CN102928706A - Alternating current acquisition device and data acquisition method thereof - Google Patents
Alternating current acquisition device and data acquisition method thereof Download PDFInfo
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- CN102928706A CN102928706A CN2012104235647A CN201210423564A CN102928706A CN 102928706 A CN102928706 A CN 102928706A CN 2012104235647 A CN2012104235647 A CN 2012104235647A CN 201210423564 A CN201210423564 A CN 201210423564A CN 102928706 A CN102928706 A CN 102928706A
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Abstract
The invention discloses an alternating current acquisition device and a data acquisition method thereof. The alternating current acquisition device comprises a DSP (digital signal processor) processor and a singlechip which is connected with the DSP, wherein after being subjected to precision resistance voltage division, alternating current voltages of phase-A, phase-B and phase-C are boosted to voltage direct current signals with effective values of 0.7-1V from a reference voltage of 1.65V; the voltage direct current signals are processed into voltage values of 0-3.3V through an operational amplifier, and subsequently output to an analog/digital (A/D) conversion input port of the DSP processor; after passing through a current transformer, alternating currents of phase-A, phase-B and phase-C are boosted to small voltage direct current signals with effective values of 0.7-1V from the reference voltage of 1.65V; the small voltage direct current signals are processed into voltages of 0-3.3V through another operational amplifier and are subsequently output to the A/D conversion input port of the DSP processor; and at the same time, the small voltage direct current signals (with effective values of 0.7-1V) converted from the alternative voltages of phase-A, phase-B and phase-C are fed into a hysteresis comparator and output to a CAP port of the DSP. By utilizing the alternating current acquisition device and the data acquisition method, the requirement of the system on the precision can be met.
Description
Technical field
The present invention relates to the electric power data acquisition field, relate in particular to a kind of interchange harvester and collecting method thereof.
Background technology
In some industrial and mining enterprises, often need the monitoring parameters of electric power, in order to guarantee the quality of power supply, thereby guarantee product quality.At present, exchanging harvester mainly adopts 8 single-chip microcomputers or 16 s' DSP to design.Yet the single-chip data processing power is not enough, is difficult to obtain comprehensive parameters of electric power data; And in the existing system based on DSP, if signal-DSP system is selected expensive TMS320F28 family chip, then cost is higher; If select general TMS320F24 family chip, because speed is lower, function limitation; And adopt in TMS320F24 family chip and the system that 8 single-chip microcomputers are combined, all with single-chip microcomputer collection momentary current and voltage signal, only adopt dsp chip to finish the calculation of parameter task.And the acquisition precision of 8 single-chip microcomputers is not enough, just is difficult to guarantee the computational accuracy of alternating-current parameter.
Summary of the invention
The technical problem to be solved in the present invention is: a kind of interchange harvester and collecting method thereof are provided, in order to finish the Real-time Collection of alternating-current parameter, calculate in real time and show in real time, and satisfy the accuracy requirement of system.
To achieve these goals, the technical solution used in the present invention is: a kind of interchange harvester comprises voltage sample module, current sample module, frequency sampling module, dsp processor, single-chip microcomputer and display module; The voltage sample module is carried out voltage division processing by precision resistance to A phase, B phase and C alternating voltage mutually, is promoted to the voltage direct current signal by reference voltage again, and by after the amplifier processing, exports respectively the A/D conversion input port of dsp processor to; The current sample module, A phase, B phase and C alternating current mutually are converted to the voltage direct current signal by current transformer and reference voltage respectively, and by after the amplifier processing, export the A/D conversion input port of dsp processor to; The frequency sampling module with A phase or the C cross streams voltage voltage direct current signal by precision resistance and reference voltage conversion, is sent into hysteresis loop comparator, exports the CAP input port of dsp processor to again; Dsp processor is connected with single-chip microcomputer, and the single-chip microcomputer output terminal connects display module.
As preferably, described single-chip microcomputer adopts AT89S51.
As preferably, described dsp processor is TMS320F2407, and dsp processor and single-chip microcomputer pass through serial-port communication.
As preferably, described display module comprises charactron and button, and charactron is connected with single-chip microcomputer through the MAX7219 chip, and button is connected with the single-chip processor i/o mouth.
As preferably, described charactron is 8, and button is 2.
As preferably, described single-chip microcomputer is by 3 I/O mouths control MAX485 chips, thereby is mounted on 485 buses; Host computer turns 485 modules by 232 and is connected on 485 buses.
A kind of collecting method that exchanges harvester comprises dsp processor and connected single-chip microcomputer; A phase, B phase and C alternating voltage mutually are by after the precision resistance dividing potential drop, be promoted to again the voltage direct current signal of effective value 0.7～1V by the reference voltage of 1.65V, and be processed into the magnitude of voltage of 0～3.3V by amplifier after, export the A/D conversion input port of dsp processor to, calculated the instantaneous value of A phase, B phase and C cross streams piezoelectric voltage by dsp processor; A phase, B phase and C alternating current mutually are by behind the current transformer, be converted to again the voltage direct current signal of effective value 0.7～1V by the reference voltage of 1.65V, and be processed into the voltage of 0～3.3V by amplifier after, export the A/D conversion input port of dsp processor to, calculate the instantaneous value that A phase, B phase and C intersect galvanic current by dsp processor; With the voltage direct current signal of the effective value 0.7～1V of A phase or C cross streams voltage transitions, send into hysteresis loop comparator simultaneously, be processed into square wave after, export the CAP input port of dsp processor to, calculated the frequency of alternating current by dsp processor; Dsp processor passes to single-chip microcomputer with the parameter information that calculates, and single-chip microcomputer is finished the demonstration of alternating-current parameter by display module.
As preferably, described single-chip microcomputer is AT89S51, and dsp processor is TMS320F2407, and dsp processor and single-chip microcomputer pass through serial-port communication; Described display module comprises charactron and button, and charactron is connected with single-chip microcomputer through the MAX7219 chip, and button is connected with the single-chip processor i/o mouth; Described single-chip microcomputer is controlled the MAX485 chips by 3 I/O mouths, thereby is mounted on 485 buses; Host computer turns 485 modules by 232 and is connected on 485 buses.
As preferably, dsp processor gathers the instantaneous value of 64 voltage signals and current signal in each cycle, calculate three-phase voltage, three-phase current, frequency, active power, reactive power, applied power, power factor, active electrical degree, apparent electric degree, the harmonic parameters of three-phase alternating current, and be stored in the storer.
As preferably, the timer 0 of dsp processor interrupts being set as the 1s Interruption.
The beneficial effect that the present invention brings is: the present invention adopts the method for designing based on TMS320LF2407 and 8 single chip computer AT 89S51, take TMS32LF2407 as core, finishes collection and the calculating of AC signal; And only finish the demonstration of alternating-current parameter with single-chip microcomputer, thereby in the situation that guarantee the parameter acquisition precision, finish the Real-time Collection of alternating-current parameter, calculate in real time and show in real time.
Description of drawings
Fig. 1 is the circuit diagram of the embodiment of the invention.
Embodiment
The present invention is described in further detail below in conjunction with drawings and the specific embodiments.
Embodiment one
As shown in Figure 1, a kind of interchange harvester and collecting method thereof mainly comprise following part:
First: DSP microcontroller TMS320LF2407 gathers the C phase voltage frequency of alternating current:
Carry out dividing potential drop sampling by resistance R 29 (330K Ω) and R30 (1K Ω), wherein R30 is that precision is 1% metalfilmresistor, thereby (effective value≤300V) step-down obtains U with the C phase voltage of external communication electricity
Vc=300/331=0.91V (with respect to reference voltage 1.65V);
Be output as through amplifier:
(with respect to reference voltage 1.65V), by the lifting of 1.65V, effective value is that the AC signal of 300V is treated to the direct current signal with respect to the 0.28～3.02V on ground.
Above-mentioned signal is sent into the anti-phase hysteresis loop comparator that N7 and R35～R37 form, and the antijamming capability of hysteresis loop comparator is very strong, can improve measuring accuracy.
Hysteresis loop comparator has two threshold values.In this circuit, output voltage is changed to the threshold values of high level by low level, and output voltage is respectively by the threshold values that high level changes to high level:
The process of being calculated by the front voltage sampling circuit, Vc is 0.28～3.02V with respect to digitally magnitude of voltage as can be known, signal is the sinusoidal waveform of mean value 1.65V.And the reference voltage value of this hysteresis loop comparator normal phase input end is GNDA, i.e. 1.65V.By above calculating as can be known, two threshold values of hysteresis loop comparator depart from up and down about 0.15V centered by 1.65V, and the difference of two threshold values is 0.3V.Be disturbed when changing when input signal like this, as long as variable quantity is no more than 0.64V, it is stable that output quantity will keep, and the impact that can not be disturbed.
Above signal is input to the CAP1 end of TMS320LF2407, can calculate the frequency of signal.
Second portion: DSP microcontroller TMS320LF2407 gathers A, B and the C phase voltage of alternating current:
Carry out dividing potential drop sampling by resistance R 29 (330K Ω) and R30 (1K Ω), wherein R30 is that precision is 1% metalfilmresistor, thereby (effective value≤300V) step-down obtains U with the C phase voltage of external communication electricity
Vc=300/331=0.91V (with respect to reference voltage 1.65V);
Be output as through amplifier:
(with respect to reference voltage 1.65V), by the lifting of 1.65V, effective value is that the AC signal of 300V is treated to the direct current signal with respect to the 0.28～3.02V on ground;
Above signal enters the A/D input port ADCIN5 pin of dsp chip TMS320LF2407 behind capacitance-resistance (R34 and C6) filtering and stabilivolt (D6) amplitude limit;
The A/D of TMS320LF2407 inside is 10 one by one pattern number converters relatively, when select+during the accurate reference power supply of 3.3V, its quantization unit q is 3.22mV(3.3/1024=3.22mV), quantization error is q/2=1.61mV.In a wave period, analog-to-digital precision is 1.61 * 10 during DSP sampling minimum value 0.63 V
-3/ 0.28=0.57%, analog-to-digital precision is 1.61 * 10 during sampling maximal value 4.37V
-3/ 3.02=0.053%, in the parameter calculation formulas such as electric current, voltage effective value, every point sampling value is in equal status, but role is different.Be worth greatlyr, role is larger, and the precision of parameter is also mainly decided by large value.Therefore, can think that the precision of parameter is better than the mean value of minimum and maximum precision.Be that precision is better than 0.311%.
In like manner the A phase voltage of external communication electricity and B phase voltage connect respectively A/D input port ADCIN3 and the ADCIN4 pin of dsp chip TMS320LF2407 by similar processing.
Third part: DSP microcontroller TMS320LF2407 gathers A, B and the C phase current of alternating current:
By current transformer, with the C phase current signal (effective value≤5A) through accurate current transformer (precision is 0.1%, 5mA) and R24 (150 Ω) be converted to the small voltage signal, the size of small voltage signal effective value is: 5 * 10
-3* 150=0.75V, scope is ± 5 * 10
-3* 150 *
=± 1.06V (relative voltage benchmark 1.65V) relatively is 0.59～2.71V;
The emitter follower output that above-mentioned signal forms through amplifier;
Above-mentioned signal enters the A/D input port ADCIN2 pin of dsp chip TMS320LF2407 behind capacitance-resistance (R28 and C5) filtering and stabilivolt (D5) amplitude limit;
In a wave period, analog-to-digital precision is 0.161 * 10 during DSP sampling minimum value 0.59V
-3/ 0.59=0.274%;
Analog-to-digital precision is 0.161 * 10 during sampling maximal value 2.71V
-3/ 2.71=0.058%.The precision of the parameter of surveying should be better than 0.166%;
In like manner the A phase current of external communication electricity and B phase current connect respectively A/D input port ADCIN0 and the ADCIN1 pin of dsp chip TMS320LF2407 by similar processing.
The 4th part: the various parameter informations that DSP microcontroller TMS320LF2407 will calculate pass to the AT89S51 single-chip microcomputer.
DSP determines the sample frequency of electric current, voltage channel according to the frequency that records.For example suppose that frequency is 50Hz, then the cycle is 20ms.Per cycle of monitor gathers 64 points, and A/D channel sample frequency is 3200Hz, and the sampling period is 312.5us;
After TMS320LF2407 has gathered the one-period data, calculate all relevant parameters of electric power;
TMS320LF2407 is sent to the AT89S51 single-chip microcomputer with the mean value of institute's calculating parameter in the 1s Interruption;
After the AT89S51 single-chip microcomputer receives parameter, be stored in the storer, and by 3 I/O mouths, the SPI-bus analogue sequential drives the MAX7219 chip, thereby lights 8 charactrons, shows A phase voltage and current effective value;
The AT89S51 single-chip microcomputer has been expanded 2 buttons by 5 I/O mouths, is respectively upturning key and downturning key, and the user can select all the other parameters to show by upturning key and downturning key;
The AT89S51 single-chip microcomputer utilizes 3 I/O mouths, by the light lotus root, drives the MAX485 chip, has expanded a RS-485 interface, is mounted on 485 buses; Host computer turns 485 modules by 232, is mounted to 485 buses, can control nearly 255 interchange harvesters; Each exchanges harvester the unique address of oneself, and host computer can exchange collector to each and send the collection signal order, and this interchange harvester can be sent to host computer with parameters of electric power.
In order to guarantee the calculation of parameter precision, each cycle need to gather 64 points, and system just can calculate the cycle that dsp processor gathers three road voltage signals and three road current signals according to the frequency of the alternating current that calculates; 64 voltage signals that dsp processor TMS320F2407 collected according to each cycle and the instantaneous value of current signal, calculate the parameter such as three-phase voltage, three-phase current, frequency, active power, reactive power, applied power, power factor, active electrical degree, apparent electric degree, harmonic wave of three-phase alternating current, and be stored in the storer.
Embodiment two
That in the first, DSP microcontroller TMS320LF2407 gathers the A phase voltage frequency of alternating current, gathers identical with embodiment one with computation process with embodiment one difference; Second and third, four parts are with embodiment one.
Claims (10)
1. an interchange harvester is characterized in that: comprise voltage sample module, current sample module, frequency sampling module, dsp processor, single-chip microcomputer and display module;
The voltage sample module is carried out voltage division processing by precision resistance to A phase, B phase and C alternating voltage mutually, is promoted to the voltage direct current signal by reference voltage again, and by after the amplifier processing, exports respectively the A/D conversion input port of dsp processor to;
The current sample module, A phase, B phase and C alternating current mutually are converted to the voltage direct current signal by current transformer and reference voltage respectively, and by after the amplifier processing, export the A/D conversion input port of dsp processor to;
The frequency sampling module with A phase or the C cross streams voltage voltage direct current signal by precision resistance and reference voltage conversion, is sent into hysteresis loop comparator, exports the CAP input port of dsp processor to again;
Dsp processor is connected with single-chip microcomputer, and the single-chip microcomputer output terminal connects display module.
2. a kind of interchange harvester according to claim 1 is characterized in that: described single-chip microcomputer employing AT89S51.
3. a kind of interchange harvester according to claim 2, it is characterized in that: described dsp processor is TMS320F2407, and dsp processor and single-chip microcomputer pass through serial-port communication.
4. a kind of interchange harvester according to claim 3, it is characterized in that: described display module comprises charactron and button, and charactron is connected with single-chip microcomputer through the MAX7219 chip, and button is connected with the single-chip processor i/o mouth.
5. a kind of interchange harvester according to claim 4, it is characterized in that: described charactron is 8, button is 2.
6. a kind of interchange harvester according to claim 5 is characterized in that: described single-chip microcomputer is by 3 I/O mouths control MAX485 chips, thereby is mounted on 485 buses; Host computer turns 485 modules by 232 and is connected on 485 buses.
7. a collecting method that exchanges harvester is characterized in that: comprise dsp processor and connected single-chip microcomputer; A phase, B phase and C alternating voltage mutually are by after the precision resistance dividing potential drop, be promoted to again the voltage direct current signal of effective value 0.7～1V by the reference voltage of 1.65V, and be processed into the magnitude of voltage of 0～3.3V by amplifier after, export the A/D conversion input port of dsp processor to, calculated the instantaneous value of A phase, B phase and C cross streams piezoelectric voltage by dsp processor; A phase, B phase and C alternating current mutually are by behind the current transformer, be converted to again the voltage direct current signal of effective value 0.7～1V by the reference voltage of 1.65V, and be processed into the voltage of 0～3.3V by amplifier after, export the A/D conversion input port of dsp processor to, calculate the instantaneous value that A phase, B phase and C intersect galvanic current by dsp processor; With the voltage direct current signal of the effective value 0.7～1V of A phase or C cross streams voltage transitions, send into hysteresis loop comparator simultaneously, be processed into square wave after, export the CAP input port of dsp processor to, calculated the frequency of alternating current by dsp processor; Dsp processor passes to single-chip microcomputer with the parameter information that calculates, and single-chip microcomputer is finished the demonstration of alternating-current parameter by display module.
8. a kind of collecting method that exchanges harvester according to claim 7, it is characterized in that: described single-chip microcomputer is AT89S51, and dsp processor is TMS320F2407, and dsp processor and single-chip microcomputer pass through serial-port communication; Described display module comprises charactron and button, and charactron is connected with single-chip microcomputer through the MAX7219 chip, and button is connected with the single-chip processor i/o mouth; Described single-chip microcomputer is controlled the MAX485 chips by 3 I/O mouths, thereby is mounted on 485 buses; Host computer turns 485 modules by 232 and is connected on 485 buses.
9. a kind of collecting method that exchanges harvester according to claim 8, it is characterized in that: dsp processor gathers the instantaneous value of 64 voltage signals and current signal in each cycle, calculate three-phase voltage, three-phase current, frequency, active power, reactive power, applied power, power factor, active electrical degree, apparent electric degree, the harmonic parameters of three-phase alternating current, and be stored in the storer.
10. a kind of collecting method that exchanges harvester according to claim 9 is characterized in that: the timer 0 of dsp processor interrupts being set as the 1s Interruption.
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| CN103197136A (en) * | 2013-04-25 | 2013-07-10 | 天津市百利电气有限公司 | Ampere meter for air-core transformer and control method thereof |
| CN110333384A (en) * | 2019-08-15 | 2019-10-15 | 杭州电子科技大学 | Three-phase alternating voltage high-precision quick detection circuit based on mutual inductor |
| CN111381536A (en) * | 2020-03-05 | 2020-07-07 | 九江学院 | TMS320F28 series DSP excitation acquisition system |
| CN116298492A (en) * | 2023-05-23 | 2023-06-23 | 山东棋盘信息科技有限公司 | Alternating current mixed signal detection system and method |
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Cited By (6)
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| CN103197136A (en) * | 2013-04-25 | 2013-07-10 | 天津市百利电气有限公司 | Ampere meter for air-core transformer and control method thereof |
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| CN116298492A (en) * | 2023-05-23 | 2023-06-23 | 山东棋盘信息科技有限公司 | Alternating current mixed signal detection system and method |
| CN116298492B (en) * | 2023-05-23 | 2023-08-22 | 山东棋盘信息科技有限公司 | Alternating current mixed signal detection system and method |
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