CN2172477Y - Integral electronic watt-hour meter - Google Patents

Abstract

The utility model relates to an integral electronic watt-hour meter, comprising an outer case and an electrical source. The outer case is provided with a plurality of sub-meters and a main meter. The sub-meters comprise an over-current joint, a current commutation part and a display unit. The main meter comprises a voltage commutation part, an analog switch, an analogue-to-digital converter, a transact-control unit, a memorizer and a joint (a display drive circuit). The current passing through each sub-meter is transferred to the main meter after conversion. The information of electricity usage of each circuit is counted and controlled by an SCM to connect to the display units of the sub-meters via a joint circuit. The utility model has the advantages of integral structure, high precision, low energy consumption, easy management and being easy to enlarge the function.

Description

Integral electronic watt-hour meter

The utility model relates to measurement, the measuring instrument that a kind of power department is used, particularly a kind of centralized electronic electric meter.

Watt-hour meter is an important measurement instrument of getting in touch between power department and the power consumer.Its performance quality can directly have influence on power department and power consumer.The a large amount of at present induction type mechanical watt-hour meters that adopt of China, it is to reach the purpose of measuring electric energy by produce alternating magnetic field in ammeter.Potential winding adds voltage in ammeter, when current coil flow through electric current, along with the change of size of current, the alternating magnetic field of generation was strong and weak different, make the eddy current that induces on the aluminium disk that is in the magnetic field along with change, make of the speed rotation of aluminium disk, pass to counter, realize the metering of electric energy by mechanical transmission method combining according to the rate that is directly proportional with power, this product power consumption is high, measuring accuracy is low, and applicability and anti-interference are poor, management inconvenience;

Domestic since 87 years, the scientific research personnel is constantly releasing various schemes aspect the remodeling of ammeter.The proposition that has utilizes the silicon controlled switching characteristic, and the break-make of control ammeter potential winding makes that potential winding did not consume energy when consumer electronics was not worked.Chip box is installed in the proposition that has additional on ammeter, make the user (for example: coin etc.), thereby pay dues after making first electricity consumption, become and buy electricity back electricity consumption earlier must drop into certain chip before electricity consumption.Single-chip microcomputer is installed in the proposition that has additional, carries out Based Intelligent Control, monitor user ' situation, count by time sharing balanced load or the like.

Domestic now existing several families plant produced goes out centralized watt-hour meter, it is idle according to mechanical type, the input pulse of active power pulse meter, in data processing unit, handle, calculate, write down, show, the subject matter that it exists is the structure more complicated, cost is also high, also can't overcome the many disadvantages that the induction table itself brings.

CN-2048590 has proposed a kind of digital watt-hour meter of intelligent card style, voltage wherein, current signal are by the pulse of multiplier and V-F circuit active power of output, link to each other with close card circuit through CPU element again, this watt-hour meter can only detect active power, function singleness, according to present scientific and technological level, at a low price the temperature of multiplier float with precision all difficulty satisfy the demand, and the confidentiality of close card is also very poor.

CN-86100655 discloses a kind of intelligent multi-function power meter, it is sent into an A/D conversion chip to voltage, current signal and changes digital quantity into and isolate through photoelectricity and send into CPU and calculate, control, show, this table adopts the method for discrete calculation to calculate meritorious, reactive power, but owing to only adopt an A/D conversion chip, detected voltage and current signal is not with moment signal, certainly exists error after calculating; In addition, it is also very high to satisfy the price of A/D chip of certain accuracy requirement.

Continuous expansion along with city-building, the high-rise apartment building dwelling house has become the principal mode of big and medium-sized cities house, and the power consumption of household electrical appliance increases day by day, reaching contradictions such as power supply mode, clearing form between the electricity consumption supply and demand enlarges day by day, original induction meter more and more can not meet the demands, after the system of carrying out particularly that Every household has an ammeter, the installing space on the self-contained flat metope and copy, the contradiction of calibration workload is very outstanding.

The purpose of this utility model is to overcome the deficiencies in the prior art and provides a kind of overload capacity strong, oneself power consumption is low, the measuring accuracy height, structure is concentrated, cheap, the centralized electronic electric meter of daily Maintenance free, further can have count by time sharing and promptly answer the rate function, and can calculate, record, show or transmit the voltage of each power consumer, electric current, power factor (PF), the active energy of peak/flat/paddy (can have more multi-period), reactive energy, active power, reactive power, requirement, frequency, it is initial to cut off the power supply, power supply situation when finish-time and outage, the super situation of holding electricity consumption and low-power factor.

Centralized electronic electric meter of the present utility model comprises assembles the shell of taking circuit board in, and power supply is characterized in that being equipped with in the shell a plurality of submeters and a master meter;

Submeter wherein comprises the interface of overcurrent; The current transformation part is used to the electric current corresponding voltage signal of sending and importing; Display device;

Master meter wherein is by forming with the lower part:

The voltage transformation part is used to send and the corresponding low-voltage signal of added high voltage;

Analog switch is used for the current transformation of a plurality of submeters is partly transmitted the voltage signal conducting electedly of the reflection size of current of coming;

Analog to digital converter is used for above-mentioned voltage transformation part is become digital signal with the conversion of signals that current transformation is partly imported;

Processing and control element (PCE);

Storer comprises program storage, data-carrier store;

Input/output interface circuit comprises display driver circuit, transmission circuit, test port;

The electric current that each road submeter flows through is partly sent into analog switch in the master meter through current transformation, analog switch connection mode number converter, digital signal after conversion is sent into processing and control element (PCE), storer, input/output interface circuit are connected with processing and control element (PCE), the power information on each road be current value by with processing and control element (PCE) be that the voltage parameter of single-chip microcomputer collection calculates, be connected to the display device of submeter again through input/output interface circuit by the control of single-chip microcomputer.

Centralized electronic electric meter of the present utility model has been realized all-electronic measurement, calculating, storage, demonstration, printing, transmission, adopted the technology of alternating voltage, electric current directly being carried out synchronous random sampling technique and centralized management, so this table has following characteristics:

1, structure is concentrated, simple, and the erection space that accounts for is little.

2, record or data quantity transmitted are big, can write down, show or transmit required various parameters of electric power selectively, these parameters are voltage, electric current, power factor (PF), active energy, the reactive energy of peak/flat/paddy (can have more multi-period), active power, reactive power, requirement, frequency, power supply situation when cutting off the power supply initial, finish-time and outage, the super situation of holding electricity consumption and low-power factor also can show date, Hour Minute Second.

3, Ben Biao can handle the electric power signal of higher hamonic wave, thereby the metering precision height.

4, can store each user's of many months electricity consumption situation.

5, automatic zero set (AZS), the function of calibration are automatically arranged.

6, big superpotential, current capacity are arranged, can carry out range automatically and switch.

7, energy subregion, timesharing, branch valency automatic charging can write down the situation that surpasses appearance and low-power factor, make power department come re-set price by the disparities between supply and demand of this specialty goods that can not store of electric power, finally realize peak load shifting as far as possible.

8, can utilize the peek device of serial port and host computer or palmtop computer or similar palmtop computer to carry out communication, realize the electric-power metering data that preset, revise and extract all storages of parameter, also can utilize mini-printer directly to print the electricity consumption form.

9, power consumptive province belongs to energy-saving product, and saves non-ferrous metal.

10, expanded function is easy, further develops new varieties such as wireless telemetering.

For introducing the utility model in detail, followingly in conjunction with the accompanying drawings its circuit theory and technical characterictic are further described:

Fig. 1 is a schematic block circuit diagram of the present utility model;

Fig. 2 is the schematic block circuit diagram of another embodiment of similar Fig. 1;

Fig. 3 is the schematic block circuit diagram of another embodiment of similar Fig. 1;

Fig. 4 is the detailed wiring diagram of voltage transformation part;

Fig. 5 is one tunnel current transformation detailed wiring diagram partly;

Fig. 6 is the signal processing circuit before the analog to digital conversion circuit;

Fig. 7 is the electrical schematic diagram of similar Fig. 7 function;

Fig. 8 is the electrical schematic diagram of another similar Fig. 7 function;

Fig. 9 is the wiring diagram of centralized watt-hour meter of the present utility model.

Referring to Fig. 1,2,3,9, centralized electronic electric meter of the present utility model comprises and assembles the shell of taking circuit board in that power supply (not showing on the figure) is characterized in that being equipped with in the shell a plurality of submeters 100 and a master meter 200; Power unit wherein is responsible for the power supply to whole circuit of master meter and submeter.

Submeter 100 wherein comprises the interface of overcurrent, joins with the zero line row in the electric system; Current transformation part 101 is used to the electric current corresponding voltage signal sending and import, and Fig. 5 has provided the circuit diagram of one of them embodiment, also can adopt the power pack of various circuit theories of the prior art; Do not show among display device 102(Fig. 1,2,3), comprise stepper motor and character wheel, also can adopt display device of the prior art such as charactron; Trigger is adopted in the driving of general stepper motor, and this trigger can be contained in the submeter or be contained on the master meter certainly;

Master meter 200 wherein is by forming with the lower part:

Voltage transformation part 201 is used to send and the corresponding low-voltage signal of added high voltage, is used to send and the corresponding low-voltage signal of added high voltage (for example 220V), be generally ± 5V, provided a specific embodiment among Fig. 4, wherein adopted divider resistance R11, the R12 dividing potential drop, also comprise filter capacitor C11, clamper stabilivolt DZ11, DZ12, the operational amplifier IC11 that high precision, low temperature float forms, amplifier wherein is connected into the emitter follower mode, carries out impedance matching;

Analog switch 202, be used for the current transformation of a plurality of submeters is partly transmitted the voltage signal conducting electedly of the reflection size of current of coming, this conducting all under the control of the CPU of single-chip microcomputer, the number that how much depends on submeter of analog switch and the way of analog switch;

Analog to digital converter 203 is used for above-mentioned voltage transformation part is become digital signal with the conversion of signals that current transformation is partly imported, and in order to improve the measuring accuracy of wide-range, can be connected in series before analog to digital converter and go into a programmable amplifier;

Processing and control element (PCE) 204, it is a microprocessor, is preferably the single-chip microcomputer of various models;

Storer 205 comprises program storage (EPROM) 251, data-carrier store, for example static memory (SRAM) 252 and/or long-term nonvolatile storage device (EEPROM) 253;

Input/output interface circuit 206, comprise and deliver to the output circuit 261 that submeter shows usefulness,, serial communication transmission circuit 262, the various combinations of these parts and CPU belong to design general in the prior art, comprise necessary code translator, latch and parallel port expanded circuit 263; Also can comprise test port (not showing on the figure), and be the clock circuit 264 of the multiple rate scale design of count by time sharing, for example MSM5832;

The electric current that each road submeter flows through is partly sent into analog switch in the master meter through current transformation, analog switch connection mode number converter, digital signal after conversion is sent into processing and control element (PCE), storer, input/output interface circuit are connected with processing and control element (PCE), calculating and the control display device that through input/output interface circuit be connected to submeter of the power information on each road by processing and control element (PCE).

The trigger circuit that illustrate on the figure just produce a square-wave signal according to the frequency of voltage signal, are input to the hsi port of single-chip microcomputer, are used for calculating the sampling interval to voltage, current signal.

The circuit theory diagrams among Fig. 2 and the key distinction of the circuit theory diagrams among Fig. 1 are to be connected to a sampling holder 208 before analog to digital converter, sampling hold circuit is in order to guarantee that the voltage and current signal Vi, the Ii that sample are synchronous;

The circuit theory diagrams among Fig. 3 and the key distinction of the circuit theory diagrams among Fig. 1 are can connect a plurality of analog to digital converters for more submeter.

Saved a long-term nonvolatile storage device (EEPROM) among Fig. 1.

More than various schemes in three schematic diagrams can make up arbitrarily according to actual needs.

In order to reduce the cost of complete machine, can adopt inside to protect the single-chip microcomputer that becomes to have analog to digital converter, for example 8098,8096 etc., wherein 8098 is products that U.S. intel company released in 1988, have than other single-chip microcomputer performance height, function is complete, price is low, advantage easy to use, it has 6 RALU of a high-performance, high speed I/O port (HSI/HSO), have 4 tunnel 10 A/D that sampling keeps (S/H) circuit, a serial port, two 16 timer, a self-resetting circuit (WATCHDOG) only needs little hardware to support just can form a complete microcomputer, because the A/D in this sheet can only detect the signal of positive half cycle, before the A/D of signal in sending into single-chip microcomputer of sampling holder output, need carry out pre-service to signal, referring to Fig. 6,7, Signal Pretreatment shown in 8 or signal conversion circuit, the scheme of Fig. 6 is 4 road A/D that make full use of in the sheet, wherein two tunnel detections that are used for voltage signal, in addition two tunnel detections that are used for current signal, no matter be the signal of response voltage variation or the signal that kinetic current changes, signal for positive half cycle, by inserting the forward end of amplifier, output terminal from amplifier inserts A/D again, signal for negative half period, reverse by the backward end that inserts amplifier, the output terminal from amplifier inserts A/D again; The scheme of Fig. 7 is that the signal of first handle ± 5V is raised 5V by amplifier, isolates the signal of positive-negative half-cycle by two amplifiers; The scheme of Fig. 8 is to utilize the switching of analog switch to raise 5V not with an amplifier signal according to the situation that signal is in positive-negative half-cycle.Any above connection all broadening range, promptly 10 A/D is become 11.

A/D samples with voltage, electric current discrete value constantly in the sheet of this machine, just can calculate voltage, electric current, active power, reactive power, active energy, reactive energy B, and wherein the formula of Ji Suaning is as follows:

Magnitude of voltage V= $\sqrt{\frac{1}{N}\underset{i=1}{\overset{i=\mathrm{<figure-callout\; id="2"\; label="N\; Vi"\; filenames="932431887\_DRIMG2.png"\; state="\{\{state\}\}">N</figure-callout>}}{\mathrm{\&Sigma;}}}{\mathrm{Vi}}^{}{}^2}$

Current value I= $\sqrt{\frac{1}{N}\underset{i=1}{\overset{i=\mathrm{<figure-callout\; id="2"\; label="N\; Ii"\; filenames="932431887\_DRIMG2.png"\; state="\{\{state\}\}">N</figure-callout>}}{\mathrm{\&Sigma;}}}{\mathrm{Ii}}^{}{}^2}$

Active power P=1/ (N) $-\underset{i=1}{\overset{i=N}{\mathrm{\&Sigma;}}}\mathrm{Vi}/\mathrm{AIi}$

Reactive power Q= $\sqrt{{\mathrm{<figure-callout\; id="2"\; label="V"\; filenames="932431887\_DRIMG2.png"\; state="\{\{state\}\}">V</figure-callout>}}^2\&times;I^2-{\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="932431887\_DRIMG2.png"\; state="\{\{state\}\}">P</figure-callout>}}^2}$

Power factor (PF) COS φ=P/(V * I)

Active energy W=P * Δ T

Reactive energy A=Q * Δ T

Wherein * and Δ T is the time interval, N is the sampled point number.

Time (and date) in the time of can be according to detection and this moment residing peak/paddy/level state, write down the electricity consumption situation by the requirement of multiple rate respectively, simultaneously can calculate requirement, frequency, the record outage is initial, power supply situation when finish-time and outage, the super situation of holding electricity consumption and low-power factor, also can show the date, Hour Minute Second, above-mentioned total data or partial data can add up as required, refresh, store in the integral point moment or official hour, also can remember respectively to exist among SRAM or the EEPROM, can show in real time certainly according to data ermine importance, print, transmission.

The wherein setting of tariff period again, the super limit value that holds electricity consumption and low-power factor, parameters such as the metering time of requirement can preset by the serial port transmission, necessary toggle switch also can be set realize.

In order to reduce cost, particularly under situation with dozens of or hundreds of submeter, it is uneconomic adopting the power pack (for example current transformer) of isolating, can adopt the method on the same zero line that is connected in the electric system of the ground connection zero line of circuit in circuit in the master meter and the submeter, increase interference free performance.

The specific embodiments of the concentrated test of above-mentioned proposition, metering, storage, a plurality of submeters of management is not limited only to single-phase table, also can extend to the single-phase table of three-phase table or three phase supply on the basis of existing technology.

In order to improve the measuring accuracy of complete machine, except above mentioned employing low temperature floats the amplifier, also can be by selecting suitable single-chip microcomputer and circuit structure arrangement, other measure is the advantage that makes full use of the single-chip microcomputer micro computer, utilization digital filtering technique and automatic zero set (AZS) technology, and automatic error compensation or correction technique.

Claims (10)

1, a kind of centralized electronic electric meter comprises and assembles the shell of taking circuit board in that power supply is characterized in that being equipped with in the shell a plurality of submeters and a master meter;

Submeter wherein comprises the interface of overcurrent; The current transformation part is used to the electric current corresponding voltage signal of sending and importing; Display device;

Master meter wherein is by forming with the lower part:

The voltage transformation part is used to send and the corresponding low-voltage signal of added high voltage;

Analog switch is used for the current transformation of a plurality of submeters is partly transmitted the voltage signal conducting electedly of the reflection size of current of coming;

Analog to digital converter is used for above-mentioned voltage transformation part is become digital signal with the conversion of signals that current transformation is partly imported;

Processing and control element (PCE);

Storer comprises program storage, data-carrier store;

Input/output interface circuit comprises display driver circuit, transmission circuit, test port;

The electric current that each road submeter flows through is partly sent into analog switch in the master meter through current transformation, analog switch connection mode number converter, digital signal after conversion is sent into processing and control element (PCE), storer, input/output interface circuit are connected with processing and control element (PCE), calculating and the control display device that through input/output interface circuit be connected to submeter of the power information on each road by processing and control element (PCE).

2, centralized electronic electric meter according to claim 1 is characterized in that being connected to a sampling hold circuit before the above-mentioned analog to digital converter.

3, centralized electronic electric meter according to claim 1 is characterized in that above-mentioned current transformation part is made up of transformation resistance and amplifying circuit.

4, centralized electronic electric meter according to claim 1 is characterized in that above-mentioned processing and control element (PCE) is a microprocessor.

5, centralized electronic electric meter according to claim 1 is characterized in that above-mentioned analog to digital converter is integrated in the processing and control element (PCE).

6, centralized electronic electric meter according to claim 1 is characterized in that above-mentioned data-carrier store comprises static memory SRAM and long-term nonvolatile storage device EEPROM.

7, centralized electronic electric meter according to claim 1 is characterized in that in the master meter that the ground connection zero line of circuit in the circuit and submeter is all the zero line in the electric system.

8, centralized electronic electric meter according to claim 1 is characterized in that the display device of submeter comprises trigger circuit, stepper motor and the character wheel that links to each other with stepper motor.

9, centralized electronic electric meter according to claim 1 is characterized in that also including the period is provided with toggle switch.

10, centralized electronic electric meter according to claim 1 is characterized in that being connected to a signal pre-processing circuit before the above-mentioned analog to digital converter.

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