CN106941257A - A kind of combining inverter compensating control method - Google Patents

A kind of combining inverter compensating control method Download PDF

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Publication number
CN106941257A
CN106941257A CN201610003384.1A CN201610003384A CN106941257A CN 106941257 A CN106941257 A CN 106941257A CN 201610003384 A CN201610003384 A CN 201610003384A CN 106941257 A CN106941257 A CN 106941257A
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voltage
combining inverter
grid
control
current
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王红玲
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Xuchang University
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Xuchang University
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    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00Circuit arrangements for ac mains or ac distribution networks
    • H02J3/12Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load
    • H02J3/16Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load by adjustment of reactive power
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E40/00Technologies for an efficient electrical power generation, transmission or distribution
    • Y02E40/30Reactive power compensation

Abstract

The present invention discloses a kind of combining inverter compensating control method, including:Off-network independent operating is first carried out before combining inverter is grid-connected;Control inversion module output reactive component to carry out transformer combining inverter after pre-excitation, pre-excitation to be connected to the grid;When voltage, which occurs, in combining inverter grid entry point voltage increases above the limitation of predeterminated voltage deviation, grid connected inverter absorption reactive power is controlled, realizes and the dynamic of point of common coupling voltage is adjusted, grid entry point voltage is recovered to voltage deviation scope;When Voltage Drop occurs in grid entry point voltage, control combining inverter sends reactive power, realizes the control generated electricity by way of merging two or more grid systems to combining inverter with grid entry point voltage compensation, grid entry point voltage is recovered to normal voltage range.The combining inverter compensating control method of the present invention, can not only realize the control to grid entry point voltage with dynamic realtime, meet the dynamic response requirement of voltage compensation, and with good compensation precision.

Description

A kind of combining inverter compensating control method
Technical field
The present invention relates to power electronic equipment control technology field, more particularly to a kind of combining inverter compensation Control method.
Background technology
Combining inverter is that, by the device of DC side electric energy feed-in power network in the way of sine-wave current, it is inverse Become a kind of form of device application.The inverter being incorporated into the power networks is widely used, such as alternating current electronic load, can be again The occasion that raw energy large-scale grid connection generates electricity is required for grid-connected inverters to run, by the electric energy feedback in system extremely In power network.However, being polluted in order to avoid the grid-connected current of poor quality to power network, the ripple of grid-connected current Form quality amount has strict requirements, and electric current is the sine wave with voltage with same frequency and reversed-phase, and meets International Power committee member Can standard.It is as follows to the current specification of combining inverter feed-in power network in the world:Waveform is sine, total harmonic wave Aberration rate THD is less than 5%, and each harmonic is less than 3%.
It is to determine to select corresponding filter construction and suitable grid-connected control method according to different workplaces The key of the current quality of combining inverter feed-in power network.The performance of combining inverter, which is directly connected to, is incorporated to electricity The quality of electric energy in net, and distributed generation system energy conversion efficiency.The effect of combining inverter is The energy of distributed generation unit and the DC form of tank voltage is converted to the energy of form of communication, so that It is attached with external electrical network and energy exchange.Now, the control targe of inverter is usually output wattful power Rate and output reactive power.
The control mode of combining inverter is divided into two kinds of voltage control and current control.Voltage control is equivalent to general Inverter is equivalent to a voltage source, its output voltage phase, frequency is fully equivalent to power network by control Voltage, the amplitude of amplitude tracking line voltage, essence is equivalent to by two voltage source parallel connections.But due to civil power Voltage is likely to produce distortion or larger harmonic wave during operation, and inverter can be caused to export can not be accurate Line voltage is tracked, makes the increase of control difficulty.In addition, this by controlling inverter output voltage come indirectly The control mode of control grid-connected current can not make grid-connected current reach preferable quality.
There are following several control modes in the prior art:
1) Direct Current Control mode is broadly divided into Hysteresis control and triangular wave control.
2) Hysteresis control uses hysteresis comparator, and the deviation of reference current and actual grid-connected current is defeated as its Enter, hysteresis comparator produces pwm signal, by controlling the break-make of inverter circuit switching power devices to control Grid-connected current processed.If setting hysteresis comparator ring width as 2h, it is possible to by grid-connected current control default Within the scope of, make grid-connected current be serrated ground track reference electric current.For this control method, scope Set larger to systematic influence:When ring width is wider, the frequency reduction of switch motion, but error increase, harmonic wave It is very big;When ring width is narrower, error reduces, harmonic wave reduction, but switch motion frequency is too high, and switching loss increases Greatly.For the disadvantages mentioned above of hysteresis comparator, a kind of solution is to use synchro switch method, i.e. timing control The instantaneous value manner of comparison of system.
Hysteresis comparator is more due to the contradiction before its switching frequency and precision, and higher hamonic wave, and electromagnetism is done Disturb larger, act in actual applications limited.The wide control mode of application is triangular wave controlling party at present Formula.
3) triangular wave control mode can use the control of the different complete paired systems of controller, and such as PI is controlled, Repetitive controller, track with zero error etc..The waveform drawn after the regulation of current error via controller is carried out with triangular wave Compare, generate SPWM ripples, control the break-make of device for power switching.Triangular wave control mode power switch Frequency is equal to carrier frequency, and noise is low, it is easy to design wave filter, various ways can be taken to be controlled, and drops Low error.
In general, the inverter constituted using power electronic devices can produce substantial amounts of current harmonics, therefore, The wave filter that passive device is constituted is used to filter these harmonic waves.The wave filter that combining inverter is used is usual There are two kinds:Inductance (LC) wave filter and inductor-capacitor-inductance (LCL) wave filter.It is identical in inductance value, In the case that cost is suitable, LCL filter has more preferable filter effect.However, LCL filter conduct One third-order system, easily produces resonance, causes the unstable of system.
LC wave filters are also referred to as passive filter, are traditional harmonic compensation devices.Why is LC wave filters Referred to as passive filter, is exactly that the device need not be additionally provided power supply as its name suggests.LC wave filters are general It is by filter condenser, reactor and resistor is appropriately combined forms, it is in parallel with harmonic source, make except filtering is played With outer, the need for also taking into account reactive-load compensation;LC wave filters are divided into LC low pass filters, LC according to function Bandpass filter, high-pass filter, LC all-pass filters, LC bandstop filters;It is divided into list again by tuning Tuning filtering device, double-tuned filter and three-tuned filter etc. are several.
LC wave filters design cycle mainly considers that its resonant frequency and capacitor are pressure-resistant, the resistance to stream of reactor.In electricity In sub-line road, inductance coil is to exchange current limiting effect, by the induction reactance formula X of inductanceL=2 π fL are understood, electric Sense L is bigger, and frequency f is higher, and induction reactance is bigger.Therefore inductance coil has logical low frequency, hinders the effect of high frequency, this It is that LC filter circuit example inductance is exactly below the filtering principle of inductance in the most common effect of circuit to be exactly Together with electric capacity, LC filter circuits are constituted.Ability of the electric capacity with " resistance direct current, lead to exchange ", and inductance Then there is the function of " logical direct current, resistance exchange, leads to low frequency, hinders high frequency ".
If the direct current with many interference signals is passed through LC filter circuits, then, AC influence signal Major part will be prevented absorption from becoming magnetic strength and heat energy by inductance, and remaining major part is by capacitive bypass to ground, and this is just The effect of interference signal can be suppressed, purer DC current is just obtained in output end.The original of filter circuit Reason is really that the combination of L, c element fundamental characteristics is utilized.Because the capacitive reactance x of capacitorc=2nfc again 1 can be with Signal frequency is raised and diminished, and the induction reactance x of inductorl=2f can be raised and increased with signal frequency, if handle Electric capacity, inductance carry out series, parallel or series-parallel connection application, and the impedance that they are combined also can be with signal frequency difference This shows that very little or very big reactance can be presented to certain frequency signal in different filter circuits to generation very people's change mouth, Allow the frequency signal to pass through with enable or hinder it to pass through, so as to play certain frequency signal of selection and filter Except the effect of certain frequency signal.
Generally, suppressing resonance has two ways:One kind is passive damped method, and another is active damping method. So-called passive damped method, is usually to increase resistance in inverter circuit directly to increase the resistance of LCL filter Buddhist nun, but either series connection or parallel resistance, can increase the excess loss of system.So-called active damping Method, is usually taken the control to contravarianter voltage electric current to realize the purpose of suppression resonance, conventional high-order pole The bicyclic PI control strategies of point configuration, weighted current average back PI control strategies, and grid-connected current, Three ring PI control strategies of capacitance voltage and inductive current etc..
But, in above method, although PI controllers can make grid-connected inverter system have preferable property Can, when system is larger by external disturbance, its dynamic property also needs to further improve grid-connected right to meet The requirement of current waveform and total harmonic distortion factor.It can be carried by the way of other controllers are combined with PI controls High system robustness.
But combining inverter is a complicated nonlinear system, accurate Mathematical Modeling is set up to it often non- It is often difficult.And in the design process of controller, it is often necessary to it is designed according to the Mathematical Modeling of system.
It can only obtain approximate model at present for combining inverter and Accurate Model can not be accomplished.If simultaneously Having seen of net inverter introduces fuzzy control in that system, then can partly be compensated the characteristics of fuzzy control and be The inexactness of system model.Compared with traditional control method, fuzzy control using control object as "black box", it Independent of the Mathematical Modeling of system, and it is to rely on the fuzzy rule being simply converted into by operating experience, statement Then, it is one kind of Based Intelligent Control.
Often robustness height, dynamic property are good for the system of addition fuzzy control.By fuzzy control and other controls Method is combined, and is to compare multiplex combining inverter control mode at present, development potentiality is larger.But pass The control parameter of system fuzzy control method is fixed, it is impossible to carry out on-line tuning with the working condition of system. The ratio and integral coefficient of PI controllers are constant, and this causes in system architecture change or parameter fluctuation (such as External electrical network structure is broken down or inner side DC bus-bar voltage is acutely raised) when, inverter without The quick accurate tracing control instruction of method, it is impossible to the active and reactive power of regulation input and output in time.Reduction The stability and antijamming capability of net inverter.
The content of the invention
The present invention is based on the one or more problems of the above there is provided a kind of combining inverter compensating control method, It is low to solve combining inverter networking current quality present in prior art, it is impossible to realize voltage dynamically benefit The problem of repaying.
Wherein, the combining inverter compensating control method, including:
Off-network independent operating is first carried out before combining inverter is grid-connected;
Inversion module output reactive component is controlled, it is described grid-connected after pre-excitation, pre-excitation to be carried out to transformer Inverter is connected to the grid;
When, which there is voltage, in the combining inverter grid entry point voltage increases above the limitation of predeterminated voltage deviation, The grid connected inverter absorption reactive power is controlled, realizes and the dynamic of point of common coupling voltage is adjusted, make simultaneously Site voltage recovers to voltage deviation scope;
When Voltage Drop occurs in the grid entry point voltage, the combining inverter is controlled to send reactive power, The control for generating electricity by way of merging two or more grid systems the combining inverter with grid entry point voltage compensation is realized, makes the grid entry point voltage Recover to normal voltage range.
Further, the control inversion module output reactive component, is included with carrying out pre-excitation to transformer:
Using the output quantity of excitation instruction module output as the reference signal of q shaft current adjusters, inverter is controlled Export reactive component and pre-excitation is carried out to inverter;The excitation instruction module includes at least one input quantity, The output quantity of the excitation instruction module is by a monotonically increasing function with the upper limit by the input quantity Computing is obtained.
Further, the input quantity of the excitation instruction module is the no-load current of the combining inverter.
Further, the input quantity of the excitation instruction module is the no-load current of the combining inverter, with And the mould of line voltage vector.
Further, the pre-excitation completes to refer to:The exciting current of the combining inverter reaches that it is unloaded Current value;
The DC bus-bar voltage that direct current signal detection module is detected during whole off-network independent operating is tieed up all the time Hold on minimum operation DC bus-bar voltage point and kept for one time set in advance.
Further, the dynamic adjustment to point of common coupling voltage includes:
The three-phase instantaneous voltage of combining inverter grid entry point is gathered in real time, by voltage transient amplitude and Voltage Reference Amplitude, which is compared, obtains error magnitude;
The error magnitude is obtained into voltage adjustment reactive-load compensation electric current after the regulation of voltage compensation pi regulator, After voltage adjustment reactive-load compensation electric current is superimposed with quadrature network reference value, then inverter is controlled.
Further, the control generated electricity by way of merging two or more grid systems to combining inverter with grid entry point voltage compensation includes:
Grid entry point three-phase instantaneous voltage is obtained into voltage under two-phase rotating coordinate system by coordinate transform;
Calculated by amplitude and obtain grid entry point voltage magnitude;
Reactive voltage component is compared with reference value, error is obtained simultaneously after pi regulator control through integrator The real-time phase of site voltage;
Combining inverter is completed according to the voltage magnitude and the voltage-phase to generate electricity by way of merging two or more grid systems and grid entry point voltage Compensate control function.
Further, the voltage magnitude is calculated as:Wherein, Ud、UqIt is instantaneous for three-phase Value of the voltage under two-phase rotating coordinate system.
Further, the grid entry point voltage compensation is realized by equation below:
E (k)=Uref-Uamp
I (k)=kvp[e(k)-e(k-1)]
ei(k)=Id-Id(k)
Id(k)=Id(k-1)+kip[ei(k)-ei(k-1)]+ke(k)
eIq(k)=Iq-Iq(k)
Iq(k)=Iq(k-1)+kip[ei(k)-ei(k-1)]+ke(k)
Wherein:K represents kth secondary control, and e (k) represents voltage deviation, UrefRepresent the Voltage Reference width of setting Value, UampGrid entry point voltage monitoring amplitude is represented, I (k) represents voltage control unit reactive-load compensation electric current, Id(k) Represent reactive current component, Iq(k) active current, k are representedipRepresent voltage controller scale parameter, kvp Represent voltage controller integral parameter, IdRepresent reactive current total amount, IqRepresent watt current total amount.
Further, power network specification pair is increased above when voltage occurs in the grid entry point voltage of the combining inverter During the limitation of voltage deviation, output first voltage compensation electric current, the idle ginseng given with the combining inverter Examine electric current superposition and obtain new idle reference current, control the grid connected inverter absorption reactive current, make simultaneously Site voltage recovers to voltage deviation scope;
When Voltage Drop occurs in the grid entry point voltage, output second voltage compensation electric current is and described grid-connected The given idle reference current superposition of inverter, controls the combining inverter to send reactive current, makes described Grid entry point voltage recovers to normal voltage range.
The combining inverter compensating control method that the present invention is provided, compared with prior art, on the one hand need not Extra voltage compensation unit is installed, directly voltage compensated in itself using combining inverter;The opposing party Face, says in terms of control strategy, and traditional voltage compensation strategy is all steady state voltage compensation policy, compensation speed Degree is slow, it is impossible to meet the requirement of voltage compensation dynamic response, and voltage compensation precision is also than relatively low, The compensation capacity provided is needed than larger.The present invention can not only be realized to grid entry point voltage with dynamic realtime Control, meets the dynamic response requirement of voltage compensation, and with good compensation precision, required benefit Repay capacity also much smaller compared with Traditional control strategy.
Brief description of the drawings
Fig. 1 is a kind of combining inverter compensating control method flow chart of the embodiment of the present invention one;
Fig. 2 is the combining inverter structure chart of the embodiment of the present invention two;
Fig. 3 is a kind of control principle drawing of combining inverter compensating control method of the embodiment of the present invention two.
Embodiment
The present invention is described in detail with reference to the accompanying drawings and examples.If it should be noted that do not rushed Prominent, each feature in the embodiment of the present invention and embodiment can be combined with each other, the protection in the present invention Within the scope of.
Embodiment one
The embodiment of the present invention one provides a kind of combining inverter compensating control method, as shown in figure 1, this method Including:
101st, off-network independent operating is first carried out before combining inverter is grid-connected;
102nd, control inversion module output reactive component carries out parallel network reverse after pre-excitation, pre-excitation to transformer Device is connected to the grid;
The step is specifically included:Using the output quantity of excitation instruction module output as the reference of q shaft current adjusters Signal, control inverter output reactive component carries out pre-excitation to inverter;The excitation instruction module includes At least one input quantity, the output quantity of the excitation instruction module is that input quantity is had into the upper limit by one Monotonically increasing function computing is obtained.
Wherein, the input quantity of the excitation instruction module is the no-load current of the combining inverter.
The input quantity of the excitation instruction module is the no-load current of the combining inverter, and line voltage The mould of vector.
The pre-excitation completes to refer to:The exciting current of the combining inverter reaches its no-load current value;
The DC bus-bar voltage that direct current signal detection module is detected during whole off-network independent operating is tieed up all the time Hold on minimum operation DC bus-bar voltage point and kept for one time set in advance.
103rd, when voltage, which occurs, in combining inverter grid entry point voltage increases above the limitation of predeterminated voltage deviation, Grid connected inverter absorption reactive power is controlled, realizes and the dynamic of point of common coupling voltage is adjusted, make grid entry point Voltage recovers to voltage deviation scope;
Wherein, the dynamic adjustment to point of common coupling voltage includes:
The three-phase instantaneous voltage of combining inverter grid entry point is gathered in real time, by voltage transient amplitude and Voltage Reference Amplitude, which is compared, obtains error magnitude;
The error magnitude is obtained into voltage adjustment reactive-load compensation electric current after the regulation of voltage compensation pi regulator, After voltage adjustment reactive-load compensation electric current is superimposed with quadrature network reference value, then inverter is controlled.
Specifically, increasing above power network specification to voltage deviation when voltage occurs in combining inverter grid entry point voltage Limitation when, output first voltage compensation electric current, with combining inverter give idle reference current be superimposed To new idle reference current, grid connected inverter absorption reactive current is controlled, grid entry point voltage is recovered to electricity Press within deviation range;
104th, when Voltage Drop occurs in grid entry point voltage, control combining inverter sends reactive power, realizes The control generated electricity by way of merging two or more grid systems to combining inverter with grid entry point voltage compensation, makes grid entry point voltage recover to normal electricity Press scope.
Wherein, the control generated electricity by way of merging two or more grid systems to combining inverter with grid entry point voltage compensation includes:
Grid entry point three-phase instantaneous voltage is obtained into voltage under two-phase rotating coordinate system by coordinate transform;
Calculated by amplitude and obtain grid entry point voltage magnitude;
Reactive voltage component is compared with reference value, error is obtained simultaneously after pi regulator control through integrator The real-time phase of site voltage;
Combining inverter is completed according to the voltage magnitude and the voltage-phase to generate electricity by way of merging two or more grid systems and grid entry point voltage Compensate control function.
Specifically, the voltage magnitude is calculated as:Wherein, Ud、UqIt is instantaneously electric for three-phase It is pressed in the value under two-phase rotating coordinate system.
The grid entry point voltage compensation is realized by equation below:
E (k)=Uref-Uamp
I (k)=kvp[e(k)-e(k-1)]
ei(k)=Id-Id(k)
Id(k)=Id(k-1)+kip[ei(k)-ei(k-1)]+ke(k)
eIq(k)=Iq-Iq(k)
Iq(k)=Iq(k-1)+kip[ei(k)-ei(k-1)]+ke(k)
Wherein:K represents kth secondary control, and e (k) represents voltage deviation, UrefRepresent the Voltage Reference width of setting Value, UampGrid entry point voltage monitoring amplitude is represented, I (k) represents voltage control unit reactive-load compensation electric current, Id(k) Represent reactive current component, Iq(k) active current, k are representedipRepresent voltage controller scale parameter, kvp Represent voltage controller integral parameter, IdRepresent reactive current total amount, IqRepresent watt current total amount.
Specifically, when Voltage Drop occurs in grid entry point voltage, output second voltage compensation electric current is and grid-connected The given idle reference current superposition of inverter, control combining inverter sends reactive current, makes grid entry point electricity Pressure is recovered to normal voltage range.
The combining inverter compensating control method that the present invention is provided, compared with prior art, on the one hand need not Extra voltage compensation unit is installed, directly voltage compensated in itself using combining inverter;The opposing party Face, says in terms of control strategy, and traditional voltage compensation strategy is all steady state voltage compensation policy, compensation speed Degree is slow, it is impossible to meet the requirement of voltage compensation dynamic response, and voltage compensation precision is also than relatively low, The compensation capacity provided is needed than larger.The present invention can not only be realized to grid entry point voltage with dynamic realtime Control, meets the dynamic response requirement of voltage compensation, and with good compensation precision, required benefit Repay capacity also much smaller compared with Traditional control strategy.
Embodiment two
The embodiment of the present invention one provides a kind of combining inverter compensating control method, applied to as shown in Figure 2 In photovoltaic combining inverter, the inverter includes:Direct current signal detection module, for detecting the straight of input side Flow voltage/current;Inversion module, for the direct current of input to be converted into alternating current;Transformer, for inciting somebody to action The ac output end of inverter module is isolated with power network, A.C. contactor, for switching photovoltaic combining inverter Off-network and net state;Alternating current signal detection module, the output current for detecting photovoltaic combining inverter And line voltage;Circuit is controlled, is controlled for the operation to photovoltaic combining inverter.
Fig. 3 is a kind of control principle drawing of combining inverter compensating control method of inventive embodiments two.Wherein, Voltage, the collection of current sampling unit circuit mainly complete combining inverter grid entry point three-phase voltage signal and grid-connected The collection of inverter output current signal, and send described voltage, current signal to voltage-phase and width Value detection computing unit, voltage deviation computer voltage compensation unit, grid-connected current control unit.
Voltage-phase and the detection of amplitude detection computing unit and calculating combining inverter grid entry point voltage-phase and electricity Pressure amplitude value.First by the way that grid entry point three-phase voltage is passed through into coordinate transform, then obtained by amplitude computing formula Voltage magnitude.Voltage phase information and amplitude information are sent into voltage deviation to calculate and voltage compensation list Member, grid-connected current control unit.
Voltage deviation computer voltage compensation unit mainly receives to calculate from voltage-phase and amplitude detection The voltage magnitude information of unit, and voltage magnitude is compared with voltage setting reference value, mended by voltage Controller is repaid, the rise of grid entry point voltage or Voltage Drop are realized and compensated.When grid entry point voltage is raised, and Net inverter absorbs certain reactive power by voltage compensation unit;When grid entry point Voltage Drop, Combining inverter sends certain reactive power by voltage compensation unit.
Grid-connected current control unit on the one hand normally realize by the main combining inverter grid-connected current control unit that completes The major function generated electricity by way of merging two or more grid systems, on the other hand receives to calculate from voltage deviation and voltage compensation unit Grid entry point voltage compensation circuit.When grid entry point voltage is raised, combining inverter passes through grid entry point voltage deviation Calculate and voltage compensation unit absorbs certain reactive power, it is grid-connected inverse when grid entry point Voltage Drop Become device and certain reactive power is sent by voltage compensation unit, realize grid entry point voltage compensation Miscellaneous function.Meanwhile, grid-connected current control unit will also produce three-phase bridge switching tube driving control signal, complete Into the normal operation of electric current.
In above-mentioned transformer pre-excitation control process, the output current of control inversion module gradually increases from 0, The output voltage of photovoltaic combining inverter also gradually increases with the increase of corresponding exciting current from 0, and phase Pre- electric network voltage phase is always consistent, progressively carries out pre-excitation to transformer, when inversion module exports electricity When stream is that the exciting current of transformer increases to the amplitudes such as no-load transformer electric current, inverter output voltage and electricity Net also reaches unanimously, the constant output voltage signal output of inverter is now kept, until only in whole off-network The DC bus-bar voltage that direct current signal detection module is detected in vertical running remains at minimum operation direct current On busbar voltage point and keep a period of time, then control A.C. contactor adhesive be connected to the grid, if directly Flow side energy it is not enough when, it may appear that DC bus-bar voltage falls less than minimum operation DC bus-bar voltage point, then Stop off-network independent operating, and detect inverter startup again, repeat above-mentioned independent operating process.
When wherein described electric network voltage phase and inverter output voltage and electric current Park conversion, inverse transformation The phase angle used has a variety of methods to obtain in the prior art, and the preferable method of two of which is:One is electricity Net voltage carries out Clark conversion, by the arctan function to voltage under static rotational coordinates, and by setting The filter filtering counted tries to achieve power network vector voltage phase angle.Two be to obtain phase angle using three-phase phase-locked loop.
Embodiments of the present invention are the foregoing is only, are not intended to limit the scope of the invention, it is every to utilize Equivalent structure or equivalent flow conversion that description of the invention and accompanying drawing content are made, or directly or indirectly use In other related technical fields, it is included within the scope of the present invention.

Claims (10)

1. a kind of combining inverter compensating control method, it is characterised in that including:
Off-network independent operating is first carried out before combining inverter is grid-connected;
Inversion module output reactive component is controlled, it is described grid-connected after pre-excitation, pre-excitation to be carried out to transformer Inverter is connected to the grid;
When, which there is voltage, in the combining inverter grid entry point voltage increases above the limitation of predeterminated voltage deviation, The grid connected inverter absorption reactive power is controlled, realizes and the dynamic of point of common coupling voltage is adjusted, make simultaneously Site voltage recovers to voltage deviation scope;
When Voltage Drop occurs in the grid entry point voltage, the combining inverter is controlled to send reactive power, The control for generating electricity by way of merging two or more grid systems the combining inverter with grid entry point voltage compensation is realized, makes the grid entry point voltage Recover to normal voltage range.
2. combining inverter compensating control method as claimed in claim 1, it is characterised in that:
The control inversion module output reactive component, is included with carrying out pre-excitation to transformer:
Using the output quantity of excitation instruction module output as the reference signal of q shaft current adjusters, inverter is controlled Export reactive component and pre-excitation is carried out to inverter;The excitation instruction module includes at least one input quantity, The output quantity of the excitation instruction module is by a monotonically increasing function with the upper limit by the input quantity Computing is obtained.
3. combining inverter compensating control method as claimed in claim 2, it is characterised in that:
The input quantity of the excitation instruction module is the no-load current of the combining inverter.
4. combining inverter compensating control method as claimed in claim 2, it is characterised in that:
The input quantity of the excitation instruction module is the no-load current of the combining inverter, and line voltage The mould of vector.
5. combining inverter compensating control method as claimed in claim 1, it is characterised in that:It is described pre- to encourage Magnetic completes to refer to:The exciting current of the combining inverter reaches its no-load current value;
The DC bus-bar voltage that direct current signal detection module is detected during whole off-network independent operating is tieed up all the time Hold on minimum operation DC bus-bar voltage point and kept for one time set in advance.
6. combining inverter compensating control method as claimed in claim 1, it is characterised in that:It is described to public affairs The dynamic adjustment of Coupling point voltage includes altogether:
The three-phase instantaneous voltage of combining inverter grid entry point is gathered in real time, by voltage transient amplitude and Voltage Reference Amplitude, which is compared, obtains error magnitude;
The error magnitude is obtained into voltage adjustment reactive-load compensation electric current after the regulation of voltage compensation pi regulator, After voltage adjustment reactive-load compensation electric current is superimposed with quadrature network reference value, then inverter is controlled.
7. combining inverter compensating control method as claimed in claim 6, it is characterised in that:Described pair simultaneously The control that net grid-connected inverters generate electricity with grid entry point voltage compensation includes:
Grid entry point three-phase instantaneous voltage is obtained into voltage under two-phase rotating coordinate system by coordinate transform;
Calculated by amplitude and obtain grid entry point voltage magnitude;
Reactive voltage component is compared with reference value, error is obtained simultaneously after pi regulator control through integrator The real-time phase of site voltage;
Combining inverter is completed according to the voltage magnitude and the voltage-phase to generate electricity by way of merging two or more grid systems and grid entry point voltage Compensate control function.
8. combining inverter compensating control method as claimed in claim 7, it is characterised in that:
The voltage magnitude is calculated as:Wherein, Ud、UqIt is three-phase instantaneous voltage in two-phase Value under rotating coordinate system.
9. combining inverter compensating control method as claimed in claim 7, it is characterised in that:It is described grid-connected Point voltage compensation is realized by equation below:
E (k)=Uref-Uamp
I (k)=kvp[e(k)-e(k-1)]
ei(k)=Id-Id(k)
Id(k)=Id(k-1)+kip[ei(k)-ei(k-1)]+ke(k)
eIq(k)=Iq-Iq(k)
Iq(k)=Iq(k-1)+kip[ei(k)-ei(k-1)]+ke(k)
Wherein:K represents kth secondary control, and e (k) represents voltage deviation, UrefRepresent the Voltage Reference width of setting Value, UampGrid entry point voltage monitoring amplitude is represented, I (k) represents voltage control unit reactive-load compensation electric current, Id(k) Represent reactive current component, Iq(k) active current, k are representedipRepresent voltage controller scale parameter, kvp Represent voltage controller integral parameter, IdRepresent reactive current total amount, IqRepresent watt current total amount.
10. combining inverter compensating control method as claimed in claim 1, it is characterised in that:
Power network specification is increased above to voltage deviation when voltage occurs in the grid entry point voltage of the combining inverter During limitation, output first voltage compensation electric current, the idle reference current given with the combining inverter is superimposed New idle reference current is obtained, the grid connected inverter absorption reactive current is controlled, makes grid entry point voltage extensive Answer to voltage deviation scope;
When there is Voltage Drop in the grid entry point voltage, output second voltage compensation electric current, with the parallel network reverse The given idle reference current superposition of device, controls the combining inverter to send reactive current, makes described grid-connected Point voltage recovers to normal voltage range.
CN201610003384.1A 2016-01-05 2016-01-05 A kind of combining inverter compensating control method Pending CN106941257A (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107482674A (en) * 2017-07-25 2017-12-15 中国科学院电工研究所 Grid entry point voltage for distributed generation system rises suppressing method
CN108183501A (en) * 2017-12-15 2018-06-19 北京交通大学 Consider the photovoltaic system points of common connection voltage control method of three-phase imbalance
CN108599132A (en) * 2018-05-24 2018-09-28 安徽工业大学 The method and system of direct-current micro-grid segmentation droop control under the conditions of improvement continuous duty

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107482674A (en) * 2017-07-25 2017-12-15 中国科学院电工研究所 Grid entry point voltage for distributed generation system rises suppressing method
CN107482674B (en) * 2017-07-25 2020-06-05 中国科学院电工研究所 Grid-connected point voltage rise suppression method for distributed power generation system
CN108183501A (en) * 2017-12-15 2018-06-19 北京交通大学 Consider the photovoltaic system points of common connection voltage control method of three-phase imbalance
CN108183501B (en) * 2017-12-15 2020-03-06 北京交通大学 Photovoltaic system common connection point voltage control method considering three-phase imbalance
CN108599132A (en) * 2018-05-24 2018-09-28 安徽工业大学 The method and system of direct-current micro-grid segmentation droop control under the conditions of improvement continuous duty
CN108599132B (en) * 2018-05-24 2020-03-24 安徽工业大学 Method and system for improving direct-current micro-grid sectional droop control under continuous load condition

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