CN1292259C - Electronic watthour meter and power-associated quantity calculation circuit - Google Patents

Abstract

The present invention relates to an L-multiple sampling frequency compensation device used for tracing the sampling frequency of AD conversion to the power supply frequency and a voltage controlling oscillator (VCO). The present invention controls the sampling frequency of an AD converter with high precision and obtains a power correlation quantum with high precision as a result. The needed reactive power by the power supply efficiency can be measured and mastered with high precision especially in the mode containing higher-order harmonics, and a power factor of an index for effective utilization of the power can be obtained with high precision.

Description

Electronic watt-hour meter and power associated volume computing circuit

Technical field

The present invention relates to measure the related computing circuit of electronic watt-hour meter of electric energy with power, relate in particular to can computing the phase differential, the electronic watt-hour meter and the power associated volume computing circuit of above all each higher hamonic wave value constant power associated volume of active power, active energy, reactive power, reactive energy, applied power, distortion power, current effective value, voltage effective value, electric current and voltage.

Background technology

Existing example 1

Existing electronic watt-hour meter, for example with reference to No. 3080207, Japan's patent, make the device that wherein conduct is transformed into the analog quantity of the voltage and current of voltage sensor (PT) and current sensor (CT) measurement digital value, has the 1st and the 2nd comparison A/D transducer one by one, and after by multiplier computing being carried out in these numeral outputs (voltage and current), obtain power W.

1st, the 2nd one by one the comparison A/D transducer usually analog input signal is changed into output quantity to equate

The discrete digital value that increases of resolution, thereby, need the high-resolution transducer of comparison A/D one by one for low imput being obtained absolute number conversion precision.

On the other hand, as the method that improves the digital conversion precision, known method is raising the 1st, the 2nd sample frequency of comparison A/D transducer (" raising frequency sampling ") one by one.For example, when bringing up to sample frequency according to 128 times of the frequency of Nyquist's theorem decision frequency, quantizing noise is diffused into roomy frequency band, thereby the vector level of each frequency component reduces, and improves the noise level of signal frequency component.This situation be equivalent to make the 1st and the 2nd one by one the resolution of comparison A/D transducer improve several.

Yet in order to obtain high-precision electronic formula galvanometer with above-mentioned existing example 1, needs the high-resolution the 1st and the 2nd are comparison A/D transducer and the multiplier of importing multidigit one by one, thereby the circuit structure complexity, causes cost to improve.Especially wishing monolithic ICization, when producing in batches, becoming very disadvantageous condition with realization.

Existing example 2

In No. 3080207, the above-mentioned Japan patent, as 1 example that addresses the above problem usefulness, the method that discloses is: after respectively electric current and voltage being carried out integration with integrator, by comparer output digital value, should numeral output be postponed simultaneously, and the value of D/A conversion gained is fed back to the input end of above-mentioned integrator.

This situation have utilize the raising frequency sample frequency quantize respectively described electric current and voltage the 1st and the 2nd delta sigma AD modulator, utilize digital filter respectively to quantize the 1st and the 2nd moving average treating apparatus that electric current and voltage carries out moving average, electric current after moving average is handled and voltage multiplies each other and obtains the integrating device that the multiplier of performance number and accumulative total are utilized the performance number that multiplication tries to achieve.

Like this, according to existing example 2, can reduce the low-frequency range noise significantly.That is, compare during with type AD transducer one by one, effective carry-out bit of AD transducer increases in fact, thereby can obtain high-precision electronic formula electric energy meter with simple circuit configuration, especially when monolithic ICization, can make the circuit summary.

Yet, as indicated above, existing electronic watt-hour meter, owing to require to measure in real time (or demonstration) electric energy, each sampling timing (AD converter sample fixed-frequency) directly multiplies each other electric current and voltage, with the computing electric energy.Obtain high fdrequency component input signal (electric current and voltage) more than the nyquist frequency by low-pass filter again, with the computing electric energy.The electric energy of calculating like this is first-harmonic and the synthetic electric energy of higher hamonic wave, can not only measure first-harmonic or only measure higher hamonic wave.Can not measure reactive power and higher hamonic wave reactive power.

In addition, in the power apparatus in recent years, much use controllable silicon and inverter, often comprise higher hamonic wave in the electric current, thereby require the various measurements that contain the power associated volume of higher hamonic wave.

Here, carry out computing if applying detection goes out the well known Fourier transform of higher harmonic components, then existing electric energy meter also can be thought the energy measurement higher harmonic components in logic.Yet the sample frequency of AD transducer is not the natural several times of supply frequency, thereby adjacent number of times (Fourier transform result, the K order harmonic components becomes the K+1 order harmonic components) also comprises the Fourier transform value of electric current and voltage.

Therefore,, make AD converter sample fixed-frequency, need to adopt the higher hamonic wave correction computing of supply frequency in order to obtain higher harmonic components.Revise computing for this, not only need to detect supply frequency, and computing itself is also had requirement, thereby, need the processor (CPU) of high price especially as the electronic watt-hour meter that requires real-time.

At this moment, as the ingredient different with the electronic watt-hour meter purposes, need with the identical ingredient of measuring equipment of the high precision of AD transducer that the high-speed sampling frequency is housed and high arithmetic speed processor and high price, thereby as not adopting in the general electronic watt-hour meter of civil goods.

On the other hand, when adopting the delta sigma AD transducer that has example 2 (or) is example when lift utilizing the transducer of the AD one by one raising frequency sampling of using existing example 1 to measure, then the raising frequency sample frequency is hundreds of kHz～tens MHz (＞＞several kHz), and the output clock resolution of CPU is several MHz～tens MHz, thereby can not be from COU High Accuracy Control sample frequency.

In addition,, utilize Hilbert transform that electric current is rotated, active power that then can the computing first-harmonic and reactive power etc. as previous patented claim (PCT2002JP00045: unexposed) the institute record that proposes such as inventor.Yet, can revolve the frequency range that turn 90 degrees narrow (first-harmonic can revolve the angle that the Hilbert transform device higher hamonic wave rotation that turn 90 degrees departs from 90 degree down) with same Hilbert transform device, thereby be difficult to obtain first-harmonic reactive power in addition with 1 Hilbert transform device.

Existing electronic watt-hour meter and power associated volume computing circuit are formed as described above, in order to obtain high precision with the electronic current meter of existing example 1, needs the high-resolution the 1st and the 2nd are comparison A/D transducer and the multiplier of importing multidigit one by one, thereby there is the circuit structure complexity, the problem that causes cost to improve.

Each sampling of existing electronic watt-hour meter is regularly directly multiplied each other electric current and voltage, with the computing electric energy, calculate the synthetic electric energy of first-harmonic and higher hamonic wave, thereby can not only measure first-harmonic or higher hamonic wave, nor energy measurement reactive power and higher hamonic wave reactive power.Existing problems.

In the time of will measuring radio-frequency component with known Fourier transform, the sample frequency of AD transducer is not the natural several times of supply frequency, adjacent order also comprises the Fourier transform value, need to adopt the higher hamonic wave correction computing of supply frequency, thereby processor at high price will be arranged, there is the problem that can not adopt in the universal electronic type electric energy meter.

When utilization makes one by one AD transducer raising frequency sampling measure or when adopting delta sigma AD transducer, because raising frequency sample frequency very high (hundreds of kHz～several MHz), can not the High Accuracy Control sample frequency with the resolution (several MHz～tens MHz) of CPU output clock, must need to follow the tracks of the sample frequency of AD transducer, and revise computing by the natural several times of supply frequency.Existing problems.

Utilize Hilbert transform to make the electric current rotation, during with the active power of computing first-harmonic and reactive power, the frequency range that turn 90 degrees is narrow owing to revolving with same Hilbert transform device, and existence can not be asked the problem of first-harmonic reactive power in addition with 1 Hilbert transform device.

The present invention finishes for addressing the above problem, and its purpose is to provide the sample frequency control accuracy to improve and can obtain accurately the electronic watt-hour meter and the power associated volume computing circuit of electric energy.

Electronic watt-hour meter and power associated volume computing circuit that another object of the present invention provides is simple in structure, can not only measure fundamental energy and energy measurement higher hamonic wave electric energy.

Purpose of the present invention especially provides can high precision and contain higher hamonic wave ground and measure and check that reactive power that power-efficient is required and high precision obtain the electronic watt-hour meter and the power associated volume computing circuit of the power factor that becomes the index that power effectively utilizes.

Summary of the invention

A kind of electronic watt-hour meter of the present invention, comprise: the measuring-signal that will represent the electric current of power circuit and voltage is transformed into digital value and is taken into the AD transducer of usefulness, and the microprocessor that comprises the electric energy arithmetic unit of using according to the electric energy of the described power circuit of described digital value computing; This electronic watt-hour meter also possesses: the supply frequency pick-up unit that detects the supply frequency of described power circuit, be arranged with the clock circuit branch of described microprocessor and control the sample frequency control device of the sample frequency of described AD transducer according to described supply frequency, the voltage controlled oscillator that the sample frequency of described AD transducer is changed corresponding to control voltage from described sample frequency control device; Described sample frequency control device is controlled described sample frequency, and making described sample frequency is the natural several times of described supply frequency, and described electric energy arithmetic unit comprises the higher hamonic wave operational part that computing higher hamonic wave electric energy is used.Therefore, can improve the sample frequency control accuracy, obtain electric energy accurately.

Make the control sample frequency on the sample frequency control device structure, making sample frequency is the natural several times of supply frequency, and the electric energy arithmetic unit comprises the higher hamonic wave operational part that computing higher hamonic wave electric energy is used.Therefore, can be with the electric energy of simple structure measurement first-harmonic and higher hamonic wave.

Make the control sample frequency on the sample frequency control device structure, making sample frequency is that 2 n power, n of supply frequency is natural number, and the electric energy arithmetic unit comprises the fast Fourier transform device, utilizes fast Fourier transform (FFT) computing higher hamonic wave electric energy.Therefore, can make the computing high speed, real-time is good.

The AD transducer is made up of the delta sigma type AD transducer that needs raising frequency sampling, thereby precision height and be suitable for monolithic ICization.

The sample frequency control device, the zero cross point pick-up unit that comprises the zero cross point that detects the supply frequency rising or descend, and power phase device for detecting difference, this pick-up unit behind the rising of supply frequency last time (last 1) or decline zero cross point through moment in 1 cycle, detect that supply frequency lags or in advance from the AD transformed value of supply frequency, poor as power phase, also have device according to the sample frequency of power phase difference control AD transducer.Therefore, can make cpu load little, and simple in structure.

The sample frequency control device, the absolute phase pick-up unit that comprises the voltage absolute phase that detects power circuit, after the last time of voltage absolute phase, detect through the moment in 1 cycle that absolute phase lags or in advance as the voltage-phase device for detecting difference of voltage phase difference, and according to the device of the sample frequency of voltage phase difference control AD transducer.Therefore, can suppress the influence of white noise.

The voltage-phase device for detecting difference as benchmark, thereby can be widened setting range with the absolute phases of 0 degree, 90 degree, 180 degree or 270 degree.

Make the sample frequency control device on the structure, sample frequency compensation system with sample frequency of compensation AD transducer, the sample frequency compensation system comprises the controlled quentity controlled variable arithmetic unit of the controlled quentity controlled variable of asking the up-sampling frequency, the D/A converting means that the controlled quentity controlled variable of sample frequency is exported after the D/A conversion in addition, and the bias unit that makes the output voltage biasing of D/A converting means, bias unit makes the assigned frequency lateral deviation of power circuit put assigned voltage.Therefore, can use simple and the few D/A converting means of figure place.

The bias voltage adjusting gear that described assigned voltage is used is adjusted in setting from the outside, thereby can be used for various circuit, and can use simple and the few D/A transducer of figure place.

The electric energy arithmetic unit, the AD transform data packaging system of voltage and current measuring-signal that comprises 1 cycle share of packaging power frequency, the data of AD transform data packaging system encapsulation are carried out the Power arithmetic device of Fourier transform and computing the 1st performance number, detect the encapsulation time detection device of 1 required encapsulation time of share voltage and current in cycle of encapsulation, the sampling of every generation regulation execution cycle instruction output the 1st performance number is as the power output device of the 2nd performance number when each encapsulation time keeps the 1st performance number, and the electrical energy pulse output unit of the aggregate-value of accumulative total the 2nd performance number and described the 2nd performance number output electrical energy pulse when at every turn reaching setting.Therefore, can satisfy real-time.

The electric energy arithmetic unit, the AD transform data packaging system of voltage and current measuring-signal that comprises 1 cycle share of packaging power frequency, the data of AD transform data packaging system encapsulation are carried out the power relating value (electric current of Fourier transform and each higher hamonic wave of computing, voltage, active power, reactive power) and the Power arithmetic portion of the phase differential of power relating value, and phase compensation device, this compensation system passes through twiddle operation, make the phase differential of power relating value become measured side's real power relating value phase differential, the curtage of 1 cycle share is compensated.Therefore, can improve measuring accuracy.

Power associated volume computing circuit of the present invention, comprise that measuring-signal with expression electric current of power circuit and voltage is transformed into digital value and takes in the AD transducer of usefulness, AD transform data packaging system by 1 cycle share encapsulation digital value, the data of AD transform data packaging system encapsulation are carried out the Fourier transform device of Fourier transform, power associated volume arithmetic unit according to the transformation results computational calculation power associated volume of Fourier transform device, according to the sample frequency compensation system of the sample frequency compensation rate of the frequency calculation AD transducer of curtage, and will output to the voltage controlled oscillator of AD transducer with the sample frequency that compensation rate changes.Therefore, can improve the sample frequency control accuracy, obtain electric energy accurately.

As above-mentioned circuit structure, the present invention use L that the sample frequency with the AD conversion traces into supply frequency doubly the sample frequency compensation system and the voltage controlled oscillator (VCO) of (L is a natural number) control the sample frequency of AD transducer accurately, thereby obtain the power associated volume accurately.Especially can measure accurately in the mode that comprises higher hamonic wave and grasp the required reactive power of power-efficient, and can obtain the power factor that becomes the effective index of utilizing of power accurately.

Description of drawings

Fig. 1 represents the key diagram of the power associated volume arithmetic logic of the invention process form 1, and wherein the polar plot with voltage and current illustrates as an example.

Fig. 2 represents the block diagram that the electronic watt-hour meter key component circuit of the invention process form 1 is formed.

The key diagram that moves about of fundamental voltage when Fig. 3 represents that the supply frequency of the electronic watt-hour meter of the invention process form 1 changes.

Fig. 4 represents the key diagram of supply voltage zero cross point and sampling starting point in the electronic watt-hour meter of the invention process form 1.

Fig. 5 represents the block diagram that the electronic watt-hour meter key component circuit of the invention process form 2 is formed.

Fig. 6 represents in the invention process form 2 that the sample frequency with the AD transducer traces into the key diagram of the compensation deals that the natural several times of supply frequency use.

Fig. 7 represents the key diagram of sampling starting point of the electronic watt-hour meter of the invention process form 3.

Fig. 8 represents the block diagram that the electronic watt-hour meter key component circuit of the invention process form 4 is formed.

Fig. 9 represents to utilize the electronic watt-hour meter of the invention process form 4 to make VCO control the key diagram of the running example of voltage bias.

Figure 10 represents to utilize the electronic watt-hour meter of the invention process form 4 further to adjust the composition frame chart that VCO controls the voltage adder circuit of voltage.

Figure 11 represents the block diagram that the electronic watt-hour meter key component circuit of the invention process form 5 is formed.

Figure 12 represents the sequential chart that the electrical energy pulse of the electronic watt-hour meter of the invention process form 5 is exported.

Figure 13 represents the block diagram that the electronic watt-hour meter key component circuit of the invention process form 6 is formed.

The optimal morphology that carries out an invention

Example 1

The following describes example 1 of the present invention.

The present invention is different with the computing of existing electronic watt-hour meter, utilizes the data of 1 cycle share are carried out Fourier transform (FFT is good), computing electric energy etc.

The arithmetic logic of at first, simple declaration the invention process form 1 usefulness.

When the sample frequency of AD transducer is the natural several times of supply frequency, can utilize Fourier transform to measure following power associated volume.

The sample frequency that makes the AD transducer is L times (L is a natural number) of supply frequency, and higher hamonic wave is n time.During n=0, be direct current (DC) component; During n=1, be first-harmonic (1 subharmonic).At this moment, utilize the getable maximum higher hamonic wave H of Fourier transform with following formula (1) expression.

H=floor (L/2) (1) wherein, in the formula (1), floor () is the function that radix point Yi Xia Hall is gone, thereby H is a natural number.

The data that the L that conversion obtains to AD is ordered are carried out Fourier transform, the complex values that has amplitude and phase information that then can be from DC component to the H order harmonic components.Make AD transform data L point to voltage and current carry out the resulting nth harmonic complex values of Fourier transform and be respectively Vn_cmp, In_cmp, then can be with it with following formula (2), formula (3) expression.

Vn_cmp＝Vn_re+j·Vn_im (2)

In_cmp＝In_re+j·In_im (3)

Wherein, in formula (2), the formula (3), j is the imaginary number unit, and " " is multiplication symbol.Vn_re, Vn_im, In_re, In_im are real number.Below, the value after the Fourier transform is with the normalized value of effective value.

Here, ask the active power Wn of nth harmonic with following formula (4).

Wn＝Vn_re·In_re+Vn_im·In_im (4)

Ask the power W that comprises whole higher hamonic waves with following formula (5).

$W=\underset{n=0}{\overset{H}{\mathrm{\Σ}}}\mathrm{Wn}---\left(5\right)$

Here, ask the reactive power varn of nth harmonic with following formula (6).

Varn＝Vn_im·In_re-Vn_re·In_im (6)

At this moment, reactive power is for just, and then electric current lags to voltage; Reactive power is for negative, and then electric current is leading to voltage.In addition, ask the reactive power that comprises whole higher hamonic waves with following formula (7).

$\mathrm{Var}=\underset{n=0}{\overset{H}{\mathrm{\Σ}}}\mathrm{Varn}---\left(7\right)$

Ask the voltage effective value Vrmsn of nth harmonic with following formula (8).

$\mathrm{Vrmsn}=\sqrt{\mathrm{Vn}\_\mathrm{re}\·\mathrm{Vn}\_\mathrm{re}+\mathrm{Vn}\_\mathrm{im}\·\mathrm{Vn}\_\mathrm{im}}---\left(8\right)$

Ask the voltage effective value Vrms that comprises whole higher hamonic waves with following formula (9).

$\mathrm{Vrms}=\underset{n=0}{\overset{H}{\mathrm{\Σ}}}\mathrm{Vrmsn}---\left(9\right)$

Ask the current effective value Irmsn of nth harmonic with following formula (10).

$\mathrm{Irmsn}=\sqrt{\mathrm{In}\_\mathrm{re}\·\mathrm{In}\_\mathrm{re}+\mathrm{In}\_\mathrm{im}\·\mathrm{In}\_\mathrm{im}}---\left(10\right)$

Ask the current effective value Irms that comprises whole higher hamonic waves with following formula (11).

$\mathrm{Irms}=\underset{n=0}{\overset{H}{\mathrm{\Σ}}}\mathrm{Irmsn}---\left(11\right)$

Ask the applied power VAn of nth harmonic with following formula (12).

VAn＝Vrmsn·Irmsn (12)

Ask the applied power VA that comprises whole higher hamonic waves with following formula (13).

VA＝Vrms·Irms (13)

If only there are first-harmonic in supply voltage and electric current, then the relation of active power W, reactive power and applied power VA satisfies following formula (14).

$\mathrm{VA}=\sqrt{W\·W+\mathrm{Var}\·\mathrm{Var}}---\left(14\right)$

Yet when having higher hamonic wave, above-mentioned formula (14) is false, and has distortion power.Ask distortion power D with following formula (15).

$D=\sqrt{\mathrm{VA}\·\mathrm{VA}-W\·W-\mathrm{Var}\·\mathrm{Var}}---\left(15\right)$

Distortion power D is an arithmetic number, is not negative value.

The resulting nth harmonic voltage and current of Fourier transform complex values Vn_cmp and In_cmp are as polar plot, as shown in Figure 1.Among Fig. 1, transverse axis is a real axis, and the longitudinal axis is the imaginary axis.

Among Fig. 1, θ is the absolute phase of complex values Vn_cmp, and φ is the absolute phase of complex values In_cmp.Here, the benchmark of absolute phase is the forward of transverse axis, and counter-clockwise direction is represented (just) in advance, clockwise direction represent to lag (bearing).

As benchmark, (φ-θ) is Phase_VnIn to the phase differential of Vn_cmp and In_cmp, then uses following formula (16) to ask phase differential Phase_VnIn with complex values Vn_cmp.

if?varn＞＝0

Phase_VnIn＝-arccos(Wn/VAn)

else (16)

Phase_VnIn＝arccos(Wn/VAn)

Phase differential Phase_VnIn is " just " when electric current is leading to voltage, then is when lagging " bearing ".The scope of phase differential Phase_VnIn is ± 180 degree.

Above, only set forth single-phase 2 line formulas, but can ask single-phase 3 line formulas, three-phase 3 line formulas, three-phase 4 line formulas equally.The value after each value addition of trying to achieve mutually and the power of addition gained utilize formula (16) can ask active power, reactive power and applied power and distortion power respectively.

Also can ask the phase place between the voltage of each phase again.That is, at first making the nth harmonic voltage Van_cmp of A phase is following formula (17).

Van_cmp＝Van_re+j·Van_im (17)

Making B phase nth harmonic voltage Vbn_cmp again is following formula (18).

Vbn_cmp＝Vbn_re+j·Vbn_im (18)

At this moment, asking with A with following formula (19) is the phase differential Phase_VanVbn of benchmark mutually.

Vabn＝Van_re·Vbn_re+Van_im·Vbn_im

Vabn′＝Van_im·Vbn_re-Van_re·Vbn_im

$\mathrm{Varmsn}=\sqrt{\mathrm{Van}\_\mathrm{re}\·\mathrm{Van}\_\mathrm{re}+\mathrm{Van}\_\mathrm{im}\·\mathrm{Van}\_\mathrm{im}}$

$\mathrm{Vbrmsn}=\sqrt{\mathrm{Vbn}\_\mathrm{re}\·\mathrm{Vbn}\_\mathrm{re}+\mathrm{Vbn}\_\mathrm{im}\·\mathrm{Vbn}\_\mathrm{im}}$

if?Vabn′＞＝0

$\mathrm{Phase}\_\mathrm{VanVbn}=-\arccos \left(\frac{\mathrm{Vabn}}{\mathrm{Varmsn}\·\mathrm{Vbrmsn}}\right)$

else

$\mathrm{Phase}\_\mathrm{VanVbn}=\arccos \left(\frac{\mathrm{Vabn}}{\mathrm{Varmsn}\·\mathrm{Vbrmsn}}\right)$

(19)

In the formula (19), Vabn represents the virtual active power that ab is alternate, the alternate virtual reactive power of Vabn ' expression ab.

Even the voltage and current that phase place is different also can be calculated phase differential with identical method.

Like this, the sample frequency that makes the AD transducer is the natural several times of supply frequency, then utilizes the computing structure of Fourier transform each higher hamonic wave to obtain whole power associated volumes that comprise higher hamonic wave or the power associated volume that comprises required higher hamonic wave.

Especially whole higher hamonic waves are obtained reactive power, this point should be write volumes about.In addition, the sample frequency that makes the AD transducer is 2 N the power doubly (N is a natural number) of supply frequency, and then the computing of Fourier transform can be used FFT.Therefore, the sample frequency that makes the AD conversion usually is the natural several times of supply frequency, and is that 2 N power is doubly preferable.

The following describes the concrete running of the electronic watt-hour meter of the invention process form 1.

Here, the method for utilizing the supply voltage zero cross point to lock as the VCO control method explanation of the invention process form 1.

Fig. 2 illustrates the block diagram that the physical circuit of the electronic watt-hour meter of the invention process form 1 is formed.

Among Fig. 2, AD transducer 1 is transformed into digital value with detected voltage V of sensor (not shown) and electric current I.The lead-out terminal of AD transducer 1 connects AD data encapsulation apparatus 2, Fourier transform device 3 and power associated volume arithmetic unit 4 successively.

The voltage and current measuring-signal of 1 cycle share of AD data encapsulation apparatus 2 packaging power frequencies.This device 2 has the function that detects the supply frequency on the power circuit and detects the device of the zero cross point of supply frequency rising or decline.

Fourier transform device 3 carries out Fourier transform.Power associated volume arithmetic unit 4 (electric energy arithmetic unit) contains the higher hamonic wave operational part that the power associated volume of higher hamonic wave uses as computing and works.

The data of AD transform data packaging system 2 encapsulation are input to the voltage controlled oscillator (hereinafter being designated as VCO) of control AD transducer 1 usefulness by sample frequency compensation system 5.

Being input to the voltage V of AD transducer 1 and the output that electric current I is sensor, is not the physics voltage and current itself on the power supply, is the value that cooperates 1 input of AD transducer.The (not shown)s such as operational amplifier that the input end of AD transducer 1 is provided with frequency overlapped-resistable filter sometimes and is used to amplify.

AD transform data packaging system 2 is at the AD transform data of 1 cycle share of each L point sink general supply.

Fourier transform device 3 each L point (each cycle) carry out Fourier transform to the AD transform data (L point) of 1 power cycle share of AD transform data packaging system 2 inputs.

The complex values computational calculation power associated volume of the voltage and current after power associated volume arithmetic unit 4 is handled from Fourier transformation operation.

Sample frequency compensation system 5 keys are from the data of AD transform data packaging system 2 inputs, and the voltage output of VCO6 is given in control, make AD transformed samples frequency lock natural number L times in supply frequency.

VCO6 becomes clock output with the voltage output transform of sample frequency compensation system.Clock output from VCO6 to AD transducer 1 equals sample frequency, and when delta sigma AD transducer, equals the raising frequency sample frequency when AD transducer 1 is one by one AD transducer 1.When but AD transducer 1 had the clock signal division function, VCO6 provided the output of the clock before the frequency division.

Below, with reference to the key diagram of Fig. 3 and Fig. 4, the running of the invention process form 1 shown in Figure 2 is described.

At first, according to Fig. 3 sample frequency compensation system 5 is described.Identical with Fig. 1, Fig. 3 illustrates the vector space of being made up of the real axis (transverse axis) and the imaginary axis (longitudinal axis).As shown in Figure 3, the phase place of first-harmonic lags when supply frequency lags, and leading when leading, so that the AD transformed samples frequency of example VCO6 is controlled so as to fundamental phase is leading when leading, and lags when lagging.The simplest method of carrying out this control is a FEEDBACK CONTROL.

Here, if feedback factor is ε, the VCO that carries out for the m time control voltage is Vcntrl_m, and the phase differential of the m time voltage fundamental and the m+1 time voltage fundamental is Ψ (leading for just), then uses following formula (20) to represent that the VCO that carries out for the m+1 time controls voltage Vcntrl_m+1.

Vcntrl _{_m+1}＝Vcntrl _{_m}+ε·Ψ (20)

Here, VCO control magnitude of voltage is big more, and clock frequency is high more.Feedback factor ε (ε＞0) is by decisions such as VCO6 that appropriate value is used to control and tracking velocities.

The margin of error as the feedback of carrying out above-mentioned formula (20), when former state is used phase differential, the trigonometric function operation that need ask phase place to use increases operand, thereby will have the amount of corresponding one by one and dull increase or the dull relation that reduces as the margin of error to phase difference.This margin of error of sampling Error, then available following formula (21) is represented above-mentioned formula (20).

Vcntrl _{_m+1}＝Vcntrl _{_m}-ε·Error (21)

Here, when margin of error Error lags (phase lag) in supply frequency on the occasion of, and be negative value during supply frequency leading (phase place is leading).Therefore, to the phase differential monotone increasing added-time, sign inversion, and the value that monotone decreasing after a little while can be original with it is as margin of error Error.

In order to reduce operand,, carry out the processing of following relevant frequency-tracking with the amount beyond the margin of error Error displacement phase place.

Usually utilize the D/A transducer to produce the voltage output of VCO control voltage Vcntrl (sample frequency compensation system 5).

This is because adopt when for example PWM (width modulation) exports, and need low-pass filter, thereby tracking velocity is slack-off.Can before the D/A conversion, insert low-pass filter, make VCO control voltage Vcntrl nonoscillatory, but at this moment tracking velocity be also slack-off.

Here, describe with the most basic example that is feedback controlled to, can be as long as low according to margin of error Error decision VCO control voltage, any feedback can both be used.

Fig. 4 is the key diagram that supply frequency is shown, and transverse axis express time, the longitudinal axis are represented the power supply amplitude.

When the sample frequency of AD transducer 1 was k times (the natural several times of supply frequency and 2 N power are doubly) of supply frequency, 1 voltage (AD transformed value) that is controlled to L point sampling gained was the rising zero cross point.

At this moment, if locking (electric voltage frequency no change) fully, then the AD transformed value of voltage is " 0 " at every turn.Yet, the AD transformed value when supply frequency is leading be on the occasion of, and be negative value (with reference to figure 4) when lagging.

Margin of error Error presents one by one corresponding and dull increasing in 90 degree scopes to phase differential, thereby to make the AD transformed value of the sampled point of each selection be the value of sign inversion.

But,, VCO must be controlled voltage Vcntrl and be restricted to the value that forms 1/2 times～2 sampling frequencies for the frequency of the natural several times of sample frequency or natural number/one frequency all lock.

In the invention process form 1, sample frequency is set at the natural several times of electric voltage frequency and be 2 N power doubly, thereby 1/2 times of also locking of sample frequency.Feedback quantity in the above-mentioned formula (21) " ε Error " also needs to be limited.

Here, in supply voltage zero cross point rising portion locking sample frequency, but also can at this moment adopt AD transformed value itself as margin of error Error in decline place locking.

As described above, trace into the natural several times of supply frequency by sample frequency with the AD transducer, can directly obtain higher harmonic components with Fourier transform device 3 from the Fourier transform result, thereby can be with simple structure measurement fundamental energy and higher hamonic wave electric energy.

Also can structurally make and make VCO6 and sample frequency is that several kHz, cpu clock are the situation combination of several MHz, and AD transducer 1 does not just need precision high especially, thereby chip area is little, preferable during monolithic ICization.

By VCO6 control oscillation frequency, thereby compare when directly controlling the sample frequency of AD transducer 1, can improve control accuracy, can measure the electric energy of higher hamonic wave accurately with the clock that uses CPU.

As AD transducer 1, even employing delta sigma type, also can finely tune the raising frequency sample frequency, thereby contain the measuring accuracy height of the power associated volume of electric energy by VCO6, and suitable monolithic ICization.

Such as previously discussed, the sample frequency of AD transducer 1 is set at the natural several times of supply frequency and also be 2 N power doubly, thereby from the angle of arithmetic speed, it is good that Fourier transform device 3 uses FFT.

Utilize said structure, the power associated volume of energy measurement union not in the prior arts such as each higher hamonic wave value of the phase differential of energy measurement union active power, active energy, reactive power, reactive energy, applied power, distortion power, current effective value, voltage effective value, electric current and voltage or these projects.

For example, can measure accurately and calculate the required reactive power of power-efficient, and can obtain the power factor that becomes the effective index of utilizing of power accurately to comprise the mode of higher hamonic wave.

Sample frequency compensation system 5 can realize with the calculation function of CPU, and said structure sample frequency compensation system 5 only makes up VCO6 and just can realize, thereby can make simple in structure.

Sample frequency compensation system 5 is benchmark according to the output data of AD data encapsulation apparatus 2 with zero cross point (rise or descend), locks, thereby among the CPU complex calculations does not take place, can make simple in structure.

Utilize FEEDBACK CONTROL to follow the tracks of margin of error Error in the above-mentioned formula (21), thereby tracing property is good, and real-time is superior.

Example 2

In the control of VCO6, also the first-harmonic absolute phase of FFT can be locked in same position,

Fig. 5 is the block diagram that the key component circuit composition of the invention process form 2 is shown.As the VCO control method, this illustrates the situation that the first-harmonic absolute phase of FFT is locked in same position.Among Fig. 5, the part identical with (with reference to figure 2) mentioned above marks " A " after same-sign, omits explanation.

In this case, Fourier transform device and sample frequency compensation system 5A and VCO6A connect together, form the sample frequency control device, the device that wherein comprises supply voltage absolute phase pick-up unit and lag or detect as voltage phase difference in advance with regard to absolute phase.

Sample frequency compensation system 5A is according to the data from Fourier transform device 3A, and output is to the VCO control voltage of VCO6A.

Fig. 6 is the natural number L key diagram of the compensation deals of usefulness doubly that the sample frequency with AD transducer 1A that the invention process form 2 is shown traces into supply frequency, and is identical with above-mentioned Fig. 1, Fig. 3, and the vector space that the real axis (transverse axis) and the imaginary axis (longitudinal axis) are formed is shown.

As indicated above, if the natural number L that the sample frequency of AD transducer 1A is locked as supply frequency is doubly, then power supply first-harmonic absolute phase be identical value at every turn, but supply frequency when lagging toward the direction rotation that lags, and rotate toward leading direction when leading.

With regard to the situation of following formula (22) expression, consider first-harmonic sub-value V1_cmp_pre and currency V1_cmp on the complex values after the FFT computing.

Vl_cmp_pre＝Vl_pre_re+j·Vl_pre_im (22)

V1_cmp＝V1_re+j·V1_im

At this moment, ask phase differential Phase_V1_Error with following formula (23).

$\mathrm{Phase}\_\mathrm{<figure-callout\; id="1"\; label="V"\; filenames="C0280548500251.png,C0280548500331.png"\; state="\{\{state\}\}">V</figure-callout>}1\_\mathrm{Error}$

$=\arctan \left(\frac{\mathrm{<figure-callout\; id="1"\; label="V"\; filenames="C0280548500251.png,C0280548500331.png"\; state="\{\{state\}\}">V</figure-callout>}1\_\mathrm{pre}\_\mathrm{im}\&CenterDot;\mathrm{<figure-callout\; id="1"\; label="V"\; filenames="C0280548500251.png,C0280548500331.png"\; state="\{\{state\}\}">V</figure-callout>}1\_\mathrm{re}-\mathrm{<figure-callout\; id="1"\; label="V"\; filenames="C0280548500251.png,C0280548500331.png"\; state="\{\{state\}\}">V</figure-callout>}1\_\mathrm{pre}\_\mathrm{re}\&CenterDot;\mathrm{<figure-callout\; id="1"\; label="V"\; filenames="C0280548500251.png,C0280548500331.png"\; state="\{\{state\}\}">V</figure-callout>}1\_\mathrm{<figure-callout\; id="1"\; label="im\; V"\; filenames="C0280548500251.png,C0280548500331.png"\; state="\{\{state\}\}">im</figure-callout>}}{V}\right)---\left(23\right)$

Here, the scope of phase differential Phase_V1_Error is ± 90 degree.

If voltage amplitude is the value of almost fixed at every turn, then the denominator of formula (23) can be considered constant.The molecule of formula (23) is corresponding one by one with phase differential, and dullness reduces.Therefore, making margin of error Error is the molecule of formula (23), then can represent margin of error Error with following formula (24).

Error＝V1_pre_im·V1_re-V1_pre_re·V1_im (24)

At this moment, if there is the above phase differential of ± 90 degree, then symbol is anti-phase.Owing to be locked in the natural several times or natural number/one of sample frequency, VCO need be controlled voltage Vcntrl and be restricted to the value that forms 1/2 times～2 sampling frequencies again.Feedback quantity (ε Error) also needs to be limited.

By above such composition, the invention process form also has following effect except that the effect of above-mentioned example 1 (in the rising or the decline place locking at zero point).

Promptly, the Fourier transform device is carried out the phase locking of the voltage (or electric current) after the Fourier transform (FFT is good), thereby carry out the locking phase ratio at the voltage waveform zero cross point like that with above-mentioned example 1, when white noise and higher hamonic wave stack, improve aspect the precision superior.

Example 3

Above-mentioned example 2 is not specifically spoken of the benchmark of absolute phase, but the first-harmonic absolute phase of FFT can be locked in 0 degree, 90 degree, 180 degree, 270 degree.

The following describes the VCO control method of the invention process form 3.Under this situation, the position of fixed voltage first-harmonic coordinate (the first-harmonic absolute phase of FFT) is chosen as 0 degree, 90 degree.180 degree or 270 degree.

Fig. 7 is the key diagram that the VCO control running of example 3 is shown, and is identical with Fig. 1, Fig. 3, Fig. 6, and the vector space of being made up of the real axis (transverse axis) and the imaginary axis (longitudinal axis) is shown.

At first, consider to be locked in the situation of 0 degree.

Phase lag when supply frequency lags, thus the real number value V1_im in the above-mentioned formula (2) for negative, and supply frequency when leading this real number value for just.

Real number value V1_im is corresponding one by one with phase differential and have a dull relation that increases in ± 90 degree scopes.Therefore, can represent margin of error Error with following formula (25).

Error＝-V1_im (25)

Here, identical with above-mentioned example 2, also need to limit VCO control voltage Vcntrl and feedback quantity.

Utilize the method, in the time of making the operand of margin of error Error be less than example 2, and do not need to store the coordinate of 1 (last time).

When phase differential was spent above+90, margin of error Error was not the dull relation that increases, but symbol does not change.Therefore, set margin of error Error for following formula (26), then can in ± 180 degree scopes, make margin of error Error that phase differential is the dull relation that reduces.

if?V1_re≥0

Error＝-V1_im

else?if?V1_im≥0

Error＝-(2·Vrms1-V1_im) (26)

else

Error＝-(-2·Vrms1-V1_im)

The effective value Vrms1 of voltage fundamental is almost constant usually, can be used as constant and handles.Utilize the method, can make ± the 90 feedback scopes of spending are ± 180 degree.

Be locked in 90 degree, 180 degree, 270 when spending, too can the fixed error amount.

That is, identical with above-mentioned formula (25), the margin of error Error in the time of spending with following formula (27) expression 90.

Error＝V1_re (27)

Margin of error Error in the time of spending with following formula (28) expression 180.

Error＝V1_im (28)

Margin of error Error in the time of spending with following formula (29) expression 270.

Error＝-V1_re (29)

In addition, identical with above-mentioned formula (26), the margin of error Error in the time of spending with following formula (30) expression 90.

if?V1?im≥0

Error＝V1_re

else?if?V1_re≥0

Error＝2·Vrms1-V1_re (30)

else

Error＝-2·Vrms1-V1_re

Margin of error Error in the time of spending with following formula (31) expression 180.

if?V1_re≤0

Error＝V1_im

else?if?V1_im≥0

Error＝2·Vrms1-V1_im (31)

else

Error＝-2·Vrms1-V1_im

Margin of error Error in the time of spending with following formula (32) expression 270.

if?V1_im≤0

Error＝-V1_re

else?if?V1_re≥0

Error＝-(2·Vrms1-V1_re (32)

else

Error＝-(-2·Vrms1-V1_re)

As described above, the first-harmonic absolute phase of FFT is locked in 0 degree, 90 degree, 180 degree, 270 degree, except that the effect with above-mentioned example 2, feedback expanded range that can also ± 90 degree can make the setting range increasing to ± 180 degree.

Example 4

Above-mentioned example 1～3 is not spoken of the figure place of the associated D/A transformation component of sample frequency compensation system, but the few D/A transducer of available figure place.

Fig. 8 is the block diagram that the key component circuit composition of the invention process form 4 is shown, and wherein identical with (Fig. 2, Fig. 5) mentioned above part is added " B " after with symbol, omit and describe in detail.

Among Fig. 8, sample frequency compensation system 5B related with the few D/A transducer of figure place and the outer part of VCO6B only are shown.

At this moment, sample frequency compensation system 5B has the few D/A transducer of figure place.

Insert attenuator 51 and totalizer 52 between sample frequency compensation system 5B and the VCO6B.The D/A that totalizer 52 and figure place are few is related, to set the VCO control voltage of biasing.

Totalizer 52 outputs to VCO6B with the VCO control voltage of bias voltage VOFF addition gained, makes VCO control voltage become the assigned frequency (for example 60Hz) of power supply.Thus, can make the frequency of each potential energy control of D/A transducer meticulous.

When the clock frequency of VCO6B output was big, for meticulous control sample frequency, the figure place that the D/A transducer requires was many.Therefore, when the D/A transducer was output as " 0 ", the clock frequency that is controlled to VCO6B was the assigned frequency (60Hz) of power supply.

Totalizer 52 is with bias voltage VOFF addition, and the clock frequency that makes VCO6B is the assigned frequency of power supply.

Fig. 9 is the key diagram that the control running of the invention process form 4 is shown, the relation of the output voltage of the transducer of D/A shown in it (sample frequency compensation system 5B), the output voltage of attenuator 51, VCO control voltage and bias voltage VOFF.

Illustrating as Fig. 9, is the center with bias voltage VOFF, controls the output voltage of D/A transducer, then can suppress the figure place of D/A transducer requirement, and available inexpensive and small-sized D/A transducer is measured the power associated volume accurately.

The following describes to make on the structure and can further adjust VCO control voltage condition.Figure 10 specifically illustrates the attenuator 51 among Fig. 8 and the composition frame chart of totalizer 52, makes the situation that totalizer 52 can be adjusted bias voltage VOFF shown in it on the structure.

Among Figure 10, make on attenuator 51 structures and have resistance R 1 and the variable resistor R2 that the output voltage of D/A transducer is carried out dividing potential drop,, can adjust the range of control of VCO control voltage by adjusting branch pressure voltage.

Totalizer 52 has carries out the resistance R 3 of dividing potential drop and variable resistor R4 and with branch pressure voltage (output voltage of attenuator 51) and the branch pressure voltage addition of bias voltage VOFF and the voltage adder circuit 52B of output VCO control voltage of D/A output voltage to bias voltage VOFF.

The variable adjustment part of variable resistor R2 and R4 is arranged on the outside of electronic watt-hour meter, can adjusts arbitrarily from the outside.

The structure of utilizing Figure 10 is the scope of VCO control voltage not only, and the bias voltage of actual addition, all can adjust.

The scope of VCO control voltage means the length corresponding to VCO control voltage arrow among Fig. 9, the voltage range when for example 8 D/A transducer is distributed 45Hz～66Hz.

Bias voltage VOFF is equivalent among Fig. 9 the side-play amount (reference arrow number) to 0V, at this moment can adjust arbitrarily.

That is, adjust the variable resistor R2 in the attenuator 51, then VCO controls the range of voltage, and adjusts the variable resistor R4 in the totalizer 52, and then the bias voltage of the actual input of voltage adder circuit 52B changes.

Like this, make the range of control (or amount of bias of bias voltage) of D/A transducer variable, thereby can measure the power associated volume accurately, and assigned frequency also can be tackled with inexpensive and small-sized D/A transducer when changing according to the circuit of using.

Example 5

Though above-mentioned example 2～4 is not specifically spoken of, as shown in figure 11, the electrical energy pulse output unit 7 of pulse output electric energy can be set also in the back level of power associated volume arithmetic unit 4C.

Figure 11 is the block diagram that the key component circuit composition of the invention process form 5 is shown, and the part identical with (Fig. 2, Fig. 5) mentioned above added " C " in the back of prosign, omits and describes in detail.

In this case, electrical energy pulse output unit 7 is pressed the power samples of fixed clock to the computing gained, and the horizontal pulse of going forward side by side is handled.

In the electric energy meter, require usually power pulse to be exported by the interval shorter than 1 cycle of power supply.

Existing electric energy meter directly multiplies each other electric current I and voltage V, carry out the electric energy computing, thereby satisfy above-mentioned electrical energy pulse easily and export requirement, but among the present invention, utilize the electric current and the voltage in Fourier transform (FFT) each cycle of computing, ask electric energy from this operation result, thereby the electrical energy pulse of each cycle output can not satisfy above-mentioned requirements.

For example, among Figure 11, suppose that each FFT operation result calls power associated volume arithmetic unit 4C and calculates the power that active power, reactive power, applied power etc. need.

At this moment, the supply frequency that changes is all the time kept the length in 1 cycle of power supply with each cycles such as counters, and, just can obtain electric energy (time integral value of power) the back addition of multiplying each other of this count value (1 cycle of power supply) and performance number.Yet, utilizing this computing, electrical energy pulse output unit 7 can only be exported the electrical energy pulse of each power cycle.

The following describes the running that addresses this problem and improve the invention process form 5 of the real-time when adopting Fourier transform.

The sequential chart of Figure 12 illustrates the cpu power computing and the electrical energy pulse output running of the invention process form 5.Among Figure 12, t, t+1 ... handle running each carries out data content regularly corresponding to each.

At this moment, AD transform data packaging system 2C has detection and encapsulates the function of required encapsulation time at the L point, and power associated volume arithmetic unit 4C has the function of the power of each sampling ordering calculation of output.

At first, press the timing shown in Figure 12 topmost, AD transform data packaging system 2C is recorded in the time (time of 1 cycle share) that the L point encapsulates to be needed.

Then, CPU utilizes Fourier transform device 3C that the data of encapsulation are carried out Fourier transform, and utilizes power associated volume arithmetic unit 4C computational calculation power (the 1st performance number) (with reference to the 2nd hurdle among Figure 12).At this moment, Power arithmetic each content-data on regularly lag content (with reference to the 1st hurdle) 1 cycle share on data encapsulation is handled regularly (with reference to t-1, t ...).

Secondly, will encapsulate time (writing time :) of needing on the L point and from the power (power of computing after the Fourier transform: reference the 2nd hurdle) pass to electrical energy pulse output unit 7 (with reference to the 3rd hurdle Figure 12) of above-mentioned encapsulation of data computing from power associated volume arithmetic unit 4C with reference to the 1st hurdle.

At this moment, be sent to the time (cell width on the 3rd hurdle) of electrical energy pulse output unit 7 with mode length variation writing time.Content-data in the output regularly of each power lag during than data encapsulation 2 cycle shares (with reference to t-2, t-1 ...).

CPU sampled to the power that passes to electrical energy pulse output unit 7 by the fixed cycle (fixed clock) shorter than 1 cycle of supply frequency, and the power that will at every turn sample (value on the 3rd hurdle, i.e. the 2nd power) is as electric energy addition (with reference to the 4th hurdle among Figure 12).

That is to say, in the example shown in Figure 12, have an appointment 6 times the sampling of each 1 cycle of supply frequency, to each sampling of the corresponding power output of same data encapsulation electric energy addition with identical value.

At last, when electrical energy pulse output unit 7 reaches electric energy with hope at each described electric energy additive value, output electrical energy pulse (with reference to the 5th hurdle among Figure 12).

By above such built-up circuit, the energy requirement of real time can be exported electrical energy pulse simultaneously accurately.

At this moment sampling period is short more, can make precision high more, thereby wishes the fixed cycle that (fixed clock) set shortlyer than the electrical energy pulse output cycle as far as possible.

Example 6

Though above-mentioned example 5 is not specifically spoken of, also can compensate the phase differential of the voltage and current of each higher hamonic wave.

Figure 13 is the block diagram that the invention process form 6 Key Circuit composition of the phase differential of making the voltage and current that can compensate each higher hamonic wave on the structure is shown, and the part identical with (Figure 11) mentioned above added " D " in the prosign back, omit and describe in detail.

Among Figure 13, insert phase compensation device 8 between Fourier transform device 3D and power associated volume arithmetic unit 4D, this device 8 is rotated computing by the absolute value to voltage and current, compensates the phase differential of the voltage and current of each higher hamonic wave.

Current sensor (CT etc.) and voltage sensor (PT etc.) influence the phase place of the voltage and current of unit line usually.The mimic channel that is arranged on AD transducer 1D input end also influences the phase place of voltage and current.

Therefore, for the power associated volume of correct measurement power circuit, need the above-mentioned analog circuitry system of compensation to cause the phase place of distortion.

For example, when the phase place of the voltage and current of nth harmonic has shown in Figure 1 the relation, phase differential on the power circuit is under the situation of " 0 ", can carry out the computing of voltage rotation θ-φ or the computing of electric current θ-φ, and be not ' 0 at the phase differential on the power circuit " situation under, can be rotated computing by its phase differential.

The new electric current I n_cmp_new that obtains when here, available following formula (33) expression is rotated computing to electric current.

In_cmp_new＝In_new_re+j·In_new_im (33)

At this moment by following formula (34) the electric current I n_cmp_new that can look for novelty.

$\left(\begin{array}{c}\mathrm{In}\_\mathrm{new}\_\mathrm{re}\\ \mathrm{In}\_\mathrm{new}\_\mathrm{im}\end{array}\right)=\left(\begin{array}{cc}\cos (\mathrm{\&phi;}-\mathrm{\&theta;})& -\sin (\mathrm{\&phi;}-\mathrm{\&theta;})\\ \sin (\mathrm{\&phi;}-\mathrm{\&theta;})& \cos (\mathrm{\&phi;}-\mathrm{\&theta;})\end{array}\right)\&CenterDot;\left(\begin{array}{c}\mathrm{In}\_\mathrm{re}\\ \mathrm{In}\_\mathrm{im}\end{array}\right)---\left(34\right)$

During the rated output associated volume, use new electric current I n_cmp_new.Carry out this compensation by each higher hamonic wave, accurately the rated output associated volume.

Here, select voltage or electric current as the related value of power, its absolute phase is rotated computing, to compensate each higher hamonic wave phase differential, but also can be rotated computing, at this moment also can obtain identical action effect certainly active power and the reactive power that power associated volume arithmetic unit 4D computing obtains.

Industrial practicality

As described above, according to the present invention, energy computing active power, active energy, reactive power, idle The phase difference of electric energy, apparent energy, distortion power, current effective value, voltage effective value, electric current and voltage, The power relevance quantity of the value of these each higher hamonic waves of project etc., thus to not only towards general family expenses and also towards Electronic watt-hour meter and the power relevance quantity computing circuit of demander that will manage on a time period electric energy is useful. This Outward, owing to also measure reactive energy, to not only towards power factor regulatory requirement person but also towards using inversion Electronic watt-hour meter and the power relevance quantity computing circuit of the demander of the higher hamonic waves such as device generation equipment are useful.

Claims (11)

1, a kind of electronic watt-hour meter, this electronic watt-hour meter comprises:

The measuring-signal of expression electric current of power circuit and voltage is transformed into digital value and is taken into the AD transducer of usefulness, and

The microprocessor that comprises the electric energy arithmetic unit of using according to the electric energy of the described power circuit of described digital value computing; It is characterized in that this electronic watt-hour meter also possesses:

Detect the supply frequency pick-up unit of the supply frequency of described power circuit,

Be arranged with the clock circuit branch of described microprocessor and control the sample frequency control device of the sample frequency of described AD transducer according to described supply frequency,

Make the voltage controlled oscillator of the sample frequency variation of described AD transducer corresponding to control voltage from described sample frequency control device;

Described sample frequency control device is controlled described sample frequency, and making described sample frequency is the natural several times of described supply frequency,

Described electric energy arithmetic unit comprises the higher hamonic wave operational part that computing higher hamonic wave electric energy is used.

2, electronic watt-hour meter as claimed in claim 1 is characterized in that,

Described sample frequency control device is controlled described sample frequency, and making described sample frequency is 2 n power of supply frequency, and wherein n is a natural number,

Described electric energy arithmetic unit comprises the fast Fourier transform device, utilizes fast Fourier transform computing higher hamonic wave electric energy.

3, electronic watt-hour meter as claimed in claim 1 is characterized in that,

Described AD transducer is the delta sigma type AD transducer that needs the raising frequency sampling.

4, electronic watt-hour meter as claimed in claim 1 is characterized in that,

Making described sample frequency control device on the structure comprises:

The zero cross point pick-up unit of the zero cross point that detects described supply frequency rising or descend, and

After described the supply frequency rising or decline zero cross point of last time, through the moment in 1 cycle, detect that described supply frequency lags or in advance as the power phase device for detecting difference of power phase difference from the AD transformed value of described supply frequency,

Control the sample frequency of described AD transducer according to described power phase difference.

5, electronic watt-hour meter as claimed in claim 1 is characterized in that,

Making described sample frequency control device on the structure comprises:

Detect the absolute phase pick-up unit of the voltage absolute phase of described power circuit, and

After the last time of described voltage absolute phase,, detect that described absolute phase lags or in advance as the voltage-phase device for detecting difference of voltage phase difference through the moment in 1 cycle,

Control the sample frequency of described AD transducer according to described voltage phase difference.

6, electronic watt-hour meter as claimed in claim 5 is characterized in that,

Make on the structure described voltage-phase device for detecting difference with 0 the degree, 90 the degree, 180 the degree or 270 the degree absolute phases as benchmark.

7, electronic watt-hour meter as claimed in claim 1 is characterized in that,

Make the sample frequency compensation system that described sample frequency control device has the sample frequency of the described AD transducer of compensation on the structure,

Described sample frequency compensation system comprises

Ask the controlled quentity controlled variable arithmetic unit of the controlled quentity controlled variable of described sample frequency,

The D/A converting means that the controlled quentity controlled variable of described sample frequency is exported after the D/A conversion in addition, and

Make the bias unit of the output voltage biasing of described D/A converting means,

Described bias unit makes the assigned frequency lateral deviation of described power circuit put assigned voltage.

8, electronic watt-hour meter as claimed in claim 7 is characterized in that,

Described bias unit has adjusts the bias voltage adjusting gear that described assigned voltage is used from the outside.

9, electronic watt-hour meter as claimed in claim 1 is characterized in that,

Described electric energy arithmetic unit comprises:

Encapsulate the AD transform data packaging system of voltage and current measuring-signal of 1 cycle share of described supply frequency,

The data of described AD transform data packaging system encapsulation are carried out the Power arithmetic device of Fourier transform and computing the 1st performance number,

Detect described 1 cycle share voltage of encapsulation or the encapsulation time detection device of required encapsulation time of electric current,

Keep described the 1st performance number in each described encapsulation time, the power output device of described the 1st performance number as the 2nd performance number exported in the sampling instruction of simultaneously every generation regulation execution cycle, and

The electrical energy pulse output unit of output electrical energy pulse when the aggregate-value of described the 2nd performance number of accumulative total and described the 2nd performance number reaches setting at every turn.

10, electronic watt-hour meter as claimed in claim 1 is characterized in that,

Described electric energy arithmetic unit comprises:

Encapsulate the AD transform data packaging system of voltage and current measuring-signal of 1 cycle share of described supply frequency,

Data to described AD transform data packaging system encapsulation are carried out Fourier transform, and the Power arithmetic portion of the phase differential of the power relating value of each higher hamonic wave of computing and described power relating value, and

Phase compensation device, this compensation system be by twiddle operation, makes the phase differential of described power relating value become measured side's real power relating value phase differential, and the electric current or the described voltage of described 1 cycle share is compensated.

11, a kind of power associated volume computing circuit is characterized in that, this power associated volume computing circuit comprises:

The measuring-signal of expression electric current of power circuit and voltage is transformed into digital value and is taken into the AD transducer of usefulness,

Encapsulate the AD transform data packaging system of described digital value by 1 cycle share,

The data of described AD transform data packaging system encapsulation are carried out the Fourier transform device of Fourier transform,

According to the transformation results of described Fourier transform device, the power associated volume arithmetic unit of computational calculation power associated volume,

According to the frequency of described electric current or described voltage, the sample frequency compensation system of the sample frequency compensation rate of the described AD transducer of computing, and

To output to the voltage controlled oscillator of described AD transducer with the sample frequency that described compensation rate changes.

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