CN101958548A - Method and system for suppressing harmonics by utilizing passive filter device - Google Patents

Method and system for suppressing harmonics by utilizing passive filter device Download PDF

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CN101958548A
CN101958548A CN2009101516399A CN200910151639A CN101958548A CN 101958548 A CN101958548 A CN 101958548A CN 2009101516399 A CN2009101516399 A CN 2009101516399A CN 200910151639 A CN200910151639 A CN 200910151639A CN 101958548 A CN101958548 A CN 101958548A
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filter
harmonic
nargin
specific times
branch
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符国录
陈阳
何新怀
倪志强
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
    • Y02E40/30—Reactive power compensation
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
    • Y02E40/40—Arrangements for reducing harmonics

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Abstract

The invention discloses a method and a system for suppressing harmonics by utilizing a passive filter device in an AC power supply system. The passive filter device comprises a plurality of filters for respectively suppressing various harmonics, and each filter comprise one or more filter branches. The method comprises the following steps of: respectively calculating the switching branch numbers of the filters for suppressing various harmonics; judging the switching branch number of a filter for suppressing one special number of harmonics among the harmonics; switching on one or more filter branches of the filter for suppressing the special number of harmonics if the switching branch number of the filter for suppressing the special number of harmonics is larger than a preset first threshold value which is larger than zero; and switching off one or more filter branches of the filter for suppressing the special number of harmonics if the switching branch number of the filter for suppressing the special number of harmonics is smaller than a preset second threshold value which is smaller than zero.

Description

Utilize passive filtration unit to suppress the method and system of harmonic wave
Technical field
The application relates to the method and system that utilizes passive filtration unit to suppress harmonic wave in the ac power supply system.
Background technology
In ac power supply system, because load can produce harmonic wave and reactive power.
Harmonic wave is caused by nonlinear load (for example direct current drive rig).When electric current is flowed through nonlinear load, can form periodically non-sinusoidal current.These periodicity non-sinusoidal currents are carried out fourier series decompose, obtaining also can obtaining the component of a series of frequencies greater than fundamental frequency outside the component identical with the AC power fundamental frequency, this part electric current just is called harmonic current.Harmonic current reduces the efficient of production, transmission and the utilization of electric energy, and the work of load is had a negative impact, and therefore need suppress harmonic current.
On the other hand, the apparent power of AC power (being rated capacity) comprises the active power and the reactive power of load.Active power refers to electric energy and is used for acting and is consumed and is converted into the electrical power of other energy (for example heat energy, luminous energy, mechanical energy or chemical energy etc.); And reactive power is to set up the electrical power that alternating magnetic field needs with the induction magnetic flux by the load of electromagnetic induction principle work.The ratio that apparent power is converted into active power and reactive power is generally determined by the characteristic of load itself.Usually, reflect the degree that the apparent power of power supply output is used effectively with power factor.Powerfactorcos is defined as follows:
cos φ = P S = P P 2 + Q 2
Wherein, P represents active power, and S represents apparent power, and Q represents reactive power.Power factor is big, represent that then the major part of apparent power is used for supplying with active power, thereby the power of power delivery is bigger.Load under normal circumstances not only will obtain active power from power supply, also needs to obtain reactive power from power supply.If load does not have enough reactive powers to set up normal electromagnetic field, then its normal operation can be affected.But the transmission of reactive power has increased the weight of the load of ac power supply circuit, and loss is increased.Therefore, reactive power compensation mechanism need be set come compensating power, with the operate as normal of proof load.
Routinely, can be with passive filter (being the LC filter) as harmonic suppression apparatus.Passive filter comprises capacitor, reactor and resistor, by the concrete parameter of capacitor and reactor is set, can obtain to suppress the filter of a certain specific times harmonic electric current.Usually, the filter that can suppress the specific times harmonic electric current can comprise one or more filter branch, and these filter branch have the setting of identical capacitor and reactor, usually, the filter branch that drops into is many more, and is strong more to the inhibitory action of the harmonic current of this specific times.If it is in parallel with the load that produces harmonic current to suppress the filter of specific times harmonic electric current, then form impedance path at this subharmonic current, this subharmonic current is produced the earial drainage effect, thereby reach the effect that suppresses this subharmonic current.On the other hand, can be capacitive for fundamental current, therefore can the reactive power of first-harmonic be compensated each filter that each times harmonic electric current suppresses respectively.
Usually, when using passive filtration unit to carry out harmonic wave inhibition and reactive power compensation, be to design according to mode at the reactive power of the filter of each harmonic electric current compensation equivalent, particularly, if judge and to carry out reactive power compensation, then progressively drop into filter branch to high order from low order.Such passive filter control method can realize good reactive power compensation effect, but the effect that suppresses harmonic wave is relatively poor.
Also there is the another kind of method of controlling passive filtration unit based on default filter branch switching order in the prior art.This method is a foundation with the harmonic characteristic of supposition, set the order of filter branch of the filter of switching specific times harmonic electric current through engineering staff's computing, judging when need carry out reactive power compensation, according to the preset order input or excise the filter branch of each filter.This method has changed the control method that progressively drops into filter branch to high order from low order, therefore can obtain harmonic suppression effect relatively preferably.But because this method is set the switching order of each time filter branch based on the harmonic characteristic of prior setting, therefore to change the effect of inhibition harmonic wave when very fast relatively poor when harmonic characteristic.
Summary of the invention
The application has proposed a kind of method and system that utilizes passive filtration unit to suppress harmonic wave in ac power supply system.
Aspect of the application, provide a kind of method of in ac power supply system, utilizing passive filtration unit to suppress harmonic wave.In this ac power supply system, passive filtration unit can comprise a plurality of filters that suppress each harmonic respectively, and each filter can comprise one or more filter branch.Described method can comprise: the throwing of the filter of calculating inhibition each harmonic respectively/cut and prop up a way; And to the throwing that suppresses the filter of a specific times harmonic in the each harmonic/cut a way to judge.If the throwing of the filter of inhibition specific times harmonic/cut a way greater than presetting first threshold then drops into one or more filter branch of the filter of described inhibition specific times harmonic, wherein said first threshold is greater than zero.If one or more filter branch of the filter of described inhibition specific times harmonic are then excised in the throwing of the filter of inhibition specific times harmonic/cut a way less than the second default threshold value, wherein said second threshold value is less than zero.
According to an embodiment, in described method, if suppress the throwing of the filter of specific times harmonic/a cut way more than or equal to described second threshold value and be less than or equal to described first threshold, then do not drop into the filter branch that does not yet excise the filter of described inhibition specific times harmonic, that is the current filter branch configuration that, keeps the filter of this specific times harmonic of inhibition.
According to another embodiment, in described method, if suppress the throwing of the filter of specific times harmonic/a cut way more than or equal to described second threshold value and be less than or equal to described first threshold, whether the nargin of filter that then can judge described inhibition specific times harmonic is less than default nargin threshold value, if then drop into a filter branch.
According to another embodiment, in described method, if suppress the throwing of the filter of specific times harmonic/a cut way more than or equal to described second threshold value and be less than or equal to described first threshold, whether the actual overcurrent multiple of filter that then can judge described inhibition specific times harmonic is less than default overcurrent threshold value, if then excise a filter branch.
According to another embodiment, after dropping into or excising one or more filter branch, described method can further comprise: when the actual current of the filter that suppresses specific times harmonic during greater than the maximum operating currenbt of the expectation of the filter of this inhibitions specific times harmonic, carry out one of them of following three kinds of operations at random: drop into a filter branch, excise a filter branch and do not drop into also not surgical filtering branch road.
According to another embodiment, if suppress the throwing of the filter of each specific times harmonic/cut branch road number average more than or equal to described second threshold value and be less than or equal to described first threshold, and the nargin of filter that suppresses each specific times harmonic is all more than or equal to default nargin threshold value, and then described method can further comprise: the idle requirement of calculating described ac power supply system; If described idle requirement less than default idle requirement first threshold, is then excised a filter branch of the filter of nargin maximum; If described idle requirement greater than default idle requirement second threshold value, then drops into a filter branch of the filter of nargin minimum.
In the application on the other hand, provide a kind of system that in ac power supply system, utilizes passive filtration unit to suppress harmonic wave.In this system, passive filtration unit can comprise a plurality of filters that suppress each harmonic respectively, and each filter can comprise one or more filter branch.Described system can comprise: throw/cut a way computing unit, the throwing of the filter of calculating inhibition each harmonic respectively/cut and prop up a way; Throw/cut a way comparing unit, to the throwing that suppresses the filter of a specific times harmonic in the each harmonic/cut a way to compare with the presetting first threshold and second threshold value, wherein, described first threshold is greater than zero, and described second threshold value is less than zero; And first processing unit, according to described throwing/cut the result of a way comparing unit, drop into or excise one or more filter branch of the filter of described inhibition specific times harmonic.
According to an embodiment, described system can further comprise: the nargin computing unit, and calculating suppresses the nargin of the filter of each harmonic respectively; The nargin comparing unit, the nargin of the filter of the inhibition specific times harmonic that described nargin computing unit is calculated and default nargin threshold; And second processing unit, according to described throwing/cut the result of a way comparing unit and described nargin comparing unit, drop into a filter branch of the filter of described inhibition specific times harmonic.
According to another embodiment, described system can further comprise: actual overcurrent multiple computing unit, and calculating suppresses the actual overcurrent multiple of the filter of each harmonic respectively; Actual overcurrent multiple comparing unit, the actual overcurrent multiple of the filter of the inhibition specific times harmonic that described actual overcurrent multiple computing unit is calculated and default overcurrent threshold; And the 3rd processing unit, according to described throwing/cut the result of a way comparing unit and described actual overcurrent multiple comparing unit, excise a filter branch of the filter of described inhibition specific times harmonic.
According to another embodiment, described system can further comprise: the resonance judging unit, and whether the actual current that judge to suppress the filter of specific times harmonic suppresses the maximum operating currenbt of expectation of the filter of specific times harmonic greater than this; And the random process unit, according to the judged result of resonance judging unit, carry out one of them of following three kinds of operations at random: drop into a filter branch, a filter branch of excision and do not drop into also not surgical filtering branch road.
According to another embodiment, described system can further comprise: the nargin computing unit, and calculating suppresses the nargin of the filter of each harmonic respectively; The nargin comparing unit, the nargin of the filter of the inhibition specific times harmonic that described nargin computing unit is calculated and default nargin threshold; Idle requirement computing unit calculates the idle requirement of described ac power supply system; Idle requirement comparing unit is with described idle requirement the computing unit idle requirement that calculates and idle requirement first threshold and idle requirement second threshold preset; And manage the unit everywhere, according to the result of described throwing/cut way comparing unit, described nargin comparing unit and a described idle requirement comparing unit, a filter branch of the filter of excision nargin maximum or drop into a filter branch of the filter of nargin minimum.
According to the application, in ac power supply system, utilize passive filtration unit to suppress in the method and system of harmonic wave, suppress the throwing of the filter of specific times harmonic/cut a way can calculate by following formula:
k = ( I N + I N h ) / I N e
Wherein, k represents the throwing of the filter of described inhibition specific times harmonic/cut a way, I NThe actual current of representing the filter of described inhibition specific times harmonic,
Figure B2009101516399D0000052
The harmonic current of the described specific times of the ac power supply system that expression measures, The maximum operating currenbt of representing the expectation of single filter branch in the filter of described inhibition specific times harmonic.
According to the application, in ac power supply system, utilize passive filtration unit to suppress in the method and system of harmonic wave, suppress the nargin of the filter of specific times harmonic and can calculate by following formula:
μ = n ( I N e - I N n ) / I N e
Wherein, μ represents the nargin of the filter of described inhibition specific times harmonic, and n represents the quantity of the filter branch that the filter of described inhibition specific times harmonic has dropped into, The maximum operating currenbt of representing the expectation of single filter branch in the filter of described inhibition specific times harmonic,
Figure B2009101516399D0000056
The actual measurement electric current of representing the single filter branch that the filter of described inhibition specific times harmonic has dropped into.
According to the application, in ac power supply system, utilize passive filtration unit to suppress in the method and system of harmonic wave, the actual overcurrent multiple that suppresses the filter of specific times harmonic can calculate by following formula:
E = I N n / I N e
Wherein, E represents the actual overcurrent multiple of the filter of described inhibition specific times harmonic, The actual measurement electric current of representing the single filter branch that dropped in the filter of described inhibition specific times harmonic, The maximum operating currenbt of representing the expectation of single filter branch in the filter of described inhibition specific times harmonic.
Description of drawings
The passive filtration unit that utilizes that Fig. 1 shows according to an embodiment of the application suppresses the harmonic circuit schematic diagram;
The passive filtration unit that utilizes that Fig. 2 shows according to first embodiment of an aspect of the application suppresses the flow chart of the method for harmonic wave;
The passive filtration unit that utilizes that Fig. 3 shows according to second embodiment of an aspect of the application suppresses the flow chart of the method for harmonic wave;
The passive filtration unit that utilizes that Fig. 4 shows according to the 3rd embodiment of an aspect of the application suppresses the flow chart of the method for harmonic wave;
Fig. 5 shows the flow chart of the method for avoiding the resonance phenomena that method may occur shown in Fig. 2～4;
The passive filtration unit that utilizes that Fig. 6 shows according to the 4th embodiment of an aspect of the application suppresses the flow chart of the method for harmonic wave and compensating power;
The passive filtration unit that utilizes that Fig. 7 shows according to the application's first embodiment on the other hand suppresses the block diagram of the system of harmonic wave;
The passive filtration unit that utilizes that Fig. 8 shows according to the application's second embodiment on the other hand suppresses the block diagram of the system of harmonic wave;
The passive filtration unit that utilizes that Fig. 9 shows according to the application's the 3rd embodiment on the other hand suppresses the block diagram of the system of harmonic wave;
Figure 10 shows the block diagram that can avoid the module of resonance phenomena in system shown in Fig. 7～9; And
The passive filtration unit that utilizes that Figure 11 shows according to the application's the 4th embodiment on the other hand suppresses the block diagram of the system of harmonic wave and compensating power.
Embodiment
Be appreciated that loaded line comprises the harmonic current of a plurality of different number of times usually, in order to suppress the each harmonic electric current respectively, the filter that suppresses the each harmonic electric current respectively can be set in the ac power supply system for the nonlinear load power supply.In this application, the filter that suppresses the each harmonic electric current is referred to as passive filtration unit.Concise and to the point for what describe, mainly, the method for utilizing passive filtration unit to carry out the harmonic wave inhibition is described to be example at the filter of N subharmonic current (below be called " N filter ", N can be 3,5,7 etc.).Those skilled in the art can expect that described harmonic suppressing method at N filter can expand to other filter.
At first with reference to Fig. 1, describe according to an embodiment of the application, utilize passive filtration unit to suppress the harmonic circuit schematic diagram.
Provide for load 20 among the embodiment of electrical power in AC power shown in Figure 1 10,, therefore in ac power supply system, can produce harmonic current because load 20 is non-linear.Exemplarily show the N subharmonic current among Fig. 1
Figure B2009101516399D0000071
In order to suppress the N subharmonic current, N the filter 30 in parallel with load 20 can be set, this N time filter can comprise one or more filter branch (not shown)s that identical capacitor and reactor are provided with that have.For the needs of describing, the quantity of the filter branch that N filter can be dropped into is called the branch road sum m of N filter.The quantity n that is appreciated that the filter branch that has dropped into of N filter should be less than or equal to m.Actual current for each filter branch that has dropped into of measuring N time filter 30
Figure B2009101516399D0000072
The galvanometer (not shown) can be set in each filter branch.For this exemplary, because being provided with of each filter branch of N filter 30 is identical, thereby the actual current of each filter branch
Figure B2009101516399D0000073
Also identical.In addition, according to concrete setting, each filter branch that has dropped into of N filter 30 can have the maximum operating currenbt of expectation
Figure B2009101516399D0000074
In order to ensure operate as normal, the actual current of filter branch should be greater than the maximum operating currenbt of expectation.Therefore similarly, because that each filter branch is provided with is identical, can have the maximum operating currenbt of identical expectation.The maximum operating currenbt of the expectation of filter branch can be the rated current (by the concrete parameter decision of each composed component of filter branch) of this branch road and the product of specified overcurrent multiple.For example, according to national standard (GB50227-95, Code for design of installation of shunt capacitors), the effective value that flows through the fundamental current of capacitor and harmonic current should not surpass 1.3 times (that is, specified overcurrent multiple is 1.3) of rated current.
With reference to Fig. 2, the method for utilizing passive filtration unit inhibition harmonic wave according to first embodiment of an aspect of the application is described below.Can judge whether to carry out the input or the excision operation of filter branch, thereby can suppress harmonic wave by the pre-if parameter that records according to the method for this embodiment according to actual conditions.At first, according to utilizing passive filtration unit to suppress the parameter of harmonic circuit, calculate the filter branch number (being designated hereinafter simply as " throwing/cut a way ") that needs input or excision.Then, according to the throwing that obtains/a cut way, determine whether to need to drop into or the surgical filtering branch road by judgement.To describe this method in detail below.
With circuit shown in Figure 1 is example, and the filter branch that has dropped into according to N filter 30 is counted n and the actual current of each filter branch of recording
Figure B2009101516399D0000081
Can calculate the actual current of filter
Figure B2009101516399D0000082
Then, according to the actual current I of N filter N, the N subharmonic current in the ac power supply system that measures And the maximum operating currenbt of the expectation of the single filter branch in N filter
Figure B2009101516399D0000084
Can calculate the throwing of N filter/cut a way k by following formula (1) N:
k N = ( I N + I N h ) / I N e - - - ( 1 )
Be appreciated that as the throwing that obtains according to formula (1)/cut a way k NGreater than 0 o'clock, represent that N filter is not enough to the inhibition dynamics of N subharmonic current, need to drop into k NIndividual filter branch; On the other hand, as the throwing that obtains according to formula (1)/cut a way k NLess than 0 o'clock, represent N filter inhibition ability surplus to the N subharmonic, can excise | k N| individual filter branch.Certainly, if throw/cut a way k NEqual 0, can represent that N filter is suitable just to the inhibition of N subharmonic at this moment, needn't carry out the input or the excision operation of filter branch.
Therefore, can calculate according to formula (1) and throw/cut a way k N(step S201), the quantity of coming the filter branch of definite N filter that needs input or excise.In theory, need only | k N| ≠ 0, then expression need drop into or the operation of surgical filtering branch road.But in actual applications, as long as within the acceptable range, even throw/cut a way k to the inhibition ability of N subharmonic NBe not 0, can drop into or the operation of surgical filtering branch road yet, but keep current state.For this reason, can set in advance the first threshold k that throws/cut a way 1With the second threshold value k 2, wherein, k 1Greater than 0, k 2Less than 0.When judging k by comparing (step S202) N＞k 1The time, can be N filter and drop into a filter branch (step S203).If through relatively judging k N≤ k 1The time, then further judge k NWith k 2Relation, if judge k at step S204 N＜k 2The time, then can be a filter excision filter branch (step S205) N time.In addition, if k 2≤ k N≤ k 1, representing that the filter branch number that present N filter comprise is more satisfactory, needn't drop into or the operation of surgical filtering branch road.It will be understood by those skilled in the art that and to select suitable first threshold k according to the actual conditions of nonlinear load 1With the second threshold value k 2As a non-limiting specific embodiment, k 1=0.5, k 2=-1, certainly, other threshold value setting can also be arranged.In addition,, it may occur to persons skilled in the art that though be that example is described once to drop into or to excise a filter branch, if calculate | k N|＞2, then expression needs to drop into or at least 2 filter branch of excision, then also can once drop into or excise the filter branch more than 2 or 2 this moment.
Suppress in the method for harmonic wave, at the passive filtration unit of describing according to Fig. 2 that utilizes at k 2≤ k N≤ k 1Situation under, will keep N the current filter branch setting of filter, and not drop into or the operation of surgical filtering branch road.With reference to Fig. 3 and Fig. 4, be described in k below 2≤ k N≤ k 1Situation under, on the basis of method shown in Figure 2, can further be provided with and drop into or the judgement parameter of surgical filtering branch road, whether to drop into or the decision operation of surgical filtering branch road, suppress effect thereby obtain better harmonic current.
As shown in Figure 3, work as k 2≤ k N≤ k 1When (that is, having obtained the judgement of "No") at step S204 shown in Figure 2, can be further nargin μ by N filter NDetermine whether to carry out the input operation of filter branch.Wherein, the nargin μ of N filter NIt can be nargin (that is each filter branch actual current, of each filter branch of having dropped into of N filter
Figure B2009101516399D0000091
Maximum operating currenbt with expectation
Figure B2009101516399D0000092
Poor) summation.Particularly, nargin μ NCan be as giving a definition:
μ N = n ( I N e - I N n ) / I N e - - - ( 2 )
Wherein, n represents the filter branch number that N filter dropped into.Work as k 2≤ k N≤ k 1The time, if judge 0＜k N≤ k 1(step S301) can further judge nargin μ NWhether less than default nargin threshold value μ Threshlod(step S302), if, then can think each filter branch overload operation of filter N time, its inhibition dynamics for the N subharmonic current is not enough, therefore can drop into a filter branch (step S303) again.As a non-limiting specific embodiment, nargin threshold value μ ThreshlodCan be set to 0 or-0.2.
As shown in Figure 4, work as k 2≤ k N≤ k 1When (that is, having obtained the judgement of "No"), if k at step S204 shown in Figure 2 2≤ k N＜0 (step S401) can be according to the actual overcurrent multiple E of N the single filter branch of filter NFurther judge whether to carry out the excision operation of filter branch.The actual overcurrent multiple E of single filter branch NCan be according to the actual current of this branch road
Figure B2009101516399D0000101
Maximum operating currenbt with its expectation
Figure B2009101516399D0000102
Calculate:
E N = I N n / I N e - - - ( 3 )
At this moment, overcurrent threshold value E can be set Threshold, with the actual overcurrent multiple E of N the single filter branch of filter NWith overcurrent threshold value E ThresholdCompare (step S402), if actual overcurrent multiple E NLess than overcurrent threshold value E Threshold, can think that then N filter dropped into too much filter branch for the inhibition of N subharmonic, at this moment, can excise a filter branch (step S403).Overcurrent threshold value E ThresholdCan be according to the incompatible setting of concrete applied field, as a non-limiting specific embodiment, overcurrent threshold value E ThresholdCan be set to 0.5 or 0.6.
It will be understood by those skilled in the art that and can be on the basis of method shown in Figure 2 carry out inhibition in conjunction with Fig. 3 and process shown in Figure 4 simultaneously the N subharmonic, that is, and when in step shown in Figure 2, judging k 2≤ k N≤ k 1The time, further judge whether to satisfy 0＜k N≤ k 1If, then according to nargin μ NWith nargin threshold value μ Threshlodrelatively determine whether to drop into a filter branch; If not, then according to the actual overcurrent multiple E of single filter branch NWith overcurrent threshold value E Thresholdrelatively determine whether to excise a filter branch.
It will be understood by those skilled in the art that in the above in the execution of the method for describing with reference to Fig. 2～4,, may form resonance phenomena along with at the filter input of each harmonic electric current or the operation of surgical filtering branch road.When producing resonance, can cause ac power supply system overvoltage and overcurrent within the specific limits, load is caused adverse effect.
For this reason, the application proposes a kind of by dropping at random or surgical filtering branch road (also can be described as " fuzzy switching ") is avoided the method for the problems referred to above.Below with reference to Fig. 5, be that example is described this method with the resonance that occurs the N subharmonic in the ac power supply system.Be appreciated that, the resonance that occurs the N subharmonic in the ac power supply system can cause the actual current of N filter very big, the maximum operating currenbt sum (abbreviating " maximum operating currenbt of the expectation of N filter " in this application as) of the expectation of whole filter branch that may can drop into greater than N filter.For example, if the default filter branch of N filter adds up to m, then the maximum operating currenbt of the expectation of N filter can be the maximum operating currenbt of the expectation of single filter branch
Figure B2009101516399D0000104
Product with m.In this case, whether the actual current of judging N filter is greater than the maximum operating currenbt (step S501) of the expectation of N filter, if then can show the resonance that has produced the N subharmonic in the ac power supply system.At this moment, if drop into or the control of surgical filtering branch road according to the method shown in Fig. 2,3 or 4, then appear at the state of the N subharmonic resonance before operation is got back to again afterwards several times possibly, cause " endless loop " appearred in the control flow of N filter.For fear of the problems referred to above, can be when judging the resonance that produces the N subharmonic, (step S502) carried out in a kind of operation of random choose in three kinds of operations of filter branch of input, filter branch of excision and maintenance current state (that is, neither dropping into also not surgical filtering branch road).It will be appreciated by those skilled in the art that by such control mode, when resonance appears in ac power supply system, can withdraw from above-mentioned endless loop state quickly.
Be to be that example is described above with N filter at the N subharmonic current, in the actual ac power supply system of harmonic current with a plurality of different number of times, can according to method discussed above, respectively the each harmonic electric current be suppressed at the harmonic current of each number of times.
In addition, what method discussed above was primarily aimed at is the situation that harmonic current constantly changes, be appreciated that when the filter at the each harmonic electric current all reaches desirable holddown to this subharmonic, can further consider the measure that the reactive power in the ac power supply system is compensated.Specifically describe below with reference to Fig. 6.When in step S601, judging: at the throwing of the filter of each harmonic electric current/cut a way between first threshold k 1With the second threshold value k 2Between (that is, having obtained the judgement of "No" at step S204 shown in Figure 2), and all be not less than nargin threshold value μ at the nargin of the filter of each harmonic electric current Threshlod(that is, having obtained the judgement of "No" at step S302 shown in Figure 3) then can be thought in whole ac power supply system, and the inhibition of each harmonic electric current is all reached comparatively ideal state.At this moment, can determine whether and the filter branch of each filter to be dropped into or excise, to carry out the adjusting of reactive power compensation aspect further according to the idle requirement of ac power supply system.Particularly, can obtain idle requirement Q in the ac power supply system by measurements and calculations, and idle requirement first threshold A and the idle requirement second threshold value B are set.When in step S602, judging idle requirement Q less than idle requirement first threshold A, can represent compensation surplus, then can excise a filter branch (step S603) of the filter of nargin maximum (promptly abundant relatively) the inhibition of harmonic current to the reactive power of ac power supply system; On the other hand, as idle requirement Q in step S604 during greater than the idle requirement second threshold value B, can represent and need the reactive power of ac power supply system be compensated, then can drop into a filter branch (step S605) of the filter of the nargin minimum inhibition relative deficiency of harmonic current (promptly to).Here, can idle requirement first threshold A and the idle requirement second threshold value B be set according to concrete application scenario (for example reactive power compensation capacity of the filter branch of each filter), for example, A can be 8Kvar, and B can be 15Kvar.Be appreciated that by above mode, can take into account reactive power compensation and harmonic current preferably and suppress.
With reference to Fig. 7～Figure 11, describe according to the application's passive filtration unit that in ac power supply system, utilizes on the other hand and suppress the system of harmonic wave below.
As shown in Figure 7, according to the application on the other hand the system 1000 that in ac power supply system, utilizes passive filtration unit to suppress harmonic wave of first embodiment can comprise and throw/cut a way computing unit 1001, throw/cut a way comparing unit 1002 and first processing unit 1003.Throw/cut a way computing unit 1001 and can calculate the throwing that suppresses the filter of each harmonic in the ac power supply system/a cut way respectively.Throw/cut a way computing unit 1001 and calculate the throwing of the filter that suppresses each harmonic/cut after the way, by throwing/cut a way comparing unit 1002, the throwing of the filter of certain specific times harmonic/cut a way and presetting first threshold and second threshold value to compare will be suppressed.Suppress the throwing of the filter of this subharmonic/cut a way greater than first threshold if throw/cut the result of way comparing unit and be, then first processing unit 1003 can drop into one or more filter branch of the filter that suppresses this subharmonic; Suppress the throwing of the filter of this subharmonic/cut a way less than second threshold value if throw/cut the result of way comparing unit and be, then first processing unit 1003 can excise one or more filter branch of the filter that suppresses this subharmonic.Be appreciated that as the result that throw/cut a way comparing unit and suppress the throwing of the filter of this subharmonic/cut a way between the first threshold and second threshold value, then first processing unit can not drop into or excise operation.The calculating of the throwing of filter described herein/a cut way and the setting of first and second threshold values are identical with description above, repeat no more herein.
As shown in Figure 8, except unit shown in Figure 7, the system 1000 ' that utilizes passive filtration unit to suppress harmonic wave can further comprise nargin computing unit 1004, nargin comparing unit 1005 and second processing unit 1006.Nargin computing unit 1004 can calculate the nargin of the filter that suppresses each harmonic.The nargin of the filter of the inhibition specific times harmonic that nargin comparing unit 1005 can calculate nargin computing unit 1005 and default nargin threshold.Then, second processing unit 1006 can drop into a filter branch of the filter that suppresses this subharmonic according to the comparative result of throwing/cut a way comparing unit 1002 and nargin comparing unit 1005.Particularly, judge the throwing of the filter that suppresses specific times harmonic/a cut way greater than zero and be less than or equal to first threshold when throwing/cutting way comparing unit 1002 places, and the nargin of judging the filter that suppresses this subharmonic at nargin comparing unit 1005 places is during less than the nargin threshold value, and second processing unit 1006 can drop into a filter branch of the filter that suppresses this subharmonic.Be appreciated that when throwing/cutting the comparative result that props up way comparing unit 1002 and nargin comparing unit 1005 to be different from situation described above, then second processing unit 1006 does not drop into operation.The setting of the calculating of the nargin of filter described herein, nargin threshold value is identical with description above, repeats no more herein.
Fig. 9 shows another kind and utilizes passive filtration unit to suppress the modification of the system of harmonic wave.Except unit shown in Figure 7, the system 1000 shown in Fig. 9 " can comprise actual overcurrent multiple computing unit 1007, actual overcurrent multiple comparing unit 1008 and the 3rd processing unit 1009.Actual overcurrent multiple computing unit 1007 can calculate the actual overcurrent multiple of the filter that suppresses each harmonic, afterwards, the actual overcurrent multiple of the filter of the inhibition specific times harmonic that can will calculate by actual overcurrent multiple comparing unit 1008 and default overcurrent threshold.Then, the 3rd processing unit 1009 can be according to the result who throws/cut a way comparing unit 1002 and actual overcurrent multiple comparing unit 1008, and excision suppresses a filter branch of the filter of specific times harmonic.Particularly, judge the throwing of the filter that suppresses specific times harmonic/cut a way when throwing/cutting way comparing unit 1002 places more than or equal to second threshold value and less than zero, and the actual overcurrent multiple of judging the filter that suppresses this subharmonic at actual overcurrent multiple comparing unit 1008 places is during less than the overcurrent threshold value, and the 3rd processing unit 1009 can excise a filter branch of the filter that suppresses this subharmonic.Be appreciated that when throwing/cutting the comparative result that props up way comparing unit 1002 and actual overcurrent multiple comparing unit 1008 places to be different from situation described above, then the 3rd processing unit 1009 does not excise operation.Equally, being provided with of the calculating of the actual overcurrent multiple of filter described herein and actual overcurrent multiple threshold value is all identical with description above, repeats no more herein.In addition, it will be appreciated by those skilled in the art that, module 1007～1009 shown in Figure 9 suppresses in the system of harmonic wave with the passive filtration unit that utilizes that module 1004～1006 shown in Figure 8 can all be included in as shown in Figure 7, that is, the system that utilizes passive filtration unit to suppress harmonic wave can comprise module 1001～1009.
When first, second and/or the 3rd processing unit in the system shown in Fig. 7～9 had carried out the operation of input or surgical filtering branch road, resonance phenomena as described above may appear in the ac power supply system.For this reason, according to an embodiment, can in the system that utilizes passive filtration unit inhibition harmonic wave, further comprise resonance processing module 1200.
As shown in figure 10, resonance processing module 1200 comprises resonance judging unit 1201 and random process unit 1202.Whether the actual current that resonance judging unit 1201 can be judged the filter that suppresses specific times harmonic is greater than the maximum operating currenbt of the expectation of the filter that suppresses this subharmonic, if, then random process unit 1202 can drop into a filter branch, a filter branch of excision and not drop into also and carry out a kind of operation at random in the not surgical filtering branch road, if not, then random process unit 1202 is not operated.Here, the actual current that suppresses the filter of specific times harmonic is the actual current sum that suppresses the filter branch that the filter of this subharmonic dropped into, and the maximum operating currenbt of expectation that suppresses the filter of this subharmonic then is the maximum operating currenbt sum that suppresses the expectation of the filter branch that the filter of this subharmonic can drop into.Above this is gone through, here for briefly no longer describing in detail of describing.
As shown in figure 11, the system that utilizes passive filtration unit to suppress harmonic wave also can further comprise reactive power compensation mechanism 1400.Reactive power compensation mechanism 1400 can comprise nargin computing unit 1401, nargin comparing unit 1402, idle requirement computing unit 1403, idle requirement comparing unit 1404 and is managed unit 1405 everywhere, wherein, nargin computing unit 1401 can be respectively with identical with nargin comparing unit 1005 with reference to the nargin computing unit 1004 in the system 1000 ' shown in Figure 8 with nargin comparing unit 1402, promptly, nargin computing unit 1401 can calculate the nargin of the filter that suppresses each harmonic respectively, and the nargin of the filter of the inhibition specific times harmonic that nargin comparing unit 1402 can calculate nargin computing unit 1401 and default nargin threshold.In addition, idle requirement computing unit 1403 can calculate the idle requirement in the ac power supply system, and idle requirement comparing unit 1402 can be with the idle requirement and default idle requirement first threshold and idle requirement second threshold that calculates.The setting means of the calculating of the idle requirement here and idle requirement first threshold and idle requirement second threshold value with above describe identical, in order briefly to repeat no more.As shown in figure 11, the manages unit 1405 everywhere will be according to throwing/cut a way comparing unit 1002 (for the purpose of briefly, Figure 11 only shows and throws/cuts and prop up a way comparing unit 1002, but it will be understood by those skilled in the art that system 1000 " ' in also can comprise as shown in Figure 7 throwing/cut a way computing unit 1001 and first processing unit 1003 at least), the result of nargin comparing unit 1402 and idle requirement comparing unit 1404 handles.Particularly, judge the throwing of the filter that suppresses each harmonic/cut branch road number average more than or equal to second threshold value and be less than or equal to first threshold when throwing/cut a way comparing unit 1002, and the nargin that nargin comparing unit 1402 is judged the filter that suppresses each harmonic is during all greater than default nargin threshold value: if idle requirement comparing unit 1404 is judged idle requirement less than default idle requirement first threshold, and the filter branch managing the filter of unit 1405 excision nargin maximums everywhere then; In addition, if idle requirement comparing unit 1404 is judged idle requirement greater than default idle requirement second threshold value, then the manage the filter branch that unit 1405 drops into the filter of nargin minimums everywhere.Be appreciated that when the comparative result of throwing/cutting way comparing unit 1002, nargin comparing unit 1402 and idle requirement comparing unit 1404 places is different from situation described above the manages unit 1405 does not everywhere operate.By reactive power compensation mechanism 1400, can under the prerequisite that harmonic current is suppressed, take into account compensation to reactive power.
Abovely be described with reference to the exemplary execution mode of accompanying drawing to the application.It should be appreciated by those skilled in the art that above-mentioned execution mode only is for illustrative purposes and the example of being lifted, rather than be used for limiting.All the application instruction and the claim protection range under done any modification, be equal to replacement etc., all should be included in the claimed scope of the application.

Claims (11)

1. method of in ac power supply system, utilizing passive filtration unit to suppress harmonic wave, described passive filtration unit comprises a plurality of filters that suppress each harmonic respectively, and described each filter comprises one or more filter branch, and described method comprises:
The throwing of the filter of calculating inhibition each harmonic respectively/cut and prop up a way; And
To the throwing that suppresses the filter of a specific times harmonic in the each harmonic/cut a way to judge:
If the throwing of the filter of inhibition specific times harmonic/cut a way greater than presetting first threshold then drops into one or more filter branch of the filter of described inhibition specific times harmonic, wherein said first threshold is greater than zero; And
If one or more filter branch of the filter of described inhibition specific times harmonic are then excised in the throwing of the filter of inhibition specific times harmonic/cut a way less than the second default threshold value, wherein said second threshold value is less than zero.
2. the method for claim 1, further comprise, if suppress the throwing of the filter of specific times harmonic/a cut way more than or equal to described second threshold value and be less than or equal to described first threshold, then do not drop into the filter branch that does not also excise the filter of described inhibition specific times harmonic.
3. the method for claim 1, further comprise, if suppress the throwing of the filter of specific times harmonic/a cut way more than or equal to described second threshold value and be less than or equal to described first threshold, whether the nargin of filter of then judging described inhibition specific times harmonic is less than default nargin threshold value, if then drop into a filter branch.
4. the method for claim 1, further comprise, if suppress the throwing of the filter of specific times harmonic/a cut way more than or equal to described second threshold value and be less than or equal to described first threshold, whether the actual overcurrent multiple of filter of then judging described inhibition specific times harmonic is less than default overcurrent threshold value, if then excise a filter branch.
5. the described method of arbitrary as described above claim, wherein, after dropping into or excising one or more filter branch, described method further comprises:
When the actual current of the filter that suppresses specific times harmonic suppresses the maximum operating currenbt of expectation of filter of specific times harmonic greater than this, carry out one of them of following three kinds of operations at random: drops into a filter branch, excise a filter branch and do not drop into also not surgical filtering branch road.
6. as each described method in the claim 1 to 4, wherein, if suppress the throwing of the filter of each specific times harmonic/cut branch road number average more than or equal to described second threshold value and be less than or equal to described first threshold, and the nargin of filter that suppresses each specific times harmonic is all more than or equal to default nargin threshold value, and then described method further comprises:
Calculate the idle requirement of described ac power supply system;
If described idle requirement less than default idle requirement first threshold, is then excised a filter branch of the filter of nargin maximum;
If described idle requirement greater than default idle requirement second threshold value, then drops into a filter branch of the filter of nargin minimum.
7. system that in ac power supply system, utilizes passive filtration unit to suppress harmonic wave, described passive filtration unit comprises a plurality of filters that suppress each harmonic respectively, and described each filter comprises one or more filter branch, and described system comprises:
Throw/cut a way computing unit, the throwing of the filter of calculating inhibition each harmonic respectively/cut and prop up a way;
Throw/cut a way comparing unit, to the throwing that suppresses the filter of a specific times harmonic in the each harmonic/cut a way to compare with the presetting first threshold and second threshold value, wherein, described first threshold is greater than zero, and described second threshold value is less than zero; And
First processing unit according to the result of described throwing/cut a way comparing unit, drops into or excises one or more filter branch of the filter of described inhibition specific times harmonic.
8. system as claimed in claim 7 further comprises:
The nargin computing unit, calculating suppresses the nargin of the filter of each harmonic respectively;
The nargin comparing unit, the nargin of the filter of the inhibition specific times harmonic that described nargin computing unit is calculated and default nargin threshold; And
Second processing unit according to the result of described throwing/cut a way comparing unit and described nargin comparing unit, drops into a filter branch of the filter of described inhibition specific times harmonic.
9. system as claimed in claim 7 further comprises:
Actual overcurrent multiple computing unit, calculating suppresses the actual overcurrent multiple of the filter of each harmonic respectively;
Actual overcurrent multiple comparing unit, the actual overcurrent multiple of the filter of the inhibition specific times harmonic that described actual overcurrent multiple computing unit is calculated and default overcurrent threshold; And
The 3rd processing unit according to the result of described throwing/cut a way comparing unit and described actual overcurrent multiple comparing unit, excises a filter branch of the filter of described inhibition specific times harmonic.
10. as each described system in the claim 7 to 9, further comprise:
The resonance judging unit, whether the actual current that judge to suppress the filter of specific times harmonic suppresses the maximum operating currenbt of expectation of the filter of specific times harmonic greater than this; And
One of them of following three kinds of operations according to the judged result of resonance judging unit, carried out: drop into a filter branch, a filter branch of excision and do not drop into also not surgical filtering branch road at random in the random process unit.
11. system as claimed in claim 7 further comprises:
The nargin computing unit, calculating suppresses the nargin of the filter of each harmonic respectively;
The nargin comparing unit, the nargin of the filter of the inhibition specific times harmonic that described nargin computing unit is calculated and default nargin threshold;
Idle requirement computing unit calculates the idle requirement of described ac power supply system;
Idle requirement comparing unit is with described idle requirement the computing unit idle requirement that calculates and idle requirement first threshold and idle requirement second threshold preset; And
The manages the unit everywhere, according to described throwing/the cut result of way comparing unit, described nargin comparing unit and described idle requirement comparing unit, and a filter branch of the filter of excision nargin maximum or drop into a filter branch of the filter of nargin minimum.
CN2009101516399A 2009-07-20 2009-07-20 Method and system for suppressing harmonics by utilizing passive filter device Pending CN101958548A (en)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102684205A (en) * 2012-05-21 2012-09-19 南京理工大学 Harmonic reactive compensation control method based on current harmonic on-line estimation
CN106602576A (en) * 2017-03-03 2017-04-26 国家电网公司 Voltage reactive control system and control method based on static reactive voltage compensation
CN109638845A (en) * 2018-12-26 2019-04-16 浙江大学 Transmission line of electricity switching assembled scheme method for building up and device
CN114156891A (en) * 2021-12-14 2022-03-08 海南电网有限责任公司 Ultrahigh harmonic compensation control method

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102684205A (en) * 2012-05-21 2012-09-19 南京理工大学 Harmonic reactive compensation control method based on current harmonic on-line estimation
CN106602576A (en) * 2017-03-03 2017-04-26 国家电网公司 Voltage reactive control system and control method based on static reactive voltage compensation
CN106602576B (en) * 2017-03-03 2019-09-13 国家电网公司 Voltage powerless control system and control method based on static reactive voltage compensation
CN109638845A (en) * 2018-12-26 2019-04-16 浙江大学 Transmission line of electricity switching assembled scheme method for building up and device
CN114156891A (en) * 2021-12-14 2022-03-08 海南电网有限责任公司 Ultrahigh harmonic compensation control method
CN114156891B (en) * 2021-12-14 2024-04-09 海南电网有限责任公司 Ultra-high harmonic compensation control method

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