CN107241028A - A kind of inverter parallel droop control method virtualized based on electricity - Google Patents
A kind of inverter parallel droop control method virtualized based on electricity Download PDFInfo
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- CN107241028A CN107241028A CN201710448990.9A CN201710448990A CN107241028A CN 107241028 A CN107241028 A CN 107241028A CN 201710448990 A CN201710448990 A CN 201710448990A CN 107241028 A CN107241028 A CN 107241028A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
- H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
- H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
- H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M7/493—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode the static converters being arranged for operation in parallel
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/381—Dispersed generators
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Abstract
The invention belongs to power electronics control technology, it is related to the droop control technology in parallel of inverter in off-network type low pressure micro-capacitance sensor.A kind of inverter parallel droop control method virtualized based on electricity, is comprised the following steps：Step 1, the information of voltage that every inverter of being sampled in every shunt chopper exit is exportedAnd current informationStep 2, according to droop control equation set in advance, the active-power P and reactive power Q exported with reference to every inverter obtains the voltage reference value U of every inverter output voltageoref；Step 3, electricity virtualization is carried out to branch road where every inverter；Step 4, by the revised current reference value I of current inner loop in step 3LrefActual inductive current I with flowing through filter inductanceLIt is compared, obtains corresponding modulated signal；Step 5, the modulated signal in step 4 and carrier signal are compared, obtain the PWM trigger signals of every inverter；PWM trigger signals drive corresponding device for power switching, export target voltage.
Description
Technical field
The invention belongs to power electronics control technology, it is related to a kind of inverter parallel droop control virtualized based on electricity
Method.
Background technology
Micro-capacitance sensor can be achieved off-network with being incorporated into the power networks, possess fine development in future as effective supplement of bulk power grid
Prospect.In micro-capacitance sensor, each distributed power source powers to the load usually through inverter.In the first stage of construction of micro-capacitance sensor, power supply holds
Amount and loading demand are smaller, can meet the power demand of system only with separate unit Large Copacity inverter sometimes, but with electricity
Source is extended and load increase, is only just seemed meeting the method for system power demand by improving the capacity of single inverter and is not sounded feasible
Border.Therefore, the parallel control technology of inverter is just increasingly becoming focus of concern.
In the inverter parallel system of low pressure micro-capacitance sensor, each inverter is directed to low-voltage circuit frequently with droop control
The characteristics of in resistive, resistive droop control is frequently as prioritizing selection.For inverter parallel system, how system is realized
Accurate distribution of the power between each inverter is the key issue of research.
In practice, the line length of each inverter leg is often different, so that corresponding line impedance is also different, this will
There is difference between the Equivalent conjunction impedance for making each inverter, and the resistance difference is exactly often to cause system power assignment accuracy low
Under main cause.To change the Equivalent conjunction impedance of inverter, frequently with traditional series connection virtual impedance method, but it ought use
During this method, extra voltage loss link is introduced into, the external characteristics of inverter output voltage is softened, system electricity is in turn resulted in
Press the deterioration of quality.
The content of the invention
It is an object of the present invention to propose a kind of inverter parallel droop control method virtualized based on electricity, use
Electricity virtual method, by equally introducing parallel virtual resistance in inverter leg, so as to reach change inverter etc.
The purpose of effect connection impedance；With reference to rational parameter setting, while realizing that system power is accurately distributed, system has also been taken into account
Quality of voltage.
To achieve the above object, the present invention is achieved through the following technical solutions：
A kind of inverter parallel droop control method virtualized based on electricity, is comprised the following steps：
Step 1, the information of voltage that every inverter of being sampled in every shunt chopper exit is exportedAnd current informationFormula is calculated according to active power and reactive power calculates formula and obtains the wattful power that every inverter is supplied to common load
Rate P and reactive power Q；
Step 2, according to droop control equation set in advance, the active-power P that is exported with reference to every inverter and idle
Power Q, obtains the voltage reference value U of every inverter output voltageoref.Described voltage reference value UorefBy amplitude reference value
UrefWith frequency reference frefComposition, by amplitude reference value UrefWith frequency reference frefAccording to formula Uoref=Urefsin2π
frefT carries out voltage synthesis, obtains the voltage reference value U of every inverter output voltageoref, wherein, t is the time；
Step 3, electricity virtualization is carried out to branch road where every inverter, the electricity virtualization is exactly traditional inverse
It is improved on the basis of change device voltage x current double -loop control link, detailed process is as follows：By the every inversion produced in step 2
The reference voltage U of deviceorefAs the outer voltage reference value of every contravarianter voltage double current loop modulation link, and with every it is inverse
Become the virtual voltage U in device exitoIt is compared, the voltage deviation signal U after comparingoref- UoRatio product through outer voltage
After sub-controller, the electric current initial reference value I of current inner loop is obtained* Lref；Virtual voltage proportionality coefficient kvirIt is multiplied by inverter outlet
The virtual voltage U at placeoAfterwards, the virtual circuit voltage at virtual circuit impedance two ends is obtained, virtual circuit voltage is set again divided by advance
Fixed parallel virtual resistance Rvir, obtain the virtual current I of virtual parallel resistance branchvir, virtual current IvirWith current inner loop
Electric current initial reference value I* LrefAfter addition, the revised current reference value I of current inner loop is obtainedLref；
Step 4, by the revised current reference value I of current inner loop in step 3LrefActual inductance with flowing through filter inductance
Electric current ILIt is compared, the current deviation signal I obtained after subtracting each otherLref- ILAfter the proportional controller of current inner loop, phase is obtained
The modulated signal answered；
Step 5, the modulated signal in step 4 and carrier signal are compared, obtain the PWM triggering letters of every inverter
Number；PWM trigger signals drive corresponding device for power switching, make every inverter output target voltage.
In step 3, virtual voltage proportionality coefficient kvirIt is to be obtained by the virtual voltage proportionate relationship in virtual circuit,
K can be just obtained after having to pass through electricity virtualizationvirValue, and electricity virtualization is this method premised on electric current is equivalent
It is modified by the actual output current to inverter, so as to realize the change to inverter Equivalent conjunction impedance.
The invention has the advantages that：Because traditional series connection virtual impedance method can not take into account the power point of system simultaneously
With precision and quality of voltage, electricity virtual method proposed by the present invention utilizes control device, equally introduces parallel virtual electricity
Branch road is hindered, with reference to rational parameter setting, not only can easily change the Equivalent conjunction impedance of inverter, and do not increase additionally
The voltage loss of adding system, while realizing that system power is accurately distributed, can also take into account the quality of voltage of system.
Brief description of the drawings
It is common to same load supplying after two capacity identical inverter parallels when Fig. 1 is micro-capacitance sensor off-grid operation
Simplified electrical circuit diagram；
Fig. 2 is simplify control block diagram when single inverter uses droop control；
Fig. 3 is the schematic diagram that electricity virtualization is carried out to rectangular broken line inframe partial circuit in Fig. 2；
Fig. 4 is that parallel virtual resistance R is equally introduced on the basis of electricity virtual methodvirAfterwards, contravarianter voltage electricity
Flow the control block diagram of double -loop control link；
Fig. 5 is total equivalent virtual circuit impedance ZpWith added parallel virtual resistance RvirSituation of change；
Fig. 6 is in the voltage x current double -loop control link of inverter, when the ratio system in current inner loop proportional controller
Number kipDuring change, inverter internal impedance Z (s) Bode diagram；
Fig. 7 is in the voltage x current double -loop control link of inverter, when the ratio in outer voltage pi controller
Example coefficient kvpDuring change, inverter internal impedance Z (s) Bode diagram；
Fig. 8 is the product in outer voltage pi controller in the voltage x current double -loop control link of inverter
Divide coefficient kviDuring change, inverter internal impedance Z (s) Bode diagram；
Fig. 9 is in the voltage x current double -loop control link of inverter, as virtual voltage proportionality coefficient kvirIt is inverse during change
Become device internal impedance Z (s) Bode diagram；
Figure 10 is voltage transmission letter after all control parameters in contravarianter voltage double current loop modulation link are selected
Number G (s) Bode diagram；
Figure 11 be two capacity identical inverters after LC filter filterings, it is being powered jointly to common load and
Join system model；
Figure 12 be when be respectively adopted traditional series connection virtual impedance method and the present invention carried electricity virtual method when,
The virtual value of virtual voltage changes with time situation at 1st inverter outlet；
Figure 13 is to use traditional series connection virtual impedance method, and when adding less series connection virtual resistance, system has
The distribution condition of work(power and reactive power between two shunt choppers；
Figure 14 is to use traditional series connection virtual impedance method, when adding larger series connection virtual resistance, and system has
The distribution condition of work(power and reactive power between two shunt choppers；
Figure 15 is when using electricity virtual method of the present invention, the active power and reactive power of system at two simultaneously
Join the distribution condition between inverter.
Embodiment
Further describe the present invention with reference to the accompanying drawings and detailed description.
During low pressure micro-capacitance sensor off-grid operation, using after two capacity identical inverter parallels it is common to same load supplying as
Example, its simplification circuit is as shown in Figure 1.Wherein, ZtotalIt is common load impedance；Zn∠θn=Rn+jXn(n represents inverter
Numbering, n=1 or 2) be n-th inverter Equivalent conjunction impedance (Zn∠θnInternal impedance and circuit resistance including n-th inverter
Anti- two parts)；Un∠φunIt is the virtual voltage at n-th inverter outlet；Ion∠φinIt is the negative of n-th inverter output
Carry electric current；Uz0 ° of ∠ is common load terminal voltage.
The complex power S of n-th inverter outputnFor：
P in formula (1)nIt is the Q in the active power of n-th inverter output, formula (1)nIt is n-th inverter output
Reactive power, the active-power P of n-th inverter output can be obtained by formula (1)nAnd reactive power QnRespectively：
Still by taking n-th inverter leg as an example, because in low pressure micro-capacitance sensor, the resistance components of line impedance are dominant, then
θn≈0°；In addition, the voltage phase angle φ of n-th inverter output voltageunIt is very small, then sin φun≈φun.Therefore, n-th
The active-power P of inverter outputnAnd reactive power QnIt is represented by：
It can be seen that, when the Equivalent conjunction impedance of n-th inverter is in resistive, that is, work as Zn∠θn≈RnWhen, n-th inversion
The active-power P of device outputnAnd reactive power QnWill respectively with voltage magnitude UnWith voltage phase angle φunIt is associated, therefore, it can adopt
With active power-voltage magnitude, the resistive droop control of reactive power-voltage phase angle, but in view of at the beginning of inverter output voltage
The acquisition of phase angle is more difficult, therefore, for reactive power, can use the sagging mode of reactive power-frequency.
Fig. 2 is system simplify control block diagram when single inverter uses droop control, wherein, L, C are respectively LC filtering
The filter inductance and filter capacitor of device, UdcFor DC bus-bar voltage, UinvFor inverter end voltage, UoAt inverter outlet
Virtual voltage, UzFor load terminal voltage, ILFor inductive current, ICFor capacitance current, IoFor load current, ZloadFor single inverter
Equivalent load impedance, ZlineFor line impedance.
In fig. 2, inverter can produce the outer voltage ginseng of voltage x current double -loop control link according to droop control equation
Value is examined, and voltage x current double -loop control link to the virtual voltage at inverter outlet by being adjusted, so as to realize to inverse
The active power and reactive power for becoming device output are controlled.
The voltage x current double -loop control link of inverter is typically made up of outer voltage and current inner loop, and outer voltage is used
Pi controller, can be achieved the accurate control to inverter output voltage, and current inner loop adoption rate controller can suppress
The resonance spikes of LC wave filters, and electricity virtual method of the present invention is substantially exactly by the voltage x current to inverter
Double -loop control link is improved to realize.
Using comprising the following steps that during electricity virtual method of the present invention：
Step 1, sampled in the exit of every inverter its output information of voltage and current information, calculating obtain every
Active power and reactive power that inverter is supplied to common load；
Step 2, every inverter is according to power droop characteristic equation set in advance, with reference to having that every inverter is exported
Work(power P and reactive power Q, obtain the voltage magnitude reference value and frequency reference of virtual voltage at every inverter outlet.
Power droop characteristic equation is accordingly：
Uref=U0-mPP (6)
fref=f0+mQQ (7)
Wherein, UrefIt is the amplitude reference value of virtual voltage at inverter outlet, frefIt is virtual voltage at inverter outlet
Frequency reference, U0It is the voltage magnitude of the inverter exit virtual voltage under idle condition, f0It is in idle condition subinverse
Become the frequency of device exit virtual voltage, mPIt is the sagging coefficient of active power, mQIt is the sagging coefficient of reactive power.
frefWith UrefCarry out after voltage synthesis, virtual voltage U at inverter outletoReference voltage be：
Uoref=Urefsin2πfreft (8)
Step 3, electricity virtualization is carried out to the partial circuit in Fig. 2 in rectangular broken line square frame, corresponding electricity virtualization
Process is as shown in Figure 3.It is actual circuit in Fig. 3, on the left of arrow, arrow right side is correspondence virtual circuit,For dummy line roadlock
It is anti-,To flow throughVirtual current,For infinitely great virtual resistance,Respectively flow through
Virtual current,For dummy load impedance,To flow throughVirtual current.
When load changing, compared to virtual voltage U at inverter outletoThe small range change of generation, load current IoCan
Preferably reflect inverter output power situation of change, therefore, electricity virtualization be it is equal with actual current in virtual current,
Carried out under the equivalent constraint of electric current.
Under the equivalent constraint of electric current, as practical impedance Zline、ZloadDuring change,It will press respectivelyRelation be changed；Meanwhile, becauseResistance value for infinity, thenIt is zero,The purpose that electricity is virtualized in Fig. 3 is to set up relevant voltage, electric current between two circuits
And the corresponding relation of element, so as to which respective fictional voltage, virtual current are introduced into the Guaranteed of actual inverter.
Using electricity virtual method, the voltage x current double -loop control link to inverter is improved, equally introduced
Parallel virtual resistance RvirBranch road, the control block diagram of the voltage x current double -loop control link after improvement are as shown in figure 4, wherein, solid line
To be not introduced into parallel virtual resistance RvirBefore, it is combined using respective fictional voltage, virtual current with virtual voltage, actual current
When control block diagram, dotted line for introduce parallel virtual resistance link.Gv(s) it is contravarianter voltage double current loop modulation link
Outer voltage controller, Gi(s) be contravarianter voltage double current loop modulation link current inner loop controller, wherein, Gv(s)=
kvp+kvi/ s, Gi(s)=kipkPWM, kipFor the current ratio coefficient of current inner loop controller, kvpFor the electricity of outer voltage controller
Press proportionality coefficient, kviFor the voltage integrating meter coefficient of outer voltage controller, kPWMFor inverter equivalent gain, kvirFor virtual voltage
Proportionality coefficient, IvirTo flow through parallel virtual resistance RvirThe virtual current of branch road, I* LrefForReference value, I* Lref
It is the electric current initial reference value of current inner loop, ILrefFor IC+IoReference value, ILrefIt is also the revised electric current ginseng of current inner loop
Examine value ILref, UorefFor UoReference value.
In Fig. 4, UorefAs the outer voltage reference value of contravarianter voltage double current loop modulation link, it goes out with inverter
Virtual voltage U at mouthfuloIt is compared, the voltage deviation signal U after comparingoref- UoProportional plus integral control through outer voltage
After device, the electric current initial reference value I of current inner loop is obtained* Lref；
Analyzed jointly with reference to Fig. 2, Fig. 3 and Fig. 4, be not introduced into parallel virtual resistance RvirBefore, becauseIt is believed that voltage
Outer shroud deviation signal Uoref- UoThrough Gv(s) produce afterwardsForReference value, nowI* Lref=ILref.For different branch, line impedance ZlineDifference is there may be, therefore
Load current I in each inverter legoMay be unequal, and then correspondinglyAlso it is different.
As the parallel virtual resistance R in Fig. 4 shown in introducing dotted linevirAfter link, because of virtual voltage proportionality coefficient kvirFor void
Intend line impedanceThe virtual voltage at two ends and the virtual voltage U at inverter outletoRatio, this is equivalent in virtual electricity
Virtual circuit impedance in roadThe in parallel impedance value in two ends be RvirVirtual resistance or willR is changed intovir, and flow through
RvirVirtual current IvirBy the actual current I of the filtered inductance of convection currentLReference value ILrefPressure amendment is carried out, makes ILref=
I* Lref+Ivir, now, Equivalent to changing inverter indirectly
Equivalent conjunction impedance.
Step 4, by the current reference value I in step 3LrefActual current I with flowing through filter inductanceLIt is compared, compares
The current deviation signal I obtained afterwardsLref-ILAfter the proportional controller of current inner loop, corresponding modulated signal is obtained；
In inverter parallel system, if in line impedance ZlineIntroduced in different each inverter legs it is equal and
Join virtual resistance Rvir, it is apparent from through analysis：As parallel virtual resistance Rvir, can according to the characteristics of virtual parallel circuit when sufficiently small
Think the virtual circuit total impedance Z of each inverter legpClose to equal, its value is about Rvir, and still in resistive, meet it is resistive under
The impedance conditions hung down when controlling；Meanwhile, the actual loading electric current I in each inverter legoWill be because of above-mentioned pressure correcting action
Close to equal, and then reduce the difference between each inverter Equivalent conjunction impedance.
It is dominant in view of resistance in low-voltage circuit, if line resistance is Rline, then | Zline|≈Rline, correspond to virtual electricity
Lu ZhongyouAs addition parallel virtual resistance RvirAfterwards, the virtual circuit total impedance Z of inverter legpWith added parallel connection
Virtual resistance RvirSituation of change as shown in figure 5, whereinRespectively 0.1 Ω, 0.15 Ω, 0.3 Ω and 0.5 Ω,It can be seen that, as parallel virtual resistance RvirTake 0.1 times of minimum wire resistance in each circuit, i.e. 0.01 Ω
When, the Z of each inverter legpClose to equal, and it is 0.01 Ω or so, therefore, parallel virtual resistance RvirValue can be by each inverse
Become 0.1 times of selection of minimum wire resistance in device branch road.
In Fig. 4, most critical be how determine virtual voltage proportionality coefficient kvirValue, in being simplify control, Fig. 4
KvirDesirable steady state value, its value can carry out rough calculation by formula (9)：
By taking the circuit in Fig. 1 as an example, if the equiva lent impedance of known common load is Ztotal, then in the ideal case, every
The equivalent load impedance that inverter undertakes is Zload=2Ztotal, correspond to has in each virtual tributaryThus just
The k in each inverter leg can be calculated respectively according to formula (9)vir。
But in practice, load may change, the k in formula (9)virIt should change therewith, if continuing using constant
kvir, the impedance ratio relation in virtual circuit after matched load change is will be unable to, is ultimately caused under system power assignment accuracy
Drop.For the problem, adaptive k can be usedvirTo solve.
Formula (10) is adaptive kvirCalculation formula, wherein, UorefFor U in Fig. 4oReference value, its value is with each inversion
P and Q in device droop control equation are adjusted in real time.After load changes, kvirIt will change therewith, and when system is entered
When entering stable state, it is believed that Uoref=Uo, now, kvirUoref=kvirUo=IoZp=IvirRvir, therefore, determined using formula (10)
kvirValue feasible system real-time accurate control.Note, formula has complex operation in (10), but because of φiIt is smaller, and RvirIt is right
The change of phase angle is also very limited, is simplify control, can be by kvirTake amplitude computing.
Can obtain inverter output voltage by Fig. 4 is：
Δ=LCRvirs3+kipkPWMCRvirs2+(kipkPWMkvpRvir+Rvir-kipkPWMkvir)s+kipkPWMkviRvir
(12)
Formula (11) can be write as
Uo(s)=G (s) Uoref(s)-Z(s)Io(s)
(13)
Wherein
Z (s) is the internal impedance of inverter, but due to the Z in formula (10)pBy line impedance ZlineTake into account, phase
It has been integrated into when in by line impedance by control device among the internal impedance of inverter, therefore, it is also contemplated that Z (s) is inversion
The Equivalent conjunction impedance of device.It can see by formula (15), in selected sufficiently small RvirAfterwards, Z (s) and inverter other controls
Parameter is also relevant, to realize resistive droop control, and Z (s) should be in resistive in power frequency, and Fig. 6-Fig. 9 is respectively kip、kvp、kviAnd
kvirZ (s) Bode diagram during change.
As seen from Figure 6, k is worked asipIn interior change in a big way, Z (s), substantially in resistive, works as k in power frequency sectionipMore
When big, the tracking velocity of system is faster, but excessive kipIt is unfavorable for system stable, therefore, kipElect 0.31 as.
In Fig. 7, work as kvpDuring increase, resistive frequency bands of the Z (s) near power frequency will broaden, but excessive kvpIt will make Z's (s)
High band tends to perception, is unfavorable for the suppression of high-frequency harmonic, therefore, kvpValue should not be excessive；In addition, too small kvpZ will be made
(s) amplitude increase, and then increase the voltage loss of system, therefore, select kvpFor 1.06.
In Fig. 8, kviMore hour, the wider but too small k of resistive frequency ranges of the Z (s) near power frequencyviThe voltage of system will be made
Tracking accuracy is deteriorated, and therefore, selects kviFor 0.5.
When using adaptive virtual voltage proportionality coefficient kvirWhen, kvirIt will change with the change of load, can be with by Fig. 9
See, Z (s) resistive frequency band and amplitude be not substantially by kvirInfluence, therefore, using adaptive kvirStill it is feasible.
When all control parameters select after, by Figure 10 it can be seen that, near power frequency, voltage transfering function G (s) width
Value error and phase angle error are approximately zero, meet design requirement.
Step 5, the modulated signal produced in step 4 and carrier signal are compared, obtain the PWM triggering letters of inverter
Number；PWM trigger signals drive corresponding device for power switching, inverter is exported target voltage.
To verify the validity of electricity virtual method of the present invention, as shown in figure 11 two have been built in MATLAB
Platform capacity identical inverter is after LC filter filterings, the parallel system model powered jointly to common load.Wherein,
ZlineiThe line impedance of branch road, Z where i-th invertertotalFor common load impedance, UinviFor the end of i-th inverter
Voltage (i=1 or 2), UoiFor the virtual voltage at i-th inverter outlet, UzFor common load terminal voltage, Li、CiRespectively
The filter inductance and filter capacitor of LC wave filters, I in i platform inverter legsLiTo flow through LiInductive current, ICiTo flow through Ci's
Capacitance current, IoiFor the load current of i-th inverter output.Z is set in emulationline1=0.1+j0.013 Ω, Zline2=
0.17+j0.022 Ω, meanwhile, conventional serial virtual impedance method is respectively adopted and electricity of the present invention is virtual for ease of comparing
Change method (introduced parallel virtual resistance Rvir=0.01 Ω) when inverter output voltage situation of change, should reduce active
Influence of the power vs. voltage amplitude droop characteristic to each inverter output voltage, therefore, to active sagging Coefficient mPIt is configured
When, it have selected less value.
0 between 1s, common load Ztotal=6.661+j1.998 Ω；
Load is uprushed during 1s, and common load is incorporated to 16.754+j11.178 Ω.
Traditional series connection virtual impedance method is respectively adopted and electricity virtual method of the present invention carries out simulation comparison,
As a result as shown in Figure 12-Figure 15.
Figure 12 for when two methods are respectively adopted, at the 1st inverter outlet the virtual value of virtual voltage with the time change
Change situation, wherein, the virtual value of virtual voltage is at any time when curve 1 is using electricity virtual method, at the 1st inverter outlet
Between situation of change, curve 2,3 be using traditional series connection virtual impedance method when, be separately added into less series connection virtual resistance
During with adding larger series connection virtual resistance, the virtual value of virtual voltage changes with time situation at the 1st inverter outlet.
It can be seen that, curve 1,2,3 there occurs different degrees of decline after load is uprushed, but the voltage fall of curve 1 is small
In the voltage fall of curve 2,3.
Figure 13 is adds during less series connection virtual resistance, and the active power and reactive power of system are in two parallel inverters
Distribution condition between device.It can be seen that, when adding less series connection virtual resistance, the difference between each inverter Equivalent conjunction impedance
Different still more apparent, therefore, the assignment accuracy of system power is relatively low.
Figure 14 is adds during larger series connection virtual resistance, and the active power and reactive power of system are in two parallel inverters
Distribution condition between device.It can be seen that, when adding larger series connection virtual resistance, due between each inverter Equivalent conjunction impedance
Difference reduce, therefore, the assignment accuracy of system power is improved.
When Figure 15 is using electricity virtual method of the present invention, the active power and reactive power of system at two simultaneously
Join the distribution condition between inverter.It can be seen that, due to virtual voltage proportionality coefficient kvirIt can meet in real time in each inverter leg
Virtual impedance than relation, therefore, ZpDo not occur significant change before and after load is uprushed, and due to the parallel virtual electricity of introducing
Hinder RvirIt is sufficiently small, make the Equivalent conjunction impedance of each inverter close to equal, and still meeting the sagging control of power decoupled in resistive
While processed, the accurate distribution of system power is also achieved.
It is different from traditional series connection virtual impedance method, electricity virtual method proposed by the present invention：Equivalent in electric current
Under constraint, from the angle of control, parallel virtual resistance is equally introduced in each shunt chopper branch road, it is convenient to change
Become the Equivalent conjunction impedance of each shunt chopper, and be not introduced into extra voltage loss link, realizing that system power accurately divides
With while, also taken into account the quality of voltage of system.
Claims (2)
1. a kind of inverter parallel droop control method virtualized based on electricity, it is characterised in that comprise the following steps：
Step 1, the information of voltage that every inverter of being sampled in every shunt chopper exit is exportedAnd current informationRoot
According to active power calculate formula and reactive power calculate formula obtain active-power P that every inverter supplies to common load and
Reactive power Q；
Step 2, according to droop control equation set in advance, the active-power P and reactive power exported with reference to every inverter
Q, obtains the voltage reference value U of every inverter output voltageoref, described voltage reference value UorefBy amplitude reference value UrefWith
Frequency reference frefComposition, by amplitude reference value UrefWith frequency reference frefAccording to formula Uoref=Urefsin2πfrefT enters
Row voltage is synthesized, and obtains the voltage reference value U of every inverter output voltageoref, wherein, t is the time；
Step 3, electricity virtualization is carried out to branch road where every inverter, the electricity virtualization is exactly in traditional inverter
It is improved on the basis of voltage x current double -loop control link, detailed process is as follows：By the every inverter produced in step 2
Reference voltage UorefAs the outer voltage reference value of every contravarianter voltage double current loop modulation link, and with every inverter
The virtual voltage U in exitoIt is compared, the voltage deviation signal U after comparingoref- UoProportional integration control through outer voltage
After device processed, the electric current initial reference value I of current inner loop is obtained* Lref；Virtual voltage proportionality coefficient kvirIt is multiplied by inverter outlet
Virtual voltage UoAfterwards, the virtual circuit voltage at virtual circuit impedance two ends is obtained, virtual circuit voltage is again divided by set in advance
Parallel virtual resistance Rvir, obtain the virtual current I of virtual parallel resistance branchvir, virtual current IvirWith the electric current of current inner loop
Initial reference value I* LrefAfter addition, the revised current reference value I of current inner loop is obtainedLref；
Step 4, by the revised current reference value I of current inner loop in step 3LrefActual inductive current with flowing through filter inductance
ILIt is compared, the current deviation signal I obtained after subtracting each otherLref- ILAfter the proportional controller of current inner loop, obtain corresponding
Modulated signal；
Step 5, the modulated signal in step 4 and carrier signal are compared, obtain the PWM trigger signals of every inverter；
PWM trigger signals drive corresponding device for power switching, make every inverter output target voltage.
2. a kind of inverter parallel droop control method virtualized based on electricity according to claim 1, its feature is existed
In described active-power P and the calculation formula of reactive power Q are：
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<mi>P</mi>
<mo>+</mo>
<mi>j</mi>
<mi>Q</mi>
<mo>=</mo>
<mover>
<mi>U</mi>
<mo>&CenterDot;</mo>
</mover>
<msup>
<mover>
<mi>I</mi>
<mo>&CenterDot;</mo>
</mover>
<mo>*</mo>
</msup>
</mrow>
Wherein,It is inverter output currentConjugation.
Described droop control equation is：
Uref=U0-mPP
fref=f0+mQQ
Wherein, UrefIt is amplitude reference value, frefIt is frequency reference, U0The voltage amplitude of output voltage when being inverter no-load running
Value, f0The frequency of output voltage, m when being inverter no-load runningPIt is the sagging coefficient of active power, mQUnder reactive power
Hang down coefficient.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113013862A (en) * | 2021-03-11 | 2021-06-22 | 国网山西省电力公司经济技术研究院 | Multi-direct-current power distribution network system control method and system for automatic power distribution |
| US11309789B2 (en) | 2019-11-05 | 2022-04-19 | Delta Electronics (Shanghai) Co., Ltd. | Inverter and soft-start method for the same |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20090251933A1 (en) * | 2006-09-04 | 2009-10-08 | Christian Angerer | Method for controlling inverters |
| CN102157956A (en) * | 2011-03-01 | 2011-08-17 | 国网电力科学研究院 | Virtual-impedance-based inverter parallel running method |
| CN102510120A (en) * | 2011-11-23 | 2012-06-20 | 中国科学院电工研究所 | Micro-grid inverter voltage and current double-ring hanging control method based on virtual impedance |
| CN103227581A (en) * | 2013-05-10 | 2013-07-31 | 湖南大学 | Inverter parallel harmonic wave ring current restraining method for controlling harmonic wave droop |
| CN104578182A (en) * | 2015-01-12 | 2015-04-29 | 湖南大学 | Low-delay robust power droop multi-loop control method |
| CN105811421A (en) * | 2016-03-17 | 2016-07-27 | 上海电力学院 | Improved droop control based microgrid auxiliary master-slave control method |
-
2017
- 2017-06-14 CN CN201710448990.9A patent/CN107241028B/en not_active Expired - Fee Related
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20090251933A1 (en) * | 2006-09-04 | 2009-10-08 | Christian Angerer | Method for controlling inverters |
| CN102157956A (en) * | 2011-03-01 | 2011-08-17 | 国网电力科学研究院 | Virtual-impedance-based inverter parallel running method |
| CN102510120A (en) * | 2011-11-23 | 2012-06-20 | 中国科学院电工研究所 | Micro-grid inverter voltage and current double-ring hanging control method based on virtual impedance |
| CN103227581A (en) * | 2013-05-10 | 2013-07-31 | 湖南大学 | Inverter parallel harmonic wave ring current restraining method for controlling harmonic wave droop |
| CN104578182A (en) * | 2015-01-12 | 2015-04-29 | 湖南大学 | Low-delay robust power droop multi-loop control method |
| CN105811421A (en) * | 2016-03-17 | 2016-07-27 | 上海电力学院 | Improved droop control based microgrid auxiliary master-slave control method |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11309789B2 (en) | 2019-11-05 | 2022-04-19 | Delta Electronics (Shanghai) Co., Ltd. | Inverter and soft-start method for the same |
| CN113013862A (en) * | 2021-03-11 | 2021-06-22 | 国网山西省电力公司经济技术研究院 | Multi-direct-current power distribution network system control method and system for automatic power distribution |
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