CN103245398B - Method and system for detecting water level of electromagnetic water boiler - Google Patents
Method and system for detecting water level of electromagnetic water boiler Download PDFInfo
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- CN103245398B CN103245398B CN201310141457.XA CN201310141457A CN103245398B CN 103245398 B CN103245398 B CN 103245398B CN 201310141457 A CN201310141457 A CN 201310141457A CN 103245398 B CN103245398 B CN 103245398B
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Abstract
An embodiment of the invention discloses a method for detecting the water level of an electromagnetic water boiler. The method specifically includes the steps: obtaining audio signals of the process when the electromagnetic water boiler operates, performing amplification processing to the audio signals, filtering to obtain an envelope line of sound intensity changes, performing A/D (analog to digital) conversion through a microprocessor to remove interference signals to obtain an audio envelope curve, monitoring the audio envelope curve in real time, calculating a time span value when reaching the maximum sound intensity value by heating, adopting a least square method to linearly fit the audio envelope curve, and calculating starting temperature when the electromagnetic water boiler operates; and establishing a mathematic model formula of size according to the time span value and the starting temperature, and calculating the water level. The embodiment of the invention further discloses a system for detecting the water level of the electromagnetic water boiler. By adopting the method and the system for detecting the water level of the electromagnetic water boiler, any detecting device is avoided being arranged in a kettle, and detection is realized through sound collection and operation processing by the microprocessor, so that defects of disadvantages and unsafety caused by the fact that power supply is needed in the prior art are overcome.
Description
Technical field
The present invention relates to a kind of level testing methods and system, particularly relate to a kind of level testing methods and the system that are applicable to electromagnetism equipment to boil water.
Background technology
At present along with progress and people's growth in the living standard of science and technology, especially electromagnetic equipment application is in daily life more and more extensive for small household appliances, as electromagnetism calorifier, coffee machine, water dispenser etc., and in these equipment to boil water, generally all need condensate tank of dehumidifier, be beneficial to realize various function, and in the prior art at present, the power supply mode of small household appliances generally adopts resistance-capacitance depressurization to power, and adopt resistance-capacitance depressurization to power to rear class less than isolation, and when rear class is not isolated, if direct-detection water level knows from experience generation danger of hazardous electrical discharges to people.
Summary of the invention
Embodiment of the present invention technical matters to be solved is, provides a kind of electromagnetism calorifier level testing methods and system.The water level detecting of noncontact, water power isolation can be realized.
In order to solve the problems of the technologies described above, embodiments provide a kind of electromagnetism calorifier level testing methods, concrete steps are as follows:
Obtain the sound signal of the described electromagnetism calorifier course of work, described sound signal is amplified process through signal amplification circuit, extracted the envelope of the sound intensity change of described sound signal by signal filter circuit;
To comprise the signal input microprocessor of the envelope of described sound intensity change, described sound intensity variable signal is carried out A/D conversion by described microprocessor, and filters undesired signal, obtains audio frequency enveloping curve;
Monitor the sound intensity maximal value of described audio frequency enveloping curve, calculate the time span value that described electromagnetism calorifier is heated to described sound intensity maximal value;
Use and adopt least square method to do audio frequency enveloping curve described in fitting a straight line, calculate the initial temperature of described electromagnetism calorifier work;
Set up the mathematical model formula of volume according to described time span value and described initial temperature, draw corresponding water level.
Further, the initial temperature calculating the work of described electromagnetism calorifier is calculated by function T=K* θ+C, and wherein θ is the angle of fitting a straight line and x-axis, and K is temperature coefficient, and C is temperature drift constant.
Further, the described mathematical model formula setting up volume is
, wherein △ t is described time span value, and T is initial temperature, and a is correction coefficient, and M is scale-up factor.
Correspondingly, the embodiment of the present invention additionally provides a kind of electromagnetism calorifier water level detecting system, comprises pickup unit, signal amplification unit, signal filtering unit, microprocessor module;
Described pickup unit is for obtaining the sound signal of the electromagnetism calorifier course of work;
Described sound signal is carried out amplification process by described signal amplification unit;
Described signal filtering unit is for extracting the envelope of the sound intensity change of described sound signal;
Described microprocessor module comprises A/D converting unit, goes interference units, arithmetic element, the signal of the envelope comprising the change of the described sound intensity carries out being quantized into digital signal by described A/D converting unit, and goes interference units to remove undesired signal composition acquisition audio frequency enveloping curve described in warp; Monitor the maximal value of the sound intensity of described audio frequency envelope signal, calculate the time span value that described electromagnetism calorifier is heated to described maximal value, use and adopt least square method to do audio frequency enveloping curve described in fitting a straight line, calculate the initial temperature of described electromagnetism calorifier work; Described arithmetic element sets up the mathematical model formula of volume according to described time span value and described initial temperature, draws corresponding water level.
Further, described in calculate the work of described electromagnetism calorifier initial temperature be calculated by function T=K* θ+C, wherein θ is the angle of fitting a straight line and x-axis, and K is temperature coefficient, and C is temperature drift constant.
Further, the described mathematical model formula setting up volume is
, wherein △ t is described time span value, and T is initial temperature, and a is correction coefficient, and M is scale-up factor.
Implement the embodiment of the present invention, there is following beneficial effect: the present invention utilizes water at the peculiar sound variation curve through electromagnetic equipment heating process, the sound intensity change audio frequency of process of being heated up water by acoustic pickup collection, A/D conversion is carried out by microprocessor after amplifying process and filtering, gaussian curve approximation is utilized to set up sound intensity enveloping curve, and the volume that the mathematical model formulae discovery setting up volume goes out heated water draws water level, present invention, avoiding and any pick-up unit is set in kettle, and detecting is undertaken by sound collection and microprocessor calculation process, overcome needs of the prior art power supply etc. unfavorable, dangerous defect.
Accompanying drawing explanation
Fig. 1 is the schematic diagram of the audio frequency enveloping curve that the present invention obtains;
Fig. 2 is the audio frequency envelope curve synoptic diagram of two providing Fig. 1 water yield;
Fig. 3 to be the temperature initial value provided when heating water be audio frequency envelope curve synoptic diagram of 80 DEG C;
Fig. 4 is the structural representation of present system.
Embodiment
For making the object, technical solutions and advantages of the present invention clearly, below in conjunction with accompanying drawing, the present invention is described in further detail.
The invention process provides a kind of electromagnetism calorifier level testing methods, according to the Changing Pattern of electromagnetism calorifier at the sound of the process of heating up water,
Electromagnetism calorifier arranges sound transducer, obtains the sound signal of electromagnetism calorifier in the process of heating up water, by sound signal amplifying circuit, amplification process is carried out, so that be for further processing to sound signal; Sound signal after amplifying is passed through filtering circuit, reject high-frequency components, extract the envelope of sound signal, by comprising the signal input microprocessor of the envelope of sound intensity change, by the A/D converter of microprocessor, sound signal is quantized to adopt integrated Digital Signal, the routine processes of leading to microprocessor built-in falls undesired signal composition, obtains audio frequency enveloping curve, schematic diagram as shown in Figure 1, ordinate represents the sound intensity, and horizontal ordinate is expressed as the time.
Wherein, Signal averaging when sound intensity signal is heated by the background sound and water during electric heating equipment work forms, and the described background sound is fan noise, vibration pot sound, outside noise etc.During equipment heating to boil water, the sound intensity can change by generating period, voice signal when equipment to boil water heats is obtained by sound transducer, filtering interfering composition, and this signal is amplified, then signal after filtering circuit extraction go out the envelope of the sound intensity, find out mathematical model by gaussian curve approximation, and set up coordinate system.
When the water yield increases, audio frequency enveloping curve is also along with doing corresponding change, and Fig. 2 shows when the water yield is the twice of Fig. 1 heating water to change curve schematic diagram during boiling.
And the initial temperature working as heated water is when being 80 DEG C, the change curve represented by it as shown in Figure 3.
Audio frequency envelope curve synoptic diagram according to Fig. 1, Fig. 2, Fig. 3, the variation tendency of water sound intensity when electromagnetism calorifier heats is fallen after rising, and finally tends towards stability.As seen from the figure, among latter half t2 to the t3 time period, sound intensity change similarity-rough set is high, show that the sound intensity change of different water level is not high at this interval may differentiate, does not analyze thus.
The embodiment of the present invention selects the curve heating water to this one-phase of sound intensity maximal value to detect foundation for doing, and improves the accuracy rate detected, i.e. t1 ~ t2 stage.
The maximal value that Real-Time Monitoring audio frequency enveloping curve occurs, calculate the time span value that electromagnetism calorifier is heated to described sound intensity maximal value, and by program, least square method is done to audio frequency enveloping curve and do fitting a straight line, the straight line obtained by matching, obtain the angle of straight line and x-axis, obtain characteristic angle θ, calculated the initial temperature of process of heating up water by function T=K* θ+C, wherein K is temperature coefficient, and C is temperature drift constant.
The mathematical model formula setting up volume according to time span value and described initial temperature is
, wherein △ t is described time span value, and T is initial temperature, and a is correction coefficient, and M is scale-up factor, calculates the ratio value of the volume V of institute's heating water, namely draws its water level conditions.
To be described by a specific embodiment below.
In this enforcement, by microprocessor A/D conversion is carried out to the signal of the envelope that the sound intensity changes and after removing undesired signal, obtain audio frequency enveloping curve, by least square method, matching is carried out to obtained audio frequency enveloping curve, the straight line of real-time calculating institute matching audio frequency enveloping curve and the angle of x-axis, to draw the computing function of the beginning temperature value of heating, show that data are as shown in table 1.
Table 1
According to the matched curve of least square method, the function obtaining the initial temperature of electromagnetism calorifier work is T=0.92* θ+8.3, certainly the corresponding different temperature coefficient (K) of different devices and temperature drift constant (C), it is determined according to physical device, and the embodiment of the present invention is not limited thereto.
The maximal value that real-time detection audio frequency enveloping curve occurs, calculating the time span value △ t(unit that electromagnetism calorifier starts to be heated to described sound intensity maximal value is second), and initial temperature, the mathematical model formula set up about vertical volume ratio is
, △ t: time span (t2-t1) (second is unit), T: initial temperature, α: correction coefficient, M is scale-up factor, and the mode below by way of experiment draws the parameter value of formula, data as shown in table 2.
The test process of the present embodiment is as follows:
1. first set water yield ratio (from 0.1) in kettle, reset initial water temperature (from 10 degree).
2. each water yield position, sets nine kinds of initial temperatures (10-90 degree).
3. the time span △ t that test water is boiled.
Each same parameter experiment repetition 10 times, △ t value is the mean value of 10 times.
Table 2
Obtained by the linear fit of ln function
, be 1000 in this scale-up factor M value.
The embodiment of the present invention gives a kind of electromagnetism calorifier water level detecting system, comprises pickup unit 10, signal amplification unit 20, signal filtering unit 30, microprocessor module 40.
Pickup unit 10 is the sound transducers being arranged at electromagnetism calorifier, such as Electret Condencer Microphone, but the embodiment of the present invention is not limited thereto, it is for obtaining sound signal during equipment to boil water heating, and carry out amplification process by signal amplification unit 20, signal filtering unit 30 be by amplify after signal carry out filtering high-frequency components, and obtain the sound intensity change envelope.
Microprocessor module 40 contains A/D converting unit 401, goes interference units 402, arithmetic element 403, A/D converting unit 401 carries out sampling and quantizing for the signal of the envelope changed by the sound intensity, collects and records the unique point of the envelope of the sound intensity change procedure of the process of heating up water.
Go interference units 402 to be removed by the interference tones composition of electromagnetism calorifier by program, interference tones composition contains fan noise, vibration pot sound, outside noise etc., these compositions is removed the real-time operation process to enter next step.
There is the maximal value of the sound intensity in arithmetic element 403 Real-Time Monitoring audio frequency enveloping curve, calculate the time span value △ t that electromagnetism calorifier is heated to described maximal value, and adopt least square method to do audio frequency enveloping curve described in fitting a straight line, the initial temperature started when heating is calculated by function T=K* θ+C, wherein θ is the angle of fitting a straight line and x-axis, K is temperature coefficient, and C is temperature drift constant, and parameter K and C is for press equipment factory setting.
Arithmetic element 403 also sets up the mathematical model formula of volume according to described time span value and described initial temperature
, draw corresponding water level ratio, △ t is described time span value, and T is initial temperature, and a is correction coefficient, and M is scale-up factor, and a is factory setting value, and M determines according to physical device, becomes water level detecting completely thus.
Method and system of the present invention processes to obtain detection calculations by single-chip microcomputer to voice signal, mathematical model according to setting up draws water level, overcome in prior art the defect needing to power and need more sensor, detected water level more easily, can be applied in multiple environment for use, such as preventing dry combustion etc.
The above is the preferred embodiment of the present invention; it should be pointed out that for those skilled in the art, under the premise without departing from the principles of the invention; can also make some improvements and modifications, these improvements and modifications are also considered as protection scope of the present invention.
Claims (4)
1. an electromagnetism calorifier level testing methods, is characterized in that, concrete steps are as follows:
Obtain the sound signal of the described electromagnetism calorifier course of work, described sound signal is amplified process through signal amplification circuit, extracted the envelope of the sound intensity change of described sound signal by signal filter circuit;
To comprise the signal input microprocessor of the envelope of described sound intensity change, described sound intensity variable signal is carried out A/D conversion by described microprocessor, and filters undesired signal, obtains audio frequency enveloping curve;
Monitor the sound intensity maximal value of described audio frequency enveloping curve, calculate the time span value that described electromagnetism calorifier is heated to described sound intensity maximal value;
Use and adopt least square method to do audio frequency enveloping curve described in fitting a straight line, calculate the initial temperature of described electromagnetism calorifier work;
The mathematical model formula of volume is set up according to described time span value and described initial temperature
, draw corresponding water level, wherein △ t is described time span value, and T is initial temperature, and α is correction coefficient, and M is scale-up factor.
2. electromagnetism calorifier level testing methods according to claim 1, it is characterized in that, the initial temperature calculating the work of described electromagnetism calorifier is calculated by function T=K* θ+C, and wherein θ is the angle of fitting a straight line and x-axis, K is temperature coefficient, and C is temperature drift constant.
3. an electromagnetism calorifier water level detecting system, is characterized in that, comprises pickup unit, signal amplification unit, signal filtering unit, microprocessor module;
Described pickup unit is for obtaining the sound signal of the electromagnetism calorifier course of work;
Described sound signal is carried out amplification process by described signal amplification unit;
Described signal filtering unit is for extracting the envelope of the sound intensity change of described sound signal;
Described microprocessor module comprises A/D converting unit, goes interference units, arithmetic element, the signal of the envelope comprising the change of the described sound intensity carries out being quantized into digital signal by described A/D converting unit, and goes interference units to remove undesired signal composition acquisition audio frequency enveloping curve described in warp; Monitor the maximal value of the sound intensity of described audio frequency envelope signal, calculate the time span value that described electromagnetism calorifier is heated to described maximal value, use and adopt least square method to do audio frequency enveloping curve described in fitting a straight line, calculate the initial temperature of described electromagnetism calorifier work; Described arithmetic element sets up the mathematical model formula of volume according to described time span value and described initial temperature
, draw corresponding water level, wherein △ t is described time span value, and T is initial temperature, and α is correction coefficient, and M is scale-up factor.
4. electromagnetism calorifier water level detecting system according to claim 3, it is characterized in that, described in calculate the work of described electromagnetism calorifier initial temperature be calculated by function T=K* θ+C, wherein θ is the angle of fitting a straight line and x-axis, K is temperature coefficient, and C is temperature drift constant.
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| CN201310141457.XA CN103245398B (en) | 2013-04-23 | 2013-04-23 | Method and system for detecting water level of electromagnetic water boiler |
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| CN201310141457.XA CN103245398B (en) | 2013-04-23 | 2013-04-23 | Method and system for detecting water level of electromagnetic water boiler |
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| CN107992808B (en) * | 2017-11-24 | 2019-01-11 | 朱健坤 | The feature extraction of acoustic signals time-frequency combination and boiling recognition methods of boiling vibrating |
| CN110313826A (en) * | 2018-03-28 | 2019-10-11 | 佛山市顺德区美的电热电器制造有限公司 | Liquid overflow detection method and device, cookware, electromagnetic heating component |
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| JPH02118320A (en) * | 1988-10-28 | 1990-05-02 | Matsushita Electric Ind Co Ltd | Broiler |
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| CN101900412A (en) * | 2009-05-27 | 2010-12-01 | 博西华电器（江苏）有限公司 | Water heater with water leakage detecting function |
| CN102518856A (en) * | 2011-12-31 | 2012-06-27 | 东南大学 | Water boiler energy-saving switch utilizing audio frequency to control switching on/off and method thereof |
| CN202418820U (en) * | 2011-12-31 | 2012-09-05 | 东南大学 | Water boiler water-saving switch capable of controlling opening and closing through audio |
| CN102999060A (en) * | 2012-05-13 | 2013-03-27 | 李祥龙 | Method and circuit for controlling automatic heating stop of water boiling induction cooker after boiling |
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2013
- 2013-04-23 CN CN201310141457.XA patent/CN103245398B/en not_active Expired - Fee Related
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02118320A (en) * | 1988-10-28 | 1990-05-02 | Matsushita Electric Ind Co Ltd | Broiler |
| WO2010046306A2 (en) * | 2008-10-22 | 2010-04-29 | BSH Bosch und Siemens Hausgeräte GmbH | Hot water tank, and method for the operation of a hot water tank |
| CN101900412A (en) * | 2009-05-27 | 2010-12-01 | 博西华电器（江苏）有限公司 | Water heater with water leakage detecting function |
| CN102518856A (en) * | 2011-12-31 | 2012-06-27 | 东南大学 | Water boiler energy-saving switch utilizing audio frequency to control switching on/off and method thereof |
| CN202418820U (en) * | 2011-12-31 | 2012-09-05 | 东南大学 | Water boiler water-saving switch capable of controlling opening and closing through audio |
| CN102999060A (en) * | 2012-05-13 | 2013-03-27 | 李祥龙 | Method and circuit for controlling automatic heating stop of water boiling induction cooker after boiling |
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Application publication date: 20130814 Assignee: Guangdong Xingong Electrical Appliances Co., Ltd. Assignor: Fu Yinrong Contract record no.: 2015440000720 Denomination of invention: Method and system for detecting water level of electromagnetic water boiler Granted publication date: 20150617 License type: Exclusive License Record date: 20151020 |
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