WO2022166537A1 - 光伏系统及其供电电流控制方法 - Google Patents
光伏系统及其供电电流控制方法 Download PDFInfo
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- WO2022166537A1 WO2022166537A1 PCT/CN2022/071222 CN2022071222W WO2022166537A1 WO 2022166537 A1 WO2022166537 A1 WO 2022166537A1 CN 2022071222 W CN2022071222 W CN 2022071222W WO 2022166537 A1 WO2022166537 A1 WO 2022166537A1
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- power supply
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- 238000012937 correction Methods 0.000 claims description 134
- 238000006243 chemical reaction Methods 0.000 claims description 7
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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
- H02J1/00—Circuit arrangements for dc mains or dc distribution networks
- H02J1/10—Parallel operation of dc sources
- H02J1/12—Parallel operation of dc generators with converters, e.g. with mercury-arc rectifier
-
- 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
- H02S—GENERATION OF ELECTRIC POWER BY CONVERSION OF INFRARED RADIATION, VISIBLE LIGHT OR ULTRAVIOLET LIGHT, e.g. USING PHOTOVOLTAIC [PV] MODULES
- H02S40/00—Components or accessories in combination with PV modules, not provided for in groups H02S10/00 - H02S30/00
- H02S40/30—Electrical components
- H02S40/32—Electrical components comprising DC/AC inverter means associated with the PV module itself, e.g. AC modules
-
- 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
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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
Definitions
- the present application relates to the technical field of photovoltaic power generation, and in particular, to a photovoltaic system and a method for controlling power supply current thereof.
- a small power supply device such as a communication power supply
- multiple power supply devices are connected in parallel on the same bus, and a communication line is connected between the power supply devices.
- Each power supply device (including the master device and the slave device) collects its own power supply current, and the slave device uploads its own power supply current to the master device.
- the master device receives the power supply current of all slave devices connected in parallel on the same bus , calculate the average current reference value according to its own power supply current and the power supply current of all slave devices, and send it to each slave device.
- the master device and each slave device perform feedback adjustment of the power supply current according to the average current reference value. Due to the parameter differences between the parallel power supply devices in this solution, the reasonable load distribution among the parallel power supply devices cannot be guaranteed, which leads to excessive current sharing of some power supply devices and increased thermal stress, which ultimately affects the service life of the power supply devices.
- the present application provides a photovoltaic system and a power supply current control method thereof, which can ensure a reasonable distribution of loads among various power supply units, and has strong applicability.
- the present application provides a photovoltaic system
- the photovoltaic system includes a DC bus, at least two power supply units connected in parallel with the DC bus, and a DC/AC converter connected to the at least two power supply units through the DC bus, wherein, Each of the at least two power supply units includes a DC/DC converter, and the input end of the DC/DC converter is connected to the DC power supply.
- the DC/AC converter obtains the current output state parameters of the DC/DC converters in each power supply unit, and determines the current output state parameters of the DC/DC converters in each power supply unit.
- the reference output current value of the DC/DC converter in each power supply unit, and the current output power of the DC/DC converter in each power supply unit is adjusted according to the reference output current value of the DC/DC converter in each power supply unit.
- the DC/AC converter can adjust the current output power of each DC/DC converter according to the current actual power supply capability of each DC/DC converter in each power supply unit connected in parallel to the DC bus, to ensure that each DC/DC converter The output power is balanced between the /DC converters, and the applicability is strong.
- the DC/AC converter determines that the current output power of the photovoltaic system is greater than the system output power threshold.
- the current output state parameters of the DC/DC converters in each power supply unit include the current output power and current output capability of the DC/DC converters in each power supply unit.
- the DC/AC converter adjusts the current output power of the DC/DC converter in each power supply unit according to the current output power and current output capability of the DC/DC converter in each power supply unit to avoid a DC/DC conversion in the photovoltaic system
- the converter or part of the DC/DC converter works in the extreme working state.
- the DC/AC converter can adjust the current output power of each DC/DC converter according to the current actual output capability of each DC/DC converter connected in parallel with the DC bus, so as to ensure that each DC/DC converter is converted It can balance the output power between the converters, so as to avoid one DC/DC converter or some DC/DC converters in each DC/DC converter to work with the output power exceeding its current maximum output power, which has strong applicability.
- the current output state parameter of the DC/DC converter in each power supply unit includes the current maximum output power of the DC/DC converter in each power supply unit.
- the DC/AC converter determines, based on the current maximum output power of the DC/DC converter in each power supply unit, the current maximum output power of the DC/DC converter in each power supply unit and the current maximum output power of the DC/DC converter in at least two power supply units
- the current maximum output power ratio in the sum of the maximum output powers, and the reference output current value of the DC/DC converter in each power supply unit is determined based on the current maximum output power ratio.
- each DC/DC converter when the current output state parameter of each DC/DC converter includes the current maximum output power of each DC/DC converter, each DC/DC converter may be determined according to the current maximum output power of each DC/DC converter.
- the reference output current value of the DC/DC converter when the current output state parameter of each DC/DC converter includes the current maximum output power of each DC/DC converter, each DC/DC converter may be determined according to the current maximum output power of each DC/DC converter. The reference output current value of the DC/DC converter.
- the current output state parameters of the DC/DC converters in each power supply unit further include current equipment operating condition parameters of the DC/DC converters in each power supply unit; DC/AC The converter determines the current corrected output power of the DC/DC converter in each power supply unit based on the current equipment operating parameters and the current maximum output power of the DC/DC converter in each power supply unit, and based on the DC/DC converter in each power supply unit The current corrected output power of the DC/DC converter in each power supply unit is determined, and the current corrected output power ratio of the current corrected output power of the DC/DC converter in the at least two power supply units in the sum of the current corrected output power of the DC/DC converter in the at least two power supply units is determined, and The current corrected output power ratio is determined as the current maximum output power ratio.
- the DC/AC converter may determine the reference output current value of each DC/DC converter according to the current maximum output power of each DC/DC converter and current equipment operating condition parameters.
- the DC/AC converter obtains the respective power attenuation coefficients corresponding to the current equipment operating condition parameters of the DC/DC converter in each power supply unit, based on the DC/AC converter in each power supply unit.
- the current maximum output power of the DC converter and the power attenuation coefficient determine the current corrected output power of the DC/DC converter in each power supply unit.
- the power attenuation coefficient can be used to reduce the maximum output power of the DC/DC converters with excessive device temperature, excessive device current stress, or excessive device voltage stress, thereby extending the power consumption of each DC/DC converter. service life.
- the current device operating condition parameter includes at least one of current device temperature, current device current stress, or current device voltage stress.
- the current output state parameter of the DC/DC converter in each power supply unit further includes the current output current of the DC/DC converter in each power supply unit; the DC/AC converter Based on the current maximum output power ratio and the sum of current output currents of the DC/DC converters in the at least two power supply units, a reference output current value of the DC/DC converters in each power supply unit is determined.
- the current maximum output power ratio of each DC/DC converter can be compared with The product of the sum of the current output currents of all the DC/DC converters is determined as the reference output current value of each DC/DC converter, so as to realize the calculation of each DC/DC converter based on the current actual output capability of each DC/DC converter.
- the output current value is reasonably distributed.
- the present application provides a photovoltaic system, which includes a DC bus, at least two power supply units connected in parallel with the DC bus, and a system control unit in communication with the at least two power supply units.
- the system control unit obtains the current power supply state parameters of each power supply unit in the at least two power supply units, determines the reference power supply current value of each power supply unit according to the current power supply state parameter of each power supply unit, and supplies power to each power supply unit according to the reference power supply current value of each power supply unit The current supply power of the unit is adjusted.
- the system control unit can adjust the current power supply of each power supply unit according to the current actual power supply capability of each power supply unit connected in parallel with the DC bus, so as to ensure a reasonable load distribution among the power supply units, that is, to ensure that each power supply unit is properly distributed.
- the power supply between the units is balanced, and the applicability is strong.
- the system control unit determines that the current output power of the photovoltaic system is greater than the system output power threshold before acquiring the current power supply state parameters of each of the at least two power supply units.
- the system control unit when the current output power of the photovoltaic system is greater than the system output power threshold, the system control unit performs reasonable load distribution among the power supply units.
- the current power supply status parameters of each power supply unit include the current power supply power and current power supply capability of each power supply unit, and the system control unit is based on the current power supply power and current power supply of each power supply unit.
- the current power supply power of each power supply unit is adjusted to prevent one power supply unit or some of the power supply units in the at least two power supply units from working in a limit working state.
- the system control unit can adjust the current power supply of each power supply unit according to the current actual power supply capability of each power supply unit connected in parallel with the DC bus, so as to ensure the balance of power supply among the power supply units, thereby avoiding One power supply unit or part of the power supply units in the power supply unit supplies power with a power supply power that exceeds its current maximum power supply power, which has strong applicability.
- the current power supply state parameters of each power supply unit include the current maximum power supply power of each power supply unit, and the system control unit determines each power supply unit based on the current maximum power supply power of each power supply unit.
- the current maximum power supply ratio of the current maximum power supply power of at least two power supply units in the sum of the current maximum power supply power of at least two power supply units, and the reference power supply current value of each power supply unit is determined based on the current maximum power supply power ratio.
- the reference power supply current value of each power supply unit may be determined according to the current maximum power supply power of each power supply unit.
- the current power supply state parameters of each power supply unit further include the current equipment operating condition parameters of each power supply unit
- the system control unit is based on the current equipment operating condition parameters of each power supply unit and the current Maximum power supply power, determine the current corrected power supply power of each power supply unit, and determine the current correction of the current corrected power supply power of each power supply unit in the sum of the current corrected power supply power of at least two power supply units based on the current corrected power supply power of each power supply unit
- the power supply ratio is determined, and the current corrected power supply power ratio is determined as the current maximum power supply power ratio.
- the system control unit may determine the reference power supply current value of each power supply unit according to the current maximum power supply power of each power supply unit and the current equipment operating condition parameters.
- the system control unit acquires the respective power attenuation coefficients corresponding to the current equipment operating condition parameters of each power supply unit, and determines each power attenuation coefficient based on the current maximum power supply power and the power attenuation coefficient of each power supply unit.
- the current corrected supply power of the supply unit is
- the power attenuation coefficient can be used to reduce the maximum power supply power of a power supply unit with excessive device temperature, excessive device current stress, or excessive device voltage stress, thereby prolonging the service life of each power supply unit.
- the current device operating condition parameter includes at least one of the current device temperature, the current device current stress, or the current device voltage stress.
- the current power supply state parameters of each power supply unit further include the current power supply current of each power supply unit, and the system control unit is based on the current maximum power supply power ratio and at least two power supply units. The sum of the current power supply currents determines the reference power supply current value of each power supply unit.
- the current power supply state parameter of each power supply unit includes the current power supply current of each power supply unit
- the current maximum power supply ratio of each power supply unit and the sum of the current power supply currents of all power supply units can be calculated
- the product of is determined as the reference power supply current value of each power supply unit, so as to realize reasonable distribution of the power supply current value of each power supply unit based on the current actual power supply capability of each power supply unit.
- the system control unit sends a power supply correction instruction to each power supply unit, so that each power supply unit corrects the reference power supply current value of each power supply unit carried in the power supply power correction instruction,
- the current power supply power of each power supply unit is adjusted to be the reference power supply power of each power supply unit, wherein the reference power supply power of each power supply unit is determined by the reference power supply current value of each power supply unit.
- the system control unit determines the control correction amount of each power supply unit according to the reference power supply current value of each power supply unit and the current power supply state parameter, and sends the power supply correction to each power supply unit. instruction, so that each power supply unit adjusts the current power supply power of each power supply unit to the reference power supply power of each power supply unit according to the control correction amount of each power supply unit carried in the power supply power correction instruction, wherein the reference power supply power of each power supply unit is determined by The reference power supply current value of each power supply unit is determined.
- the system control unit after calculating and obtaining the control correction amount of each power supply unit, the system control unit sends a power supply power correction instruction including the control correction amount of the power supply unit to each power supply unit, and each power supply unit calculates according to the respective control correction amount Obtaining the respective target bus parameter voltages, and adjusting the power supply current value between each and the DC bus according to the respective target bus parameter voltages, can reduce the calculation amount of the system control unit and improve the processing efficiency of the system control unit.
- the system control unit determines the control correction amount of each power supply unit according to the reference power supply current value of each power supply unit and the current power supply state parameter, and determines the control correction amount of each power supply unit according to the initial bus reference voltage and each power supply unit.
- the control correction amount determines the target bus reference voltage of each power supply unit, and sends a power supply correction instruction to each power supply unit, so that each power supply unit adjusts each power supply according to the target bus reference voltage of each power supply unit carried in the power supply correction instruction.
- the current power supply power of the unit is the reference power supply power of each power supply unit, wherein the reference power supply power of each power supply unit is determined by the reference power supply current value of each power supply unit.
- each power supply unit does not need to calculate its own target bus reference voltage, and can directly adjust the power supply current value between each of the power supply units and the DC bus according to the respective target bus reference voltage included in the power supply correction instruction, reducing each The calculation amount of the power supply unit improves the processing efficiency of each power supply unit.
- the system control unit determines the target bus reference voltage of each power supply unit based on the initial bus reference voltage, the control correction amount of each power supply unit, and the voltage correction amount of each power supply unit, The voltage correction amount of each power supply unit is determined based on the current power supply state parameter of each power supply unit and the virtual impedance of each power supply unit.
- the initial bus reference voltage of each power supply unit can be corrected through the control correction amount of each power supply unit, so as to realize reasonable load distribution among the power supply units.
- the initial bus reference voltage of each power supply unit is corrected, thereby ensuring that each power supply unit is in a stable power supply state.
- the virtual impedance is determined based on a current power supply state parameter of the power supply unit.
- the first power supply unit of the at least two power supply units includes a system control unit.
- the power supply unit includes a DC/DC converter or a DC/AC converter, wherein the DC/DC converter is used to adjust the current power supply of the DC/DC converter,
- the DC/AC converter is used to adjust the current supply power of the DC/AC converter.
- the power supply unit may include a DC/DC converter connected in parallel with the DC bus or a DC/AC converter connected in parallel with the DC bus, which can improve the applicability of the photovoltaic system.
- the present application provides a power supply current control method for a photovoltaic system.
- the photovoltaic system includes a DC bus, at least two power supply units connected in parallel with the DC bus, and a DC/AC connected to the at least two power supply units through the DC bus.
- a converter wherein each of the at least two power supply units includes a DC/DC converter, and an input end of the DC/DC converter is connected to a DC power supply.
- the DC/AC converter obtains the current output state parameters of the DC/DC converters in each power supply unit, and determines the current output state parameters of the DC/DC converters in each power supply unit.
- the reference output current value of the DC/DC converter in each power supply unit, and the current output power of the DC/DC converter in each power supply unit is adjusted according to the reference output current value of the DC/DC converter in each power supply unit.
- the current output state parameters of the DC/DC converters in each power supply unit include the current output power and current output capability of the DC/DC converters in each power supply unit.
- the DC/AC converter adjusts the current output power of the DC/DC converter in each power supply unit according to the current output power and current output capability of the DC/DC converter in each power supply unit to avoid a DC/DC conversion in the photovoltaic system
- the converter or part of the DC/DC converter works in the extreme working state.
- the current output state parameter of the DC/DC converter in each power supply unit includes the current maximum output power of the DC/DC converter in each power supply unit.
- the DC/AC converter determines, based on the current maximum output power of the DC/DC converter in each power supply unit, the current maximum output power of the DC/DC converter in each power supply unit and the current maximum output power of the DC/DC converter in at least two power supply units
- the current maximum output power ratio in the sum of the maximum output powers, and the reference output current value of the DC/DC converter in each power supply unit is determined based on the current maximum output power ratio.
- the current output state parameters of the DC/DC converters in each power supply unit further include current equipment operating condition parameters of the DC/DC converters in each power supply unit.
- the DC/AC converter determines the current corrected output power of the DC/DC converter in each power supply unit based on the current equipment operating parameters and the current maximum output power of the DC/DC converter in each power supply unit, based on the DC/DC converter in each power supply unit
- the current corrected output power of the DC converter is determined, and the current corrected output power of the current corrected output power of the DC/DC converter in each power supply unit is determined in the sum of the current corrected output power of the DC/DC converter in at least two power supply units. ratio, and the current corrected output power ratio is determined as the current maximum output power ratio.
- the present application provides a power supply current control method for a photovoltaic system, wherein the photovoltaic system includes a DC bus and at least two power supply units connected in parallel to the DC bus. Obtain the current power supply state parameters of each power supply unit in the at least two power supply units, determine the reference power supply current value of each power supply unit according to the current power supply state parameter of each power supply unit, and determine the reference power supply current value of each power supply unit according to the reference power supply current value of each power supply unit. The current power supply is adjusted.
- the current power supply state parameters of each of the at least two power supply units are acquired.
- the current power supply state parameters of each power supply unit include the current power supply power and current power supply capability of each power supply unit.
- the current power supply of each power supply unit is adjusted according to the current power supply power and current power supply capability of each power supply unit, so as to prevent one or some of the power supply units in the at least two power supply units from working in a limit working state.
- the current power supply state parameters of each power supply unit include the current maximum power supply power of each power supply unit, and the current power supply unit of each power supply unit may be determined based on the current maximum power supply power of each power supply unit.
- the current maximum power supply power ratio of the maximum power supply power in the sum of the current maximum power supply powers of the at least two power supply units, and then the reference power supply current value of each power supply unit is determined based on the current maximum power supply power ratio.
- the current power supply state parameters of each power supply unit also include the current equipment operating condition parameters of each power supply unit, which may be based on the current equipment operating condition parameters and the current maximum power supply of each power supply unit. power, to determine the current corrected power supply power of each power supply unit; based on the current corrected power supply power of each power supply unit, determine the current corrected power supply power of each power supply unit in the sum of the current corrected power supply power of at least two power supply units ratio; and determine the current corrected power supply power ratio as the current maximum power supply power ratio.
- the respective power attenuation coefficients corresponding to the current equipment operating condition parameters of each power supply unit are obtained, and the power attenuation coefficient of each power supply unit is determined based on the current maximum power supply power and the power attenuation coefficient of each power supply unit.
- the current correction power supply is obtained.
- the current device operating condition parameter includes at least one of the current device temperature, the current device current stress, or the current device voltage stress.
- the current power supply state parameters of each power supply unit further include the current power supply current of each power supply unit, which may be based on the current maximum power supply power ratio and the current power supply of at least two power supply units. The sum of the currents determines the reference power supply current value of each power supply unit.
- a power supply correction instruction is sent to each power supply unit, so that each power supply unit adjusts each power supply according to the reference power supply current value of each power supply unit carried in the power supply correction instruction.
- the current power supply power of the unit is the reference power supply power of each power supply unit, wherein the reference power supply power of each power supply unit is determined by the reference power supply current value of each power supply unit.
- the control correction amount of each power supply unit is determined according to the reference power supply current value of each power supply unit and the current power supply state parameter, and a power supply power correction instruction is sent to each power supply unit to Make each power supply unit adjust the current power supply power of each power supply unit to be the reference power supply power of each power supply unit according to the control correction amount of each power supply unit carried in the power supply power correction instruction, wherein the reference power supply power of each power supply unit is determined by each power supply unit.
- the reference supply current value is determined.
- the control correction amount of each power supply unit is determined according to the reference power supply current value of each power supply unit and the current power supply state parameter, and the control correction amount of each power supply unit is determined according to the initial bus reference voltage and the control correction of each power supply unit.
- Determine the target bus reference voltage of each power supply unit and send a power supply correction instruction to each power supply unit, so that each power supply unit adjusts the current power supply unit according to the target bus reference voltage of each power supply unit carried in the power supply correction instruction
- the power supply is the reference power supply power of each power supply unit, wherein the reference power supply power of each power supply unit is determined by the reference power supply current value of each power supply unit.
- the target bus reference voltage of each power supply unit is determined based on the initial bus reference voltage, the control correction amount of each power supply unit, and the voltage correction amount of each power supply unit, wherein each The voltage correction amount of the power supply unit is determined based on the current power supply state parameter of each power supply unit and the virtual impedance of each power supply unit.
- the virtual impedance is determined based on a current power supply state parameter of the power supply unit.
- the power supply unit includes a DC/DC converter or a DC/AC converter, wherein the DC/DC converter is used to adjust the current power supply of the DC/DC converter, the DC The /AC converter is used to adjust the current supply power of the DC/AC converter.
- the present application provides a DC/AC converter for a photovoltaic system, wherein the photovoltaic system includes a DC bus, at least two power supply units connected in parallel to the DC bus, and a DC bus connected to the at least two power supply units.
- DC/AC converter wherein each of the at least two power supply units includes a DC/DC converter, and the input end of the DC/DC converter is connected to the DC power supply.
- the DC/AC converter includes:
- the acquisition and determination module is used to acquire the current output state parameters of the DC/DC converters in each power supply unit when the DC/AC converter is in the power-limited working mode, and according to the current output state parameters of the DC/DC converters in each power supply unit Determine the reference output current value of the DC/DC converter in each power supply unit;
- the power adjustment module is configured to adjust the current output power of the DC/DC converter in each power supply unit according to the reference output current value of the DC/DC converter in each power supply unit.
- the present application provides a power supply current control device for a photovoltaic system, wherein the photovoltaic system includes a DC bus and at least two power supply units connected in parallel to the DC bus.
- the supply current control device includes:
- an acquisition and determination module configured to acquire the current power supply state parameters of each of the at least two power supply units, and determine the reference power supply current value of each power supply unit according to the current power supply state parameters of each power supply unit;
- the power adjustment module is used for adjusting the current power supply of each power supply unit according to the reference supply current value of each power supply unit.
- FIG. 1 is a schematic structural diagram of a photovoltaic system provided by the present application.
- FIG. 3 is a schematic structural diagram of a pure storage system provided by the application.
- FIG. 4 is a schematic structural diagram of an optical storage system provided by the present application.
- FIG. 5 is a schematic diagram of a curve of the droop characteristic of the virtual impedance provided by the present application to the initial bus reference voltage
- FIG. 6 is a schematic flowchart of a method for controlling power supply current of a photovoltaic system provided by the present application
- FIG. 7 is another schematic flowchart of the power supply current control method of the photovoltaic system provided by the present application.
- FIG. 8 is a schematic structural diagram of a power supply current control device of a photovoltaic system provided by the present application.
- FIG. 9 is a schematic structural diagram of a DC/AC converter of a photovoltaic system provided by the present application.
- the photovoltaic system and its power supply current control method, device, and power supply unit provided by the present application can determine the reference power supply current value of each power supply unit according to the power supply state parameters of each parallel power supply unit, so as to realize load control according to the actual power supply capacity of each power supply unit.
- Reasonable distribution thereby extending the service life of each power supply unit, thereby reducing the operation and maintenance cost of the photovoltaic system.
- the photovoltaic system 100 includes a DC bus BUS (corresponding to the positive DC bus BUS+ and the negative DC bus BUS- in FIG. 1 ), and each power supply unit connected in parallel with the DC bus BUS.
- each power supply unit may include a power supply unit.
- Units 111,..., power supply unit 11n 1 or include power supply unit 121,..., power supply unit 12n 2 , n 1 is an integer greater than or equal to 2, and n 2 is an integer greater than or equal to 1.
- each power supply unit includes the power supply unit 111, . . .
- the power supply unit 11n 1 , the photovoltaic system 100 can realize the reasonable load distribution among the power supply units 111, . . . , the power supply unit 11n 1 ;
- the power supply units 111, . . . , and the power supply unit 11n1 all include a DC/DC converter, and the input end of the DC/DC converter is connected to the DC power supply for realizing the DC voltage conversion between the DC power supply and the DC bus.
- the DC power supply can be a photovoltaic string, at this time the DC/DC converter can convert the electric energy of the photovoltaic string to DC and supply it to the DC bus, so as to realize the power supply to the DC bus; the DC power supply can also be an energy storage battery string At this time, the DC/DC converter can convert the electric energy of the DC bus to DC and then supply it to the energy storage battery string, so as to realize the charging of the energy storage battery string.
- the photovoltaic string may include a plurality of photovoltaic modules connected in series and/or in parallel, and the photovoltaic modules are DC power sources formed by encapsulating solar cells in series and parallel, and are used to convert solar energy into electrical energy.
- the energy storage battery string may include a plurality of energy storage cells connected in series and/or in parallel.
- the power supply units 121, . . . , and the power supply units 12n 2 all include DC/AC converters, which can be used to convert the DC power on the DC bus into AC power that meets the power consumption requirements of the load, or to convert the DC power on the DC bus through the
- the inverter converts into alternating current that meets the requirements of the mains grid.
- the output ends of the power supply units 121, . . . , and the power supply unit 12n 2 can be connected to a step-up transformer (not shown in the figure) and then connected to the power grid 200, which can be determined according to the specific application environment, which is not described here. limited.
- the photovoltaic system 100 can output the inverted alternating current to the load or the grid 200 .
- the photovoltaic system 100 further includes a system control unit (not shown) for communicating with the power supply units 111, . . . , and the power supply units 11n 1 , or with the power supply units 121, . 2. Perform communication, and obtain the power supply state parameters of the power supply units 111 , .
- the system control unit may be an independent device, or may be integrated in other devices of the photovoltaic system 100, for example, integrated in any one of the power supply units 111, . . . , and the power supply units 11n 1 , or integrated in the power supply unit 121, . . , and any one of the power supply units 12n 2 .
- the system control unit communicates with the power supply unit through wireless communication (such as WiFi, Lora, Zig bee, etc.) or PLC communication.
- the system control unit (not shown in the figure) in the photovoltaic system 100 determines the reference power supply current values of the power supply units 111, .
- the bus power supply current value between the two is the respective reference power supply current value.
- n 2 is an integer greater than or equal to 2
- the above-mentioned power supply current control method of the photovoltaic system can distribute the power supply current value of each power supply unit according to the current actual power supply capacity of each power supply unit connected in parallel with the DC bus when the output power of the photovoltaic system is greater than the system output power threshold, so that Realize the reasonable distribution of loads among each power supply unit, thereby prolonging the service life of each power supply unit and reducing the operation and maintenance cost of the photovoltaic system.
- the technical solution provided in this application can be applied to a pure light photovoltaic scene, and the photovoltaic system provided in this application is a pure light system.
- FIG. 2 it is a schematic structural diagram of the pure optical system provided by the present application.
- the power supply units 111, . . . , the power supply unit 11n 1 may all be composed of a DC/DC converter and a photovoltaic string connected to the input end of the DC/DC converter, and the power supply units 121, . . .
- the units 12n 2 may all be DC/AC converters whose input terminals are connected to the DC bus BUS.
- the pure optical system 100 can also be applied to an uninterruptible power supply scenario, that is, an energy storage battery, such as a nickel-cadmium battery or a nickel-hydrogen battery, can be provided between the DC/AC converter and the power grid 200 .
- an energy storage battery such as a nickel-cadmium battery or a nickel-hydrogen battery
- lithium ion batteries lithium polymer batteries, etc.
- the technical solution provided by this application can be applied to a photovoltaic scenario of pure storage, and the photovoltaic system provided by this application is a pure storage system.
- FIG. 3 it is a schematic structural diagram of the pure storage system provided by the present application.
- the power supply units 111, . . . , and the power supply unit 11n 1 may all be composed of a DC/DC converter and an energy storage battery string connected to the input end of the DC/DC converter.
- the power supply units 121, . . . , And the power supply units 12n 2 can be both DC/AC converters whose input ends are connected to the DC bus BUS.
- the pure storage system 100 can also be applied to an uninterruptible power supply scenario, that is, an energy storage battery, such as a nickel-cadmium battery or a nickel-hydrogen battery, can be provided between the DC/AC converter and the power grid 200 .
- an energy storage battery such as a nickel-cadmium battery or a nickel-hydrogen battery
- lithium ion batteries lithium polymer batteries, etc.
- the technical solution provided in this application can be applied to a photovoltaic scenario of optical storage, and the photovoltaic system provided in this application is an optical storage system.
- FIG. 4 it is a schematic structural diagram of the optical storage system provided by the present application.
- the power supply units 111, . . . , and the power supply unit 11n1 include both a power supply unit composed of a DC/DC converter and a photovoltaic string connected to the input end of the DC/DC converter, and a power supply unit composed of a DC/DC converter.
- the optical storage system 100 may also be applied to an uninterruptible power supply scenario, that is, an energy storage battery, such as a nickel-cadmium battery or a nickel-hydrogen battery, may be provided between the DC/AC converter and the power grid 200 . , lithium ion batteries, lithium polymer batteries, etc.
- n 2 as an integer greater than or equal to 2 as an example, the specific implementation manner of controlling the power supply current of the photovoltaic system will be introduced.
- the system control unit when determining that the current output power of the photovoltaic system is greater than the system output power threshold, sends the power supply units (corresponding to the power supply units 111, . . . , .
- the power supply unit 11n 1 or the power supply unit 121 , . . . , the power supply unit 12n 2 in FIG. 1 ), sends a power supply parameter acquisition instruction.
- Each power supply unit sends its current power supply state parameter to the system control unit according to the power supply parameter acquisition instruction.
- the system output power threshold may be the output power threshold carried in the power limiting instruction sent by the user to the photovoltaic system, that is, the system output power threshold may be artificially defined.
- the system control unit determines the reference power supply current value of each power supply unit according to the received current power supply state parameters of each power supply unit.
- the current power supply state parameter of each power supply unit includes the current maximum power supply of each power supply unit.
- the current maximum power supply power of the power supply unit is the current maximum output power of the DC/DC converter in the power supply unit , that is, the maximum output power currently allowed by the DC/DC converter; when the power supply unit is any one of the power supply units 121, . . . , and the power supply units 12n 2 in FIG.
- the current maximum input power of the DC/AC converter in the power supply unit that is, the current maximum input power allowed by the DC/AC converter.
- the system control unit can obtain the system output power threshold and the DC bus voltage, and determine the quotient between the system output power threshold and the DC bus voltage as the total current of the photovoltaic system after power limitation.
- the system control unit can determine the current maximum power supply ratio of the i-th power supply unit according to the current maximum power supply power of each power supply unit as P Mi /(P M1 +...+P Mi +...+P Mn ), where P M1 , ..., P Mi , ..., P Mn are respectively the current maximum power supply power of the first power supply unit, ..., the current maximum power supply power of the ith power supply unit, ..., the current maximum power supply power of the nth power supply unit, i is an integer greater than or equal to 1 and less than or equal to n.
- each power supply unit is the power supply unit 111, . . . , the power supply unit 11n 1 in FIG . in, are respectively the current maximum output power of the DC/DC converter in the power supply unit 111, . . . , the current maximum output power of the DC/DC converter in the power supply unit 11n1 .
- each power supply unit is the power supply unit 121, . . . , the power supply unit 12n 2 in FIG . in, are the current maximum input power of the DC/AC converter in the power supply unit 121, . . . , the current maximum input power of the DC/AC converter in the power supply unit 12n 2 , respectively.
- the current power supply state parameters of each power supply unit also include current equipment operating condition parameters of each power supply unit.
- the system control unit may also determine the current corrected power supply power of each power supply unit based on the current equipment operating condition parameters and the current maximum power supply power of each power supply unit, and determine the current corrected power supply power of each power supply unit based on the current corrected power supply power of each power supply unit
- the current corrected power supply ratio in the sum of the current corrected power supply powers of the at least two power supply units, and the current corrected power supply power ratio of each power supply unit is determined as the current maximum power supply power ratio of each power supply unit.
- the current equipment operating condition parameter of the power supply unit may be the current equipment of the DC/DC converter in the power supply unit Working condition parameters; when the power supply unit is any one of the power supply units 121, . . . , and the power supply units 12n 2 in FIG. Current equipment operating parameters.
- the current equipment operating condition parameters include at least one of the current equipment temperature, the current equipment current stress or the current equipment voltage stress, wherein the current equipment current stress is the ratio of the current working voltage of the equipment to the rated voltage, and the current equipment current stress is the current equipment working voltage. The ratio of current to rated current.
- the current device voltage stress of the power supply unit 111 is the ratio of the current output voltage of the DC/DC converter in the power supply unit 111 to the rated voltage
- the current device current stress of the power supply unit 111 is the DC/DC converter in the power supply unit 111.
- the ratio of the current output current to the rated current is the ratio of the current output current to the rated current.
- the system control unit can obtain the power attenuation coefficient corresponding to the current equipment temperature of each power supply unit by looking up a table, and calculate the difference between the current maximum power supply power of each power supply unit and the power attenuation coefficient corresponding to the current equipment temperature of each power supply unit.
- the product of each power supply unit is determined as the current corrected power supply power of each power supply unit, and then the current corrected power supply power ratio of each power supply unit is calculated according to the current corrected power supply power of each power supply unit, and the current corrected power supply power ratio of each power supply unit is determined. It is the current maximum power supply ratio of each power supply unit.
- the relationship between the power attenuation coefficient of the power supply unit and the device temperature may be that the power attenuation coefficient of the power supply unit decreases as the device temperature of the power supply unit increases, or it may be the power attenuation of different values corresponding to different device temperature ranges coefficient, which is not specifically limited here. Except that the current equipment operating condition parameter is the current equipment temperature, other conditions can be obtained in the same way according to the current equipment operating condition parameter being the current equipment temperature, which will not be repeated here.
- the current maximum power supply power of the power supply units with excessive device temperature, excessive device current stress or excessive device voltage stress can be reduced by the power attenuation coefficient, thereby prolonging the service life of each power supply unit.
- the system control unit determines the product of the total current after the power limitation of the photovoltaic system and the maximum power supply ratio of each power supply unit as the reference power supply current value of each power supply unit.
- the reference power supply current value of each power supply unit is calculated and obtained according to the current maximum power supply power ratio of each power supply unit and the total current after the power limitation of the photovoltaic system, not only according to the current actual power supply capacity of each power supply unit. Realize the reasonable distribution of the load, that is, realize the balanced distribution of the power supply of each power supply unit, prolong the service life of each power supply unit, and reduce the operation and maintenance cost of the photovoltaic system. It can also be ensured that the output power of the photovoltaic system is less than the system output power threshold after each power supply unit performs feedback adjustment on the respective power supply current values according to the respective reference power supply current values.
- the current power supply state parameters of each power supply unit include the current maximum power supply power and the current power supply current of each power supply unit.
- the current maximum power supply power and current power supply current of the power supply unit are respectively the DC/DC converter in the power supply unit.
- the current maximum power supply power and the current power supply current of the power supply unit are the current maximum input power of the DC/AC converter and the current input current of the DC/AC converter in the power supply unit, respectively, and can be passed through the DC/AC
- the system control unit can calculate the current maximum power supply ratio of the current maximum power supply power of each power supply unit to the sum of the current maximum power supply power of at least two power supply units according to the current maximum power supply power of each power supply unit connected in parallel to the DC bus.
- the current power supply state parameters of each power supply unit also include current equipment operating condition parameters of each power supply unit.
- the system control unit may also determine the current corrected power supply power of each power supply unit based on the current equipment operating condition parameters and the current maximum power supply power of each power supply unit, and determine the current corrected power supply power of each power supply unit based on the current corrected power supply power of each power supply unit
- the current corrected power supply ratio in the sum of the current corrected power supply powers of the at least two power supply units, and the current corrected power supply power ratio of each power supply unit is determined as the current maximum power supply power ratio of each power supply unit.
- the system control unit determines the product of the sum of the current power supply currents of each power supply unit and the current maximum power supply ratio of each power supply unit as the reference power supply current value of each power supply unit.
- each power supply unit is the power supply unit 111, . . . , the power supply unit 11n 1 in FIG . in, is the current maximum power supply ratio of the power supply unit 11n 1 , are respectively the current output current of the DC/DC converter in the power supply unit 111 , . . . , the current output current of the DC/DC converter in the power supply unit 11n 1 .
- each power supply unit is the power supply unit 121, . . . , the power supply unit 12n 2 in FIG. 1
- the reference power supply current value of the power supply unit 12n 2 is in is the current maximum power supply ratio of the power supply unit 12n 2
- the current power supply state parameters of each power supply unit include current power supply power and current power supply capability of each power supply unit.
- the current power supply capability of the power supply unit includes the current maximum power supply power allowed by the power supply unit, that is, the current maximum power supply power.
- the current maximum power supply power of the power supply unit is the current maximum output power of the DC/DC converter in the power supply unit;
- the current maximum power supply power of the power supply unit is the current maximum input power of the DC/AC converter in the power supply unit.
- the system control unit may calculate the current maximum power supply ratio of the current maximum power supply power of each power supply unit to the sum of the current maximum power supply power of at least two power supply units according to the current maximum power supply power of each power supply unit.
- the current power supply capability of each power supply unit further includes current equipment operating condition parameters of each power supply unit.
- the system control unit may also determine the current corrected power supply power of each power supply unit based on the current equipment operating condition parameters and the current maximum power supply power of each power supply unit, and determine the current corrected power supply power of each power supply unit based on the current corrected power supply power of each power supply unit
- the current corrected power supply ratio in the sum of the current corrected power supply powers of the at least two power supply units, and the current corrected power supply power ratio of each power supply unit is determined as the current maximum power supply power ratio of each power supply unit.
- the system control unit determines the product of the sum of the current power supply currents of each power supply unit and the current maximum power supply ratio of each power supply unit as the reference power supply current value of each power supply unit.
- the current power supply of each power supply unit can be reasonably allocated according to the current actual power supply capability of each power supply unit, so as to realize the balance of power supply among the power supply units, and avoid one or part of the power supply units in each power supply unit.
- Work in the limit power supply state that is, the power supply unit supplies power with a power supply power that exceeds the current maximum power supply power that the power supply unit can withstand), thereby extending the service life of each power supply unit and reducing the operation and maintenance cost of the photovoltaic system.
- the system control unit adjusts the current power supply of each power supply unit according to the reference power supply current value of each power supply unit, so that the current power supply of each power supply unit is the reference power supply of each power supply unit, wherein the reference power supply of the power supply unit Power is the product of the supply unit's reference supply current and the DC bus voltage. Since the power supply voltages (that is, the DC bus voltage) between each power supply unit connected in parallel with the DC bus are equal, when adjusting the current power supply of each power supply unit to the reference power supply of each power supply unit, only The power supply current value between each power supply unit and the DC bus can be adjusted to the reference power supply current value of each power supply unit.
- the system control unit sends a power supply correction instruction to each power supply unit, and the power supply unit adjusts the power supply current value between the power supply unit and the DC bus to the reference power supply current value of the power supply unit according to the received power supply power correction instruction , so that the current power supply of the power supply unit is the reference power supply of the power supply unit.
- the supply power correction instruction includes a reference supply current value of the power supply unit.
- the power supply unit may use the difference between the reference power supply current value of the power supply unit and the current power supply current value as a proportional-integral (Proportion Integration, PI) control algorithm
- PI proportional-integral
- the power supply unit may also determine the virtual impedance value corresponding to the current power supply current of the power supply unit as the virtual impedance value of the power supply unit, and determine the product between the current power supply current of the power supply unit and the virtual impedance value as the voltage correction of the power supply unit. and determine the sum of the voltage correction amount of the power supply unit, the control correction amount and the initial busbar reference voltage as the target busbar reference voltage of the power supply unit.
- the current power supply current of the power supply unit is the current input current of the DC/AC converter in the power supply unit.
- the virtual impedance value may be a fixed value, or may be a non-positive number that increases as the power supply current or power supply of the power supply unit increases.
- FIG. 5 is a schematic diagram of a curve of the droop characteristic of the virtual impedance provided by the present application to the initial bus reference voltage.
- the virtual impedance value corresponding to the left part of Figure 5 is a fixed value, that is, the slope of the straight line -R.
- the straight line indicates that as the power supply current I of the power supply unit increases, the bus reference voltage U ref of the power supply unit continues to decrease. small, of which, is the initial bus reference voltage of the power supply unit.
- the curve 5 corresponds to the virtual impedance value that is a non-positive number that increases with the increase of the power supply current or power supply of the power supply unit, that is, the virtual impedance value corresponding to the power supply current I is the tangent of the power supply current I at the curve.
- Slope R(I) the curve indicates that with the increase of the power supply current I of the power supply unit, the bus reference voltage U ref of the power supply unit decreases continuously, wherein,
- the power supply unit can determine its own control correction amount according to its own current power supply current value and the reference power supply current value of the power supply unit included in the power supply power correction instruction, and use its own control correction amount to determine its own control correction amount.
- the initial bus reference voltage of the power supply unit can be corrected according to its current actual power supply capability, and further, the power supply unit can further correct its own initial bus reference voltage through the droop characteristic of the virtual impedance, thereby ensuring that the power supply unit is in a stable state. power supply status.
- the target bus reference voltage of the power supply unit is calculated by the power supply unit according to the reference supply current value of the power supply unit sent by the system control unit, which can reduce the calculation amount of the system control unit and improve the processing efficiency of the system control unit.
- the supply power correction instruction includes a control correction amount of the power supply unit.
- the system control unit Before the system control unit sends the power supply correction instruction to each power supply unit, the system control unit can use the difference between the reference power supply current value of each power supply unit and the corresponding current power supply current value as the input parameter of the PI control algorithm, respectively, The control correction amount of each power supply unit is determined, and the power supply power correction instruction is sent to each power supply unit.
- Each power supply unit receives the power supply correction instruction, and determines the sum of the respective initial bus reference voltage and the control correction amount of the power supply unit included in the supply power correction instruction as the respective target bus reference voltage. Further, the power supply unit may also determine the virtual impedance value corresponding to the current power supply current of the power supply unit as the virtual impedance value of the power supply unit, and determine the product between the power supply current of the power supply unit and the virtual impedance value as the voltage correction amount of the power supply unit. , and the sum of the voltage correction amount of the power supply unit, the control correction amount and the initial busbar reference voltage is determined as the target busbar reference voltage of the power supply unit.
- the supply power correction instruction includes a target bus reference voltage of the power supply unit.
- the system control unit Before the system control unit sends the power supply correction instruction to each power supply unit, the system control unit can use the difference between the reference power supply current value of each power supply unit and the corresponding current power supply current value as the input parameter of the PI control algorithm, respectively, The control correction amount of each power supply unit is determined, and the sum of the control correction amount of each power supply unit and the initial bus reference voltage is determined as the target bus reference voltage of each power supply unit. Further, the system control unit may also determine the virtual impedance value corresponding to the current power supply current of each power supply unit as the virtual impedance value of each power supply unit, and determine the product between the power supply current of each power supply unit and the virtual impedance value as each power supply unit.
- the voltage correction amount of each power supply unit, and the sum between the voltage correction amount of each power supply unit, the control correction amount and the initial busbar reference voltage is determined as the target busbar reference voltage of each power supply unit, and the target busbar reference voltage is sent to each power supply unit. power supply correction command.
- the power supply correction instruction provided in the present application may include any one of the reference supply current value of the power supply unit, the control correction amount and the target bus reference voltage, which can improve the applicability of the photovoltaic system.
- the system control unit sends a power supply correction instruction to each power supply unit.
- Each power supply unit determines the respective initial busbar reference voltage as the respective target busbar reference voltage according to the power supply power correction instruction.
- each power supply unit can output the voltage difference between the target bus reference voltage and the DC bus voltage to the respective switching power supply control circuit (such as a pulse width modulation circuit), and the switching power supply control circuit is based on the input voltage difference.
- the PWM wave is output, and the PWM wave is output to the switch circuit of the power supply unit to control the turn-on frequency of the switch circuit, and then control the power supply current value between each power supply unit and the DC bus to the respective reference power supply current value.
- each power supply unit is a power supply unit 111, .
- each power supply unit is the power supply unit 121, . . . , power supply unit 12n 2 in FIG. 1
- the power supply current value between each power supply unit and the DC bus is the input current value of the DC/AC converter in each power supply unit.
- system control unit may be a device that is independent of each power supply unit in the photovoltaic system, or may be a DC/ DC converter or DC/AC converter.
- the system control unit can distribute the power supply current value of each power supply unit according to the current actual power supply capability of each power supply unit connected in parallel with the DC bus, so that Realize the reasonable distribution of the load among the power supply units (that is, realize the balance of power supply between the power supply units), avoid one or part of the power supply units in the power supply units from working in the limit power supply state, thereby prolonging the service life of each power supply unit, Reduce the operation and maintenance costs of photovoltaic systems.
- the system control unit no longer performs load balancing for each power supply unit, and each power supply unit determines the respective initial busbar reference voltage as the respective target busbar reference voltage , and adjust the power supply current value between each and the DC bus according to the respective target bus reference voltage, which can ensure that each power supply unit supplies power with the current maximum power supply, thereby increasing the power generation of the photovoltaic system.
- n 2 1 as an example, a specific implementation manner of controlling the power supply current of the photovoltaic system will be introduced.
- the DC/AC converter when it is determined that the current output power of the photovoltaic system is greater than the system output power threshold, sends the power supply units 111, . . . /DC converter, send the output parameter acquisition command.
- the power supply units 111 , . . . and the DC/DC converters in the power supply unit 11n 1 send respective current output state parameters to the DC/AC converters according to the output parameter acquisition instruction.
- the DC/AC converter determines the reference output current value of the DC/DC converter in each power supply unit according to the received power supply units 111, . . . , and the current output state parameters of the DC/DC converter in each power supply unit in the power supply unit 11n1 .
- the current output state parameter of the DC/DC converter in each power supply unit includes the current maximum output power of the DC/DC converter in each power supply unit.
- the DC/AC converter can obtain the system output power threshold and the DC bus voltage, and determine the quotient between the system output power threshold and the DC bus voltage as the total current of the photovoltaic system after power limitation.
- the DC/AC converter can calculate the current maximum output power of the DC/DC converter in each power supply according to the current maximum output power of the DC/DC converter in each power supply unit. The proportion of the sum is obtained to obtain the current maximum output power proportion of the DC/DC converter in each power supply unit.
- the current output state parameters of the DC/DC converters in each power supply unit also include current equipment operating condition parameters of the DC/DC converters in each power supply unit.
- the current equipment operating condition parameter includes at least one of the current equipment temperature, the current equipment current stress or the current equipment voltage stress.
- the DC/AC converter can also determine the current modified power supply of each DC/DC converter based on the current equipment operating parameters and the current maximum power supply of each DC/DC converter, and based on the current modified power supply of each DC/DC converter power, determining the proportion of the current corrected power supply power of each DC/DC converter in the sum of the current corrected power supply power of at least two DC/DC converters, and calculating the current corrected power supply of each DC/DC converter
- the power supply ratio is determined as the current maximum output power ratio of each DC/DC converter.
- the DC/AC converter can reduce the current maximum output power of the DC/DC converter with excessive equipment temperature, excessive equipment current stress or excessive equipment voltage stress through the power attenuation coefficient, thereby extending the power of each DC/DC converter. the life of the converter.
- the DC/AC converter determines the product of the total current of the photovoltaic system after power limitation and the ratio of the maximum output power of each DC/DC converter as the reference output current value of each DC/DC converter.
- the DC/AC converter in this embodiment calculates the reference output current value of each DC/DC converter according to the current maximum output power ratio of each DC/DC converter and the total current after the power limitation of the photovoltaic system, It can not only realize the reasonable distribution of the load according to the current actual output capacity of each DC/DC converter, that is, realize the balanced distribution of the output power of each DC/DC converter, prolong the service life of each DC/DC converter, and reduce the photovoltaic system. operation and maintenance costs. It can also be ensured that the output power of the photovoltaic system is less than the system output power threshold after each DC/DC converter performs feedback adjustment on the respective output current values according to the respective reference output current values.
- the current output state parameters of the DC/DC converters in each power supply unit include current maximum output power and current output current of the DC/DC converters of each power supply unit.
- the DC/AC converter can calculate the current maximum output power of each DC/DC converter in the current maximum output power of at least two DC/DC converters according to the current maximum output power of each DC/DC converter connected in parallel with the DC bus The current maximum output power ratio in the sum.
- the current output state parameters of the DC/DC converters in each power supply unit also include current equipment operating condition parameters of the DC/DC converters in each power supply unit.
- the DC/AC converter can also determine the current corrected output power of each DC/DC converter based on the current equipment operating parameters and the current maximum output power of each DC/DC converter, and based on the current corrected output of each DC/DC converter power, determining the current corrected output power ratio of the current corrected output power of each DC/DC converter in the sum of the current corrected output power of at least two DC/DC converters, and calculating the current corrected output power of each DC/DC converter
- the output power ratio is determined as the current maximum output power ratio of each DC/DC converter.
- the DC/AC converter determines the product of the sum of the current output currents of each DC/DC converter and the current maximum output power ratio of each DC/DC converter as a reference for each DC/DC converter output current value.
- the current output state parameters of the DC/DC converters in each power supply unit include current output power and current output capability of the DC/DC converters in each power supply unit.
- the current output capability of the DC/DC converter in the power supply unit includes the current maximum output power of the DC/DC converter in the power supply unit, that is, the current maximum output power of the DC/DC converter.
- the DC/AC converter may calculate the current maximum output power of each DC/DC converter in the sum of the current maximum output powers of at least two DC/DC converters according to the current maximum output power of each DC/DC converter Maximum output power ratio.
- the current output capability of the DC/DC converter in each power supply unit also includes current equipment operating condition parameters of the DC/DC converter in each power supply unit.
- the DC/AC converter can also determine the current corrected output power of each DC/DC converter based on the current equipment operating parameters and the current maximum output power of each DC/DC converter, and based on the current corrected output of each DC/DC converter power, determining the current corrected output power ratio of the current corrected output power of each DC/DC converter in the sum of the current corrected output power of at least two DC/DC converters, and calculating the current corrected output power of each DC/DC converter
- the output power ratio is determined as the current maximum output power ratio of each DC/DC converter.
- the DC/AC converter determines the product of the sum of the current output currents of each DC/DC converter and the current maximum output power ratio of each DC/DC converter as a reference for each DC/DC converter output current value.
- the DC/AC converter in this embodiment can reasonably distribute the current output power of each DC/DC converter according to the current actual output capability of each DC/DC converter, so as to realize the output power between each DC/DC converter. Power balance, to prevent one or part of the DC/DC converters from working in the limit power supply state (that is, the output power of the DC/DC converter exceeds the maximum output power that the DC/DC converter can currently bear) work), thereby extending the service life of each DC/DC converter and reducing the operation and maintenance cost of the photovoltaic system.
- the DC/AC converter adjusts the current output power of each DC/DC converter according to the reference output current value of each DC/DC converter, so that the current output power of each DC/DC converter is The reference output power of the converter, wherein the reference output power of the DC/DC converter is the product of the reference output current of the DC/DC converter and the DC bus voltage. Since the output voltages (that is, the DC bus voltage) between the DC/DC converters connected in parallel on the DC bus and the DC bus are all equal, when adjusting the current output power of each DC/DC converter, the When the reference output power of the converter is adjusted, it is only necessary to adjust the output current value between each DC/DC converter and the DC bus to the reference output current value of each DC/DC converter.
- n 2 is an integer greater than or equal to 2
- n 2 is an integer greater than or equal to 2
- the DC/AC converter can perform the operation of each DC/DC converter according to the current actual output capability of each DC/DC converter connected in parallel with the DC bus.
- the output current value of each DC/DC converter is distributed, so as to realize the reasonable distribution of the load among the various DC/DC converters (that is, to realize the output power balance between the various DC/DC converters), and avoid one or part of the various DC/DC converters.
- the DC/DC converter works in the limit power supply state, thereby prolonging the service life of each DC/DC converter and reducing the operation and maintenance cost of the photovoltaic system.
- the DC/AC converter no longer performs load balancing for each DC/DC converter, and each DC/DC converter uses the respective initial bus reference voltage It is determined as the respective target bus reference voltage, and the output current value between each and the DC bus is adjusted according to the respective target bus reference voltage, which can ensure that each DC/DC converter outputs at the current maximum output power, thereby improving the photovoltaic system. power generation.
- n 2 is an integer greater than or equal to 2.
- FIG. 6 it is a schematic flowchart of a method for controlling power supply current of a photovoltaic system provided by the present application.
- the power supply current control method of the photovoltaic system provided by the embodiment of the present application may include the steps:
- S101 Acquire current power supply state parameters of each of the at least two power supply units, and determine a reference power supply current value of each power supply unit according to the current power supply state parameters of each power supply unit.
- the power supply current control device when it is determined that the current output power of the photovoltaic system is greater than the system output power threshold, the power supply current control device sends the power supply unit (corresponding to the power supply unit 111 in FIG. 1 , . . . , the power supply unit 11n 1 , or corresponding to the power supply unit 121 in FIG. 1 , .
- Each power supply unit sends its current power supply state parameter to the power supply current control device according to the received power supply parameter acquisition instruction.
- the current power supply state parameter of each power supply unit includes the current maximum power supply of each power supply unit.
- the power supply current control device can obtain the system output power threshold and the DC bus voltage, and determine the quotient between the system output power threshold and the DC bus voltage as the total current of the photovoltaic system after power limitation.
- the product of the total current after the power limitation of the photovoltaic system and the current maximum power supply ratio of each power supply unit is determined as the reference power supply current value of each power supply unit.
- the current power supply state parameters of each power supply unit include the current maximum power supply power and the current power supply current of each power supply unit.
- the power supply current control device may determine the product of the sum of the current power supply currents of each power supply unit and the current maximum power supply ratio of each power supply unit as the reference power supply current value of each power supply unit.
- the current power supply state parameters of each power supply unit include current power supply power and current power supply capability of each power supply unit.
- the current power supply capability of the power supply unit includes the current maximum power supply power allowed by the power supply unit, that is, the current maximum power supply power.
- the power supply current control device may calculate the current maximum power supply ratio of the current maximum power supply power of each power supply unit to the sum of the current maximum power supply power of at least two power supply units according to the current maximum power supply power of each power supply unit.
- the current maximum power supply ratio of each power supply unit may be determined directly by the power supply current control device according to the current maximum power supply power of each power supply unit, or may be the current power supply state of each power supply unit
- the parameters also include the current equipment working condition parameters of each power supply unit or the current power supply capability of each power supply unit also includes the current equipment working condition parameters of each power supply unit.
- the current maximum power supply power of each power supply unit is corrected, and the current maximum power supply power ratio of each power supply unit is determined according to the current corrected power supply power ratio of each power supply unit.
- the current equipment operating condition parameter includes at least one of the current equipment temperature, the current equipment current stress or the current equipment voltage stress.
- S102 Adjust the current power supply of each power supply unit according to the reference power supply current value of each power supply unit.
- the power supply current control device sends a power supply correction instruction to each power supply unit, and the power supply unit adjusts the power supply current value between the power supply unit and the DC bus according to the received power supply power correction instruction to be the reference power supply current of the power supply unit value, so that the current power supply power of the power supply unit is the reference power supply power of the power supply unit.
- the supply power correction instruction includes a reference supply current value of the power supply unit.
- the supply power correction instruction includes a control correction amount of the power supply unit.
- the power supply current control device Before the power supply current control device sends the power supply correction instruction to each power supply unit, the power supply current control device can use the difference between the reference power supply current value of each power supply unit and the current power supply current value as the input parameter of the PI control algorithm, respectively, The control correction amount of each power supply unit is determined, and the power supply power correction instruction is sent to each power supply unit.
- the supply power correction instruction includes a target bus reference voltage of the power supply unit.
- the power supply current control device Before the power supply current control device sends the power supply correction instruction to each power supply unit, the power supply current control device can use the difference between the reference power supply current value of each power supply unit and the current power supply current value as the input parameter of the PI control algorithm, respectively, The control correction amount of each power supply unit is determined, and the sum of the control correction amount of each power supply unit and the initial bus reference voltage is determined as the target bus reference voltage of each power supply unit. Further, the power supply current control device can also determine the virtual impedance value corresponding to the current power supply current of each power supply unit as the virtual impedance value of each power supply unit, and determine the product between the power supply current of each power supply unit and the virtual impedance value as each power supply unit.
- the voltage correction amount of the power supply unit, and the sum between the voltage correction amount of each power supply unit, the control correction amount and the initial busbar reference voltage is determined as the target busbar reference voltage of each power supply unit, and the target busbar reference voltage is sent to each power supply unit. Voltage supply power correction command.
- the supply power correction instruction provided by the present application may include any one of the reference supply current value of the power supply unit, the control correction amount and the target bus reference voltage, which can improve the applicability of the supply current control method.
- the power supply current control device may be a device that is independent of each power supply unit in the photovoltaic system, or may be a DC power supply unit included in any power supply unit connected in parallel to each power supply unit of the DC bus. /DC converter or DC/AC converter.
- the power supply current control device when the output power of the photovoltaic system is greater than the system output power threshold, can perform the power supply current value of each power supply unit according to the current actual power supply capability of each power supply unit connected in parallel with the DC bus. Distribution (that is, to achieve the balance of power supply between each power supply unit), to prevent one or part of the power supply units from working in the limit power supply state, so as to realize the reasonable distribution of the load among the power supply units, thereby prolonging the power supply of each power supply unit. service life, reducing the operation and maintenance cost of the photovoltaic system.
- FIG. 7 it is another schematic flowchart of the power supply current control method of the photovoltaic system provided by the present application.
- the power supply current control method of the photovoltaic system provided by the embodiment of the present application may include the steps:
- the DC/AC converter when it is determined that the current output power of the photovoltaic system is greater than the system output power threshold, the DC/AC converter sends DC/AC power to the power supply units 111, .
- the DC converter sends an output parameter acquisition command.
- the power supply units 111 , . . . and the DC/DC converters in the power supply unit 11n 1 send respective current output state parameters to the DC/AC converters according to the received output parameter acquisition instruction.
- the current output state parameter of the DC/DC converter in each power supply unit includes the current maximum output power of the DC/DC converter in each power supply unit.
- the DC/AC converter can obtain the system output power threshold and the DC bus voltage, and determine the quotient between the system output power threshold and the DC bus voltage as the total current of the photovoltaic system after power limitation.
- the product of the total current after the power limitation of the photovoltaic system and the current maximum output power ratio of each DC/DC converter is determined as the reference output current value of each DC/DC converter.
- the current output state parameters of the DC/DC converters in each power supply unit include current maximum output power and current output current of the DC/DC converters of each power supply unit.
- the DC/AC converter can determine the product of the sum of the current output currents of each DC/DC converter and the current maximum output power ratio of each DC/DC converter as the reference output of each DC/DC converter current value.
- the current output state parameters of the DC/DC converters in each power supply unit include current output power and current output capability of the DC/DC converters in each power supply unit.
- the current output capability of the DC/DC converter in the power supply unit includes the current maximum output power of the DC/DC converter in the power supply unit, that is, the current maximum output power of the DC/DC converter.
- the DC/AC converter may calculate the current maximum output power of each DC/DC converter in the sum of the current maximum output powers of at least two DC/DC converters according to the current maximum output power of each DC/DC converter Maximum output power ratio.
- the current maximum output power ratio of each DC/DC converter may be directly determined by the DC/AC converter according to the current maximum output power of each DC/DC converter, or it may be
- the current output state parameters of each DC/DC converter also include the current equipment operating condition parameters of each DC/DC converter or the current output capability of each DC/DC converter also includes the current equipment operating condition parameters of each DC/DC converter
- the DC/AC converter corrects the current maximum output power of each DC/DC converter according to the current equipment operating parameters of each DC/DC converter, and corrects the current maximum output power of each DC/DC converter according to the current corrected output power of each DC/DC converter.
- the ratio determines the current maximum output power ratio of each DC/DC converter.
- the current equipment operating condition parameter includes at least one of the current equipment temperature, the current equipment current stress or the current equipment voltage stress.
- S202 Adjust the current output power of the DC/DC converter in each power supply unit according to the reference output current value of the DC/DC converter in each power supply unit.
- the DC/AC converter sends an output power correction command to each DC/DC converter, and the DC/DC converter adjusts the output current value with the DC bus according to the received output power correction command is the reference output current value of the DC/DC converter, so that the current output power of the DC/DC converter is the reference output power of the DC/DC converter.
- the output power correction command includes a reference output current value of the DC/DC converter.
- the output power correction instruction includes a control correction amount of the DC/DC converter.
- the DC/AC converter may calculate the difference between the reference output current value and the current output current value of each DC/DC converter, respectively As the input parameter of the PI control algorithm, the control correction amount of each DC/DC converter is decided, and the output power correction command is sent to each DC/DC converter.
- the output power correction command includes a target bus reference voltage of the DC/DC converter.
- the DC/AC converter may calculate the difference between the reference output current value and the current output current value of each DC/DC converter, respectively As the input parameter of the PI control algorithm, the control correction amount of each DC/DC converter is determined, and the sum of the control correction amount of each DC/DC converter and the initial bus reference voltage is determined as the target of each DC/DC converter Bus reference voltage. Further, the DC/AC converter can also determine the virtual impedance value corresponding to the current output current of each DC/DC converter as the virtual impedance value of each DC/DC converter, and the current output current of each DC/DC converter can be determined as the virtual impedance value of each DC/DC converter.
- the virtual impedance value is determined as the voltage correction amount of each DC/DC converter, and the sum between the voltage correction amount of each DC/DC converter, the control correction amount and the initial bus reference voltage is determined as each DC/DC converter / the target bus reference voltage of the DC converter, and send an output power correction command including the target bus reference voltage to each DC/DC converter.
- the output power correction instruction provided in this application can include any one of the reference supply current value of the DC/DC converter, the control correction amount and the target bus reference voltage, which can improve the applicability of the supply current control method.
- the DC/AC converter when the output power of the photovoltaic system is greater than the system output power threshold, the DC/AC converter can perform a calculation on each DC/DC converter according to the current actual output capability of each DC/DC converter connected in parallel with the DC bus.
- the output current value of the converter is distributed (that is, the output power balance between each DC/DC converter is realized), so as to avoid one or some DC/DC converters in each DC/DC converter from working in the limit power supply state, so as to realize
- the load distribution among the various DC/DC converters is reasonable, thereby extending the service life of each DC/DC converter and reducing the operation and maintenance cost of the photovoltaic system.
- n 2 is an integer greater than or equal to 2.
- the power supply current control device 8 may include: an acquisition and determination module 81 and a power adjustment module 82 .
- the obtaining and determining module 81 is configured to obtain the current power supply state parameters of each of the above-mentioned at least two power supply units, and determine the reference power supply current value of each of the above-mentioned power supply units according to the current power supply state parameters of each of the above-mentioned power supply units;
- the power adjustment module 82 is configured to adjust the current power supply of each power supply unit according to the reference power supply current value of each power supply unit.
- the above-mentioned power supply current control device further includes:
- the system power determination module 83 is configured to determine that the current output power of the photovoltaic system is greater than the system output power threshold.
- the current power supply state parameters of each power supply unit include the current power supply power and current power supply capability of the above-mentioned respective power supply units;
- the above-mentioned power supply current control device further includes:
- the current power supply adjustment module 84 is configured to adjust the current power supply of each power supply unit according to the current power supply power and current power supply capability of each power supply unit, so as to avoid one power supply unit or part of the power supply unit in the at least two power supply units. Work in extreme working conditions.
- the current power supply state parameters of each of the above-mentioned power supply units include the current maximum power supply power of each of the above-mentioned power supply units
- the above acquisition and determination module 81 includes:
- the power ratio determination unit 811 is configured to determine, based on the current maximum power supply power of each power supply unit, the current maximum power supply power of the current maximum power supply power of each power supply unit in the sum of the current maximum power supply power of the at least two power supply units. proportion;
- the reference current determining unit 812 is configured to determine the reference power supply current value of each power supply unit based on the above-mentioned maximum power supply ratio.
- the current power supply state parameters of the above-mentioned respective power supply units further include the current equipment operating condition parameters of the above-mentioned respective power supply units;
- the above-mentioned power ratio determination unit 811 is configured to determine the current modified power supply power of each of the above-mentioned power supply units based on the current equipment operating condition parameters and the current maximum power supply power of each of the above-mentioned power supply units;
- the above-mentioned current corrected power supply power ratio is determined as the above-mentioned current maximum power supply power ratio.
- the above-mentioned power ratio determination unit 811 is configured to obtain the respective power attenuation coefficients corresponding to the current equipment operating condition parameters of the above-mentioned power supply units, based on the current maximum power supply power and the power attenuation coefficients of the above-mentioned respective power supply units Determine the current corrected power supply power of each of the above-mentioned power supply units.
- the above-mentioned current equipment operating condition parameter includes at least one of current equipment temperature, current equipment current stress or current equipment voltage stress.
- the current power supply state parameter of each of the above-mentioned power supply units further includes the current power supply current of each of the above-mentioned power supply units
- the reference current determining unit 812 is configured to determine the reference power supply current value of each power supply unit based on the current maximum power supply power ratio and the sum of the current power supply currents of the at least two power supply units.
- the power adjustment module 82 is configured to send a power supply correction instruction to each of the power supply units, so that each power supply unit adjusts the power supply according to the reference power supply current value of each power supply unit carried in the power supply correction instruction.
- the current power supply power of each power supply unit is the reference power supply power of each power supply unit, wherein the reference power supply power of each power supply unit is determined by the reference power supply current value of each power supply unit.
- the above-mentioned power adjustment module 82 is configured to determine the control correction amount of each of the above-mentioned power supply units according to the reference power supply current value of each of the above-mentioned power supply units and the current power supply state parameter;
- each power supply unit sends a power supply correction instruction to each of the above power supply units, so that each power supply unit adjusts the current power supply power of each power supply unit to the reference power supply power of each power supply unit according to the control correction amount of each power supply unit carried in the power supply correction instruction, wherein , the reference power supply power of each power supply unit is determined by the reference power supply current value of each power supply unit.
- the above-mentioned power adjustment module 82 is configured to determine the control correction amount of each of the above-mentioned power supply units according to the reference power supply current value of each of the above-mentioned power supply units and the current power supply state parameter;
- each power supply unit sends a power supply correction instruction to each of the above-mentioned power supply units, so that each power supply unit adjusts the current power supply power of each power supply unit to the reference power supply power of each power supply unit according to the target bus reference voltage of each power supply unit carried in the power supply correction instruction,
- the reference power supply power of each power supply unit is determined by the reference power supply current value of each power supply unit.
- the power adjustment module 82 is configured to determine the target bus reference voltage of each power supply unit based on the initial bus reference voltage, the control correction amount of each power supply unit, and the voltage correction amount of each power supply unit. , wherein the voltage correction amount of each power supply unit is determined based on the current power supply state parameter of each power supply unit and the virtual impedance of each power supply unit.
- the virtual impedance is determined based on the current power supply state parameter of the power supply unit.
- the above-mentioned power supply current control device is a first power supply unit among the above-mentioned at least two power supply units.
- the power supply unit includes a DC/DC converter or a DC/AC converter, wherein the DC/DC converter is used to adjust the current power supply of the DC/DC converter, and the DC/AC converter The controller is used to adjust the current supply power of the above-mentioned DC/AC converter.
- the power supply current control device 8 is used to implement the steps performed by the power supply current control device in the embodiment shown in FIG. 6 .
- the power supply current control device 8 can control the power supply current value of each power supply unit according to the current actual power supply capability of each power supply unit connected in parallel with the DC bus. Allocated to achieve reasonable load distribution among each power supply unit, thereby prolonging the service life of each power supply unit and reducing the operation and maintenance cost of the photovoltaic system.
- the DC/AC converter 9 may include: an acquisition determination module 91 and a power adjustment module 92 .
- the acquisition and determination module 91 is used to acquire the current output state parameters of the DC/DC converters in each power supply unit when the DC/AC converter is in the power-limited working mode, and according to the current output state of the DC/DC converters in each power supply unit The parameter determines the reference output current value of the DC/DC converter in each power supply unit;
- the power adjustment module 92 is configured to adjust the current output power of the DC/DC converter in each power supply unit according to the reference output current value of the DC/DC converter in each power supply unit.
- the above-mentioned DC/AC converter 9 further includes:
- the system power determination module 93 is configured to determine that the current output power of the photovoltaic system is greater than the system output power threshold.
- the current output state parameters of the DC/DC converters in each power supply unit include the current output power and current output capability of the DC/DC converters in each of the power supply units;
- the above-mentioned DC/AC converter 9 also includes:
- the current output power adjustment module 94 is configured to adjust the current output power of the DC/DC converters in the power supply units according to the current output power and the current output capability of the DC/DC converters in the power supply units, so as to avoid the photovoltaic system
- One of the DC/DC converters or part of the DC/DC converters works in the extreme working state.
- the current output state parameters of the DC/DC converters in each power supply unit include the current maximum output power of the DC/DC converters in each of the power supply units;
- the above acquisition and determination module 91 includes:
- the power ratio determination unit 911 is configured to determine, based on the current maximum output power of the DC/DC converter in each of the above-mentioned power supply units, the current maximum output power of the DC/DC converter in each of the above-mentioned power supply units in the at least two of the above-mentioned power supply units The proportion of the current maximum output power in the sum of the current maximum output power of the DC/DC converter;
- the reference current determination unit 912 is configured to determine the reference output current value of the DC/DC converter in each of the above-mentioned power supply units based on the above-mentioned current maximum output power ratio.
- the current output state parameters of the DC/DC converters in each power supply unit further include the current equipment operating condition parameters of the DC/DC converters in each power supply unit;
- the above-mentioned power ratio determination unit 911 is configured to determine the current corrected output power of the DC/DC converter in each of the above-mentioned power supply units based on the current equipment operating parameters and the current maximum output power of the DC/DC converter in each of the above-mentioned power supply units;
- the above-mentioned current corrected output power ratio is determined as the above-mentioned current maximum output power ratio.
- the power ratio determination unit 911 is configured to obtain the power attenuation coefficients corresponding to the current equipment operating parameters of the DC/DC converters in the power supply units, based on the DC/DC converters in the power supply units.
- the current maximum output power of the DC converter and the power attenuation coefficient determine the current corrected output power of the DC/DC converter in each of the above-mentioned power supply units.
- the current device operating condition parameter includes at least one of a current device temperature, a current device current stress, or a current device voltage stress.
- the current output state parameters of the DC/DC converters in the respective power supply units further include the current output currents of the DC/DC converters in the respective power supply units;
- the above-mentioned reference current determination unit 912 is configured to determine the reference of the DC/DC converter in each of the above-mentioned power supply units based on the above-mentioned current maximum output power ratio and the sum of the current output currents of the DC/DC converters in the above-mentioned at least two power supply units output current value.
- the DC/AC converter 9 is used to implement the steps performed by the DC/AC converter in the embodiment shown in FIG. 7 .
- the DC/AC converter when the output power of the photovoltaic system is greater than the system output power threshold, the DC/AC converter can perform the conversion to each DC/DC converter according to the current actual output capability of each DC/DC converter connected in parallel with the DC bus.
- the output current value of the converter is distributed, so as to realize the reasonable distribution of the load among the various DC/DC converters (that is, to achieve the output power balance between the various DC/DC converters), and avoid one of the various DC/DC converters.
- some DC/DC converters work in the limit power supply state, thereby extending the service life of each DC/DC converter and reducing the operation and maintenance cost of the photovoltaic system.
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Abstract
Description
Claims (30)
- 一种光伏系统,其特征在于,所述光伏系统包括直流母线、并联在所述直流母线的至少两个供电单元,以及通过所述直流母线与所述至少两个供电单元相连的DC/AC转换器,其中,所述至少两个供电单元中的各个供电单元均包括DC/DC转换器,所述DC/DC转换器的输入端与直流电源相连;所述DC/AC转换器,用于在所述DC/AC转换器处于限功率工作模式时,获取所述各个供电单元中DC/DC转换器的当前输出状态参数,根据所述各个供电单元中DC/DC转换器的当前输出状态参数确定所述各个供电单元中DC/DC转换器的参考输出电流值;根据各个供电单元中DC/DC转换器的参考输出电流值对所述各个供电单元中DC/DC转换器的当前输出功率进行调节。
- 根据权利要求1所述的光伏系统,其特征在于,所述DC/AC转换器还用于:确定所述光伏系统的当前输出功率大于系统输出功率阈值。
- 根据权利要求1所述的光伏系统,其特征在于,所述各个供电单元中DC/DC转换器的当前输出状态参数包括所述各个供电单元中DC/DC转换器的当前输出功率和当前输出能力;所述DC/AC转换器还用于:根据所述各个供电单元中DC/DC转换器的当前输出功率以及当前输出能力,调整所述各个供电单元中DC/DC转换器的当前输出功率,以避免所述光伏系统中的一个DC/DC转换器或者部分DC/DC转换器工作在极限工作状态。
- 根据权利要求1所述的方法,其特征在于,所述各个供电单元中DC/DC转换器的当前输出状态参数包括所述各个供电单元中DC/DC转换器的当前最大输出功率;所述根据所述各个供电单元中DC/DC转换器的当前输出状态参数确定所述各个供电单元中DC/DC转换器的参考输出电流值,包括:所述DC/AC转换器基于所述各个供电单元中DC/DC转换器的当前最大输出功率,确定所述各个供电单元中DC/DC转换器的当前最大输出功率在所述至少两个供电单元中DC/DC转换器的当前最大输出功率之和中的当前最大输出功率占比;基于所述当前最大输出功率占比确定所述各个供电单元中DC/DC转换器的参考输出电流值。
- 根据权利要求4所述的光伏系统,其特征在于,所述各个供电单元中DC/DC转换器的当前输出状态参数还包括所述各个供电单元中DC/DC转换器的当前设备工况参数;所述基于所述各个供电单元中DC/DC转换器的当前最大输出功率,确定所述各个供电单元中DC/DC转换器的当前最大输出功率在所述至少两个供电单元中DC/DC转换器的当前最大输出功率之和中的当前最大输出功率占比,包括:所述DC/AC转换器基于所述各个供电单元中DC/DC转换器的当前设备工况参数和当前最大输出功率,确定所述各个供电单元中DC/DC转换器的当前修正输出功率;基于所述各个供电单元中DC/DC转换器的当前修正输出功率,确定所述各个供电单元中DC/DC转换器的当前修正输出功率在所述至少两个供电单元中DC/DC转换器的当前修正输出功率之和中的当前修正输出功率占比;将所述当前修正输出功率占比确定为所述当前最大输出功率占比。
- 根据权利要求5所述的光伏系统,其特征在于,所述基于所述各个供电单元中DC/DC转换器的当前设备工况参数和当前最大输出功率,确定所述各个供电单元中DC/DC转换器的当前修正输出功率,包括:所述DC/AC转换器获取所述各个供电单元中DC/DC转换器的当前设备工况参数各自对应的功率衰减系数,基于所述各个供电单元中DC/DC转换器的当前最大输出功率以及功率衰减系数确定所述各个供电单元中DC/DC转换器的当前修正输出功率。
- 根据权利要求5或6所述的光伏系统,其特征在于,所述当前设备工况参数包括当前设备温度、当前设备电流应力或者当前设备电压应力中的至少一种。
- 根据权利要求4或5所述的光伏系统,其特征在于,所述各个供电单元中DC/DC转换器的当前输出状态参数还包括所述各个供电单元中DC/DC转换器的当前输出电流;所述基于所述当前最大输出功率占比确定所述各个供电单元中DC/DC转换器的参考输出电流值,包括:所述DC/AC转换器基于所述当前最大输出功率占比以及所述至少两个供电单元中DC/DC转换器的当前输出电流之和,确定所述各个供电单元中DC/DC转换器的参考输出电流值。
- 一种光伏系统,其特征在于,所述光伏系统包括直流母线、并联在所述直流母线的至少两个供电单元以及与所述至少两个供电单元建立有通信连接的系统控制单元;所述系统控制单元,用于获取所述至少两个供电单元中各个供电单元的当前供电状态参数,根据所述各个供电单元的当前供电状态参数确定所述各个供电单元的参考供电电流值;根据各个供电单元的参考供电电流值对所述各个供电单元的当前供电功率进行调节。
- 根据权利要求9所述的光伏系统,其特征在于,所述获取所述至少两个供电单元中各个供电单元的当前供电状态参数之前,还包括:所述系统控制单元确定所述光伏系统的当前输出功率大于系统输出功率阈值。
- 根据权利要求9所述的光伏系统,其特征在于,所述各个供电单元的当前供电状态参数包括所述各个供电单元的当前供电功率和当前供电能力;所述系统控制单元还用于:根据所述各个供电单元的当前供电功率以及当前供电能力,调整所述各个供电单元的当前供电功率,以避免所述至少两个供电单元中的一个供电单元或者部分供电单元工作在极限工作状态。
- 根据权利要求9所述的光伏系统,其特征在于,所述各个供电单元的当前供电状态参数包括所述各个供电单元的当前最大供电功率;所述根据所述各个供电单元的当前供电状态参数确定所述各个供电单元的参考供电电流值,包括:所述系统控制单元基于所述各个供电单元的当前最大供电功率,确定所述各个供电单元的当前最大供电功率在所述至少两个供电单元的当前最大供电功率之和中的当前最大供电功率占比;基于所述当前最大供电功率占比确定所述各个供电单元的参考供电电流值。
- 根据权利要求12所述的光伏系统,其特征在于,所述各个供电单元的当前供电状态参数还包括所述各个供电单元的当前设备工况参数;所述基于所述各个供电单元的当前最大供电功率,确定所述各个供电单元的当前最大供电功率在所述至少两个供电单元的当前最大供电功率之和中的当前最大供电功率占比,包括:所述系统控制单元基于所述各个供电单元的当前设备工况参数和当前最大供电功率,确定所述各个供电单元的当前修正供电功率;基于所述各个供电单元的当前修正供电功率,确定所述各个供电单元的当前修正供电功率在所述至少两个供电单元的当前修正供电功率之和中的当前修正供电功率占比;将所述当前修正供电功率占比确定为所述当前最大供电功率占比。
- 根据权利要求13所述的光伏系统,其特征在于,所述基于所述各个供电单元的当前设备工况参数和当前最大供电功率,确定所述各个供电单元的当前修正供电功率,包括:所述系统控制单元获取所述各个供电单元的当前设备工况参数各自对应的功率衰减系数,基于所述各个供电单元的当前最大供电功率以及功率衰减系数确定所述各个供电单元的当前修正供电功率。
- 根据权利要求13或14所述的光伏系统,其特征在于,所述当前设备工况参数包括当前设备温度、当前设备电流应力或者当前设备电压应力中的至少一种。
- 根据权利要求12或13所述的光伏系统,其特征在于,所述各个供电单元的当前供电状态参数还包括所述各个供电单元的当前供电电流;所述基于所述当前供电功率占比确定所述各个供电单元的参考供电电流值,包括:所述系统控制单元基于所述当前最大供电功率占比以及所述至少两个供电单元的当前供电电流之和,确定所述各个供电单元的参考供电电流值。
- 根据权利要求9所述的光伏系统,其特征在于,所述根据各个供电单元的参考供电电流值对所述各个供电单元的当前供电功率进行调节,包括:所述系统控制单元向所述各个供电单元发送供电功率修正指令,以使各个供电单元根据供电功率修正指令中携带的各个供电单元的参考供电电流值,调节各个供电单元的当前供电功率为各个供电单元的参考供电功率,其中,所述各个供电单元的参考供电功率由所述各个供电单元的参考供电电流值确定。
- 根据权利要求9所述的光伏系统,其特征在于,所述根据各个供电单元的参考供电电流值对所述各个供电单元的当前供电功率进行调节,包括:所述系统控制单元根据所述各个供电单元的参考供电电流值和当前供电状态参数确定所述各个供电单元的控制修正量;所述系统控制单元向所述各个供电单元发送供电功率修正指令,以使各个供电单元根据供电功率修正指令中携带的各个供电单元的控制修正量,调节各个供电单元的当前供电功率为各个供电单元的参考供电功率,其中,所述各个供电单元的参考供电功率由所述各个供电单元的参考供电电流值确定。
- 根据权利要求9所述的光伏系统,其特征在于,所述根据各个供电单元的参考供电电流值对所述各个供电单元的当前供电功率进行调节,包括:所述系统控制单元根据所述各个供电单元的参考供电电流值和当前供电状态参数确定所述各个供电单元的控制修正量;根据初始母线参考电压和所述各个供电单元的控制修正量确定所述各个供电单元的目标母线参考电压;向所述各个供电单元发送供电功率修正指令,以使各个供电单元根据供电功率修正指令中携带的各个供电单元的目标母线参考电压,调节各个供电单元的当前供电功率为各个供电单元的参考供电功率,其中,所述各个供电单元的参考供电功率由所述各个供电单元的参考供电电流值确定。
- 根据权利要求19所述的光伏系统,其特征在于,所述根据初始母线参考电压和所述各个供电单元的控制修正量确定所述各个供电单元的目标母线参考电压,包括:所述系统控制单元基于所述初始母线参考电压、所述各个供电单元的控制修正量和所述各个供电单元的电压修正量确定所述各个供电单元的目标母线参考电压,其中,所述各个供电单元的电压修正量是基于所述各个供电单元的当前供电状态参数和所述各个供电单元的虚拟阻抗确定。
- 根据权利要求9所述的光伏系统,其特征在于,所述至少两个供电单元中的第一供电单元包括所述系统控制单元。
- 根据权利要求9-21所述的光伏系统,其特征在于,所述供电单元包括DC/DC转换器或者DC/AC转换器,其中,所述DC/DC转换器用于调节所述DC/DC转换器的当前供电功率,所述DC/AC转换器用于调节所述DC/AC转换器的当前供电功率。
- 一种光伏系统的供电电流控制方法,其特征在于,所述光伏系统包括直流母线、并联在所述直流母线的至少两个供电单元,以及通过所述直流母线与所述至少两个供电单元相连的DC/AC转换器,其中,所述至少两个供电单元中的各个供电单元均包括DC/DC转换器,所述DC/DC转换器的输入端与直流电源相连;所述DC/AC转换器在所述DC/AC转换器处于限功率工作模式时,获取所述各个供电单元中DC/DC转换器的当前输出状态参数,根据所述各个供电单元中DC/DC转换器的当前输出状态参数确定所述各个供电单元中DC/DC转换器的参考输出电流值;根据各个供电单元中DC/DC转换器的参考输出电流值对所述各个供电单元中DC/DC转换器的当前输出功率进行调节。
- 根据权利要求23所述的方法,其特征在于,所述各个供电单元中DC/DC转换器的当前输出状态参数包括所述各个供电单元中DC/DC转换器的当前输出功率和当前输出能力;所述方法还包括:所述DC/AC转换器根据所述各个供电单元中DC/DC转换器的当前输出功率以及当前输出能力,调整所述各个供电单元中DC/DC转换器的当前输出功率,以避免所述光伏系统中的一个DC/DC转换器或者部分DC/DC转换器工作在极限工作状态。
- 根据权利要求23所述的方法,其特征在于,所述各个供电单元中DC/DC转换器的当前输出状态参数包括所述各个供电单元中DC/DC转换器的当前最大输出功率;所述根据所述各个供电单元中DC/DC转换器的当前输出状态参数确定所述各个供电单元中DC/DC转换器的参考输出电流值,包括:所述DC/AC转换器基于所述各个供电单元中DC/DC转换器的当前最大输出功率,确定所述各个供电单元中DC/DC转换器的当前最大输出功率在所述至少两个供电单元中DC/DC转换器的当前最大输出功率之和中的当前最大输出功率占比;基于所述当前最大输出功率占比确定所述各个供电单元中DC/DC转换器的参考输出电流值。
- 根据权利要求25所述的方法,其特征在于,所述各个供电单元中DC/DC转换器的当前输出状态参数还包括所述各个供电单元中DC/DC转换器的当前设备工况参数;所述基于所述各个供电单元中DC/DC转换器的当前最大输出功率,确定所述各个供电单元中DC/DC转换器的当前最大输出功率在所述至少两个供电单元中DC/DC转换器的当前最大输出功率之和中的当前最大输出功率占比,包括:所述DC/AC转换器基于所述各个供电单元中DC/DC转换器的当前设备工况参数和当前最大输出功率,确定所述各个供电单元中DC/DC转换器的当前修正输出功率;基于所述各个供电单元中DC/DC转换器的当前修正输出功率,确定所述各个供电单元中DC/DC转换器的当前修正输出功率在所述至少两个供电单元中DC/DC转换器的当前修正输出功率之和中的当前修正输出功率占比;将所述当前修正输出功率占比确定为所述当前最大输出功率占比。
- 一种光伏系统的供电电流控制方法,其特征在于,所述光伏系统包括直流母线和并联在所述直流母线的至少两个供电单元;所述方法包括:获取所述至少两个供电单元中各个供电单元的当前供电状态参数,根据所述各个供电单元的供电状态参数确定所述各个供电单元的参考供电电流值;根据各个供电单元的参考供电电流值对所述各个供电单元的当前供电功率进行调节。
- 根据权利要求27所述的方法,其特征在于,所述各个供电单元的当前供电状态参数包括所述各个供电单元的当前供电功率和当前供电能力;所述方法还包括:根据所述各个供电单元的当前供电功率以及当前供电能力,调整所述各个供电单元的当前供电功率,以避免所述至少两个供电单元中的一个供电单元或者部分供电单元工作在极限工作状态。
- 根据权利要求27所述的方法,其特征在于,所述各个供电单元的当前供电状态参数包括所述各个供电单元的当前最大供电功率;所述根据所述各个供电单元的当前供电状态参数确定所述各个供电单元的参考供电电流值,包括:基于所述各个供电单元的当前最大供电功率,确定所述各个供电单元的当前最大供电功率在所述至少两个供电单元的当前最大供电功率之和中的当前最大供电功率占比;基于所述当前最大供电功率占比确定所述各个供电单元的参考供电电流。
- 根据权利要求29所述的方法,其特征在于,所述各个供电单元的当前供电状态参数还包括所述各个供电单元的当前设备工况参数;所述基于所述各个供电单元的当前最大供电功率,确定所述各个供电单元的当前最大供电功率在所述至少两个供电单元的当前最大供电功率之和中的当前最大供电功率占比,包括:基于所述各个供电单元的设备工况参数和当前最大供电功率,确定所述各个供电单元的当前修正供电功率;基于所述各个供电单元的当前修正供电功率,确定所述各个供电单元的当前修正供电功率在所述至少两个供电单元的当前修正供电功率之和中的当前修正供电功率占比;将所述当前修正供电功率占比确定为所述当前最大供电功率占比。
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