CN204514975U - AC constant-current source, internal resistance of cell pick-up unit and cell tester - Google Patents
AC constant-current source, internal resistance of cell pick-up unit and cell tester Download PDFInfo
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- CN204514975U CN204514975U CN201520155319.1U CN201520155319U CN204514975U CN 204514975 U CN204514975 U CN 204514975U CN 201520155319 U CN201520155319 U CN 201520155319U CN 204514975 U CN204514975 U CN 204514975U
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Abstract
The utility model discloses a kind of AC constant-current source.AC constant-current source of the present utility model comprises the AC signal generating unit, control circuit, power amplification circuit, the capacitance that connect successively, and current sampling circuit; Control circuit adjusts the AC signal that AC signal generating unit exports according to the sampled result of current sampling circuit, the drive singal of generating power amplifying circuit; Between power amplification circuit and capacitance, be serially connected with an inductance, the resonance frequency of the LC resonant circuit that this inductance and capacitance form equals the frequency that AC signal generating unit outputs signal.The utility model also can comprise a biasing circuit further, for according to the DC component in control circuit or power amplification circuit output signal, in the output signal of AC signal generating unit, applies a reverse direct current signal.The invention also discloses a kind of internal resistance of cell pick-up unit and cell tester.Utilize the utility model can obtain internal resistance of cell measurement data more accurately.
Description
Technical field
The utility model relates to a kind of AC constant-current source, particularly relates to a kind of AC constant-current source measuring the internal resistance of cell for ac-current inject method.
Background technology
The use of present accumulator is very general, detects quickly and accurately and safeguard also day by day urgent to accumulator.It is the decisive parameter judging accumulator capacity situation that accumulator internal resistance is recognized, and internal resistance of cell pick-up unit can matching battery producer detect at production line fast.Therefore by measuring the internal resistance of cell, battery is assessed.Existing cell tester all has internal resistance of cell measuring ability usually.
Existing internal resistance of cell detection technique mainly comprises following a few class:
(1) densimetry:
Densimetry carrys out estimating battery internal resistance mainly through measuring battery liquid density, is usually used in the internal resistance measurement of open type lead-acid accumulator, and cannot measure the accumulator internal resistance of sealing, therefore the scope of application is extremely narrow.
(2) open-circuit voltage method:
Open-circuit voltage method estimates the internal resistance of cell by measuring battery terminal voltage, due to the battery that a capacity is very little, its terminal voltage under floating charge state still can be acted normally, and therefore the measuring accuracy of open-circuit voltage method is very poor, even can draw error result.
(3) direct-current discharge method:
Direct-current discharge method carries out transient large current discharge to battery, fallen, and utilize Ohm law to calculate the internal resistance of cell by the transient voltage measuring battery.This method is widely applied in practice, but also there are some critical defects, such as, its internal resistance detection can only carry out under static state or off-line state, cannot carry out on-line measurement, and heavy-current discharge can cause damage to battery, thus affect quality and the life-span of battery.
(4) ac-current inject method:
Ac-current inject method is by injecting a constant ac current signal to battery, measures voltage responsive signal and the phase differential between the two at battery two ends, utilizes the formula of impedance determination internal resistance of cell.The method does not need to discharge to battery, and therefore can not have an impact to battery performance, and can realize the on-line checkingi of the internal resistance of cell, measurement result is accurate.Ac-current inject method more and more becomes the main stream approach that the internal resistance of cell is measured.
When adopting ac-current inject method to carry out resistance measurement, the output performance as the AC constant-current source of exciting signal source directly has influence on the accuracy of measurement result.Current common way directly adopts existing AC constant-current source to be connected in series a capacitance to form exciting signal source.But when adopting in this way, on the one hand, because capacitance has capacitive reactance in alternating circuit, output current can be caused inadequate; On the other hand, the AC signal waveform of generation often understands distortion, has had influence on the accuracy that the internal resistance of cell is measured.
Utility model content
Technical problem to be solved in the utility model is to overcome the deficiencies in the prior art, provides a kind of AC constant-current source, during the exciting signal source utilizing it to measure as the ac-current inject method internal resistance of cell, can obtain measurement data more accurately.
The utility model specifically solves the problems of the technologies described above by the following technical solutions:
A kind of AC constant-current source, comprises the AC signal generating unit, control circuit, power amplification circuit, the capacitance that connect successively, and current sampling circuit; Control circuit adjusts the AC signal that AC signal generating unit exports according to the sampled result of current sampling circuit, the drive singal of generating power amplifying circuit; Between power amplification circuit and capacitance, be serially connected with an inductance, the resonance frequency of the LC resonant circuit that this inductance and described capacitance form equals the frequency that AC signal generating unit outputs signal.
Further, this AC constant-current source also comprises a biasing circuit, for according to the DC component in control circuit or power amplification circuit output signal, in the output signal of AC signal generating unit, applies a reverse direct current signal.
As one of them preferred version, described biasing circuit comprises the analog to digital converter, control module, the digital to analog converter that connect successively, the input end of analog to digital converter is connected with the output terminal of described control circuit or power amplification circuit, and the output terminal of digital to analog converter is connected with the input end of described control circuit; Analog to digital converter gathers the output signal of described control circuit or power amplification circuit, calculates the DC component in its signal by control module, and then domination number weighted-voltage D/A converter exports a reverse direct current signal.
As wherein another preferred version, described biasing circuit comprises the amplitude limiter circuit, the low-pass filter circuit that connect successively, the input end of amplitude limiter circuit is connected with the output terminal of described control circuit, and the output terminal of low-pass filter circuit is connected with the input end of described control circuit; Amplitude limiter circuit limits the positive and negative crest voltage of AC signal, and when the positive and negative crest voltage of AC signal exceedes limits value, amplitude limiter circuit exports reverse AC signal, then exports direct current signal through low-pass filtering.
Preferably, described control circuit comprises an error amplifier, the reference signal input end of this error amplifier is connected with the output terminal of the output terminal of described low-pass filter circuit, AC signal generating unit, the feedback signal input terminal of error amplifier is connected with the output terminal of described current sampling circuit, and the output terminal of error amplifier is connected with the input end of described amplitude limiter circuit, the input end of power amplification circuit.
Also following technical scheme can be obtained according to identical utility model thinking:
A kind of internal resistance of cell pick-up unit, comprise the AC constant-current source for injecting constant current AC signal to mesuring battary, described AC constant-current source is AC constant-current source described in above arbitrary technical scheme.
A kind of cell tester, comprises internal resistance of cell pick-up unit described above.
Further, described cell tester also comprises the voltage check device for detecting mesuring battary both end voltage.
Compared to existing technology, the utility model has following beneficial effect:
The utility model by being connected in series impedance matching inductance between power amplification circuit with capacitance, and the resonance frequency of the resonant circuit making capacitance and this inductance form equals the frequency that AC signal generating unit outputs signal, thus eliminate the capacitive reactance of capacitance to AC signal, improve system output characteristics;
The DC component that the utility model specifies the principal element of AC constant-current source output waveform distortion measured for the internal resistance of cell first during output signal to by AC signal generating unit, in the output signal of AC signal generating unit, apply an equal-sized reverse direct current signal by biasing circuit, improve system output characteristics further;
The utility model structure is simple, realizes with low cost.
Accompanying drawing explanation
Fig. 1 is the structured flowchart of a preferred embodiment of the utility model AC constant-current source;
Fig. 2 is the theory diagram of a kind of implementation of biasing circuit;
Fig. 3 is the theory diagram of the another kind of implementation of biasing circuit;
Fig. 4 is a kind of specific implementation circuit of biasing circuit.
Embodiment
Below in conjunction with accompanying drawing, the technical solution of the utility model is described in detail:
When utilizing ac-current inject method to carry out internal resistance of cell measurement, need to access capacitance between exciting signal source and mesuring battary, export to avoid battery DC and exciting signal source is had an impact, but because electric capacity has capacitive reactance in alternating circuit, output current can be caused inadequate, for this reason, the utility model accessed an inductance before capacitance, and the resonance frequency of the inductance value LC resonant circuit that just makes itself and capacitance form equals the frequency that AC signal generating unit outputs signal, i.e. the output frequency of AC constant-current source.Like this, the output impedance of whole resonant circuit is zero, thus avoids the harmful effect that capacitance outputs signal AC constant-current source.
Find that the output of said structure AC constant-current source can exist waveform distortion to a certain degree in practice, analyze discovery after deliberation, because AC signal generating unit outputs signal and nonideal waveform, wherein can there is small DC voltage component, accumulative through after a while, the DC voltage that can add up at capacitance two ends thus cause current signal distortion.And existing AC/DC source is paid close attention to usually is the distorted signals that higher hamonic wave causes, there is not the solution of the problems referred to above.For head it off, the utility model is provided with in AC constant-current source can according to the DC component in control circuit or power amplification circuit output signal, the biasing circuit of the direct current signal that applying one is contrary with described DC component direction in the output signal of AC signal generating unit.
Fig. 1 shows the basic structure of a preferred embodiment of the utility model AC constant-current source.As shown in Figure 1, AC constant-current source in this embodiment comprises the AC signal generating unit, control circuit, power amplification circuit, inductance, the capacitance that connect successively, for the current sampling circuit of sampling to the output current of AC constant-current source, and for applying the biasing circuit of a reverse direct current signal in the output signal to AC signal generating unit; Wherein, AC signal generating unit is for generating interchange reference signal; Control circuit adjusts the interchange reference signal that AC signal generating unit exports according to the sampled result of current sampling circuit, the drive singal of generating power amplifying circuit; Power amplification circuit exports after AC signal being amplified successively after inductance and capacitance.As shown in Figure 1, the input signal of biasing circuit can obtain from the output terminal of the output terminal of control circuit or power amplification circuit.
Biasing circuit of the present utility model can adopt various ways to realize, and namely Fig. 2 shows wherein a kind of implementation.This biasing circuit utilizes the control module (such as MCU) with logical operation function to realize, specifically as shown in Figure 2, comprise the analog to digital converter, control module, the digital to analog converter that connect successively, the input end of analog to digital converter is connected with the output terminal of control circuit or power amplification circuit, and the output terminal of digital to analog converter is connected with the input end of described control circuit.Control circuit in the present embodiment as shown in Figure 2, comprise an error amplifier, the AC signal that its reference signal input end input exchange signal generating unit exports and the DC offset voltage that biasing circuit exports, the voltage signal that feedback signal input terminal input current sample circuit exports, by the output driving power amplifying circuit of error amplifier; Current sampling circuit comprises the measuring resistance of one group of corresponding different constant current value, and switches with relay, and ohmically ac voltage signal is outputted to control circuit.
The implementation of Fig. 2 can adjust reverse direct current signal real-time and accurately according to the DC component in AC signal, but due to control assemblies such as needs MCU, it is embodied as originally higher, and therefore the utility model preferably adopts the biasing circuit shown in Fig. 3.As shown in Figure 3, this biasing circuit comprises the amplitude limiter circuit, the low-pass filter circuit that connect successively, and the input end of amplitude limiter circuit is connected with the output terminal of described control circuit, and the output terminal of low-pass filter circuit is connected with the input end of described control circuit.Amplitude limiter circuit limits the positive and negative crest voltage of AC signal, and when the positive and negative crest voltage of AC signal exceedes limits value, amplitude limiter circuit exports reverse AC signal, then exports direct current signal through low-pass filtering.
Fig. 4 shows a kind of physical circuit adopting Fig. 3 structure.As shown in the figure, the reference signal that AC signal generating unit exports and current sampling signal are added in forward and the reverse input end of error amplifier OP1, the output of error amplifier is connected to amplifier OP3, the reverse input end of OP5, and be added with negative positive limiting voltage, amplifier OP3 and OP4 forms positive amplitude limit function, when the input of amplifier OP3 backward end is greater than zero, diode exports negative voltage, same amplifier OP5 and OP6 forms negative amplitude limit function, when the input of amplifier OP5 backward end is less than zero, diode exports positive voltage, again by RC filtering, signal buffer exports, and be added with reference signal, composition closed-loop control.
Claims (8)
1. an AC constant-current source, comprises the AC signal generating unit, control circuit, power amplification circuit, the capacitance that connect successively, and current sampling circuit; Control circuit adjusts the AC signal that AC signal generating unit exports according to the sampled result of current sampling circuit, the drive singal of generating power amplifying circuit; It is characterized in that, be serially connected with an inductance between power amplification circuit and capacitance, the resonance frequency of the LC resonant circuit that this inductance and described capacitance form equals the frequency that AC signal generating unit outputs signal.
2. AC constant-current source as claimed in claim 1, it is characterized in that, this AC constant-current source also comprises a biasing circuit, for according to the DC component in control circuit or power amplification circuit output signal, in the output signal of AC signal generating unit, applies a reverse direct current signal.
3. AC constant-current source as claimed in claim 2, it is characterized in that, described biasing circuit comprises the analog to digital converter, control module, the digital to analog converter that connect successively, the input end of analog to digital converter is connected with the output terminal of described control circuit or power amplification circuit, and the output terminal of digital to analog converter is connected with the input end of described control circuit; Analog to digital converter gathers the output signal of described control circuit or power amplification circuit, calculates the DC component in its signal by control module, and then domination number weighted-voltage D/A converter exports a reverse direct current signal.
4. AC constant-current source as claimed in claim 2, it is characterized in that, described biasing circuit comprises the amplitude limiter circuit, the low-pass filter circuit that connect successively, and the input end of amplitude limiter circuit is connected with the output terminal of described control circuit, and the output terminal of low-pass filter circuit is connected with the input end of described control circuit; Amplitude limiter circuit limits the positive and negative crest voltage of AC signal, and when the positive and negative crest voltage of AC signal exceedes limits value, amplitude limiter circuit exports reverse AC signal, then exports direct current signal through low-pass filtering.
5. AC constant-current source as claimed in claim 4, it is characterized in that, described control circuit comprises an error amplifier, the reference signal input end of this error amplifier is connected with the output terminal of the output terminal of described low-pass filter circuit, AC signal generating unit, the feedback signal input terminal of error amplifier is connected with the output terminal of described current sampling circuit, and the output terminal of error amplifier is connected with the input end of described amplitude limiter circuit, the input end of power amplification circuit.
6. an internal resistance of cell pick-up unit, comprise the AC constant-current source for injecting constant current AC signal to mesuring battary, it is characterized in that, described AC constant-current source is AC constant-current source described in any one of Claims 1 to 5.
7. a cell tester, comprises internal resistance of cell pick-up unit as claimed in claim 6.
8. cell tester as claimed in claim 7, is characterized in that, also comprising the voltage check device for detecting mesuring battary both end voltage.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520155319.1U CN204514975U (en) | 2015-03-18 | 2015-03-18 | AC constant-current source, internal resistance of cell pick-up unit and cell tester |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520155319.1U CN204514975U (en) | 2015-03-18 | 2015-03-18 | AC constant-current source, internal resistance of cell pick-up unit and cell tester |
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| CN204514975U true CN204514975U (en) | 2015-07-29 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201520155319.1U Withdrawn - After Issue CN204514975U (en) | 2015-03-18 | 2015-03-18 | AC constant-current source, internal resistance of cell pick-up unit and cell tester |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104678134A (en) * | 2015-03-18 | 2015-06-03 | 艾德克斯电子（南京）有限公司 | AC constant current source, internal resistance detecting device of cell and cell testing instrument |
| CN105548725A (en) * | 2015-12-16 | 2016-05-04 | 黑龙江省计量检定测试院 | Online detector for super capacitor and internal resistance detection method based on detector |
| CN114217659A (en) * | 2021-12-03 | 2022-03-22 | 国网浙江省电力有限公司建德市供电公司 | Voltage-controlled alternating current constant current source circuit and arc suppression coil automatic compensation calibration device |
-
2015
- 2015-03-18 CN CN201520155319.1U patent/CN204514975U/en not_active Withdrawn - After Issue
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104678134A (en) * | 2015-03-18 | 2015-06-03 | 艾德克斯电子（南京）有限公司 | AC constant current source, internal resistance detecting device of cell and cell testing instrument |
| CN104678134B (en) * | 2015-03-18 | 2017-06-20 | 艾德克斯电子（南京）有限公司 | AC constant-current source, internal resistance of cell detection means and cell tester |
| CN105548725A (en) * | 2015-12-16 | 2016-05-04 | 黑龙江省计量检定测试院 | Online detector for super capacitor and internal resistance detection method based on detector |
| CN114217659A (en) * | 2021-12-03 | 2022-03-22 | 国网浙江省电力有限公司建德市供电公司 | Voltage-controlled alternating current constant current source circuit and arc suppression coil automatic compensation calibration device |
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| Date | Code | Title | Description |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| AV01 | Patent right actively abandoned |
Granted publication date: 20150729 Effective date of abandoning: 20170620 |
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| AV01 | Patent right actively abandoned |