reflux effect Effects 0.000 claims description 18
- 238000012952 Resampling Methods 0.000 claims description 13
- 238000001914 filtration Methods 0.000 claims description 8
- 238000012935 Averaging Methods 0.000 claims description 5
- 230000002159 abnormal effect Effects 0.000 abstract description 7
- 238000010586 diagram Methods 0.000 description 5
- 239000008186 active pharmaceutical agent Substances 0.000 description 4
- 230000009286 beneficial effect Effects 0.000 description 2
- 230000001276 controlling effect Effects 0.000 description 2
- 230000001939 inductive effect Effects 0.000 description 2
- 230000002265 prevention Effects 0.000 description 2
- 238000013500 data storage Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/165—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values
- G01R19/16566—Circuits and arrangements for comparing voltage or current with one or several thresholds and for indicating the result not covered by subgroups G01R19/16504, G01R19/16528, G01R19/16533
- G01R19/16571—Circuits and arrangements for comparing voltage or current with one or several thresholds and for indicating the result not covered by subgroups G01R19/16504, G01R19/16528, G01R19/16533 comparing AC or DC current with one threshold, e.g. load current, over-current, surge current or fault current
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Abstract
The embodiment of the invention discloses a power failure detection method for a water purifier, wherein the water purifier comprises the following components: the system comprises a system power supply, a load, a first resistor, a second resistor, a voltage stabilizing diode and a main control chip; the main control chip is used for sampling load current or load voltage; the system power supply, the load and the first resistor are sequentially connected in series and then grounded; the voltage stabilizing diode is connected between the sampling end of the main control chip and the ground in parallel; one end of the second resistor is connected with the sampling end of the main control chip, and the other end of the second resistor is connected between the load and the first resistor; the power failure detection method of the water purifier comprises the following steps: and judging whether the water purifier is powered off or not according to the magnitude of the sampling current or the magnitude of the sampling voltage of the main control chip. Through the scheme of the embodiment, the power failure condition of the water purifier is detected in time, so that data loss and abnormal work of a machine are avoided.
Description
Technical Field
The embodiment of the invention relates to a water treatment equipment control technology, in particular to a power failure detection method for a water purifier.
Background
The existing water purifier works for a long time without power failure; data storage is often required in the working process; at this time, if the machine is powered off, data loss is easily caused, so that data inaccuracy or working state abnormity is caused.
Disclosure of Invention
The embodiment of the invention provides a power failure detection method for a water purifier, which can detect the power failure condition of the water purifier in time so as to avoid data loss and abnormal work of a machine.
In order to solve the technical problem, the embodiment of the invention adopts the following technical scheme:
a power failure detection method for a water purifier comprises the following steps: the system comprises a system power supply, a load, a first resistor, a second resistor, a voltage stabilizing diode and a main control chip; the main control chip is used for sampling load current or load voltage; the system power supply, the load and the first resistor are sequentially connected in series and then grounded; the voltage stabilizing diode is connected between the sampling end of the main control chip and the ground in parallel; one end of the second resistor is connected with the sampling end of the main control chip, and the other end of the second resistor is connected between the load and the first resistor; the power failure detection method of the water purifier comprises the following steps:
and judging whether the water purifier is powered off or not according to the magnitude of the sampling current or the magnitude of the sampling voltage of the main control chip.
Optionally, judging whether the water purifier loses power through the magnitude of the sampling current of the main control chip includes:
when the water purifier works, sampling load current, and comparing the collected first sampling current with a reference current measured in advance;
when the first sampling current is larger than or equal to the reference current, judging that the water purifier is not powered off;
when the first sampling current is smaller than the reference current, resampling the load current within a preset first time period, and comparing a second sampling current obtained by sampling with a preset current threshold; when the second sampling current is smaller than or equal to the current threshold, determining that the water purifier is powered off; and when the second sampling current is larger than the current threshold, resampling the load current, comparing the sampling current with the reference current and the current threshold again, and judging the power failure again.
Alternatively, the reference current is obtained by averaging the load current by sampling a plurality of times, and the reference current is updated by a moving average filtering method.
Alternatively,
the first time period includes: 4-7 seconds;
the current threshold includes: k times the reference current, wherein k is more than 0 and less than 1.
Optionally, judging whether the water purifier loses power through the size of the sampling voltage of the main control chip includes:
when the water purifier does not work, sampling the load voltage, and comparing the calculated first sampling voltage with a prestored reference voltage;
when the first sampling voltage is equal to the reference voltage, judging that the water purifier is not powered down;
when the first sampling voltage is smaller than the reference voltage, resampling the load voltage within a preset second time period, and comparing a second sampling voltage obtained by sampling with a preset voltage threshold value; and when the second sampling voltage is less than or equal to the voltage threshold, determining that the water purifier is powered down.
Alternatively,
the reference voltages include: the voltage of a voltage stabilizing diode is arranged at the sampling end of the main control chip;
the voltage threshold includes: n times of the reference voltage, wherein n is more than 0 and less than 1;
the second duration comprises: 4-7 seconds.
Optionally, the water purifier further comprises: the device comprises a first switch, a second switch, a freewheeling diode, a first energy storage capacitor and a filter capacitor;
the first switch is connected between the load and the first resistor in series;
the other end of the second resistor is connected between the load and the first switch;
the second switch is connected between the system power supply and the load in series;
the freewheeling diode is connected in parallel with the load;
the first energy storage capacitor and the filter capacitor are connected between the sampling end of the main control chip and the ground in parallel.
Optionally, the water purifier further comprises: the voltage stabilizing circuit, the second energy storage capacitor and the third energy storage capacitor;
the power supply input end of the voltage stabilizing circuit is connected with a system power supply; the power supply output end of the voltage stabilizing circuit is connected with the power supply input end of the main control chip;
the positive electrode of the second energy storage capacitor is connected between the system power supply and the voltage stabilizing circuit, and the negative electrode of the second energy storage capacitor is grounded;
the positive electrode of the third energy storage capacitor is connected between the voltage stabilizing circuit and the power supply input end of the main control chip, and the negative electrode of the third energy storage capacitor is grounded.
Optionally, the sum of the capacitance values of the second energy storage capacitor and the third energy storage capacitor is greater than 10 uf.
Optionally, the water purifier further comprises: an anti-reflux diode;
the anode of the anti-reflux diode is connected with a system power supply; the cathode of the anti-reflux diode is connected with the power input end of the voltage stabilizing circuit; or,
the anode of the anti-reflux diode is connected with the power output end of the voltage stabilizing circuit; the cathode of the anti-reflux diode is connected with the power input end of the main control chip.
The embodiment of the invention has the beneficial effects that:
1. the water purifier of the embodiment of the invention comprises: the system comprises a system power supply, a load, a first resistor, a second resistor, a voltage stabilizing diode and a main control chip; the main control chip is used for sampling load current or load voltage; the system power supply, the load and the first resistor are sequentially connected in series and then grounded; the voltage stabilizing diode is connected between the sampling end of the main control chip and the ground in parallel; one end of the second resistor is connected with the sampling end of the main control chip, and the other end of the second resistor is connected between the load and the first resistor; the power failure detection method of the water purifier comprises the following steps: and judging whether the water purifier is powered off or not according to the magnitude of the sampling current or the magnitude of the sampling voltage of the main control chip. According to the scheme of the embodiment of the invention, the power failure condition of the water purifier can be detected in time, so that data loss and abnormal work of a machine are avoided.
2. The embodiment of the invention judges whether the water purifier is powered off or not according to the sampling current of the main control chip, and comprises the following steps: when the water purifier works, sampling load current, and comparing the collected first sampling current with a reference current measured in advance; when the first sampling current is larger than or equal to the reference current, judging that the water purifier is not powered off; when the first sampling current is smaller than the reference current, resampling the load current within a preset first time period, and comparing a second sampling current obtained by sampling with a preset current threshold; when the second sampling current is smaller than or equal to the current threshold, determining that the water purifier is powered off; and when the second sampling current is larger than the current threshold, resampling the load current, comparing the sampling current with the reference current and the current threshold again, and judging the power failure again. According to the embodiment, the load current obtained by sampling is compared with the reference current, and the power failure condition is judged according to the comparison result, so that the method is simple, easy to understand, easy to implement, accurate and reliable.
3. In the embodiment of the invention, the reference current is obtained by sampling and averaging the load current for multiple times, and the reference current is updated by adopting a moving average filtering method. The embodiment of the scheme ensures the accuracy and reliability of the load current and further ensures the power failure detection precision.
4. The first time period in the embodiment of the invention comprises the following steps: 4-7 seconds, the time range can not cause the current after the power failure to timely drop to the preset current threshold value because of too short time, and can not cause data loss or abnormal machine work because of not timely reflecting after the power failure because of too long time, and the time range is reasonable to set, thereby ensuring the detection accuracy.
5. In the embodiment of the invention, the sum of the capacitance values of the second energy storage capacitor and the third energy storage capacitor is more than 10 uf. According to the scheme of the embodiment, when the machine is powered down, the sampling current and the sampling voltage of the sampling end of the main control chip are changed, and the input power VCC of the main control chip maintains the state before the power down.
Drawings
The invention is further described below with reference to the accompanying drawings:
fig. 1 is a schematic diagram of a first circuit of a water purifier according to an embodiment of the present invention;
FIG. 2 is a flow chart of a method for detecting power failure of a water purifier according to an embodiment of the present invention;
fig. 3 is a schematic diagram of a second circuit of the water purifier according to the embodiment of the invention;
FIG. 4 is a flowchart of a method for determining whether a water purifier is powered down according to the magnitude of the sampling current of the main control chip according to an embodiment of the present invention;
FIG. 5 is a flowchart of a method for determining whether a water purifier is powered down according to the magnitude of the sampling voltage of the main control chip according to an embodiment of the present invention;
fig. 6 is a schematic diagram of a third circuit of the water purifier according to the embodiment of the invention;
FIG. 7 shows an example of the power failure I of the water purifierDAnd/or UBChange, and VCC change profile;
fig. 8 is a schematic diagram of a fourth circuit of the water purifier according to the embodiment of the invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that the embodiments and features of the embodiments in the present application may be arbitrarily combined with each other without conflict.
The steps illustrated in the flow charts of the figures may be performed in a computer system such as a set of computer-executable instructions. Also, while a logical order is shown in the flow diagrams, in some cases, the steps shown or described may be performed in an order different than here.
Example one
A method for detecting power failure of a water purifier, as shown in fig. 1, the water purifier includes: the system comprises a system power supply 1, a load 2, a first resistor 3, a second resistor 4, a voltage stabilizing diode 5 and a main control chip 6; the main control chip 6 is used for sampling load current or load voltage; the system power supply 1, the load 2 and the first resistor 3 are sequentially connected in series and then grounded; the voltage stabilizing diode 5 is connected between the sampling end of the main control chip 6 and the ground in parallel; one end of the second resistor 4 is connected with the sampling end of the main control chip 6, and the other end is connected between the load 2 and the first resistor 3; as shown in fig. 2, the method for detecting the power failure of the water purifier includes the steps of S101:
s101, judging whether the water purifier is powered off or not according to the magnitude of the sampling current or the magnitude of the sampling voltage of the main control chip.
In the embodiment of the present invention, the system power supply 1 (VDD) is the working voltage of the load 2, the working power supply of the main control chip 6 is VCC, and VDD > VCC. The load 2 may be an inductive load, including a valve, a pump, etc. The first resistor 3 is used for boosting the voltage at the point A when the load 2 works, and the first resistor 3 can be selected to be added or not according to the load condition. The second resistor 4 is a current limiting resistor and can be used for protecting the zener diode 5.
Alternatively, as shown in fig. 3, the water purifier may further include: the device comprises a first switch 7, a second switch 8, a freewheeling diode 9, a first energy storage capacitor 10 and a filter capacitor 11;
wherein, the first switch 7 is connected in series between the load 2 and the first resistor 3;
the other end of the second resistor 4 is connected between the load 2 and the first switch 7;
the second switch 8 is connected in series between the system power supply 1 and the load 2;
the freewheeling diode 9 is connected in parallel with the load 2;
the first energy storage capacitor 10 and the filter capacitor 11 are connected in parallel between the sampling end of the main control chip 6 and the ground.
In the embodiment of the present invention, the first switch 7 may include a relay, a Mos transistor, a thyristor, and the like, and is mainly used for controlling the on/off of the load 2. The second switch 8 may also include a relay, a Mos transistor, a thyristor, etc. for controlling the on/off of the system power supply 1, and mainly plays a role in protection. The first switch 7 and the second switch 8 can be opened or closed under the control of the main control chip 6. The freewheeling diode 9 is used to provide a freewheeling path for the load 2 when the first switch 7 and/or the second switch 8 are turned on, so as to protect the load. The first energy storage capacitor 10 and the filter capacitor 11 are used for collecting the voltage U collected by the sampling end of the main control chip 6BAnd rectifying and filtering.
In the embodiment of the invention, when the water purifier works, if the power is off, the load current IDCan be reduced to 0 in a short time, and the sampling end of the main control chip 6 can collect the load current I in real timeDTherefore, whether the power is cut off during the working period of the water purifier is judged according to the magnitude of the sampling current. When the water purifier is not in operation, the load current IDAnd when the voltage is zero but the load voltage is not zero, the sampling end of the main control chip 6 can collect the load voltage in real time, and whether the power failure occurs during the non-working period of the water purifier is judged according to the magnitude of the sampling voltage. Generally, in the water purifier, the load may be an inductive load, including but not limited to a booster pump, a solenoid valve, and the like. According to the scheme of the embodiment, the current and the voltage of the load can be detected on the basis that the internal resistances of the switching tube and the load wire are basically certain, so that whether the periphery is powered off or not is judged.
Example two
The embodiment provides a specific embodiment for judging whether the water purifier is powered off or not through the size of the sampling current of the main control chip on the basis of the first embodiment.
Optionally, as shown in fig. 4, determining whether the water purifier is powered down according to the magnitude of the sampling current of the main control chip 6 may include S201 to S203:
s201, sampling a load current when the water purifier works, and comparing a first sampled current with a reference current which is measured in advance;
s202, when the first sampling current is larger than or equal to the reference current, judging that the water purifier is not powered off;
s203, when the first sampling current is smaller than the reference current, resampling the load current within a preset first time period, and comparing a second sampling current obtained by sampling with a preset current threshold; when the second sampling current is smaller than or equal to the current threshold, determining that the water purifier is powered off; and when the second sampling current is larger than the current threshold, resampling the load current, comparing the sampling current with the reference current and the current threshold again, and judging the power failure again.
In the embodiment of the invention, when the water purifier works normally and is not powered down, the current on the load 2 is kept stable, and the voltage U at the point A is kept stableA=ID*(RDS+R1+RN) In which IDIs the load current, RDSIs the internal resistance, R, of the first switch 7NThe wire resistance of the wire harness between the point A and the ground; rDS、R1、RNIs substantially fixed, that is to say UASubstantially by load current IDDetermination of size ID=UA/(RDS+R1+RN). According to the principle, the load current I can be obtained by detecting the voltage at the point A when the water purifier works normallyDAnd the load current I can be adjustedDAs a reference current.
In the embodiment of the invention, as can be seen from the above, if the load current is reduced to 0 in a short time when the water purifier is powered off during operation, the load current can be detected in real time according to the principle, and the load current and the reference current I can be comparedDA comparison is made to determine if the machine is powered down. If the comparison result shows that the load current is not reduced, the machine can be determined not to be powered down; if the comparison result shows that the load current is actually reduced, the reduced rate needs to be further judged to judge whether the machine is actually powered down, so as to avoid misjudgment caused by load current fluctuation. The specific scheme is that the load current is resampled within a preset first time period and is subjected to the samplingAnd comparing the sampled second sampled current with a preset current threshold value, wherein the current threshold value is a current value smaller than the reference current so as to judge whether the load current is actually reduced after a certain time delay. If the second sampling current is smaller than or equal to the current threshold, the magnitude of the load current is rapidly reduced to a lower value, and the water purifier can be judged to be powered off; when the second sampling current is larger than the current threshold, it is indicated that the magnitude of the load current is not rapidly reduced, and therefore, the current load current is smaller than the reference current, which may be caused by current fluctuation, the load current needs to be resampled, the sampling current is compared with the reference current and the current threshold again, and power failure judgment is performed again.
In the embodiment of the invention, the load current obtained by sampling is compared with the reference current and the current threshold value, so that the judgment accuracy is improved, the phenomenon of misjudgment caused by current fluctuation is prevented, and the method is simple, easy to understand and implement, and accurate and reliable in judgment result.
Optionally, the first duration may include: 4-7 seconds.
In the embodiment of the invention, the time range does not cause that the current cannot be timely reduced to the preset current threshold value after power failure because of too short time, and data loss or abnormal machine work caused by that the current cannot be timely reflected after power failure because of too long time can be avoided, and the time range is reasonable to set, so that the detection accuracy is ensured.
Optionally, the current threshold may include: k times the reference current, wherein k is more than 0 and less than 1.
In the embodiment of the invention, the current threshold is convenient to calculate and easy to implement.
EXAMPLE III
This embodiment further defines the current sampling method on the basis of the second embodiment.
Alternatively, the reference current is obtained by averaging the load current by sampling a plurality of times, and the reference current is updated by a moving average filtering method.
In the embodiment of the invention, the water purifier works normallyThe current can be continuously sampled for N times, and the current sampled for N times is averaged to be used as the reference current IDDue to the current I at the sampling end B point of the main control chip 6BI.e. the sampling current, then ID=IB=(I1+I2+…+In) Wherein, I1～InRespectively, N times of sampling current. According to the scheme of the embodiment, the accuracy of the sampling current can be checked, and large errors caused by single sampling are avoided.
In the embodiment of the present invention, the reference current may also be updated by a moving average filtering method. The moving average filtering method is as follows: the N sampling values are regarded as a queue, the length of the queue is N, the sampling value is placed at the tail of the queue every time sampling is carried out, and a sampling value at the head of the original queue is removed, so that N 'latest' sampling values are always in the queue, and the N values are averaged to obtain new reference current. The scheme of the embodiment further ensures the accuracy and reliability of the sampling current and further ensures the power failure detection precision.
Optionally, the sampling interval period t may satisfy t ≧ 0.5ms, and the sampling number N may satisfy N ≧ 10.
In the embodiment of the present invention, the sampling interval period t and the sampling times N may be defined by themselves according to different application scenarios, and specific values thereof are not limited.
Example four
The embodiment provides a specific embodiment for judging whether the water purifier is powered off or not through the size of the sampling current of the main control chip on the basis of the first embodiment.
Optionally, as shown in fig. 5, determining whether the water purifier is powered down according to the magnitude of the sampling voltage of the main control chip 6 may include S301 to S303:
s301, when the water purifier does not work, sampling the load voltage, and comparing the calculated first sampling voltage with a pre-stored reference voltage;
s302, when the first sampling voltage is equal to the reference voltage, judging that the water purifier is not powered down;
s303, when the first sampling voltage is smaller than the reference voltage, resampling the load voltage within a preset second time period, and comparing a second sampling voltage obtained by sampling with a preset voltage threshold value; and when the second sampling voltage is less than or equal to the voltage threshold, determining that the water purifier is powered down.
In the embodiment of the invention, when the water purifier does not work and is not powered down, the sampling voltage of the main control chip 6, namely the voltage U of the point BBRemain stable and UB=UwWherein U iswIs the regulated voltage across the zener diode 5. According to the principle, the voltage U can be obtained when the water purifier does not work and is not powered downwAs a reference voltage for detecting whether power is lost.
In the embodiment of the invention, if the power failure happens when the water purifier does not work, the voltage U at the point B isBWill be driven by U in a short timewDecreasing to 0. According to the principle, the voltage U at the point B can be sampled in real time when the water purifier does not workBAnd the sampling voltage is compared with the reference voltage UwA comparison is made to determine if the machine is powered down. If the comparison result is that the magnitude of the sampling voltage (namely the first sampling voltage) is not reduced and is equal to the reference voltage, the machine can be determined not to be powered down; if the comparison result is that the sampling voltage is actually reduced, the reduced rate needs to be further judged to judge whether the machine is actually powered down, so as to avoid misjudgment caused by detection errors. The specific scheme is that the load voltage is resampled within a preset second time length, and a second sampled voltage obtained by sampling is compared with a preset voltage threshold, wherein the voltage threshold is a voltage value smaller than a reference voltage, so that whether the sampled voltage is really reduced after a certain time delay is judged. If the second sampling voltage is smaller than or equal to the voltage threshold, the magnitude of the sampling voltage is rapidly reduced to a lower value, and the water purifier can be judged to be powered off.
In the embodiment of the invention, the sampling voltage obtained by sampling is compared with the reference voltage and the voltage threshold value, so that the judgment accuracy is improved, the phenomenon of misjudgment caused by detection errors is prevented, and the scheme is simple, easy to understand and implement, and accurate and reliable in judgment result.
Alternatively, the reference voltage may include: the voltage of a voltage stabilizing diode 5 is arranged at the sampling end of the main control chip 6;
the voltage threshold may include: n times of the reference voltage, wherein n is more than 0 and less than 1;
the second duration may include: 4-7 seconds.
EXAMPLE five
This embodiment further defines the power input circuit of the main control chip 6 on the basis of any of the above embodiments.
Alternatively, as shown in fig. 6, the water purifier may further include: the voltage stabilizing circuit 12, the second energy storage capacitor 13 and the third energy storage capacitor 14;
the power input end of the voltage stabilizing circuit 12 is connected with the system power supply 1; the power output end of the voltage stabilizing circuit 12 is connected with the power input end of the main control chip 6;
the anode of the second energy storage capacitor 13 is connected between the system power supply 1 and the voltage stabilizing circuit 12, and the cathode is grounded;
the anode of the third energy-storage capacitor 14 is connected between the voltage stabilizing circuit 12 and the power input end of the main control chip 6, and the cathode is grounded.
In the embodiment of the present invention, the power input terminal Vin of the voltage regulator 12 may be the system power supply 1 (VDD), or may be other power supplies, which is not limited herein.
Optionally, the sum of the capacitance values of the second energy storage capacitor 13 and the third energy storage capacitor 14 is greater than 10 uf.
In the embodiment of the invention, power failure is guaranteed and IDAnd UBWhen the VCC is changed and the state before power failure is maintained, the sum of the capacitance values of the second energy-storing capacitor 13 and the third energy-storing capacitor 14 can be kept>10 uf. As shown in FIG. 7, the external power is turned off at time T1, and at time I of T2DThe power supply VCC of the main control chip 6 starts to fall at T3 moment, and T3>T2, △ T = T3-T2, the presence of the second energy storage capacitor 13 and the third energy storage capacitor 14 being mainly guaranteed at △ T>1ms, when the power failure determination is completed, the VCC maintains the state before the power failure. If the second energy storage capacitor 13 and the third energy storage capacitor 14 are not present, T3 is less than or equal to T2, VCC power-down occurs at IDBefore descending, power failure judgment is not performedAnd (4) success.
EXAMPLE six
This embodiment further defines the power input circuit of the main control chip 6 on the basis of the fifth embodiment.
Alternatively, as shown in fig. 8, the water purifier may further include: an anti-reflux diode 15;
the anode of the anti-reflux diode 15 is connected with the system power supply 1; the cathode of the anti-reflux diode 15 is connected with the power input end of the voltage stabilizing circuit 12; or,
the anode of the anti-reflux diode 15 is connected with the power output end of the voltage stabilizing circuit 12; the cathode of the anti-reflux diode 15 is connected with the power supply input end of the main control chip 6.
In the embodiment of the present invention, the reverse flow prevention diode 15 may be disposed at the front stage of the second energy storage capacitor 13 or the front stage of the third energy storage capacitor 14, and the characteristic of unidirectional conduction of the reverse flow prevention diode 15 is utilized, so that the energy stored in the second energy storage capacitor 13 and the third energy storage capacitor 14 is not consumed by other loads, and the VCC retention time is longer when the power is down.
In the embodiment of the invention, due to the existence of the junction voltage of the anti-reflux diode 15, the position of the anti-reflux diode 15 is optimal before the second energy storage capacitor 13, and the anti-reflux diode has no influence on VCC; as shown in fig. 8.
In the embodiment of the invention, the scheme of the embodiment can store data in time after detecting the power failure, and can read the stored data again after the water purifier is powered on again, and the water purifier continues to work according to the working state of the machine last time.
The embodiment of the invention has the beneficial effects that:
1. the water purifier of the embodiment of the invention comprises: the system comprises a system power supply, a load, a first resistor, a second resistor, a voltage stabilizing diode and a main control chip; the main control chip is used for sampling load current or load voltage; the system power supply, the load and the first resistor are sequentially connected in series and then grounded; the voltage stabilizing diode is connected between the sampling end of the main control chip and the ground in parallel; one end of the second resistor is connected with the sampling end of the main control chip, and the other end of the second resistor is connected between the load and the first resistor; the power failure detection method of the water purifier comprises the following steps: and judging whether the water purifier is powered off or not according to the magnitude of the sampling current or the magnitude of the sampling voltage of the main control chip. According to the scheme of the embodiment of the invention, the power failure condition of the water purifier can be detected in time, so that data loss and abnormal work of a machine are avoided.
2. The embodiment of the invention judges whether the water purifier is powered off or not according to the sampling current of the main control chip, and comprises the following steps: when the water purifier works, sampling load current, and comparing the collected first sampling current with a reference current measured in advance; when the first sampling current is larger than or equal to the reference current, judging that the water purifier is not powered off; when the first sampling current is smaller than the reference current, resampling the load current within a preset first time period, and comparing a second sampling current obtained by sampling with a preset current threshold; when the second sampling current is smaller than or equal to the current threshold, determining that the water purifier is powered off; and when the second sampling current is larger than the current threshold, resampling the load current, comparing the sampling current with the reference current and the current threshold again, and judging the power failure again. According to the embodiment, the load current obtained by sampling is compared with the reference current, and the power failure condition is judged according to the comparison result, so that the method is simple, easy to understand, easy to implement, accurate and reliable.
3. In the embodiment of the invention, the reference current is obtained by sampling and averaging the load current for multiple times, and the reference current is updated by adopting a moving average filtering method. The embodiment of the scheme ensures the accuracy and reliability of the load current and further ensures the power failure detection precision.
4. The first time period in the embodiment of the invention comprises the following steps: 4-7 seconds, the time range can not cause the current after the power failure to timely drop to the preset current threshold value because of too short time, and can not cause data loss or abnormal machine work because of not timely reflecting after the power failure because of too long time, and the time range is reasonable to set, thereby ensuring the detection accuracy.
5. In the embodiment of the invention, the sum of the capacitance values of the second energy storage capacitor and the third energy storage capacitor is more than 10 uf. According to the scheme of the embodiment, when the machine is powered down, the sampling current and the sampling voltage of the sampling end of the main control chip are changed, and the input power VCC of the main control chip maintains the state before the power down.
Although the embodiments of the present invention have been described above, the above description is only for the convenience of understanding the present invention, and is not intended to limit the present invention. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.
Claims (10)
1. A power failure detection method for a water purifier is characterized in that the water purifier comprises the following steps: the system comprises a system power supply, a load, a first resistor, a second resistor, a voltage stabilizing diode and a main control chip; the main control chip is used for sampling the load current or the load voltage; the system power supply, the load and the first resistor are sequentially connected in series and then grounded; the voltage stabilizing diode is connected between the sampling end of the main control chip and the ground in parallel; one end of the second resistor is connected with the sampling end of the main control chip, and the other end of the second resistor is connected between the load and the first resistor; the power failure detection method of the water purifier comprises the following steps:
judging whether the water purifier is powered off or not according to the magnitude of the sampling current or the magnitude of the sampling voltage of the main control chip;
when the water purifier works, the sampling current is obtained, and whether the power is off or not in the working period of the water purifier is judged according to the magnitude of the sampling current; and when the water purifier does not work, acquiring the sampling voltage, and judging whether the power is down or not during the non-working period of the water purifier according to the size of the sampling voltage.
2. The method for detecting the power failure of the water purifier according to claim 1, wherein the step of judging whether the water purifier has the power failure or not according to the magnitude of the sampling current of the main control chip comprises the following steps:
when the water purifier works, sampling the load current, and comparing the collected first sampling current with a reference current measured in advance;
when the first sampling current is larger than or equal to the reference current, judging that the water purifier is not powered down;
when the first sampling current is smaller than the reference current, resampling the load current within a preset first time period, and comparing a second sampling current obtained by sampling with a preset current threshold; when the second sampling current is smaller than or equal to the current threshold, determining that the water purifier is powered down; and when the second sampling current is larger than the current threshold, resampling the load current, comparing the sampling current with the reference current and the current threshold again, and judging the power failure again.
3. The method for detecting the power failure of the water purifier according to claim 2, wherein the reference current is obtained by averaging the load current by sampling for a plurality of times, and the reference current is updated by a moving average filtering method.
4. The method for detecting the power failure of a water purifier according to claim 2,
the first time period includes: 4-7 seconds;
the current threshold includes: k times of the reference current, wherein k is more than 0 and less than 1.
5. The method for detecting the power failure of the water purifier according to claim 1, wherein the step of judging whether the water purifier has the power failure or not according to the magnitude of the sampling voltage of the main control chip comprises the following steps:
when the water purifier does not work, sampling the load voltage, and comparing the calculated first sampling voltage with a prestored reference voltage;
when the first sampling voltage is equal to the reference voltage, judging that the water purifier is not powered down;
when the first sampling voltage is smaller than the reference voltage, resampling the load voltage within a preset second time period, and comparing a second sampling voltage obtained by sampling with a preset voltage threshold value; and when the second sampling voltage is less than or equal to the voltage threshold, determining that the water purifier is powered down.
6. The water purifier power failure detection method according to claim 5,
the reference voltage includes: the voltage of a voltage stabilizing diode is arranged at the sampling end of the main control chip;
the voltage threshold includes: n times of the reference voltage, wherein n is more than 0 and less than 1;
the second duration comprises: 4-7 seconds.
7. The method for detecting the power failure of the water purifier according to claim 1, wherein the water purifier further comprises: the device comprises a first switch, a second switch, a freewheeling diode, a first energy storage capacitor and a filter capacitor;
wherein the first switch is connected in series between the load and the first resistor;
the other end of the second resistor is connected between the load and the first switch;
the second switch is connected in series between the system power supply and the load;
the freewheeling diode is connected to the load in parallel;
the first energy storage capacitor and the filter capacitor are connected between the sampling end of the main control chip and the ground in parallel.
8. The method for detecting the power failure of the water purifier according to claim 1, wherein the water purifier further comprises: the voltage stabilizing circuit, the second energy storage capacitor and the third energy storage capacitor;
the power supply input end of the voltage stabilizing circuit is connected with the system power supply; the power supply output end of the voltage stabilizing circuit is connected with the power supply input end of the main control chip;
the anode of the second energy storage capacitor is connected between the system power supply and the voltage stabilizing circuit, and the cathode of the second energy storage capacitor is grounded;
and the anode of the third energy storage capacitor is connected between the voltage stabilizing circuit and the power input end of the main control chip, and the cathode of the third energy storage capacitor is grounded.
9. The power-down detection method for the water purifier according to claim 8, wherein the sum of the capacitance values of the second energy storage capacitor and the third energy storage capacitor is greater than 10 uf.
10. The method for detecting the power failure of the water purifier according to claim 8, wherein the water purifier further comprises: an anti-reflux diode;
the anode of the anti-reflux diode is connected with the system power supply; the cathode of the anti-reflux diode is connected with the power input end of the voltage stabilizing circuit; or,
the anode of the anti-reflux diode is connected with the power output end of the voltage stabilizing circuit; and the cathode of the anti-reflux diode is connected with the power supply input end of the main control chip.
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| CN108646112A (en) * | 2018-05-17 | 2018-10-12 | 湖南汉拓物联科技有限公司 | A kind of monitoring device and monitoring system of purifier |
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