CN202330525U - Current range determination device - Google Patents
Current range determination device Download PDFInfo
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- CN202330525U CN202330525U CN2011204621898U CN201120462189U CN202330525U CN 202330525 U CN202330525 U CN 202330525U CN 2011204621898 U CN2011204621898 U CN 2011204621898U CN 201120462189 U CN201120462189 U CN 201120462189U CN 202330525 U CN202330525 U CN 202330525U
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Abstract
The utility model discloses a current range determination device which is used for carrying out current measurement on neutral points of transformers. The current range determination device comprises a preprocessing circuit, an absolute value circuit, N comparison circuits and N isolation circuits. According to the utility model, through letting measurement results of a Hall current sensor with the maximal range in a current sampling circuit in the comparison circuits, comparison results are input into an I/O (input/output) port of a controller by the isolation circuits, then the range of current measurement is directly determined through reading the level of the I/O port, thereby solving the problems that in the prior art, a Hall current sensor with a small range is easy to damage, the current sampling of a sampling circuit and an operation of range determination are performed relatively complexly and need long processing time, and the like.
Description
Technical field
The utility model relates to a kind of current range decision maker, particularly relates to a kind of transformer neutral point, large-scale current range decision maker.
Background technology
During the operation of the big earthed return of high-voltage direct current one pole, huge DC current flows into the earth through direct current grounding pole, and in a big way, causes earthy significant change, and this earthy variation possibly exert an influence for the AC system of areal.Two transformer stations that are in different DC potentials constitute the loop through transmission line of electricity; DC current is introduced transformer neutral point and Transformer Winding; Make transformer the DC magnetic biasing phenomenon occur; Cause transformer noise to increase, vibration aggravation etc., the harmonic distortion that overheated and AC network also possibly take place increases.The operation of this direct current one pole or through the earth operation to the influence that exchanges when serious even possibly cause the damage of transformer or the malfunction of protection.According to above-mentioned situation, the DC current that transformer neutral point passes through will detect in real time, if any grasping and control the influence of direct current to transformer in this way fast in time to the scheduling reflection unusually.
The electric current variation range of transformer neutral point is very big, usually in 50A, but some unexpected situation; May reach more than the 100A, this has brought very big difficulty with regard to the measurement of giving neutral point current, and the electric current of neutral point is made up of DC current and alternating current; In the prior art the logical Hall current sensor that adopts of the measurement of neutral point current is measured; Yet the Hall current sensor that range ability is big all is the 1%F.S. precision usually, and when measuring less electric current, the error of bringing is too big.Therefore, in order to guarantee the precision of large-range measuring, need usually to adopt the Hall current sensor of a plurality of different ranges to measure together, sample its output result after, through controller relatively, select the high measurement result of precision.Yet in this case, a plurality of Hall current sensors must be in running order always; If the time that big electric current occurs is longer, the Hall current sensor that range is little is easy to damage, and sampling back result of determination; Sample circuit is comparatively complicated, and sampled result is inner to controller, judges that range is also comparatively complicated; Consume a large amount of controller resources, need the long processing time.
In sum; Can know in the prior art that measurement to the transformer neutral point electric current exists the damage easily of the little Hall current sensor of range, sample circuit and judge that range is comparatively complicated and need than problems such as long process times; Therefore be necessary to propose improved technological means in fact, solve this problem.
The utility model content
For overcoming the deficiency that above-mentioned prior art exists; The fundamental purpose of the utility model is to provide a kind of current range decision maker; Its measurement result through the Hall current sensor that range in the current sampling circuit is maximum feeds comparator circuit; Comparative result is directly inputted to the I/O port of controller through buffer circuit; Directly determine the range of current measurement through the level that reads the I/O port, solved range that prior art exists little Hall current sensor damage easily, sample circuit and judge that range is comparatively complicated and need than problems such as long process times.
For reaching above-mentioned and other purpose, a kind of current range decision maker of the utility model is applied to the current sampling circuit of the current measurement of a pair of transformer neutral point, and wherein, this current range decision maker comprises at least:
Pre-process circuit; Be connected in the maximum Hall current sensor of range in this current sampling circuit, the unipolar signal that this pre-process circuit is exported this Hall current sensor is processed into bipolar signal and isolates and exports an absolute value circuit to after amplification is maybe amplified the bipolar signal isolation of this Hall current sensor output;
Absolute value circuit is connected in the output terminal of this pre-process circuit, this absolute value circuit with pretreated this bipolar signal take absolute value only want range signal after the output absolute value signal to comparator circuit;
N comparator circuit all is connected in the output terminal of this absolute value circuit, and each comparator circuit compares the back with this absolute value signal and corresponding benchmark and obtains N elementary range signal output; And
N buffer circuit, correspondence are connected in this N comparator circuit, and each buffer circuit is isolated N the secondary range signal that obtains to be fit to the subsequent process circuit level with this N elementary range signal and subsequent process circuit.
Further; This pre-process circuit comprises first operational amplifier, first resistance and the 3rd resistance at least; Wherein, The output voltage of the Hall current sensor that this range is maximum links to each other with the negative of this first operational amplifier through this first resistance, and a bias voltage links to each other with the positive of this first operational amplifier, connects the 3rd resistance between the negative of this first operational amplifier and the output.
Further, this bias voltage links to each other with the positive of this first operational amplifier through one second resistance.
Further; This absolute value circuit comprises second operational amplifier, the 3rd operational amplifier, the 4th resistance, the 5th resistance, the 6th resistance, the 7th resistance, the 8th resistance, the 9th resistance, first fast diode and second fast diode; The output of this pre-process circuit links to each other through the negative of the 4th resistance with this second operational amplifier; The positive ground connection of this second operational amplifier connects the 5th resistance between negative and the output; The output of this pre-process circuit links to each other through the positive of the 9th resistance with the 3rd operational amplifier simultaneously; The 7th resistance and this first fast diode anti-series; The 8th resistance and this second fast diode anti-series; Two series circuits are connected between the negative and output of the 3rd operational amplifier, this first fast diode and this second fast diode in the opposite direction; The 7th resistance links to each other through the negative of the 6th resistance with this second operational amplifier with the contact of this second fast diode with the contact or the 8th resistance of this first fast diode.
Further, the resistance of the 6th resistance is the half the of the 4th resistance.
Further, this comparator circuit comprises comparer and current-limiting resistance, and the output of this absolute value circuit is received the positive of this comparer through this current-limiting resistance, and the negative of this comparer connects the voltage of measuring the range correspondence that electric current institute will divide.
Further, the quantity N of this comparator circuit is by the quantity decision of the Hall current sensor of the needed different ranges of this current sampling circuit, and N is that the quantity of Hall current sensor subtracts 1.
Further; This buffer circuit comprises photo-coupler, input current-limiting resistance and pull-up resistor, and wherein, the output of the comparer of a comparator circuit links to each other with this photo-coupler emission side through this input current-limiting resistance; This photo-coupler output of this pull-up resistor one side joint, another side joint power supply.
Further, the output signal of this buffer circuit is directly inputted to the I/O pin of the controller of this current sampling circuit.
Further, the quantity of the photo-coupler of this N buffer circuit is identical with the quantity of the comparer of this N comparator circuit, and corresponding one by one.
Compared with prior art; A kind of current range decision maker of the utility model; Measurement result through the Hall current sensor that range in the current sampling circuit is maximum feeds comparator circuit; Comparative result is directly inputted to the I/O port of controller through buffer circuit; Directly determine the range of current measurement through the level that reads the I/O port, solved range that prior art exists little Hall current sensor damage easily, sample circuit and judge that range is comparatively complicated and need than problems such as long process times.
Description of drawings
Fig. 1 by a kind of current range decision maker of the utility model the circuit structure diagram of current sampling circuit of application;
Fig. 2 is the circuit structure diagram of the preferred embodiment of current range decision maker among Fig. 1.
Embodiment
Below through the embodiment of specific instantiation and accompanying drawings the utility model, those skilled in the art can be understood other advantage and the effect of the utility model easily by the content that this instructions disclosed.The utility model also can be implemented or use through other different instantiation, and each item details in this instructions also can be carried out various modifications and change based on different viewpoints and application under the spirit that does not deviate from the utility model.
Fig. 1 by a kind of current range decision maker of the utility model the circuit structure diagram of current sampling circuit of application.The current sampling circuit that a kind of current range decision maker of the utility model is used; Be mainly used in the current sample to transformer neutral point, it comprises at least: N Hall current sensor 101, current range decision maker 102, controller 103, multi-channel analog switch circuit 104 and analog to digital conversion circuit (ADC) 105.Wherein, One maximum (in the utility model preferred embodiment, being made as Hall current sensor 1) of range is connected with current range decision maker 102 in N the Hall current sensor 101; The output result of Hall current sensor 1 is directly inputted to the I/O pin of controller 103 through current range decision maker 102; Thereby judge the measurement range of electric current; Controller 103 is selected corresponding Hall current sensor passage through control multi-channel analog switch circuit (MUX) 104, through analog to digital conversion circuit 105, digital signal is input to controller 103.
Fig. 2 is the circuit structure diagram of preferred embodiment of the current range decision maker of the utility model among Fig. 1.Specifically, the current range decision maker of the utility model comprises at least: pre-process circuit 21, absolute value circuit 22, a N comparator circuit 23 and N buffer circuit 24.
Wherein, pre-process circuit 21 is used for the unipolar signal that samples is processed into bipolar signal and isolate amplifies maybe the bipolar signal that samples to be isolated and amplify, and it comprises first operational amplifier 210, first resistance R 1, second resistance R and the 3rd resistance R 3; Wherein, the output voltage V s of the Hall current sensor (being Hall current sensor 1) that range is maximum links to each other with the negative of first operational amplifier 210 through first resistance R 1, and a bias voltage Voff links to each other with the positive of first operational amplifier 210 through second resistance R 2; Connect the 3rd resistance R 3 between the negative of first operational amplifier and the output; The ratio of the 3rd resistance R 3 and first resistance R 1 is signal amplification factor, and at this, second resistance R 2 plays the effect of protection first operational amplifier 210; Hall current sensor detects positive and negative electric current; One pole output or bipolar output, if one pole output, pre-process circuit 21 is transformed to bipolar output with it; And its output signal is amplified, and bias voltage is the corresponding voltage of zero current; If bipolar output, pre-process circuit 21 plays the voltage follow effect, and its output signal is amplified, and bias voltage is zero, i.e. ground connection.
Below will cooperate Fig. 2 to further specify the principle of work of the utility model through a specific embodiment: in this specific embodiment, pre-process circuit 21 comprises: operational amplifier OPA1, resistance R 1, resistance R 2, resistance R 3, wherein; The output voltage V s of the Hall current sensor (Hall current sensor 1) that range is maximum links to each other with the negative of operational amplifier U1 through resistance R 1, and bias voltage Voff links to each other with the positive of operational amplifier OPA1 through resistance R 2, connecting resistance R3 between the negative of operational amplifier OPA1 and the output; Resistance R 3 is a signal amplification factor with the ratio of resistance R 1; Resistance R 2 plays the effect of protection operational amplifier OPA1, and the Hall current sensor output current of being selected for use is 12 ± 8mA, and sampling resistor is 200 Ω; Output voltage is 2.4 ± 1.6V; Bias voltage is selected 2.4V, is bipolar output with the output transform of one pole, and resistance R 1 is got 330 Ω; Resistance R 3 is got 1k Ω; The output voltage of pre-process circuit is about-4.8～+ 4.8V, resistance R 2 is got 330 Ω, and operational amplifier OPA1 adopts OPA2604.
The number of comparators of comparator circuit 23 is by measuring the range quantity decision that electric current is divided, and promptly by the quantity decision of the Hall current sensor that adopts, present embodiment adopts the Hall current sensor of three ranges; Need two comparator circuits; The output of absolute value circuit 22 just is connected with comparator C OMP1 through current-limiting resistance R10, just is connected with comparator C OMP2 through current-limiting resistance R11, and the negative of comparator C OMP1 connects comparative voltage V1; The negative of comparator C OMP2 connects comparative voltage V2; Comparative voltage V1, V2 determine that by the range of Hall current sensor the measurement range of the Hall current sensor that range is maximum is set at 0-± 120A, and the output voltage of corresponding absolute value circuit 2 is 0-4.8V; The measurement range of two other Hall current sensor is respectively 0-± 25A, 0-± 5A; The output voltage of the corresponding absolute value circuit 2 of 5A, 25A is 0.2V, 1V, thereby comparative voltage V1 gets 0.2V, and comparative voltage V2 gets 1V; Resistance R 10, R11 are 47 Ω, and comparator C OMP1, COMP2 adopt TLV3501.
It is thus clear that; A kind of current range decision maker of the utility model; Measurement result through the Hall current sensor that range is maximum feeds comparator circuit; Comparative result is directly inputted to the I/O port of controller through buffer circuit, directly determine the range of current measurement through the level that reads the I/O port, has solved range that prior art exists little Hall current sensor damage easily, sample circuit and judges that range is comparatively complicated and need than problems such as long process times; Compared with prior art, the utlity model has following beneficial effect:
The first, judge the current measurement range with mimic channel, circuit is simple, be easy to realize, and response is fast;
The second, through photo-coupler mimic channel, controller are isolated mutually, make it mutually not influence;
Three, current square-wave signal can be directly inputted to controller I/O pin, and as trigger pip, controller can be judged the measurement range of electric current fast, and it is few to take resource, and efficient is high;
Four, judge that range does not need the output result of each current sensor, before judging, other current sensors can not worked, and can not damage because of long term overloading to protect it.
The foregoing description is the principle and the effect thereof of illustrative the utility model only, but not is used to limit the utility model.Any those skilled in the art all can be under the spirit and category of the utility model, and the foregoing description is modified and changed.Therefore, the rights protection scope of the utility model should be listed like claims.
Claims (10)
1. current range decision maker is applied to the current sampling circuit of the current measurement of a pair of transformer neutral point, it is characterized in that this current range decision maker comprises at least:
Pre-process circuit; Be connected in the maximum Hall current sensor of range in this current sampling circuit, the unipolar signal that this pre-process circuit is exported this Hall current sensor is processed into bipolar signal and isolates and exports an absolute value circuit to after amplification is maybe amplified the bipolar signal isolation of this Hall current sensor output;
Absolute value circuit is connected in the output terminal of this pre-process circuit, this absolute value circuit with pretreated this bipolar signal take absolute value only want range signal after the output absolute value signal to comparator circuit;
N comparator circuit all is connected in the output terminal of this absolute value circuit, and each comparator circuit compares the back with this absolute value signal and corresponding benchmark and obtains N elementary range signal output; And
N buffer circuit, correspondence are connected in this N comparator circuit, and each buffer circuit is isolated N the secondary range signal that obtains to be fit to the subsequent process circuit level with this N elementary range signal and subsequent process circuit.
2. current range decision maker as claimed in claim 1; It is characterized in that: this pre-process circuit comprises first operational amplifier, first resistance and the 3rd resistance at least; Wherein, The output voltage of the Hall current sensor that this range is maximum links to each other with the negative of this first operational amplifier through this first resistance, and a bias voltage links to each other with the positive of this first operational amplifier, connects the 3rd resistance between the negative of this first operational amplifier and the output.
3. current range decision maker as claimed in claim 2 is characterized in that: this bias voltage links to each other with the positive of this first operational amplifier through one second resistance.
4. current range decision maker as claimed in claim 1; It is characterized in that: this absolute value circuit comprises second operational amplifier, the 3rd operational amplifier, the 4th resistance, the 5th resistance, the 6th resistance, the 7th resistance, the 8th resistance, the 9th resistance, first fast diode and second fast diode; The output of this pre-process circuit links to each other through the negative of the 4th resistance with this second operational amplifier; The positive ground connection of this second operational amplifier connects the 5th resistance between negative and the output; The output of this pre-process circuit links to each other through the positive of the 9th resistance with the 3rd operational amplifier simultaneously; The 7th resistance and this first fast diode anti-series; The 8th resistance and this second fast diode anti-series; Two series circuits are connected between the negative and output of the 3rd operational amplifier, this first fast diode and this second fast diode in the opposite direction; The 7th resistance links to each other through the negative of the 6th resistance with this second operational amplifier with the contact of this second fast diode with the contact or the 8th resistance of this first fast diode.
5. current range decision maker as claimed in claim 4 is characterized in that: the resistance of the 6th resistance is half the for the 4th resistance.
6. current range decision maker as claimed in claim 1; It is characterized in that: this comparator circuit comprises comparer and current-limiting resistance; The output of this absolute value circuit is received the positive of this comparer through this current-limiting resistance, and the negative of this comparer connects the voltage of measuring the range correspondence that electric current institute will divide.
7. current range decision maker as claimed in claim 6 is characterized in that: the quantity N of this comparator circuit is by the quantity decision of the Hall current sensor of the needed different ranges of this current sampling circuit, and N is that the quantity of Hall current sensor subtracts 1.
8. current range decision maker as claimed in claim 1; It is characterized in that: this buffer circuit comprises photo-coupler, input current-limiting resistance and pull-up resistor; Wherein, The output of the comparer of one comparator circuit links to each other with this photo-coupler emission side through this input current-limiting resistance, this photo-coupler output of this pull-up resistor one side joint, another side joint power supply.
9. current range decision maker as claimed in claim 8 is characterized in that: the output signal of this buffer circuit is directly inputted to the I/O pin of the controller of this current sampling circuit.
10. current range decision maker as claimed in claim 9 is characterized in that: the quantity of the photo-coupler of this N buffer circuit is identical with the quantity of the comparer of this N comparator circuit, and corresponding one by one.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011204621898U CN202330525U (en) | 2011-11-18 | 2011-11-18 | Current range determination device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011204621898U CN202330525U (en) | 2011-11-18 | 2011-11-18 | Current range determination device |
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| Publication Number | Publication Date |
|---|---|
| CN202330525U true CN202330525U (en) | 2012-07-11 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2011204621898U Withdrawn - After Issue CN202330525U (en) | 2011-11-18 | 2011-11-18 | Current range determination device |
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| CN (1) | CN202330525U (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102445587A (en) * | 2011-11-18 | 2012-05-09 | 华东电力试验研究院有限公司 | Current sampling circuit and current range judging device thereof |
| CN104062487A (en) * | 2013-03-20 | 2014-09-24 | 鸿富锦精密工业(武汉)有限公司 | Voltage detection system |
| CN104076190A (en) * | 2013-03-29 | 2014-10-01 | 海洋王（东莞）照明科技有限公司 | Direct current detection circuit |
| CN104076188A (en) * | 2013-03-29 | 2014-10-01 | 海洋王（东莞）照明科技有限公司 | Alternating current detection circuit |
| CN104779958A (en) * | 2014-01-10 | 2015-07-15 | 亚德诺半导体集团 | Amplifying system |
| CN110794328A (en) * | 2019-10-30 | 2020-02-14 | 汉中一零一航空电子设备有限公司 | Detection circuit and detection method for detecting overload or short-circuit fault |
| CN114624492A (en) * | 2022-04-22 | 2022-06-14 | 西南交通大学 | Method for measuring potential difference of two remote transformer substation ground grids caused by direct current |
-
2011
- 2011-11-18 CN CN2011204621898U patent/CN202330525U/en not_active Withdrawn - After Issue
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102445587A (en) * | 2011-11-18 | 2012-05-09 | 华东电力试验研究院有限公司 | Current sampling circuit and current range judging device thereof |
| CN102445587B (en) * | 2011-11-18 | 2017-07-11 | 华东电力试验研究院有限公司 | Current sampling circuit and its current range determination device |
| CN104062487A (en) * | 2013-03-20 | 2014-09-24 | 鸿富锦精密工业(武汉)有限公司 | Voltage detection system |
| CN104062487B (en) * | 2013-03-20 | 2016-08-24 | 国家电网公司 | Voltage detecting system |
| CN104076190A (en) * | 2013-03-29 | 2014-10-01 | 海洋王（东莞）照明科技有限公司 | Direct current detection circuit |
| CN104076188A (en) * | 2013-03-29 | 2014-10-01 | 海洋王（东莞）照明科技有限公司 | Alternating current detection circuit |
| CN104779958A (en) * | 2014-01-10 | 2015-07-15 | 亚德诺半导体集团 | Amplifying system |
| CN104779958B (en) * | 2014-01-10 | 2018-06-22 | 亚德诺半导体集团 | amplification system |
| CN110794328A (en) * | 2019-10-30 | 2020-02-14 | 汉中一零一航空电子设备有限公司 | Detection circuit and detection method for detecting overload or short-circuit fault |
| CN114624492A (en) * | 2022-04-22 | 2022-06-14 | 西南交通大学 | Method for measuring potential difference of two remote transformer substation ground grids caused by direct current |
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Legal Events
| Date | Code | Title | Description |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| AV01 | Patent right actively abandoned | ||
| AV01 | Patent right actively abandoned |
Granted publication date: 20120711 Effective date of abandoning: 20170711 |