CN201181316Y - Ultra-low power consumption full-decompression measuring apparatus - Google Patents

Abstract

The utility model relates to an ultra-low power full-pressure-loss measuring device which is mainly used for measuring the power consumption of an electronic watt-hour meter, particularly the power consumption of a three-phase watt-hour meter. An analog-to-digital converter inside an MCU is adopted to perform the power metering. When batteries are adopted to power, the current and voltage passages are sampled under the condition of full-pressure-loss, and through two circuits with different magnification factors the current signal of each phase is input to the ADC input port of a microcontroller, and the current is divided into two different range sections. When the current in the different sections, the software installed in the microcontroller determines which relevant passage of current sample data is adopted to perform the metering. The ultra-low power full-pressure-loss measuring device has the advantages of simple, stable and reliable circuit structure, ultra-low energy consumption, full pressure loss measurement realization, low fabrication cost and easy promotion and application.

Description

Ultra low power consumption full-decompression measuring set

Technical field

The utility model relates to a kind of ultra low power consumption full-decompression measuring set, is mainly used in the measurement of electronic electric energy meter power consumption, and the particularly measurement of three-phase electric energy meter power consumption belongs to electric energy meter electronics measurement mechanism and makes the field.

Background technology

CN2578837Y, title " three-phase electric energy meter ", 1, a kind of three-phase electric energy meter, it is characterized in that: by three shunts respectively as three single-phase current sampled parts, also comprise three single-phase voltage sampled parts simultaneously, three single-phase electric energy computation chips, six smooth roll couplings, gather the resitstance voltage divider of each phase voltage phase place and amplitude and put woodenware, and EPLD, CPU, storer, display, communication interface, button is formed, the current phase signal output interface of the shunt of each phase links to each other with CPU by the photoelectricity isolated part, the voltage signal output interface of the current signal output interface of the shunt of each phase and the voltage sampling parts of each phase links to each other with electric energy computation chip, the electric power signal output interface of electric energy computation chip links to each other with CPU by photoelectricity isolated part (light lotus root), the voltage phase signal of resitstance voltage divider and amplifier, the output interface of amplitude signal and EPLD, CPU is attached to link to each other the CPU connected storage, display, communication interface, button.Its weak point: the one, circuit structure complexity, cost of manufacture height, poor reliability; The 2nd, measuring accuracy is low, the energy consumption height.

Summary of the invention

Purpose of design: avoid the weak point in the background technology, design that a kind of circuit structure is simple, cost of manufacture is low, stable and reliable for performance, measuring accuracy is high and energy consumption is ultralow ultra low power consumption full-decompression measuring set.

Design proposal: in order to realize above-mentioned purpose of design.1, the utility model adopts the MSP430 series monolithic, is one of feature of the present utility model.The MSP430 series monolithic is a super low-power consumption, the single-chip microcomputer of 16 RISC frameworks, MSP430F1xxx is arranged at present, subfamily such as MSP430F2xxx and MSP430F4xxx, MSP430F13x is wherein arranged, MSP430F14x, MSP430F15x, MSP430F16x, MSP430F43x, series such as MSP430F44x and MSP430FG461x all has the ADC12 module, use it in the measurement mechanism of three-phase electric energy meter, every phase current signal is by the circuit of two-way different amplification, import the ADC input port of microcontroller simultaneously, like this electric current is divided into two different range sections.When electric current is in different sections, judge by the software of microcontroller inside, adopt the current sampling data on corresponding that road to measure.Use this metered scheme, the ADC of employing 12bit can realize the three-phase electric energy metering of 0.5 class precision.Because this scheme is to adopt the analog to digital converter of MCU inside, rather than adopt the scheme of MCU+ electric energy computation chip to carry out electric energy metrical, therefore, uses very flexibly, can under full decompression state, during the employing powered battery, electric current and voltage channel be sampled.

Technical scheme: ultra low power consumption full-decompression measuring set, the output termination MSP430 microcontroller power supply end of battery, electric current and voltage channel current signal output end be the input end of connecting resistance dividing potential drop summation current transformer respectively, the output termination MSP430 single-chip microcomputer signal end of electric resistance partial pressure, the input end of the output termination size amplifying circuit of current transformer, the signal end of the output termination MSP430 single-chip microcomputer of big or small amplifying circuit.

The utility model is compared with background technology, and the one, circuit structure is simple, stable, reliable; The 2nd, super low energy consumption can be realized full decompression measurement; The 3rd, low cost of manufacture, easy to utilize.

Description of drawings

Fig. 1 is the three-phase electric energy meter block diagram that adopts the single-chip of MSP430.

Fig. 2 is in the three-phase multifunctional electrical energy meter current channel, wherein the circuit diagram synoptic diagram of the current channel of a phase.

Fig. 3 is in the three-phase multifunctional electrical energy meter current channel, wherein the circuit diagram synoptic diagram of the voltage channel of a phase.

Fig. 4 is the external voltage detection circuit diagram of three-phase multifunctional electrical energy meter.

Fig. 5 is three-phase multifunctional electrical energy meter master routine and interrupt routine process flow diagram.

Fig. 6 is a power consumption synoptic diagram under the full decompression state of three-phase multifunctional electrical energy meter.

Embodiment

Embodiment 1: with reference to accompanying drawing 1～6.Ultra low power consumption full-decompression measuring set, adopt the analog to digital converter of MCU inside to carry out electric energy metrical, under full decompression state, when adopting powered battery, electric current and voltage channel are sampled, every phase current signal is by the circuit of two-way different amplification, input to the ADC input port of microcontroller simultaneously and electric current is divided into two different range sections, when electric current is in different sections, software by microcontroller inside is judged, adopts the current sampling data on corresponding that road to measure.

Current channel is by PHASE, resistance R _1～7, capacitor C ₁, diode D _1～2, operational amplifier IC1A～IC2A constitutes, 1 pin and 2 pin of PHASE meet R respectively ₁And C ₁Two ends, D ₁Negative pole, D ₂Positive pole and R ₂, R ₃, R ₆An end to VREF/2, D ₂Negative pole meets VDD, D ₁Plus earth, R ₂The in-phase input end (the 3rd pin) of another termination IC1A, R ₃Inverting input (the 2nd pin and the R of another termination IC1A ₄An end, R ₄Output (the 1st pin), the R of another termination IC1A ₅An end to 1A-HIGH, R ₆The in-phase input end (the 3rd pin) of another termination IC2A, R ₅Inverting input (the 2nd pin) and the R of another termination IC2A ₇An end, R ₇The output (the 1st pin) of another termination IC2A to 1A-LOW.Current channel is input to the ADC12 analog port simultaneously by two stage amplifer, and VREF/2 is the booster tension of current channel, is provided by the reference voltage source of ADC12, and VDD is a controllable electric power, by its break-make of MCU control.

Voltage channel is by resistance R ₂₂～ ₂₈, capacitor C ₅～C ₄, diode D ₄～D ₅Constitute R ₂₂A termination R ₂₃An end, R ₂₃Another termination R ₂₄An end, R ₂₄Another termination R ₂₅, R ₂₆, R ₂₈An end and D ₄Negative pole and D ₅Positive pole, R ₂₅Another termination C ₅And C ₄One end, D ₄Anodal and ground, C ₅And C ₄Another termination R ₂₆The other end and R ₂₇An end, R ₂₇Another termination D ₅Negative pole and VDD, R ₂₈Another termination VA. voltage channel by the resistor network dividing potential drop, receive the analog input port of ADC12 then by resistance, VDD is a controllable electric power.

The measuring method of ultra low power consumption full-decompression measuring set, (1) in normal operation, MCU is in active state, each module such as ADC12 all is in open mode, the mode of operation of ADC12 is a sequence of channels unitary sampling pattern, and by the OUT1 triggering of Timer-A, the triggering frequency is 3276.8Hz, after sampling number reaches, just can calculate meritorious, idle, voltage, electric current, parameters such as power factor and frequency; (2) under full decompression state, the MCU overwhelming majority time is in low-power consumption mode, has only clock, when ADC12 measuring voltage and electric current were opened in renewal that LCD shows and timing, MCU started, simultaneously, ADC12, module such as timer and controllable electric power VDD are in closed condition; (3) timing measuring voltage, survey once general 60 seconds in the time interval of electric current, and the sample frequency of ADC12 is 3276.8Hz, and sampling number is the number of times of 1～2 cycle; After the sampling number of ADC12 has arrived, can close the VDD power supply, MCU enters active state simultaneously, and the beginning calculating parameter enters into low-power consumption mode again after calculating is finished.The master routine of ultra low power consumption full-decompression measuring set and interrupt routine are seen accompanying drawing 7.

One, the super low-power consumption characteristic of MSP430:

Realize full decompression measurement, require the low in energy consumption of MCU, powerful.The MSP430 series monolithic is a super low power consuming single chip processor, has following characteristics:

1, operating voltage: 1.8V-3.6V

2, super low-power consumption: activity pattern: 200 μ A (2.2V, 1MHz)

Standby mode: 1.1 μ A

" shut " mode" (RAM maintenance): 0.1 μ A

3,5 kinds of battery saving modes: wake up from standby mode and to be less than 6 microseconds, MSP430F2xxx series is waken up from standby mode and is less than 1 microsecond; 16 risc architectures, 125 instruction cycles nanosecond; The MSP430F2xxx series of instructions cycle was 62.5 nanoseconds;

4, have abundant peripheral module: ADC12,

16 bit timing device Timer_B (catching/comparand register for 7)

16 bit timing device Timer_A (catching/comparand register for 3)

Two-way serial communication interface: USART0, USART1

Hardware multiplier

Integrated 160 sections LCD drive

Built-in analog comparator Comparator_A

5, electrify restoration circuit, supply voltage management monitor module.

Two, three-phase multifunctional ammeter current channel, voltage channel and system voltage monitoring:

1, Fig. 2 is the circuit diagram of the current channel of a phase wherein: electric current is input to the ADC12 analog port simultaneously by two stage amplifer, VDD is a controllable electric power, under full decompression state, can be controlled its break-make by MCU, VREF/2 is the booster tension of current channel, and it is provided by the reference voltage source of ADC12.

2, Fig. 3 is the circuit diagram of the voltage channel of a phase wherein: three-phase voltage is received the analog input port of ADC12 then by the resistor network dividing potential drop by resistance, VDD is a controllable electric power.

3, Fig. 4 is the external voltage detection circuit: system voltage Vsupply is by behind the electric resistance partial pressure, is connected to two the input pin CA0 and the CA1 of comparer.When the outside cut off the power supply, Vsupply began to descend, but comparer prior notice system enters into the real-time clock state of super low-power consumption like this.

Three, three-phase multifunctional electrical energy meter principle of work:

In normal operation, MCU is in active state, and each module such as ADC12 all is in open mode.

The mode of operation of ADC12 is a sequence of channels unitary sampling pattern, and by the OUT1 triggering of Timer-A, the triggering frequency is 3276.8Hz.After sampling number reaches, just can calculate meritorious, idle, voltage, electric current, parameters such as power factor and frequency, its computing formula:

$E_{\mathrm{act}}=\underset{k=0}{\overset{N}{\mathrm{\Σ}}}{u}_k{i}_k$

$U=\sqrt{\frac{1}{N}\underset{k=0}{\overset{N}{\mathrm{\&Sigma;}}}{u}_{\mathrm{<figure-callout\; id="2"\; label="k"\; filenames="Y20072011446300082.png"\; state="\{\{state\}\}">k</figure-callout>}}^2}$

$I=\sqrt{\frac{1}{N}\underset{k=0}{\overset{N}{\mathrm{\&Sigma;}}}{i}_{\mathrm{<figure-callout\; id="2"\; label="k"\; filenames="Y20072011446300082.png"\; state="\{\{state\}\}">k</figure-callout>}}^2}$

$E_{\mathrm{react}}=\underset{k=0}{\overset{N}{\mathrm{\&Sigma;}}}{u}_{90}{}_{k}i_k$

$E_{\mathrm{apparent}}=\sqrt{{\mathrm{<figure-callout\; id="2"\; label="E\; act"\; filenames="Y20072011446300082.png"\; state="\{\{state\}\}">E</figure-callout>}}_{\mathrm{act}}^{}+E_{\mathrm{react}}^2}$

Under full decompression state, the MCU overwhelming majority time is in low-power consumption mode 3, has only clock, when ADC12 measuring voltage and electric current were opened in renewal that LCD shows and timing, MCU was only movable, simultaneously, ADC12, module such as timer and controllable electric power VDD also the overwhelming majority times be in closed condition, only when measuring voltage and electric current, just open, can save power consumption greatly like this.

Regularly measuring voltage in the time interval of electric current, can determine that survey general 60 seconds once is acceptable according to concrete demand.The sample frequency of ADC12 still can be 3276.8Hz, and sampling number can be the number of times of 1-2 cycle.

After the sampling number of ADC12 has arrived, just can close the VDD power supply, MCU enters active state simultaneously, and the beginning calculating parameter enters into low-power consumption mode 3 again after calculating is finished.

Above-mentioned computing formula is a prior art, is not described herein at this.

Four, the power consumption analysis under the full decompression state:

Fig. 7 is a power consumption synoptic diagram under the full decompression state.

In the LPM3 pattern, under the 3.3V, the electric current representative value is: 1.6uA, maximal value is: 1.9uA

LCD drives: 0.8uA

RTC function: 0.03uA

LCD: 3.5uA

Realize that so the needed average power consumption of real-time clock function is: 1.6uA+0.8uA+0.03uA+3.5uA=5.93uA

During measuring, the device and the module of institute's power consumption have:

The needed electric current of voltage channel is: 3 * 3.3V/ (10K+15K+0.01K)=396uA

The required electric current of the amplifier of current channel is: 2 * 410uA=820uA

The required electric current of ADC12 module is: 800uA

The required electric current of reference voltage REF of ADC12 is: 500uA

CPU is operated in the required electric current of 3.3V/8MHz: (420+175uA/V * (3.3V-3V)) * 8=3780uA

When measuring, at first need power vd D is opened, the reference voltage VREF with ADC12 opens simultaneously, and the stable of reference voltage and VDD calculates by the longest 17ms, and at voltage between stationary phase, CPU can be in the LPM3 state.The sampling number of ADC12 is 2 cycles 131 times, and the time is 40ms, and in ADC12 sampling and transition period, CPU can be in the LPM0 pattern, still is in activity pattern by CPU here and considers.

After sampling was finished, CPU calculated required time: 8298/8388608=990us

Like this, measured by per 60 seconds and once to calculate, measure required average power consumption and be:

[(396uA+820uA+500uA)×(17+40)+3780uA×(40+0.99)]/1000/60＝4.22uA

Total average power consumption is: 5.93uA+4.22uA=10.15uA

The battery of a 1.2Ah is not considered factors such as self discharge, is limited in spendable year: 1.2 * 1000000uAh/10.15uA/24h/365d=13.5.

What need understand is: though the foregoing description is to the utility model detailed explanation of contrasting; but these explanations; just to simple declaration of the present utility model; rather than to restriction of the present utility model; any innovation and creation that do not exceed in the utility model connotation all fall in the protection domain of the present utility model.

Claims (5)

1, a kind of ultra low power consumption full-decompression measuring set, it is characterized in that: the output termination MSP430 microcontroller power supply end of battery, electric current and voltage channel current signal output end be the input end of connecting resistance dividing potential drop summation current transformer respectively, the output termination MSP430 single-chip microcomputer signal end of electric resistance partial pressure, the input end of the output termination size amplifying circuit of current transformer, the signal end of the output termination MSP430 single-chip microcomputer of big or small amplifying circuit.

2, ultra low power consumption full-decompression measuring set according to claim 1 is characterized in that: current channel is by PHASE, resistance R _1～7, capacitor C ₁, diode D _1～2, operational amplifier IC1A～IC2A constitutes, 1 pin and 2 pin of PHASE meet R respectively ₁And C ₁Two ends, D ₁Negative pole, D ₂Positive pole and R ₂, R ₃, R ₆An end to VREF/2, D ₂Negative pole meets VDD, D ₁Plus earth, R ₂The in-phase input end of another termination IC1A, R ₃Inverting input and the R of another termination IC1A ₄An end, R ₄Output terminal, the R of another termination IC1A ₅An end to 1A-HIGH, R ₆The in-phase input end of another termination IC2A, R ₅Inverting input and the R of another termination IC2A ₇An end, R ₇Another termination IC2A export 1A-LOW to.

3, ultra low power consumption full-decompression measuring set according to claim 1 and 2, it is characterized in that: current channel is input to the ADC12 analog port simultaneously by two stage amplifer, VREF/2 is the booster tension of current channel, reference voltage source by ADC12 provides, VDD is a controllable electric power, by its break-make of MCU control.

4, ultra low power consumption full-decompression measuring set according to claim 1, it is characterized in that: voltage channel is by resistance R _22～28, capacitor C ₅～C ₄, diode D ₄～D ₅Constitute R ₂₂A termination R ₂₃An end, R ₂₃Another termination R ₂₄An end, R ₂₄Another termination R ₂₅, R ₂₆, R ₂₈An end and D ₄Negative pole and D ₅Positive pole, R ₂₅Another termination C ₅And C ₄One end, D ₄Anodal and ground, C ₅And C ₄Another termination R ₂₆The other end and R ₂₇An end, R ₂₇Another termination D5 negative pole and VDD, R ₂₈Another termination VA.

5, according to claim 1 or 4 described ultra low power consumption full-decompression measuring sets, it is characterized in that: voltage channel is received the analog input port of ADC12 then by the resistor network dividing potential drop by resistance, VDD is a controllable electric power.

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