Summary of the invention
In view of this, the invention provides a kind of control method of grid-connected inverter and system, solve existingTechnology reduces the technical problem of inversion efficiency because inversion busbar voltage is too high.
To achieve these goals, this application provides techniques below scheme:
A kind of control method of grid-connected inverter, described method includes:
The actual bus voltage of monitoring inverter bus；
Calculate the first difference between described actual bus voltage and target bus voltage, described target busVoltage is the minimum voltage meeting described inverter success inversion；
Judge that whether the absolute value of described first difference is more than the first voltage threshold；
If it is, utilize the target current value of inductance element in inverter described in described first mathematic interpolation；
According to the current flow of inductance element in the described target current value described inverter of regulation until monitoringActual bus voltage and described target bus voltage between the absolute value of difference be not more than described first electricityPressure threshold value.
Preferably, the current flow of the inductance element in the described inverter of described regulation includes:
When described actual bus voltage is more than described target bus voltage, increase inductance in described inverterThe current flow of element；
When described actual bus voltage is less than described target bus voltage, reduce inductance in described inverterThe current flow of element.
Preferably, before the actual bus voltage of monitoring inverter bus, described method also includes:
Monitor the actual PV voltage of the PV plate output corresponding with described inverter；
Calculate the second difference between described actual PV voltage and default target bus voltage.
Preferably, when judging that described second difference is more than zero and more than described first voltage threshold, andWhen described actual bus voltage reaches to preset expectation PV voltage, described method also includes:
Described PV plate is carried out MPPT scanning, determines the actual expectation PV voltage of described PV plate；
Calculate the currently practical PV voltage of the described PV plate detected and described actual expectation PV voltage3rd difference；
Judge that whether the absolute value of described 3rd difference is more than the second voltage threshold；
If it is, utilize described 3rd difference to adjust the DC/DC being connected with described PV plate outfanThe current flow of inductance element in changer, until the actual PV voltage detected and described actual expectationThe absolute value of the difference of PV voltage is not more than described second voltage threshold.
Preferably, when judging described second difference, less than zero and absolute value is more than described first voltage threshold,And make the absolute value of described first difference be not more than institute by described actual PV boost in voltage is processedWhen stating the first voltage threshold, described method also includes:
Described PV plate is carried out MPPT scanning, determines the actual expectation PV voltage of described PV plate；
Calculate the currently practical PV voltage of the described PV plate detected and described actual expectation PV voltage4th difference；
Judge that whether the absolute value of described 4th difference is more than tertiary voltage threshold value；
If it is, utilize described 4th difference to adjust the DC/DC being connected with described PV plate outfanThe current flow of inductance element in changer, until the actual PV voltage detected and described actual expectationThe absolute value of the difference of PV voltage is not more than described tertiary voltage threshold value.
Preferably, described method also includes:
Detection bearing power and the grid-connected power of described inverter；
When judging described grid-connected power more than described bearing power, by described actual bus voltage blood pressure loweringTo the nominal charging voltage of energy-storage battery, it is delivered to energy-storage battery；
When judging described grid-connected power less than described bearing power, the voltage liter that energy-storage battery is exportedIt is depressed into described target bus voltage, is delivered to described inverter.
Preferably, described energy-storage battery is being charged or in described energy-storage battery discharge process, describedMethod also includes:
Monitor the physical holding of the stock capacity of described energy-storage battery；
When the maximum storage capacity that capacity reaches described energy-storage battery is deposited in described actual energy storage, to described storageCharging can be stopped by battery；
When described physical holding of the stock capacity reaches the minimum storage volume of described energy-storage battery, control described storageElectric discharge can be stopped by battery.
A kind of combining inverter control system, described system includes PV plate and is connected in parallel on inverter input terminalStorage capacitor, described system also includes:
Input is connected with PV plate outfan, and outfan is connected with described inverter input terminal, has boostingAnd buck functionality, and described PV plate is carried out MPPT scanning, determine the actual expectation of described PV plateOneth DC/DC changer of PV voltage；
It is connected with described storage capacitor two ends, the first monitoring of the actual bus voltage of monitoring inverter busDevice；
It is connected with described first monitoring device and described inverter, receives the institute of this first monitoring device outputState actual bus voltage, and calculate the first difference between described actual bus voltage and target bus voltage,When the absolute value judging described first difference is more than the first voltage threshold, utilize this first mathematic interpolationThe target current value of inductance element in described inverter, and regulate described inversion according to described target current valueThe current flow of inductance element in device, until the actual bus voltage monitored and described target bus voltageBetween absolute difference be not more than the first control device of described first voltage threshold；
Wherein, described target bus voltage is the minimum voltage meeting described inverter success inversion.
Preferably, described system also includes:
It is connected with described PV plate outfan, monitors the second prison of the actual PV voltage of described PV plate outputSurvey device；
It is connected with described second monitoring device and a described DC/DC changer, calculates the second monitoring deviceThe actual PV voltage sent and actual the 3rd difference expecting PV voltage, when judging described 3rd differenceAbsolute value more than the second voltage threshold time, utilize described 3rd difference adjust described oneth DC/DC conversionThe current flow of inductance element in device, until the actual PV voltage monitored and described actual expectation PV electricityThe absolute value of the difference of pressure is not more than the second control device of described second voltage threshold.
Preferably, described system also includes:
One end is connected with described inverter input terminal, has the 2nd DC/DC conversion of boosting and buck functionalityDevice；
The energy-storage battery being connected with the other end of described 2nd DC/DC changer.
As can be seen here, compared with prior art, this application provides a kind of control method of grid-connected inverter andSystem, by monitoring in real time the actual bus voltage of inverter bus, when judging that this reality is femaleWhen the absolute value of the first difference of line voltage and target bus voltage is more than the first voltage threshold, utilize thisOne mathematic interpolation goes out the target current value of inductance element in inverter, and wherein, this target bus voltage is fullThe minimum voltage of the described inverter success inversion of foot, afterwards, the present invention is inverse to this according to this target current valueBecome the regulation of the current flow of inductance element in device, thus reduce between actual bus voltage and target busThe first difference, until the absolute value of this first difference is not more than the first voltage threshold, it is to avoid because of inversionThe overtension of bus (i.e. more than the minimal reverse variable bus voltage needed for inversion) and make to be connected in parallel on inversionCapacitance damage on bus, solves in prior art simultaneously and reduces inversion because inversion busbar voltage is too highThe problem of conversion efficiency.
Detailed description of the invention
Below in conjunction with the accompanying drawing in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is carried outClearly and completely describe, it is clear that described embodiment is only a part of embodiment of the present invention, andIt is not all, of embodiment.Based on the embodiment in the present invention, those of ordinary skill in the art are not doingGo out the every other embodiment obtained under creative work premise, broadly fall into the scope of protection of the invention.
This application provides a kind of control method of grid-connected inverter and system, by the reality to inverter busBorder busbar voltage is monitored in real time, when judging the first of this actual bus voltage and target bus voltageWhen the absolute value of difference is more than the first voltage threshold, utilize inductance element in this first mathematic interpolation inverterTarget current value, wherein, this target bus voltage is the minimum electricity meeting described inverter success inversionPressure, afterwards, the present invention regulates the current flow of inductance element in this inverter according to this target current value,Thus reduce the first difference between actual bus voltage and target bus, until this first difference is absoluteValue is not more than the first voltage threshold, it is to avoid make to be connected in parallel on inversion because of the overtension of inversion bus femaleCapacitance damage on line, solves in prior art simultaneously and reduces inversion turn because inversion busbar voltage is too highThe problem changing efficiency.
As it is shown in figure 1, be the schematic flow sheet of the present invention a kind of control method of grid-connected inverter embodiment, shouldThe concrete steps of method may include that
Step S101: the actual bus voltage of monitoring inverter bus.
In the present embodiment, the control structure block diagram of inverter as shown in Figure 2, PV (Photo Voltaic,Light cell) plate outfan accesses has boosting and a DC/DC changer of buck functionality, and this is first years oldDC/DC converter output terminal connects the inversion bus i.e. input of single-phase inverter, wherein, inversion busA upper electric capacity C in parallel is bus capacitor.
As a example by single-phase 230V electrical network, the minimum inversion busbar voltage meeting reliable inversion is about230*1.414+25=350V, wherein, 25V is allowance, control structure block diagram based on above-mentioned inverter,In actual applications, it is assumed that the output voltage range of this PV board component is 300V～800V, when PV plate is openedWhen beginning work output PV voltage is low pressure (i.e. PV voltage be less than minimum inversion busbar voltage), will be by theOne DC/DC changer carries out boosting process to PV voltage, it will usually more than 350V (i.e. inversion busVoltage is more than 350V) after, start inverter side voltage-stabilizing system and the voltage stabilizing of inversion busbar voltage is processed, simultaneouslyControl a DC/DC changer and PV plate is carried out MPPT scanning, in order to PV side voltage-stabilizing system is to thisPV voltage carries out voltage stabilizing process.
In like manner, when PV plate start working output PV voltage be high pressure (i.e. PV voltage be more than minimum inversionBusbar voltage) time, a DC/DC changer does not works, and PV plate is directly inversion by bypass modeBussed supply, then the actual bus voltage of inverter side is more than target equal to PV voltage, i.e. actual bus voltageBusbar voltage, processes starting inverter side voltage-stabilizing system the voltage stabilizing of inversion busbar voltage, controls the simultaneouslyOne DC/DC changer carries out MPPT scanning to PV plate, in order to PV side voltage-stabilizing system is to this PV electricityPressure carries out voltage stabilizing process.
Thus, in present example, in order to avoid bus capacitor C voltage is too high and damage, or,Inversion busbar voltage cannot meet the minimum voltage needed for inversion, it will carries out the voltage on inversion busMonitoring in real time, in order to process in time according to monitoring result.
Step S102: calculate the first difference between this actual bus voltage and target bus voltage.
Wherein, this target bus voltage is the minimum voltage meeting inverter success inversion, and it can basisThe current electric grid voltage detected is calculated, and formula used can be: target bus voltage=current electric gridVoltage * 1.414+ allowance, this allowance can determine according to actual needs, such as, when current electric grid being detectedWhen voltage is 230V, this target bus voltage can be 230*1.414+25=350V, and wherein, 25V isAllowance.
It should be noted that in actual applications, due to the existence of voltage ripple of power network, thus, targetBusbar voltage is not fixed on one and determines in value, and it can change along with the fluctuation of line voltage, but beginsKeep the minimum voltage that can meet inversion success demand eventually.
Step S103: judge whether the absolute value of this first difference is more than the first voltage threshold, the most thenPerform step S104；If it is not, then return step S101.
In the present embodiment, in order to avoid to the frequent adjustment of the electric current of inductance element in inverter, can be forThe target bus voltage of current electric grid voltage arranges the first voltage threshold, when itself and the actual bus monitoredWhen difference between voltage is in the range of this first voltage threshold, then the current bus on explanation inversion busVoltage not only meets the minimum inversion busbar voltage of reliable inversion, and will not be to being connected in parallel on inversion busOn electric capacity cause damage, it is not necessary to carry out subsequent adjustment operation.
Otherwise, the difference between this target bus voltage and the actual bus voltage monitored more than zero andDuring more than the first voltage threshold, illustrate that the current busbar voltage on inversion bus cannot meet reliable inversionMinimum inversion busbar voltage, inverter cannot normally work；And when this target bus voltage with monitorDifference between actual bus voltage less than zero and not in the range of this first voltage threshold, then illustrates nowCurrent busbar voltage on inversion bus is too high, although meet the minimum inversion busbar voltage of reliable inversion,But, the bus capacitor being connected in parallel on inversion bus can be made to damage, thus affect the safe operation of inverter.
Wherein, the first voltage threshold can determine according to actual needs, and its concrete numerical value is not limited by the present inventionFixed.As when inversion busbar voltage is strictly controlled by needs, this first voltage threshold can be zero, i.e. onlyHave when the actual bus voltage on inversion bus is equal to target bus voltage, just operate without subsequent adjustment.
Step S104: utilize the target current value of inductance element in this first mathematic interpolation inverter.
Step S105: according to the current flow of inductance element in this target current value regulation inverter, untilThe absolute value of the difference between the actual bus voltage and the described target bus voltage that monitor is not more than describedFirst voltage threshold.
The first difference in the present embodiment, between the target bus voltage that actual bus voltage is correspondingAbsolute value more than the first voltage threshold time, can be by the electric current of inductance element in regulation inverter, to changeBecome the energy from the extraction of inversion bus, change the energy storage of bus capacitor, thus change the voltage of bus capacitorI.e. change inversion busbar voltage.
Concrete, in the case of the absolute value of the first difference is more than the first voltage threshold, when actual busVoltage is more than target bus voltage, controls the electric current of inductance element in inverter and increases, i.e. increases from inversionThe energy of extraction on bus, reduces the energy storage of bus capacitor, so that inversion busbar voltage reduces, directlyIt is not more than the first voltage threshold to the difference between the actual bus voltage monitored and described target bus voltageValue；When actual bus voltage is less than target bus voltage, control the electric current of inductance element in inverter and reduce,I.e. reduce the energy of extraction from inversion bus, so that inversion busbar voltage increases, until monitoringActual bus voltage and described target bus voltage between the absolute value of difference be not more than the first voltage thresholdValue.
Preferably, when combining inverter control block diagram as shown in Figure 3 time, i.e. grid-connected inverse shown in Fig. 2On the basis of becoming device control block diagram, access one at inversion bus and have the second of boosting and buck functionalityDC/DC changer, and connect an energy-storage battery Bat at the 2nd DC/DC converter output terminal.The present inventionThe control method that embodiment is provided is equally applicable, Fig. 3 control structure under, the controlling party of its correspondenceMethod is in addition to protection above steps, it is also possible to including:
Detect grid-connected power and bearing power in real time, when the grid-connected power detected is more than bearing power,This energy-storage battery Bat will be charged by the present embodiment, now, owing to the tank voltage of energy-storage battery is maximumValue (such as 48V energy-storage battery) is more much smaller than inversion busbar voltage, thus, available 2nd DC/DCAfter actual bus voltage is depressurized to nominal charging voltage (as being 48V by 350V transformation) by changer, thenIt is delivered to energy-storage battery Bat, in this process, owing to inverter side has carried out voltage stabilizing to inversion busbar voltageProcess, thus reduce the transformation ratio of the 2nd DC/DC changer, and then expand the 2nd DC/DC conversionThe parts selection of device, improves system effectiveness simultaneously.
In like manner, when the grid-connected power detected is less than bearing power, the energy-storage battery Bat in the present embodimentTo discharge to inversion busbar voltage, now, owing to inversion busbar voltage has been carried out at voltage stabilizing by inverter sideReason, thus reduce the tank voltage that energy-storage battery Bat exports by the 2nd DC/DC changer and boostThe transformation ratio of processing procedure, and then expand the parts selection of the 2nd DC/DC changer, improve systemEfficiency.
As another embodiment of the present invention, when collect each variable (as inversion busbar voltage, PV voltage,The electric current etc. of voltage component) when reaching the maximum protection value of its correspondence, warning message can be exported.Wherein,This warning message can be the flicker of different display lamp, buzzer, or comprises the voice of suggestion contentInformation etc., this is not especially limited by the present invention.
Based on above-mentioned analysis, the embodiment of the present invention is by carrying out reality to the actual bus voltage of inverter busTime monitoring, and calculate first difference of this actual bus voltage and target bus voltage, when determine this firstWhen the absolute value of difference is more than the first voltage threshold, utilize inductance element in this first mathematic interpolation inverterBus current value, afterwards, regulate the current electricity of inductance element in this inverter according to this target current valueStream, so that the absolute value of the difference between actual bus voltage and target bus is not more than the first voltageThreshold value, it is to avoid make the capacitance damage being connected in parallel on inversion bus because of the overtension of inversion bus,Solve the problem reducing inversion conversion efficiency because inversion busbar voltage is too high in prior art simultaneously.
As shown in Figure 4, for the schematic flow sheet of another kind control method of grid-connected inverter embodiment of the present invention,
In actual applications, once PV plate is started working, system will detector output actual PV electricityPressure, such as the description in above-described embodiment, is low pressure when it exports PV voltage, and actual PV voltage is less thanDuring target bus voltage, by a DC/DC changer, it will be carried out boosting process, until it is more than meshMark inversion busbar voltage, now the voltage-stabilizing system of inverter side and the voltage-stabilizing system of PV side will carry out voltage stabilizing simultaneouslyProcessing, wherein, the voltage stabilizing process of inverter side can refer to above-described embodiment, the most no longer describes in detail, and PV sideVoltage stabilizing process can be the following step of this enforcement；And when the PV voltage that it exports is high pressure, the most in factWhen border PV voltage is more than target bus voltage, a DC/DC changer does not works, and PV plate directly passes throughBypass mode is inversion bussed supply, so that actual bus voltage is more than target bus voltage, now,The voltage-stabilizing system of inverter side also will carry out voltage stabilizing process to inversion busbar voltage, and the voltage stabilizing of inverter side processedJourney can be found in above-described embodiment, the most no longer describes in detail, when inversion busbar voltage voltage stabilizing value is preset expectation PVDuring voltage, its output PV voltage also will be entered by the voltage-stabilizing system of PV plate side according to a DC/DC changerRow voltage stabilizing processes, and concrete steps may include that
Step S401: monitor the actual PV voltage of the PV plate output corresponding with inverter.
Wherein, in the present invention, once this step S401 of system start-up will perform.
Step S402: this PV plate is carried out MPPT scanning, determines the actual expectation PV electricity of this PV platePressure.
In the actual application of photovoltaic parallel in system, each PV plate has a DC/DC conversion of correspondenceDevice, is used for carrying out MPPT (Maximum Power Point Tracking, MPPT maximum power point tracking) and sweepsRetouch, i.e. by the voltage of this PV plate of disturbance, determine maximum power point, then corresponding PV voltage is realityBorder expectation PV voltage.
Step S403: calculate the 3rd difference of actual PV voltage and this actual expectation PV voltage monitored.
Step S404: judge whether the absolute value of the 3rd difference is more than the second voltage threshold, the most thenPerform step S405, if it is not, then return step S401.
Wherein, the second voltage threshold can determine according to actual needs, and the present invention implements not limit its toolBody numerical value, as when controlling strict to the voltage stabilizing of PV plate, this second voltage threshold can be zero.
Step S405: utilize the 3rd difference to adjust the DC/DC being connected with this PV plate outfan and becomeThe current flow of inductance element in parallel operation, until the actual PV voltage monitored and actual expectation PV voltageThe absolute value of difference be not more than described second voltage threshold.
Concrete, in the case of the absolute value of the 3rd difference is more than the second voltage threshold, as actual PVWhen voltage is more than reality expectation PV voltage, control the current electricity of inductance element in a DC/DC changerStream increases, otherwise, when actual PV voltage is less than reality expectation PV voltage, controls a DC/DC and becomeIn parallel operation, the current flow of inductance element reduces, to reach the purpose of stable PV voltage.
As another embodiment of the present invention, the control method that the embodiment of the present invention is provided is also applied for Fig. 3Shown control structure, now in addition to above steps, it is also possible to including:
Detection bearing power and the grid-connected power of inverter, and judge that whether this grid-connected power is more than loadPower, if so, utilizes the 2nd DC/DC changer being connected with inversion bus to be charged energy-storage battery.If this grid-connected power is less than bearing power, energy-storage battery Bat will discharge, wherein, and this energy-storage battery BatThe detailed process of discharge and recharge can be found in the corresponding part of above-described embodiment, the present invention no longer repeats at this.
Preferably, energy-storage battery is being charged or in energy-storage battery discharge process, it is also possible to monitoring shouldThe physical holding of the stock capacity of energy-storage battery, when this physical holding of the stock capacity reaches the maximum storage appearance of this energy-storage batteryDuring amount, this energy-storage battery is stopped charging；Appearance is stored when physical holding of the stock capacity reaches the minimum of energy-storage batteryDuring amount, control this energy-storage battery and stop electric discharge.
As can be seen here, in order to be further ensured that stablizing of inversion busbar voltage, the present embodiment is by PV plateThe actual PV voltage of output is monitored, and the 3rd judged between itself and actual expectation PV voltageWhen the absolute value of voltage difference is more than the second voltage threshold, by adjusting the be connected with this PV plate outfanThe current flow of inductance element in one DC/DC changer so that PV plate output PV voltage withThe absolute value of the difference of actual expectation PV voltage is not more than the second voltage threshold.
As it is shown in figure 5, be the structured flowchart of the present invention a kind of combining inverter control system embodiment, shouldSystem may include that PV plate 501, input are connected with PV plate 501 outfan, outfan and inversionDevice 502 input connects, and has boosting and buck functionality and PV plate is carried out MPPT scanning, determiningOneth DC/DC changer 503 of the actual expectation PV voltage of described PV plate, is connected in parallel on this inverterThe storage capacitor C of 502 inputs, this inverter 502 outfan is connected in parallel on electrical network.
Wherein, a DC/DC changer 503 for the PV voltage of PV plate output is boosted orBlood pressure lowering processes, and maximal power tracing is concrete, when the output of PV plate be low pressure time, a DC/DCChanger 503 carries out boosting process to it, otherwise, when PV plate output be high pressure time, a DC/DCChanger 503 carries out blood pressure lowering process to it, carries out MPPT scanning simultaneously, to determine the reality of this PV plateExpect PV voltage.
It should be noted that the concrete structure of a DC/DC changer 503 belong to known in this field oftenKnowing, the present invention is not described in detail in this.
In addition, also include being connected with storage capacitor C two ends, the actual bus of monitoring inverter busFirst monitoring device 504 of voltage.In the actual application of the present embodiment, this first monitoring device 504 is permissibleIncluding voltage sensor or transformer etc..
It is connected with this first monitoring device 504 and inverter 502, receives this first monitoring device 504 defeatedThe actual bus voltage gone out, and calculate the first difference between this actual bus voltage and target bus voltage,When the absolute value judging described first difference is more than the first voltage threshold, utilize described first difference meterCalculate the target current value of inductance element in described inverter, afterwards, regulate inversion according to this target current valueThe current flow of inductance element in device 502, until the actual bus voltage monitored and described target busThe absolute value of the difference between voltage is not more than the first control device 505 of the first voltage threshold.
Wherein, this first control device 505 can include multiple controller, in the present embodiment, will controlDevice 1 processed, as ring controller in this inverter side, utilizes this controller 1 to the inductance element in inverterElectric current is controlled, to realize the adjustment to inversion busbar voltage；Using controller 2 as outside this inverter sideRing controller, utilizes controller 2 to be controlled the capacity cell in inverter, so that inversion bus is electricIt is this inverter side that the difference of pressure and target inversion busbar voltage is not more than the first voltage threshold, i.e. controller 2Outer ring controller.
As another embodiment of the present invention, this system can also include:
It is connected with PV plate 501 outfan, the second prison of the actual PV voltage of monitoring PV plate 501 outputSurvey device.
Wherein, this second monitoring device can be voltage sensor or transformer etc..
It is connected with the second monitoring device and a DC/DC changer 503, calculates the second monitoring device and sendThe 3rd difference of actual PV voltage and actual expectation PV voltage, when the absolute value determining the 3rd differenceDuring more than the second voltage threshold, the 3rd difference is utilized to adjust inductance unit in a DC/DC changer 503The current flow of part, until the actual PV voltage monitored and the described actual difference expecting PV voltageAbsolute value is not more than the second control device of the second voltage threshold.
In the present embodiment, this second control device can include multiple controller, concrete, by controller 3As interior ring controller, controller 4 is as outer ring controller, when judging the absolute of above-mentioned 3rd differenceWhen value is more than the second voltage threshold, the preset algorithm in controller 4 is utilized to obtain expecting inductive current, itAfter, utilize this controller 3 to control the electric current of inductance element in a DC/DC changer 503 so that it is to reachTo this expectation inductive current, thus realize the control to PV voltage.
Preferably, this combining inverter control system can also include alarm device, for detecting isDuring system fault (such as phenomenons such as overvoltage and/or mistake streams), export warning message.Concrete, this alarm deviceCan be buzzer, voice module or display lamp etc., this present invention is not especially limited.
As can be seen here, the embodiment of the present invention is by the actual bus electricity of the first monitoring device detection inversion busPressure, and it is sent to first control device, when this first control device judges this actual bus voltage and meshWhen the absolute value of the first difference between mark busbar voltage is more than the first voltage threshold, utilize this first differenceCalculate inductance element target current value in inverter, adjust this inverter according to this target current value afterwardsThe current flow of middle inductance element, so that the actual bus voltage monitored and described target bus voltageThe absolute value of difference is not more than the first voltage threshold, thus avoids and make because of the overtension of inversion busThe storage capacitor must being connected in parallel on inversion bus damages, and solves in prior art because of inversion bus electricity simultaneouslyThe problem pressing through height and reduce inversion conversion efficiency.
As shown in Figure 6, for the structured flowchart of another kind combining inverter control system embodiment of the present invention,This system may include that PV plate 601；Input is connected with PV plate 601 outfan, and outfan is with inverseBecome device 602 input to connect, there is boosting and buck functionality and PV plate is carried out MPPT scanning, reallyOneth DC/DC changer 603 of the actual expectation PV voltage of fixed described PV plate；It is connected in parallel on this inverterThe storage capacitor C of 602 inputs；One end is connected with inverter 602 input, has boosting and blood pressure lowering merit2nd DC/DC changer 604 of energy；The energy storage being connected with the other end of the 2nd DC/DC changer 604Battery 605.
Wherein, when energy-storage battery 605 is charged by electrical network, the 2nd DC/DC changer 604 is for inverseVariable bus voltage carries out blood pressure lowering process, as 350V becomes 48V；When this energy-storage battery 606 discharges to electrical network,2nd DC/DC changer 604 is for carrying out boosting process to inversion busbar voltage, due to inversion busVoltage is stabilized in the minimum voltage needed for inversion, thus reduces the transformation of the 2nd DC/DC changerRatio, and then expand the parts selection scope of the 2nd DC/DC changer, improve system effectiveness simultaneously.
Preferably, the 2nd DC/DC changer 604 can be the two-way DC/DC conversion of two-stage boostingDevice or the two-way DC/DC changer of isolated form full-bridge transformer device structure, to reach the purpose of high step-up ratio.
In addition to this it is possible to include being connected with storage capacitor C two ends, the reality of monitoring inverter busFirst monitoring device 606 of busbar voltage.
Wherein, this first monitoring device 606 can include voltage sensor or transformer etc..
It is connected with this first monitoring device 606 and inverter 602, receives this first monitoring device 606 defeatedThe actual bus voltage gone out, and calculate the first difference between this actual bus voltage and target bus voltage,When the absolute value of this first difference is more than the first voltage threshold, this first mathematic interpolation is utilized to go out inverterAfter the target current value of middle inductance element, according to inductance element in this target current value regulation inverter 602Current flow, until the actual bus voltage monitored and the difference of described target bus voltage is absoluteValue is not more than the first control device 607 of the first voltage threshold.
Such as the record of above-described embodiment, this first control device 607 can include two controllers.
It is connected with PV plate 601 outfan, the second prison of the actual PV voltage of monitoring PV plate 601 outputSurvey device 608.
Wherein, this second monitoring device 608 can include voltage sensor or transformer etc..
It is connected with the second monitoring device 608 and a DC/DC changer 603, calculates the second monitoring device 608The actual PV voltage sent and actual the 3rd difference expecting PV voltage, and at the absolute value of the 3rd differenceDuring more than the second voltage threshold, the 3rd difference is utilized to adjust inductance element in a DC/DC changer 603Current flow, until the difference of the actual PV voltage monitored and actual expectation PV voltage is not more than secondThe second control device 609 of voltage threshold.
In the present embodiment, this second control device 609 can include two controllers, and concrete control process canSeeing above-described embodiment corresponding part, the present embodiment is not described in detail in this.
It is connected with energy-storage battery 605 outfan, monitors the 3rd monitoring of the tank voltage of this energy-storage battery 605Device 610, in the present embodiment, the 3rd monitoring device 610 can be voltage sensor.
Preferably, system can also include the display device being connected with the 3rd monitoring device 610, is used for showingShow the current tank voltage of this energy-storage battery 605.
The 3rd control device 611 being connected with the 2nd DC/DC changer 604, in the present embodiment, the 3rdControl device 611 and can include multiple controller, using controller 5 as ring controller in battery side, controlDevice 6 is as the outer ring controller of battery side, when energy-storage battery 605 discharges, it is not necessary to consider outer voltage, onlyNeed to utilize controller 5 that the electric current of the inductance element in the 2nd DC/DC changer 604 is adjusted i.e.Can, when the 3rd monitoring device 610 detects that the current storage volume of this energy-storage battery 605 reaches its minimum storageWhen depositing capacity, control this energy-storage battery 605 and stop electric discharge.
And when being charged this energy-storage battery, available controller 5 and controller 6 act on jointly, when theThree monitoring devices 611 detect when the current storage volume of this energy-storage battery 606 reaches maximum storage capacity,Control this energy-storage battery 605 and stop charging.Wherein, controller 6 is for being controlled energy-storage battery voltage.
Preferably, this combining inverter control system can also include and first control device 607 and/orTwo control device 609 and/or the 3rd controls the alarm device that device 611 is connected, when determining that system occurredWhen pressing and/or cross stream, export warning message.
Concrete, this alarm device can be buzzer, and voice module or display lamp etc., to this present inventionIt is not especially limited.
Preferably, the controller involved by the above embodiment of the present invention can be PI controller.
Understanding based on above-mentioned analysis, the embodiment of the present invention controls inversion busbar voltage by first control deviceStable, second control device controls the PV voltage stabilization of PV plate output, thus minimum needed for meeting inversionOn the premise of busbar voltage, PV plate is carried out maximal power tracing, control device by the 3rd and control energy storageBattery charging and discharging, it is achieved the purpose to PV plate energy storage, simultaneously when inverter power is too low, mends in timeFill power.
It should be noted that in the various embodiments described above of the present invention, except above-mentioned described device, also may be usedTo include connection member for connecting each device etc., the present invention will not enumerate at this, as long as notIt is that those skilled in the art pay creative work and determine, belongs to technical solution of the present invention.
It addition, for the various embodiments described above include operation or entities such as " first " " second ", itsOnly it is used for distinguishing these operation or entities, the most there is not orbution, merely to become apparent fromGround understands technical solution of the present invention.
In this specification, each embodiment uses the mode gone forward one by one to describe, and each embodiment stressesBeing the difference with other embodiments, between each embodiment, identical similar portion sees mutually.For system disclosed in embodiment, owing to it corresponds to the method disclosed in Example, so describingFairly simple, relevant part sees method part and illustrates.
Described above to the disclosed embodiments, makes professional and technical personnel in the field be capable of or usesThe present invention.Multiple amendment to these embodiments will be aobvious and easy for those skilled in the artSee, generic principles defined herein can without departing from the spirit or scope of the present invention,Realize in other embodiments.Therefore, the present invention is not intended to be limited to the embodiments shown herein,And it is to fit to the widest scope consistent with principles disclosed herein and features of novelty.