WO2023240980A1 - 一种光伏系统及其优化器定位方法 - Google Patents

一种光伏系统及其优化器定位方法 Download PDF

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WO2023240980A1
WO2023240980A1 PCT/CN2022/140971 CN2022140971W WO2023240980A1 WO 2023240980 A1 WO2023240980 A1 WO 2023240980A1 CN 2022140971 W CN2022140971 W CN 2022140971W WO 2023240980 A1 WO2023240980 A1 WO 2023240980A1
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optimizer
photovoltaic
inverter
output voltage
string
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PCT/CN2022/140971
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English (en)
French (fr)
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许晨嘉
姚克亮
杨宇
王新宇
陶庭欢
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阳光电源（上海）有限公司
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Publication of WO2023240980A1 publication Critical patent/WO2023240980A1/zh

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H02J3/381—Dispersed generators
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
    • H02J2300/20—The dispersed energy generation being of renewable origin
    • H02J2300/22—The renewable source being solar energy
    • H02J2300/24—The renewable source being solar energy of photovoltaic origin
    • H02J2300/26—The renewable source being solar energy of photovoltaic origin involving maximum power point tracking control for photovoltaic sources
    • 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

Definitions

  • the present application relates to the field of photovoltaic power generation technology, and in particular to a photovoltaic system and its optimizer positioning method.
  • the optimizer in the photovoltaic system is specifically a DC input and DC output MLPE (Module Level Power Electronics, component-level power electronics equipment).
  • MLPE Module Level Power Electronics, component-level power electronics equipment.
  • the inverter and optimizer communicate through PLC (Power Line Communication).
  • the inverter contains a PLC master node controller, and the optimizer is the slave node of the PLC.
  • the inverter master node needs to know the topological location information of each optimizer connected to the inverter system to facilitate command control and status during later operations. position. If the inverter does not have the topological location information of the optimizer, when searching for the optimizer, the optimizer information in other systems may be searched due to crosstalk problems, affecting the judgment and error control of the inverter master node.
  • each optimizer still needs to be entered manually in sequence; but if the entry process only realizes the mutual correspondence between each optimizer and each Boost circuit of the inverter, when the photovoltaic group connected to the Boost circuit
  • the number of strings is greater than 1
  • the inverter master node does not know which optimizers are in the same string, it will also affect its judgment of long strings and issue limiting values incorrectly, causing the sum of the output voltages of the entire string of optimizers to exceed
  • the inverter can withstand voltages that can cause overvoltage damage to the inverter.
  • This application provides a photovoltaic system and its optimizer positioning method to automatically realize optimizer differentiation between different photovoltaic strings connected to the Boost circuit.
  • the first aspect of this application provides an optimizer positioning method for parallel photovoltaic strings in a photovoltaic system.
  • the photovoltaic system includes: an inverter and corresponding photovoltaic strings connected to each boost circuit in the front stage of the DC bus; the optimization Device positioning methods include:
  • the inverter sets the output voltage limit value and/or the output current limit value to the optimizer in each photovoltaic string
  • the inverter controls the startup of each optimizer
  • the inverter controls one of the optimizers at least once to change the output voltage, and uses the electrical status of each optimizer to distinguish the photovoltaic strings to which they belong.
  • change the output voltage including: active bypass; or,
  • the method further includes: the inverter controls each of the optimizers.
  • the output voltage of the device reaches the output voltage limit value; and changing the output voltage includes: increasing or decreasing the output voltage limit value.
  • the inverter controls one of the optimizers to change the output voltage at least once, and uses the electrical status of each optimizer to distinguish its respective photovoltaic strings, including:
  • the inverter controls any one of the optimizers whose photovoltaic string it belongs to is not determined to change the output voltage
  • each time the inverter controls the corresponding optimizer to change the output voltage it detects the electrical state of each optimizer, and determines the state of the optimizer that changes the output voltage according to each electrical state.
  • Each of the optimizers of the same photovoltaic string determines that other optimizers belong to other photovoltaic strings until the inverter realizes the distinction between the photovoltaic strings to which each of the corresponding optimizers belongs.
  • the electrical state includes: at least one of output voltage, output current and working state;
  • each of the optimizers in the same photovoltaic string as the optimizer that changes the output voltage includes:
  • the optimizer satisfies at least one of the following conditions: output voltage is greater than a preset voltage value, output current is less than a preset negative current value, and the working state is a reverse input state;
  • each of the optimizers in the same photovoltaic string as the optimizer that changes the output voltage includes:
  • the optimizer satisfies at least one condition of the output voltage being less than the preset voltage value, the output current being greater than the preset positive current value, and the working state being a forward output state.
  • the output voltage is the output voltage limit value instead of the condition that the output voltage is greater than the preset voltage value; And replace the condition that the output voltage is less than the preset voltage value with the output voltage being less than the output voltage limit value;
  • the output current limit value with the output current being negative is used instead of the condition that the output current is less than the preset negative current value; and
  • the output current limit value with the output current being positive replaces the condition that the output current is greater than the preset positive current value.
  • the inverter controls one of the optimizers at least once to change the output voltage, it also includes:
  • the inverter determines whether the electrical status of each optimizer in the parallel photovoltaic string connected to the Boost circuit is consistent
  • the corresponding parallel photovoltaic string is determined to be the parallel non-voltage difference photovoltaic string
  • the inverter first determines that the optimizer whose output current is greater than the preset positive current value or less than the preset negative current value belongs to the same photovoltaic string; and then the corresponding parallel photovoltaic group is When the number of photovoltaic strings in a string is greater than 2, it is determined that the other photovoltaic strings are the parallel-connected photovoltaic strings without voltage difference.
  • the output current limit value with the output current being positive replaces the condition that the output current is greater than the preset positive current value
  • the condition that the output current is less than the preset negative current value is replaced by the output current limit value in which the output current is negative.
  • the inverter determines whether the electrical status of each optimizer in the parallel photovoltaic string connected to the Boost circuit is consistent, it also includes:
  • the inverter determines whether the optimizers connected to each Boost circuit have been distinguished
  • the inverter controls the input end of the corresponding Boost circuit to maintain a short-circuit state for a preset time according to the preset rules, and optimizes all the optimization according to each short-circuit state.
  • the output electrical parameters of the inverter are used to determine the optimizer connected to each Boost circuit; and then the inverter is executed to determine whether the electrical status of each optimizer in the parallel photovoltaic string connected to the Boost circuit is consistent.
  • the output electrical parameters include: output voltage and/or output current
  • the inverter determines the optimizer connected to each Boost circuit based on the output electrical parameters of all optimizers in each short-circuit state, including:
  • the inverter determines that it is connected to an input end short-circuit state.
  • Boost circuit for each optimizer whose output voltage is not zero and/or whose output current is zero, the inverter determines that it is not connected to the Boost circuit in a short-circuit state at the input end.
  • the inverter controls the corresponding Boost circuit input terminals to maintain a short-circuit state for a preset time according to preset rules, including:
  • the inverter controls the input terminals of each Boost circuit one by one to maintain a short-circuit state for a preset time; or,
  • the inverter groups all the Boost circuits successively, and each time controls the input terminals of some of the Boost circuits in the current group to maintain a short-circuit state for a preset time, and groups the current group again according to the different states of the input terminals of the Boost circuit until the current Only one Boost circuit is included in the group.
  • the second aspect of this application also provides a photovoltaic system, including: an inverter and at least one photovoltaic string;
  • An optimizer with one or at least two output terminals connected in series is provided between the two ends of the photovoltaic string, and the input terminal of the optimizer is connected to at least one photovoltaic component;
  • the DC bus front stage of the inverter is provided with at least one Boost circuit, and the input end of each Boost circuit is used to connect at least one corresponding photovoltaic string;
  • the controller in the inverter serves as a master node to communicate with each of the optimizers, and is used to execute the optimizer positioning method for parallel photovoltaic strings in the photovoltaic system as described in any one of the above first aspects.
  • each Boost circuit is independent of the inverter; or,
  • Each Boost circuit is integrated in the inverter, and the output end of each Boost circuit is connected to the DC side of the inverter circuit in the inverter through the DC bus.
  • the input terminals of the Boost circuit are respectively connected to: one connection port on the DC side of the inverter, or at least two connection ports connected in parallel;
  • connection port is connected to one photovoltaic string, or the connection port is connected in parallel to at least two photovoltaic strings through a bus terminal.
  • This application provides an optimizer positioning method for parallel photovoltaic strings in a photovoltaic system.
  • the inverter sets the output voltage limit value and/or output current limit value to the optimizer in each photovoltaic string, and controls the startup of each optimizer.
  • the inverter will control one of the optimizers at least once to change the output voltage, and actively create the voltage difference between the strings for the parallel-connected photovoltaic strings with no voltage difference, and then Construct long and short strings connected in parallel to form a circulating current; since the circulating current will cause the electrical states of the optimizers in the long string and the short string to be different, the electrical states of each optimizer can be used to distinguish the photovoltaic strings to which they belong. , and then automatically realize the optimizer distinction between different photovoltaic strings connected to the Boost circuit, that is, the string-level positioning of the optimizer is realized.
  • Figures 1 to 3 are respectively three flow charts of optimizer positioning methods for parallel photovoltaic strings in photovoltaic systems provided by embodiments of the present application;
  • Figure 4 is a schematic structural diagram of a photovoltaic system provided by an embodiment of the present application.
  • Figure 5 is a schematic structural diagram of a photovoltaic string provided by an embodiment of the present application.
  • Figure 6 is a schematic diagram of the specific structure of the photovoltaic system provided by the embodiment of the present application.
  • This application provides an optimizer positioning method for a photovoltaic system to automatically differentiate the optimizers between different photovoltaic strings connected to the Boost circuit.
  • the photovoltaic system includes: an inverter, and corresponding photovoltaic strings connected to each Boost circuit in the front stage of the inverter's DC bus; and at least one Boost circuit is connected to at least two parallel photovoltaic strings.
  • the optimizer positioning method for parallel photovoltaic strings in this photovoltaic system includes:
  • the inverter sets the output voltage limit value and/or the output current limit value to the optimizer in each photovoltaic string.
  • the values of both can be set according to actual needs, both of which are protected in this application. within the range.
  • the inverter controls the start of each optimizer.
  • the inverter controls the startup process of each optimizer. Specifically, the inverter sends activation instructions to each optimizer, causing each optimizer to enter the working mode and increase the output voltage through soft start. If the output voltage limit value Ulmt has been set in step S101, the increase in the output voltage of each optimizer will eventually reach the output voltage limit value Ulmt. If the output voltage limit value Ulmt is not set in step S101, the increase in the output voltage of each optimizer can eventually reach the rated output voltage.
  • step S103 needs to be performed.
  • step S103 needs to be performed on the connected parallel photovoltaic strings with no voltage difference respectively.
  • the inverter controls one of the optimizers at least once to change the output voltage, and uses the electrical status of each optimizer to distinguish its respective photovoltaic strings.
  • controlling the optimizer to change the output voltage can be achieved by directly controlling the active bypass of the corresponding optimizer. At this time, the output voltage of the corresponding optimizer is zero, and the voltage of the photovoltaic string to which it belongs will decrease.
  • the control optimizer in step S103 changes the output voltage, or by increasing This is achieved by adjusting the output voltage limit value Ulmt of the corresponding optimizer. At this time, the output voltage of the corresponding optimizer will also increase accordingly; alternatively, the control optimizer in step S103 changes the output voltage, or by reducing the output voltage of the corresponding optimizer.
  • the output voltage limit value Ulmt is realized. At this time, the output voltage of the corresponding optimizer will also be reduced, for example, to between zero and the output voltage limit value Ulmt in S101.
  • Boost circuit with at least two photovoltaic strings connected in parallel with the same voltage
  • the inverter controls any optimizer to actively bypass or reduce the output voltage limit value Ulmt
  • it will cause the voltage of the photovoltaic string to which it belongs to decrease, equivalently
  • the photovoltaic string becomes shorter, so it can be called a short string; while other photovoltaic strings maintain the original voltage, which is equivalent to maintaining the original length, and can be called long strings relative to the short string.
  • the inverter controls any of the optimizers to increase the output voltage limit value Ulmt it will cause it to become a long string; while other photovoltaic strings will become short strings.
  • each optimizer in the short string is -Ilmt, that is, the negative output current limit value; at the same time, each optimizer in the long string is in the positive output state, and each optimizer in the short string All are in reverse input state.
  • the output voltage of each optimizer in the short string is its rated output voltage, while the output terminal of each optimizer in the long string The shared voltage will be lower than its rated output voltage but greater than 0V; and when the output voltage limit value Ulmt is set in step S101, the output voltage of each optimizer in the short string is the output voltage limit value Ulmt, and The voltage shared by the output terminals of each optimizer in the long string will be lower than the output voltage limit value Ulmt but will also be greater than 0V.
  • step S101 Based on at least one of the output voltage, output current and working state of each optimizer, as the electrical state of the corresponding optimizer, at least each optimizer in the photovoltaic string whose voltage is changed in the current state can be identified; in step S101
  • the output voltage limit value Ulmt and the output current limit value Ilmt are set at the same time as an example to illustrate: If the corresponding photovoltaic string is changed to a short string, the specific performance of each optimizer is: the output voltage is Ulmt, the output current is - Ilmt and the working state are reverse input states.
  • These optimizers belong to the same photovoltaic string as the optimizer whose output voltage is currently reduced.
  • each optimizer belongs to the same photovoltaic string as the optimizer whose output voltage is currently increased. If only two PV strings are connected in parallel, it can be determined that each remaining optimizer belongs to another PV string. If there are more photovoltaic strings connected in parallel, the above-mentioned control of changing the output voltage can be performed multiple times to identify multiple photovoltaic strings whose voltages have been changed, until all optimizers have identified the photovoltaic strings to which they belong, that is, Optimizer positioning for all parallel-connected photovoltaic strings without voltage difference can be achieved.
  • This embodiment provides an optimizer positioning method for parallel photovoltaic strings in the photovoltaic system.
  • the inverter controls one of the optimizers to change the output voltage, it can actively create an inter-string voltage difference for the corresponding photovoltaic string, and then Construct long and short strings connected in parallel to form a circulating current; since the circulating current will cause the electrical states of the optimizers in the long string and the short string to be different, the electrical states of each optimizer can be used to distinguish the photovoltaic strings to which they belong. , and then automatically realize the optimizer distinction between different photovoltaic strings connected to the Boost circuit, that is, the string-level positioning of the optimizer is realized, which is conducive to the differential control of each photovoltaic string by the inverter.
  • step S103 of the optimizer positioning method for parallel photovoltaic strings in the photovoltaic system the inverter controls one of the optimizers at least once to change the output voltage, and uses the electrical parameters of each optimizer to change the output voltage.
  • the status distinguishes the photovoltaic strings to which they belong, specifically including: the inverter controls any optimizer to change the output voltage from the optimizer that has never determined the photovoltaic string to which it belongs; and, the inverter controls the corresponding optimizer each time After changing the output voltage, the electrical status of each optimizer is detected, and based on each electrical status, each optimizer in the same photovoltaic string as the optimizer that changes the output voltage is determined, and other optimizers are determined to belong to other photovoltaic strings. Until the inverter realizes the distinction between the photovoltaic strings to which each optimizer belongs.
  • the electrical state includes: at least one of output voltage, output current and working state; at this time:
  • each of the above-mentioned optimizers in the same photovoltaic string as the optimizer that changes the output voltage will be an optimizer that meets at least one of the following conditions: the output voltage is greater than the preset The voltage value and output current are less than the preset negative current value and the working state is the reverse input state.
  • each optimizer in the same photovoltaic string as the optimizer that changes the output voltage specifically an optimizer that meets at least one of the following conditions: the output voltage is less than the preset voltage value , the output current is greater than the preset positive current value and the working state is the forward output state.
  • the output voltage limit value Ulmt is set in step S101, then the condition that the output voltage is greater than the preset voltage value under the above two output voltage changing directions can be replaced by: the output voltage is the output voltage limit value Ulmt; and the condition that the output voltage is less than the preset voltage value can be replaced by: the output voltage is less than the output voltage limit value Ulmt.
  • the condition that the output current is less than the preset negative current value under the above two output voltage changing directions can be replaced by: the output current limit value Ilmt where the output current is negative;
  • the condition that the output current is greater than the preset positive current value can be replaced by: the output current limit value Ilmt where the output current is positive.
  • step S101 Take the example of setting the output voltage limit value Ulmt and the output current limit value Ilmt at the same time in step S101, and changing the direction of the output voltage to decrease: for at least two photovoltaic strings connected in parallel and with the same voltage connected to the Boost circuit , after the inverter controls any optimizer to reduce the output voltage, a circulating current will form between the long and short strings connected in parallel.
  • the output current of each optimizer in the short string is -Ilmt (that is, the negative output current limit value ); when two photovoltaic strings are connected in parallel, there is only one long string, then the output current of each optimizer in the long string is the output current limit value Ilmt; when three photovoltaic strings are connected in parallel, there will be two long string, then the output current of each optimizer in the long string is Ilmt/2; by analogy, when n photovoltaic strings are connected in parallel, there will be n-1 long strings, then the output current of each optimizer in the long string Both are Ilmt/(n-1).
  • each optimizer in the long string is in the forward output state, while each optimizer in the short string is in the reverse input state.
  • the output voltage of each optimizer in the short string is the output voltage limit value Ulmt, while the output voltage of each optimizer in the long string will be between 0 and Ulmt.
  • each optimizer belonging to the short string in the current state can be identified, and the optimization of these optimizers and the current reduced output voltage can be determined.
  • devices belong to the same photovoltaic string.
  • each optimizer with an output voltage between 0 and Ulmt, an output current of Ilmt, and a forward output state belongs to the above long string, that is, another photovoltaic string. Group string. The principle of changing the direction of the output voltage to increase can be deduced in the same way and will not be described again.
  • n is an integer greater than 2
  • the remaining optimizers for example, changing the direction of the output voltage for the first time are When decreasing, each optimizer with an output voltage between 0 and Ulmt, an output current of Ilmt/(n-1), and a forward output state can be determined to belong to another n-1 photovoltaic strings.
  • the specific photovoltaic strings to which they belong cannot yet be determined; although these photovoltaic strings are currently of the same length, after controlling any of the optimizers to change the output voltage, new short strings and long strings can be constructed again, and then passed Once the above-mentioned electrical status identification process is completed, the optimizers in the photovoltaic strings whose voltage has been changed can be distinguished again; the above process is repeated until the optimizers in all photovoltaic strings are located, and voltage-free operation for all parallel connection can be realized. Optimizer positioning of poor PV strings.
  • each optimizer is started, the The electrical status of each optimizer is judged once. If the electrical status of each optimizer in the parallel photovoltaic string is inconsistent, the short string or the long string whose length is different from other photovoltaic strings can be directly identified; if two photovoltaic strings If more photovoltaic strings are connected in parallel, a photovoltaic string with a special length can be identified first, thus reducing the need to perform the above-mentioned change of output voltage. control process.
  • this embodiment provides an optimizer positioning method for parallel photovoltaic strings in the photovoltaic system, as shown in Figure 2.
  • the Boost circuit Before executing step S103, it also includes:
  • the inverter determines whether the electrical status of each optimizer is consistent.
  • step S103 is performed directly. If the electrical states are not consistent, step S202 is first executed, and then if the number of photovoltaic strings in the corresponding parallel photovoltaic string is greater than 2, it is determined that the other photovoltaic strings are parallel photovoltaic strings without voltage difference, and step S103 is executed. .
  • the inverter determines that the optimizer whose output current is greater than the preset positive current value or less than the preset negative current value belongs to the same photovoltaic string.
  • step S202 the condition that the output current is greater than the preset positive current value can be replaced by the output current limit value where the output current is positive; and the output current is less than the preset positive current value.
  • the condition for a negative current value can be replaced by an output current limit value where the output current is negative.
  • the input terminal of a certain Boost circuit has three photovoltaic strings connected in parallel. Two of the photovoltaic strings have the same length and are both longer than the other photovoltaic string. That is, the input terminal has two long strings and one short string connected in parallel. ; Then after each optimizer is started, the two long strings inject current into the short string.
  • the electrical status of the optimizer in the short string is: the output voltage is Ulmt, the output current is -Ilmt, and the working state is the reverse input state.
  • the electrical status of the optimizer in a long string is as follows: the output voltage is between 0 and Ulmt, the output current is Ilmt/2, and the working state is forward output state; then each optimizer in the short string can be identified, and then the Two long strings execute step S103.
  • the input terminal of a Boost circuit has three photovoltaic strings connected in parallel. Two of the photovoltaic strings have the same length and are shorter than the other photovoltaic string. That is, the input terminal has two short strings and one long string connected in parallel. string; then after each optimizer is started, the long string pours current into the two short strings.
  • the electrical status of the optimizer in the long string is as follows: the output voltage is between 0 and Ulmt, the output current is Ilmt, and the working state is forward.
  • Output status the electrical status of the optimizers in the two short strings is as follows: the output voltage is Ulmt, the output current is -Ilmt/2, and the working state is the reverse input state; then each optimizer in the long string can be identified, and then Step S103 is performed on the two short strings.
  • each optimizer in a photovoltaic string with a special length can be directly determined, making the string-level positioning process of the optimizer simpler.
  • each optimizer and each Boost circuit of the inverter can be realized through any of the above embodiments. Positioning; however, if the above-mentioned manual entry process is not performed after the system is installed, or if the manual entry process is considered to be inefficient and error-prone, the inverter can be used to first distinguish the photovoltaic strings connected to each Boost circuit. That is to say, the optimizer positioning method for parallel photovoltaic strings in the photovoltaic system, based on the above embodiment, can also be shown in Figure 3 (taking Figure 2 as an example), which after step S102 ,Also includes:
  • the inverter determines whether the optimizers connected to each Boost circuit have been distinguished.
  • step S201 is performed for the parallel photovoltaic strings connected to the Boost circuit.
  • step S302 is executed first, and then step S201 is executed for the parallel photovoltaic strings connected to the Boost circuit.
  • the inverter controls the input end of the corresponding Boost circuit to maintain a short-circuit state for a preset time according to the preset rules, and determines the optimizer connected to each Boost circuit based on the output electrical parameters of all optimizers in each short-circuit state.
  • the inverter controls the input terminals of the corresponding Boost circuits to maintain the short-circuit state for the preset duration according to the preset rules. Specifically, the inverter controls the input terminals of each Boost circuit one by one to maintain the short-circuit state for the preset duration; Alternatively, it can also be: the inverter groups all the Boost circuits successively, each time controlling some of the input terminals of the Boost circuit in the current group to maintain a short-circuit state for a preset time, and re-processing the current group according to the different states of the input terminals of the Boost circuit. Group until only one Boost circuit is included in the current group.
  • the output electrical parameters may include: output voltage, and/or output current; in step S302, the inverter determines the connection points of each Boost circuit based on the output electrical parameters of all optimizers in each short-circuit state.
  • the optimizer may specifically include: in each short-circuit state, for each optimizer whose output voltage is zero and/or the output current is greater than the preset current value or is the output current limit value, the inverter determines that it is connected to the input terminal Boost circuit in a short-circuit state; for each optimizer whose output voltage is not zero and/or whose output current is zero, the inverter determines that it is not connected to a Boost circuit that is in a short-circuit state at the input end.
  • step S101 If the output current limit value Ilmt is not set in step S101, the output current of each optimizer in the connected photovoltaic string of the Boost circuit in a short-circuit state at the input end will reach the short-circuit current, which can be identified by being greater than a preset current value. ; And if the output current limit value Ilmt has been set in step S101, then the output current of each optimizer in the connected photovoltaic string of the Boost circuit with a short-circuited input terminal can only reach the output current limit value Ilmt.
  • the inverter needs to fully automatically determine the Boost circuit and string-level positioning connected to each optimizer. After it is powered on, it first sends search instructions to each optimizer, so that each optimizer will separately The serial number is sent to the inverter; then the output voltage limit value Ulmt and the output current limit value Ilmt are set to the optimizer through step S101, and then through step S102, each optimizer is controlled to start and increase their respective output voltages to the output voltage.
  • the limit value Ulmt then, perform steps S301 and S302 to determine the Boost circuit connected to each optimizer; at this time, for the parallel photovoltaic string connected to the Boost circuit, first identify the special length of the photovoltaic string through steps S201 and S202.
  • step S103 can be performed separately on the parallel non-voltage difference photovoltaic strings connected to the corresponding Boost circuit, and then through the difference between the electrical states of the optimizers in these photovoltaic strings, these optimizations can be
  • the optimizers are classified according to the photovoltaic strings to which they belong, and all optimizers belonging to the same photovoltaic string are located.
  • the above process can realize automatic networking and positioning of all optimizers at the group and series levels, avoid the manual process of entering information for each optimizer, improve the efficiency of networking and reduce the probability of errors.
  • FIG. 4 Another embodiment of the present application also provides a photovoltaic system, as shown in Figure 4, including: an inverter 200 and at least one photovoltaic string 100; wherein:
  • At least one Boost circuit 201 is provided at the front stage of the DC bus of the inverter 200 , and the input end of each Boost circuit 201 is used to connect at least one corresponding photovoltaic string 100 .
  • each Boost circuit 201 can be integrated in the inverter 200, and the output end of each Boost circuit 201 is connected to the DC side of the inverter circuit 202 in the inverter 200 through a DC bus. .
  • each Boost circuit 201 can also be independent of the inverter 200 (not shown), depending on its specific application environment, and both are within the protection scope of this application.
  • the inverter 200 is connected to the corresponding applicable single-phase or three-phase power grid according to different models.
  • an optimizer 102 with one or at least two output terminals connected in series is disposed between two ends of the photovoltaic string 100 , and the input terminal of the optimizer 102 is connected to at least one photovoltaic module 101 .
  • the controller in the inverter 200 serves as a master node to communicate with each optimizer 102 and is used to execute the optimizer positioning method for parallel photovoltaic strings in the photovoltaic system described in any of the above embodiments.
  • the controller in the inverter 200 serves as a master node to communicate with each optimizer 102 and is used to execute the optimizer positioning method for parallel photovoltaic strings in the photovoltaic system described in any of the above embodiments.
  • the inverter 200 may contain m Boost circuits (as shown in Figure 6 Boost 1,...Boost x,...Boost m) shown below, m is a positive integer greater than or equal to 1.
  • each Boost circuit 201 can be connected to only one connection port on the DC side of the inverter 200, or it can also be connected to at least two parallel connection ports on the DC side of the inverter 200; each Boost circuit
  • the settings of the 201 input terminals may be the same or different, depending on the specific application environment, and are all within the protection scope of this application.
  • the connection port connected to the input end of each Boost circuit 201 can be connected to one photovoltaic string 100, or at least two photovoltaic strings 100 can be connected in parallel through the bus terminal; it depends on the specific application environment, both of which are discussed here. within the scope of protection applied for.
  • each Boost circuit 201 has an input terminal, which can also be called an MPPT port.
  • Each MPPT port can be divided into two parallel connection ports inside the inverter 200, and the connection interface can be called a PV port.
  • each MPPT port can also directly become a PV port.
  • Each PV port can be connected to one photovoltaic string 100, or two parallel photovoltaic strings 100 can be connected through the bus terminal. No less than 2 photovoltaic strings 100 can be connected to a system.
  • each photovoltaic string 100 includes n photovoltaic modules (photovoltaic module 1 to photovoltaic module n as shown in the figure), n is a positive integer greater than or equal to 2, and when the inverter When the inverter 200 is a single phase, n is less than or equal to 25; when the inverter 200 is a three phase, n is less than or equal to 50. Since this system is a system in which the optimizer 102 is fully installed, each photovoltaic module must include one photovoltaic unit and one optimizer 102 .
  • the photovoltaic unit includes at least one photovoltaic component 101.
  • the photovoltaic unit is connected to the input terminal of the optimizer 102.
  • the output terminals of all optimizers 102 in the photovoltaic string 100 are connected in series with each other, that is, the positive output terminal of the optimizer 102 is connected to the negative terminal of the previous optimizer 102.
  • the output terminal, the negative output terminal of the optimizer 102 is connected to the positive output terminal of the next optimizer 102 and finally connected to a PV port of the inverter 200 .
  • the MPPT port of each Boost circuit may not be connected to the photovoltaic string 100, or 1 to 3 photovoltaic strings 100 may be connected, but there is at least one MPPT port connected to the Boost circuit.
  • Figure 6 shows a parallel photovoltaic string structure in a photovoltaic system in which the optimizer 102 is fully installed, which consists of two photovoltaic strings (photovoltaic string 1 and photovoltaic string 2 as shown in the figure) 100 connected in parallel Formed, where photovoltaic string 1 contains n1 photovoltaic modules, photovoltaic string 2 contains n2 photovoltaic modules, n1 and n2 can be the same or different; if n1 and n2 are the same, then this pair of parallel photovoltaic strings can be called are the same parallel string; if n1 and n2 are different, this pair of parallel photovoltaic strings can be called a differential parallel string.
  • the controller of the inverter realizes automatic networking through step S302 described in the above embodiment, or can distinguish all optimizers of parallel photovoltaic strings connected to the same MPPT port through manually entered information. information, but does not distinguish the specific PV string where each optimizer is located.
  • the inverter master node will send setting instructions to each optimizer, including the output voltage limit value Ulmt and the output current limit value Ilmt, both of which can be set according to actual needs.
  • each optimizer is in a safe mode that outputs 1V.
  • the inverter master node will broadcast an activation command. After receiving the activation command, the optimizer will switch from the safe mode to the working mode, start a soft start, and gradually increase the output voltage. Until the output voltage limit value Ulmt is reached. The inverter master node then collects the voltage and current status of all optimizers.
  • step S201 the inverter master node can judge based on the voltage and current state after the optimizer is started: if all optimizers have an output voltage of Ulmt and an output current of 0A, it means that there is no circulating current, and it can be determined that the parallel photovoltaic strings are the same parallel strings (that is, the above-mentioned parallel photovoltaic strings without voltage difference); if the output voltage of some of the optimizers is between Ulmt and 0V, the output current is Ilmt, and the output voltage of another part of the optimizer is Ulmt and the output current is -Ilmt, it means that the lengths of the parallel photovoltaic strings are different, that is, the number of optimizers in the parallel photovoltaic strings shown in Figure 6 is different, it can The parallel photovoltaic string is determined to be a differential parallel string.
  • the inverter master node can arbitrarily select one of the optimizers and send it an active bypass instruction.
  • the optimizer After receiving the active bypass command, the optimizer will change from the working mode to the active bypass mode. Its output will be bypassed and there will be no output voltage, causing the two photovoltaic groups in the structure shown in Figure 6 to be originally the same parallel string. The strings form differences, and circulation occurs.
  • the inverter master node will collect the voltage and current status of all optimizers.
  • the inverter master node will make a judgment based on the voltage and current status after the optimizer is started: all optimizers with an output voltage between Ulmt and 0V and an output current of Ilmt can be positioned as the same photovoltaic string; and all optimizers Optimizers with output voltage Ulmt and output current -Ilmt, as well as actively bypassed optimizers, can be positioned as another PV string. At this point, positioning is complete and can be ended.
  • the photovoltaic string to which the optimizer belongs can be automatically distinguished for parallel photovoltaic strings, and the string-level positioning of the optimizer can be achieved.

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Abstract

本申请提供一种光伏系统及其优化器定位方法，该优化器定位方法首先由逆变器向各光伏组串中的优化器设置输出电压限制值和/或输出电流限制值，并控制各优化器启动；然后，对于Boost电路所接的并联无压差光伏组串，逆变器将至少一次控制其中一个优化器改变输出电压，主动为该并联无压差光伏组串制造组串间压差，进而构建并联连接的长串和短串，以形成环流；由于环流会导致长串和短串内优化器的电气状态有所不同，所以可以以各优化器的电气状态区分其各自所属的光伏组串，进而自动实现了对于Boost电路所接不同光伏组串之间的优化器区分，也即实现了对于优化器的组串级定位。

Description

一种光伏系统及其优化器定位方法
本申请要求于2022年06月17日提交中国专利局、申请号为202210686194.X、发明名称为“一种光伏系统及其优化器定位方法”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及光伏发电技术领域，特别涉及一种光伏系统及其优化器定位方法。
背景技术
光伏系统中的优化器，即光伏功率优化器，其具体是一种直流输入、直流输出的MLPE(Module Level Power Electronics，组件级别电力电子设备)。其通过和光伏组件的串接，采取预测电流与电压技术，保障了光伏组件始终处于最优工作状态；用以解决光伏电站中由于阴影遮挡、朝向不一致或组件电气规格差异对发电量的影响，实现光伏组件的最大功率输出，提升系统发电量。
在安装有优化器的太阳能光伏发电系统中，逆变器和优化器是通过PLC(Power Line Communication，电力线载波通信)进行通信的。其中，逆变器中包含一个PLC主节点控制器，优化器则是PLC的从节点。在该系统中的优化器和逆变器安装完成之后，逆变器主节点需要获知接在该逆变器系统中的各优化器的拓扑位置信息，以便于后期运行过程中进行指令控制与状态定位。如果逆变器没有优化器的拓扑位置信息，则在搜寻优化器时，可能会由于串扰的问题而搜寻到其它系统中的优化器信息，影响逆变器主节点的判断和错误控制。
目前每个优化器的拓扑位置信息，尚需要人工手动按顺序录入；但如果该录入过程只实现了各优化器与逆变器各Boost电路之间的相互对应，则当Boost电路所接光伏组串的数量大于1时，若逆变器主节点不清楚哪些优化器在同一串，还会影响其对于长串的判断，错误下发限幅值，使得整串优化器的输出电压之和超出逆变器可承受电压，导致逆变器过压损坏。
发明内容
本申请提供一种光伏系统及其优化器定位方法，以自动实现对于Boost电路所接不同光伏组串之间的优化器区分。
为实现上述目的，本申请提供如下技术方案：
本申请第一方面提供了一种光伏系统中并联光伏组串的优化器定位方法，光伏系统中包括：逆变器及其直流母线前级各Boost电路所接的相应光伏组串；所述优化器定位方法包括：
所述逆变器向各光伏组串中的优化器设置输出电压限制值和/或输出电流限制值；
所述逆变器控制各所述优化器启动；
对于Boost电路所接的并联无压差光伏组串，所述逆变器至少一次控制其中一个所述优化器改变输出电压，并以各所述优化器的电气状态区分其各自所属的光伏组串。
可选的，改变输出电压，包括：主动旁路；或者，
若所述逆变器已向各所述优化器设置所述输出电压限制值，则在所述逆变器控制各所述优化器启动之后，还包括：所述逆变器控制各所述优化器的输出电压达到所述输出电压限制值；且，改变输出电压，包括：提高或降低所述输出电压限制值。
可选的，所述逆变器至少一次控制其中一个所述优化器改变输出电压，并以各所述优化器的电气状态区分其各自所属的光伏组串，包括：
所述逆变器从未确定所属光伏组串的所述优化器中，控制其中任一所述优化器改变输出电压；
所述逆变器在每次控制相应所述优化器改变输出电压后，检测各所述优化器的所述电气状态，并根据各所述电气状态，确定与改变输出电压的所述优化器处于同一光伏组串的各所述优化器，并确定其他所述优化器属于其他光伏组串，直至所述逆变器实现对于相应各所述优化器所属光伏组串的区分。
可选的，所述电气状态包括：输出电压、输出电流及工作状态中的至少一种；
若改变输出电压的方向为减小，则与改变输出电压的所述优化器处于同一光伏组串的各所述优化器，包括：
满足输出电压大于预设电压值、输出电流小于预设负电流值及工作状态为反向输入状态中至少一种条件的所述优化器；
若改变输出电压的方向为增大，则与改变输出电压的所述优化器处于同一光伏组串的各所述优化器，包括：
满足输出电压小于所述预设电压值、输出电流大于预设正电流值及工作状态为正向输出状态中至少一种条件的所述优化器。
可选的，若所述逆变器已向各所述优化器设置所述输出电压限制值，则以输出电压为所述输出电压限制值，代替输出电压大于所述预设电压值的条件；并以输出电压小于所述输出电压限制值，代替输出电压小于所述预设电压值的条件；
若所述逆变器已向各所述优化器设置所述输出电流限制值，则以输出电流为负的所述输出电流限制值，代替输出电流小于所述预设负电流值的条件；并以输出电流为正的所述输出电流限制值，代替输出电流大于所述预设正电流值的条件。
可选的，对于Boost电路所接的并联无压差光伏组串，所述逆变器至少一次控制其中一个所述优化器改变输出电压之前，还包括：
所述逆变器判断Boost电路所接并联光伏组串中各所述优化器的电气状态是否一致；
若各所述电气状态一致，则判定相应并联光伏组串为所述并联无压差光伏组串；
若各所述电气状态并不一致，则所述逆变器先确定输出电流大于预设正电流值或小于预设负电流值的所述优化器，属于同一光伏组串；再在相应并联光伏组串中光伏组串数量大于2的情况下，判定其中其他光伏组串为所述并联无压差光伏组串。
可选的，若所述逆变器已向各所述优化器设置所述输出电流限制值，则：
以输出电流为正的所述输出电流限制值，代替输出电流大于所述预设正电流值的条件；
并以输出电流为负的所述输出电流限制值，代替输出电流小于所述预设负电流值的条件。
可选的，在所述逆变器判断Boost电路所接并联光伏组串中各所述优化器的电气状态是否一致之前，还包括：
所述逆变器判断是否已区分各Boost电路所接的所述优化器；
若已区分各Boost电路所接的所述优化器，则执行所述逆变器判断Boost电路所接并联光伏组串中各所述优化器的电气状态是否一致的步骤；
若未区分各Boost电路所接的所述优化器，则所述逆变器按照预设规则控制相应Boost电路输入端分别保持预设时长的短路状态，并根据各次短路状态下全部所述优化器的输出电参数，确定各Boost电路所接的所述优化器；再执行所述逆变器判断Boost电路所接并联光伏组串中各所述优化器的电气状态是否一致的步骤。
可选的，所述输出电参数，包括：输出电压，和/或，输出电流；
所述逆变器根据各次短路状态下全部所述优化器的输出电参数，确定各Boost电路所接的所述优化器，包括：
各次短路状态下，对于输出电压为零和/或输出电流大于预设电流值或为所述输出电流限制值的各所述优化器，所述逆变器确定其连接至处于输入端短路状态的Boost电路；对于输出电压不为零和/或输出电流为零的各所述优化器，所述逆变器确定其不连接处于输入端短路状态的Boost电路。
可选的，所述逆变器按照预设规则控制相应Boost电路输入端分别保持预设时长的短路状态，包括：
所述逆变器逐一控制各Boost电路输入端分别保持预设时长的短路状态；或者，
所述逆变器对全部Boost电路进行逐次分组，每次控制当前分组中的部分Boost电路输入端保持预设时长的短路状态，并根据Boost电路输入端的不同状态对当前分组再次进行分组，直至当前分组中仅包括一个Boost电路。
本申请第二方面还提供了一种光伏系统，包括：逆变器和至少一个光伏组串；
所述光伏组串的两端之间设置有一个或至少两个输出端串联连接的优化器，所述优化器的输入端连接至少一个光伏组件；
所述逆变器的直流母线前级设置有至少一个Boost电路，且各Boost电路的输入端分别用于连接至少一个相应的光伏组串；
所述逆变器中的控制器，作为主节点与各所述优化器通信，并用于执行如上述第一方面任一种所述的光伏系统中并联光伏组串的优化器定位方法。
可选的，各Boost电路均独立于所述逆变器；或者，
各Boost电路均集成于所述逆变器中，各Boost电路的输出端通过所述直流母线连接至所述逆变器中逆变电路的直流侧。
可选的，所述Boost电路的输入端，分别连接所述逆变器直流侧的：一路连接端口，或者，至少两路并联连接的所述连接端口；
所述连接端口连接一个所述光伏组串，或者，所述连接端口通过汇流端子并联连接至少两个所述光伏组串。
本申请提供的光伏系统中并联光伏组串的优化器定位方法，首先由逆变器向各光伏组串中的优化器设置输出电压限制值和/或输出电流限制值，并控制各优化器启动；然后，对于Boost电路所接的并联无压差光伏组串，逆变器将至少一次控制其中一个优化器改变输出电压，主动为该并联无压差光伏组串制造组串间压差，进而构建并联连接的长串和短串，以形成环流；由于环流会导致长串和短串内优化器的电气状态有所不同，所以可以以各优化器的电气状态区分其各自所属的光伏组串，进而自动实现了对于Boost电路所接不同光伏组串之间的优化器区分，也即实现了对于优化器的组串级定位。
附图说明
为了更清楚地说明本发明实施例或现有技术中的技术方案，下面将对实施例或现有技术描述中要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本发明的实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据提供的附图获得其他的附图。
图1至图3分别为本申请实施例提供的光伏系统中并联光伏组串的优化器定位方法的三种流程图；
图4为本申请实施例提供的光伏系统的结构示意图；
图5为本申请实施例提供的光伏组串的结构示意图；
图6为本申请实施例提供的光伏系统的具体结构示意。
具体实施方式
下面将结合本发明实施例中的附图，对本发明实施例中的技术方案进行清 楚、完整地描述，显然，所描述的实施例仅仅是本发明一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。
在本申请中，术语“包括”、“包含”或者其任何其他变体意在涵盖非排他性的包含，从而使得包括一系列要素的过程、方法、物品或者设备不仅包括那些要素，而且还包括没有明确列出的其他要素，或者是还包括为这种过程、方法、物品或者设备所固有的要素。在没有更多限制的情况下，由语句“包括一个……”限定的要素，并不排除在包括要素的过程、方法、物品或者设备中还存在另外的相同要素。
本申请提供一种光伏系统的优化器定位方法，以自动实现对于Boost电路所接不同光伏组串之间的优化器区分。
该光伏系统中包括：逆变器，及，该逆变器直流母线前级各Boost电路所接的相应光伏组串；并且，至少一个Boost电路连接有至少两个并联的光伏组串。参见图1，该光伏系统中并联光伏组串的优化器定位方法，包括：
S101、逆变器向各光伏组串中的优化器设置输出电压限制值和/或输出电流限制值。
实际应用中，可以设置该输出电压限制值Ulmt＝10V，并设置该输出电流限制值Ilmt＝2A，但并不仅限于此，两者的取值可根据实际需要进行设置，均在本申请的保护范围内。
S102、逆变器控制各优化器启动。
该逆变器控制各优化器启动的过程，具体可以是：逆变器向各优化器发送激活指令，使各优化器进入工作模式，通过软启动提高输出电压。若步骤S101中已经设置了输出电压限制值Ulmt，则各优化器输出电压的提高最终会使其达到该输出电压限制值Ulmt。若步骤S101中未设置该输出电压限制值Ulmt，则各优化器输出电压的提高最终可以使其达到额定输出电压。
实际应用中，当Boost电路的输入端连接有至少两个并联连接且电压相同的光伏组串时，可以称这些光伏组串为并联无压差光伏组串；对于Boost电路所接的并联无压差光伏组串，需要执行步骤S103。当至少两个Boost电路连 接有并联无压差光伏组串时，需要分别对其所接并联无压差光伏组串执行步骤S103。
S103、逆变器至少一次控制其中一个优化器改变输出电压，并以各优化器的电气状态区分其各自所属的光伏组串。
实际应用中，控制优化器改变输出电压，可以是通过直接控制相应优化器主动旁路来实现，这时相应优化器的输出电压为零，其所属光伏组串的电压会降低。
或者，当步骤S101中设置了该输出电压限制值Ulmt，步骤S102使各优化器的输出电压均达到该输出电压限制值Ulmt时：步骤S103中的控制优化器改变输出电压，还可以是通过提高相应优化器的输出电压限制值Ulmt来实现，这时相应优化器的输出电压也会随之升高；又或者，步骤S103中的控制优化器改变输出电压，也可以是通过降低相应优化器的输出电压限制值Ulmt来实现，这时相应优化器的输出电压也会随之降低，比如降低至零与S101中的输出电压限制值Ulmt之间。
对于并联有至少两个电压相同的光伏组串的Boost电路，逆变器控制其中任一优化器主动旁路或降低输出电压限制值Ulmt后，会导致其所属光伏组串的电压降低，等效于该光伏组串变短，所以可以称之为短串；而其他光伏组串保持原本的电压，等效于保持原本的长度，相对于该短串而言可以称之为长串。另外，当逆变器控制其中任一优化器提高输出电压限制值Ulmt后，会导致其成为长串；而其他光伏组串成为短串。
不论采用上述何种方式改变任一优化器的输出电压，都会导致相应并联无压差光伏组串中出现长串和短串；这时，并联的长短串之间会形成环流，长串向短串灌入电流；若步骤S101中未设置该输出电流限制值Ilmt，则灌入的电流值会根据长短串之间的压差来决定；若步骤S101中已经设置了该输出电流限制值Ilmt，则该灌入的电流值不会超过该输出电流限制值Ilmt，以两个电压相同的光伏组串并联为例进行说明，此时，长串中各优化器的输出电流均为该输出电流限制值Ilmt，而短串中各优化器的输出电流均为－Ilmt，即负的输出电流限制值；同时，长串中的各优化器均处于正向输出状态，而短串中的各优化器均处于反向输入状态。另外，由于长短串并联，所以，在步骤S101中未 设置该输出电压限制值Ulmt的情况下，短串中各优化器的输出电压均为其额定输出电压，而长串中各优化器输出端分担的电压会低于其额定输出电压但大于0V；而在步骤S101中设置了该输出电压限制值Ulmt的情况下，短串中各优化器的输出电压均为该输出电压限制值Ulmt，而长串中各优化器输出端分担的电压会低于该输出电压限制值Ulmt但同样会大于0V。
基于各优化器的输出电压、输出电流及工作状态中的至少一种，作为相应优化器的电气状态，至少可以识别出当前状态下电压被改变的光伏组串中的各优化器；以步骤S101中同时设置了输出电压限制值Ulmt和输出电流限制值Ilmt为例进行说明：若相应光伏组串被改变为短串，则其各优化器的具体表现为：输出电压为Ulmt、输出电流为－Ilmt以及工作状态为反向输入状态，这些优化器与当前被减小输出电压的优化器属于同一光伏组串；若相应光伏组串被改变为长串，则其各优化器的具体表现为：输出电压小于Ulmt、输出电流为Ilmt以及工作状态为正向输出状态，这些优化器与当前被增大输出电压的优化器属于同一光伏组串。若仅两个光伏组串并联，则可以确定剩余各优化器属于另一光伏组串。若存在更多个光伏组串并联，则多次进行上述改变输出电压的控制，即可识别出多个电压被改变的光伏组串，直至全部优化器均被识别出其所属光伏组串，即可实现对于全部并联无压差光伏组串的优化器定位。
本实施例提供的该光伏系统中并联光伏组串的优化器定位方法，逆变器每次控制其中一个优化器改变输出电压，均可以主动为相应的光伏组串制造组串间压差，进而构建并联连接的长串和短串，以形成环流；由于环流会导致长串和短串内优化器的电气状态有所不同，所以可以以各优化器的电气状态区分其各自所属的光伏组串，进而自动实现了对于Boost电路所接不同光伏组串之间的优化器区分，也即实现了对于优化器的组串级定位，有利于逆变器对每个光伏组串的差异性控制。
在上一实施例的基础之上，该光伏系统中并联光伏组串的优化器定位方法，其步骤S103中，逆变器至少一次控制其中一个优化器改变输出电压，并以各优化器的电气状态区分其各自所属的光伏组串，具体包括：逆变器从未确定所属光伏组串的优化器中，控制其中任一优化器改变输出电压；而且，逆变 器在每次控制相应优化器改变输出电压后，均检测各优化器的电气状态，并根据各电气状态，确定与该改变输出电压的优化器处于同一光伏组串的各优化器，并确定其他优化器属于其他光伏组串，直至逆变器实现对于相应各优化器所属光伏组串的区分。
如上一实施例所述，该电气状态包括：输出电压、输出电流及工作状态中的至少一种；此时：
若步骤S103中改变输出电压的方向为减小，则上述与改变输出电压的优化器处于同一光伏组串的各优化器，将会是满足以下至少一种条件的优化器：输出电压大于预设电压值、输出电流小于预设负电流值及工作状态为反向输入状态。
若步骤S103中改变输出电压的方向为增大，则与改变输出电压的优化器处于同一光伏组串的各优化器，具体是满足以下至少一种条件的优化器：输出电压小于预设电压值、输出电流大于预设正电流值及工作状态为正向输出状态。
上述用于判断比较的各种预设值，均可以根据实际情况来定，只要能够表征并联光伏组串中出现环流即可。需要说明的是，若步骤S101中设置了该输出电压限制值Ulmt，则上述两种输出电压改变方向下关于输出电压大于预设电压值的条件，将可以替换为：输出电压为该输出电压限制值Ulmt；而输出电压小于预设电压值的条件，将可以替换为：输出电压小于该输出电压限制值Ulmt。若步骤S101中设置了该输出电流限制值Ilmt，则上述两种输出电压改变方向下关于输出电流小于预设负电流值的条件，将可以替换为：输出电流为负的输出电流限制值Ilmt；而输出电流大于预设正电流值的条件，将可以替换为：输出电流为正的输出电流限制值Ilmt。
以步骤S101中同时设置了输出电压限制值Ulmt和输出电流限制值Ilmt，且改变输出电压的方向为减小为例进行说明：对于Boost电路所接的至少两个并联且电压相同的光伏组串，逆变器控制其中任一优化器减小输出电压后，并联的长短串之间会形成环流，此时，短串中各优化器的输出电流均为－Ilmt(即负的输出电流限制值)；在两个光伏组串并联时，仅存在一个长串，则，长串中各优化器的输出电流均为该输出电流限制值Ilmt；而三个光伏组串并联时， 将存在两个长串，则长串中各优化器的输出电流均为Ilmt/2；以此类推，n个光伏组串并联时，将存在n－1个长串，则长串中各优化器的输出电流均为Ilmt/(n－1)。但不论几个光伏组串并联，都将会是：长串中的各优化器均处于正向输出状态，而短串中的各优化器均处于反向输入状态。另外，短串中各优化器的输出电压均为该输出电压限制值Ulmt，而长串中各优化器的输出电压会在0到Ulmt之间。
第一次控制任一优化器减小输出电压后，基于各优化器的电气状态，可以识别出当前状态下属于短串中的各优化器，确定这些优化器与当前被减小输出电压的优化器属于同一光伏组串。此时，若仅有两个光伏组串并联，则输出电压在0到Ulmt之间、输出电流为Ilmt、工作状态为正向输出状态的各优化器，属于上述长串，也即另一光伏组串。改变输出电压的方向为增大的原理可以以此类推，不再赘述。
需要说明的是，若存在n个光伏组串并联，n为大于2的整数，则第一次控制任一优化器改变输出电压后，剩余的优化器，比如第一次改变输出电压的方向为减小时，得到的输出电压在0到Ulmt之间、输出电流为Ilmt/(n－1)、工作状态为正向输出状态的各优化器，可以确定其属于另外n－1个光伏组串，尚不能确定其具体所属的光伏组串；这些光伏组串虽然当前长度相同，但再一次控制其中任一优化器改变输出电压后，即可再一次构建得到新的短串和长串，再通过一次上述电气状态识别的过程，可以再一次区分出电压被改变的光伏组串中的优化器；重复上述过程，直至全部光伏组串中的优化器均被定位，即可实现对于全部并联无压差光伏组串的优化器定位。
在上述实施例的基础之上，需要说明的是，在系统安装之后，也有可能出现初始状态原本就存在不等长光伏组串并联的情况，这时，在各优化器启动之后，即可对各优化器的电气状态进行一次判断，若并联光伏组串中各优化器的电气状态不一致，则可以直接识别出一次长度不同于其他光伏组串的短串或长串；若两个光伏组串并联，则无需再执行上述改变输出电压的控制过程；若更多个光伏组串并联，也可以先识别出一路本身就长度特殊的光伏组串，进而减少一次后续需要执行的上述改变输出电压的控制过程。
也即，在上述实施例的基础之上，本实施例提供的该光伏系统中并联光伏组串的优化器定位方法，如图2所示，其对于Boost电路所接的并联光伏组串，在执行步骤S103之前，还包括：
S201、逆变器判断各优化器的电气状态是否一致。
若各电气状态一致，则判定相应并联光伏组串为并联无压差光伏组串，直接执行步骤S103即可。若各电气状态并不一致，则先执行步骤S202，再在相应并联光伏组串中光伏组串数量大于2的情况下，判定其中其他光伏组串为并联无压差光伏组串，并执行步骤S103。
S202、逆变器确定输出电流大于预设正电流值或小于预设负电流值的优化器，属于同一光伏组串。
若步骤S101中已经设置了该输出电流限制值Ilmt，则该步骤S202中，输出电流大于预设正电流值的条件，可以替换为输出电流为正的输出电流限制值；而输出电流小于预设负电流值的条件，可以替换为输出电流为负的输出电流限制值。
仍以步骤S101中同时设置了输出电压限制值Ulmt和输出电流限制值Ilmt为例进行说明：
假设某一Boost电路的输入端并联连接有三个光伏组串，其中两个光伏组串的长度一样，均长于另一光伏组串，也即该输入端并联连接有两个长串和一个短串；则各优化器启动之后，两个长串向短串灌入电流，短串中优化器的电气状态表现为：输出电压为Ulmt、输出电流为－Ilmt、工作状态为反向输入状态，两个长串中优化器的电气状态表现为：输出电压在0到Ulmt之间、输出电流为Ilmt/2、工作状态为正向输出状态；进而可以识别出短串中的各优化器，再对两个长串执行步骤S103。
假设某一Boost电路的输入端并联连接有三个光伏组串，其中两个光伏组串的长度一样，均短于另一光伏组串，也即该输入端并联连接有两个短串和一个长串；则各优化器启动之后，长串向两个短串灌入电流，长串中优化器的电气状态表现为：输出电压在0到Ulmt之间、输出电流为Ilmt、工作状态为正向输出状态，两个短串中优化器的电气状态表现为：输出电压为Ulmt、输出 电流为－Ilmt/2、工作状态为反向输入状态；进而可以识别出长串中的各优化器，再对两个短串执行步骤S103。
更多个光伏组串并联的情况，可以依次类推，此处不再一一赘述。
本实施例通过步骤S201和S202，可以直接确定一个长度特殊的光伏组串中的各优化器，使得优化器的组串级定位过程更为简单。
实际应用中，如果在系统安装后通过人工录入，已经实现了各优化器与逆变器各Boost电路之间的相互对应，则通过上述任一实施例即可实现对于全部优化器的组串级定位；但是，若系统安装后并未进行上述人工录入过程，或者，考虑人工手动录入过程存在效率低且容易出错的问题，则可以通过逆变器先区分各Boost电路所接的光伏组串，也即，该光伏系统中并联光伏组串的优化器定位方法，在上述实施例的基础之上，还可以如图3(以在图2的基础上为例)所示，其在步骤S102之后，还包括：
S301、逆变器判断是否已区分各Boost电路所接的优化器。
若已区分各Boost电路所接的优化器，则对Boost电路所接的并联光伏组串，执行步骤S201。
若未区分各Boost电路所接的优化器，则先执行步骤S302，再对Boost电路所接的并联光伏组串，执行步骤S201。
S302、逆变器按照预设规则控制相应Boost电路输入端分别保持预设时长的短路状态，并根据各次短路状态下全部优化器的输出电参数，确定各Boost电路所接的优化器。
该步骤S302中，逆变器按照预设规则控制相应Boost电路输入端分别保持预设时长的短路状态，具体可以是：逆变器逐一控制各Boost电路输入端分别保持预设时长的短路状态；或者，也可以是：逆变器对全部Boost电路进行逐次分组，每次控制当前分组中的部分Boost电路输入端保持预设时长的短路状态，并根据Boost电路输入端的不同状态对当前分组再次进行分组，直至当前分组中仅包括一个Boost电路。
实际应用中，该输出电参数，可以包括：输出电压，和/或，输出电流；该步骤S302中，逆变器根据各次短路状态下全部优化器的输出电参数，确定 各Boost电路所接的优化器，具体可以包括：各次短路状态下，对于输出电压为零和/或输出电流大于预设电流值或为输出电流限制值的各优化器，逆变器确定其连接至处于输入端短路状态的Boost电路；对于输出电压不为零和/或输出电流为零的各优化器，逆变器确定其不连接处于输入端短路状态的Boost电路。
若步骤S101中未设置该输出电流限制值Ilmt，则输入端短路状态的Boost电路，其所接光伏组串中各优化器的输出电流会达到短路电流，通过大于一个预设电流值即可识别；而若步骤S101中已经设置了该输出电流限制值Ilmt，则输入端短路状态的Boost电路，其所接光伏组串中各优化器的输出电流只能达到该输出电流限制值Ilmt。
考虑一种逆变器需要对各优化器所接的Boost电路和组串级定位进行全自动确定的场景，其在上电后，首先向各优化器发送搜寻指令，使各优化器分别将自身的序列号发送至逆变器；然后通过步骤S101向优化器设置输出电压限制值Ulmt和输出电流限制值Ilmt，再通过步骤S102控制各优化器启动并将各自的输出电压升高到该输出电压限制值Ulmt；而后，执行步骤S301和S302，确定各优化器所接的Boost电路；此时，再对Boost电路所接的并联光伏组串，先通过步骤S201和S202，识别出一路长度特殊的光伏组串；如有需要，可以再对相应Boost电路所接的并联无压差光伏组串分别执行步骤S103，进而通过这些光伏组串中各优化器的电气状态之间的不同，将这些优化器按照其所属光伏组串进行分类，定位出属于同一光伏组串的所有优化器。上述过程可以实现对所有优化器的组串级自动组网和定位，可以避免人工手动录入每个优化器信息的过程，提高了组网的效率并降低了出错的概率。
本申请另一实施例还提供了一种光伏系统，如图4所示，包括：逆变器200和至少一个光伏组串100；其中：
逆变器200的直流母线前级设置有至少一个Boost电路201，且各Boost电路201的输入端分别用于连接有至少一个相应的光伏组串100。
值得说明的是，如图4所示，各Boost电路201可以均集成于该逆变器200中，各Boost电路201的输出端通过直流母线连接至逆变器200中逆变电路202 的直流侧。实际应用中，各Boost电路201也可以均独立于该逆变器200(未进行图示)，视其具体应用环境而定即可，均在本申请的保护范围内。
该逆变器200根据不同的型号，与相应适用的单相或三相电网相连。
如图5所示，光伏组串100的两端之间设置有一个或至少两个输出端串联连接的优化器102，优化器102的输入端连接至少一个光伏组件101。
逆变器200中的控制器，作为主节点与各优化器102通信，并用于执行上述任一实施例所述的光伏系统中并联光伏组串的优化器定位方法。该优化器定位方法的具体执行过程和原理，参见上述实施例即可，此处不再一一赘述。
如图4和图6中所示，逆变器200的主电路中包括：逆变电路202和至少一个Boost电路201时，该逆变器200内部可以包含m个Boost电路(如图6中所示的Boost 1、…Boost x、…Boost m)，m为大于或等于1的正整数。
实际应用中，各Boost电路201的输入端，可以仅连接逆变器200直流侧的一路连接端口，或者，也可以连接逆变器200直流侧的至少两路并联连接的连接端口；各Boost电路201输入端的设置可以相同，也可以不同，视其具体应用环境而定即可，均在本申请的保护范围内。各Boost电路201输入端所接的连接端口，可以连接一个光伏组串100，或者，也可以通过汇流端子并联连接至少两个光伏组串100；视其具体应用环境而定即可，均在本申请的保护范围内。
具体的，每路Boost电路201具有一个输入端，该输入端也可以称之为一个MPPT端口。每路MPPT端口可以在逆变器200内部分成两路并联形式的连接端口，该连接接口可以称之为PV端口，当然，每路MPPT端口也可以直接成为一路PV端口。每路PV端口可以接一个光伏组串100，或者通过汇流端子，连接两路并联的光伏组串100。一个系统中可以接入不少于2个的光伏组串100。
参见图5和图6，假设每个光伏组串100包括n个光伏模块(如图中所示的光伏模块1至光伏模块n)，n为大于或等于2的正整数，且当逆变器200为单相机时，n小于或等于25；当逆变器200为三相机时，n小于或等于50。由于该系统为全部安装优化器102的系统，所以每个光伏模块必须包括一个光伏单元和一个优化器102。光伏单元包括至少一个光伏组件101，光伏单元连 接到优化器102的输入端，光伏组串100中的所有优化器102输出端相互串联，即优化器102正输出端连接到上一个优化器102负输出端，优化器102负输出端连接到下一个优化器102正输出端，最终连接到逆变器200的一个PV端口上。
需要说明的是，连接到同一个系统中的不同光伏组串100中光伏模块数量允许不一样，接入不同MPPT端口的光伏组串100的串并联方式允许不一致，光伏单元的功率允许不一致。
实际应用中，该逆变器200中，每个Boost电路的MPPT端口上可以不接光伏组串100，也可以连接1至3个光伏组串100，但至少存在一个Boost电路的MPPT端口上连接有至少2个光伏组串100；比如，三相户用逆变器，其每路MPPT端口分别连接2路光伏组串100；实际应用中，各MPPT端口所接的并联光伏组串，可以是2个光伏组串100的并联，也可以是2个以上光伏组串100的并联，视其具体应用环境而定，均在本申请的保护范围内。
图6所示为其中一种全部安装优化器102的光伏系统中的并联光伏组串结构，其由2个光伏组串(如图中所示的光伏组串1和光伏组串2)100并联形成，其中光伏组串1中包含n1个光伏模块，光伏组串2中包含n2个光伏模块，n1与n2可以相同，也可以不同；如果n1与n2相同，则可以称这对并联光伏组串为相同并联串；如果n1与n2不同，则可以称这对并联光伏组串为差异并联串。
接下来对该优化器定位方法的主要步骤进行说明，具体如下：
(1)该优化器定位方法的执行具有一定的前提条件。
逆变器的控制器，作为主节点通过上述实施例中所述的步骤S302实现自动组网，或者通过人工录入的信息，已经可以区分出连接在同一MPPT端口的并联光伏组串的所有优化器信息，但是没有区分出每个优化器所位于的具体光伏组串。
(2)该优化器定位方法中，首先对各优化器的输出电参数进行设置。
参见上述实施例中所述的步骤S101，逆变器主节点会向每个优化器发送设置指令，其中包括输出电压限制值Ulmt，以及输出电流限制值Ilmt，二者 可根据实际需要进行设置，比如可以采用Ulmt＝10V，Ilmt＝2A，但并不仅限于此。此过程中，各优化器均处于输出1V的安全模式。
(3)然后即可执行该优化器定位方法中对各优化器的启动控制。
参见上述实施例中所述的步骤S102，逆变器主节点会广播发送激活指令，优化器在接收到该激活指令后就会从安全模式转入工作模式，开始软启动，逐渐提高输出电压，直到到达输出电压限制值Ulmt。然后逆变器主节点会收集所有优化器的电压电流状态。
(4)再执行该优化器定位方法中对各优化器电气状态的判断。
参见上述实施例中所述的步骤S201和S202；步骤S201中，逆变器主节点可以根据优化器启动后的电压电流状态进行判断：如果所有的优化器都是输出电压为Ulmt、输出电流为0A，则说明没有形成环流，可以判定该并联光伏组串为相同并联串(也即上述并联无压差光伏组串)；如果其中一部分优化器的输出电压介于Ulmt和0V之间、输出电流为Ilmt，而另一部分优化器的输出电压为Ulmt、输出电流为-Ilmt，则说明并联光伏组串的长度不相同，即图6中所示并联光伏组串中的优化器个数不同，可以判定该并联光伏组串为差异并联串。
以图6所示结构为例，如果被判定为差异并联串，则所有输出电压介于Ulmt和0V之间、输出电流为Ilmt的优化器，可以被定位为同一光伏组串；而所有输出电压为Ulmt、输出电流为－Ilmt的优化器，可以被定位为另一光伏组串；定位完成，可以结束。但是，如果被判定为相同并联串，则需要进行第(5)步。
(5)对并联光伏组串中未确定所属光伏组串的任一优化器，也即对上述并联无压差光伏组串的任一优化器，进行改变输出电压控制。
参见上述实施例中所述的步骤S103，以主动旁路控制为例进行说明，逆变器主节点可以任意选择其中一个优化器，向其发送主动旁路指令。该优化器在接收到主动旁路指令之后，会从工作模式转变成主动旁路模式，其输出被旁路，没有输出电压，使得图6所示结构中原本为相同并联串的两个光伏组串形成差异，进而出现环流。此时逆变器主节点会再收集所有优化器的电压电流状态。
然后，逆变器主节点会根据优化器启动后的电压电流状态进行判断：所有输出电压介于Ulmt和0V之间、输出电流为Ilmt的优化器，可以被定位为同一光伏组串；而所有输出电压为Ulmt、输出电流为-Ilmt的优化器，以及被主动旁路的优化器，可以被定位为另一光伏组串。此时，定位完成，可以结束。
通过上述过程，可以在已知各Boost电路的MPPT端口所连接的所有优化器信息的情况下，针对并联光伏组串，自动区分优化器所属的光伏组串，实现优化器的组串级定位。
本说明书中的各个实施例之间相同相似的部分互相参见即可，每个实施例重点说明的都是与其他实施例的不同之处。尤其，对于系统或系统实施例而言，由于其基本相似于方法实施例，所以描述得比较简单，相关之处参见方法实施例的部分说明即可。以上所描述的系统及系统实施例仅仅是示意性的，其中所述作为分离部件说明的单元可以是或者也可以不是物理上分开的，作为单元显示的部件可以是或者也可以不是物理单元，即可以位于一个地方，或者也可以分布到多个网络单元上。可以根据实际的需要选择其中的部分或者全部模块来实现本实施例方案的目的。本领域普通技术人员在不付出创造性劳动的情况下，即可以理解并实施。
专业人员还可以进一步意识到，结合本文中所公开的实施例描述的各示例的单元及算法步骤，能够以电子硬件、计算机软件或者二者的结合来实现，为了清楚地说明硬件和软件的可互换性，在上述说明中已经按照功能一般性地描述了各示例的组成及步骤。这些功能究竟以硬件还是软件方式来执行，取决于技术方案的特定应用和设计约束条件。专业技术人员可以对每个特定的应用来使用不同方法来实现所描述的功能，但是这种实现不应认为超出本发明的范围。
对所公开的实施例的上述说明，本说明书中各实施例中记载的特征可以相互替换或者组合，使本领域专业技术人员能够实现或使用本发明。对这些实施例的多种修改对本领域的专业技术人员来说将是显而易见的，本文中所定义的一般原理可以在不脱离本发明的精神或范围的情况下，在其它实施例中实现。因此，本发明将不会被限制于本文所示的这些实施例，而是要符合与本文所公开的原理和新颖特点相一致的最宽的范围。

Claims (13)

  1. 一种光伏系统中并联光伏组串的优化器定位方法，其特征在于，光伏系统中包括：逆变器及其直流母线前级各Boost电路所接的相应光伏组串；所述优化器定位方法包括：
    所述逆变器向各光伏组串中的优化器设置输出电压限制值和/或输出电流限制值；
    所述逆变器控制各所述优化器启动；
    对于Boost电路所接的并联无压差光伏组串，所述逆变器至少一次控制其中一个所述优化器改变输出电压，并以各所述优化器的电气状态区分其各自所属的光伏组串。
  2. 根据权利要求1所述的光伏系统中并联光伏组串的优化器定位方法，其特征在于，改变输出电压，包括：主动旁路；或者，
    若所述逆变器已向各所述优化器设置所述输出电压限制值，则在所述逆变器控制各所述优化器启动之后，还包括：所述逆变器控制各所述优化器的输出电压达到所述输出电压限制值；且，改变输出电压，包括：提高或降低所述输出电压限制值。
  3. 根据权利要求1所述的光伏系统中并联光伏组串的优化器定位方法，其特征在于，所述逆变器至少一次控制其中一个所述优化器改变输出电压，并以各所述优化器的电气状态区分其各自所属的光伏组串，包括：
    所述逆变器从未确定所属光伏组串的所述优化器中，控制其中任一所述优化器改变输出电压；
    所述逆变器在每次控制相应所述优化器改变输出电压后，检测各所述优化器的所述电气状态，并根据各所述电气状态，确定与改变输出电压的所述优化器处于同一光伏组串的各所述优化器，并确定其他所述优化器属于其他光伏组串，直至所述逆变器实现对于相应各所述优化器所属光伏组串的区分。
  4. 根据权利要求3所述的光伏系统中并联光伏组串的优化器定位方法，其特征在于，所述电气状态包括：输出电压、输出电流及工作状态中的至少一种；
    若改变输出电压的方向为减小，则与改变输出电压的所述优化器处于同一光伏组串的各所述优化器，包括：
    满足输出电压大于预设电压值、输出电流小于预设负电流值及工作状态为反向输入状态中至少一种条件的所述优化器；
    若改变输出电压的方向为增大，则与改变输出电压的所述优化器处于同一光伏组串的各所述优化器，包括：
    满足输出电压小于所述预设电压值、输出电流大于预设正电流值及工作状态为正向输出状态中至少一种条件的所述优化器。
  5. 根据权利要求4所述的光伏系统中并联光伏组串的优化器定位方法，其特征在于，若所述逆变器已向各所述优化器设置所述输出电压限制值，则以输出电压为所述输出电压限制值，代替输出电压大于所述预设电压值的条件；并以输出电压小于所述输出电压限制值，代替输出电压小于所述预设电压值的条件；
    若所述逆变器已向各所述优化器设置所述输出电流限制值，则以输出电流为负的所述输出电流限制值，代替输出电流小于所述预设负电流值的条件；并以输出电流为正的所述输出电流限制值，代替输出电流大于所述预设正电流值的条件。
  6. 根据权利要求1至5任一项所述的光伏系统中并联光伏组串的优化器定位方法，其特征在于，对于Boost电路所接的并联无压差光伏组串，所述逆变器至少一次控制其中一个所述优化器改变输出电压之前，还包括：
    所述逆变器判断Boost电路所接并联光伏组串中各所述优化器的电气状态是否一致；
    若各所述电气状态一致，则判定相应并联光伏组串为所述并联无压差光伏组串；
    若各所述电气状态并不一致，则所述逆变器先确定输出电流大于预设正电流值或小于预设负电流值的所述优化器，属于同一光伏组串；再在相应并联光伏组串中光伏组串数量大于2的情况下，判定其中其他光伏组串为所述并联无压差光伏组串。
  7. 根据权利要求6所述的光伏系统中并联光伏组串的优化器定位方法，其特征在于，若所述逆变器已向各所述优化器设置所述输出电流限制值，则：
    以输出电流为正的所述输出电流限制值，代替输出电流大于所述预设正电流值的条件；
    并以输出电流为负的所述输出电流限制值，代替输出电流小于所述预设负电流值的条件。
  8. 根据权利要求6所述的光伏系统中并联光伏组串的优化器定位方法，其特征在于，在所述逆变器判断Boost电路所接并联光伏组串中各所述优化器的电气状态是否一致之前，还包括：
    所述逆变器判断是否已区分各Boost电路所接的所述优化器；
    若已区分各Boost电路所接的所述优化器，则执行所述逆变器判断Boost电路所接并联光伏组串中各所述优化器的电气状态是否一致的步骤；
    若未区分各Boost电路所接的所述优化器，则所述逆变器按照预设规则控制相应Boost电路输入端分别保持预设时长的短路状态，并根据各次短路状态下全部所述优化器的输出电参数，确定各Boost电路所接的所述优化器；再执行所述逆变器判断Boost电路所接并联光伏组串中各所述优化器的电气状态是否一致的步骤。
  9. 根据权利要求8所述的光伏系统中并联光伏组串的优化器定位方法，其特征在于，所述输出电参数，包括：输出电压，和/或，输出电流；
    所述逆变器根据各次短路状态下全部所述优化器的输出电参数，确定各Boost电路所接的所述优化器，包括：
    各次短路状态下，对于输出电压为零和/或输出电流大于预设电流值或为所述输出电流限制值的各所述优化器，所述逆变器确定其连接至处于输入端短路状态的Boost电路；对于输出电压不为零和/或输出电流为零的各所述优化器，所述逆变器确定其不连接处于输入端短路状态的Boost电路。
  10. 根据权利要求8所述的光伏系统中并联光伏组串的优化器定位方法，其特征在于，所述逆变器按照预设规则控制相应Boost电路输入端分别保持预设时长的短路状态，包括：
    所述逆变器逐一控制各Boost电路输入端分别保持预设时长的短路状态；或者，
    所述逆变器对全部Boost电路进行逐次分组，每次控制当前分组中的部分Boost电路输入端保持预设时长的短路状态，并根据Boost电路输入端的不同状态对当前分组再次进行分组，直至当前分组中仅包括一个Boost电路。
  11. 一种光伏系统，其特征在于，包括：逆变器和至少一个光伏组串；
    所述光伏组串的两端之间设置有一个或至少两个输出端串联连接的优化器，所述优化器的输入端连接至少一个光伏组件；
    所述逆变器的直流母线前级设置有至少一个Boost电路，且各Boost电路的输入端分别用于连接至少一个相应的光伏组串；
    所述逆变器中的控制器，作为主节点与各所述优化器通信，并用于执行如权利要求1至10任一项所述的光伏系统中并联光伏组串的优化器定位方法。
  12. 根据权利要求11所述的光伏系统，其特征在于，各Boost电路均独立于所述逆变器；或者，
    各Boost电路均集成于所述逆变器中，各Boost电路的输出端通过所述直流母线连接至所述逆变器中逆变电路的直流侧。
  13. 根据权利要求11或12所述的光伏系统，其特征在于，所述Boost电路的输入端，分别连接所述逆变器直流侧的：一路连接端口，或者，至少两路并联连接的所述连接端口；
    所述连接端口连接一个所述光伏组串，或者，所述连接端口通过汇流端子并联连接至少两个所述光伏组串。
PCT/CN2022/140971 2022-06-17 2022-12-22 一种光伏系统及其优化器定位方法 WO2023240980A1 (zh)

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109713710A (zh) * 2017-10-26 2019-05-03 阳光电源股份有限公司 一种通信主机以及光伏发电系统
US20200343729A1 (en) * 2019-04-23 2020-10-29 Delta Electronics (Shanghai) Co., Ltd. Photovoltaic power generation system and method for controlling the same
CN114204588A (zh) * 2020-09-18 2022-03-18 广州中旭新能源有限公司 一种优化电压控制的方法和光伏发电系统
WO2022057944A1 (zh) * 2020-09-18 2022-03-24 深圳市中旭新能源有限公司 一种区域智能优化的光伏组件及其发电系统
CN114337541A (zh) * 2022-01-07 2022-04-12 阳光电源股份有限公司 一种光伏组件的iv扫描方法、光伏系统
CN114977298A (zh) * 2022-06-17 2022-08-30 阳光电源（上海）有限公司 一种光伏系统及其优化器定位方法

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109713710A (zh) * 2017-10-26 2019-05-03 阳光电源股份有限公司 一种通信主机以及光伏发电系统
US20200343729A1 (en) * 2019-04-23 2020-10-29 Delta Electronics (Shanghai) Co., Ltd. Photovoltaic power generation system and method for controlling the same
CN114204588A (zh) * 2020-09-18 2022-03-18 广州中旭新能源有限公司 一种优化电压控制的方法和光伏发电系统
WO2022057944A1 (zh) * 2020-09-18 2022-03-24 深圳市中旭新能源有限公司 一种区域智能优化的光伏组件及其发电系统
CN114337541A (zh) * 2022-01-07 2022-04-12 阳光电源股份有限公司 一种光伏组件的iv扫描方法、光伏系统
CN114977298A (zh) * 2022-06-17 2022-08-30 阳光电源（上海）有限公司 一种光伏系统及其优化器定位方法

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