WO2023272579A1 - 一种直流母线电压的控制系统和控制方法 - Google Patents

一种直流母线电压的控制系统和控制方法 Download PDF

Info

Publication number
WO2023272579A1
WO2023272579A1 PCT/CN2021/103500 CN2021103500W WO2023272579A1 WO 2023272579 A1 WO2023272579 A1 WO 2023272579A1 CN 2021103500 W CN2021103500 W CN 2021103500W WO 2023272579 A1 WO2023272579 A1 WO 2023272579A1
Authority
WO
WIPO (PCT)
Prior art keywords
bus voltage
voltage
value
bus
grid
Prior art date
Application number
PCT/CN2021/103500
Other languages
English (en)
French (fr)
Inventor
曹元峥
李琳
郭海滨
Original Assignee
华为数字能源技术有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 华为数字能源技术有限公司 filed Critical 华为数字能源技术有限公司
Priority to EP21947533.2A priority Critical patent/EP4344010A1/en
Priority to PCT/CN2021/103500 priority patent/WO2023272579A1/zh
Priority to CN202180099004.8A priority patent/CN117461233A/zh
Publication of WO2023272579A1 publication Critical patent/WO2023272579A1/zh
Priority to US18/398,776 priority patent/US20240128745A1/en

Links

Images

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H02J3/381—Dispersed generators
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J1/00—Circuit arrangements for dc mains or dc distribution networks
    • H02J1/06—Two-wire systems
    • 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
    • H02J3/388—Islanding, i.e. disconnection of local power supply from the network
    • 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
    • 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 embodiments of the present application relate to the technical field of power supplies, and in particular to a control system and method for DC bus voltage.
  • the inverter can be connected to the power grid and load equipment respectively, for example, the inverter can be a photovoltaic grid-connected inverter.
  • the output terminal of the inverter is directly connected to the grid through a common connection point, and other load equipment may be connected to the output terminal. After the output terminal is connected to the grid, the port voltage of the output terminal is clamped by the grid, and the port voltage amplitude is determined by the grid voltage Size decides.
  • control scheme for DC bus voltage can only be applied to high voltage ride-through scenarios, or can only be applied to grid-disconnected operation scenarios, that is, the current control scheme for DC bus voltage cannot be applied to the above two scenarios at the same time.
  • how to control the DC bus voltage under the two scenarios of compatibility with high voltage ride-through and instant grid-off operation is an urgent problem to be solved.
  • the embodiment of the present application provides a DC bus voltage control system and control method, which are used to control the DC bus voltage in the two scenarios of compatibility with high voltage ride-through and power grid interruption operation, and control the DC bus voltage at within a reasonable range.
  • the embodiment of the present application provides a DC bus voltage control system, including: a controller and an inverter;
  • the output end of the inverter is connected to the grid, and the input end of the inverter is connected to the photovoltaic module through a DC bus;
  • the controller is used to obtain grid voltage
  • the second DC bus voltage reference value is obtained according to the first DC bus voltage reference value and the preset first rising gradient value, so as to limit the rising rate of the DC bus voltage.
  • the DC bus voltage raised by the backfeeding of the grid during the detection period of the grid voltage jump is sufficient to support the subsequent high-voltage ride-through power output; if
  • the second DC bus voltage reference value is obtained according to the first DC bus voltage reference value and the preset first rising gradient value.
  • the preset first rising gradient value The value can limit the rising rate of the DC bus voltage, so that the rising amount of the DC bus voltage will be reduced during the period of detection of the grid voltage jump, so the embodiment of the present application can be compatible with both high voltage ride-through and the moment of grid failure operation. In this scenario, the control of the DC bus voltage is realized.
  • the controller is further configured to: acquire a third DC bus voltage reference value according to the second DC bus voltage reference value and a preset second rising gradient value, wherein the The second ascending gradient value is smaller than the first ascending gradient value.
  • the rising gradient of the DC bus voltage reference value is reduced from the first rising gradient value to the second rising gradient value.
  • the controller is further configured to: adjust the sampled maximum value of the DC bus voltage according to a preset voltage amplitude threshold, so as to obtain the first reference value of the DC bus voltage.
  • the controller in the embodiment of the present application can quickly increase the sampled maximum value of the DC bus voltage when the grid voltage jumps, so as to obtain the first reference value of the DC bus voltage, so that the DC bus voltage can be quickly raised.
  • the controller can quickly increase the sampled maximum value of the DC bus voltage when the grid voltage jumps, so as to obtain the first reference value of the DC bus voltage, so that the DC bus voltage can be rapidly raised.
  • the controller is further configured to: determine the voltage amplitude threshold according to a DC bus voltage value to be used when the inverter performs high voltage ride through.
  • the voltage amplitude threshold can be used to adjust the maximum sampling value of the DC bus voltage to obtain the first DC bus voltage reference value.
  • the voltage amplitude threshold is specifically the DC bus voltage value that needs to be used when the inverter performs high-voltage ride-through , if the maximum sampling value of the DC bus voltage cannot meet the DC bus voltage value required by the inverter for HRT For the DC bus voltage value that needs to be used during high voltage ride-through, it is necessary to set the threshold value of the voltage amplitude to be small or zero.
  • the voltage amplitude threshold is a voltage value greater than 0 or equal to 0.
  • the voltage amplitude threshold may be expressed as ⁇ U, and the value of ⁇ U may be greater than 0 or equal to 0.
  • ⁇ U it is necessary to ensure that the raised DC BUS voltage reference value can meet the voltage value required for high wear; after the normal grid voltage jumps, there will be BUS voltage backfeeding for a short time, that is, the energy of the grid is poured back into the DC bus , causing the BUS voltage to rise passively.
  • the actual value of the BUS voltage after passive lifting is high enough for high wear, adjust the value of ⁇ U.
  • ⁇ U is equal to 0. If the maximum value of the DC bus voltage sampling is not enough for high wear, then ⁇ U needs to be greater than 0, so that the DC bus voltage reference value can meet the voltage value used during high wear.
  • the specific value of ⁇ U is not limited here.
  • the controller is further configured to: When the inverter conforms to the grid disconnection feature, the grid disconnection operation is performed on the inverter.
  • the controller can also detect whether the inverter conforms to the grid-off feature. When the inverter meets the grid-off feature, the controller performs the grid-off operation on the inverter, so it is suitable for inverter grid outage scenario.
  • the characteristics of the outage grid may include: high grid voltage peak value, grid frequency fluctuation, and continuous over-modulation.
  • the controller is further configured to: when the inverter satisfies a preset protection shutdown condition, control the The inverter is shut down.
  • the protection shutdown condition refers to the judgment condition of whether the inverter needs to be protected and shut down.
  • the controller is further configured to: when the inverter does not meet the protection shutdown condition, trigger a restart Steps to get grid voltage.
  • the protection shutdown condition refers to the judgment condition of whether the inverter needs to be protected and shut down.
  • the first rising gradient value is a 1 V/ms; wherein, the V/ms represents the rising gradient value in units of volts per millisecond.
  • the value of a1 can be reduced to limit the rate of rise of the DC bus voltage, so that the amount of rise of the DC bus voltage will be reduced during the period of detection of grid voltage jumps, so the embodiment of the present application can At the same time, it is compatible with the two scenarios of high-voltage ride-through and momentary power-off operation, and realizes the control of the DC bus voltage.
  • the a 1 satisfies the following relationship: b ⁇ a 1 ⁇ y/x; wherein, the b represents the saturation speed for controlling the DC bus voltage reference value, and the y represents the The maximum allowable magnitude of the DC bus voltage, and the x represents the protection time required by the operating overvoltage.
  • the rising gradient value of the DC bus voltage reference value can represent a, for example, the value of a can include various values, such as a 1 , the setting of the rising gradient aV/ms value can be based on the bus in the controller
  • the voltage reference calculation module is realized, and the bus voltage reference calculation module includes the saturation speed of the controller, assuming that the saturation speed of the controller (such as a PI regulator) of the bus voltage reference calculation module is bV/ms, and the protection time required by the operation overvoltage is xms , the maximum allowable rise of the BUS voltage during this period is y V, then the value of a satisfies the following relationship: b ⁇ a ⁇ y/x, so the value of a can be determined through the above relationship.
  • the controller is further configured to: respectively obtain the peak value of the grid voltage and the effective value of the grid voltage; It is judged whether the grid voltage jumps.
  • the controller may include a sampling circuit, through which the grid voltage sampling value can be obtained, so that the peak value of the grid voltage and the effective value of the grid voltage can be calculated, and finally the grid voltage can be judged according to the calculated peak value and effective value Whether it jumps or not realizes the judgment of whether the grid voltage jumps or not.
  • the controller is further configured to: When the inverter conforms to the high voltage ride-through feature, the output power of the inverter is controlled to increase.
  • the maximum value of the BUS voltage sampled in Tres is calculated, and ⁇ U is added, which is used as the reference value of the BUS voltage;
  • the BUS voltage is sufficient to support the subsequent high-throughput power output; if the power grid is cut off, the BUS voltage increase in Tres is still within a reasonable range, for example, the reasonable range is that the BUS voltage has not reached the overvoltage point; first raise the BUS voltage reference value to ensure Functional output, and then make feature judgments to identify high wear.
  • the feature judgment refers to identifying the characteristics of the disconnected grid or the high wear-through feature.
  • the feature identification can be to obtain the characteristics of the grid voltage, grid frequency, and modulation ratio. In the embodiment of this application, the characteristics of the inverter that need to be obtained are not done limited.
  • the embodiment of the present application provides a DC bus voltage control method, including: obtaining grid voltage, the output terminal of the inverter is connected to the grid, and the input terminal of the inverter is connected to the photovoltaic module through the DC bus; When the grid voltage jumps, acquire the maximum value of the DC bus voltage sampling of the inverter, and the maximum value of the DC bus voltage sampling is the maximum value of the voltage on the DC bus during the time period when the grid voltage jump is detected; Obtain a first DC bus voltage reference value according to the sampled maximum value of the DC bus voltage, wherein the DC bus voltage reference value is greater than or equal to the sampled maximum value of the DC bus voltage; according to the first DC bus voltage reference value and the preset first rising gradient value to obtain a second DC bus voltage reference value, so as to limit the rising rate of the DC bus voltage.
  • the DC bus voltage raised by the backfeeding of the grid during the detection period of the grid voltage jump is sufficient to support the subsequent high-voltage ride-through power output; if
  • the second DC bus voltage reference value is obtained according to the first DC bus voltage reference value and the preset first rising gradient value.
  • the preset first rising gradient value The value can limit the rising rate of the DC bus voltage, so that the rising amount of the DC bus voltage will be reduced during the period of detection of the grid voltage jump, so the embodiment of the present application can be compatible with both high voltage ride-through and the moment of grid failure operation. In this scenario, the control of the DC bus voltage is realized.
  • the method further includes: acquiring a third DC bus voltage reference value according to the second DC bus voltage reference value and a preset second rising gradient value, wherein the second rising The gradient value is smaller than the first ascending gradient value.
  • the rising gradient of the DC bus voltage reference value is reduced from the first rising gradient value to the second rising gradient value.
  • the acquiring the first DC bus voltage reference value according to the sampled maximum value of the DC bus voltage includes: adjusting the sampled maximum value of the DC bus voltage according to a preset voltage amplitude threshold to Obtain the first DC bus voltage reference value.
  • the controller in the embodiment of the present application can quickly increase the sampled maximum value of the DC bus voltage when the grid voltage jumps, so as to obtain the first reference value of the DC bus voltage, so that the DC bus voltage can be quickly raised.
  • the controller can quickly increase the sampled maximum value of the DC bus voltage when the grid voltage jumps, so as to obtain the first reference value of the DC bus voltage, so that the DC bus voltage can be rapidly raised.
  • the method further includes: determining the voltage amplitude threshold according to a DC bus voltage value to be used when the inverter performs high voltage ride through.
  • the voltage amplitude threshold can be used to adjust the maximum sampling value of the DC bus voltage to obtain the first DC bus voltage reference value.
  • the voltage amplitude threshold is specifically the DC bus voltage value that needs to be used when the inverter performs high-voltage ride-through , if the maximum sampling value of the DC bus voltage cannot meet the DC bus voltage value required by the inverter for HRT For the DC bus voltage value that needs to be used during high voltage ride-through, it is necessary to set the threshold value of the voltage amplitude to be small or zero.
  • the voltage amplitude threshold is a voltage value greater than 0 or equal to 0.
  • the voltage amplitude threshold may be expressed as ⁇ U, and the value of ⁇ U may be greater than 0 or equal to 0.
  • ⁇ U it is necessary to ensure that the raised DC BUS voltage reference value can meet the voltage value required for high wear; after the normal grid voltage jumps, there will be BUS voltage backfeeding for a short time, that is, the energy of the grid is poured back into the DC bus , causing the BUS voltage to rise passively.
  • the actual value of the BUS voltage after passive lifting is high enough for high wear, adjust the value of ⁇ U.
  • ⁇ U is equal to 0. If the maximum value of the DC bus voltage sampling is not enough for high wear, then ⁇ U needs to be greater than 0, so that the DC bus voltage reference value can meet the voltage value used during high wear.
  • the specific value of ⁇ U is not limited here.
  • the method further includes: when the When the inverter conforms to the grid disconnection feature, the grid disconnection operation is performed on the inverter.
  • the controller can also detect whether the inverter conforms to the grid-off feature. When the inverter meets the grid-off feature, the controller performs the grid-off operation on the inverter, so it is suitable for inverter grid outage scenario.
  • the characteristics of the outage grid may include: high grid voltage peak value, grid frequency fluctuation, and continuous over-modulation.
  • the method further includes: when the inverter satisfies a preset protection shutdown condition, controlling the inverter to shut down the device.
  • the protection shutdown condition refers to the judgment condition of whether the inverter needs to be protected and shut down.
  • the method further includes: when the inverter does not meet the protection shutdown condition, triggering to reacquire the grid voltage A step of.
  • the protection shutdown condition refers to the judgment condition of whether the inverter needs to be protected and shut down.
  • the first rising gradient value is a 1 V/ms, wherein the V/ms indicates that the unit of the rising gradient value is volts per millisecond.
  • the value of a1 can be reduced to limit the rate of rise of the DC bus voltage, so that the amount of rise of the DC bus voltage will be reduced during the period of detection of grid voltage jumps, so the embodiment of the present application can At the same time, it is compatible with the two scenarios of high-voltage ride-through and momentary power-off operation, and realizes the control of the DC bus voltage.
  • the a 1 satisfies the following relationship: b ⁇ a 1 ⁇ y/x, wherein the b represents the saturation speed for controlling the reference value of the DC bus voltage, and the y represents the The maximum allowable magnitude of the DC bus voltage, and the x represents the protection time required by the operating overvoltage.
  • the rising gradient value of the DC bus voltage reference value can represent a, for example, the value of a can include various values, such as a 1 , the setting of the rising gradient aV/ms value can be based on the bus in the controller
  • the voltage reference calculation module is realized, and the bus voltage reference calculation module includes the saturation speed of the controller, assuming that the saturation speed of the controller (such as a PI regulator) of the bus voltage reference calculation module is bV/ms, and the protection time required by the operation overvoltage is xms , the maximum allowable rise of the BUS voltage during this period is y V, then the value of a satisfies the following relationship: b ⁇ a ⁇ y/x, so the value of a can be determined through the above relationship.
  • the method further includes: acquiring the peak value of the grid voltage and the effective value of the grid voltage respectively; judging the Whether the grid voltage jumps.
  • the controller may include a sampling circuit, through which the grid voltage sampling value can be obtained, so that the peak value of the grid voltage and the effective value of the grid voltage can be calculated, and finally the grid voltage can be judged according to the calculated peak value and effective value Whether it jumps or not realizes the judgment of whether the grid voltage jumps or not.
  • the method further includes: when the When the inverter conforms to the high voltage ride-through feature, the output power of the inverter is controlled to increase.
  • the maximum value of the BUS voltage sampled in Tres is calculated, and ⁇ U is added to take it as the reference value of the BUS voltage;
  • the BUS voltage is sufficient to support the subsequent high-throughput power output; if the power grid is cut off, the BUS voltage increase in Tres is still within a reasonable range, for example, the reasonable range is that the BUS voltage has not reached the overvoltage point; first raise the BUS voltage reference value to ensure Functional output, and then make feature judgments to identify high wear.
  • the feature judgment refers to identifying the characteristics of the disconnected grid or the high wear-through feature.
  • the feature identification can be to obtain the characteristics of the grid voltage, grid frequency, and modulation ratio. In the embodiment of this application, the characteristics of the inverter that need to be obtained are not done limited.
  • the first DC bus voltage reference value is obtained according to the maximum value of the DC bus voltage sampling, and the maximum value of the DC bus voltage is sampled according to Obtain the first DC bus voltage reference value, the DC bus voltage reference value is greater than or equal to the sampling maximum value of the DC bus voltage; if the inverter has a high voltage ride through (referred to as high voltage ride through), during the time period of detecting the grid voltage jump The DC bus voltage raised by the backfeeding of the internal grid is sufficient to support the subsequent high-throughput power output; if the inverter is disconnected from the grid, it can be obtained according to the first DC bus voltage reference value and the preset first rising gradient value.
  • the second DC bus voltage reference value in the embodiment of the present application, the rising rate of the DC bus voltage can be limited by the preset first rising gradient value, so that the rising amount of the DC bus voltage will be reduced during the time period for detecting grid voltage jumps. Therefore, the embodiment of the present application can simultaneously be compatible with the two scenarios of high voltage ride-through and operation moment when the power grid is cut off, and realizes the control of the DC bus voltage.
  • FIG. 1 is a schematic diagram of the composition and structure of a control system for a DC bus voltage provided in an embodiment of the present application;
  • FIG. 2 is a schematic diagram of an implementation manner of a control function performed by a controller provided in an embodiment of the present application;
  • FIG. 3 is a schematic diagram of the relationship between the actual value of the DC bus voltage and the reference value of the DC bus voltage provided by the embodiment of the present application;
  • FIG. 4 is a schematic diagram of the composition and structure of a two-stage inverter provided in the embodiment of the present application.
  • FIG. 5 is a schematic diagram of an application scenario of a control function of a controller provided in an embodiment of the present application.
  • the embodiment of the present application provides a DC bus voltage control system and control method, which are used to control the DC bus voltage in the two scenarios of compatibility with high voltage ride-through and power grid interruption operation, and control the DC bus voltage at within a reasonable range.
  • the embodiment of the present application provides a DC bus voltage control system
  • the control system 100 includes: a controller 101 and an inverter 102, wherein,
  • the controller 101 is connected to the inverter 102;
  • the controller 101 is configured to obtain the grid voltage input from the grid to the inverter 102, and the output terminal of the inverter 102 is connected to the grid; when the grid voltage jumps, obtain the grid voltage of the inverter 102
  • the maximum sampling value of the DC bus voltage is the maximum voltage value on the DC bus during the time period for detecting grid voltage jumps;
  • the DC bus voltage reference value is determined according to the sampling maximum value of the DC bus voltage, wherein, The DC bus voltage reference value is greater than or equal to the sampled maximum value of the DC bus voltage; a second DC bus voltage reference value is obtained according to the first DC bus voltage reference value and a preset first rising gradient value, so as to limit The rate of rise of the DC bus voltage.
  • the controller 101 provided in the embodiment of the present application may be a control device independent of the inverter 102, and the controller 101 may also be a control unit in the inverter 102, which is not limited here.
  • the inverter 102 provided in the embodiment of the present application may specifically be a photovoltaic inverter, for example, the inverter may be a photovoltaic grid-connected inverter.
  • the inverter 102 may include at least two converters, for example, the inverter 102 may include a DC/DC converter (direct-current/direct-current converter, DC/DC), and a DC/AC converter (direct-current/ alternating-current converter, DC/AC).
  • the DC/DC converter in the embodiment of the present application may include but not limited to an asymmetrical half-bridge flyback converter, an asymmetrical half-bridge forward converter, an LLC resonant converter, and the like.
  • the controller provided in the embodiment of the present application is used for:
  • the controller may specifically be a control device independent of the inverter, and the controller may also be a control unit in the inverter.
  • the controller may include a sampling circuit inside the inverter, through which the grid voltage is sampled.
  • the controller is independent of the inverter, and the controller interacts with the inverter to obtain the grid voltage.
  • the output end of the inverter is connected to the grid
  • the input end of the inverter is connected to the photovoltaic module through a DC bus
  • the photovoltaic (photovoltaic, PV) module is used as a DC source
  • a grid can be set between the output end and the grid.
  • the side switch when the inverter is normally connected to the grid, the grid side switch can be turned off, suddenly disconnecting the AC side grid.
  • the controller can determine whether a grid voltage jump occurs.
  • the controller can obtain the maximum value of the DC bus voltage sampling of the inverter.
  • the time period for detecting grid voltage jumps is denoted as Tres, and the specific value of Tres and the starting time point of Tres are not limited here.
  • the subsequent DC bus voltage may also be referred to as BUS voltage.
  • the controller is also used for:
  • the controller may include a sampling circuit, through which the sampling value of the grid voltage can be obtained, so that the peak value of the grid voltage and the effective value of the grid voltage can be calculated, and finally whether the grid voltage jumps is judged according to the calculated peak value and the effective value , to realize the judgment of whether the grid voltage jumps.
  • the controller obtains the first DC bus voltage reference value according to the sampled maximum value of the DC bus voltage, and it only needs to meet that the first DC bus voltage reference value is greater than or equal to It is sufficient to sample the maximum value of the voltage, and the specific value of the first DC bus voltage reference value is not limited here.
  • the maximum sampled value of the DC bus voltage is used as the base value, the base value is adjusted according to a preset voltage amplitude threshold, and the adjusted voltage value is used as the first DC bus voltage reference value.
  • the first DC bus voltage reference value is greater than or equal to the sampled maximum value of the DC bus voltage, and the specific value of the first DC bus voltage reference value is not limited here.
  • obtaining the first DC bus voltage reference value according to the maximum value of the DC bus voltage samples includes:
  • the controller can rapidly increase the sampled maximum value of the DC bus voltage when the grid voltage jumps, so as to obtain the first reference value of the DC bus voltage, so that the DC bus voltage can be rapidly increased.
  • adjusting the maximum sampling value of the DC bus voltage according to a preset voltage amplitude threshold to obtain a first reference value of the DC bus voltage includes:
  • the first DC bus voltage reference value is obtained in the following manner:
  • U BUS-R represents the first DC bus voltage reference value
  • U BUS-MAX represents the maximum sampling value of the DC bus voltage
  • ⁇ U represents the voltage amplitude threshold
  • the voltage amplitude threshold can be expressed as ⁇ U, and the value of ⁇ U can be determined in combination with the application scenario. There is no limitation on the way of determining the value of ⁇ U here.
  • the controller is also used for:
  • the voltage amplitude threshold can be used to adjust the maximum sampling value of the DC bus voltage to obtain the first DC bus voltage reference value.
  • the voltage amplitude threshold is specifically determined by the DC bus voltage value that needs to be used when the inverter performs high-voltage ride-through. If If the maximum sampling value of the DC bus voltage cannot meet the DC bus voltage value required for the inverter to perform high-voltage ride-through, it is necessary to set a larger threshold for the voltage amplitude.
  • the DC bus voltage value that needs to be used during crossing needs to be set to a smaller or zero voltage amplitude threshold.
  • the voltage magnitude threshold is a voltage value greater than or equal to zero.
  • the voltage amplitude threshold may be expressed as ⁇ U, and the value of ⁇ U may be greater than 0 or equal to 0. Specifically, it is necessary to ensure that the raised DC BUS voltage reference value can meet the voltage value required for high wear; after the normal grid voltage jumps, there will be BUS voltage backfeeding for a short time, that is, the energy of the grid is poured back into the DC bus , causing the BUS voltage to rise passively. When the actual value of the BUS voltage after passive lifting is high enough for high wear, adjust the value of ⁇ U. At this time, ⁇ U is equal to 0. If the maximum value of the DC bus voltage sampling is not enough for high wear, then ⁇ U needs to be greater than 0, so that the DC bus voltage reference value can meet the voltage value used during high wear. The specific value of ⁇ U is not limited here.
  • the controller after the controller obtains the first DC bus voltage reference value at the current moment, it can also obtain the DC bus voltage reference value at other times after the current moment according to the first DC bus voltage reference value and the preset rising gradient value.
  • value for example, preset a rising gradient value of the DC bus voltage reference value at each moment, the value of the rising gradient value is reduced, and reducing the rising gradient value of the DC bus voltage reference value can limit the DC bus voltage The rising rate slows down the rise of the DC bus voltage.
  • the controller is also used for:
  • the third DC bus voltage reference value is obtained according to the second DC bus voltage reference value and a preset second rising gradient value, wherein the second rising gradient value is smaller than the first rising gradient value.
  • the controller after the controller acquires the first DC bus voltage reference value at the current moment, it can also sequentially acquire the DC bus voltage at other times after the current moment according to the first DC bus voltage reference value and the preset rising gradient value
  • the reference value for example, an ascending gradient value of the reference value of the DC bus voltage is preset at each moment, and the changing trend of the ascending gradient value is successively decreasing. Reducing the rising gradient value of the DC bus voltage reference value can limit the rising rate of the DC bus voltage, making the rise of the DC bus voltage slower.
  • the second DC bus voltage reference value is to obtain the third DC bus voltage reference value at the next moment according to the second DC bus voltage reference value and the preset second rising gradient value, wherein the second rising gradient value is smaller than the first rising gradient value Gradient value, so in the embodiment of this application, the rising rate of the BUS voltage is limited by setting the rising gradient of the BUS voltage reference value, because the control variable is the BUS voltage, the actual value of the BUS voltage must track the BUS voltage reference value, and limit the reference value
  • the rising gradient can limit the rising rate of the actual value of the BUS voltage.
  • the DC bus voltage reference value may also be referred to as a BUS voltage reference value, or a lower limit of the BUS voltage reference value.
  • the controller is further configured to:
  • the grid disconnection operation is performed on the inverter.
  • the controller can also detect whether the inverter conforms to the characteristics of disconnecting the grid.
  • the controller performs the grid disconnection operation on the inverter, so it is applicable to Web scene.
  • the grid outage characteristics may include: high grid voltage peaks, grid frequency fluctuations, and continuous overmodulation.
  • the rise of the voltage of the AC port can be suppressed, that is, modulated according to a fixed modulation ratio, the lower the BUS voltage, the lower the voltage of the modulated AC port; Before the feature detection and recognition, the BUS voltage rise is limited to buy time for the protection action.
  • the controller is also used to:
  • the inverter When the inverter meets the preset protective shutdown conditions, the inverter is controlled to shut down.
  • the protective shutdown condition refers to the judging condition of whether the inverter needs to be protected.
  • the preset protection shutdown conditions are met, the inverter is shut down for protection, and at this time, the inverter is shut down under the control of the controller and stops running.
  • the controller is also used to:
  • step 201 of re-obtaining the grid voltage is triggered.
  • the protective shutdown condition refers to the judging condition of whether the inverter needs to be protected.
  • the protection shutdown condition is not satisfied, re-execute steps 201 to 204.
  • the first rising gradient value is a 1 V/ms, wherein the V/ms means that the unit of the rising gradient value is volts per millisecond.
  • the first rising gradient value is a 1 V/ms
  • the second rising gradient value is a 2 V/ms
  • the a 1 and the a 2 satisfy the following relationship: a 2 ⁇ a 1
  • the V/ms represents the rising gradient value in units of volts per millisecond.
  • the second rising gradient value is smaller than the first rising gradient value, so that the DC bus voltage rise amount will be reduced during the period of detecting grid voltage jump, so the embodiment of the present application can be compatible with high voltage at the same time
  • the control of the DC bus voltage is realized in the two scenarios of ride-through and power-off moment of operation.
  • the rising gradient value of the DC bus voltage reference value can represent a, for example, the value of a can include various values, such as a 1 and a 2 , the controller can reduce the rising gradient value of the DC bus voltage reference value, and the reduced
  • the current ascending gradient value is a V/ms, where a refers to the specific ascending gradient value, and V/ms is the unit of gradient.
  • a 1 satisfies the following relationship: b ⁇ a 1 ⁇ y/x;
  • a 1 and a 2 respectively satisfy the following relationship: b ⁇ a 1 ⁇ y/x;b ⁇ a 2 ⁇ y/x; wherein, b represents the reference for controlling the DC bus voltage The saturation speed of the value, the y represents the maximum allowable amplitude of the DC bus voltage, and the x represents the protection time required by the operating overvoltage.
  • the rising gradient value of the DC bus voltage reference value can represent a.
  • the value of a can include various values, such as a 1 and a 2.
  • the setting of the rising gradient aV/ms value can be based on the The bus voltage reference calculation module is implemented, the bus voltage reference calculation module includes the saturation speed of the controller, assuming that the saturation speed of the controller (such as a PI regulator) of the bus voltage reference calculation module is bV/ms, the protection time required by the operation overvoltage is xms, and the maximum allowable rise of the BUS voltage during this period is y V, then the value of a satisfies the following relationship: b ⁇ a ⁇ y/x. Therefore, the value of a can be determined through the above relationship.
  • the controller after reducing the rising gradient of the DC bus voltage reference value, the controller is further used to:
  • the output power of the inverter is controlled to increase.
  • the maximum value of the BUS voltage sampled in Tres is calculated, and ⁇ U is added, which is used as the BUS voltage reference value;
  • the voltage is sufficient to support the subsequent high-throughput power output; if the power grid is cut off, the BUS voltage increase in Tres is still within a reasonable range, for example, the BUS voltage does not reach the overvoltage point within a reasonable range; first raise the BUS voltage reference value to ensure functionality Output, and then make feature judgments to identify high wear.
  • the feature judgment refers to identifying the characteristics of the disconnected grid or the high wear-through feature.
  • the feature identification can be to obtain the characteristics of the grid voltage, grid frequency, and modulation ratio. In the embodiment of this application, the characteristics of the inverter that need to be obtained are not done limited.
  • the BUS voltage is passively raised, and the grid voltage suddenly rises, which will cause BUS backfeeding, that is, the energy of the grid is back poured into the DC bus, causing BUS Voltage rise:
  • the rise of the BUS voltage is mainly determined by the sudden increase of the grid voltage. If the sudden increase of the grid voltage is large, it will be shut down through the grid overvoltage protection.
  • the maximum value of the DC bus voltage sampling of the inverter is obtained, the first DC bus voltage reference value is obtained according to the maximum value of the DC bus voltage sampling, and the first DC bus voltage reference value is obtained according to the DC bus voltage sampling
  • the maximum value obtains the first DC bus voltage reference value, and the DC bus voltage reference value is greater than or equal to the sampling maximum value of the DC bus voltage;
  • the DC bus voltage raised by the backfeeding of the grid is sufficient to support the subsequent high-throughput power output;
  • the inverter is disconnected from the grid, according to the first DC bus voltage reference value and the preset first rising gradient Value obtains the second DC bus voltage reference value to limit the rising rate of the DC bus voltage, so that the rising amount of the DC bus voltage will be reduced during the detection period of the grid voltage jump, so the embodiment of the present application can be compatible with high voltage at the same time
  • the control of the DC bus voltage is realized in the two scenarios of ride-through and power
  • the controller provided in the embodiment of the present application may be a controller of an inverter, for example, the program code of the controller is burned into the control chip of the inverter.
  • each switching tube is an insulated gate bipolar transistor (insulated gate bipolar transistor, IGBT) for illustration. It should be understood that each switching tube can also be a metal Metal-oxide-semiconductor field-effect transistor (MOSFET) and other semiconductor devices.
  • IGBT insulated gate bipolar transistor
  • MOSFET metal Metal-oxide-semiconductor field-effect transistor
  • the controller is used for:
  • the maximum value of the BUS voltage sampled in Tres is calculated, and a reference value of the BUS voltage is obtained according to the maximum value.
  • Tres refers to the time period for detecting grid voltage jumps
  • ⁇ U refers to the difference between the actual BUS voltage reference value and the maximum value of the BUS voltage sampled within the Tres time.
  • V/ms (volt/millisecond) is the unit of the BUS voltage gradient
  • the rising gradient value of the DC bus voltage reference value can represent a 1 .
  • the rising rate of the BUS voltage is limited by setting the rising gradient of the BUS voltage reference value; because the control variable is the BUS voltage, the actual value of the BUS voltage is to track the BUS voltage reference value, and the rising gradient of the BUS voltage reference value is limited. The rate of rise of the actual value of the BUS voltage can be limited.
  • the rise rate of the BUS voltage there are two purposes for limiting the rise rate of the BUS voltage.
  • One is to suppress the rise of the AC port voltage (modulated by a fixed modulation ratio, the lower the BUS voltage, the lower the modulated AC port voltage);
  • the rise of the BUS voltage is limited before the feature detection and identification of the power grid outage, which buys time for the protection action.
  • the maximum value of the BUS voltage sampled in Tres is calculated, and ⁇ U is added as the reference value of the BUS voltage;
  • the raised BUS voltage is sufficient to support the subsequent high-throughput power output; in the event of a power outage, the BUS voltage increase in Tres is still within a reasonable range; first raise the BUS voltage reference value to ensure functional output, and then make a feature judgment. In order to identify the characteristics of high wear or power failure.
  • the actual value of the bus voltage follows the change of the bus voltage reference value, and the bus voltage reference value is quickly raised within Tres, and the rising gradient of the BUS voltage reference value in the controller is set to a 1 V/ms to limit the rise of the BUS voltage
  • the purpose of setting the rising gradient is to slow down the rate of positive feedback, reduce the influence of power grid voltage feedforward, ensure that the BUS voltage rises limited before the detection and identification of the characteristics of the power grid outage, and buy time for the protection action.
  • the positive feedback refers to the relationship between the BUS voltage and the AC port voltage. After the BUS voltage rises, the AC port voltage will rise, and after the AC port voltage rises, it will in turn lead to a further rise in the BUS voltage.
  • the rising gradient and the rising rate have similar meanings.
  • the rising gradient calibrates the quantization scale for the rising rate.
  • the unit of the rising gradient is V/ms. The larger the gradient value, the faster the rising rate.
  • the two-stage inverter may include: a DC/DC converter and a DC/AC converter.
  • a photovoltaic (photovoltaic, PV) component is used as a direct current source and connected to a DC/DC converter, the DC/DC converter is connected to a DC/AC converter, and the DC/AC converter is connected to a power grid through a switch.
  • PV photovoltaic
  • the PV module is composed of several PV panels in series, which are connected to the DC bus through the DC/DC converter, and then the energy is fed into the grid through the DC/AC converter.
  • the controller can include the following modules: grid voltage sampling module, bus voltage reference calculation module, grid voltage jump processing module, gradient processing module, bus voltage outer loop, current inner loop, sine pulse width modulation (sine pulse width modulation, SPWM) .
  • the grid voltage sampling module is used to sample the voltage of the grid to obtain the grid voltage, for example, the grid voltage is U grid , and the grid voltage is sent to the grid voltage jump processing module;
  • the bus voltage reference calculation module is used to calculate the DC bus voltage reference value.
  • the grid voltage jump processing module is used to judge whether the grid voltage jumps
  • the gradient processing module is used to set the rising gradient value of the BUS voltage reference value in the controller to a 1 V/ms, so as to limit the rising rate of the BUS voltage, for example, the output BUS voltage reference value is U busref ;
  • the bus voltage outer loop is used to control the DC bus voltage and output a current reference value, for example, the current reference value is I ref ;
  • the current inner loop is used to control the grid-connected current and output the modulated wave
  • SPWM is used to generate a driving signal according to the modulation wave output by the current inner loop, and input the driving signal into the DC/AC converter.
  • the inverter When the power grid is disconnected, the inverter cannot output the specified current, and the modulation wave output by the current inner loop continues to integrate and increase, resulting in a continuous increase in the voltage modulation ratio. In order to reduce the modulation ratio, the DC/AC converter will continue to increase the bus voltage. This further leads to an increase in the modulated inverter port voltage. There is a risk of stress in increasing the switch tube, which affects the safety of equipment operation.
  • the current inner loop refers to the control loop in the controller.
  • a specific application scenario provided by the embodiment of this application includes:
  • the BUS reference is first raised to ensure the functional output of the inverter, and then the characteristic judgment is made to identify high wear or power failure.
  • the power grid voltage jump is detected, it is not necessary to identify whether the high voltage ride-through occurs or the power grid is disconnected.
  • the actual bus voltage after the BUS back-feeding is directly used as the BUS voltage control reference. At this time, the bus voltage can meet the requirements of high voltage ride-through demand, and the voltage is not too high.
  • the inverter enters the follow-up grid-off feature recognition logic judgment, whether it is identified as a grid-off operation and meets the protection shutdown conditions; if it is satisfied, enter S05.
  • the grid outage is characterized by high grid voltage peaks, grid frequency fluctuations, and continuous overmodulation.
  • the protection shutdown condition of the inverter is that there is an alarm, and different alarm shutdowns will be reported according to the actual value of the BUS voltage and the variable characteristics inside the controller.
  • the rise rate of the BUS voltage is slow to reduce the stress risk of the IGBT module;
  • the rise gradient of the BUS voltage reference value in the controller is set to a 1 V/ms to limit the rise rate of the BUS voltage;
  • the gradient is added to slow down the positive feedback The rate is reduced to reduce the influence of the power grid feed-forward, to ensure that the BUS voltage rise is limited before the detection and identification of the power grid feature, to buy time for the protection action, and to reduce the stress risk of the IGBT module.
  • the embodiment of the present application does not specifically limit the implementation type of the switching transistor, which is specifically a controllable switching transistor, such as a metal oxide semiconductor field effect transistor, an insulated gate bipolar transistor, and the like.
  • At least one (item) means one or more, and “multiple” means two or more.
  • “And/or” is used to describe the association relationship of associated objects, indicating that there can be three types of relationships, for example, “A and/or B” can mean: only A exists, only B exists, and A and B exist at the same time , where A and B can be singular or plural.
  • the character “/” generally indicates that the contextual objects are an “or” relationship.
  • At least one of the following” or similar expressions refer to any combination of these items, including any combination of single or plural items.
  • At least one item (piece) of a, b or c can mean: a, b, c, "a and b", “a and c", “b and c", or "a and b and c ", where a, b, c can be single or multiple.
  • Each functional unit in each embodiment of the present application can be integrated into one processing unit, or each unit can be used as a single unit, or two or more units can be integrated into one unit, the above-mentioned integrated unit It can be implemented in the form of hardware or in the form of hardware plus software functional units.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Inverter Devices (AREA)

Abstract

一种直流母线电压的控制系统和控制方法。其中，一种直流母线电压的控制系统，包括：控制器和逆变器，逆变器的输出端和电网连接，所述逆变器的输入端通过直流母线与光伏组件连接；控制器用于获取电网电压；当电网电压发生跳变时，获取逆变器的直流母线电压采样最大值,直流母线电压采样最大值为检测电网电压跳变的时间段内在直流母线上的电压最大值；根据直流母线电压采样最大值获取第一直流母线电压参考值，其中，直流母线电压参考值大于或等于直流母线电压采样最大值；根据第一直流母线电压参考值和预设的第一上升梯度值获取第二直流母线电压参考值，以限制直流母线电压的上升速率。

Description

一种直流母线电压的控制系统和控制方法 技术领域
本申请实施例涉及电源技术领域，尤其涉及一种直流母线电压的控制系统和控制方法。
背景技术
逆变器可以和电网、负载设备分别相连接，例如逆变器可以是光伏并网逆变器。逆变器的输出端通过公共连接点直接与电网相连接，同时该输出端上可能连接其他负载设备，输出端与电网连接后，输出端的端口电压被电网钳位，端口电压幅值由电网电压大小决定。
当发生高电压穿越时，电网侧开关闭合，需要控制直流母线(BUS)电压。当进行断电网操作时，电网侧开关断开，也需要控制直流母线电压。
目前，针对直流母线电压的控制方案只能适用于高电压穿越场景，或者只能适用于断电网操作场景，即目前的针对直流母线电压的控制方案无法同时适用于上述两种场景。而在兼容高电压穿越和断电网操作瞬间这两种场景下如何对直流母线电压进行控制，是一个亟待解决的问题。
发明内容
本申请实施例提供了一种直流母线电压的控制系统和控制方法，用于实现在兼容高电压穿越和断电网操作瞬间这两种场景下对直流母线电压进行控制，将直流母线电压控制在合理范围内。
为解决上述技术问题，本申请实施例提供以下技术方案：
第一方面，本申请实施例提供一种直流母线电压的控制系统，包括：控制器和逆变器；
所述逆变器的输出端和电网连接，所述逆变器的输入端通过直流母线与光伏组件连接；
所述控制器，用于获取电网电压；
当所述电网电压发生跳变时，获取所述逆变器的直流母线电压采样最大值,所述直流母线电压采样最大值为检测电网电压跳变的时间段内在直流母线上的电压最大值；
根据所述直流母线电压采样最大值获取第一直流母线电压参考值，其中，所述第一直流母线电压参考值大于或等于所述直流母线电压采样最大值；
根据所述第一直流母线电压参考值和预设的第一上升梯度值获取第二直流母线电压参考值，以限制直流母线电压的上升速率。
在上述方案中，若逆变器发生高电压穿越(简称为高穿)，在检测电网电压跳变的时间段内电网反灌所抬升到的直流母线电压足以支撑后续的高穿功率输出；若逆变器发生断电网，根据所述第一直流母线电压参考值和预设的第一上升梯度值获取第二直流母线电压参考值，本申请实施例中通过预设的第一上升梯度值能够限制直流母线电压的上升速率，使得在检测电网电压跳变的时间段内直流母线电压的抬升量会被减少，因此本申请实施例可以同时兼容高电压穿越和断电网操作瞬间这两种场景，实现对直流母线电压的控制。
在一种可能的实现方式中，所述控制器，还用于：根据所述第二直流母线电压参考值和预设的第二上升梯度值获取第三直流母线电压参考值，其中，所述第二上升梯度值小于 所述第一上升梯度值。直流母线电压参考值的上升梯度从第一上升梯度值减少为第二上升梯度值，通过减少直流母线电压参考值的上升梯度，从而可以限制直流母线电压的上升速率，使得在检测电网电压跳变的时间段内直流母线电压的抬升量会被减少，因此本申请实施例可以同时兼容高电压穿越和断电网操作瞬间这两种场景，实现对直流母线电压的控制。
在一种可能的实现方式中，所述控制器，还用于：按照预设的电压幅度阈值调整所述直流母线电压采样最大值，以得到所述第一直流母线电压参考值。在上述方案中，本申请实施例中控制器在电网电压跳变时可以快速抬升直流母线电压采样最大值，以得到第一直流母线电压参考值，使得直流母线电压可以得到快速抬升。
在一种可能的实现方式中，所述控制器，还用于：通过如下方式得到所述第一直流母线电压参考值：U BUS-R＝U BUS-MAX+ΔU；其中，所述U BUS-R表示所述第一直流母线电压参考值，所述U BUS-MAX表示所述直流母线电压采样最大值，所述ΔU表示所述电压幅度阈值。在上述方案中，控制器在电网电压跳变时可以快速抬升直流母线电压采样最大值，以得到第一直流母线电压参考值，使得直流母线电压可以得到快速抬升。
在一种可能的实现方式中，所述控制器，还用于：根据所述逆变器进行高压穿越时需要使用的直流母线电压值确定所述电压幅度阈值。在上述方案中，电压幅度阈值可以用于调整直流母线电压采样最大值，以得到第一直流母线电压参考值，该电压幅度阈值具体通过逆变器进行高压穿越时需要使用的直流母线电压值，若直流母线电压采样最大值不能满足逆变器进行高压穿越时需要使用的直流母线电压值，则需要设置该电压幅度阈值较大，若直流母线电压采样最大值能够满足或者接近满足逆变器进行高压穿越时需要使用的直流母线电压值，则需要设置该电压幅度阈值较小或者为零。
在一种可能的实现方式中，所述电压幅度阈值为大于0或等于0的电压值。在上述方案中，电压幅度阈值可以表示为ΔU，关于ΔU的取值可以大于0或等于0。具体的，需要保证抬升后的直流BUS电压参考值能够满足高穿时需要使用的电压值；正常电网电压跳变后，会短时出现BUS电压反灌，即电网的能量反灌到直流母线上，造成BUS电压被动抬升。被动抬升后的BUS电压实际值在够高穿使用的情况下，对ΔU的取值进行整定，此时ΔU等于0，若直流母线电压采样最大值还不足以高穿时使用的电压值，则需要ΔU大于0，以使得直流母线电压参考值可以满足高穿时使用的电压值。对于ΔU的具体取值此处不做限定。
在一种可能的实现方式中，所述根据所述第一直流母线电压参考值和预设的第一上升梯度值获取第二直流母线电压参考值之后，所述控制器，还用于：当所述逆变器符合断电网特征时，对所述逆变器进行断电网操作。在上述方案中，控制器还可以检测逆变器是否符合断电网特征，在逆变器符合断电网特征时，控制器对逆变器进行断电网操作，因此适用于对逆变器的断电网场景。该断电网特征可以包括：电网电压峰值高，电网频率波动，并且发生持续过调制。
在一种可能的实现方式中，所述对所述逆变器进行断电网操作之后，所述控制器，还用于：当所述逆变器满足预设的保护关机条件时，控制所述逆变器进行关机。在上述方案中，保护关机条件是指逆变器是否需要保护关机的判断条件，控制器在对逆变器进行断电网操作之后，控制器可以判断该逆变器是否满足保护关机条件，在逆变器满足预设的保护关机条件时，对逆变器进行保护关机，此时逆变器在控制器的控制下关机，停止运行。
在一种可能的实现方式中，所述对所述逆变器进行断电网操作之后，所述控制器，还用于：当所述逆变器不满足所述保护关机条件时，触发重新获取电网电压的步骤。在上述方案中，保护关机条件是指逆变器是否需要保护关机的判断条件，控制器在对逆变器进行断电网操作之后，控制器可以判断该逆变器是否满足保护关机条件，在逆变器不满足保护关机条件时，重新执行判断电网电压是否跳变的步骤。
在一种可能的实现方式中，所述第一上升梯度值为a 1V/ms；其中，所述V/ms表示上升梯度值的单位为伏特每毫秒。在上述方案中，可以将a 1的取值减少，从而限制直流母线电压的上升速率，使得在检测电网电压跳变的时间段内直流母线电压的抬升量会被减少，因此本申请实施例可以同时兼容高电压穿越和断电网操作瞬间这两种场景，实现对直流母线电压的控制。
在一种可能的实现方式中，所述a 1满足如下关系：b<a 1<y/x；其中，所述b表示用于控制直流母线电压参考值的饱和速度，所述y表示所述直流母线电压的最大允许幅度，所述x表示操作过电压要求的保护时间。在上述方案中，直流母线电压参考值的上升梯度值可以表示a，例如a的取值可以包括多种，例如为a 1，关于上升梯度aV/ms值的整定，可以依据控制器中的母线电压参考计算模块实现，该母线电压参考计算模块包括控制器饱和速度，假设母线电压参考计算模块的控制器(例如PI调节器)的饱和速度为bV/ms，操作过电压要求的保护时间为xms，在这段时间内BUS电压的最大允许上升幅度为y V，那么a的取值满足如下关系：b<a<y/x，因此通过上述关系可以确定a的取值。
在一种可能的实现方式中，所述控制器，还用于：分别获取所述电网电压的峰值和所述电网电压的有效值；根据所述电网电压的峰值和所述电网电压的有效值判断所述电网电压是否发生跳变。在上述方案中，控制器中可以包括采样电路，通过该采样电路获取电网电压采样值，从而可以计算出电网电压的峰值和电网电压的有效值，最后根据计算得到的峰值和有效值判断电网电压是否跳变，实现了对电网电压是否跳变的判断。
在一种可能的实现方式中，所述根据所述第一直流母线电压参考值和预设的第一上升梯度值获取第二直流母线电压参考值之后，所述控制器，还用于：当所述逆变器符合高压穿越特征时，控制所述逆变器的输出功率增大。在上述方案中，检测到电网电压跳变时，计算在Tres内BUS电压采样的最大值，并加上ΔU，将其作为BUS电压参考值；若是发生高穿，Tres内电网反灌所抬升到的BUS电压足以支撑后续的高穿功率输出；若是发生断电网，Tres内BUS电压抬升量仍在合理范围内，例如合理范围是BUS电压没有达到过压点；先抬升BUS电压参考值，保证功能性输出，再做特征判断，识别高穿。其中，特征判断是指识别出断电网特征或者高穿特征，例如特征识别可以是获取电网电压、电网频率，调制比等特征，本申请实施例中对于需要获取的逆变器的特征不做限定。
第二方面，本申请实施例提供一种直流母线电压的控制方法，包括：获取电网电压，逆变器的输出端和电网连接，所述逆变器的输入端通过直流母线与光伏组件连接；当所述电网电压发生跳变时，获取所述逆变器的直流母线电压采样最大值,所述直流母线电压采样最大值为检测电网电压跳变的时间段内在直流母线上的电压最大值；根据所述直流母线电压采样最大值获取第一直流母线电压参考值，其中，所述直流母线电压参考值大于或等于所述直流母线电压采样最大值；根据所述第一直流母线电压参考值和预设的第一上升梯度 值获取第二直流母线电压参考值，以限制直流母线电压的上升速率。
在上述方案中，若逆变器发生高电压穿越(简称为高穿)，在检测电网电压跳变的时间段内电网反灌所抬升到的直流母线电压足以支撑后续的高穿功率输出；若逆变器发生断电网，根据所述第一直流母线电压参考值和预设的第一上升梯度值获取第二直流母线电压参考值，本申请实施例中通过预设的第一上升梯度值能够限制直流母线电压的上升速率，使得在检测电网电压跳变的时间段内直流母线电压的抬升量会被减少，因此本申请实施例可以同时兼容高电压穿越和断电网操作瞬间这两种场景，实现对直流母线电压的控制。
在一种可能的实现方式中，所述方法还包括：根据所述第二直流母线电压参考值和预设的第二上升梯度值获取第三直流母线电压参考值，其中，所述第二上升梯度值小于所述第一上升梯度值。直流母线电压参考值的上升梯度从第一上升梯度值减少为第二上升梯度值，通过减少直流母线电压参考值的上升梯度，从而可以限制直流母线电压的上升速率，使得在检测电网电压跳变的时间段内直流母线电压的抬升量会被减少，因此本申请实施例可以同时兼容高电压穿越和断电网操作瞬间这两种场景，实现对直流母线电压的控制。
在一种可能的实现方式中，所述根据所述直流母线电压采样最大值获取第一直流母线电压参考值，包括：按照预设的电压幅度阈值调整所述直流母线电压采样最大值，以得到所述第一直流母线电压参考值。在上述方案中，本申请实施例中控制器在电网电压跳变时可以快速抬升直流母线电压采样最大值，以得到第一直流母线电压参考值，使得直流母线电压可以得到快速抬升。
在一种可能的实现方式中，所述按照预设的电压幅度阈值调整所述直流母线电压采样最大值，以得到所述第一直流母线电压参考值，包括：通过如下方式得到所述第一直流母线电压参考值：U BUS-R＝U BUS-MAX+ΔU；其中，所述U BUS-R表示所述第一直流母线电压参考值，所述U BUS-MAX表示所述直流母线电压采样最大值，所述ΔU表示所述电压幅度阈值。在上述方案中，控制器在电网电压跳变时可以快速抬升直流母线电压采样最大值，以得到第一直流母线电压参考值，使得直流母线电压可以得到快速抬升。
在一种可能的实现方式中，所述方法还包括：根据所述逆变器进行高压穿越时需要使用的直流母线电压值确定所述电压幅度阈值。在上述方案中，电压幅度阈值可以用于调整直流母线电压采样最大值，以得到第一直流母线电压参考值，该电压幅度阈值具体通过逆变器进行高压穿越时需要使用的直流母线电压值，若直流母线电压采样最大值不能满足逆变器进行高压穿越时需要使用的直流母线电压值，则需要设置该电压幅度阈值较大，若直流母线电压采样最大值能够满足或者接近满足逆变器进行高压穿越时需要使用的直流母线电压值，则需要设置该电压幅度阈值较小或者为零。
在一种可能的实现方式中，所述电压幅度阈值为大于0或等于0的电压值。在上述方案中，电压幅度阈值可以表示为ΔU，关于ΔU的取值可以大于0或等于0。具体的，需要保证抬升后的直流BUS电压参考值能够满足高穿时需要使用的电压值；正常电网电压跳变后，会短时出现BUS电压反灌，即电网的能量反灌到直流母线上，造成BUS电压被动抬升。被动抬升后的BUS电压实际值在够高穿使用的情况下，对ΔU的取值进行整定，此时ΔU等于0，若直流母线电压采样最大值还不足以高穿时使用的电压值，则需要ΔU大于0，以使得直流母线电压参考值可以满足高穿时使用的电压值。对于ΔU的具体取值此处不做限定。
在一种可能的实现方式中，所述根据所述第一直流母线电压参考值和预设的第一上升梯度值获取第二直流母线电压参考值之后，所述方法还包括：当所述逆变器符合断电网特征时，对所述逆变器进行断电网操作。在上述方案中，控制器还可以检测逆变器是否符合断电网特征，在逆变器符合断电网特征时，控制器对逆变器进行断电网操作，因此适用于对逆变器的断电网场景。该断电网特征可以包括：电网电压峰值高，电网频率波动，并且发生持续过调制。
在一种可能的实现方式中，所述对所述逆变器进行断电网操作之后，所述方法还包括：当所述逆变器满足预设的保护关机条件时，控制所述逆变器进行关机。在上述方案中，保护关机条件是指逆变器是否需要保护关机的判断条件，控制器在对逆变器进行断电网操作之后，控制器可以判断该逆变器是否满足保护关机条件，在逆变器满足预设的保护关机条件时，对逆变器进行保护关机，此时逆变器在控制器的控制下关机，停止运行。
在一种可能的实现方式中，所述对所述逆变器进行断电网操作之后，所述方法还包括：当所述逆变器不满足所述保护关机条件时，触发重新获取电网电压的步骤。在上述方案中，保护关机条件是指逆变器是否需要保护关机的判断条件，控制器在对逆变器进行断电网操作之后，控制器可以判断该逆变器是否满足保护关机条件，在逆变器不满足保护关机条件时，重新执行判断电网电压是否跳变的步骤。
在一种可能的实现方式中，所述第一上升梯度值为a 1V/ms，其中，所述V/ms表示上升梯度值的单位为伏特每毫秒。在上述方案中，可以将a 1的取值减少，从而限制直流母线电压的上升速率，使得在检测电网电压跳变的时间段内直流母线电压的抬升量会被减少，因此本申请实施例可以同时兼容高电压穿越和断电网操作瞬间这两种场景，实现对直流母线电压的控制。
在一种可能的实现方式中，所述a 1满足如下关系：b<a 1<y/x，其中，所述b表示用于控制直流母线电压参考值的饱和速度，所述y表示所述直流母线电压的最大允许幅度，所述x表示操作过电压要求的保护时间。在上述方案中，直流母线电压参考值的上升梯度值可以表示a，例如a的取值可以包括多种，例如为a 1，关于上升梯度aV/ms值的整定，可以依据控制器中的母线电压参考计算模块实现，该母线电压参考计算模块包括控制器饱和速度，假设母线电压参考计算模块的控制器(例如PI调节器)的饱和速度为bV/ms，操作过电压要求的保护时间为xms，在这段时间内BUS电压的最大允许上升幅度为y V，那么a的取值满足如下关系：b<a<y/x，因此通过上述关系可以确定a的取值。
在一种可能的实现方式中，所述方法还包括：分别获取所述电网电压的峰值和所述电网电压的有效值；根据所述电网电压的峰值和所述电网电压的有效值判断所述电网电压是否发生跳变。在上述方案中，控制器中可以包括采样电路，通过该采样电路获取电网电压采样值，从而可以计算出电网电压的峰值和电网电压的有效值，最后根据计算得到的峰值和有效值判断电网电压是否跳变，实现了对电网电压是否跳变的判断。
在一种可能的实现方式中，所述根据所述第一直流母线电压参考值和预设的第一上升梯度值获取第二直流母线电压参考值之后，所述方法还包括：当所述逆变器符合高压穿越特征时，控制所述逆变器的输出功率增大。在上述方案中，检测到电网电压跳变时，计算在Tres内BUS电压采样的最大值，并加上ΔU，将其作为BUS电压参考值；若是发生高穿， Tres内电网反灌所抬升到的BUS电压足以支撑后续的高穿功率输出；若是发生断电网，Tres内BUS电压抬升量仍在合理范围内，例如合理范围是BUS电压没有达到过压点；先抬升BUS电压参考值，保证功能性输出，再做特征判断，识别高穿。其中，特征判断是指识别出断电网特征或者高穿特征，例如特征识别可以是获取电网电压、电网频率，调制比等特征，本申请实施例中对于需要获取的逆变器的特征不做限定。
从以上技术方案可以看出，本申请实施例具有以下优点：
在本申请实施例中，当电网电压跳变时，获取逆变器的直流母线电压采样最大值，根据直流母线电压采样最大值获取第一直流母线电压参考值，根据直流母线电压采样最大值获取第一直流母线电压参考值，该直流母线电压参考值大于或等于直流母线电压采样最大值；若逆变器发生高电压穿越(简称为高穿)，在检测电网电压跳变的时间段内电网反灌所抬升到的直流母线电压足以支撑后续的高穿功率输出；若逆变器发生断电网，根据所述第一直流母线电压参考值和预设的第一上升梯度值获取第二直流母线电压参考值，本申请实施例中通过预设的第一上升梯度值能够限制直流母线电压的上升速率，使得在检测电网电压跳变的时间段内直流母线电压的抬升量会被减少，因此本申请实施例可以同时兼容高电压穿越和断电网操作瞬间这两种场景，实现对直流母线电压的控制。
附图说明
图1为本申请实施例提供的一种直流母线电压的控制系统的组成结构示意图；
图2为本申请实施例提供的一种控制器执行的控制功能的实现方式示意图；
图3为本申请实施例提供的直流母线电压实际值与直流母线电压参考值之间的变化关系示意图；
图4为本申请实施例提供的一种两级式逆变器的组成结构示意图；
图5为本申请实施例提供的控制器的一种控制功能的应用场景示意图。
具体实施方式
本申请实施例提供了一种直流母线电压的控制系统和控制方法，用于实现在兼容高电压穿越和断电网操作瞬间这两种场景下对直流母线电压进行控制，将直流母线电压控制在合理范围内。
下面结合附图，对本申请的实施例进行描述。
本申请的说明书和权利要求书及上述附图中的术语“第一”、“第二”等是用于区别类似的对象，而不必用于描述特定的顺序或先后次序。应该理解这样使用的术语在适当情况下可以互换，这仅仅是描述本申请的实施例中对相同属性的对象在描述时所采用的区分方式。此外，术语“包括”和“具有”以及他们的任何变形，意图在于覆盖不排他的包含，以便包含一系列单元的过程、方法、系统、产品或设备不必限于那些单元，而是可包括没有清楚地列出的或对于这些过程、方法、产品或设备固有的其它单元。
如图1所示，本申请实施例提供一种直流母线电压的控制系统，所述控制系统100包括：控制器101和逆变器102，其中，
所述控制器101和所述逆变器102相连接；
所述控制器101，用于获取电网输入到逆变器102的电网电压，所述逆变器102的输出端与电网连接；当所述电网电压发生跳变时，获取所述逆变器102的直流母线电压采样最大值,所述直流母线电压采样最大值为检测电网电压跳变的时间段内在直流母线上的电压最大值；根据直流母线电压采样最大值确定直流母线电压参考值，其中，所述直流母线电压参考值大于或等于所述直流母线电压采样最大值；根据所述第一直流母线电压参考值和预设的第一上升梯度值获取第二直流母线电压参考值，以限制直流母线电压的上升速率。
其中，本申请实施例提供的控制器101可以是独立于逆变器102的控制装置，控制器101也可以是逆变器102中的控制单元，此处不做限定。
本申请实施例提供的逆变器102具体可以是光伏逆变器，例如可以是逆变器可以是光伏并网逆变器。逆变器102可以包括至少两个变换器，例如逆变器102可以包括直流/直流变换器(direct-current/direct-current converter，DC/DC)，和直流/交流变换器(direct-current/alternating-current converter，DC/AC)。例如本申请实施例中的DC/DC变换器可以包括但不限于非对称半桥反激变换器、非对称半桥正激变换器、LLC谐振变换器等。
通过前述实施例对直流母线电压的控制系统的说明可知，当电网电压跳变时，获取逆变器的直流母线电压采样最大值，根据直流母线电压采样最大值获取第一直流母线电压参考值，根据直流母线电压采样最大值获取第一直流母线电压参考值，该直流母线电压参考值大于或等于直流母线电压采样最大值；若逆变器发生高电压穿越(简称为高穿)，在检测电网电压跳变的时间段内电网反灌所抬升到的直流母线电压足以支撑后续的高穿功率输出；若逆变器发生断电网，根据所述第一直流母线电压参考值和预设的第一上升梯度值获取第二直流母线电压参考值，以限制直流母线电压的上升速率，使得在检测电网电压跳变的时间段内直流母线电压的抬升量会被减少，因此本申请实施例可以同时兼容高电压穿越和断电网操作瞬间这两种场景，实现对直流母线电压的控制。
接下来对本申请实施例中控制器执行的直流母线电压的控制功能进行说明，请参阅图2所示，本申请实施例提供的控制器，用于：
201、获取电网电压，逆变器的输出端和电网连接，逆变器的输入端通过直流母线与光伏组件连接。
其中，控制器具体可以是独立于逆变器的控制装置，控制器也可以是逆变器中的控制单元。例如控制器可以包括逆变器内部的采样电路，通过该采样电路对电网电压进行采样。或者控制器独立于逆变器，控制器通过与逆变器进行交互，以获取到电网电压。
本申请实施例中逆变器的输出端和电网连接，逆变器的输入端通过直流母线与光伏组件连接，光伏(photovoltaic，PV)组件作为直流源，在输出端与电网之间可以设置网侧开关，在逆变器正常并网工作时，该网侧开关可以断开，突然将交流侧电网断开连接。
202、当电网电压发生跳变时，获取逆变器的直流母线电压采样最大值,直流母线电压采样最大值为检测电网电压跳变的时间段内在直流母线上的电压最大值。
其中，控制器在获取到电网电压之后，控制器可以判断是否发生电网电压的跳变。在电网电压发生跳变时，控制器可以获取逆变器的直流母线电压采样最大值,该流母线电压采样最大值为检测电网电压跳变的时间段内在直流母线上的电压最大值，例如该检测电网电 压跳变的时间段表示为Tres，对于Tres的具体取值大小，以及Tres的起始时间点，此处不做限定。后续直流母线电压也可以称为BUS电压。
在本申请的一些实施例中，控制器，还用于：
分别获取电网电压的峰值和电网电压的有效值；
根据电网电压的峰值和电网电压的有效值判断电网电压是否发生跳变。
其中，控制器中可以包括采样电路，通过该采样电路获取电网电压采样值，从而可以计算出电网电压的峰值和电网电压的有效值，最后根据计算得到的峰值和有效值判断电网电压是否跳变，实现了对电网电压是否跳变的判断。
203、根据直流母线电压采样最大值获取第一直流母线电压参考值，其中，第一直流母线电压参考值大于或等于直流母线电压采样最大值。
其中，控制器在获取到直流母线电压采样最大值之后，根据该直流母线电压采样最大值获取第一直流母线电压参考值，只需要满足该第一直流母线电压参考值大于或等于直流母线电压采样最大值即可，对于第一直流母线电压参考值的具体取值，此处不做限定。
在本申请的一些实施例中，以直流母线电压采样最大值作为基础值，按照预设的电压幅度阈值调整该基础值，并将调整后得到的电压值作为第一直流母线电压参考值。第一直流母线电压参考值大于或等于直流母线电压采样最大值，对于第一直流母线电压参考值的具体取值此处不做限定。
在本申请的一些实施例中，根据直流母线电压采样最大值获取第一直流母线电压参考值，包括：
按照预设的电压幅度阈值调整直流母线电压采样最大值，以得到第一直流母线电压参考值。
其中，本申请实施例中控制器在电网电压跳变时可以快速抬升直流母线电压采样最大值，以得到第一直流母线电压参考值，使得直流母线电压可以得到快速抬升。
在本申请的一些实施例中，按照预设的电压幅度阈值调整直流母线电压采样最大值，以得到第一直流母线电压参考值，包括：
通过如下方式得到所述第一直流母线电压参考值：
U BUS-R＝U BUS-MAX+ΔU；
其中，U BUS-R表示第一直流母线电压参考值，U BUS-MAX表示直流母线电压采样最大值，ΔU表示电压幅度阈值。
需要说明的是，该电压幅度阈值可以表示为ΔU，ΔU的取值可以结合应用场景确定，对于该ΔU的取值方式，此处不做限定。
在本申请的一些实施例中，控制器还用于：
根据逆变器进行高压穿越时需要使用的直流母线电压值确定电压幅度阈值。
其中，电压幅度阈值可以用于调整直流母线电压采样最大值，以得到第一直流母线电压参考值，该电压幅度阈值具体通过逆变器进行高压穿越时需要使用的直流母线电压值确定，若直流母线电压采样最大值不能满足逆变器进行高压穿越时需要使用的直流母线电压值，则需要设置该电压幅度阈值较大，若直流母线电压采样最大值能够满足或者接近满足逆变器进行高压穿越时需要使用的直流母线电压值，则需要设置该电压幅度阈值较小或者 为零。
在本申请的一些实施例中，电压幅度阈值为大于0或等于0的电压值。
其中，电压幅度阈值可以表示为ΔU，关于ΔU的取值可以大于0或等于0。具体的，需要保证抬升后的直流BUS电压参考值能够满足高穿时需要使用的电压值；正常电网电压跳变后，会短时出现BUS电压反灌，即电网的能量反灌到直流母线上，造成BUS电压被动抬升。被动抬升后的BUS电压实际值在够高穿使用的情况下，对ΔU的取值进行整定，此时ΔU等于0，若直流母线电压采样最大值还不足以高穿时使用的电压值，则需要ΔU大于0，以使得直流母线电压参考值可以满足高穿时使用的电压值。对于ΔU的具体取值此处不做限定。
204、根据第一直流母线电压参考值和预设的第一上升梯度值获取第二直流母线电压参考值，以限制直流母线电压的上升速率。
其中，控制器在获取到当前时刻的第一直流母线电压参考值之后，还可以根据第一直流母线电压参考值和预设的上升梯度值获取当前时刻之后的其它时刻的直流母线电压参考值，例如，在每个时刻预设一个直流母线电压参考值的上升梯度值，该上升梯度值的取值是减小的，减少直流母线电压参考值的上升梯度值，可以限制直流母线电压的上升速率，使得直流母线电压的上升变缓。
在本申请的一些实施例中，控制器，还用于：
根据第二直流母线电压参考值和预设的第二上升梯度值获取第三直流母线电压参考值，其中，第二上升梯度值小于第一上升梯度值。
其中，控制器在获取到当前时刻的第一直流母线电压参考值之后，还可以根据第一直流母线电压参考值和预设的上升梯度值依次获取当前时刻之后的其它时刻的直流母线电压参考值，例如，在每个时刻预设一个直流母线电压参考值的上升梯度值，该上升梯度值的变化趋势为依次减小。减少直流母线电压参考值的上升梯度值，可以限制直流母线电压的上升速率，使得直流母线电压的上升变缓。
例如，在当前时刻获取第一直流母线电压参考值，根据第一直流母线电压参考值和预设的第一上升梯度值获取在下一时刻的第二直流母线电压参考值，在下一时刻获取第二直流母线电压参考值，根据第二直流母线电压参考值和预设的第二上升梯度值获取在下下一时刻的第三直流母线电压参考值，其中，第二上升梯度值小于第一上升梯度值，从而本申请实施例中通过设置BUS电压参考值的上升梯度来限制BUS电压的上升速率，因为控制量是BUS电压，BUS电压实际值一定是跟踪BUS电压参考值的，限制参考值的上升梯度，就可以限制BUS电压实际值的上升速率。
需要说明的是，直流母线电压参考值也可以称为BUS电压参考值，或者BUS电压参考值下限。
在本申请的一些实施例中，根据所述第一直流母线电压参考值和预设的第一上升梯度值获取第二直流母线电压参考值之后，控制器还用于：
当逆变器符合断电网特征时，对逆变器进行断电网操作。
其中，控制器还可以检测逆变器是否符合断电网特征，在逆变器符合断电网特征时，控制器对逆变器进行断电网操作，因此适用于对逆变器的断电网场景。该断电网特征可以 包括：电网电压峰值高，电网频率波动，并且发生持续过调制。
本申请实施例中，通过限制BUS电压上升速率，可以抑制交流端口电压的上升，即按固定调制比调制，BUS电压越低，调制出的交流端口电压越低；另外，可以保证在断电网特征检测识别前BUS电压上升有限，为保护动作争取时间。
在本申请的一些实施例中，对逆变器进行断电网操作之后，控制器还用于：
当逆变器满足预设的保护关机条件时，控制逆变器进行关机。
其中，保护关机条件是指逆变器是否需要保护关机的判断条件，控制器在对逆变器进行断电网操作之后，控制器可以判断该逆变器是否满足保护关机条件，在逆变器满足预设的保护关机条件时，对逆变器进行保护关机，此时逆变器在控制器的控制下关机，停止运行。
在本申请的一些实施例中，对逆变器进行断电网操作之后，控制器还用于：
当逆变器不满足保护关机条件时，触发重新获取电网电压的步骤201。
其中，保护关机条件是指逆变器是否需要保护关机的判断条件，控制器在对逆变器进行断电网操作之后，控制器可以判断该逆变器是否满足保护关机条件，在逆变器不满足保护关机条件时，重新执行步骤201至步骤204。
在本申请的一些实施例中，所述第一上升梯度值为a 1V/ms，其中，所述V/ms表示上升梯度值的单位为伏特每毫秒。
在本申请的一些实施例中，第一上升梯度值为a 1V/ms，所述第二上升梯度值为a 2V/ms；所述a 1和所述a 2满足如下关系：a 2<a 1；其中，所述V/ms表示上升梯度值的单位为伏特每毫秒。在上述方案中，第二上升梯度值小于所述第一上升梯度值，使得在检测电网电压跳变的时间段内直流母线电压的抬升量会被减少，因此本申请实施例可以同时兼容高电压穿越和断电网操作瞬间这两种场景，实现对直流母线电压的控制。
其中，直流母线电压参考值的上升梯度值可以表示a，例如a的取值可以包括多种，例如为a 1和a 2，控制器可以减少直流母线电压参考值的上升梯度值，减少后的当前上升梯度值为a V/ms，a代指具体的上升梯度值，V/ms是梯度的单位。
在本申请的一些实施例中，a 1满足如下关系：b<a 1<y/x；
在本申请的一些实施例中，a 1和a 2分别满足如下关系：b<a 1<y/x；b<a 2<y/x；其中，所述b表示用于控制直流母线电压参考值的饱和速度，所述y表示所述直流母线电压的最大允许幅度，所述x表示操作过电压要求的保护时间。
举例说明如下，直流母线电压参考值的上升梯度值可以表示a，例如a的取值可以包括多种，例如为a 1和a 2，关于上升梯度aV/ms值的整定，可以依据控制器中的母线电压参考计算模块实现，该母线电压参考计算模块包括控制器饱和速度，假设母线电压参考计算模块的控制器(例如PI调节器)的饱和速度为bV/ms，操作过电压要求的保护时间为xms，在这段时间内BUS电压的最大允许上升幅度为y V，那么a的取值满足如下关系：b<a<y/x。因此通过上述关系可以确定a的取值。
在本申请的一些实施例中，减少直流母线电压参考值的上升梯度之后，控制器还用于：
当逆变器符合高压穿越特征时，控制逆变器的输出功率增大。
其中，当检测到电网电压跳变时，计算在Tres内BUS电压采样的最大值，并加上ΔU， 将其作为BUS电压参考值；若是发生高穿，Tres内电网反灌所抬升到的BUS电压足以支撑后续的高穿功率输出；若是发生断电网，Tres内BUS电压抬升量仍在合理范围内，例如合理范围是BUS电压没有达到过压点；先抬升BUS电压参考值，保证功能性输出，再做特征判断，识别高穿。其中，特征判断是指识别出断电网特征或者高穿特征，例如特征识别可以是获取电网电压、电网频率，调制比等特征，本申请实施例中对于需要获取的逆变器的特征不做限定。
需要说明的是，在本申请实施例中，在Tres这段时间内，BUS电压是被动抬升，电网电压突然升高，会造成BUS反灌，即电网的能量反灌到直流母线上，造成BUS电压抬升；BUS电压的抬升量主要由电网电压突增的量来决定，如果电网电网突增很大，会通过电网过压保护关机。
通过前述实施例的举例说明可知，当电网电压跳变时，获取逆变器的直流母线电压采样最大值，根据直流母线电压采样最大值获取第一直流母线电压参考值，根据直流母线电压采样最大值获取第一直流母线电压参考值，该直流母线电压参考值大于或等于直流母线电压采样最大值；若逆变器发生高电压穿越(简称为高穿)，在检测电网电压跳变的时间段内电网反灌所抬升到的直流母线电压足以支撑后续的高穿功率输出；若逆变器发生断电网，根据所述第一直流母线电压参考值和预设的第一上升梯度值获取第二直流母线电压参考值，以限制直流母线电压的上升速率，使得在检测电网电压跳变的时间段内直流母线电压的抬升量会被减少，因此本申请实施例可以同时兼容高电压穿越和断电网操作瞬间这两种场景，实现对直流母线电压的控制。
为便于更好的理解和实施本申请实施例的上述方案，下面举例相应的应用场景来进行具体说明。
本申请实施例提供的控制器可以是逆变器的控制器，例如该控制器的程序代码烧录在逆变器的控制芯片里。接下来对本申请实施例中控制器对BUS电压的控制过程进行举例说明。
逆变器中包括多种开关管，本申请实施例以各个开关管为绝缘栅双极型晶体管(insulated gate bipolar transistor,IGBT)进行示例性说明，应当理解的是，各个开关管还可以是金属氧化物半导体场效应管(metal-oxide-semiconductor field-effect transistor,MOSFET)等其他半导体器件。
在逆变器发生断电网时，需要抑制母线电压抬升，保证在断网至保护阶段，直流母线电压始终在合理范围内；但是高电压穿越时，需要快速抬升直流母线电压，保证在规定时间内输出有功电流或者无功电流；目前没有能够兼容高电压穿越和断电网场景的直流母线电压的控制器，本申请实施例提供能够兼容上述两种场景的控制器，接下来进行详细说明。
本申请实施例中控制器，用于：
当检测到电网电压跳变时，计算在Tres内BUS电压采样的最大值，并根据该最大值获取BUS电压参考值。
设置控制器中的BUS电压参考值的上升梯度值为a 1V/ms，以限制BUS电压上升速率。
例如，在计算在Tres内BUS电压采样的最大值之后，并加上ΔU，将其作为BUS电压参考值。
其中，Tres指检测电网电压跳变的时间段，ΔU指实际作用的BUS电压参考值与BUS电压在Tres时间内采样最大值之间的差值。
其中，V/ms(伏/毫秒)是BUS电压梯度的单位，直流母线电压参考值的上升梯度值可以表示a 1。本申请实施例中，通过设置BUS电压参考值的上升梯度来限制BUS电压的上升速率；因为控制量是BUS电压，BUS电压实际值是跟踪BUS电压参考值，限制BUS电压参考值的上升梯度，就可以限制BUS电压实际值的上升速率。
本申请实施例中，限制BUS电压上升速率有两个目的，一是抑制交流端口电压的上升(按固定调制比调制，BUS电压越低，调制出的交流端口电压越低)；二是保证在断电网特征检测识别前BUS电压上升有限，为保护动作争取时间。
在本申请实施例中，当检测到电网电压跳变时，计算在Tres内BUS电压采样的最大值，并加上ΔU，将其作为BUS电压参考值；若是发生高穿，Tres内电网反灌所抬升到的BUS电压足以支撑后续的高穿功率输出；若是发生断电网，Tres内BUS电压抬升量仍在合理范围内；先抬升BUS电压参考值，保证功能性输出，再做特征判断，从而识别高穿特征或断电网特征。
如图3所示，母线电压实际值跟随母线电压参考值变化，在Tres内快速抬升母线电压参考值，设置控制器中的BUS电压参考值的上升梯度为a 1V/ms，限制BUS电压上升速率，设置上升梯度是为了减缓正反馈的速率，减小电网电压前馈的影响，保证在断电网特征检测识别前BUS电压上升有限，为保护动作争取时间。其中，正反馈是指BUS电压与交流端口电压之间的关系，BUS电压抬升后会导致交流端口电压的抬升，而交流端口电压抬升以后，又会反过来导致BUS电压进一步抬升。
需要说明的是，本申请实施例中上升梯度和上升速率含义类似，上升梯度给上升速率标定了量化尺度，上升梯度的单位V/ms，梯度值越大，上升速率越快。
接下来针对本申请实施例的应用场景为断电网场景进行说明，如图4所示，两级式逆变器可以包括：DC/DC变换器、DC/AC变换器。光伏(photovoltaic，PV)组件作为直流源连接DC/DC变换器，DC/DC变换器连接DC/AC变换器，DC/AC变换器通过开关和电网连接。在逆变器正常并网工作时，突然将交流侧电网断开连接。
PV组件由若干PV电池板串联组成，经过DC/DC变换器的连接到直流母线，然后经过DC/AC变换器将能量馈入电网。
控制器可以包括如下模块：电网电压采样模块、母线电压参考计算模块、电网电压跳变处理模块、梯度处理模块、母线电压外环、电流内环、正弦脉宽调制(sine pulse width modulation，SPWM)。
其中，电网电压采样模块，用于对电网的电压进行采样，以得到电网电压，例如电网电压为U grid，将该电网电压发送给电网电压跳变处理模块；
母线电压参考计算模块，用于计算直流母线电压参考值。
电网电压跳变处理模块，用于判断电网电压是否跳变；
梯度处理模块，用于设置控制器中的BUS电压参考值的上升梯度值为a 1V/ms，以限制BUS电压上升速率，例如输出BUS电压参考值为U busref；
母线电压外环，用于控制直流母线电压，输出电流参考值，例如电流参考值为I ref；
电流内环，用于控制并网电流，并输出调制波；
SPWM，用于根据电流内环输出的调制波产生驱动信号，并将该驱动信号输入DC/AC变换器。
当进行断电网操作时，逆变器无法输出指定电流，电流内环输出的调制波不断积分增大导致电压调制比持续增加，为降低调制比，DC/AC变换器会持续提高母线电压，进一步导致调制出的逆变端口电压增大。增大开关管存在应力风险，影响设备运行安全。其中，电流内环指的是控制器中的控制环路。
当检测到电网电压跳变时，计算在Tres内BUS电压采样的最大值，并加上ΔU，将其作为BUS电压参考值，快速抬升BUS电压参考值；设置控制器中的BUS电压参考值的上升梯度为a 1V/ms，从而会限制BUS电压上升速率，保证在断电网特征检测识别前BUS电压上升有限，为电网故障识别和保护动作争取时间。
如图5所示，本申请实施例提供的一个具体应用场景，包括：
S01：逆变器判断当前电网电压是否产生跳变，若超过进入S02。
S02：检测在Tres内BUS电压采样的最大值，并加上ΔU，作为当前BUS电压的参考值，快速抬升BUS电压参考。
其中，先抬升BUS参考，保证逆变器的功能性输出，再做特征判断，识别高穿或断电网。当检测到电网电压跳变时，先不去识别到底发生高穿还是断电网，直接根据BUS反灌抬升后的实际母线电压去作为BUS电压控制基准，这时母线电压可以满足高电压穿越的需求，又不至于电压太高。
S03：设置BUS电压参考值的上升梯度值为a 1V/ms，以限制BUS电压上升速率。
S04：逆变器进入后续断电网特征识别逻辑判断，是否识别为断电网操作并且满足保护关机条件；若满足进入S05。
其中，断电网特征是电网电压峰值高，电网频率波动，并且发生持续过调制。逆变器保护关机条件是有告警产生，根据BUS电压实际值和控制器内部的变量特征会上报不同的告警关机。
S05：逆变器保护关机，停止运行。
本申请实施例中，可以兼容高电压穿越和断电网场景；当检测到电网电压跳变时，计算在Tres内BUS电压采样的最大值，并加上ΔU，将其作为BUS电压参考值；若是发生高穿，Tres内电网反灌所抬升到的BUS电压足以支撑后续的高穿功率输出；若是发生断电网，Tres内BUS电压抬升量仍在合理范围内；因此可以兼容两种场景。
本申请实施例中，BUS电压上升速率缓慢，降低IGBT模块应力风险；设置控制器中的BUS电压参考值的上升梯度为a 1V/ms，限制BUS电压上升速率；加梯度是为了减缓正反馈的速率，减小电网电网前馈的影响，保证在断电网特征检测识别前BUS电压上升有限，为保护动作争取时间，同时也降低了IGBT模块应力风险。
需要说明的是，对于前述的各实施例，为了简单描述，故将其都表述为一系列的动作组合，但是本领域技术人员应该知悉，本申请并不受所描述的动作顺序的限制，因为依据本申请，某些步骤可以采用其他顺序或者同时进行。其次，本领域技术人员也应该知悉，说明书中所描述的实施例均属于优选实施例，所涉及的动作和模块并不一定是 本申请所必须的。
本申请实施例不具体限定开关管的实现类型，具体为可控开关管，例如金属氧化物半导体场效应晶体管，绝缘栅双极型晶体管等。
需要说明的是，本申请的说明书和权利要求书及上述附图中的术语“第一”、“第二”仅用于描述目的，而不能理解为指示或暗示相对重要性。上述术语“第一”、“第二”等是用于区别类似的对象，而不必用于描述特定的顺序或先后次序。应该理解这样使用的术语在适当情况下可以互换，这仅仅是描述本申请的实施例中对相同属性的对象在描述时所采用的区分方式。此外，术语“包括”和“具有”以及他们的任何变形，意图在于覆盖不排他的包含，以便包含一系列单元的过程、方法、系统、产品或设备不必限于那些单元，而是可包括没有清楚地列出的或对于这些过程、方法、产品或设备固有的其它单元。
在本申请中，“至少一个(项)”是指一个或者多个，“多个”是指两个或两个以上。“和/或”，用于描述关联对象的关联关系，表示可以存在三种关系，例如，“A和/或B”可以表示：只存在A，只存在B以及同时存在A和B三种情况，其中A，B可以是单数或者复数。字符“/”一般表示前后关联对象是一种“或”的关系。“以下至少一项(个)”或其类似表达，是指这些项中的任意组合，包括单项(个)或复数项(个)的任意组合。例如，a，b或c中的至少一项(个)，可以表示：a，b，c，“a和b”，“a和c”，“b和c”，或“a和b和c”，其中a，b，c可以是单个，也可以是多个。
在本申请各实施例中的各功能单元可以全部集成在一个处理单元中，也可以是各单元分别单独作为一个单元，也可以两个或两个以上单元集成在一个单元中，上述集成的单元既可以采用硬件的形式实现，也可以采用硬件加软件功能单元的形式实现。
以上所述，仅是本申请的较佳实施例而已，并非对本申请作任何形式上的限制。虽然本申请已以较佳实施例揭露如上，然而并非用以限定本申请。任何熟悉本领域的技术人员，在不脱离本申请技术方案范围情况下，都可利用上述揭示的方法和技术内容对本申请技术方案做出许多可能的变动和修饰，或修改为等同变化的等效实施例。因此，凡是未脱离本申请技术方案的内容，依据本申请的技术实质对以上实施例所做的任何简单修改、等同变化及修饰，均仍属于本申请技术方案保护的范围内。

Claims (20)

  1. 一种直流母线电压的控制系统，其特征在于，所述控制系统包括：控制器和逆变器，其中，
    所述逆变器的输出端和电网连接，所述逆变器的输入端通过直流母线与光伏组件连接；
    所述控制器，用于获取电网电压；
    当所述电网电压发生跳变时，获取所述逆变器的直流母线电压采样最大值,所述直流母线电压采样最大值为检测电网电压跳变的时间段内在直流母线上的电压最大值；
    根据所述直流母线电压采样最大值获取第一直流母线电压参考值，其中，所述第一直流母线电压参考值大于或等于所述直流母线电压采样最大值；
    根据所述第一直流母线电压参考值和预设的第一上升梯度值获取第二直流母线电压参考值，以限制直流母线电压的上升速率。
  2. 根据权利要求1所述的控制系统，其特征在于，所述控制器，还用于：
    根据所述第二直流母线电压参考值和预设的第二上升梯度值获取第三直流母线电压参考值，其中，所述第二上升梯度值小于所述第一上升梯度值。
  3. 根据权利要求1或2所述的控制系统，其特征在于，所述控制器，还用于：
    按照预设的电压幅度阈值调整所述直流母线电压采样最大值，以得到所述第一直流母线电压参考值。
  4. 根据权利要求3所述的控制系统，其特征在于，所述控制器，还用于：
    通过如下方式得到所述第一直流母线电压参考值：
    U BUS-R＝U BUS-MAX+ΔU；
    其中，所述U BUS-R表示所述第一直流母线电压参考值，所述U BUS-MAX表示所述直流母线电压采样最大值，所述ΔU表示所述电压幅度阈值。
  5. 根据权利要求3或4所述的控制系统，其特征在于，所述控制器，还用于：
    根据所述逆变器进行高压穿越时需要使用的直流母线电压值确定所述电压幅度阈值。
  6. 根据权利要求3至5中任一项所述的控制系统，其特征在于，所述电压幅度阈值为大于0或等于0的电压值。
  7. 根据权利要求1至6中任一项所述的控制系统，其特征在于，所述根据所述第一直流母线电压参考值和预设的第一上升梯度值获取第二直流母线电压参考值之后，所述控制器，还用于：
    当所述逆变器符合断电网特征时，对所述逆变器进行断电网操作。
  8. 根据权利要求7所述的控制系统，其特征在于，所述对所述逆变器进行断电网操作之后，所述控制器，还用于：
    当所述逆变器满足预设的保护关机条件时，控制所述逆变器进行关机。
  9. 根据权利要求7所述的控制系统，其特征在于，所述对所述逆变器进行断电网操作之后，所述控制器，还用于：
    当所述逆变器不满足所述保护关机条件时，触发重新获取电网电压的步骤。
  10. 根据权利要求1至9中任一项所述的控制系统，其特征在于，所述第一上升梯度值为a 1V/ms；
    其中，所述V/ms表示上升梯度值的单位为伏特每毫秒。
  11. 根据权利要求10所述的控制系统，其特征在于，所述a 1满足如下关系：
    b<a 1<y/x；
    其中，所述b表示用于控制直流母线电压参考值的饱和速度，所述y表示所述直流母线电压的最大允许幅度，所述x表示操作过电压要求的保护时间。
  12. 根据权利要求1至11中任一项所述的控制系统，其特征在于，所述控制器，还用于：
    分别获取所述电网电压的峰值和所述电网电压的有效值；
    根据所述电网电压的峰值和所述电网电压的有效值判断所述电网电压是否发生跳变。
  13. 根据权利要求1至12中任一项所述的控制系统，其特征在于，所述根据所述第一直流母线电压参考值和预设的第一上升梯度值获取第二直流母线电压参考值之后，所述控制器，还用于：
    当所述逆变器符合高压穿越特征时，控制所述逆变器的输出功率增大。
  14. 一种直流母线电压的控制方法，其特征在于，所述方法用于实现对逆变器的控制，逆变器的输出端和电网连接，所述逆变器的输入端通过直流母线与光伏组件连接，所述方法包括：
    获取电网电压；
    当所述电网电压发生跳变时，获取所述逆变器的直流母线电压采样最大值,所述直流母线电压采样最大值为检测电网电压跳变的时间段内在直流母线上的电压最大值；
    根据所述直流母线电压采样最大值获取第一直流母线电压参考值，其中，所述第一直流母线电压参考值大于或等于所述直流母线电压采样最大值；
    根据所述第一直流母线电压参考值和预设的第一上升梯度值获取第二直流母线电压参考值，以限制直流母线电压的上升速率。
  15. 根据权利要求14所述的方法，其特征在于，所述方法还包括：
    根据所述第二直流母线电压参考值和预设的第二上升梯度值获取第三直流母线电压参考值，其中，所述第二上升梯度值小于所述第一上升梯度值。
  16. 根据权利要求14或15所述的方法，其特征在于，所述根据所述直流母线电压采样最大值获取第一直流母线电压参考值，包括：
    按照预设的电压幅度阈值调整所述直流母线电压采样最大值，以得到所述第一直流母线电压参考值。
  17. 根据权利要求16所述的方法，其特征在于，所述按照预设的电压幅度阈值调整所述直流母线电压采样最大值，以得到所述第一直流母线电压参考值，包括：
    通过如下方式得到所述第一直流母线电压参考值：
    U BUS-R＝U BUS-MAX+ΔU；
    其中，所述U BUS-R表示所述第一直流母线电压参考值，所述U BUS-MAX表示所述直流母线电压采样最大值，所述ΔU表示所述电压幅度阈值。
  18. 根据权利要求16至17中任一项所述的方法，其特征在于，所述电压幅度阈值为大于0或等于0的电压值。
  19. 根据权利要求14至17中任一项所述的方法，其特征在于，所述第一上升梯度值为a 1V/ms；
    其中，所述V/ms表示上升梯度值的单位为伏特每毫秒。
  20. 根据权利要求19所述的方法，其特征在于，所述a 1满足关系：
    b<a 1<y/x；
    其中，所述b表示用于控制直流母线电压参考值的饱和速度，所述y表示所述直流母线电压的最大允许幅度，所述x表示操作过电压要求的保护时间。
PCT/CN2021/103500 2021-06-30 2021-06-30 一种直流母线电压的控制系统和控制方法 WO2023272579A1 (zh)

Priority Applications (4)

Application Number Priority Date Filing Date Title
EP21947533.2A EP4344010A1 (en) 2021-06-30 2021-06-30 Control system for direct current bus voltage, and control method
PCT/CN2021/103500 WO2023272579A1 (zh) 2021-06-30 2021-06-30 一种直流母线电压的控制系统和控制方法
CN202180099004.8A CN117461233A (zh) 2021-06-30 2021-06-30 一种直流母线电压的控制系统和控制方法
US18/398,776 US20240128745A1 (en) 2021-06-30 2023-12-28 System and method for controlling direct current bus voltage

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/CN2021/103500 WO2023272579A1 (zh) 2021-06-30 2021-06-30 一种直流母线电压的控制系统和控制方法

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US18/398,776 Continuation US20240128745A1 (en) 2021-06-30 2023-12-28 System and method for controlling direct current bus voltage

Publications (1)

Publication Number Publication Date
WO2023272579A1 true WO2023272579A1 (zh) 2023-01-05

Family

ID=84692393

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2021/103500 WO2023272579A1 (zh) 2021-06-30 2021-06-30 一种直流母线电压的控制系统和控制方法

Country Status (4)

Country Link
US (1) US20240128745A1 (zh)
EP (1) EP4344010A1 (zh)
CN (1) CN117461233A (zh)
WO (1) WO2023272579A1 (zh)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116526429A (zh) * 2023-07-04 2023-08-01 深圳市首航新能源股份有限公司 逆变器与储能系统
CN116545040A (zh) * 2023-07-07 2023-08-04 锦浪科技股份有限公司 低电压穿越中有功电流控制方法、装置、系统及存储介质

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2012023916A (ja) * 2010-07-16 2012-02-02 Mitsubishi Electric Corp 電力変換装置
CN107102224A (zh) * 2017-03-31 2017-08-29 许继电气股份有限公司 一种输电系统空载加压试验方法、其性能检测方法及装置
CN110571781A (zh) * 2018-06-05 2019-12-13 台达电子工业股份有限公司 直流母线电压控制方法与系统
CN110994628A (zh) * 2019-11-14 2020-04-10 特变电工西安电气科技有限公司 一种两级式光伏逆变器的高电压穿越控制方法

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2012023916A (ja) * 2010-07-16 2012-02-02 Mitsubishi Electric Corp 電力変換装置
CN107102224A (zh) * 2017-03-31 2017-08-29 许继电气股份有限公司 一种输电系统空载加压试验方法、其性能检测方法及装置
CN110571781A (zh) * 2018-06-05 2019-12-13 台达电子工业股份有限公司 直流母线电压控制方法与系统
CN110994628A (zh) * 2019-11-14 2020-04-10 特变电工西安电气科技有限公司 一种两级式光伏逆变器的高电压穿越控制方法

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116526429A (zh) * 2023-07-04 2023-08-01 深圳市首航新能源股份有限公司 逆变器与储能系统
CN116545040A (zh) * 2023-07-07 2023-08-04 锦浪科技股份有限公司 低电压穿越中有功电流控制方法、装置、系统及存储介质
CN116545040B (zh) * 2023-07-07 2023-09-26 锦浪科技股份有限公司 低电压穿越中有功电流控制方法、装置、系统及存储介质

Also Published As

Publication number Publication date
CN117461233A (zh) 2024-01-26
EP4344010A1 (en) 2024-03-27
US20240128745A1 (en) 2024-04-18

Similar Documents

Publication Publication Date Title
US20240072534A1 (en) Start method for photovoltaic rapid shutdown system, application apparatus and system
WO2023272579A1 (zh) 一种直流母线电压的控制系统和控制方法
US10014686B2 (en) Commutation control method and commutation control apparatus
US8559201B2 (en) Grid-connected inverter
US11075540B2 (en) Uninterruptible power supply device
US20230291201A1 (en) Control method for photovoltaic rapid switching-off system, and application apparatus and system therefor
US11316443B2 (en) Control of active neutral-point clamped three-level converter
US20110304941A1 (en) Switching device
US8792215B2 (en) Switch unit and power generation system thereof
CN108847835B (zh) 一种功率器件驱动保护电路及其控制方法
US10312795B2 (en) Inverter device capable of suppressing overcurrent without increasing a load and operation control method
US20190044377A1 (en) Uninterruptible power supply
CN112978537B (zh) 电梯抱闸故障的保护方法
JP2018057213A (ja) 電力変換システム、電力変換装置
US10797515B2 (en) Method for controlling an uninterruptible power supply and system for an uninterruptible power supply
AU2016269508B2 (en) DC/AC converter comprising control means for inrush current protection
US11973351B2 (en) Power converter
US10886835B2 (en) Solid state regulator and circuit breaker for high-power DC bus distributions
US20230261654A1 (en) Drive device to drive semiconductor element, semiconductor device, and power conversion device
US20240079882A1 (en) Photovoltaic Power Generation System Control Method, Photovoltaic Power Generation System, and Switching Apparatus
US20230223866A1 (en) Method of clamping output current of three-phase power converter
EP4207582A1 (en) Power conversion apparatus and control method for power conversion apparatus
CN113726209B (zh) 一种风电变流器用卸荷电路及其控制方法
CN211630103U (zh) 带耦合电感升压器的可调速驱动器
CN112911748B (zh) 一种电磁加热设备的控制方法及装置

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 21947533

Country of ref document: EP

Kind code of ref document: A1

WWE Wipo information: entry into national phase

Ref document number: 202180099004.8

Country of ref document: CN

WWE Wipo information: entry into national phase

Ref document number: 2021947533

Country of ref document: EP

ENP Entry into the national phase

Ref document number: 2021947533

Country of ref document: EP

Effective date: 20231221

NENP Non-entry into the national phase

Ref country code: DE