CN104158223B - A kind of control method of grid-connected inverter and system - Google Patents
A kind of control method of grid-connected inverter and system Download PDFInfo
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- CN104158223B CN104158223B CN201410439901.0A CN201410439901A CN104158223B CN 104158223 B CN104158223 B CN 104158223B CN 201410439901 A CN201410439901 A CN 201410439901A CN 104158223 B CN104158223 B CN 104158223B
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Abstract
This application provides a kind of control method of grid-connected inverter and device, by the actual bus voltage of inverter bus is monitored in real time, when determining this actual bus voltage absolute value with the first difference of target bus voltage more than the first voltage threshold, utilize the target current value of inductance element in this first mathematic interpolation inverter, wherein, this target bus voltage is the minimum voltage meeting described inverter success inversion, afterwards, the current flow of this inductance element is regulated according to this target current value, so that the absolute value of the difference between actual bus voltage and target bus is not more than the first voltage threshold, thus avoid and make, because of the overtension of inversion bus, the capacitance damage being connected in parallel on inversion bus, solve the problem reducing inversion conversion efficiency because inversion busbar voltage is too high in prior art simultaneously.
Description
Technical field
The present invention relates to the technical field of inverter in grid-connected photovoltaic system, more particularly, it relates to
A kind of control method of grid-connected inverter and system.
Background technology
At present, in grid-connected photovoltaic system, the output of PV plate PV voltage less than needed for inversion
During minor mistake in treatment variable bus voltage, in order to ensure that inversion busbar voltage reaches the minimum voltage needed for inversion, so that
Inverter normally works, and is the most all to access DC/DC at PV (Photo Voltaic, light cell) plate outfan
Changer, carries out boosting process, so that the voltage after Chu Liing reaches to the PV voltage of PV plate output
Minimum amount of voltage that needed for inversion.
But, for existing this inverter, needed for the PV voltage of PV plate output is more than inversion
During minor mistake in treatment variable bus voltage, the DC/DC changer with boost function will quit work, now, and PV plate
Direct is inversion bussed supply by bypass mode, then inversion busbar voltage is equal to PV voltage, although meet
Minimum voltage needed for inversion, but, inversion will be reduced owing to now inversion busbar voltage is too high
Conversion efficiency.
Summary of the invention
In view of this, the invention provides a kind of control method of grid-connected inverter and system, solve existing
Technology 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 bus
Voltage 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 monitoring
Actual bus voltage and described target bus voltage between the absolute value of difference be not more than described first electricity
Pressure 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 inverter
The current flow of element；
When described actual bus voltage is less than described target bus voltage, reduce inductance in described inverter
The 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, and
When 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 voltage
3rd 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 outfan
The current flow of inductance element in changer, until the actual PV voltage detected and described actual expectation
The 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 processed
When 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 voltage
4th 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 outfan
The current flow of inductance element in changer, until the actual PV voltage detected and described actual expectation
The 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 lowering
To 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 exported
It 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, described
Method 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 storage
Charging 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 storage
Electric 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 terminal
Storage capacitor, described system also includes:
Input is connected with PV plate outfan, and outfan is connected with described inverter input terminal, has boosting
And buck functionality, and described PV plate is carried out MPPT scanning, determine the actual expectation of described PV plate
Oneth 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 bus
Device；
It is connected with described first monitoring device and described inverter, receives the institute of this first monitoring device output
State 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 interpolation
The target current value of inductance element in described inverter, and regulate described inversion according to described target current value
The current flow of inductance element in device, until the actual bus voltage monitored and described target bus voltage
Between 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 output
Survey device；
It is connected with described second monitoring device and a described DC/DC changer, calculates the second monitoring device
The actual PV voltage sent and actual the 3rd difference expecting PV voltage, when judging described 3rd difference
Absolute value more than the second voltage threshold time, utilize described 3rd difference adjust described oneth DC/DC conversion
The current flow of inductance element in device, until the actual PV voltage monitored and described actual expectation PV electricity
The 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 functionality
Device；
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 and
System, by monitoring in real time the actual bus voltage of inverter bus, when judging that this reality is female
When the absolute value of the first difference of line voltage and target bus voltage is more than the first voltage threshold, utilize this
One mathematic interpolation goes out the target current value of inductance element in inverter, and wherein, this target bus voltage is full
The minimum voltage of the described inverter success inversion of foot, afterwards, the present invention is inverse to this according to this target current value
Become the regulation of the current flow of inductance element in device, thus reduce between actual bus voltage and target bus
The first difference, until the absolute value of this first difference is not more than the first voltage threshold, it is to avoid because of inversion
The overtension of bus (i.e. more than the minimal reverse variable bus voltage needed for inversion) and make to be connected in parallel on inversion
Capacitance damage on bus, solves in prior art simultaneously and reduces inversion because inversion busbar voltage is too high
The problem of conversion efficiency.
Accompanying drawing explanation
In order to be illustrated more clearly that the embodiment of the present invention or technical scheme of the prior art, below will be to reality
Execute the required accompanying drawing used in example or description of the prior art to be briefly described, it should be apparent that below,
Accompanying drawing in description is only embodiments of the invention, for those of ordinary skill in the art, not
On the premise of paying creative work, it is also possible to obtain other accompanying drawing according to the accompanying drawing provided.
Fig. 1 is the schematic flow sheet of the present invention a kind of grid-connected control method embodiment；
Fig. 2 is the control block diagram of a kind of combining inverter of the present invention；
Fig. 3 is the control block diagram of another kind combining inverter of the present invention；
Fig. 4 is the schematic flow sheet of another kind grid-connected control method embodiment of the present invention；
Fig. 5 is the structured flowchart of the present invention a kind of grid-connection control system embodiment；
Fig. 6 is the structured flowchart of another kind grid-connection control system embodiment of the present invention.
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 out
Clearly and completely describe, it is clear that described embodiment is only a part of embodiment of the present invention, and
It is not all, of embodiment.Based on the embodiment in the present invention, those of ordinary skill in the art are not doing
Go 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 bus
Border busbar voltage is monitored in real time, when judging the first of this actual bus voltage and target bus voltage
When the absolute value of difference is more than the first voltage threshold, utilize inductance element in this first mathematic interpolation inverter
Target current value, wherein, this target bus voltage is the minimum electricity meeting described inverter success inversion
Pressure, 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 absolute
Value 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 female
Capacitance damage on line, solves in prior art simultaneously and reduces inversion turn because inversion busbar voltage is too high
The 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, should
The 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 old
DC/DC converter output terminal connects the inversion bus i.e. input of single-phase inverter, wherein, inversion bus
A 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 about
230*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 opened
When beginning work output PV voltage is low pressure (i.e. PV voltage be less than minimum inversion busbar voltage), will be by the
One DC/DC changer carries out boosting process to PV voltage, it will usually more than 350V (i.e. inversion bus
Voltage is more than 350V) after, start inverter side voltage-stabilizing system and the voltage stabilizing of inversion busbar voltage is processed, simultaneously
Control a DC/DC changer and PV plate is carried out MPPT scanning, in order to PV side voltage-stabilizing system is to this
PV 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 inversion
Busbar voltage) time, a DC/DC changer does not works, and PV plate is directly inversion by bypass mode
Bussed supply, then the actual bus voltage of inverter side is more than target equal to PV voltage, i.e. actual bus voltage
Busbar voltage, processes starting inverter side voltage-stabilizing system the voltage stabilizing of inversion busbar voltage, controls the simultaneously
One DC/DC changer carries out MPPT scanning to PV plate, in order to PV side voltage-stabilizing system is to this PV electricity
Pressure 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 bus
Monitoring 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 basis
The current electric grid voltage detected is calculated, and formula used can be: target bus voltage=current electric grid
Voltage * 1.414+ allowance, this allowance can determine according to actual needs, such as, when current electric grid being detected
When voltage is 230V, this target bus voltage can be 230*1.414+25=350V, and wherein, 25V is
Allowance.
It should be noted that in actual applications, due to the existence of voltage ripple of power network, thus, target
Busbar voltage is not fixed on one and determines in value, and it can change along with the fluctuation of line voltage, but begins
Keep 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 then
Perform 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 for
The target bus voltage of current electric grid voltage arranges the first voltage threshold, when itself and the actual bus monitored
When difference between voltage is in the range of this first voltage threshold, then the current bus on explanation inversion bus
Voltage not only meets the minimum inversion busbar voltage of reliable inversion, and will not be to being connected in parallel on inversion bus
On 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 and
During more than the first voltage threshold, illustrate that the current busbar voltage on inversion bus cannot meet reliable inversion
Minimum inversion busbar voltage, inverter cannot normally work；And when this target bus voltage with monitor
Difference between actual bus voltage less than zero and not in the range of this first voltage threshold, then illustrates now
Current 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 invention
Fixed.As when inversion busbar voltage is strictly controlled by needs, this first voltage threshold can be zero, i.e. only
Have 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, until
The absolute value of the difference between the actual bus voltage and the described target bus voltage that monitor is not more than described
First voltage threshold.
The first difference in the present embodiment, between the target bus voltage that actual bus voltage is corresponding
Absolute value more than the first voltage threshold time, can be by the electric current of inductance element in regulation inverter, to change
Become the energy from the extraction of inversion bus, change the energy storage of bus capacitor, thus change the voltage of bus capacitor
I.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 bus
Voltage is more than target bus voltage, controls the electric current of inductance element in inverter and increases, i.e. increases from inversion
The energy of extraction on bus, reduces the energy storage of bus capacitor, so that inversion busbar voltage reduces, directly
It is not more than the first voltage threshold to the difference between the actual bus voltage monitored and described target bus voltage
Value；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 monitoring
Actual bus voltage and described target bus voltage between the absolute value of difference be not more than the first voltage threshold
Value.
Preferably, when combining inverter control block diagram as shown in Figure 3 time, i.e. grid-connected inverse shown in Fig. 2
On the basis of becoming device control block diagram, access one at inversion bus and have the second of boosting and buck functionality
DC/DC changer, and connect an energy-storage battery Bat at the 2nd DC/DC converter output terminal.The present invention
The control method that embodiment is provided is equally applicable, Fig. 3 control structure under, the controlling party of its correspondence
Method 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 maximum
Value (such as 48V energy-storage battery) is more much smaller than inversion busbar voltage, thus, available 2nd DC/DC
After actual bus voltage is depressurized to nominal charging voltage (as being 48V by 350V transformation) by changer, then
It is delivered to energy-storage battery Bat, in this process, owing to inverter side has carried out voltage stabilizing to inversion busbar voltage
Process, thus reduce the transformation ratio of the 2nd DC/DC changer, and then expand the 2nd DC/DC conversion
The 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 embodiment
To discharge to inversion busbar voltage, now, owing to inversion busbar voltage has been carried out at voltage stabilizing by inverter side
Reason, thus reduce the tank voltage that energy-storage battery Bat exports by the 2nd DC/DC changer and boost
The transformation ratio of processing procedure, and then expand the parts selection of the 2nd DC/DC changer, improve system
Efficiency.
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 content
Information 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 bus
Time monitoring, and calculate first difference of this actual bus voltage and target bus voltage, when determine this first
When the absolute value of difference is more than the first voltage threshold, utilize inductance element in this first mathematic interpolation inverter
Bus current value, afterwards, regulate the current electricity of inductance element in this inverter according to this target current value
Stream, so that the absolute value of the difference between actual bus voltage and target bus is not more than the first voltage
Threshold 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 electricity
Pressure, such as the description in above-described embodiment, is low pressure when it exports PV voltage, and actual PV voltage is less than
During target bus voltage, by a DC/DC changer, it will be carried out boosting process, until it is more than mesh
Mark inversion busbar voltage, now the voltage-stabilizing system of inverter side and the voltage-stabilizing system of PV side will carry out voltage stabilizing simultaneously
Processing, wherein, the voltage stabilizing process of inverter side can refer to above-described embodiment, the most no longer describes in detail, and PV side
Voltage stabilizing process can be the following step of this enforcement；And when the PV voltage that it exports is high pressure, the most in fact
When border PV voltage is more than target bus voltage, a DC/DC changer does not works, and PV plate directly passes through
Bypass 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 processed
Journey can be found in above-described embodiment, the most no longer describes in detail, when inversion busbar voltage voltage stabilizing value is preset expectation PV
During voltage, its output PV voltage also will be entered by the voltage-stabilizing system of PV plate side according to a DC/DC changer
Row 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 plate
Pressure.
In the actual application of photovoltaic parallel in system, each PV plate has a DC/DC conversion of correspondence
Device, is used for carrying out MPPT (Maximum Power Point Tracking, MPPT maximum power point tracking) and sweeps
Retouch, i.e. by the voltage of this PV plate of disturbance, determine maximum power point, then corresponding PV voltage is reality
Border 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 then
Perform 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 tool
Body 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 become
The current flow of inductance element in parallel operation, until the actual PV voltage monitored and actual expectation PV voltage
The 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 PV
When voltage is more than reality expectation PV voltage, control the current electricity of inductance element in a DC/DC changer
Stream increases, otherwise, when actual PV voltage is less than reality expectation PV voltage, controls a DC/DC and become
In 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. 3
Shown 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 load
Power, 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 Bat
The 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 should
The 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 battery
During amount, this energy-storage battery is stopped charging；Appearance is stored when physical holding of the stock capacity reaches the minimum of energy-storage battery
During 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 plate
The actual PV voltage of output is monitored, and the 3rd judged between itself and actual expectation PV voltage
When the absolute value of voltage difference is more than the second voltage threshold, by adjusting the be connected with this PV plate outfan
The current flow of inductance element in one DC/DC changer so that PV plate output PV voltage with
The 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, should
System may include that PV plate 501, input are connected with PV plate 501 outfan, outfan and inversion
Device 502 input connects, and has boosting and buck functionality and PV plate is carried out MPPT scanning, determining
Oneth DC/DC changer 503 of the actual expectation PV voltage of described PV plate, is connected in parallel on this inverter
The 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 or
Blood pressure lowering processes, and maximal power tracing is concrete, when the output of PV plate be low pressure time, a DC/DC
Changer 503 carries out boosting process to it, otherwise, when PV plate output be high pressure time, a DC/DC
Changer 503 carries out blood pressure lowering process to it, carries out MPPT scanning simultaneously, to determine the reality of this PV plate
Expect PV voltage.
It should be noted that the concrete structure of a DC/DC changer 503 belong to known in this field often
Knowing, 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 bus
First monitoring device 504 of voltage.In the actual application of the present embodiment, this first monitoring device 504 is permissible
Including voltage sensor or transformer etc..
It is connected with this first monitoring device 504 and inverter 502, receives this first monitoring device 504 defeated
The 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 meter
Calculate the target current value of inductance element in described inverter, afterwards, regulate inversion according to this target current value
The current flow of inductance element in device 502, until the actual bus voltage monitored and described target bus
The 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 control
Device 1 processed, as ring controller in this inverter side, utilizes this controller 1 to the inductance element in inverter
Electric current is controlled, to realize the adjustment to inversion busbar voltage；Using controller 2 as outside this inverter side
Ring controller, utilizes controller 2 to be controlled the capacity cell in inverter, so that inversion bus is electric
It 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 2
Outer 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 output
Survey 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 send
The 3rd difference of actual PV voltage and actual expectation PV voltage, when the absolute value determining the 3rd difference
During more than the second voltage threshold, the 3rd difference is utilized to adjust inductance unit in a DC/DC changer 503
The current flow of part, until the actual PV voltage monitored and the described actual difference expecting PV voltage
Absolute 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 3
As interior ring controller, controller 4 is as outer ring controller, when judging the absolute of above-mentioned 3rd difference
When value is more than the second voltage threshold, the preset algorithm in controller 4 is utilized to obtain expecting inductive current, it
After, utilize this controller 3 to control the electric current of inductance element in a DC/DC changer 503 so that it is to reach
To this expectation inductive current, thus realize the control to PV voltage.
Preferably, this combining inverter control system can also include alarm device, for detecting is
During system fault (such as phenomenons such as overvoltage and/or mistake streams), export warning message.Concrete, this alarm device
Can 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 bus
Pressure, and it is sent to first control device, when this first control device judges this actual bus voltage and mesh
When the absolute value of the first difference between mark busbar voltage is more than the first voltage threshold, utilize this first difference
Calculate inductance element target current value in inverter, adjust this inverter according to this target current value afterwards
The current flow of middle inductance element, so that the actual bus voltage monitored and described target bus voltage
The absolute value of difference is not more than the first voltage threshold, thus avoids and make because of the overtension of inversion bus
The storage capacitor must being connected in parallel on inversion bus damages, and solves in prior art because of inversion bus electricity simultaneously
The 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 inverse
Become device 602 input to connect, there is boosting and buck functionality and PV plate is carried out MPPT scanning, really
Oneth DC/DC changer 603 of the actual expectation PV voltage of fixed described PV plate；It is connected in parallel on this inverter
The storage capacitor C of 602 inputs；One end is connected with inverter 602 input, has boosting and blood pressure lowering merit
2nd DC/DC changer 604 of energy；The energy storage being connected with the other end of the 2nd DC/DC changer 604
Battery 605.
Wherein, when energy-storage battery 605 is charged by electrical network, the 2nd DC/DC changer 604 is for inverse
Variable 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 bus
Voltage is stabilized in the minimum voltage needed for inversion, thus reduces the transformation of the 2nd DC/DC changer
Ratio, 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 boosting
Device 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 bus
First 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 defeated
The 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 inverter
After the target current value of middle inductance element, according to inductance element in this target current value regulation inverter 602
Current flow, until the actual bus voltage monitored and the difference of described target bus voltage is absolute
Value 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 output
Survey 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 608
The actual PV voltage sent and actual the 3rd difference expecting PV voltage, and at the absolute value of the 3rd difference
During more than the second voltage threshold, the 3rd difference is utilized to adjust inductance element in a DC/DC changer 603
Current flow, until the difference of the actual PV voltage monitored and actual expectation PV voltage is not more than second
The second control device 609 of voltage threshold.
In the present embodiment, this second control device 609 can include two controllers, and concrete control process can
Seeing 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 605
Device 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 showing
Show 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 3rd
Control device 611 and can include multiple controller, using controller 5 as ring controller in battery side, control
Device 6 is as the outer ring controller of battery side, when energy-storage battery 605 discharges, it is not necessary to consider outer voltage, only
Need 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 storage
When 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 the
Three 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/or
Two control device 609 and/or the 3rd controls the alarm device that device 611 is connected, when determining that system occurred
When 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 invention
It 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 device
Stable, second control device controls the PV voltage stabilization of PV plate output, thus minimum needed for meeting inversion
On the premise of busbar voltage, PV plate is carried out maximal power tracing, control device by the 3rd and control energy storage
Battery charging and discharging, it is achieved the purpose to PV plate energy storage, simultaneously when inverter power is too low, mends in time
Fill power.
It should be noted that in the various embodiments described above of the present invention, except above-mentioned described device, also may be used
To include connection member for connecting each device etc., the present invention will not enumerate at this, as long as not
It 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 ", its
Only it is used for distinguishing these operation or entities, the most there is not orbution, merely to become apparent from
Ground 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 stresses
Being 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 describing
Fairly 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 uses
The present invention.Multiple amendment to these embodiments will be aobvious and easy for those skilled in the art
See, 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.
Claims (7)
1. a control method of grid-connected inverter, it is characterised in that 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 bus
Voltage 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 monitoring
Actual bus voltage and described target bus voltage between the absolute value of difference be not more than described first electricity
Pressure threshold value；
Wherein, 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；
When judging that described second difference more than zero and is more than described first voltage threshold, and in described reality
When busbar 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 voltage
3rd 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 outfan
The current flow of inductance element in changer, until the actual PV voltage detected and described actual expectation
The absolute value of the difference of PV voltage is not more than described second voltage threshold.
Method the most according to claim 1, it is characterised in that in the described inverter of described regulation
The current flow of inductance element include:
When described actual bus voltage is more than described target bus voltage, increase inductance in described inverter
The current flow of element；
When described actual bus voltage is less than described target bus voltage, reduce inductance in described inverter
The current flow of element.
Method the most according to claim 1, it is characterised in that when judging described second difference
Less than zero and absolute value is more than described first voltage threshold, and by described actual PV boost in voltage
When managing and make the absolute value of described first difference be not more than described first voltage threshold, described method is also wrapped
Include:
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 voltage
4th 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 outfan
The current flow of inductance element in changer, until the actual PV voltage detected and described actual expectation
The absolute value of the difference of PV voltage is not more than described tertiary voltage threshold value.
4. according to the method described in any one of claim 1-3, it is characterised in that described method is also wrapped
Include:
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 lowering
To 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 exported
It is depressed into described target bus voltage, is delivered to described inverter.
Method the most according to claim 4, it is characterised in that described energy-storage battery is being carried out
In charging or described energy-storage battery discharge process, described method also includes:
Monitor the physical holding of the stock capacity of described energy-storage battery；
When described physical holding of the stock capacity reaches the maximum storage capacity of described energy-storage battery, to described energy storage
Battery stops charging；
When described physical holding of the stock capacity reaches the minimum storage volume of described energy-storage battery, control described storage
Electric discharge can be stopped by battery.
6. a combining inverter control system, described system includes PV plate and to be connected in parallel on inverter defeated
Enter the storage capacitor of end, it is characterised in that described system also includes:
Input is connected with PV plate outfan, and outfan is connected with described inverter input terminal, has liter
Pressure and buck functionality, and described PV plate is carried out MPPT scanning, determine the reality of described PV plate
Expect a 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 bus
Device；
It is connected with described first monitoring device and described inverter, receives the institute of this first monitoring device output
State actual bus voltage, and it is poor to calculate first between described actual bus voltage and target bus voltage
Value, when the absolute value judging described first difference is more than the first voltage threshold, utilizes this first difference
Calculate the target current value of inductance element in described inverter, and described according to the regulation of described target current value
The current flow of inductance element in inverter, until the actual bus voltage monitored and described target bus
Absolute difference between voltage is 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；
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 output
Survey device；
It is connected with described second monitoring device and a described DC/DC changer, calculates the second monitoring dress
Put the actual PV voltage of transmission and the 3rd difference of actual expectation PV voltage, when judging the described 3rd
When the absolute value of difference is more than the second voltage threshold, described 3rd difference is utilized to adjust a described DC/DC
The current flow of inductance element in changer, until the actual PV voltage monitored and described actual expectation
The absolute value of the difference of PV voltage is not more than the second control device of described second voltage threshold.
System the most according to claim 6, it is characterised in that described system also includes:
One end is connected with described inverter input terminal, and the 2nd DC/DC with boosting and buck functionality becomes
Parallel operation；
The energy-storage battery being connected with the other end of described 2nd DC/DC changer.
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| CN104333213B (en) * | 2014-11-25 | 2018-04-10 | 阳光电源股份有限公司 | Guard method, equipment and system during a kind of PV arrays output overvoltage |
| CN104460818B (en) * | 2014-12-11 | 2017-02-22 | 阳光电源股份有限公司 | Maximum-power-point global scanning method, inverter and photovoltaic system |
| CN104993755A (en) * | 2015-08-03 | 2015-10-21 | 广东威灵电机制造有限公司 | DC voltage control method and system for brushless DC motor |
| CN109802556B (en) * | 2017-11-17 | 2021-01-26 | 丰郅(上海)新能源科技有限公司 | Photovoltaic power generation system with photovoltaic inverter and starting method of inverter |
| CN111756046B (en) * | 2020-07-29 | 2022-02-18 | 阳光电源股份有限公司 | Bus voltage control method, controller and photovoltaic energy storage conversion system |
| CN113746170B (en) * | 2021-09-03 | 2024-02-09 | 阳光电源（上海）有限公司 | Energy storage system and off-grid overload protection method thereof |
| CN114122996A (en) * | 2021-11-25 | 2022-03-01 | 广东电网有限责任公司 | Capacitor maintenance method and device and transformer voltage regulation early warning method and device |
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| CN103730911B (en) * | 2013-12-25 | 2015-08-19 | 常熟开关制造有限公司(原常熟开关厂） | The grid-connected control method of photovoltaic combining inverter and grid-connected photovoltaic system |
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