CN103713225A - Capacity discharge tester - Google Patents

Capacity discharge tester Download PDF

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Publication number
CN103713225A
CN103713225A CN201410009151.3A CN201410009151A CN103713225A CN 103713225 A CN103713225 A CN 103713225A CN 201410009151 A CN201410009151 A CN 201410009151A CN 103713225 A CN103713225 A CN 103713225A
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CN
China
Prior art keywords
circuit
voltage
discharge tester
direct current
capacitor discharge
Prior art date
Application number
CN201410009151.3A
Other languages
Chinese (zh)
Inventor
陈帆
张光辉
陈照
贾柯
鹿文军
Original Assignee
深圳出入境检验检疫局工业品检测技术中心
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Application filed by 深圳出入境检验检疫局工业品检测技术中心 filed Critical 深圳出入境检验检疫局工业品检测技术中心
Priority to CN201410009151.3A priority Critical patent/CN103713225A/en
Publication of CN103713225A publication Critical patent/CN103713225A/en

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Abstract

The invention provides a capacity discharge tester which is of a box structure. The capacity discharge tester comprises a power switch, a power circuit, an executing circuit, a control circuit, a sampling circuit and a man-machine interface, wherein the power circuit and the executing circuit are connected with the power switch, and one end of the sampling circuit and the man-machine interface are connected with the control circuit. According to the capacity discharge tester, a relay can be disconnected at the peak position accurately, and the output resistance is larger than 100 megohms so that different external devices can be detected. The invention further provides a testing method of the capacity discharge tester. The method comprises the steps of (1) recording the period and peak value of an external voltage connected with the external device to be detected, (2) conducting delay disconnection at the zero point, (3) recording the moment t1 when the discharging voltage reduces to be 37% of the peak value, (4) recording the moment t2 when the discharging voltage reduces to 60V, (5) recording discharging voltage values at different moments, and (6) ending detection and displaying the detection result.

Description

Capacitor discharge tester
Technical field
The present invention relates to a kind of electron detection device, relate in particular to a kind of universal capacitor discharge tester that meets multinomial standard.
Background technology
In product safety qualification testing and authentication, the capacitor discharge of input port is very important project, in all motor products, all will carry out this object experiment.The capacitor discharge that requires according to test must cut off input voltage at the peak value place of power supply, when cutting off voltage, also needs with oscillograph, to capture waveform, reading out data.There is like this problem of two aspects, the first, the conventional power supply that utilizes switch to control, is typically in the situation that voltage is 50Hz or 60Hz, and the interval of each peak value, between 16.7ms~20ms, is not easy to cut off input voltage when power supply peak value; The second, in actual operation, utilize oscillograph manual operation to capture the sparking voltage maximal value of moment more difficult, the error ratio of introducing is larger.
When capacitor discharge is tested, the input resistance of metering circuit has impact to the discharge measuring of testing apparatus, requirement to measuring equipment in safety standard GB4943.1-2011 is " input impedance 100 ± 5M Ω, input capacitance are at 25pF or less measuring equipment ", thereby just may reduce the impact of the internal resistance of measuring equipment on discharge time as far as possible.In order to meet such requirement, metering circuit must be equipped with the high-voltage probe of expensive high input impedance and low input capacitance, has improved the cost of measuring equipment and circuit.
In addition, for China's household appliances port discharge resistance and sparking voltage, add up, wherein discharge capacity is at 0.1~1 μ F, and discharge resistance is less than 500K, after can guaranteeing that like this attaching plug is pulled out, the safety limit of can within the extremely short time, residual voltage being released.
Summary of the invention
The technical problem to be solved in the present invention is: provide a kind of and automatically at voltage peak place deenergization, connect, record sparking voltage and time, and intuitively show, need not build in addition test platform, meet the general form capacitor discharge tester of a plurality of testing standards.
For achieving the above object, the invention provides a kind of capacitor discharge tester, there is body structure, comprising: the power switch that connects outside civil power; And the power circuit and the executive circuit that are connected with this power switch; Control circuit; The sample circuit one end and the man-machine interface that are connected with control circuit;
Described power circuit is connected with control circuit, and described executive circuit is connected with control circuit, and for connecting outside equipment under test, the described sample circuit other end is connected between executive circuit and outside equipment under test;
Described executive circuit comprises driving circuit and relay;
Described control circuit is 16 TMS320F2816 type dsp processors that comprise ADC Sampling Interface.
Described man-machine interface comprises keystroke interface, liquid crystal panel interface and the USB interface that connects control button.
The voltage of power circuit output be ± 12V direct current, 3.3V direct current and 1.9V direct current, and described ± 12V direct current is by dsp processor to relay and drive circuitry, and described+3.3V direct current is powered to dsp processor with+1.9V direct current.
Described sample circuit is differential amplifier, and its input impedance is greater than 100M Ω, and input capacitance is less than 25pF, is connected to the ADC Sampling Interface of DSP.
It is a kind of for accurately obtain the method for testing of the capacitor discharge tester of multi-group data in single step of releasing electric process simultaneously that the present invention also provides.
For achieving the above object, the method for testing of this capacitor discharge tester, comprises the following steps:
Step 1: determine and record outside equipment under test to connect external voltage cycle and peak value, judgement is direct current or interchange;
Step 2: the cycle of detecting step 1 record and peak value externally voltage are crossed theory time delay disconnection during zero point, make outside equipment under test be equivalent to externally voltage theoretical peak place and disconnect, and start timing simultaneously;
Step 3: detect and record outside equipment under test sparking voltage and electric discharge duration, record moment t when this sparking voltage is down to peak value 37% 1;
Step 4: record moment t when this sparking voltage is down to 60V 2;
Step 5: do not recording in the same time sparking voltage value respectively;
Step 6: detect and finish, show testing result.
In step 2, delay time is 1/4 of the external voltage cycle; The moment different in step 5 comprise t 1, 1s, 2s, 10s and 5min.
Beneficial effect of the present invention: capacitor discharge tester provided by the invention adopts relay and dsp processor as control section, adopt simultaneously and be connected to the supply voltage that the sample circuit of dsp processor can the outside equipment under test of high-precision sampling, when this supply voltage peak value, disconnect relay, and recording the sparking voltage of this outside equipment under test, its sampling precision is high can disconnect relay accurately at peak value place; It is owing to having adopted output resistance to be greater than the sample circuit of 100M Ω, can be for detection of the different outside equipment under test of test, can meet a plurality of different testing standards, comprise GB4706.1/GB4943.1/GB7260.1/GB9706.1/GB8898, its versatility is good; Reduced traditional measuring error of utilizing oscillograph observation judgement sparking voltage to cause because of manual operation inconvenience.
The method of testing of this capacitor discharge tester provided by the invention can first detect outside equipment under test external voltage, after power-off, can detect this sparking voltage drop to maximum input voltage peak value 37% or 60V time used for this sparking voltage; Can also detect externally equipment under test power-off afterwards respectively at t simultaneously 1, 1s, 2s, 10s and sparking voltage value in the 5min time.Particularly on the basis of the structure based on above-mentioned capacitor discharge tester, utilize dsp processor, relay and 12 sample circuits can determine accurately fast power-cut time, and can utilize dsp processor to carry out compensation of delay, obtain each magnitude of voltage accurately.
In order further to understand feature of the present invention and technology contents, refer to following about detailed description of the present invention and accompanying drawing, yet accompanying drawing only provide with reference to and explanation use, be not used for the present invention to be limited.
Accompanying drawing explanation
Below in conjunction with accompanying drawing, by the specific embodiment of the present invention is described in detail, will make technical scheme of the present invention and other beneficial effect apparent.
In accompanying drawing,
Fig. 1 is capacitor discharge tester circuit link block figure of the present invention;
Fig. 2 A and 2B are the circuit diagram that capacitor discharge tester power circuit 12V of the present invention becomes 3.3V and 1.9V;
Fig. 3 is capacitor discharge tester sample circuit schematic diagram of the present invention;
Fig. 4 is capacitor discharge tester method of testing schematic diagram of the present invention;
Fig. 5 is the schematic flow sheet of capacitor discharge tester method of testing of the present invention.
Accompanying drawing explanation:
1, power switch; 2, power circuit; 3, executive circuit; 31, relay; 32, driving circuit; 4, control circuit; 5, sample circuit; 6, man-machine interface; 7, outside equipment under test.
Embodiment
Technological means and the effect thereof for further setting forth the present invention, taked, be described in detail below in conjunction with the preferred embodiments of the present invention and accompanying drawing thereof.
Refer to Fig. 1, for achieving the above object, the invention provides a kind of capacitor discharge tester, there is body structure, comprising: connect the power switch 1 of outside civil power, it is outside that this power switch 1 is arranged on this casing.
Also comprise the power circuit 2 and the executive circuit 3 that are connected with this power switch 1; Control circuit 4; One end of the sample circuit 5 being connected with control circuit 4 and man-machine interface 6.
Described power circuit 2 is connected with control circuit 4, and described executive circuit 3 is connected with control circuit 4, and for connecting outside equipment under test 7, described sample circuit 5 other ends are connected between executive circuit 3 and outside equipment under test 7.
Described executive circuit 3 comprises driving circuit 32 and relay 31.
Described driving circuit 32 is for mating voltage between control circuit 4 and relay 31 and impedance, and controlled circuit 4 controls are closed or open relay 31, described relay 31 can be controlled according to the state of self break-make of the external power source of outside equipment under test 7.Relay 31 adopts the tandem compound of mechanical contact-type relay or electronics solid-state relay, wherein between two contacts of mechanical contact-type relay, keep 1.5mm, in order to guarantee the safety isolation between metering circuit and equipment under test circuit after power-off, electronics solid-state relay is used for guaranteeing that the moment that signal triggers cuts off circuit fast.
Described control circuit 4 is 16 TMS320F2816 type dsp processors that comprise ADC Sampling Interface.The dsp processor of this model has the ADC analog-converted interface of 12, has met the requirement of acquisition precision.It can guarantee at 5 pairs of equipment under test 7 external samplings of sample circuit and after passing to DSP, can judge the peak-peak of this external voltage.
Thereby dsp processor is by driving circuit 32 pilot relay 31 disconnecting external power supplys when obtaining peak-peak, and now outside equipment under test 7 will enter the discharge test stage, it is because relay 31 has high impedance, so discharge current can enter dsp processor through sample circuit 5.
Process is to the input capacitance of China's household appliances port and the statistics of input resistance, and its input capacitance is on one side at 0.1~1 μ F, and input resistance is in 500K Ω.We are the input circuit at 1 μ F according to electric capacity again, input resistance is at 500K, 330K180K, the discharge circuit of 100K Ω carries out traditional oscillograph discharge performance test, record the voltage in power-off 1s, through test, discovery in the internal resistance of oscilloprobe when 100M Ω is above, the actual discharge magnitude of voltage recording and the error rate of theoretical discharge voltage value meet IECEE requirement at < < Measure accuracy and tolerances > > for the precision of the measuring equipment in CB system laboratory.This requirement is defined in measuring voltage in 1000V, and frequency is in 1KHZ time, and the error of permission is ± 1.5%.
In the present invention the input resistance of sample circuit 5 according to its above-mentioned test setting for being not less than 100M Ω.
Described sample circuit 5 is differential amplifier, and input capacitance is less than 25pF, is connected to the ADC Sampling Interface of DSP.
Refer to Fig. 2 A, schematic diagram for sample circuit 5 of the present invention, as can be seen from the figure, sample circuit 5 utilizes the front-end circuit of amplifier U1 to carry out filtering and step-down to external input voltage, carry out impedance matching simultaneously, produce voltage V0, and this V0 is produced to ADC0 and ADC1 differential signal through a differential amplifier circuit, notify a follower to produce frequency signal Fer simultaneously.On the basis of Fig. 2 A, in conjunction with Fig. 2 B, the signal ADC0, the ADC1 that from Fig. 2 A, obtain, Fer signal are accessed respectively in Fig. 2 B, through thyristor a plurality of and that connect, then the signal of output is connected to the REF3 pin of dsp processor.
Through above-mentioned signal, process, whether described dsp processor can obtain external input voltage is fast the peak value of alternating voltage and this alternating voltage.
Described man-machine interface 6 comprises keystroke interface, liquid crystal panel interface and the USB interface that connects control button.
This man-machine interface 6 can be connected to respectively outside different IO equipment and realize different functions, wherein keystroke interface connects external key, and this button mainly can be controlled work and cut-off work and the demonstration of the external data when liquid crystal panel interface connecting fluid crystal panel of this capacitor discharge tester.
Described power circuit 2 can transform the outside civil power obtaining from power switch 1 and output voltage be ± direct current of 12V, and further this 12V direct current is passed through to voltage stabilizing step-down and be converted to 3.3V and 1.9 voltages.Wherein said ± 12V direct current by dsp processor to 32 power supplies of relay 31 and driving circuit, described+3.3V direct current and+1.9V direct current powers to dsp processor.
Refer to Fig. 3, this figure is power circuit 2 connection diagrams of the present invention, as can be seen from the figure external voltage is being accessed after two input ends, can through multistage filtering, step-down, export respectively 3.3V and 1.9V voltage, about the concrete principle of work of this circuit diagram and the chip those skilled in the art that select, can obtain, this place is not specifically introduced.
The capacitor discharge tester of the present invention with above structure and principle of work can meet different technical standards, specifically sees the following form 1:
Table 1 capacitor discharge tester of the present invention meets normal conditions
In addition, the applicant has also carried out accuracy validation for this capacitor discharge tester, the proficiency testing on the 12E27Plug Discharge Test sample having carried out at IFM, and concrete the result sees the following form respectively 2:
Table 2 capacitor discharge tester and IFM12E27Plug Discharge Test proficiency testing are compared
Median and the NIQP data of checking report in above-mentioned table 2, have been taken passages, and calculated this Z and compared mark, wherein | Z| < 3.0 is acceptables, and the data maximal value of utilizing capacitor discharge tester of the present invention to record also only has 0.539593.
The applicant also contrasts this capacitor discharge tester and traditional oscillograph test result in addition, and concrete comparing result sees the following form 3:
Table 3 capacitor discharge tester test data and oscillograph comparing
Capacitor discharge tester test data and the comparison of oscillograph data as can be seen from Table 3, when when during 1s, maximum deviation is 0.55%, 2s, maximum deviation is 0.81%, 10s, maximum deviation is 0.1V, 37% time to peak maximum deviation is 1.8%.
By the comparison of these two proficiency testings and oscilloscope measurement data, the equipment of having verified has higher accuracy and precision, can meet the testing requirement of capacitor discharge.
The present invention also provides a kind of method of testing of capacitor discharge tester, and it comprises the following steps:
Step 1: detect and record outside equipment under test and connect external voltage cycle and peak value, judgement is direct current or interchange.
This step is mainly to provide parameter for the practical operation in subsequent step.If direct current directly carries out following steps, and ignore the mensuration in cycle.
Step 2: the cycle of recording according to step 1 and peak value externally voltage are crossed theory time delay disconnection during zero point, make outside equipment under test be equivalent to externally voltage theoretical peak place and disconnect, and start timing simultaneously.
Wherein delay time is 1/4 of the external voltage cycle.
Less for the cycle, frequency is compared with little voltage signal, disconnecting external power supply when it detects peak signal, and actually deenergization constantly peak value passed through.So the data that record according to step 1 start disconnecting external voltage in advance.
Step 3: detect and record outside equipment under test sparking voltage and electric discharge duration, record moment t when this sparking voltage is down to peak value 37% 1.
Step 4: record moment t when this sparking voltage is down to 60V 2.
Moment t 1, t 2it is the important parameter that will record.
Step 5: do not recording in the same time sparking voltage value respectively, the different moment comprises 1s, 2s, 10s and 5min.
And at t 1, the magnitude of voltage that constantly records of 1s, 2s, 10s and 5min is also according to standard, to weigh the important parameter of outside equipment under test discharge performance.
Step 6: detect and finish.
When the 5min time then, detection of end, by the cycle of the detected voltage detecting, peak value; And magnitude of voltage when 1s, 2s, 10s; Moment t 1, t2; And the voltage curve of the electric discharge in the time at 5min, by man-machine interface, externally show screen display.
In sum, capacitor discharge tester provided by the invention adopts relay 31 and dsp processor as control section, adopt simultaneously and be connected to the supply voltage that the sample circuit 5 of dsp processor can the outside equipment under test of high-precision sampling, when this supply voltage peak value, disconnect relay 31, and recording the sparking voltage of this outside equipment under test, its sampling precision is high can disconnect relay 31 accurately at peak value place; It is owing to having adopted output resistance to be greater than the sample circuit 5 of 100M Ω, can be for detection of the different outside equipment under test of test, can meet a plurality of different testing standards, comprise GB4706.1/GB4943.1/GB7260.1/GB9706.1/GB8898, its versatility is good; Reduced traditional measuring error of utilizing oscillograph observation judgement sparking voltage to cause because of manual operation inconvenience.
Originally be the first detection to outside equipment under test external voltage of method of testing that this capacitor discharge tester providing is provided, after power-off, for this sparking voltage, can detect this sparking voltage and drop to maximum input voltage peak value 37% or 60V time used; Can also detect externally equipment under test power-off afterwards respectively at t simultaneously 1, 1s, 2s, 10s and sparking voltage value in the 5min time.Particularly on the basis of the structure based on above-mentioned capacitor discharge tester, utilize dsp processor, relay and 12 sample circuits can determine accurately fast power-cut time, and can utilize dsp processor to carry out compensation of delay, obtain each magnitude of voltage accurately.
The above, for the person of ordinary skill of the art, can make other various corresponding changes and distortion according to technical scheme of the present invention and technical conceive, and all these changes and distortion all should belong to the protection domain of the claims in the present invention.

Claims (6)

1. a capacitor discharge tester, has body structure, it is characterized in that, comprising:
The power switch that connects outside civil power; And the power circuit and the executive circuit that are connected with this power switch; Control circuit; The sample circuit one end and the man-machine interface that are connected with control circuit;
Described power circuit is connected with control circuit, and described executive circuit is connected with control circuit, and for connecting outside equipment under test, the described sample circuit other end is connected between executive circuit and outside equipment under test;
Described executive circuit comprises driving circuit and relay;
Described control circuit is 16 TMS320F2816 type dsp processors that comprise ADC Sampling Interface.
2. capacitor discharge tester as claimed in claim 1, is characterized in that, described man-machine interface comprises keystroke interface, liquid crystal panel interface and the USB interface that connects control button.
3. capacitor discharge tester as claimed in claim 1, it is characterized in that, the voltage of power circuit output is ± 12V direct current, 3.3V direct current and 1.9V direct current, described ± 12V direct current by dsp processor to relay and drive circuitry, described+3.3V direct current and+1.9V direct current powers to dsp processor.
4. capacitor discharge tester as claimed in claim 1, is characterized in that, described sample circuit is differential amplifier, and its input impedance is greater than 100M Ω, and input capacitance is less than 25pF, is connected to the ADC Sampling Interface of DSP.
5. a method of testing for capacitor discharge tester described in claim 1, is characterized in that, comprises the following steps:
Step 1: detect and record outside equipment under test and connect external voltage cycle and peak value, judgement is direct current or interchange;
Step 2: the cycle of recording according to step 1 and peak value externally voltage are crossed theory time delay disconnection during zero point, make outside equipment under test be equivalent to externally voltage theoretical peak place and disconnect, and start timing simultaneously;
Step 3: detect and record outside equipment under test sparking voltage and electric discharge duration, record moment t when this sparking voltage is down to peak value 37% 1;
Step 4: record moment t when this sparking voltage is down to 60V 2;
Step 5: do not recording in the same time sparking voltage value respectively;
Step 6: detect and finish, show testing result.
6. the used test method of capacitor discharge tester according to claim 5, is characterized in that, in step 2, delay time is 1/4 of the external voltage cycle; The moment different in step 5 comprise t 1, 1s, 2s, 10s and 5min.
CN201410009151.3A 2014-01-08 2014-01-08 Capacity discharge tester CN103713225A (en)

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN200950157Y (en) * 2006-09-28 2007-09-19 深圳市摩尔环宇通信技术有限公司 Capacitance discharging test device
CN101191812A (en) * 2006-11-27 2008-06-04 深圳市摩尔环宇通信技术有限公司 Capacitance discharging tester
CN202041590U (en) * 2010-12-31 2011-11-16 珠海格力新元电子有限公司 Capacitor charge and discharge tester
CN202533536U (en) * 2012-04-30 2012-11-14 福建省产品质量检验研究院 Capacitor discharging test detector
CN202600057U (en) * 2012-01-09 2012-12-12 宝山钢铁股份有限公司 Enablement integrated tester for high-capacity electrolytic capacitor
CN203759150U (en) * 2014-01-08 2014-08-06 深圳出入境检验检疫局工业品检测技术中心 Capacitance discharge tester

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN200950157Y (en) * 2006-09-28 2007-09-19 深圳市摩尔环宇通信技术有限公司 Capacitance discharging test device
CN101191812A (en) * 2006-11-27 2008-06-04 深圳市摩尔环宇通信技术有限公司 Capacitance discharging tester
CN202041590U (en) * 2010-12-31 2011-11-16 珠海格力新元电子有限公司 Capacitor charge and discharge tester
CN202600057U (en) * 2012-01-09 2012-12-12 宝山钢铁股份有限公司 Enablement integrated tester for high-capacity electrolytic capacitor
CN202533536U (en) * 2012-04-30 2012-11-14 福建省产品质量检验研究院 Capacitor discharging test detector
CN203759150U (en) * 2014-01-08 2014-08-06 深圳出入境检验检疫局工业品检测技术中心 Capacitance discharge tester

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
谢磊雷等: "不同安全标准的一次电路电容放电试验的测量方法研究", 《科技创新导报》 *
陈帆等: "电器产品电容放电测试方法和自动测试设备研究", 《家电科技》 *

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