CN104242353A - Photovoltaic grid-connected system as well as start control method and start control device - Google Patents
Photovoltaic grid-connected system as well as start control method and start control device Download PDFInfo
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- CN104242353A CN104242353A CN201410553239.1A CN201410553239A CN104242353A CN 104242353 A CN104242353 A CN 104242353A CN 201410553239 A CN201410553239 A CN 201410553239A CN 104242353 A CN104242353 A CN 104242353A
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
- Y02E10/56—Power conversion systems, e.g. maximum power point trackers
Abstract
The invention discloses a photovoltaic grid-connected system as well as a start control method and a start control device. The start control method comprises the steps of locating photovoltaic inverters satisfying a start condition in the photovoltaic grid-connected system, controlling all or partial photovoltaic inverters satisfying the start condition to perform exciting soft start on a boosting transformer by taking a middle-high grid voltage as an expected output exciting voltage of the boosting transformer in the photovoltaic grid-connected system, controlling the photovoltaic inverters not taking part in exciting soft start in the photovoltaic grid-connected system to go in a standby locking state, obtaining the actual output exciting voltage of the boosting transformer, and when detecting that the difference value between the exciting voltage and the middle-high grid voltage is within an error allowance range, connecting the boosting transformer with the middle-high grid and deactivating the standby locking state of the photovoltaic inverters not taking part in exciting soft start to prevent the generation of an impact current at the moment when the boosting transformer is connected with the middle-high grid, thereby protecting equipment against damage.
Description
Technical field
The present invention relates to technical field of photovoltaic power generation, more particularly, relate to photovoltaic parallel in system and start control method and start control device.
Background technology
Photovoltaic energy is fed to low voltage electric network by step-up transformer by photovoltaic parallel in system.When unglazed photograph at night, photovoltaic parallel in system enters holding state, but because the high-pressure side of step-up transformer is connected with low voltage electric network all the time, therefore no-load loss can be produced at photovoltaic parallel in system step-up transformer of standby period, according to statistics, the electricity of the 315V/10kV step-up transformer 1 year no-load loss of 1kVA is up to 7300kWh.
For solving this problem, prior art proposes mesohigh interconnection technology, that is: using the part of step-up transformer as photovoltaic parallel in system; The connection of the complete standby rear cut-out step-up transformer of the photovoltaic DC-to-AC converter in photovoltaic parallel in system and mesohigh electrical network, thus solve the large problem of step-up transformer no-load loss; Step-up transformer and electrical network is connected again, to realize being incorporated into the power networks of photovoltaic parallel in system when described photovoltaic DC-to-AC converter needs to recover grid-connected.But, if directly adhesive connects the switch of mesohigh electrical network and step-up transformer, in connection instantaneously, have impulse current and flow through step-up transformer and switch causes device damage.
Summary of the invention
In view of this, the invention provides photovoltaic parallel in system and start control method and start control device, produce impulse current instantaneously to avoid step-up transformer and mesohigh electrical network to connect, thus proterctive equipment not being damaged.
A startup control method for photovoltaic parallel in system, comprising:
The photovoltaic DC-to-AC converter meeting entry condition is searched in photovoltaic parallel in system;
Exciting voltage using mesohigh line voltage as the step-up transformer desired output in described photovoltaic parallel in system, controls all or part of photovoltaic DC-to-AC converter meeting entry condition and carries out excitation delay startup to described step-up transformer; And the photovoltaic DC-to-AC converter controlling to have neither part nor lot in described photovoltaic parallel in system excitation delay startup enters standby lock-out state;
Obtain the exciting voltage of the actual output of described step-up transformer;
When detecting that the difference of described exciting voltage and mesohigh line voltage drops in error allowed band, connect described step-up transformer and mesohigh electrical network, and have neither part nor lot in the standby lock-out state of the photovoltaic DC-to-AC converter of excitation delay startup described in removing.
Wherein, all or part of photovoltaic DC-to-AC converter meeting entry condition of described control carries out excitation delay startup to described step-up transformer, comprising:
Control a photovoltaic DC-to-AC converter meeting entry condition and independently excitation delay startup is carried out to described step-up transformer.
Wherein, all or part of photovoltaic DC-to-AC converter meeting entry condition of described control carries out excitation delay startup to described step-up transformer, comprising:
Control at least two photovoltaic DC-to-AC converters meeting entry condition and synchronously excitation delay startup is carried out to described step-up transformer.
Alternatively, after the exciting voltage of the actual output of the described step-up transformer of described acquisition, also comprise:
If do not detect at the appointed time, described difference drops in described error allowed band, then return the step performing and search the photovoltaic DC-to-AC converter meeting entry condition in photovoltaic parallel in system.
A startup control device for photovoltaic parallel in system, comprising:
Search unit, for searching the photovoltaic DC-to-AC converter meeting entry condition in photovoltaic parallel in system;
Start unit, for the exciting voltage using mesohigh line voltage as the step-up transformer desired output in described photovoltaic parallel in system, controls all or part of photovoltaic DC-to-AC converter meeting entry condition and carries out excitation delay startup to described step-up transformer; And the photovoltaic DC-to-AC converter controlling to have neither part nor lot in described photovoltaic parallel in system excitation delay startup enters standby lock-out state;
Acquiring unit, for obtaining the exciting voltage of the actual output of described step-up transformer;
First processing unit, for when detecting that the difference of described exciting voltage and mesohigh line voltage drops in error allowed band, connect described step-up transformer and mesohigh electrical network, and have neither part nor lot in the standby lock-out state of the photovoltaic DC-to-AC converter of excitation delay startup described in removing.
Wherein, described start unit comprises interlocking start unit; Described interlocking start unit is used for the exciting voltage using mesohigh line voltage as the step-up transformer desired output in described photovoltaic parallel in system, control a photovoltaic DC-to-AC converter meeting entry condition and independently excitation delay startup is carried out to described step-up transformer, and the photovoltaic DC-to-AC converter controlling to have neither part nor lot in described photovoltaic parallel in system excitation delay startup enters standby lock-out state.
Wherein, described start unit comprises synchronous averaging unit; Described synchronous averaging unit is used for the exciting voltage using mesohigh line voltage as the step-up transformer desired output in described photovoltaic parallel in system, control at least two photovoltaic DC-to-AC converters meeting entry condition and synchronously excitation delay startup is carried out to described step-up transformer, and the photovoltaic DC-to-AC converter controlling to have neither part nor lot in described photovoltaic parallel in system excitation delay startup enters standby lock-out state.
Alternatively, described startup control device also comprises:
Second processing unit, if for not detecting that described difference drops in described error allowed band at the appointed time, then searches unit described in triggering.
A kind of photovoltaic parallel in system, comprise photovoltaic DC-to-AC converter, step-up transformer and gate-controlled switch, described in the low pressure side joint of described step-up transformer, photovoltaic DC-to-AC converter, high-pressure side connect mesohigh electrical network through described gate-controlled switch, in addition, also comprise:
For the sample circuit of the high side voltage of described step-up transformer of sampling;
And the Centralized Controller be connected with described sample circuit with described photovoltaic DC-to-AC converter, described gate-controlled switch respectively, for searching the photovoltaic DC-to-AC converter meeting entry condition in photovoltaic parallel in system; Exciting voltage using mesohigh line voltage as the step-up transformer desired output in described photovoltaic parallel in system, controls all or part of photovoltaic DC-to-AC converter meeting entry condition and carries out excitation delay startup to described step-up transformer; And the photovoltaic DC-to-AC converter controlling to have neither part nor lot in described photovoltaic parallel in system excitation delay startup enters standby lock-out state; Obtain the exciting voltage of the actual output of described step-up transformer; When detecting that the difference of described exciting voltage and mesohigh line voltage drops in error allowed band, connect described step-up transformer and mesohigh electrical network, and have neither part nor lot in the standby lock-out state of the photovoltaic DC-to-AC converter of excitation delay startup described in removing.
A kind of photovoltaic parallel in system, comprise photovoltaic DC-to-AC converter, step-up transformer and gate-controlled switch, described in the low pressure side joint of this step-up transformer, photovoltaic DC-to-AC converter, high-pressure side connect mesohigh electrical network through described gate-controlled switch, in addition, also comprise:
For the sample circuit of the high side voltage of described step-up transformer of sampling;
Each photovoltaic DC-to-AC converter described is connected with each other by communication port, and is connected with described gate-controlled switch with described sample circuit respectively, for searching the photovoltaic DC-to-AC converter meeting entry condition in photovoltaic parallel in system; Exciting voltage using mesohigh line voltage as the step-up transformer desired output in described photovoltaic parallel in system, controls all or part of photovoltaic DC-to-AC converter meeting entry condition and carries out excitation delay startup to described step-up transformer; And the photovoltaic DC-to-AC converter controlling to have neither part nor lot in described photovoltaic parallel in system excitation delay startup enters standby lock-out state; Obtain the exciting voltage of the actual output of described step-up transformer; When detecting that the difference of described exciting voltage and mesohigh line voltage drops in error allowed band, connect described step-up transformer and mesohigh electrical network, and have neither part nor lot in the standby lock-out state of the photovoltaic DC-to-AC converter of excitation delay startup described in removing.
As can be seen from above-mentioned technical scheme, the present invention is before connection step-up transformer and mesohigh electrical network, first control all or part of photovoltaic DC-to-AC converter meeting entry condition and excitation delay startup is carried out to step-up transformer, and standby locking is carried out to all the other photovoltaic DC-to-AC converters, until the exciting voltage of step-up transformer and mesohigh line voltage basically identical time just connect step-up transformer and mesohigh electrical network, remove standby locking; Compared to prior art, the present invention, owing to being connect step-up transformer and mesohigh electrical network under zero pressure difference, can not producing impulse current, therefore can not be damaged by proterctive equipment.
Accompanying drawing explanation
In order to be illustrated more clearly in the embodiment of the present invention or technical scheme of the prior art, be briefly described to the accompanying drawing used required in embodiment or description of the prior art below, apparently, accompanying drawing in the following describes is only embodiments of the invention, for those of ordinary skill in the art, under the prerequisite not paying creative work, other accompanying drawing can also be obtained according to the accompanying drawing provided.
The startup control method flow chart of Fig. 1 a kind of photovoltaic parallel in system disclosed in the embodiment of the present invention;
Fig. 2 is a kind of photovoltaic parallel in system structural representation disclosed in the embodiment of the present invention;
The startup control device structural representation of Fig. 3 a kind of photovoltaic parallel in system disclosed in the embodiment of the present invention.
Embodiment
Below in conjunction with the accompanying drawing in the embodiment of the present invention, be clearly and completely described the technical scheme in the embodiment of the present invention, obviously, described embodiment is only the present invention's part embodiment, instead of whole embodiments.Based on the embodiment in the present invention, those of ordinary skill in the art, not making the every other embodiment obtained under creative work prerequisite, belong to the scope of protection of the invention.
See Fig. 1, the embodiment of the invention discloses a kind of startup control method of photovoltaic parallel in system, produce impulse current instantaneously to avoid step-up transformer and mesohigh electrical network to connect, thus proterctive equipment be not damaged, and comprising:
Step 101: search the photovoltaic DC-to-AC converter meeting entry condition in photovoltaic parallel in system;
Step 102: the exciting voltage using mesohigh line voltage as the step-up transformer desired output in described photovoltaic parallel in system, controls all or part of photovoltaic DC-to-AC converter meeting entry condition and carries out excitation delay startup to described step-up transformer; And the photovoltaic DC-to-AC converter controlling to have neither part nor lot in described photovoltaic parallel in system excitation delay startup enters standby lock-out state;
Step 103: the exciting voltage obtaining the actual output of described step-up transformer;
Step 104: judge whether the difference of described exciting voltage and mesohigh line voltage drops in error allowed band, if so, enters step 105; Otherwise, return step 103.
Step 105: connect described step-up transformer and mesohigh electrical network, and the standby lock-out state having neither part nor lot in the photovoltaic DC-to-AC converter of excitation delay startup described in removing.
The present embodiment is before connection step-up transformer and mesohigh electrical network, first control all or part of photovoltaic DC-to-AC converter meeting entry condition and excitation delay startup is carried out to step-up transformer, and standby locking is carried out to all the other photovoltaic DC-to-AC converters, until the exciting voltage of step-up transformer and mesohigh line voltage basically identical time just connect step-up transformer and mesohigh electrical network, remove standby locking; Compared to prior art, the present embodiment, owing to being connect step-up transformer and mesohigh electrical network under zero pressure difference, can not producing impulse current, therefore can not be damaged by proterctive equipment.
In order to the technical scheme described in clearer description the present embodiment, below using the photovoltaic parallel in system shown in Fig. 2 as application, step 101 ~ step 105 is described in detail.
Photovoltaic parallel in system shown in Fig. 2 comprises: photovoltaic DC-to-AC converter #1 ~ #N, gate-controlled switch (as contactor K), and low pressure side joint photovoltaic DC-to-AC converter #1 ~ #N, high-pressure side meet the step-up transformer T (can be two division or two winding transformer) of mesohigh electrical network through contactor K.When unglazed photograph at night, photovoltaic DC-to-AC converter #1 ~ #N enters holding state automatically, and immediately, photovoltaic parallel in system control contactor K turns off, to solve the large problem of step-up transformer T no-load loss.
1) about step 101
When photovoltaic DC-to-AC converter needs to recover grid-connected, first the present embodiment searches the photovoltaic DC-to-AC converter that photovoltaic parallel in system meets entry condition, namely, for the photovoltaic parallel in system shown in Fig. 2, if the input voltage of photovoltaic DC-to-AC converter #1, #2 and #3 is all greater than respective starting resistor, then photovoltaic DC-to-AC converter #1, #2 and #3 is 3 photovoltaic DC-to-AC converters meeting entry condition found in photovoltaic parallel in system.
2) about step 102
The exciting voltage of the present embodiment using mesohigh line voltage as step-up transformer T desired output, selects any platform to carry out excitation delay startup to step-up transformer T from the photovoltaic DC-to-AC converter meeting entry condition.Concrete, those skilled in the art only can control a photovoltaic DC-to-AC converter meeting entry condition and carry out excitation delay startup to step-up transformer T independently, also can control simultaneously multiple stage meet the photovoltaic DC-to-AC converter of entry condition synchronous excitation delay startup (described multiple stage photovoltaic DC-to-AC converter will synchronous operation all the time in the process of step-up transformer T being carried out to excitation delay startup, to avoid conflict) is carried out to step-up transformer T.
In addition, during this period, also need the photovoltaic DC-to-AC converter controlling to have neither part nor lot in excitation delay startup in described photovoltaic parallel in system all to enter standby lock-out state, to avoid the photovoltaic DC-to-AC converter having neither part nor lot in excitation delay startup, interference is caused to above-mentioned excitation delay startup process.For entering the photovoltaic DC-to-AC converter of standby lock-out state, when only having it to meet entry condition and receive the instruction removing standby lock-out state, could startup optimization.
Illustrate, the photovoltaic DC-to-AC converter supposing to meet in Fig. 2 entry condition is #1, #2 and #3, so: staff can select photovoltaic DC-to-AC converter #1 to carry out excitation delay startup to step-up transformer T independently, and control photovoltaic DC-to-AC converter #2 ~ #N and enter standby lock-out state; Or, #1 ~ #2 also can be selected synchronously to carry out excitation delay startup to step-up transformer T, and control #3 ~ #N enters standby lock-out state; Or, also can all select #1 ~ #3 synchronously to carry out excitation delay startup to step-up transformer K, and control #4 ~ #N enters standby lock-out state.Certainly, when the photovoltaic DC-to-AC converter meeting entry condition in Fig. 2 is only #1, so directly control #1 carries out excitation delay startup to step-up transformer T, and control #2 ~ #N enters standby lock-out state.
3) step 103 ~ step 105
The present embodiment judges whether the exciting voltage (i.e. the high side voltage of step-up transformer T) of the actual output of step-up transformer T and the difference of mesohigh line voltage drop in error allowed band repeatedly, until the high side voltage of step-up transformer T is equal with mesohigh line voltage or approximately equal time just adhesive contactor K, owing to substantially there is not voltage difference between step-up transformer T and mesohigh electrical network, therefore the moment of adhesive contactor K, impulse current can not be produced step-up transformer T and contactor K is suffered damage.Afterwards, the standby lock-out state of all the other photovoltaic DC-to-AC converters can be removed, make it to participate in directly and be incorporated into the power networks.
Wherein, determine that the exciting voltage of the actual output of step-up transformer T and the difference of mesohigh line voltage drop on the condition in error allowed band, Ke Yiwei:
In formula, Rms (U
ab), Rms (U
bc) be respectively step-up transformer T on high-tension side AB, BC phases line voltage amplitude; Rms (U
aB), Rms (U
bC) be respectively AB, BC phases line voltage amplitude of mesohigh electrical network; Δ U is the amplitude error that the high side voltage of step-up transformer T and mesohigh line voltage allow; The high side voltage phase angle that θ ' is step-up transformer T; θ is mesohigh grid voltage phase-angle; Δ θ is the phase angle error that the high side voltage of step-up transformer T and mesohigh line voltage allow.
Visible, the photovoltaic parallel in system of application the present embodiment utilizes contactor K to control the switching of mesohigh electrical network, when photovoltaic DC-to-AC converter enters holding state completely, just disconnect contactor K, and when photovoltaic DC-to-AC converter needs to recover grid-connected, just closed contactor K under zero pressure difference, realizes system safety grid-connected, both solved the problem that step-up transformer T no-load loss is large, and turn avoid step-up transformer and mesohigh electrical network and connect and produce impulse current instantaneously and cause device damage.
In addition, as preferably, after step 103, also comprise: if the exciting voltage of the actual output of step-up transformer T and the difference of mesohigh line voltage do not drop in described error allowed band at the appointed time, then return step 101 (Fig. 1 is not shown), slowly cannot finish the work because of fault or other reasons, incur loss through delay to avoid the photovoltaic DC-to-AC converter participating in the work of excitation delay startup grid-connected time of photovoltaic parallel in system.
See Fig. 3, the embodiment of the invention also discloses a kind of startup control device of photovoltaic parallel in system, comprising:
Search unit 301, for searching the photovoltaic DC-to-AC converter meeting entry condition in photovoltaic parallel in system;
Start unit 302, for the exciting voltage using mesohigh line voltage as the step-up transformer desired output in described photovoltaic parallel in system, controls all or part of photovoltaic DC-to-AC converter meeting entry condition and carries out excitation delay startup to described step-up transformer; And the photovoltaic DC-to-AC converter controlling to have neither part nor lot in described photovoltaic parallel in system excitation delay startup enters standby lock-out state;
Acquiring unit 303, for obtaining the exciting voltage of the actual output of described step-up transformer;
First processing unit 304, for when detecting that the difference of described exciting voltage and mesohigh line voltage drops in error allowed band, connect described step-up transformer and mesohigh electrical network, and have neither part nor lot in the standby lock-out state of the photovoltaic DC-to-AC converter of excitation delay startup described in removing.
Wherein, start unit 302 comprises interlocking start unit, described interlocking start unit is used for the exciting voltage using mesohigh line voltage as the step-up transformer desired output in described photovoltaic parallel in system, control a photovoltaic DC-to-AC converter meeting entry condition and independently excitation delay startup is carried out to described step-up transformer, and the photovoltaic DC-to-AC converter controlling to have neither part nor lot in described photovoltaic parallel in system excitation delay startup enters standby lock-out state.
Or, start unit 302 comprises synchronous averaging unit, described synchronous averaging unit is used for the exciting voltage using mesohigh line voltage as the step-up transformer desired output in described photovoltaic parallel in system, control at least two photovoltaic DC-to-AC converters meeting entry condition and synchronously excitation delay startup is carried out to described step-up transformer, and the photovoltaic DC-to-AC converter controlling to have neither part nor lot in described photovoltaic parallel in system excitation delay startup enters standby lock-out state.
As preferably, still see Fig. 3, described startup control device also comprises: the second processing unit 305, if for not detecting that described difference drops in described error allowed band at the appointed time, triggering lookup unit 301.
In addition, the embodiment of the invention also discloses a kind of photovoltaic parallel in system, comprise photovoltaic DC-to-AC converter, step-up transformer, gate-controlled switch, sample circuit for the high side voltage of described step-up transformer of sampling, and the Centralized Controller be connected with described sample circuit with described photovoltaic DC-to-AC converter, described gate-controlled switch respectively, wherein:
Described in the low pressure side joint of described step-up transformer, photovoltaic DC-to-AC converter, high-pressure side connect mesohigh electrical network through described gate-controlled switch;
Described Centralized Controller is used in photovoltaic parallel in system, search the photovoltaic DC-to-AC converter meeting entry condition; Exciting voltage using mesohigh line voltage as the step-up transformer desired output in described photovoltaic parallel in system, controls all or part of photovoltaic DC-to-AC converter meeting entry condition and carries out excitation delay startup to described step-up transformer; And the photovoltaic DC-to-AC converter controlling to have neither part nor lot in described photovoltaic parallel in system excitation delay startup enters standby lock-out state; Obtain the exciting voltage of the actual output of described step-up transformer; When detecting that the difference of described exciting voltage and mesohigh line voltage drops in error allowed band, connect described step-up transformer and mesohigh electrical network, and have neither part nor lot in the standby lock-out state of the photovoltaic DC-to-AC converter of excitation delay startup described in removing.
Wherein, the preferred contactor of described gate-controlled switch, but do not limit to.
In addition, the embodiment of the present invention another photovoltaic parallel in system disclosed, comprises photovoltaic DC-to-AC converter, step-up transformer, gate-controlled switch, and the sample circuit of high side voltage for described step-up transformer of sampling; Wherein:
Described in the low pressure side joint of this step-up transformer, photovoltaic DC-to-AC converter, high-pressure side connect mesohigh electrical network through described gate-controlled switch;
For each photovoltaic DC-to-AC converter described, it is not connected with each other by means of only communication port, is also connected with described gate-controlled switch with described sample circuit respectively, for searching the photovoltaic DC-to-AC converter meeting entry condition in photovoltaic parallel in system; Exciting voltage using mesohigh line voltage as the step-up transformer desired output in described photovoltaic parallel in system, controls all or part of photovoltaic DC-to-AC converter meeting entry condition and carries out excitation delay startup to described step-up transformer; And the photovoltaic DC-to-AC converter controlling to have neither part nor lot in described photovoltaic parallel in system excitation delay startup enters standby lock-out state; Obtain the exciting voltage of the actual output of described step-up transformer; When detecting that the difference of described exciting voltage and mesohigh line voltage drops in error allowed band, connect described step-up transformer and mesohigh electrical network, and have neither part nor lot in the standby lock-out state of the photovoltaic DC-to-AC converter of excitation delay startup described in removing.
Visible, the startup control strategy of photovoltaic parallel in system both can adopt independently equipment to realize, to complete the scheduling to each photovoltaic DC-to-AC converter; Can be integrated in each photovoltaic DC-to-AC converter as functional module again inner, now each photovoltaic DC-to-AC converter realizes intercoming mutually and controlling by communication port.
Wherein, the preferred contactor of described gate-controlled switch, but do not limit to.
In sum, the present invention is before connection step-up transformer and mesohigh electrical network, first control all or part of photovoltaic DC-to-AC converter meeting entry condition and excitation delay startup is carried out to step-up transformer, and standby locking is carried out to all the other photovoltaic DC-to-AC converters, until the exciting voltage of step-up transformer and mesohigh line voltage basically identical time just connect step-up transformer and mesohigh electrical network, remove standby locking; Compared to prior art, the present invention, owing to being connect step-up transformer and mesohigh electrical network under zero pressure difference, can not producing impulse current, therefore can not be damaged by proterctive equipment.
In this specification, each embodiment adopts the mode of going forward one by one to describe, and what each embodiment stressed is the difference with other embodiments, between each embodiment identical similar portion mutually see.For device, system disclosed in embodiment, because it corresponds to the method disclosed in Example, so description is fairly simple, relevant part illustrates see method part.
To the above-mentioned explanation of the disclosed embodiments, professional and technical personnel in the field are realized or uses the present invention.To be apparent for those skilled in the art to the multiple amendment of these embodiments, General Principle as defined herein can without departing from the spirit or scope of the present invention, realize in other embodiments.Therefore, the present invention can not be restricted to these embodiments shown in this article, but will meet the widest scope consistent with principle disclosed herein and features of novelty.
Claims (10)
1. a startup control method for photovoltaic parallel in system, is characterized in that, comprising:
The photovoltaic DC-to-AC converter meeting entry condition is searched in photovoltaic parallel in system;
Exciting voltage using mesohigh line voltage as the step-up transformer desired output in described photovoltaic parallel in system, controls all or part of photovoltaic DC-to-AC converter meeting entry condition and carries out excitation delay startup to described step-up transformer; And the photovoltaic DC-to-AC converter controlling to have neither part nor lot in described photovoltaic parallel in system excitation delay startup enters standby lock-out state;
Obtain the exciting voltage of the actual output of described step-up transformer;
When detecting that the difference of described exciting voltage and mesohigh line voltage drops in error allowed band, connect described step-up transformer and mesohigh electrical network, and have neither part nor lot in the standby lock-out state of the photovoltaic DC-to-AC converter of excitation delay startup described in removing.
2. method according to claim 1, is characterized in that, all or part of photovoltaic DC-to-AC converter meeting entry condition of described control carries out excitation delay startup to described step-up transformer, comprising:
Control a photovoltaic DC-to-AC converter meeting entry condition and independently excitation delay startup is carried out to described step-up transformer.
3. method according to claim 1, is characterized in that, all or part of photovoltaic DC-to-AC converter meeting entry condition of described control carries out excitation delay startup to described step-up transformer, comprising:
Control at least two photovoltaic DC-to-AC converters meeting entry condition and synchronously excitation delay startup is carried out to described step-up transformer.
4. method according to claim 1, is characterized in that, after the exciting voltage of the actual output of the described step-up transformer of described acquisition, also comprises:
If do not detect at the appointed time, described difference drops in described error allowed band, then return the step performing and search the photovoltaic DC-to-AC converter meeting entry condition in photovoltaic parallel in system.
5. a startup control device for photovoltaic parallel in system, is characterized in that, comprising:
Search unit, for searching the photovoltaic DC-to-AC converter meeting entry condition in photovoltaic parallel in system;
Start unit, for the exciting voltage using mesohigh line voltage as the step-up transformer desired output in described photovoltaic parallel in system, controls all or part of photovoltaic DC-to-AC converter meeting entry condition and carries out excitation delay startup to described step-up transformer; And the photovoltaic DC-to-AC converter controlling to have neither part nor lot in described photovoltaic parallel in system excitation delay startup enters standby lock-out state;
Acquiring unit, for obtaining the exciting voltage of the actual output of described step-up transformer;
First processing unit, for when detecting that the difference of described exciting voltage and mesohigh line voltage drops in error allowed band, connect described step-up transformer and mesohigh electrical network, and have neither part nor lot in the standby lock-out state of the photovoltaic DC-to-AC converter of excitation delay startup described in removing.
6. device according to claim 5, is characterized in that, described start unit comprises interlocking start unit;
Described interlocking start unit, for the exciting voltage using mesohigh line voltage as the step-up transformer desired output in described photovoltaic parallel in system, control a photovoltaic DC-to-AC converter meeting entry condition and independently excitation delay startup is carried out to described step-up transformer, and the photovoltaic DC-to-AC converter controlling to have neither part nor lot in described photovoltaic parallel in system excitation delay startup enters standby lock-out state.
7. device according to claim 5, is characterized in that, described start unit comprises synchronous averaging unit;
Described synchronous averaging unit, for the exciting voltage using mesohigh line voltage as the step-up transformer desired output in described photovoltaic parallel in system, control at least two photovoltaic DC-to-AC converters meeting entry condition and synchronously excitation delay startup is carried out to described step-up transformer, and the photovoltaic DC-to-AC converter controlling to have neither part nor lot in described photovoltaic parallel in system excitation delay startup enters standby lock-out state.
8. device according to claim 5, is characterized in that, also comprises:
Second processing unit, if for not detecting that described difference drops in described error allowed band at the appointed time, search unit described in triggering.
9. a photovoltaic parallel in system, comprises photovoltaic DC-to-AC converter, step-up transformer and gate-controlled switch, and described in the low pressure side joint of this step-up transformer, photovoltaic DC-to-AC converter, high-pressure side connect mesohigh electrical network through described gate-controlled switch, it is characterized in that, also comprise:
For the sample circuit of the high side voltage of described step-up transformer of sampling;
And the Centralized Controller be connected with described sample circuit with described photovoltaic DC-to-AC converter, described gate-controlled switch respectively, for searching the photovoltaic DC-to-AC converter meeting entry condition in photovoltaic parallel in system; Exciting voltage using mesohigh line voltage as the step-up transformer desired output in described photovoltaic parallel in system, controls all or part of photovoltaic DC-to-AC converter meeting entry condition and carries out excitation delay startup to described step-up transformer; And the photovoltaic DC-to-AC converter controlling to have neither part nor lot in described photovoltaic parallel in system excitation delay startup enters standby lock-out state; Obtain the exciting voltage of the actual output of described step-up transformer; When detecting that the difference of described exciting voltage and mesohigh line voltage drops in error allowed band, connect described step-up transformer and mesohigh electrical network, and have neither part nor lot in the standby lock-out state of the photovoltaic DC-to-AC converter of excitation delay startup described in removing.
10. a photovoltaic parallel in system, comprises photovoltaic DC-to-AC converter, step-up transformer and gate-controlled switch, and described in the low pressure side joint of this step-up transformer, photovoltaic DC-to-AC converter, high-pressure side connect mesohigh electrical network through described gate-controlled switch, it is characterized in that, also comprise:
For the sample circuit of the high side voltage of described step-up transformer of sampling;
Each photovoltaic DC-to-AC converter described is connected with each other by communication port, and is connected with described gate-controlled switch with described sample circuit respectively, for searching the photovoltaic DC-to-AC converter meeting entry condition in photovoltaic parallel in system; Exciting voltage using mesohigh line voltage as the step-up transformer desired output in described photovoltaic parallel in system, controls all or part of photovoltaic DC-to-AC converter meeting entry condition and carries out excitation delay startup to described step-up transformer; And the photovoltaic DC-to-AC converter controlling to have neither part nor lot in described photovoltaic parallel in system excitation delay startup enters standby lock-out state; Obtain the exciting voltage of the actual output of described step-up transformer; When detecting that the difference of described exciting voltage and mesohigh line voltage drops in error allowed band, connect described step-up transformer and mesohigh electrical network, and have neither part nor lot in the standby lock-out state of the photovoltaic DC-to-AC converter of excitation delay startup described in removing.
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