CN1030669C

CN1030669C - Digital three-phase wattmeter

Info

Publication number: CN1030669C
Application number: CN 93100287
Authority: CN
Inventors: 卢纪畅
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-01-21
Filing date: 1993-01-21
Publication date: 1996-01-10
Anticipated expiration: 2013-01-21
Also published as: CN1090393A

Abstract

The present invention relates to a three-phase multifunctional digit wattmeter, which can save electric power energy sources and monitor electric power use. The digit wattmeter is composed of a display driving circuit, a key scanning circuit, a digit circuit, an analogy circuit, a relay output circuit, a current comparator output circuit and a voltage comparator output circuit. The digit wattmeter has the functions of multiple terms of data display, upper limit and lower limit alarm setting, contract capacity reduction and electric power cost reduction through the combination of circuits; meanwhile, the digit wattmeter is provided with analogy signal output which can be connected with a recorder and is also provided with a static random access memory body CMOSSRAM which can cause data input to be completely protected.

Description

Three-phase multifunctional digital power table

The present invention relates to a kind of industrial three-phase power table, relate to a kind ofly to replace traditional three-phase kilowatt-hour meter and electric power converter or rather, with the three-phase digital power table of the various electric power datas of digital form centralized displaying.

Present electric power transfer all adopts the three-phase system system and uses thinner lead for reducing the economy of IR loss and consideration electric power transfer.Then efficient is higher if interchange become direct current and increase the number of phases, and the number of phases the more, more ideal and the generation of three-phase power promptly increase the coil groups number and turn to specific pattern and promptly constitute multiphase generator on generator amature in direct current output.

Basic electric weight instrument, the ohm that comprises the ammeter of measuring electric current, the voltmeter of measuring voltage, the wattmeter of measuring power, measuring resistance is taken into account resistance bridge, the basic building block (move ment) that gauging instrument uses has Da Songfaer (D ' Arsonval), iron wing formula (Iron-Vanetype) and electronic dynamometer (Electrodynamometer), wherein any all can be used for the d-c/a-c ammeter, in d-c/a-c voltmeter, ohmmeter and the resistance bridge, and only can use electronic dynamometer formula member in the wattmeter.Described basic building block is made of bearing, permanent magnet, iron-core coil and volute spring, by the iron-core coil between bearing support permanent magnet, but the volute spring limiting coil rotates, electric current passes through coil through volute spring, because the interaction of coil and magnet magnetic flux, make coil produce a torque and rotate, read tested electric weight with pointer again.This is the metering method of electric weight instrument widespread usage commonly used, but this pointer structure is subjected to miscellaneous factor affecting easily and produces error and load effect.

The objective of the invention is to design a kind of industrial three-phase multifunctional digital power table, to replace the complicated three-phase electricity measuring appratus of tradition, the various electric quantity datas that record are shown with digital form, comprise three-phase voltage, three-phase current, real power, look power, fictitious power, frequency, power factor, hour leading, backwardness, relay output state, time delay, leakage current etc., calculate reducing error with digital computation in conjunction with simulation increases instrument function and reduces cost, with employing RS-232 serial line interface or RS-422 interface, be convenient to computing machine and make to concentrate power monitoring.

Three-phase multifunctional digital power table of the present invention, by three-phase voltage sampling thief, three-phase current sampling thief, multiplier, totalizer, electric current and voltage effective value converter, analog-to-digital conversion circuit, the electric current and voltage phase place is leading or fall behind testing circuit, microprocessing unit, voltage/frequency meter, display, keyboard circuit, random memory, buzzer drive circuit, computer output interface circuit, D/A conversion circuit, simulate output unit and the relay output unit constitutes, it is characterized in that:

Three-phase voltage V1, V2, V3 and three-phase current A1, A2, A3 imports three-phase voltage sampling thief and three-phase current sampling thief respectively, the output of three-phase voltage sampling thief and three-phase current sampling thief connects multiplier respectively, electric current and voltage effective value converter, leading or backward testing circuit of electric current and voltage phase place and voltage/frequency meter, multiplier output three phase power send totalizer, the totalizer of output three-phase general power and the output that the honeybee of input to the electric current and voltage of peak value converts the electric current and voltage effective value converter of effective value to connect analog to digital conversion circuit, leading or the backward testing circuit of electric current and voltage phase place of voltage and current and phase difference is exported and detected to analog to digital conversion circuit, microprocessing unit I/O is sent in the output of voltage/frequency meter end respectively, the I/O end of microprocessing unit also connects display respectively, keyboard circuit, random access device, buzzer drive circuit, the relay output unit, D/A conversion circuit and computer output interface circuit, described D/A conversion circuit output connects analogue output unit.

Dynamometer instrument of the present invention is done peripheral operation control by keyboard circuit, exportable whole three-phase power data also are presented on the display, all output data also can be stored in the static random memory, under the manipulation of microprocessing unit instruction, can send D/A conversion circuit with the data in the memory, export by analogue output unit, the analog quantity of output can be sent register, also the interface circuit of machine output is served the one-level computer with memory data and is done the Centralized Monitoring management as calculated, in addition, dynamometer instrument interrupts or error signal to external control switch output, then makes concrete executable operations by buzzer drive circuit and relay output unit respectively.

Described display is by the 4-16 code translator, three eight bit data latchs, 48 are total to anode display tube and 16 transistors compositions, the code translator input end connects described microprocessing unit I/O end, 48 are total to the anode display tube and are divided into three groups, the collector that each is organized the common anode order correspondence of display tube and connects and connect respectively 16 transistors, the base stage of 16 transistors connects the output terminal of code translator respectively, the emitter of 16 transistors connects+the 5V power supply, the data bus of the input termination microprocessing unit of three eight bit data latchs, the output terminal of three eight bit data latchs connect the eight sections negative electrodes of a-h that are total to the anode display tube in each group respectively.

The effect of data latches is the locking video data, makes to continue to light display tube in scanning.

Further specify technology of the present invention below in conjunction with the embodiment accompanying drawing

Fig. 1, three-phase multifunctional digital power off-balancesheet are seen stereographic map

Fig. 2, three-phase multifunctional digital power table internal plane

Fig. 3, three-phase multifunctional digital power table gauge outfit stereographic map

Fig. 4, three-phase multifunctional digital power table frame principle figure

Fig. 5, Fig. 6 are display and the equal scanning circuit figure of button among Fig. 4

Fig. 7 is a numerical portion circuit diagram among Fig. 4

Fig. 8 is simulation partial circuit figure among Fig. 4

Fig. 9 is electric current and voltage effective value change-over circuit among Fig. 4, computer output interface circuit, reference voltage circuit and voltage/frequency meter circuit diagram

Figure 10 is the output of Fig. 4 repeat circuit, current sample, voltage sampling circuit figure

Referring to Fig. 1 to Fig. 3, three-phase multifunctional digital power off-balancesheet shape of the present invention is box, casing 101 is provided with gauge outfit 102, many groups anode eight n segment display ns (LED) 103 are altogether arranged on the dial plate 104 of gauge outfit 102, be used to show various current/voltage values or its ratio value, as look power KVA, real power KW, three-phase current A, active electrical degree is counted KWH, three-phase voltage V, fictitious power KVAR, frequency HZ, power factor PF and fictitious power electric degree are counted KVARH etc., reading comes into plain view, simultaneously output state, the time delay of dynamometer instrument, multinomial data such as leakage current also can show.

Referring to Fig. 4, Fig. 4 illustrates the functional part structure and the signal annexation thereof of three-phase multifunctional digital power table.Three-phase voltage V1, V2, V3 and three-phase current A1, A2, A3 import three-phase voltage sampling thief 201 and three-phase current sampling thief 202 respectively, import multiplier 203, electric current and voltage effective value converter 207 more respectively, the electric current and voltage phase place is leading or falls behind testing circuit 208 and voltage/frequency meter 209.Multiplier 203 is tried to achieve three phase power Wn=VnAn; Effective value converter 207 will be imported honeybee to the voltage of peak value VP-P and current conversion and become effective value RMS output; Phase place falls behind the phase differential that testing circuit 208 detects voltage and electric current in advance; 209 outputs of voltage/frequency meter, supply frequency variable.Wherein multiplier 203 is with the three phase power W1 that calculates, W2, W3 sends totalizer 204 to, the totalizer three-phase general power W that sues for peace out, the three-phase voltage current effective values that three-phase general power W reaches by 207 outputs send analog to digital conversion circuit 205, general power and three-phase voltage current effective value data-signal after the A/D conversion send microprocessor unit 206, the backward in advance testing circuit 208 of phase place also send microprocessing unit 206 with the data-signal of voltage/frequency meter 209 outputs simultaneously, operating keyboard circuit 216 just can be shown in whole three-phase power data outputs on the display 210.

All output datas all can be stored in the static random memory 217, this stored data can be imported digital-to-analogue D/A change-over circuit 212 under the instruction of microprocessing unit 206 is handled, and by analogue output unit 213 outputs, stored data also can be transferred to computer by a computer output interface 211 (as RS-232) and do the Centralized Monitoring management.Dynamometer instrument output look-at-me or error signal are respectively by buzzer drive circuit 215 and relay output unit 214 control external switches.

Referring to Fig. 5, Fig. 6, integrated JP2, diode D1-D5, switch S 1-S5 etc. constitute key circuit.4-16 code translator IC1 (74LS159), data latches IC2-IC4 (74LS373), 48 are total to

anode display

1 and 2,16 current-limiting resistances of 16 transistors, 3 formation multiplex (MUX) reading scan circuit.48 altogether the anode display tubes be divided into three groups, every group of 16 display tube U1-U16, U17-U32, U33-U48.The anode of U1, U17, U33 is the collector by resistance R 1, R17, R33 and triode Q1 and connecing respectively, the anode of U2, U18, U34 is the collector by resistance R 2, R18, R33 and triode Q2 and connecing respectively ..., and the like until the anode of U16, U32, U48 the collector by resistance R 16, R32, R48 and triode Q16 and connecing respectively.The emitter of 16 transistors 2 meets positive supply 5V, IC1 end pin YO-Y15 connects the base stage of transistor Q1-Q16 respectively through current-limiting resistance R49-R64,2,5,6,9,12,15,16, the 19 end pin of IC2-IC4 are total to anode display U1-U16, U17-U32 with three groups respectively, eight sections negative electrode a-h, a1-h1 of U33-U48, a2-h2 connect, the video data locking that data latches IC2-IC4 sends microprocessor here makes the display tube in the scanning continue to light.

Referring to Fig. 7, digital circuit part for three-phase multifunctional digital power table, comprise microprocessor U17 (8751), random access memory (RAM) 4 (A), reset circuit 5 (B), buzzer drive circuit 6 (C), relay drive circuit 7 (D), D/A converting circuit 8 (E), analog to digital conversion circuit 9 (F) and mu balanced circuit 10 (G).

3,4,7,8,13,14,17, the 18 end pin of the P0.0-P0.7 of U17 end pin map interlinking 51C2-IC4 make that display tube continues to light in the scanning.U17 also scans button S1-S5, S9, S10, S13-S15 simultaneously, and scans back 5 keys by diode D1-D5, is read by the 14 pin TO of U17.

Storaging chip U14 (6116) is the complementary metal oxide semiconductor (CMOS) device, is used to store the data from microprocessor U17 or extraneous input.Analog signal conversion such as the three-phase voltage that analog to digital conversion circuit 9 will be detected by eight passage INO-IN7, electric current, general power are the receivable digital signal of microprocessor U17, microprocessor U17 can drive the break-make of relay circuit 7 repeat circuits, when making a mistake, U17 drives buzzer drive circuit 6.The frequency of operation of hummer is produced by the microprocessor interrupt routine, and D/A converting circuit 8 will convert simulating signal to through the digital signal that U17 handles, and this number is touched the D/A circuit a delivery outlet, can be connected with register or PLC.Mu balanced circuit 10 partly provides working power for above-mentioned digital circuit, and the power supply of digital circuit power supply partly with artificial circuit part separated, and is to disturb for anti-stop signal.

Referring to Fig. 8, be the artificial circuit part of three-phase multifunctional digital power table, comprise multiplication totalizer 11 (A), simulating signal output circuit 12 (B), leading, the backward decision circuitry 13 (C) of phase place and analog output signal driving circuit 14 (D).

Wherein multiplier 11 is used to calculate three phase electric power, with the addition again of multiplying each other of magnitude of voltage (PT1, PT2, PT3) and current value (CT1, CT2, CT3), and result of calculation is sent the analog to digital conversion circuit 9 of Fig. 7 through simulating signal output circuit 12.Microprocessor U17 calculates KVA, KVAR, KW, KVARH, PF, KWH equivalence according to three-phase voltage, current value and total power value etc.

Leading, the backward decision circuitry 13 of phase place is used to judge the phase differential between voltage, electric current, judges according to the multiplied result of multiplier, if just promptly fall behind; If it is negative promptly leading.Simulating signal output driving circuit 14 is exported the signal boost of simulating signal output circuit 12 to 4-20MA.

Referring to Fig. 9, mainly include effect value change-over circuit 15 (A), RS-232 interface 16 (B), reference voltage circuit 17 (C) and voltage/frequency meter 18 (D).

The PPT1 of effective value change-over circuit 15, PPT2, PPT3, CT1, CT2, CT3 are connected with end of the same name in Fig. 8 multiplier 11 respectively in the tool, provide for the effective value that calculates to multiplier.RS-232 interface 16 provides the conversion of signals that is connected with computer.Reference voltage circuit 17 provides one to be used for the basic analog references amount REF2 that changes to analog to digital conversion circuit.Voltage/frequency counting circuit 18 is used for providing the negative sense reference data to D/A converting circuit.Make and change out definite value preferably.

Referring to Figure 10, comprise relay output circuit 20 (B) and voltage, current sample input circuit 19 (A), relay output circuit 20 is connected with Fig. 7 repeat circuit driving circuit 7.And voltage, current sample input circuit 19 are connected with multiplier 11 among Fig. 8.

Advantage of the present invention is can show multinomial electric power data and make the upper and lower limit alarm setting, can reduce Cost, but set analog signal output linkage record device, set memory SRAM can The electric power data that complete preservation is relevant.

Claims

1, a kind of three-phase multifunctional digital power table, by three-phase voltage sampling thief, three-phase current sampling thief, multiplier, totalizer, electric current and voltage effective value converter, analog-to-digital conversion circuit, the electric current and voltage phase place is leading or fall behind testing circuit, microprocessing unit, voltage/frequency meter, display, keyboard circuit, random memory, buzzer drive circuit, computer output interface circuit, D/A conversion circuit, simulate output unit and the relay output unit constitutes, it is characterized in that:

2, three-phase multifunctional digital power table according to claim 1, it is characterized in that: described display is by the 4-16 code translator, three eight bit data latchs, 48 are total to anode display tube and 16 transistors compositions, the code translator input end connects described microprocessing unit I/O end, 48 are total to the anode display tube and are divided into three groups, the collector that each is organized the common anode order correspondence of display tube and connects and connect respectively 16 transistors, the base stage of 16 transistors connects the output terminal of code translator respectively, the emitter of 16 transistors connects+the 5V power supply, the data bus of the input termination microprocessing unit of three eight bit data latchs, the output terminal of three eight bit data latchs connect the eight sections negative electrodes of a-h that are total to the anode display tube in each group respectively.