CN104467016B - A kind of five level photovoltaic inverter precharge control methods and system - Google Patents
A kind of five level photovoltaic inverter precharge control methods and system Download PDFInfo
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- CN104467016B CN104467016B CN201410797550.0A CN201410797550A CN104467016B CN 104467016 B CN104467016 B CN 104467016B CN 201410797550 A CN201410797550 A CN 201410797550A CN 104467016 B CN104467016 B CN 104467016B
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
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- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
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Abstract
This application provides a kind of five level photovoltaic inverters precharge control method and system, when power network enters line precharge to dc-link capacitance, the current voltage of the dc-link capacitance is detected in real time, when it meets preliminary filling condition, disconnect pre-charge circuit, if now dc-link capacitance voltage is not less than the first threshold values, five level photovoltaic inverters are controlled to be operated in three level active patterns, to reduce the dc-link capacitance voltage, when the current voltage of the dc-link capacitance after reduction reaches the second threshold values, control five level photovoltaic inverters to exit after three level active patterns and enter normal grid-connected mode of operation, so as to avoid the appearance that dc-link capacitance voltage is more than its maximum protection voltage condition, it ensure that the normal startup of five level photovoltaic inverters, and then ensure that the reliability service of grid-connected photovoltaic system.
Description
Technical field
The invention mainly relates to the control field of grid-connected photovoltaic system, more particularly to a kind of five level light
Lie prostrate inverter precharge control method and system.
Background technology
Photovoltaic DC-to-AC converter is an important component in grid-connected photovoltaic system, for the direct current for generating PV cell panels
Electricity is converted to and power network is delivered to after alternating current, and in actual applications, in order to improve inversion efficiency, reduces harmonic wave, it will usually make
It is grid-connected with many level photovoltaic inverters, the present invention for five level photovoltaic inverters grid-connected work carry out improvement, this five
Before level photovoltaic inverter is grid-connected, during in order to prevent that five level photovoltaic inverters are grid-connected, power network produces very big impact to it
And the performance of some of which device is influenceed, or even some devices can be damaged, it usually needs power network is to five level photovoltaic inverters
Dc-link capacitance enters line precharge, so as to ensure the reliability service of grid-connected photovoltaic system.
Specifically, the structural representation of the photovoltaic parallel in system based on five level photovoltaic inverters as shown in Figure 1, for
For each phase of the system, its five level photovoltaic inverters input is connected with PV cell panels, and output end passes through filter circuit
It is connected with power network, wherein, five level photovoltaic inverters include：The first DC/DC circuits being connected with PV cell panel positive poles, with PV electricity
2nd DC/DC circuits of pond plate negative pole connection, input respectively with the first DC/DC circuits, the 2nd DC/DC circuits and PV batteries
The both positive and negative polarity connection of plate, the five level inverse conversion units that output end is connected by filter unit with power network, and in five level inverse conversion
Between the switch module SP2 of second positive level of unit and the switch module SN0 of zero level and the second negative level switching molding
Positive pole line capacitance C1 and negative busbar electric capacity C2, pre-charge circuit are parallel between block SN2 and the switch module SN0 of zero level respectively
Input is connected with power network, and output end is connected with positive pole line capacitance C1 and negative busbar electric capacity C2.
Grid-connected photovoltaic system based on said structure, in actual applications, before five level photovoltaic inverters of startup,
Power network will be that positive pole line capacitance C1 and negative busbar electric capacity C2 charges by the pre-charge circuit, so as to prevent that the five level photovoltaic is inverse
When change device is grid-connected, power network produces great impact to it, it is ensured that the safe and reliable operation of grid-connected photovoltaic system.
However, it has been found that in the practical application of grid-connected photovoltaic system, often there is ripple in line voltage
It is dynamic, thus, according to the electrical block diagram shown in Fig. 1 iting can be seen from, power network to dc-link capacitance (i.e. positive pole line capacitance C1 with
Negative busbar electric capacity C2) carry out in pre-charge process, when grid voltage amplitude produces larger fluctuation or larger harmonic wave, direct current is female
Voltage magnitude on line capacitance can also increase therewith, when it exceedes default maximum voltage protection value, five level photovoltaic inverters
Normal startup is will be unable to, so as to have impact on the reliability service of grid-connected photovoltaic system.
The content of the invention
In view of this, the invention provides a kind of five level photovoltaic inverters precharge control method and system, solve
Five level photovoltaic inverters are made not start normally because of dc-link capacitance overtension in the prior art, so as to influence photovoltaic
The technical problem of grid-connected system reliability service.
To achieve these goals, this application provides following technical scheme：
A kind of five level photovoltaic inverter precharge control methods, including：
When power network enters line precharge by pre-charge circuit to the dc-link capacitance of five level photovoltaic inverters, in real time
Detect the current voltage of the dc-link capacitance；
When the current voltage of the dc-link capacitance meets preparatory condition, the pre-charge circuit is controlled to disconnect；
When detecting the pre-charge circuit and disconnecting, the current voltage of the dc-link capacitance is not less than the first threshold values
When, control five level photovoltaic inverter to be operated in three level active patterns, to reduce the current of the dc-link capacitance
Voltage；
When the current voltage for detecting the dc-link capacitance after reduction reaches the second threshold values, the five level light is controlled
Volt inverter, which is exited after the three level actives pattern, enters normal grid-connected mode of operation.
It is preferred that, when detecting the pre-charge circuit and disconnecting, the current voltage of the dc-link capacitance is less than first
During threshold values, five level photovoltaic inverter is controlled to enter normal grid-connected mode of operation.
It is preferred that, line precharge is entered to the dc-link capacitance of five level photovoltaic inverters by pre-charge circuit in power network
During, in addition to：
Line voltage peak value is detected in real time；
When the line voltage peak value fluctuation range exceedes given threshold, the first warning message is exported；
Wherein, first warning message is specially indicator lamp flash signal, buzzer voice signal or includes alarm
The voice signal of content.
It is preferred that, when the current voltage of the dc-link capacitance is not less than the first threshold values, in addition to：Output second is reported
Alert information；
Wherein, second warning message is specially indicator lamp flash signal, buzzer voice signal or includes alarm
The voice signal of content.
It is preferred that, control five level photovoltaic inverter is operated in three level active patterns and is specially：
Control is one-to-one with the second positive level in the five level inverse conversions unit, zero level and the second negative level
Switch module works, so that the dc-link capacitance and second positive level, second negative level and zero level one
One corresponding switch module formation discharge loop.
A kind of five level photovoltaic inverter preliminary filling electric control systems, including
The detection means being connected with the dc-link capacitance of five level photovoltaic inverters, when power network passes through pre-charge circuit pair
When the dc-link capacitance enters line precharge, the current voltage of the dc-link capacitance is detected in real time；With the precharge
Circuit and the first controller of detection means connection, when the current voltage for detecting the dc-link capacitance meets default
During condition, the pre-charge circuit is controlled to disconnect；
The second control being connected with five level inverse conversion units of five level photovoltaic inverter and the detection means
Device, when when detecting the pre-charge circuit and disconnecting, the current voltage of the dc-link capacitance is not less than the first threshold values, control
Make five level photovoltaic inverter and be operated in three level active patterns, to reduce the current voltage of the dc-link capacitance,
And the current voltage of the dc-link capacitance after reduction is when reaching the second threshold values, five level photovoltaic inverter is controlled to exit
Enter normal grid-connected mode of operation after the three level actives pattern.
It is preferred that, in addition to：
The 3rd control being connected with five level inverse conversion units of five level photovoltaic inverter and the detection means
Device, when when detecting the pre-charge circuit and disconnecting, the current voltage of the dc-link capacitance is less than the first threshold values, control
Five level photovoltaic inverter enters normal grid-connected mode of operation.
It is preferred that, line precharge is entered to the dc-link capacitance of five level photovoltaic inverters by pre-charge circuit in power network
During, the detection means is additionally operable to detect line voltage peak value in real time, then the system also includes：
The first warning device being connected with the detection means, for being set when the line voltage peak value fluctuation range exceedes
When determining threshold value, the first warning message is exported；
Wherein, first warning message is specially indicator lamp flash signal, buzzer voice signal or includes alarm
The voice signal of content.
It is preferred that, the system also includes：
The second warning device being connected with the detection means is not small for the current voltage in the dc-link capacitance
When the first threshold values, the second warning message is exported；
Wherein, second warning message is specially indicator lamp flash signal, buzzer voice signal or includes alarm
The voice signal of content.
It is preferred that, first controller, the second controller and the 3rd controller are specially：Single-chip microcomputer, MCU
Or DSP.
As can be seen here, compared with prior art, it is pre-charged controlling party this application provides a kind of five level photovoltaic inverter
Method and system, because before the startup of five level photovoltaic inverters, power network can be inverse to the five level photovoltaic by pre-charge circuit
The dc-link capacitance for becoming device enters line precharge, therefore, in order to prevent the voltage of the dc-link capacitance from exceeding maximum protection electricity
Pressure, and cause five level photovoltaic inverters not start, the present invention by detecting the dc bus in real time in pre-charge process
The current voltage of electric capacity, is to disconnect the pre-charge circuit when it meets preparatory condition, now, if dc-link capacitance is current
When voltage is not less than the first threshold values, five level photovoltaic inverter is controlled to be operated in three level active patterns, to reduce the direct current
Bus capacitor voltage, and the current voltage of the dc-link capacitance after reduction reached after the second threshold values, controls the five level light
Volt inverter, which is exited after three level active patterns, enters normal grid-connected mode of operation, so as to solve in the prior art to straight
When flowing the disconnection of bus capacitor pre-charge circuit, because its voltage exceedes maximum protection voltage, and make five level photovoltaic inverters can not
It is normal to start, so as to influence the technical problem of grid-connected photovoltaic system reliability service.
Brief description of the drawings
In order to illustrate more clearly about the embodiment of the present invention or technical scheme of the prior art, below will be to embodiment or existing
There is the accompanying drawing used required in technology description to be briefly described, it should be apparent that, drawings in the following description are only this
The embodiment of invention, for those of ordinary skill in the art, on the premise of not paying creative work, can also basis
The accompanying drawing of offer obtains other accompanying drawings.
Fig. 1 is a kind of existing structural representation of the photovoltaic parallel in system based on five level photovoltaic inverters；
Fig. 2 is a kind of schematic flow sheet of five level photovoltaic inverters precharge control method of the present invention；
Fig. 3 is the schematic flow sheet of another five level photovoltaic inverters precharge control method of the present invention；
Fig. 4 is a kind of structural representation of five level photovoltaic inverters preliminary filling electric control system of the present invention.
Embodiment
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 clear, complete
Site preparation is described, it is clear that described embodiment is only a part of embodiment of the invention, rather than whole embodiments.It is based on
Embodiment in the present invention, it is every other that those of ordinary skill in the art are obtained under the premise of creative work is not made
Embodiment, belongs to the scope of protection of the invention.
This application provides a kind of five level photovoltaic inverters precharge control method and system, due in five level photovoltaics
Before inverter startup, power network can carry out preliminary filling by pre-charge circuit to the dc-link capacitance of five level photovoltaic inverter
Electricity, therefore, in order to prevent the dc-link capacitance voltage exceed maximum protection voltage, and cause five level photovoltaic inverters without
Method starts, the current voltage of the invention by detecting the dc-link capacitance in real time in pre-charge process, when its satisfaction is default
Condition is to disconnect the pre-charge circuit, now, if the current voltage of dc-link capacitance is not less than the first threshold values, and control should
Five level photovoltaic inverters are operated in three level active patterns, to reduce the dc-link capacitance voltage, and straight after reduction
The current voltage of stream bus capacitor is reached after the second threshold values, controls five level photovoltaic inverter to exit after three level active patterns
Into normal grid-connected mode of operation, so that at the end of solving dc-link capacitance being pre-charged in the prior art, because of it
Voltage exceedes maximum protection voltage, and five level photovoltaic inverters is not started normally, so as to influence parallel network power generation system
The technical problem of system reliability service.
Embodiment one：
A kind of schematic flow sheet of five level photovoltaic inverters precharge control method of the invention shown in reference picture 2,
In the present embodiment, this method specifically may comprise steps of：
Step S11：When power network passes through dc-link capacitance progress preliminary filling of the pre-charge circuit to five level photovoltaic inverters
When electric, the current voltage of the dc-link capacitance is detected in real time.
In the practical application of grid-connected photovoltaic system, in order to prevent power network from being rushed to photovoltaic DC-to-AC converter that will be grid-connected
Hit, generally all line precharge can be entered to the dc-link capacitance of the photovoltaic DC-to-AC converter before photovoltaic DC-to-AC converter is started.
Wherein, in order to grasp the situation of change of line voltage and DC bus-bar voltage in real time, in the present embodiment practical application
In, line voltage peak value and DC bus-bar voltage can in real time be detected.
Step S12：When the current voltage of the dc-link capacitance detected meets preparatory condition, the precharge is controlled
Circuit disconnects.
Wherein, preparatory condition can be line voltage peak value, then in the practical application of the present embodiment, when dc bus electricity
When appearance voltage reaches line voltage peak value, pre-charge circuit will be switched off.
Step S13：When detecting the pre-charge circuit and disconnecting, the current voltage of the dc-link capacitance is not less than
During the first threshold values, five level photovoltaic inverters of control are operated in three level active patterns, to reduce the current of dc-link capacitance
Voltage.
In power network carries out pre-charge process to dc-link capacitance, because line voltage is continually changing, thus,
When disconnecting pre-charge circuit, if line voltage peakedness ratio is larger, it will dc-link capacitance voltage is exceeded its maximum protection electricity
Pressure is the first threshold values, so as to influence the normal startup of five level photovoltaic inverters, based on this, the present embodiment passes through to line voltage
Peak value and dc-link capacitance voltage are detected in real time, when disconnecting pre-charge circuit, if line voltage peak value is larger, and direct current is female
When the current voltage of line capacitance is not less than the first threshold values, five level photovoltaic inverters are can control first in three level active pattern works
Make, so that the dc-link capacitance of five level photovoltaic inverters and five level inverse conversion units formation discharge loop, to reach drop
The purpose of low dc-link capacitance voltage.
Specifically, with reference to the structural representation of five level photovoltaic inverter illustrated in fig. 1, starting the five level photovoltaic
Before inverter, power network is that dc-link capacitance is that positive pole line capacitance C1 and negative busbar electric capacity C2 charges by pre-charge circuit,
When the dc-link capacitance voltage detected reaches line voltage peak value, and when disconnecting pre-charge circuit, if now dc bus
Capacitance voltage be not less than the first threshold values, then control the second positive level P2 switch module SP2, zero level N switch module SN0 with
And second negative level N2 switch module SN2 work, that is, control five level photovoltaic inverters to be operated in three level active patterns, this
When, positive pole line capacitance C1, negative busbar electric capacity C2, switching molding in three-phase photovoltaic grid-connected electricity generation system in five level photovoltaic inverters
Block SN2 switch modules SN0 and switch module SP2 will form loop.
, wherein it is desired to illustrate, five switches of five level inverse conversion units of five level photovoltaic inverters in the present invention
Module is specifically as follows IGBT, and (Insulated Gate Bipolar Transistor, insulated gate bipolar transistor etc. is partly led
Body switching device, the present invention is not especially limited to this.Optionally, when detecting, the fluctuation of line voltage peak value is larger to fluctuate model
When enclosing more than given threshold, system can directly export the first warning message, such as indicator lamp flash signal, buzzer voice signal or
Include voice signal of alarm content etc., now line voltage is unstable to inform staff, dc-link capacitance electricity
Pressure will be too high, influences the normal startup of five level photovoltaic inverters.It should be noted that output shape of the present invention to warning message
Formula is not especially limited.
As another embodiment of the present invention, after step S12 is performed, that is, when disconnecting pre-charge circuit, if now detecting
The current voltage of dc-link capacitance be less than the first threshold values, can directly control five level photovoltaic inverters to enter normal grid-connected work
Operation mode works.Wherein, the first threshold values can be the maximum protection voltage of dc-link capacitance, and the present invention is to its specific magnitude of voltage
It is not construed as limiting.
Step S14：When the current voltage for detecting the dc-link capacitance after reduction reaches the second threshold values, the electricity of control five
Flat photovoltaic DC-to-AC converter, which is exited after three level active patterns, enters normal grid-connected mode of operation.
Wherein, the 95% of its normal grid voltage peak value when the second threshold values can be power network normal work, but do not limit to
In this, it is necessary to which explanation, the first threshold values is more than the second threshold values
In the present embodiment, the loop formed in five level photovoltaic inverters under three level active patterns is electric to dc bus
Hold and carry out in discharge process, system can also detect the voltage of dc-link capacitance in real time, once it is determined that the voltage after electric discharge reaches
During Second Threshold, you can five level photovoltaic inverters of control exit three level active patterns, and start the five level photovoltaic inversion
Device controls five level photovoltaic inverters normally to start, it is necessary to which explanation, electric for five in normal grid-connected mode of operation
The detailed process that flat photovoltaic DC-to-AC converter normally starts is not especially limited.
Optionally, when it is determined that the current voltage of dc-link capacitance is not less than the first threshold values, system can export second
Warning message, such as indicator lamp flash signal, buzzer voice signal or the voice signal for including alarm content, the present invention
This is not especially limited.
As can be seen here, the embodiment of the present invention by when power network is pre-charged to dc-link capacitance, detecting the direct current in real time
The current voltage of bus capacitor, when it meets preparatory condition, disconnects pre-charge circuit, and the dc bus that ought now detect
When the current voltage of electric capacity is not less than the first threshold values, controls five level photovoltaic inverter to be operated in three level active patterns, make
Five level inverse conversion units and dc-link capacitance formation discharge loop are obtained, so that dc-link capacitance voltage is reduced, work as inspection
When the current voltage of dc-link capacitance after the reduction measured reaches the second threshold values, the five-electrical level inverter is controlled to exit three electricity
Enter normal grid-connected mode of operation after flat mode of operation, broken so as to solve prior art to dc-link capacitance
During precharge, five level photovoltaic inverters are made not start normally because its voltage exceedes maximum protection voltage, so as to influence light
The technical problem of photovoltaic grid-connected system reliability service.
Embodiment two：
The schematic flow sheet of another five level photovoltaic inverters precharge control method of the invention shown in reference picture 4,
Wherein, the topological diagram of five level photovoltaic inverters can refer to Fig. 1, and the present embodiment will not be described in detail herein, then the control method can be wrapped
Include following steps：
Step S21：When power network passes through dc-link capacitance progress preliminary filling of the pre-charge circuit to five level photovoltaic inverters
When electric, the current voltage and line voltage peak value of the dc-link capacitance are detected in real time.
Step S22：When the current voltage of the dc-link capacitance detected is equal to the line voltage peak value, preliminary filling is disconnected
Circuit.
Step S23：Judge whether the current voltage of dc-link capacitance detected when pre-charge circuit disconnects is less than the
One threshold values, if it is not, then entering step S24, if so, then performing step S26.
Step S24：Five level photovoltaic inverter is controlled to be operated in three level active patterns, it is female to reduce the direct current
The current voltage of line capacitance.
Step S25：When the current voltage for detecting the dc-link capacitance after reduction reaches the second threshold values, the electricity of control five
Flat photovoltaic DC-to-AC converter, which is exited after three level active patterns, enters normal grid-connected mode of operation.
Step S26：Five level photovoltaic inverters are controlled to enter normal grid-connected mode of operation.
Optionally, compare operation for above-mentioned, different warning messages can be exported according to different comparative results, are such as indicated
Lamp flash signal, buzzer voice signal or the voice signal for including alarm content, so that staff can be intuitively and fast
The current operating state of five level photovoltaic inverters is determined fastly.
As can be seen here, the embodiment of the present invention is by the way that in power network, in dc-link capacitance pre-charge process, detection in real time should
The current voltage of dc-link capacitance, when it reaches line voltage peak value, disconnects pre-charge circuit, and detecting now
When dc-link capacitance voltage is not less than the first threshold values, five level photovoltaic inverter is controlled to be operated in three level active patterns,
So that five level inverse conversion units and dc-link capacitance formation discharge loop, to reduce the current voltage of dc-link capacitance, when
When the current voltage of dc-link capacitance after reduction reaches the second threshold values, five level photovoltaic inverters of control exit three level works
Normal grid-connected mode of operation is reentered after operation mode, dc-link capacitance is pre-charged in the prior art so as to solve
At the end of, cause five level photovoltaic inverters not start normally because its voltage exceedes maximum protection voltage, so as to influence light
The technical problem of photovoltaic grid-connected system reliability service.
Embodiment three：
A kind of structural representation of five level photovoltaic inverters preliminary filling electric control system of the invention shown in reference picture 4, its
In, five level photovoltaic inverter can include the first DC/DC circuits, the 2nd DC/DC circuits, dc-link capacitance and five level
Inversion unit, its specific attachment structure and its annexation with other devices in grid-connected photovoltaic system can refer to figure
1, the present embodiment is no longer repeated herein, then the preliminary filling electric control system can specifically include：The controller of detection means 31 and first
32 and second controller 33, wherein：
Detection means 31 is connected with the dc-link capacitance of five level photovoltaic inverters, for when power network is by being pre-charged electricity
When line precharge is entered in road to dc-link capacitance, the current voltage of dc-link capacitance is detected in real time.
Wherein, in the practical application of the present embodiment, the detection means 31 is specifically as follows voltage sensor or voltage is adopted
Sample circuit etc., the present invention is not especially limited to this.
In addition, as illustrated, because the dc-link capacitance is divided into positive bus capacitor C1 and negative sense bus capacitor C2, because
And, the detection means 31 specifically can include first detection circuit and second detection circuit, for respectively with positive bus capacitor
C1 and negative sense bus capacitor C2 are connected one to one, and positive bus capacitor C1 the first current voltage, and negative sense are detected respectively
Bus capacitor C2 the second current voltage.
First controller 32 is connected with the five level inverse conversion units and the detection means 31 of five level photovoltaic inverters, is used
In when the current voltage for detecting the dc-link capacitance meets preparatory condition, the pre-charge circuit is controlled to disconnect.
Wherein, the preparatory condition is that dc-link capacitance voltage is equal to line voltage peak value.
Second controller 33 is connected with the five level inverse conversion units and detection means 31 of five level photovoltaic inverters, is used for
When the current voltage for detecting the dc-link capacitance when pre-charge circuit disconnects is not less than the first threshold values, institute is controlled
State five level photovoltaic inverters and be operated in three level active patterns, to reduce the current voltage of the dc-link capacitance, and
When the current voltage of dc-link capacitance after reduction reaches the second threshold values, control level photovoltaic inverter exits three level
Enter normal grid-connected mode of operation after mode of operation.
In actual applications, when the detection means 31 includes the first detection circuit and the second detection circuit, respectively to forward direction
When bus capacitor C1 and negative sense bus capacitor C2 are detected, as long as determining positive bus capacitor C1 when pre-charge circuit disconnects
The first current voltage and negative sense bus capacitor C2 the second current voltage sum be more than first threshold, you can enter three level works
Operation mode, the loop formed by dc-link capacitance and five level inverse conversion units is automatically female to positive the bus capacitor C1 and negative sense
Line capacitance C2 discharges, so as to reach the purpose of reduction dc-link capacitance voltage.
Wherein, the first controller 32 and second controller 33 are specifically as follows MCU (Micro Control Unit, micro-control
Unit processed), single-chip microcomputer or DSP (Digtal Signal Process, Digital Signal Processing) etc., the present invention does not make to this
It is specific to limit.
Optionally, five level photovoltaic inverters preliminary filling electric control system provided by the present invention can also include：
The 3rd control being connected with the five level inverse conversion units and the detection means 31 of five level photovoltaic inverter
Device processed, during for being less than the first threshold values in the current voltage for detecting dc-link capacitance when pre-charge circuit disconnects, control
Make five level photovoltaic inverter and enter normal grid-connected mode of operation.
In addition, the control system can also include the alarm module being connected with second controller 33, then work as second controller
When the current voltage of dc-link capacitance is more than first threshold when 32 determination pre-charge circuits disconnect, sent to the alarm module
3rd trigger signal, makes it export warning message.
Wherein, the alarm module is specifically as follows indicator lamp, buzzer or voice module etc., and the present invention does not make to have to this
Body is limited.
In summary, in embodiments of the present invention, it is real-time by detection means when power network is pre-charged to dc-link capacitance
The current voltage of dc-link capacitance is detected, when it meets preparatory condition, the pre-charge circuit is disconnected by the first controller, and
When detection means detects pre-charge circuit and disconnected, when dc-link capacitance voltage is not less than the first threshold values, by the second control
Device controls five level photovoltaic inverter to be operated in three level active patterns so that five level inverse conversion units and dc-link capacitance
Discharge loop is formed, and when the current voltage that detection means detects the dc-link capacitance after decompression reaches Second Threshold,
Second controller five level photovoltaic inverters of control, which are exited after three level active patterns, enters normal grid-connected mode of operation, from
And solve in the prior art because dc-link capacitance voltage is more than its maximum protection voltage, and cause five level photovoltaic inverters
Can not normally it start, so as to influence the technical problem of grid-connected photovoltaic system reliability service.
It should be noted that in said system embodiment of the present invention, in addition to the module of above-mentioned record, can also include
Display, memory and connection member for connecting each device etc., the present invention no longer illustrates one by one herein, so long as not
Those skilled in the art pay creative work determination, belong to the scope of the present invention.
In addition, the explanation that the various embodiments described above are carried out only for any phase of grid-connected photovoltaic system, other two-phases
Precharge control method is similar with system, and this is no longer described in detail the present invention.Moreover, in the various embodiments described above, such as first,
Second or the like relational terms are used merely to make a distinction an operation or entity with another operation or entity, and differ
Provisioning request implies between these entities or operation there is any this actual relation or order.
The embodiment of each in this specification is described by the way of progressive, and what each embodiment was stressed is and other
Between the difference of embodiment, each embodiment identical similar portion mutually referring to.For system disclosed in embodiment
For, because it is corresponding with method disclosed in embodiment, so description is fairly simple, related part is referring to method part illustration
.
The foregoing description of the disclosed embodiments, enables professional and technical personnel in the field to realize or using the present invention.
A variety of modifications to these embodiments will be apparent for those skilled in the art, as defined herein
General Principle can be realized in other embodiments without departing from the spirit or scope of the present invention.Therefore, it is of the invention
The embodiments shown herein is not intended to be limited to, and is to fit to and principles disclosed herein and features of novelty phase one
The most wide scope caused.
Claims (8)
1. a kind of five level photovoltaic inverters precharge control method, it is characterised in that methods described includes：
When power network enters line precharge by pre-charge circuit to the dc-link capacitance of five level photovoltaic inverters, detection in real time
The current voltage of the dc-link capacitance；
When the current voltage of the dc-link capacitance meets preparatory condition, the pre-charge circuit is controlled to disconnect；
When detecting the pre-charge circuit and disconnecting, the current voltage of the dc-link capacitance is not less than the first threshold values, control
Make five level photovoltaic inverter and be operated in three level active patterns, to reduce the current voltage of the dc-link capacitance；
When the current voltage for detecting the dc-link capacitance after reduction reaches the second threshold values, control the five level photovoltaic inverse
Become device to exit after the three level actives pattern into the normal grid-connected mode of operation of five level；
When detecting the pre-charge circuit and disconnecting, the current voltage of the dc-link capacitance is less than the first threshold values, control
Five level photovoltaic inverter enters normal grid-connected mode of operation.
2. according to the method described in claim 1, it is characterised in that in power network by pre-charge circuit to five level photovoltaic inversions
The dc-link capacitance of device is carried out in pre-charge process, in addition to：
Line voltage peak value is detected in real time；
When the line voltage peak value fluctuation range exceedes given threshold, the first warning message is exported；
Wherein, first warning message is specially indicator lamp flash signal, buzzer voice signal or includes alarm content
Voice signal.
3. according to the method described in claim 1, it is characterised in that when the current voltage of the dc-link capacitance is not less than the
During one threshold values, in addition to：Export the second warning message；
Wherein, second warning message is specially indicator lamp flash signal, buzzer voice signal or includes alarm content
Voice signal.
4. the method according to claim any one of 1-3, it is characterised in that control five level photovoltaic inverter
Being operated in three level active patterns is specially：
Control is negative with the second positive level in five level inverse conversion units of five level photovoltaic inverter, zero level and second
The one-to-one switch module work of level, so that the dc-link capacitance and second positive level, second negative electricity
The one-to-one switch module formation discharge loop of flat and zero level.
5. a kind of five level photovoltaic inverters preliminary filling electric control system, it is characterised in that including：
The detection means being connected with the dc-link capacitance of five level photovoltaic inverters, when power network by pre-charge circuit to described
When dc-link capacitance enters line precharge, the current voltage of the dc-link capacitance is detected in real time；With the pre-charge circuit
The first controller connected with the detection means, when the current voltage for detecting the dc-link capacitance meets preparatory condition
When, control the pre-charge circuit to disconnect；
The second controller being connected with five level inverse conversion units of five level photovoltaic inverter and the detection means, when
When the current voltage for detecting the dc-link capacitance when pre-charge circuit disconnects is not less than the first threshold values, control is described
Five level photovoltaic inverters are operated in three level active patterns, to reduce the current voltage of the dc-link capacitance, and in drop
When the current voltage of dc-link capacitance after low reaches the second threshold values, five level photovoltaic inverter is controlled to exit described three
Enter the normal grid-connected mode of operation of five level after level active pattern；With five level of five level photovoltaic inverter
Inversion unit and the 3rd controller of detection means connection, the direct current when detecting the pre-charge circuit and disconnecting
When the current voltage of bus capacitor is less than the first threshold values, five level photovoltaic inverter is controlled to enter normal grid-connected mode of operation
Work.
6. system according to claim 5, it is characterised in that in power network by pre-charge circuit to five level photovoltaic inversions
The dc-link capacitance of device is carried out in pre-charge process, and the detection means is additionally operable to detect line voltage peak value in real time, then institute
Stating system also includes：
The first warning device being connected with the detection means, for exceeding setting threshold when the line voltage peak value fluctuation range
During value, the first warning message is exported；
Wherein, first warning message is specially indicator lamp flash signal, buzzer voice signal or includes alarm content
Voice signal.
7. system according to claim 5, it is characterised in that the system also includes：
The second warning device being connected with the detection means, for the current voltage in the dc-link capacitance not less than the
During one threshold values, the second warning message is exported；
Wherein, second warning message is specially indicator lamp flash signal, buzzer voice signal or includes alarm content
Voice signal.
8. the system according to claim 6 or 7, it is characterised in that first controller, the second controller and institute
Stating the 3rd controller is specially：MCU.
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| US11831238B2 (en) | 2020-02-21 | 2023-11-28 | Delta Electronics, Inc. | Power conversion system |
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| CN117674253A (en) * | 2019-08-28 | 2024-03-08 | 华为数字能源技术有限公司 | Inverter, starting device, method and system of photovoltaic grid-connected power generation system |
| CN110994968B (en) * | 2019-11-22 | 2021-06-01 | 华为技术有限公司 | Pre-charging circuit, inverter and power generation system |
| CN113078815B (en) | 2020-01-03 | 2022-04-15 | 台达电子工业股份有限公司 | Power supply conversion system |
| WO2024092411A1 (en) * | 2022-10-31 | 2024-05-10 | 宁德时代未来能源(上海)研究院有限公司 | Grid connection control method, apparatus, and system for energy storage apparatus, and storage medium |
| CN117200568B (en) * | 2023-11-06 | 2024-02-27 | 广州奥鹏能源科技有限公司 | Bidirectional inverter soft start system for energy storage power supply and control method thereof |
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| KR100993108B1 (en) * | 2008-05-30 | 2010-11-08 | 군산대학교산학협력단 | A grid-interactive photovoltaic generation system with power quality control and energy saving |
| DE102009012928A1 (en) * | 2009-03-12 | 2010-09-16 | Kostal Industrie Elektrik Gmbh | Energy conversion system |
| DE102010060633B3 (en) * | 2010-11-17 | 2012-04-26 | Sma Solar Technology Ag | Method for connecting a photovoltaic system to a power supply network and photovoltaic system for carrying out the method |
| CN102624022A (en) * | 2011-01-30 | 2012-08-01 | 上海康威特吉能源技术有限公司 | Photovoltaic grid-connected power generation system and direct current bus voltage control method thereof |
| DE102011121197B4 (en) * | 2011-12-16 | 2013-08-22 | Sma Solar Technology Ag | Procedure for commissioning an inverter and inverter |
| CN202949375U (en) * | 2012-10-17 | 2013-05-22 | 阳光电源股份有限公司 | Five-level inversion unit and five-level inverter |
| CN102916603A (en) * | 2012-10-26 | 2013-02-06 | 哈尔滨东方报警设备开发有限公司 | Single-phase unsymmetrical multi-level inverter with pre-charging circuit and charging method of single-phase unsymmetrical multi-level inverter |
| CN103490446B (en) * | 2013-09-24 | 2015-06-03 | 许继集团有限公司 | Operational control method for photovoltaic inverter |
| CN104038088B (en) * | 2014-06-30 | 2017-02-15 | 阳光电源股份有限公司 | Method and device for controlling photovoltaic inverter circuit |
| CN104158218B (en) * | 2014-08-27 | 2017-03-01 | 阳光电源股份有限公司 | A kind of photovoltaic DC-to-AC converter starts control method, system and photovoltaic generating system |
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