CN103134969B - A kind of power factor corrector and phase voltage method of estimation - Google Patents

Abstract

The invention discloses the voltage estimation method in a kind of power factor corrector and electric system.Described power factor corrector comprises: parameter sampling circuit, for being obtained the phase voltage in each phase line of electric system and the line voltage between each phase line by sampling, is supplied to signal processing circuit; Described signal processing circuit, for determining sampling phase voltage and sample line voltage effective value according to sampling phase voltage value and sample line magnitude of voltage, and utilizes line voltage unbalance factor to calculate estimation phase voltage value in corresponding phase line according to described effective value.Scheme provided by the invention can be estimated the voltage in electric system preferably.

Description

A kind of power factor corrector and phase voltage method of estimation

Technical field

The present invention relates to power equipment and method, espespecially a kind of power factor corrector and phase voltage method of estimation.

Background technology

For the electric system of three-phase three-wire system without zero line, owing to there is no Zero potential reference in this system, therefore using the sample reference point of the artificial reference point (that is, virtual reference point) in system as actual input voltage, the tie point N of three phase voltages as shown in Figure 2.When three hot voltage effective values are balanced, each live wire is equal to each other based on the phase voltage of this virtual reference point, and measured phase voltage equals virtual voltage.

But, when on three lines, the effective value of voltage is unbalanced, the amplitude of such as input voltage is asymmetric or uneven, or input voltage harmonic wave between out of phase different time, artificial reference point there will be floating, thus different from the Zero potential reference of reality, therefore carry out voltage sample according to the artificial reference point in system and be different from virtual voltage by causing sampled phase voltage.

At present, the solution generally adopted for the problems referred to above is: utilize input three-phase transformer at secondary generation Zero potential reference, and using this Zero potential reference as system reference point.But under normal circumstances, the volume of input transformer is very large, and its cost is very important, and therefore this solution is unsatisfactory.

Summary of the invention

In view of this, the present invention proposes the voltage estimation method in a kind of power factor corrector and electric system, to estimate the voltage in electric system.

For achieving the above object, technical scheme of the present invention is specifically achieved in that

A kind of power factor corrector, comprising:

Parameter sampling circuit, is constructed by sampling and obtains the phase voltage in each phase line of electric system and the line voltage between each phase line, be supplied to signal processing circuit;

Described signal processing circuit, is configured to determine sampling phase voltage and sample line voltage effective value according to sampling phase voltage value and sample line magnitude of voltage, and utilizes the degree of unbalancedness of line voltage to calculate estimation phase voltage value in corresponding phase line according to described effective value.

Described signal processing circuit comprises: AD conversion unit and computing unit.

Wherein, described AD conversion unit is configured to sampled phase voltage and line voltage to be converted to digital signal from simulating signal, is supplied to described computing unit.

Wherein, described computing unit is configured to the effective value determining the sampling phase voltage in each phase line according to digital sample phase voltage value, determine the effective value of each sample line voltage according to digital sample line magnitude of voltage, and determine the estimation phase voltage value in each phase line according to the effective value of the sampling phase voltage in all phase lines and the effective value of all sample line voltage.

Described computing unit is configured to: according to the mean value of the effective value calculating sampling phase voltage effective value of the sampling phase voltage in all phase lines, according to the mean value of the effective value calculating sampling line voltage effective value of all sample line voltage, and determine the estimation phase voltage value in corresponding phase line according to the effective value of the mean value of sampling phase voltage effective value, the mean value of sample line voltage effective value and the sample line voltage arbitrarily between phase line.

Described computing unit is configured to: according to formula

$V_{a\_\mathrm{estim}}=(V_{a\_\mathrm{acqui}}+V_{b\_\mathrm{acqui}}+V_{c\_\mathrm{acqui}})/3-2\·\frac{V_{\mathrm{bc}\_\mathrm{acqui}}-(V_{\mathrm{ab}\_\mathrm{acqui}}+V_{\mathrm{bc}\_\mathrm{acqui}}+V_{\mathrm{ca}\_\mathrm{acqui}})/3}{(V_{\mathrm{ab}\_\mathrm{acqui}}+V_{\mathrm{bc}\_\mathrm{acqui}}+V_{\mathrm{ca}\_\mathrm{acqui}})/3}\·(V_{a\_\mathrm{acqui}}+V_{b\_\mathrm{acqui}}+V_{c\_\mathrm{acqui}})/3$

Determine the estimation phase voltage value in the first phase line; And/or according to formula

$V_{b\_\mathrm{estim}}=(V_{a\_\mathrm{acqui}}+V_{b\_\mathrm{acqui}}+V_{c\_\mathrm{acqui}})/3-2\·\frac{V_{\mathrm{ca}\_\mathrm{acqui}}-(V_{\mathrm{ab}\_\mathrm{acqui}}+V_{\mathrm{bc}\_\mathrm{acqui}}+V_{\mathrm{ca}\_\mathrm{acqui}})/3}{(V_{\mathrm{ab}\_\mathrm{acqui}}+V_{\mathrm{bc}\_\mathrm{acqui}}+V_{\mathrm{ca}\_\mathrm{acqui}})/3}\·(V_{a\_\mathrm{acqui}}+V_{b\_\mathrm{acqui}}+V_{c\_\mathrm{acqui}})/3$

Determine the estimation phase voltage value in the second phase line; And/or according to formula

$V_{c\_\mathrm{estim}}=(V_{a\_\mathrm{acqui}}+V_{b\_\mathrm{acqui}}+V_{c\_\mathrm{acqui}})/3-2\·\frac{V_{\mathrm{ab}\_\mathrm{acqui}}-(V_{\mathrm{ab}\_\mathrm{acqui}}+V_{\mathrm{bc}\_\mathrm{acqui}}+V_{\mathrm{ca}\_\mathrm{acqui}})/3}{(V_{\mathrm{ab}\_\mathrm{acqui}}+V_{\mathrm{bc}\_\mathrm{acqui}}+V_{\mathrm{ca}\_\mathrm{acqui}})/3}\·(V_{a\_\mathrm{acqui}}+V_{b\_\mathrm{acqui}}+V_{c\_\mathrm{acqui}})/3$

Determine the estimation phase voltage value on third phase line;

Wherein, Va_acqui is the effective value of the sampling phase voltage in the first phase line, and Vb_acqui is the effective value of the sampling phase voltage in the second phase line, and Vc_acqui is the effective value of the sampling phase voltage on third phase line; Vab_acqui is the effective value of the sample line voltage between the first and second phase lines, and Vbc_acqui is the effective value of the sample line voltage between second and third phase line, and Vca_acqui is the effective value of the sample line voltage between first and third phase line.

On the other hand, the voltage estimation method in a kind of electric system, comprising in the present invention:

Sampling step, obtains the phase voltage in each phase line of electric system and the line voltage between each phase line by sampling;

Calculation procedure, determines sampling phase voltage and sample line voltage effective value according to sampling phase voltage value and sample line magnitude of voltage, and utilizes the degree of unbalancedness of line voltage to calculate estimation phase voltage value in corresponding phase line according to described effective value.

Described calculation procedure comprises:

Calculate effective value, sampled phase voltage and line voltage are converted to digital signal from simulating signal, and the effective value of the sampling phase voltage in each phase line is determined according to digital sample phase voltage value, the effective value of each sample line voltage is determined according to digital sample line magnitude of voltage;

Calculate and estimate phase voltage value, determine the estimation phase voltage value in each phase line according to the effective value of the sampling phase voltage in each phase line and the effective value of all sample line voltage.

The effective phase voltage value of described calculating comprises:

According to the mean value of the effective value calculating sampling phase voltage effective value of the sampling phase voltage in all phase lines, according to the mean value of the effective value calculating sampling line voltage effective value of all sample line voltage;

The estimation phase voltage value in corresponding phase line is determined according to the effective value of the mean value of sampling phase voltage effective value, the mean value of sample line voltage effective value and the sample line voltage arbitrarily between phase line.

Described calculation procedure comprises: according to formula

$V_{a\_\mathrm{estim}}=(V_{a\_\mathrm{acqui}}+V_{b\_\mathrm{acqui}}+V_{c\_\mathrm{acqui}})/3-2\·\frac{V_{\mathrm{bc}\_\mathrm{acqui}}-(V_{\mathrm{ab}\_\mathrm{acqui}}+V_{\mathrm{bc}\_\mathrm{acqui}}+V_{\mathrm{ca}\_\mathrm{acqui}})/3}{(V_{\mathrm{ab}\_\mathrm{acqui}}+V_{\mathrm{bc}\_\mathrm{acqui}}+V_{\mathrm{ca}\_\mathrm{acqui}})/3}\·(V_{a\_\mathrm{acqui}}+V_{b\_\mathrm{acqui}}+V_{c\_\mathrm{acqui}})/3$

Determine the estimation phase voltage value in the first phase line; And/or according to formula

$V_{b\_\mathrm{estim}}=(V_{a\_\mathrm{acqui}}+V_{b\_\mathrm{acqui}}+V_{c\_\mathrm{acqui}})/3-2\·\frac{V_{\mathrm{ca}\_\mathrm{acqui}}-(V_{\mathrm{ab}\_\mathrm{acqui}}+V_{\mathrm{bc}\_\mathrm{acqui}}+V_{\mathrm{ca}\_\mathrm{acqui}})/3}{(V_{\mathrm{ab}\_\mathrm{acqui}}+V_{\mathrm{bc}\_\mathrm{acqui}}+V_{\mathrm{ca}\_\mathrm{acqui}})/3}\·(V_{a\_\mathrm{acqui}}+V_{b\_\mathrm{acqui}}+V_{c\_\mathrm{acqui}})/3$

Determine the estimation phase voltage value in the second phase line; And/or according to formula

$V_{c\_\mathrm{estim}}=(V_{a\_\mathrm{acqui}}+V_{b\_\mathrm{acqui}}+V_{c\_\mathrm{acqui}})/3-2\·\frac{V_{\mathrm{ab}\_\mathrm{acqui}}-(V_{\mathrm{ab}\_\mathrm{acqui}}+V_{\mathrm{bc}\_\mathrm{acqui}}+V_{\mathrm{ca}\_\mathrm{acqui}})/3}{(V_{\mathrm{ab}\_\mathrm{acqui}}+V_{\mathrm{bc}\_\mathrm{acqui}}+V_{\mathrm{ca}\_\mathrm{acqui}})/3}\·(V_{a\_\mathrm{acqui}}+V_{b\_\mathrm{acqui}}+V_{c\_\mathrm{acqui}})/3$

Determine the estimation phase voltage value on third phase line;

Wherein, Va_acqui is the effective value of the sampling phase voltage in the first phase line, and Vb_acqui is the effective value of the sampling phase voltage in the second phase line, and Vc_acqui is the effective value of the sampling phase voltage on third phase line; Vab_acqui is the effective value of the sample line voltage between the first and second phase lines, and Vbc_acqui is the effective value of the sample line voltage between second and third phase line, and Vca_acqui is the effective value of the sample line voltage between first and third phase line.

Therefore the voltage estimation method in the power factor corrector that the embodiment of the present invention provides and electric system can be estimated voltage preferably, thus the voltage estimated is utilized to monitor system.

Hereafter by clearly understandable mode by coming by reference to the accompanying drawings to be further described such scheme of the present invention, technical characteristic, advantage and implementation thereof to the explanation of embodiment.

Accompanying drawing explanation

Fig. 1 is the structural representation of power factor corrector in one embodiment of the invention;

Fig. 2 is the schematic diagram of phase three-wire three electric system in one embodiment of the invention, and the structure of electric resistance partial pressure sampling unit is shown;

Fig. 3 is the processing flow chart of computing unit in the present invention's specific implementation.

Particularly, the reference symbol used in above-mentioned accompanying drawing is as follows:

Fig. 1: parameter sampling circuit 101, signal processing circuit 102.

Embodiment

For making object of the present invention, technical scheme and advantage clearly understand, to develop simultaneously embodiment referring to accompanying drawing, the present invention is described in more detail.It should be noted that for the ease of understanding, in description below, disclosing many concrete details.But, it will be appreciated by those skilled in the art that some or all that realization of the present invention can not adopt in these details.Known technology does not specifically describe to avoid unnecessary obscuring.

As previously mentioned, by reference to the accompanying drawings 2, in three line three-phase electrical power systems, owing to there is no zero line, so the phase voltage on each bar line is the voltage of the reference point N of relative virtual.When the effective value of each bar line is unbalanced, this virtual reference point can be floated, and causes the phase voltage obtained not to be virtual voltage.And those skilled in the art can understand, phase voltage is the voltage of relative reference point, and line voltage is the voltage between two live wires.Therefore, the value of line voltage accurately can be obtained, even if occur that on each line, voltage effective value is unbalanced.

Further, the present inventor finds, the degree of unbalancedness of line voltage and the degree of unbalancedness of phase voltage exist approximate proportional relationship.As shown in Figure 2, in three line three-phase electrical power systems, there are three phase lines, are designated as the first phase line A, the second phase line B and third phase line C respectively.

Wherein, the phase voltage degree of unbalancedness f of the first phase line A _aand the line voltage unbalance factor f between second and third phase line B and C _bCrelation be:

f _A＝2·f _BC。

Other two phase lines also have similar relation.

And wherein V _bCthe line voltage between line B, C, V _avgLthe mean value of each line voltage, $V_{\mathrm{avgL}}=\frac{V_{\mathrm{BC}}+V_{\mathrm{AC}}+V_{\mathrm{AB}}}{3}.$

Then, $f_A=2\·\frac{V_{\mathrm{BC}}-V_{\mathrm{avgL}}}{V_{\mathrm{avgL}}}.$

Further, V _a=V _avgP-f _av _avgP, wherein v _a, V _band V _cthe phase voltage in this first, second, and third phase line respectively.

The voltage mentioned in describing above is the root mean square of the magnitude of voltage of acquisition, i.e. effective value.

Therefore, the principle of solution of the present invention is exactly the phase voltage value utilizing line magnitude of voltage correction accurately to obtain, thus obtains the phase voltage value of closely virtual voltage.

Thus, embodiments provide a kind of power factor corrector (PFC, powerfactorcorrector) voltage estimation method and in electric system, for estimating phase voltage value, obtain the estimation phase voltage value comparatively close with actual phase voltage value (or be called calculate phase voltage value).Further, even if when the unbalance condition of phase voltage worsens, the estimation phase voltage value that this power factor corrector provides is also lower compared with conventional art with the error degree of virtual voltage.Therefore, the power factor corrector utilizing the embodiment of the present invention to provide can judge the unbalance condition of three-phase input voltage, monitor better.

In an embodiment of the invention, as shown in Figure 1, a kind of power factor corrector comprises: parameter sampling circuit 101, signal processing circuit 102.Wherein, described parameter sampling circuit 101, for obtaining sampling phase voltage in electric system and/or sample line voltage, is supplied to described signal processing circuit 102.

Particularly, described parameter sampling circuit 101 comprises: electric resistance partial pressure sampling unit, amplifier difference sampling unit.In actual applications, a kind of realization of electric resistance partial pressure sampling unit as shown in Figure 2.Resistance shown in figure is used for dividing potential drop, and electric capacity is used for filtering.Amplifier difference sampling unit is used for high-voltage value to be converted to low voltage value, is supplied to described signal processing circuit 102.

Described signal processing circuit 102 is for according to sampling phase voltage value and sample line magnitude of voltage, and obtain estimating phase voltage value, this circuit can adopt digital signal processor (DSP, DigitalSignalProcessor) to realize.Particularly, described signal processing circuit 102 comprises: modulus (A/D) converting unit, computing unit.

According to above to the description of the principle of the invention, computing unit can determine the estimation phase voltage value on phase line A, B and C respectively according to following formula (1)-(3).

$V_{a\_\mathrm{estim}}=(V_{a\_\mathrm{acqui}}+V_{b\_\mathrm{acqui}}+V_{c\_\mathrm{acqui}})/3-2\·\frac{V_{\mathrm{bc}\_\mathrm{acqui}}-(V_{\mathrm{ab}\_\mathrm{acqui}}+V_{\mathrm{bc}\_\mathrm{acqui}}+V_{\mathrm{ca}\_\mathrm{acqui}})/3}{(V_{\mathrm{ab}\_\mathrm{acqui}}+V_{\mathrm{bc}\_\mathrm{acqui}}+V_{\mathrm{ca}\_\mathrm{acqui}})/3}\·(V_{a\_\mathrm{acqui}}+V_{b\_\mathrm{acqui}}+V_{c\_\mathrm{acqui}})/3---\left(1\right)$

$V_{b\_\mathrm{estim}}=(V_{a\_\mathrm{acqui}}+V_{b\_\mathrm{acqui}}+V_{c\_\mathrm{acqui}})/3-2\·\frac{V_{\mathrm{ca}\_\mathrm{acqui}}-(V_{\mathrm{ab}\_\mathrm{acqui}}+V_{\mathrm{bc}\_\mathrm{acqui}}+V_{\mathrm{ca}\_\mathrm{acqui}})/3}{(V_{\mathrm{ab}\_\mathrm{acqui}}+V_{\mathrm{bc}\_\mathrm{acqui}}+V_{\mathrm{ca}\_\mathrm{acqui}})/3}\·(V_{a\_\mathrm{acqui}}+V_{b\_\mathrm{acqui}}+V_{c\_\mathrm{acqui}})/3---\left(2\right)$

$V_{c\_\mathrm{estim}}=(V_{a\_\mathrm{acqui}}+V_{b\_\mathrm{acqui}}+V_{c\_\mathrm{acqui}})/3-2\·\frac{V_{\mathrm{ab}\_\mathrm{acqui}}-(V_{\mathrm{ab}\_\mathrm{acqui}}+V_{\mathrm{bc}\_\mathrm{acqui}}+V_{\mathrm{ca}\_\mathrm{acqui}})/3}{(V_{\mathrm{ab}\_\mathrm{acqui}}+V_{\mathrm{bc}\_\mathrm{acqui}}+V_{\mathrm{ca}\_\mathrm{acqui}})/3}\·(V_{a\_\mathrm{acqui}}+V_{b\_\mathrm{acqui}}+V_{c\_\mathrm{acqui}})/3---\left(3\right)$

In above-mentioned formula (1)-(3), Va_acqui, Vb_acqui, Vc_acqui are respectively the root mean square (RMS of A, B and C phase line up-sampling phase voltage, rootmeansquare) value (namely, effective value), Vab_acqui, Vbc_acqui, Vca_acqui are the root-mean-square value of phase line A and B, phase line B and C and the sample line voltage between phase line A and C, and Va_estim, Vb_estim, Vc_estim are respectively the estimation phase voltage value on phase line A, B, C.

As noted earlier, owing to not being connected with reference point, even if when Voltage unbalance, the phase voltage value utilizing above-mentioned parameter to calculate in three phase lines also can ensure its accuracy.

In a specific implementation, the treatment scheme of computing unit as shown in Figure 3, comprises the following steps.

Step 301: the A/D transformation result reading sampling phase voltage Va_sample, Vb_sample, Vc_sample from AD conversion unit.

Step 302: square Cumulate Sum determining the sampling phase voltage Va_sample in each phase line, Vb_sample, Vc_sample, and square Cumulate Sum of sample line voltage Vab_sample, Vbc_sample, Vca_sample between each phase line.

Wherein,

Vab_sample＝Va_sample-Vb_sample，

Vbc_sample＝Vb_sample-Vc_sample，

Vca_sample＝Vc_sample-Va_sample。

Those skilled in the art can recognize, because the phase voltage of each phase line has phase place, so account form is not above simple numerical operation, but contain the computing at phasing degree.This is the common practise of this area, repeats no more herein.

Step 303: judge whether a voltage sample period (being generally a civil power cycle) terminates, if terminated, performs step 304.Otherwise, return and perform step 301.

Step 304: calculating sampling phase voltage effective value (being also root-mean-square value) Va_acqui, Vb_acqui, Vc_acqui, and sample line voltage effective value Vab_acqui, Vbc_acqui, Vca_acqui.

Step 305: the mean value calculating three sampling phase voltage effective values, as previously mentioned,

$V_{\mathrm{avgP}}=\frac{V_{a\_\mathrm{acqui}}+V_{b\_\mathrm{acqui}}+V_{c\_\mathrm{acqui}}}{3},$

And calculate the mean value of three sample line voltage effective values, as previously mentioned,

$V_{\mathrm{avgL}}=\frac{V_{\mathrm{ab}\_\mathrm{acqui}}+V_{\mathrm{bc}\_\mathrm{acqui}}+V_{\mathrm{ac}\_\mathrm{acqui}}}{3}.$

Step 306: calculate the estimation phase voltage value V on phase line A, B and C _{a_estim}, V _{b_estim}and V _{c_estim},

$V_{a\_\mathrm{estim}}=(1-2\·\frac{V_{\mathrm{bc}\_\mathrm{acqui}}-V_{\mathrm{avgL}}}{V_{\mathrm{avgL}}})\·V_{\mathrm{avgP}},$

$V_{b\_\mathrm{estim}}=(1-2\·\frac{V_{\mathrm{ac}\_\mathrm{acqui}}-V_{\mathrm{avgL}}}{V_{\mathrm{avgL}}})\·V_{\mathrm{avgP}},$

$V_{c\_\mathrm{estim}}=(1-2\·\frac{V_{\mathrm{ab}\_\mathrm{acqui}}-V_{\mathrm{avgL}}}{V_{\mathrm{avgL}}})\·V_{\mathrm{avgP}}$

In an alternative embodiment of the invention, additionally provide the voltage estimation method in a kind of electric system, comprising:

The line voltage between the phase voltage of each phase line of electric system and each phase line is obtained by sampling;

To determine to sample according to sampling phase voltage value and sample line magnitude of voltage the effective value of phase voltage and sample line voltage, and utilize the degree of unbalancedness of line voltage to calculate estimation phase voltage value in corresponding phase line according to described effective value.It may be noted that by sampling obtain phase voltage value and line magnitude of voltage be instantaneous value.

In a specific implementation, utilize the effective value of sampling phase voltage value and sample line magnitude of voltage to calculate and estimate that the method for phase voltage value comprises:

Sampled phase voltage and line voltage are converted to digital signal from simulating signal, and determine the effective value of the sampling phase voltage in each phase line according to digital sample phase voltage value, determine the effective value of each sample line voltage according to digital sample line magnitude of voltage;

The estimation phase voltage value in each phase line is determined according to effective value Va_acqui, Vb_acqui, the Vc_acqui of the sampling phase voltage in all phase lines and effective value Vab_acqui, Vbc_acqui, Vca_acqui of all sample line voltage;

Wherein, Va_acqui is the effective value of the sampling phase voltage on phase line A, and Vb_acqui is the effective value of the sampling phase voltage on phase line B, and Vc_acqui is the effective value of the sampling phase voltage on phase line C.

Such as, computing unit in PFC can determine the estimation phase voltage value Va_estim on phase line A according to Va_acqui, Vb_acqui, Vc_acqui, Vab_acqui, Vbc_acqui, Vca_acqui, concrete treatment scheme with reference to figure 3, can repeat no more herein.

Certainly, the computing unit in PFC also can determine the estimation phase voltage value Vb_estim on phase line B or the estimation phase voltage value Vc_estim on phase line C according to Va_acqui, Vb_acqui, Vc_acqui, Vab_acqui, Vbc_acqui, Vca_acqui.

In a specific implementation, the method for the estimation phase voltage value determined in each phase line according to Va_acqui, Vb_acqui, Vc_acqui, Vab_acqui, Vbc_acqui, Vca_acqui comprises:

According to the mean value VavgP of the effective value calculating sampling phase voltage effective value of the sampling phase voltage in all phase lines, according to the mean value VavgL (see step 305) of the effective value calculating sampling line voltage effective value of all sample line voltage; The estimation phase voltage value in another phase line is determined according to the effective value of the sample line voltage between VavgP, VavgL and any two phase lines.

Such as, can determine Va_estim according to VavgP, VavgL and Vbc_acqui, step 306 just provides a kind of concrete sample calculation.

In another specific implementation, utilize the effective value of sampling phase voltage value and sample line magnitude of voltage to calculate and estimate that the method for phase voltage value comprises: according to formula

$V_{a\_\mathrm{estim}}=(V_{a\_\mathrm{acqui}}+V_{b\_\mathrm{acqui}}+V_{c\_\mathrm{acqui}})/3-2\·\frac{V_{\mathrm{bc}\_\mathrm{acqui}}-(V_{\mathrm{ab}\_\mathrm{acqui}}+V_{\mathrm{bc}\_\mathrm{acqui}}+V_{\mathrm{ca}\_\mathrm{acqui}})/3}{(V_{\mathrm{ab}\_\mathrm{acqui}}+V_{\mathrm{bc}\_\mathrm{acqui}}+V_{\mathrm{ca}\_\mathrm{acqui}})/3}\·(V_{a\_\mathrm{acqui}}+V_{b\_\mathrm{acqui}}+V_{c\_\mathrm{acqui}})/3$

Determine the estimation phase voltage value on phase line A; And/or according to formula

$V_{b\_\mathrm{estim}}=(V_{a\_\mathrm{acqui}}+V_{b\_\mathrm{acqui}}+V_{c\_\mathrm{acqui}})/3-2\·\frac{V_{\mathrm{ca}\_\mathrm{acqui}}-(V_{\mathrm{ab}\_\mathrm{acqui}}+V_{\mathrm{bc}\_\mathrm{acqui}}+V_{\mathrm{ca}\_\mathrm{acqui}})/3}{(V_{\mathrm{ab}\_\mathrm{acqui}}+V_{\mathrm{bc}\_\mathrm{acqui}}+V_{\mathrm{ca}\_\mathrm{acqui}})/3}\·(V_{a\_\mathrm{acqui}}+V_{b\_\mathrm{acqui}}+V_{c\_\mathrm{acqui}})/3$

Determine the estimation phase voltage value on phase line B; And/or according to formula

$V_{c\_\mathrm{estim}}=(V_{a\_\mathrm{acqui}}+V_{b\_\mathrm{acqui}}+V_{c\_\mathrm{acqui}})/3-2\·\frac{V_{\mathrm{ab}\_\mathrm{acqui}}-(V_{\mathrm{ab}\_\mathrm{acqui}}+V_{\mathrm{bc}\_\mathrm{acqui}}+V_{\mathrm{ca}\_\mathrm{acqui}})/3}{(V_{\mathrm{ab}\_\mathrm{acqui}}+V_{\mathrm{bc}\_\mathrm{acqui}}+V_{\mathrm{ca}\_\mathrm{acqui}})/3}\·(V_{a\_\mathrm{acqui}}+V_{b\_\mathrm{acqui}}+V_{c\_\mathrm{acqui}})/3$

Determine the estimation phase voltage value on phase line C;

Wherein, Va_acqui is the effective value of the sampling phase voltage on phase line A, and Vb_acqui is the effective value of the sampling phase voltage on phase line B, and Vc_acqui is the effective value of the sampling phase voltage on phase line C; Vab_acqui is the effective value of the sample line voltage between phase line A and B, and Vbc_acqui is the effective value of the sample line voltage between phase line B and C, and Vca_acqui is the effective value of the sample line voltage between phase line C and A.

Further, after determining estimation phase voltage value, Performance Evaluation can be carried out according to formula (4) and (5).

In a concrete example, the root-mean-square value Va=175 of actual phase voltage, Vb=220, Vc=265.The value that the power factor corrector adopting the embodiment of the present invention to provide estimates is Va_estim=176.301, error=1.301; Vb_estim=218.864, error=-1.135; Vc_estim=265.987, error=0.987.Can find out, as uneven degree (UnbalanceDegree)≤20%, error degree value (ErrorDegree)≤0.7%; Even when uneven degree arrives 50%, error degree value is also only 2%.If employing conventional art, even if when uneven degree≤20%, error degree value also > 25%.Visible, compared with conventional art, the aspect of performance that the power factor corrector that the embodiment of the present invention provides is being estimated magnitude of voltage has greatly improved.

$\mathrm{UnbalanceDegree}=|\frac{\mathrm{PhaseVoltA}}{\mathrm{PhaseVolaA}+\mathrm{PhaseVoltB}+\mathrm{PhaseVoltC}}-1|---\left(4\right)$

$\mathrm{ErrorDegree}=|\frac{\mathrm{CalculatedPhaseVoltA}}{\mathrm{Real}\mathrm{PhaseVoltA}}-1|---\left(5\right)$

Wherein, PhaseVoltA, PhaseVoltB, PhaseVoltC in formula (4) are respectively the actual phase voltage effective value on phase line A, B and C, RealPhaseVoltA in formula (5) is the actual phase voltage effective value on phase line A, and CalculatedPhaseVoltA is the estimation phase voltage effective value on phase line A.It may be noted that in the embodiment of the present invention that the estimation phase voltage calculating or determine is effective value.

In actual applications, this power factor corrector can be: phase three-wire three Vienna-Like power factor corrector, also can be the corrector of other types.It may be noted that the power factor corrector that all three-phase three-wire system electric system can adopt the embodiment of the present invention to provide and the unbalance condition of voltage estimation method to three-phase input voltage are monitored.Certainly, the electric system of other types, such as other systems without zero line also can adopt similar PFC to carry out the estimation of magnitude of voltage.

Above by drawings and Examples to invention has been detail display and explanation, but the invention is not restricted to these embodiments disclosed, other schemes that those skilled in the art therefrom derive are also within protection scope of the present invention.

Claims (8)

1. a power factor corrector, is characterized in that, comprising:

Parameter sampling circuit, is constructed by sampling and obtains the phase voltage in each phase line of electric system and the line voltage between each phase line, be supplied to signal processing circuit;

Described signal processing circuit, be configured to determine to sample according to sampling phase voltage value and sample line magnitude of voltage the effective value of phase voltage and sample line voltage, and utilize the degree of unbalancedness of line voltage to calculate estimation phase voltage value in corresponding phase line according to the effective value of described sampling phase voltage and the effective value of described sample line voltage.

2. power factor corrector according to claim 1, is characterized in that, described signal processing circuit comprises: AD conversion unit and computing unit;

Wherein, described AD conversion unit is configured to sampled phase voltage and line voltage to be converted to digital signal from simulating signal, is supplied to described computing unit;

Wherein, described computing unit is configured to the effective value determining the sampling phase voltage in each phase line according to digital sample phase voltage value, determine the effective value of each sample line voltage according to digital sample line magnitude of voltage, and determine the estimation phase voltage value in each phase line according to the effective value of the sampling phase voltage in all phase lines and the effective value of all sample line voltage.

3. power factor corrector according to claim 2, it is characterized in that, described computing unit is configured to: according to the mean value of the effective value calculating sampling phase voltage effective value of the sampling phase voltage in all phase lines, according to the mean value of the effective value calculating sampling line voltage effective value of all sample line voltage, and determine the estimation phase voltage value in corresponding phase line according to the effective value of the mean value of sampling phase voltage effective value, the mean value of sample line voltage effective value and the sample line voltage arbitrarily between phase line.

4. power factor corrector according to claim 2, is characterized in that, described computing unit is configured to according to formula

$V_{a\_estim}=(V_{a\_acqui}+V_{b\_acqui}+V_{c\_acqui})/3-2\·\frac{V_{bc\_acqui}-(V_{ab\_acqui}+V_{bc\_acqui}+V_{ca\_acqui})/3}{(V_{ab\_acqui}+V_{bc\_acqui}+V_{ca\_acqui})/3}\·(V_{a\_acqui}+V_{b\_acqui}+V_{c\_acqui})/3$

Determine the estimation phase voltage value in the first phase line; And/or according to formula

$V_{b\_estim}=(V_{a\_acqui}+V_{b\_acqui}+V_{c\_acqui})/3-2\·\frac{V_{ca\_acqui}-(V_{ab\_acqui}+V_{bc\_acqui}+V_{ca\_acqui})/3}{(V_{ab\_acqui}+V_{bc\_acqui}+V_{ca\_acqui})/3}\·(V_{a\_acqui}+V_{b\_acqui}+V_{c\_acqui})/3$

Determine the estimation phase voltage value in the second phase line; And/or according to formula

$V_{c\_estim}=(V_{a\_acqui}+V_{b\_acqui}+V_{c\_acqui})/3-2\·\frac{V_{ab\_acqui}-(V_{ab\_acqui}+V_{bc\_acqui}+V_{ca\_acqui})/3}{(V_{ab\_acqui}+V_{bc\_acqui}+V_{ca\_acqui})/3}\·(V_{a\_acqui}+V_{b\_acqui}+V_{c\_acqui})/3$

Determine the estimation phase voltage value on third phase line;

Wherein, Va_acqui is the effective value of the sampling phase voltage in the first phase line, and Vb_acqui is the effective value of the sampling phase voltage in the second phase line, and Vc_acqui is the effective value of the sampling phase voltage on third phase line; Vab_acqui is the effective value of the sample line voltage between the first and second phase lines, and Vbc_acqui is the effective value of the sample line voltage between second and third phase line, and Vca_acqui is the effective value of the sample line voltage between first and third phase line.

5. the voltage estimation method in electric system, is characterized in that, comprising:

Sampling step, obtains the phase voltage in each phase line of electric system and the line voltage between each phase line by sampling;

Calculation procedure, determine sampling phase voltage and sample line voltage effective value according to sampling phase voltage value and sample line magnitude of voltage, and utilize the degree of unbalancedness of line voltage to calculate estimation phase voltage value in corresponding phase line according to the sampling effective value of phase voltage and the effective value of described sample line voltage.

6. voltage estimation method according to claim 5, is characterized in that, described calculation procedure comprises:

Calculate effective value, sampled phase voltage and line voltage are converted to digital signal from simulating signal, and the effective value of the sampling phase voltage in each phase line is determined according to digital sample phase voltage value, the effective value of each sample line voltage is determined according to digital sample line magnitude of voltage;

Calculate and estimate that phase voltage value determines the estimation phase voltage value in each phase line according to the effective value of the effective value of the sampling phase voltage in each phase line and all sample line voltage.

7. voltage estimation method according to claim 6, is characterized in that, described calculating estimates that phase voltage value comprises:

According to the mean value of the effective value calculating sampling phase voltage effective value of the sampling phase voltage in all phase lines, according to the mean value of the effective value calculating sampling line voltage effective value of all sample line voltage;

The estimation phase voltage value in corresponding phase line is determined according to the effective value of the mean value of sampling phase voltage effective value, the mean value of sample line voltage effective value and the sample line voltage arbitrarily between phase line.

8. voltage estimation method according to claim 7, is characterized in that, described calculation procedure comprises: according to formula

$V_{a\_estim}=(V_{a\_acqui}+V_{b\_acqui}+V_{c\_acqui})/3-2\·\frac{V_{bc\_acqui}-(V_{ab\_acqui}+V_{bc\_acqui}+V_{ca\_acqui})/3}{(V_{ab\_acqui}+V_{bc\_acqui}+V_{ca\_acqui})/3}\·(V_{a\_acqui}+V_{b\_acqui}+V_{c\_acqui})/3$

Determine the estimation phase voltage value in the first phase line; And/or according to formula

$V_{b\_estim}=(V_{a\_acqui}+V_{b\_acqui}+V_{c\_acqui})/3-2\·\frac{V_{ca\_acqui}-(V_{ab\_acqui}+V_{bc\_acqui}+V_{ca\_acqui})/3}{(V_{ab\_acqui}+V_{bc\_acqui}+V_{ca\_acqui})/3}\·(V_{a\_acqui}+V_{b\_acqui}+V_{c\_acqui})/3$

Determine the estimation phase voltage value in the second phase line; And/or according to formula

$V_{c\_estim}=(V_{a\_acqui}+V_{b\_acqui}+V_{c\_acqui})/3-2\·\frac{V_{ab\_acqui}-(V_{ab\_acqui}+V_{bc\_acqui}+V_{ca\_acqui})/3}{(V_{ab\_acqui}+V_{bc\_acqui}+V_{ca\_acqui})/3}\·(V_{a\_acqui}+V_{b\_acqui}+V_{c\_acqui})/3$

Determine the estimation phase voltage value on third phase line;

Wherein, Va_acqui is the effective value of the sampling phase voltage in the first phase line, and Vb_acqui is the effective value of the sampling phase voltage in the second phase line, and Vc_acqui is the effective value of the sampling phase voltage on third phase line; Vab_acqui is the effective value of the sample line voltage between the first and second phase lines, and Vbc_acqui is the effective value of the sample line voltage between second and third phase line, and Vca_acqui is the effective value of the sample line voltage between first and third phase line.