WO2024067105A1 - 功率控制方法、功率变换器及供电*** - Google Patents

功率控制方法、功率变换器及供电*** Download PDF

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Publication number
WO2024067105A1
WO2024067105A1 PCT/CN2023/118636 CN2023118636W WO2024067105A1 WO 2024067105 A1 WO2024067105 A1 WO 2024067105A1 CN 2023118636 W CN2023118636 W CN 2023118636W WO 2024067105 A1 WO2024067105 A1 WO 2024067105A1
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Prior art keywords
power
electrical quantity
droop
equal
reference value
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PCT/CN2023/118636
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English (en)
French (fr)
Inventor
陈剑波
辛凯
李俊杰
董明轩
Original Assignee
华为数字能源技术有限公司
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Publication of WO2024067105A1 publication Critical patent/WO2024067105A1/zh

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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
    • H02J3/46—Controlling of the sharing of output between the generators, converters, or transformers
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0003—Details of control, feedback or regulation circuits
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy
    • Y02E10/56—Power conversion systems, e.g. maximum power point trackers

Definitions

  • the present application relates to the field of electronic power technology, and in particular to a power control method, a power converter and a power supply system.
  • energy storage converters are usually used as voltage sources, and new energy converters such as photovoltaic converters and wind power converters are used as current sources to jointly supply power to the loads in the microgrid.
  • new energy converters such as photovoltaic converters and wind power converters are used as current sources to jointly supply power to the loads in the microgrid.
  • the capacity of the current source is much higher than the capacity of the voltage source, such as the installed capacity ratio of photovoltaic converters to energy storage converters is 2 or 3, or even higher, thus forming a local high photovoltaic-to-storage ratio scenario.
  • the inventor of this application found in the process of research and experiment that in the prior art, by locally increasing the installed capacity of the energy storage converter, the high light-to-storage ratio scenario can be avoided, so that when the regional circuit breaker is disconnected, the energy storage converter has the ability to stabilize the voltage and frequency and will not be overloaded.
  • this technical solution has large constraints on the configuration of the installed capacity of each area of the microgrid, and it is impossible to flexibly configure the installed capacity of the power supply unit and the energy storage converter according to local conditions.
  • the total installed capacity after configuration is large and the cost is high.
  • the present application provides a power control method, a power converter and a power supply system, which can realize rapid adjustment of the output power of the power converter in a region under a high light-to-energy ratio scenario, thereby improving the reliability and safety of the power converter.
  • the present application provides a power converter, the power converter comprising a controller and a power conversion circuit, the controller being connected to the power conversion circuit.
  • the controller can be used to obtain a target power reference value of the power conversion circuit based on an output electrical quantity of the power conversion circuit and a plurality of droop hysteresis loops; the controller can also be used to control the output power value of the power conversion circuit to be equal to the target power reference value.
  • a controller is added to limit the output power of the power conversion circuit.
  • the input of the controller is the output electrical quantity of the power conversion circuit, and the output is the power limit.
  • the multi-segment droop hysteresis loop surface is used to represent the corresponding relationship between the output electrical quantity and the power limit, that is, the controller can obtain the power limit according to the output electrical quantity and the multi-segment droop hysteresis loop surface.
  • the power limit is compared with the original power reference value of the power conversion circuit to obtain a target power reference value, and the output power value of the power conversion circuit is controlled to be equal to the target power reference value, so that the output power of the power converter in the area can be quickly adjusted in a high light-to-storage ratio scenario, thereby improving the reliability and safety of the power converter.
  • the controller is used to obtain a power limit value corresponding to the output electrical quantity based on the output electrical quantity and a multi-segment droop hysteresis surface; when the original power reference value is less than 0, the target power reference value is equal to 0; when the original power reference value is greater than or equal to 0 and less than or equal to the power limit, the target power reference value is equal to the original power reference value; when the original power reference value is greater than the power limit, the target power reference value is equal to the power limit.
  • a multi-segment droop hysteresis surface is used to represent the corresponding relationship between the output electrical quantity and the power limit, that is, the controller can obtain the power limit according to the output electrical quantity and the multi-segment droop hysteresis surface.
  • the controller obtains the target power reference value by comparing the power limit with the original power reference value of the power conversion circuit, which can be understood as limiting the original power reference value by the power limit to obtain the target power reference value. For example, the lowest value of the limit is 0, and the highest value is the power limit, that is, the target power reference value is greater than or equal to 0 and less than or equal to the power limit.
  • the target power reference value obtained by limiting is equal to 0; when the original power reference value is greater than or equal to 0 and less than or equal to the power limit, the target power reference value obtained by limiting is equal to the original power reference value; when the original power reference value is greater than the power limit, the target power reference value obtained by limiting is equal to the power limit.
  • the output power value of the power conversion circuit is controlled to be equal to the target power reference value, thereby achieving rapid adjustment of the output power of the power converter in the area under high light-to-energy ratio scenarios, thereby improving the reliability and safety of the power converter.
  • the controller is used to output the electrical quantity when it is greater than or equal to the first electrical quantity threshold and less than the second electrical quantity threshold.
  • the power limit corresponding to the output electrical quantity is the value corresponding to the hysteresis segment curve in the multi-segment droop hysteresis surface.
  • the power limit when the output electrical quantity is greater than or equal to the first electrical quantity threshold, the power limit can be obtained according to the multi-segment droop hysteresis surface.
  • the multi-segment droop hysteresis surface can include a hysteresis segment curve and N droop curves.
  • the power limit when the output electrical quantity is greater than or equal to the first electrical quantity threshold and less than the second electrical quantity threshold, the power limit can be the value corresponding to the hysteresis segment curve.
  • the hysteresis segment curve can avoid entering the power limit into the droop curve multiple times in a short period of time, provide sufficient time for the upper power scheduling, avoid large-scale up and down fluctuations in the output power, thereby avoiding repeated continuous oscillations of the output power of the power converter and improving system stability.
  • the controller is used to obtain the power limit value corresponding to the output electrical quantity as the value corresponding to the first droop curve in a multi-segment droop hysteresis surface when the output electrical quantity is greater than or equal to the second electrical quantity threshold and less than the third electrical quantity threshold; when the output electrical quantity is greater than or equal to the third electrical quantity threshold and less than the fourth electrical quantity threshold, obtain the power limit value corresponding to the output electrical quantity as the value corresponding to the second droop curve in the multi-segment droop hysteresis surface; when the output electrical quantity is greater than or equal to the N+1th electrical quantity threshold and less than the N+2th electrical quantity threshold, obtain the power limit value corresponding to the output electrical quantity as the value corresponding to the Nth droop curve in the multi-segment droop hysteresis surface, where N is a positive integer greater than or equal to 1.
  • the power limit value when the output electrical quantity is greater than the second electrical quantity threshold, the power limit value enters the N-segment droop curve, and the power limit value can correspond to the value corresponding to a certain droop curve in the N-segment droop curve according to the size of the electrical quantity threshold.
  • Different power limits are adopted in different reference voltage intervals, and the power limit value is compared with the original power reference value of the power conversion circuit to obtain a target power reference value, and the output power value of the power conversion circuit is controlled to be equal to the target power reference value, so that the output power of the power converter in the area can be quickly adjusted in a high light-to-storage ratio scenario, thereby improving the reliability and safety of the power converter.
  • the power limit corresponding to the output electrical quantity is the value corresponding to N droop curves in a multi-segment droop hysteresis surface
  • the power limit corresponding to the first moment is less than or equal to the power limit corresponding to the second moment, and the first moment is later than the second moment.
  • the power limit values on adjacent time sequences only decrease and do not increase, which can avoid large-scale up and down fluctuations in the output power of the power converter, thereby avoiding repeated and continuous oscillations in the output power of the power converter and improving system stability.
  • the controller is used to increase the power limit to a value corresponding to a hysteresis curve in a multi-segment droop hysteresis surface according to a preset time when the time when the output electrical quantity is less than the second electrical quantity threshold reaches a first threshold.
  • the power limit when it is detected that the output electrical quantity of the power converter tends to be normal, the power limit is restored. That is, when the time when the output electrical quantity is less than the second electrical quantity threshold reaches the first threshold, it can be said that the output electrical quantity of the power converter is in a normal state, and the power limit can be restored according to a predefined certain gradient, and the power limit is restored to the value corresponding to the hysteresis segment curve.
  • the predefined certain gradient can be understood as a preset period of time, and the power limit is increased to the value corresponding to the hysteresis segment curve in the multi-segment droop hysteresis surface within the preset time.
  • the controller is used to increase the preset time when the number of times the output electrical quantity is greater than or equal to the second electrical quantity threshold exceeds the second threshold.
  • the speed of power limit recovery can be slowed down accordingly according to the number of times the N-segment droop curve is entered, so as to provide sufficient adjustment time for upper-layer power scheduling.
  • the target power reference value is a target active power reference value or a target reactive power reference value.
  • the present application provides a power control method for a power converter, the method being applicable to a controller in a power converter, the power converter further comprising a power conversion circuit, the controller being connected to the power conversion circuit.
  • the method may include: obtaining a target power reference value of the power conversion circuit based on an output electrical quantity of the power conversion circuit and a multi-segment droop hysteresis loop surface; and controlling the output power value of the power conversion circuit to be equal to the target power reference value.
  • a controller is added to limit the output power of the power conversion circuit.
  • the input of the controller is the output electrical quantity of the power conversion circuit, and the output is the power limit.
  • the multi-segment droop hysteresis loop surface is used to represent the corresponding relationship between the output electrical quantity and the power limit, that is, the controller can obtain the power limit according to the output electrical quantity and the multi-segment droop hysteresis loop surface.
  • the power limit is compared with the original power reference value of the power conversion circuit to obtain a target power reference value, and the output power value of the power conversion circuit is controlled to be equal to the target power reference value, so that the output power of the power converter in the area can be quickly adjusted in a high light-to-storage ratio scenario, thereby improving the reliability and safety of the power converter.
  • obtaining a target power reference value of a power conversion circuit based on an output electrical quantity of a power conversion circuit and a multi-segment droop hysteresis surface includes: obtaining a power limit value corresponding to the output electrical quantity according to the output electrical quantity and the multi-segment droop hysteresis surface; when the original power reference value is less than 0, obtaining a target power reference value equal to 0; when the original power reference value is greater than or equal to 0 and less than or equal to the power limit, obtaining a target power reference value equal to the original power reference value; when the original power reference value is greater than the power limit, obtaining a target power reference value equal to the power limit value.
  • a multi-segment droop hysteresis surface is used to represent the corresponding relationship between the output electrical quantity and the power limit, that is, the controller can obtain the power limit according to the output electrical quantity and the multi-segment droop hysteresis surface.
  • the controller obtains the target power reference value by comparing the power limit with the original power reference value of the power conversion circuit, which can be understood as limiting the original power reference value by the power limit to obtain the target power reference value. For example, the lowest value of the limit is 0, and the highest value is the power limit, that is, the target power reference value is greater than or equal to 0 and less than or equal to the power limit.
  • the target power reference value obtained by limiting is equal to 0; when the original power reference value is greater than or equal to 0 and less than or equal to the power limit, the target power reference value obtained by limiting is equal to the original power reference value; when the original power reference value is greater than the power limit, the target power reference value obtained by limiting is equal to the power limit.
  • the output power value of the power conversion circuit is controlled to be equal to the target power reference value, thereby achieving rapid adjustment of the output power of the power converter in the area under high light-to-energy ratio scenarios, thereby improving the reliability and safety of the power converter.
  • obtaining a power limit value corresponding to the output electrical quantity based on the output electrical quantity and a multi-segment droop hysteresis surface includes: when the output electrical quantity is greater than or equal to a first electrical quantity threshold value and less than a second electrical quantity threshold value, obtaining the power limit value corresponding to the output electrical quantity as a value corresponding to a hysteresis segment curve in the multi-segment droop hysteresis surface.
  • the power limit when the output electrical quantity is greater than or equal to the first electrical quantity threshold, the power limit can be obtained according to the multi-segment droop hysteresis surface.
  • the multi-segment droop hysteresis surface can include a hysteresis segment curve and N droop curves.
  • the power limit when the output electrical quantity is greater than or equal to the first electrical quantity threshold and less than the second electrical quantity threshold, the power limit can be the value corresponding to the hysteresis segment curve.
  • the hysteresis segment curve can avoid entering the power limit into the droop curve multiple times in a short period of time, provide sufficient time for the upper power scheduling, avoid large-scale up and down fluctuations in the output power, thereby avoiding repeated continuous oscillations of the output power of the power converter and improving system stability.
  • the method also includes: when the output electrical quantity is greater than or equal to a second electrical quantity threshold value and less than a third electrical quantity threshold value, obtaining a power limit value corresponding to the output electrical quantity as a value corresponding to a first section of a droop curve in a multi-section droop hysteresis surface; when the output electrical quantity is greater than or equal to a third electrical quantity threshold value and less than a fourth electrical quantity threshold value, obtaining a power limit value corresponding to the output electrical quantity as a value corresponding to a second section of a droop curve in a multi-section droop hysteresis surface; when the output electrical quantity is greater than or equal to an N+1th electrical quantity threshold value and less than an N+2th electrical quantity threshold value, obtaining a power limit value corresponding to the output electrical quantity as a value corresponding to an Nth section of a droop curve in a multi-section droop hysteresis
  • the power limit value when the output electrical quantity is greater than the second electrical quantity threshold, the power limit value enters the N-segment droop curve, and the power limit value can correspond to the value corresponding to a certain droop curve in the N-segment droop curve according to the size of the electrical quantity threshold.
  • Different power limits are adopted in different reference voltage intervals, and the power limit value is compared with the original power reference value of the power conversion circuit to obtain a target power reference value, and the output power value of the power conversion circuit is controlled to be equal to the target power reference value, so that the output power of the power converter in the area can be quickly adjusted in a high light-to-storage ratio scenario, thereby improving the reliability and safety of the power converter.
  • the power limit corresponding to the output electrical quantity is the value corresponding to N droop curves in a multi-segment droop hysteresis surface
  • the power limit corresponding to the first moment is less than or equal to the power limit corresponding to the second moment, and the first moment is later than the second moment.
  • the power limit values on adjacent time sequences only decrease and do not increase, which can avoid large-scale up and down fluctuations in the output power of the power converter, thereby avoiding repeated and continuous oscillations in the output power of the power converter and improving system stability.
  • the method further includes: when the time when the output electrical quantity is less than the second electrical quantity threshold reaches a first threshold, increasing the power limit value to a value corresponding to a hysteresis curve in a multi-segment droop hysteresis surface according to a preset time.
  • the power limit when it is detected that the output electrical quantity of the power converter tends to be normal, the power limit is restored. That is, when the time when the output electrical quantity is less than the second electrical quantity threshold reaches the first threshold, it can be said that the output electrical quantity of the power converter is in a normal state, and the power limit can be restored according to a predefined certain gradient, and the power limit is restored to the value corresponding to the hysteresis segment curve.
  • the predefined certain gradient can be understood as a preset period of time, and the power limit is increased to the value corresponding to the hysteresis segment curve in the multi-segment droop hysteresis surface within the preset time.
  • the method further includes: when the number of times that the output electrical quantity is greater than or equal to the second electrical quantity threshold exceeds the second threshold, increasing the preset time.
  • the speed of power limit recovery can be slowed down accordingly according to the number of times the N-segment droop curve is entered, so as to provide sufficient adjustment time for upper-layer power scheduling.
  • the target power reference value is a target active power reference value or a target reactive power reference value.
  • a third aspect provides a power supply system, the power supply system comprising a power supply unit, and a power converter provided in the first aspect or any possible implementation mode of the first aspect connected to the power supply unit (such as directly or indirectly), the power converter further connected to the AC Flow load.
  • the power supply unit is a photovoltaic array
  • the power converter is a photovoltaic power converter.
  • the photovoltaic power converter can convert the DC voltage provided by the photovoltaic array into an AC voltage, and supply power to the AC load based on the AC voltage.
  • the photovoltaic power converter includes a power conversion circuit and a controller
  • the controller can obtain a target power reference value of the power conversion circuit based on the output electrical quantity of the power conversion circuit and a multi-segment droop hysteresis loop surface.
  • the output power value of the power conversion circuit is controlled to be equal to the target power reference value, so that the output power of the power converter in the area can be quickly adjusted in a high light-to-storage ratio scenario, thereby improving the reliability and safety of the power converter.
  • the power supply unit is a wind turbine generator or an energy storage battery
  • the power converter is an energy storage power converter.
  • the energy storage power converter can convert the DC voltage provided by the wind turbine generator or the energy storage battery into an AC voltage, and supply power to the AC load based on the AC voltage.
  • the controller can obtain a target power reference value of the power conversion circuit based on the output electrical quantity of the power conversion circuit and a multi-segment droop hysteresis loop surface.
  • the output power value of the power conversion circuit is controlled to be equal to the target power reference value, so that the output power of the power converter in the area can be quickly adjusted in a high light-to-storage ratio scenario, thereby improving the reliability and power supply safety of the power supply system and making it more adaptable.
  • the power supply system further includes a DC combiner box, through which the power supply unit can be connected to the input end of the power converter.
  • the DC combiner box can combine the DC voltage provided by the power supply unit and output it to the power converter.
  • the power converter (such as a centralized power converter) can supply power to the AC load based on the combined DC voltage.
  • the power converter can quickly adjust the output power in the area under high light-to-storage ratio scenarios, the reliability and power supply safety of the power supply system can be improved, and the adaptability is stronger.
  • the power supply system further includes an energy storage converter, which can store the DC power provided by the power supply unit.
  • the energy storage converter can supply power to the DC load based on the stored electric energy.
  • the energy storage converter can also store excess electric energy provided to the power converter to achieve energy saving.
  • the power converter since the power converter can quickly adjust the output power in the area under the high light-to-energy ratio scenario and reduce the impact on the energy storage converter, the reliability and power supply safety of the power supply system can be improved, and the adaptability is stronger.
  • a controller is added to limit the output power of the power conversion circuit.
  • the input of the controller is the output electrical quantity of the power conversion circuit, and the output is the power limit.
  • the multi-segment droop hysteresis loop surface is used to represent the corresponding relationship between the output electrical quantity and the power limit, that is, the controller can obtain the power limit according to the output electrical quantity and the multi-segment droop hysteresis loop surface.
  • the power limit is compared with the original power reference value of the power conversion circuit to obtain a target power reference value, and the output power value of the power conversion circuit is controlled to be equal to the target power reference value, so that the output power of the power converter in the area can be quickly adjusted in a high light-to-storage ratio scenario, thereby improving the reliability and safety of the power converter.
  • FIG1 is a schematic diagram of an application scenario of a power converter provided by the present application.
  • FIG2 is a schematic diagram of a structure of a power supply system provided by the present application.
  • FIG3 is another schematic diagram of the structure of the power supply system provided by the present application.
  • FIG4 is a schematic diagram of a structure of a power converter provided by the present application.
  • FIG5 is a schematic diagram of a curve of power limit provided by the present application.
  • FIG6 is a schematic flow chart of a power control method for a power converter provided in the present application.
  • energy storage converters are usually used as voltage sources, and new energy converters such as photovoltaic converters and wind power converters are used as current sources to jointly supply power to the loads in the microgrid.
  • new energy converters such as photovoltaic converters and wind power converters are used as current sources to jointly supply power to the loads in the microgrid.
  • the capacity of the current source is much higher than the capacity of the voltage source, such as the installed capacity ratio of photovoltaic converters to energy storage converters is 2 or 3, or even higher, thus forming a local high photovoltaic-to-storage ratio scenario.
  • the high PV-to-storage ratio scenario in this application can be understood as a scenario where the installed capacity ratio of the new energy converter and the energy storage converter is greater than 1.
  • the energy storage converter switches from discharge to charging, and all the power of the high-ratio new energy converter is injected into the energy storage converter, raising the load voltage and frequency, which may cause damage to the energy storage converter during the transient process.
  • the power converter (an AC/DC converter) provided in this application is suitable for the new energy smart microgrid field, power transmission and distribution field or new energy
  • the invention can be applied in a variety of application fields (such as photovoltaic grid-connected field or wind grid-connected field), photovoltaic power generation field (such as photovoltaic power converter), wind power generation field, high-power converter field (such as converting DC voltage into high-power high-voltage AC power), or electric equipment field (such as various electric equipment), etc.
  • the specific application fields can be determined according to the actual application scenarios and are not limited here.
  • the power converter provided in the present application can be adapted to high-power power converter application scenarios and medium- and small-power power converter application scenarios, such as photovoltaic power supply application scenarios, wind power grid-connected power supply scenarios, electric vehicle charging scenarios or other application scenarios.
  • the photovoltaic power supply application scenario will be used as an example for explanation, and no further description will be given below.
  • Figure 1 is a schematic diagram of the application scenario of the power converter provided in the present application.
  • the application scenario may include a power supply unit, a positive DC bus, a negative DC bus and a power converter.
  • the power supply unit may be connected to the input end of the power converter through the positive DC bus and the negative DC bus, and the output end of the power converter may be used to connect an AC load.
  • the AC load may be an AC power grid or other.
  • the power supply unit may be a wind turbine, a photovoltaic array or an energy storage battery
  • the photovoltaic array here may be a photovoltaic module group
  • a photovoltaic module group may be composed of one or more photovoltaic groups connected in series and in parallel
  • a photovoltaic group string may be obtained by connecting one or more photovoltaic modules in series.
  • the photovoltaic modules here may be solar panels or photovoltaic panels, etc.
  • the controller can obtain a target power reference value of the power conversion circuit based on the output electrical quantity of the power conversion circuit and a multi-segment droop hysteresis loop surface.
  • the output power value of the power conversion circuit is controlled to be equal to the target power reference value, so that the output power of the power converter in the area can be quickly adjusted in a high light-to-storage ratio scenario, thereby improving the reliability and power supply safety of the power supply system, and having strong adaptability.
  • the power converter, the power control method of the power converter, the power supply system and the working principle thereof provided in the present application will be illustrated below in conjunction with Figures 2 to 6.
  • the power supply system including the power converter will be illustrated below, please refer to Figure 2,
  • Figure 2 is a schematic diagram of a power supply system provided by the present application.
  • the power supply system 10 includes a power supply unit 101 and a power converter 102 (such as the following power converter 40) connected to the power supply unit 101 (such as directly connected or indirectly connected), and the output end of the power converter can be connected (such as directly connected or indirectly connected) to an AC load.
  • the power converter 102 can convert the DC voltage provided by the power supply unit 101 into an AC voltage, and supply power to the AC load based on the AC voltage.
  • the controller can obtain a target power reference value of the power conversion circuit based on the output electrical quantity of the power conversion circuit and a multi-segment droop hysteresis loop surface, and control the output power value of the power conversion circuit to be equal to the target power reference value, so that the output power of the power converter in the region can be quickly adjusted in a high light storage ratio scenario, and the reliability and safety of the power converter can be improved.
  • the power supply unit 101 can be a photovoltaic array
  • the power converter 102 is a photovoltaic power converter.
  • the photovoltaic power converter can convert the DC voltage provided by the photovoltaic array into an AC voltage, and supply power to the AC load based on the AC voltage.
  • the controller can obtain a target power reference value of the power conversion circuit based on the output electrical quantity of the power conversion circuit and a multi-segment droop hysteresis loop surface, and control the output power value of the power conversion circuit to be equal to the target power reference value, thereby realizing the rapid adjustment of the output power of the power converter in the area in a high light-to-energy ratio scenario, and improving the reliability and safety of the power converter.
  • the power supply unit 101 can be a wind turbine generator or an energy storage battery
  • the power converter 102 is an energy storage power converter.
  • the energy storage power converter can convert the DC voltage provided by the wind turbine generator or the energy storage battery into an AC voltage, and supply power to the AC load based on the AC voltage.
  • the controller can obtain a target power reference value of the power conversion circuit based on the output electrical quantity of the power conversion circuit and a multi-segment droop hysteresis loop surface, and control the output power value of the power conversion circuit to be equal to the target power reference value, thereby realizing the rapid adjustment of the output power of the power converter in the area in a high light-to-storage ratio scenario, and improving the reliability and safety of the power converter.
  • the power supply system 10 shown in FIG. 2 further includes a DC combiner box 103, and the power supply unit 101 can be connected to the input end of the power converter 102 through the DC combiner box 103, and the output end of the power converter 102 can be connected (such as directly or indirectly) to an AC load.
  • the DC combiner box 103 can combine the DC voltage provided in the power supply unit 101 and output it to the power converter 102.
  • the power converter 102 (such as a centralized photovoltaic power converter) can supply power to the AC load based on the combined DC voltage.
  • the reliability and power supply safety of the power converter 102 are higher, the reliability and power supply safety of the power supply system 10 can be improved, and the adaptability is stronger.
  • the power supply system 10 further includes an energy storage converter 104, and the output end of the DC combiner box 103 can be connected to the input end of the power converter 102 and the input end of the energy storage converter 104 respectively, the output end of the power converter 102 can be connected to an AC load, and the output end of the energy storage converter 104 can be connected to an AC load and a DC load.
  • the energy storage converter 104 can store the DC power provided by the power supply unit 101, and in the process of supplying power to the DC load, the energy storage converter 104 can supply power to the DC load based on the stored electrical energy.
  • the energy storage converter 104 can also The excess electric energy provided to the power converter is stored to achieve energy saving. It can be understood that when the energy storage converter 104 supplies power to the AC load, the energy storage converter 104 and the AC load can be connected through an inverter, and the DC voltage provided by the energy storage converter is converted into an AC voltage through the inverter, and the AC load is powered based on the AC voltage.
  • the controller can obtain a target power reference value of the power conversion circuit based on the output electrical quantity of the power conversion circuit and a multi-segment droop hysteresis loop surface, and control the output power value of the power conversion circuit to be equal to the target power reference value, so that the output power of the power converter in the region can be quickly adjusted in a high light-to-storage ratio scenario, reducing the impact on the energy storage converter and improving the reliability and safety of the power converter.
  • FIG. 4 is a schematic diagram of a structure of a power converter provided by the present application.
  • the power converter 40 includes a controller 401 and a power conversion circuit 402, and the controller 401 is connected to the power conversion circuit 402.
  • the controller 401 is used to obtain a target power reference value P* of the power conversion circuit 402 based on the output electrical quantity Xd of the power conversion circuit 402 and a multi-segment droop hysteresis loop surface, and the controller 401 is also used to control the output power of the power conversion circuit 402 to be equal to the target power reference value P*.
  • the target power reference value P* may be a target active power reference value or a target reactive power reference value.
  • the output electrical quantity Xd can be understood as the electrical quantity of the AC load, that is, when the AC output terminal of the power converter 40 is connected to a grid-connected access point of the AC load, the electrical quantity between the AC output terminal of the power converter 40 and the grid-connected access point is obtained.
  • the output electrical quantity Xd can be an output voltage or an output frequency, etc.
  • the multi-segment droop hysteresis surface is used to represent the corresponding relationship between the output electrical quantity Xd and the power limit value Plmt, that is, the controller can obtain the power limit value Plmt according to the output electrical quantity Xd and the multi-segment droop hysteresis surface.
  • the controller 401 may perform low-pass filtering after collecting the output electrical quantity Xd of the power converter to obtain the output electrical quantity filter value Xd_flt . Based on the output electrical quantity filter value Xd_flt and the multi-segment droop hysteresis loop surface, the target power reference value P* of the power conversion circuit 402 is obtained.
  • the output electrical quantity Xd in the subsequent description may also be replaced by the output electrical quantity filter value Xd_flt .
  • the controller 401 is used to: obtain the power limit value Plmt corresponding to the output electrical quantity according to the output electrical quantity Xd and the multiple droop hysteresis loop surfaces.
  • the target power reference value P* is equal to 0; when the original power reference value Pref is greater than or equal to 0 and less than or equal to the power limit value Plmt, the target power reference value P* is equal to the original power reference value Pref; when the original power reference value Pref is greater than the power limit value Plmt, the target power reference value P* is equal to the power limit value Plmt.
  • the controller obtains the target power reference value P* by comparing the power limit value Plmt with the original power reference value Pref of the power conversion circuit. It can be understood that the target power reference value P* is obtained by limiting the original power reference value Pref by the power limit value Plmt. For example, the lowest value of the limit is 0, and the highest value is the power limit value Plmt, that is, the original target power reference value P* is greater than or equal to 0 and less than or equal to the power limit value Plmt.
  • the target power reference value P* when the original power reference value Pref is less than 0, the target power reference value P* is equal to 0 after clipping; when the original power reference value Pref is greater than or equal to 0 and less than or equal to the power limit value Plmt, the target power reference value P* is equal to the original power reference value Pref after clipping; when the original power reference value Pref is greater than the power limit value Plmt, the target power reference value P* is equal to the power limit value Plmt after clipping.
  • the output power value of the power conversion circuit is controlled to be equal to the target power reference value P*, so that the output power of the power converter 40 in the area can be quickly adjusted in a high light-to-energy ratio scenario, thereby improving the reliability and safety of the power converter.
  • the controller 401 may include a limiting module for limiting the original power reference value Pref by the power limit value Plmt to obtain the target power reference value P*.
  • the limiting module can be included in the controller 401, or can be outside the controller 401, that is, connected to the input end of the power conversion circuit 402. The embodiment of the present application does not limit the connection method of the limiting module.
  • the controller 401 is used to: when the output electrical quantity Xd is greater than or equal to the first electrical quantity threshold value X1 and less than the second electrical quantity threshold value X2 , obtain the power limit value Plmt corresponding to the output electrical quantity Xd as the value corresponding to the hysteresis segment curve in the multi-segment droop hysteresis surface.
  • the power limit value Plmt corresponding to the output electrical quantity Xd is obtained as the value corresponding to the first section of the droop curve in the multi-section droop hysteresis surface; when the output electrical quantity Xd is greater than or equal to the third electrical quantity threshold value X3 and less than the fourth electrical quantity threshold value X4 , the power limit value Plmt corresponding to the output electrical quantity Xd is obtained as the value corresponding to the second section of the droop curve in the multi-section droop hysteresis surface; ...; when the output electrical quantity Xd is greater than or equal to the N+1th electrical quantity threshold value XN+1 and less than the N+2th electrical quantity threshold value XN +2 , the power limit value Plmt corresponding to the output electrical quantity Xd is obtained as the value corresponding to the N
  • the power limit value Plmt can always be Pln as shown in the line segment ab in Figure 4, for example, Pln is a per-unit value of 1, which is represented by the rated power of the power converter 40, such as the rated active power.
  • the power limit value Plmt can be obtained according to the multi-segment droop hysteresis surface.
  • the multi-segment droop hysteresis surface may include a hysteresis segment curve and N droop curves.
  • the power limit value Plmt may be a value corresponding to the hysteresis segment curve, such as the line segment bc in FIG4 as the hysteresis segment, and the power limit value Plmt is still kept as the per-unit value 1.
  • the power limit value Plmt enters the N-segment droop curve, and the power limit value Plmt can correspond to the value of a certain droop curve in the N-segment droop curve according to the size of the electrical quantity threshold value.
  • the power limit Plmt corresponding to the output electrical quantity Xd is the value corresponding to the N-segment droop curve in the multi-segment droop hysteresis loop
  • the power limit Plmt corresponding to the first moment is less than or equal to the power limit Plmt corresponding to the second moment, wherein the first moment is later than the second moment.
  • the power limit Plmt on the adjacent time sequence only decreases but does not increase, which can avoid the output power of the power converter 40 from fluctuating up and down in a large range, thereby avoiding the output power of the power converter 40 from oscillating repeatedly and continuously, thereby improving the stability of the system.
  • the power limit Plmt corresponding to the output electrical quantity Xd is a value on any droop curve among cd, de, ef, ..., gh
  • the change of the adjacent values of the time sequence is approximately only decreasing but not increasing.
  • the value of Plmt is limited to P10.
  • the value of Plmt is also approximately only decreasing but not increasing.
  • the specific method can refer to the values on the above line segments cd, de, ef, ..., gh.
  • the controller 401 is also used to increase the power limit value Plmt to a value corresponding to the hysteresis curve in the multi-segment droop hysteresis surface according to a preset time when the time when the output electrical quantity Xd is less than the second electrical quantity threshold reaches a first threshold.
  • the power limit value Plmt is restored.
  • the predefined certain gradient can be understood as a preset period of time, and the power limit value Plmt is increased to a value corresponding to the hysteresis curve in the multi-segment droop hysteresis surface within a preset time.
  • the controller 401 is further configured to increase the above-mentioned preset time when the number of times the output electrical quantity Xd is greater than or equal to the second electrical quantity threshold exceeds the second threshold.
  • the gradient value can be reduced according to the number of times the N-segment droop hysteresis loop surface is entered, and the speed of recovery of the power limit value Plmt is correspondingly slowed down, thereby extending the recovery time, avoiding multiple entry and exit of the N-segment droop hysteresis loop surface in a short period of time, thereby avoiding output power oscillation, and also providing sufficient adjustment time for upper-layer power scheduling.
  • FIG. 5 is a curve diagram of the power limit provided in the present application.
  • ⁇ set to 0 and a custom gradient
  • the output electrical quantity suddenly increases and returns to normal, as shown in Figure 5
  • t ⁇ t1 the output electrical quantity is within the normal range, and Plmt is obtained according to the multi-segment droop hysteresis surface as the rated power of the power converter, which is equivalent to unlimited;
  • t ⁇ [t1, t2] the output electrical quantity suddenly increases, and a segmented decline curve appears according to the hysteresis characteristics of the multi-segment droop hysteresis surface;
  • t ⁇ [t2, t3] the output electrical quantity does not increase further, and Plmt remains constant;
  • a fast frequency and voltage regulation method based on a multi-segment droop hysteresis surface through a controller is proposed, which can avoid large-scale up and down fluctuations of transient output power;
  • a power oscillation suppression method based on an adaptive recovery gradient through a controller is proposed, which adaptively reduces the recovery gradient according to the number of times the droop hysteresis surface is entered, so as to avoid entering the droop hysteresis surface multiple times in a short period of time, thereby providing sufficient time for upper-level power scheduling;
  • a custom hysteresis segment timing recovery method is proposed, which reduces the influence of the droop hysteresis surface and improves the output power when the system is in a normal state range.
  • the power control method of the power converter is illustrated below. Please refer to Figure 6, which is a flow chart of the power control method of the power converter provided by the present application.
  • the power control method of the power converter provided by the present application is applicable to the controller in the power converter shown in Figure 4 above, and the controller is connected to the power conversion circuit in the power converter.
  • the power control method of the power converter provided by the present application includes the steps of:
  • S601 Obtaining a target power reference value of the power conversion circuit based on the output electrical quantity of the power conversion circuit and a plurality of droop hysteresis surfaces.
  • a controller is added to limit the output power of the power conversion circuit.
  • the input of the controller is the output electrical quantity of the power conversion circuit, and the output is the power limit.
  • the multi-segment droop hysteresis loop surface is used to represent the corresponding relationship between the output electrical quantity and the power limit, that is, the controller can obtain the power limit according to the output electrical quantity and the multi-segment droop hysteresis loop surface.
  • the power limit is compared with the original power reference value of the power conversion circuit to obtain the target power reference value.
  • obtaining the target power reference value of the power conversion circuit based on the output electrical quantity of the power conversion circuit and the multi-segment droop hysteresis surface includes: obtaining the power limit corresponding to the output electrical quantity according to the output electrical quantity and the multi-segment droop hysteresis surface; when the original power reference value is less than 0, obtaining the target power reference value equal to 0; when the original power reference value is greater than or equal to 0 and less than or equal to the power limit, obtaining the target power reference value equal to the original power reference value; when the original power reference value is greater than the power limit, obtaining the target power reference value equal to the power limit.
  • the multi-segment droop hysteresis surface is used to represent the corresponding relationship between the output electrical quantity and the power limit, that is, the controller can obtain the power limit according to the output electrical quantity and the multi-segment droop hysteresis surface.
  • the controller obtains the target power reference value by comparing the power limit with the original power reference value of the power conversion circuit, which can be understood as obtaining the target power reference value by limiting the original power reference value through the power limit. For example, the lowest value of the limit is 0, and the highest value is the power limit, that is, the target power reference value is greater than or equal to 0 and less than or equal to the power limit.
  • the target power reference value when the original power reference value is less than 0, the target power reference value is equal to 0 after clipping; when the original power reference value is greater than or equal to 0 and less than or equal to the power limit, the target power reference value is equal to the original power reference value after clipping; when the original power reference value is greater than the power limit, the target power reference value is equal to the power limit after clipping.
  • the output power value of the power conversion circuit is controlled to be equal to the target power reference value, so that the output power of the power converter in the area can be quickly adjusted in a high light-to-energy ratio scenario, thereby improving the reliability and safety of the power converter.
  • obtaining the power limit corresponding to the output electrical quantity according to the output electrical quantity and the multiple droop hysteresis surfaces includes: when the output electrical quantity is greater than or equal to the first electrical quantity threshold and less than the second electrical quantity threshold, obtaining the power limit corresponding to the output electrical quantity as the value corresponding to the hysteresis segment curve in the multiple droop hysteresis surfaces.
  • the power limit can be obtained according to the multiple droop hysteresis surfaces.
  • the multiple droop hysteresis surfaces may include a hysteresis segment curve and N droop curves.
  • the power limit when the output electrical quantity is greater than or equal to the first electrical quantity threshold and less than the second electrical quantity threshold, the power limit may be the value corresponding to the hysteresis segment curve. It can be understood that the hysteresis segment curve can avoid entering the power limit multiple times in a short period of time and entering the droop curve, providing sufficient time for the upper power scheduling, avoiding large-scale up and down fluctuations in the output power, thereby avoiding repeated continuous oscillations of the output power of the power converter and improving system stability.
  • the method further includes: when the output electrical quantity is greater than or equal to the second electrical quantity threshold and less than the third electrical quantity threshold, obtaining the power limit corresponding to the output electrical quantity as the value corresponding to the first droop curve in the multi-segment droop hysteresis loop surface; when the output electrical quantity is greater than or equal to the third electrical quantity threshold and less than the fourth electrical quantity threshold, obtaining the power limit corresponding to the output electrical quantity as the value corresponding to the second droop curve in the multi-segment droop hysteresis loop surface; when the output electrical quantity is greater than or equal to the N+1th electrical quantity threshold and less than the N+2th electrical quantity threshold, obtaining the power limit corresponding to the output electrical quantity as the value corresponding to the Nth droop curve in the multi-segment droop hysteresis loop surface, where N is a positive integer greater than or equal to 1.
  • the power limit enters the N-segment droop curve, and the power limit can correspond to the value corresponding to a certain droop curve in the N-segment droop curve according to the size of the electrical quantity threshold.
  • Different power limits are adopted in different reference voltage ranges, and the power limit is compared with the original power reference value of the power conversion circuit to obtain the target power reference value.
  • the output power value of the power conversion circuit is controlled to be equal to the target power reference value. This can achieve rapid adjustment of the output power of the power converter in the area under high light-to-energy ratio scenarios, thereby improving the reliability and safety of the power converter.
  • the power limit corresponding to the output electrical quantity is N droop curves corresponding to the multi-segment droop hysteresis loop.
  • the power limit corresponding to the first moment is less than or equal to the power limit corresponding to the second moment, and the first moment is later than the second moment.
  • the power limit values on adjacent time sequences only decrease and do not increase, which can avoid the output power of the power converter from fluctuating up and down in a large range, thereby avoiding repeated and continuous oscillation of the output power of the power converter and improving system stability.
  • the power limit when the time when the output electrical quantity is less than the second electrical quantity threshold reaches a first threshold, the power limit is increased to a value corresponding to the hysteresis segment curve in the multi-segment droop hysteresis surface according to a preset time.
  • the power limit is restored when it is detected that the output electrical quantity of the power converter tends to be normal. That is, when the time when the output electrical quantity is less than the second electrical quantity threshold reaches the first threshold, it can be said that the output electrical quantity of the power converter is in a normal state, and the power limit can be restored according to a predefined certain gradient, and the power limit is restored to a value corresponding to the hysteresis segment curve.
  • the predefined certain gradient can be understood as a preset period of time, and the power limit is increased to a value corresponding to the hysteresis segment curve in the multi-segment droop hysteresis surface within the preset time.
  • the preset time is increased.
  • the speed of power limit recovery can be slowed down accordingly according to the number of times the N-segment droop curve is entered, providing sufficient adjustment time for upper-layer power scheduling.
  • S602 Control the output power of the power conversion circuit to be equal to the target power reference value.
  • the output power of the power converter in the area can be quickly adjusted in a high light-to-energy ratio scenario, thereby improving the reliability and safety of the power converter.
  • the controller can obtain a power limit value according to the output electrical quantity of the power conversion circuit and the multi-segment droop hysteresis loop surface.
  • the power limit value is compared with the original power reference value of the power conversion circuit to obtain a target power reference value, and the output power value of the power conversion circuit is controlled to be equal to the target power reference value, so that the output power of the power converter in the area can be quickly adjusted in a high light-to-energy ratio scenario, thereby improving the reliability and safety of the power converter.

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Abstract

本申请提供了一种功率控制方法、功率变换器及供电***。功率变换器包括控制器和功率变换电路，控制器连接功率变换电路；控制器用于基于功率变换电路的输出电气量以及多段下垂滞环面得到功率变换电路的目标功率参考值；控制器还用于控制功率变换电路的输出功率值等于目标功率参考值。采用本申请，可以实现在高光储比场景下快速调节区域内的功率变换器的输出功率，避免功率变换器的输出功率反复持续振荡，提高功率变换器的可靠性和安全性。

Description

功率控制方法、功率变换器及供电***
本申请要求于2022年09月29日提交中国国家知识产权局、申请号为202211202008.7、申请名称为“功率控制方法、功率变换器及供电***”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及电子电力技术领域，尤其涉及一种功率控制方法、功率变换器及供电***。
背景技术
随着新能源技术的发展，在以新能源为主要电源的微电网场景中，通常以储能变换器作为电压源，光伏变换器、风力变换器等新能源变换器为电流源，共同向微电网内的负载供电。在微电网网架设计与新能源变换器容量配置时，会出现某个断路器控制的区域内，电流源的容量远高于电压源的容量，如光伏变换器与储能变换器装机容量比值为2或者3，甚至更高，从而形成局部高光储比场景。当微电网内发生大扰动或故障，导致高光储比区域的断路器断开时，电流源的输出功率将全部或大部分注入到电压源中，可能导致电压源过压过频，甚至过载，进而被损坏。
本申请的发明人在研究和实验过程中发现，在现有技术中，通过局部增加储能变换器的装机容量，避免出现高光储比场景，从而在区域断路器断开时，储能变换器有能力稳定电压与频率，不会发生过载。但该技术方案对微电网各区域装机容量的配置约束较大，无法因地制宜地灵活配置供电单元与储能变换器装机容量，且配置后的总装机容量较大，成本高。
发明内容
本申请提供一种功率控制方法、功率变换器及供电***，可以实现在高光储比场景下快速调节区域内的功率变换器的输出功率，提高功率变换器的可靠性和安全性。
第一方面，本申请提供了一种功率变换器，该功率变换器包括控制器和功率变换电路，控制器连接该功率变换电路。控制器可用于基于功率变换电路的输出电气量以及多段下垂滞环面得到功率变换电路的目标功率参考值；控制器还可用于控制功率变换电路的输出功率值等于目标功率参考值。
在本实施例提供的方案中，在功率变换电路的基础上，通过增加控制器来限制功率变换电路的输出功率。控制器的输入为功率变换电路的输出电气量，输出为功率限值，多段下垂滞环面用于表示输出电气量与功率限值的对应关系，即控制器可以根据输出电气量和多段下垂滞环面得到功率限值。将功率限值与功率变换电路的原功率参考值比较得到目标功率参考值，控制功率变换电路的输出功率值等于目标功率参考值，从而可以实现在高光储比场景下快速调节区域内的功率变换器的输出功率，提高功率变换器的可靠性和安全性。
作为一种可能的实施方式，控制器用于根据输出电气量以及多段下垂滞环面得到输出电气量对应的功率限值；在原功率参考值小于0时，得到目标功率参考值等于0；在原功率参考值大于或等于0且小于或等于功率限值时，得到目标功率参考值等于原功率参考值；在原功率参考值大于功率限值时，得到目标功率参考值等于功率限值。
在本实施例提供的方案中，多段下垂滞环面用于表示输出电气量与功率限值的对应关系，即控制器可以根据输出电气量和多段下垂滞环面得到功率限值。控制器通过比较功率限值与功率变换电路的原功率参考值得到目标功率参考值，可以理解为，通过功率限值对原功率参考值进行限幅得到目标功率参考值。例如限幅的最低值为0，最高值为功率限值，即目标功率参考值大于或等于0且小于或等于功率限值。具体地：在原功率参考值小于0时，经过限幅得到目标功率参考值等于0；在原功率参考值大于或等于0且小于或等于功率限值时，经过限幅得到目标功率参考值等于原功率参考值；在原功率参考值大于功率限值时，经过限幅得到目标功率参考值等于功率限值。通过对原功率参考值限幅得到目标功率参考值，控制功率变换电路的输出功率值等于目标功率参考值，从而可以实现在高光储比场景下快速调节区域内的功率变换器的输出功率，提高功率变换器的可靠性和安全性。
作为一种可能的实施方式，控制器用于在输出电气量大于或等于第一电气量阈值且小于第二电气量阈 值时，获取输出电气量对应的功率限值为多段下垂滞环面中的滞环段曲线对应的值。
在本实施例提供的方案中，在输出电气量大于或等于第一电气量阈值时，可以根据多段下垂滞环面得到功率限值。其中，多段下垂滞环面可以包括一段滞环段曲线和N段下垂曲线，具体地，在输出电气量大于或等于第一电气量阈值且小于第二电气量阈值时，功率限值可以为该滞环段曲线对应的值，可以理解，该段滞环段曲线可以避免短时间内多次进入功率限值进入下垂曲线，为上层功率调度提供充足的时间，避免输出功率大范围上下波动，从而可以避免功率变换器的输出功率反复持续振荡，提高***稳定性。
作为一种可能的实施方式，控制器用于在输出电气量大于或等于第二电气量阈值且小于第三电气量阈值时，获取输出电气量对应的功率限值为多段下垂滞环面中的第一段下垂曲线对应的值；在输出电气量大于或等于第三电气量阈值且小于第四电气量阈值时，获取输出电气量对应的功率限值为多段下垂滞环面中的第二段下垂曲线对应的值；当输出电气量大于或等于第N+1电气量阈值且小于第N+2电气量阈值时，获取输出电气量对应的功率限值为多段下垂滞环面中的第N段下垂曲线对应的值，N为大于或等于1的正整数。
在本实施例提供的方案中，在输出电气量大于第二电气量阈值时，功率限值进入N段下垂曲线，功率限值可以根据电气量阈值的大小对应N段下垂曲线中某段下垂曲线对应的值。在不同参考电压区间内采取不同的功率限值，将功率限值与功率变换电路的原功率参考值比较得到目标功率参考值，控制功率变换电路的输出功率值等于目标功率参考值，从而可以实现在高光储比场景下快速调节区域内的功率变换器的输出功率，提高功率变换器的可靠性和安全性。
作为一种可能的实施方式，在输出电气量对应的功率限值为多段下垂滞环面中的N段下垂曲线对应的值时，第一时刻对应的功率限值小于或等于第二时刻对应的功率限值，第一时刻晚于第二时刻。
在本实施例提供的方案中，在N段下垂曲线上，相邻时序上的功率限值只减不增，可以避免功率变换器的输出功率大范围上下波动，从而可以避免功率变换器的输出功率反复持续振荡，提高***稳定性。
作为一种可能的实施方式，控制器用于在输出电气量小于第二电气量阈值的时间达到第一阈值时，根据预设时间将功率限值增大至为多段下垂滞环面中滞环段曲线对应的值。
在本实施例提供的方案中，当检测到功率变换器的输出电气量趋于正常时，功率限值进行恢复。即在输出电气量小于第二电气量阈值的时间达到第一阈值时，可以说明功率变换器的输出电气量处于正常状态，可以根据预定义的一定梯度恢复功率限值，将功率限值恢复至为滞环段曲线对应的值。其中，预定义的一定梯度可以理解为预设一段时间，将功率限值在预设时间内增大至为多段下垂滞环面中滞环段曲线对应的值。
作为一种可能的实施方式，控制器与用于在输出电气量大于或等于第二电气量阈值的次数超过第二阈值时，增大预设时间。
在本实施例提供的方案中，可以根据进入N段下垂曲线的次数，相应减缓功率限值恢复的速度，为上层功率调度提供充足的调节时间。
作为一种可能的实施方式，目标功率参考值为目标有功功率参考值或者目标无功功率参考值。
第二方面，本申请提供了一种功率变换器的功率控制方法，该方法适用于功率变换器中的控制器，上述功率变换器中还包括功率变换电路，控制器连接功率变换电路。该方法可以包括：基于功率变换电路的输出电气量以及多段下垂滞环面得到功率变换电路的目标功率参考值；控制功率变换电路的输出功率值等于目标功率参考值。
在本实施例提供的方案中，在功率变换电路的基础上，通过增加控制器来限制功率变换电路的输出功率。控制器的输入为功率变换电路的输出电气量，输出为功率限值，多段下垂滞环面用于表示输出电气量与功率限值的对应关系，即控制器可以根据输出电气量和多段下垂滞环面得到功率限值。将功率限值与功率变换电路的原功率参考值比较得到目标功率参考值，控制功率变换电路的输出功率值等于目标功率参考值，从而可以实现在高光储比场景下快速调节区域内的功率变换器的输出功率，提高功率变换器的可靠性和安全性。
作为一种可能的实施方式，基于功率变换电路的输出电气量以及多段下垂滞环面得到功率变换电路的目标功率参考值包括：根据输出电气量以及多段下垂滞环面得到输出电气量对应的功率限值；在原功率参考值小于0时，得到目标功率参考值等于0；在原功率参考值大于或等于0且小于或等于功率限值时，得到目标功率参考值等于原功率参考值；在原功率参考值大于功率限值时，得到目标功率参考值等于功率限 值。
在本实施例提供的方案中，多段下垂滞环面用于表示输出电气量与功率限值的对应关系，即控制器可以根据输出电气量和多段下垂滞环面得到功率限值。控制器通过比较功率限值与功率变换电路的原功率参考值得到目标功率参考值，可以理解为，通过功率限值对原功率参考值进行限幅得到目标功率参考值。例如限幅的最低值为0，最高值为功率限值，即目标功率参考值大于或等于0且小于或等于功率限值。具体地：在原功率参考值小于0时，经过限幅得到目标功率参考值等于0；在原功率参考值大于或等于0且小于或等于功率限值时，经过限幅得到目标功率参考值等于原功率参考值；在原功率参考值大于功率限值时，经过限幅得到目标功率参考值等于功率限值。通过对原功率参考值限幅得到目标功率参考值，控制功率变换电路的输出功率值等于目标功率参考值，从而可以实现在高光储比场景下快速调节区域内的功率变换器的输出功率，提高功率变换器的可靠性和安全性。
作为一种可能的实施方式，根据输出电气量以及多段下垂滞环面得到输出电气量对应的功率限值包括：在输出电气量大于或等于第一电气量阈值且小于第二电气量阈值时，获取输出电气量对应的功率限值为多段下垂滞环面中的滞环段曲线对应的值。
在本实施例提供的方案中，在输出电气量大于或等于第一电气量阈值时，可以根据多段下垂滞环面得到功率限值。其中，多段下垂滞环面可以包括一段滞环段曲线和N段下垂曲线，具体地，在输出电气量大于或等于第一电气量阈值且小于第二电气量阈值时，功率限值可以为该滞环段曲线对应的值，可以理解，该段滞环段曲线可以避免短时间内多次进入功率限值进入下垂曲线，为上层功率调度提供充足的时间，避免输出功率大范围上下波动，从而可以避免功率变换器的输出功率反复持续振荡，提高***稳定性。
作为一种可能的实施方式，该方法还包括：在输出电气量大于或等于第二电气量阈值且小于第三电气量阈值时，获取输出电气量对应的功率限值为多段下垂滞环面中的第一段下垂曲线对应的值；在输出电气量大于或等于第三电气量阈值且小于第四电气量阈值时，获取输出电气量对应的功率限值为多段下垂滞环面中的第二段下垂曲线对应的值；当输出电气量大于或等于第N+1电气量阈值且小于第N+2电气量阈值时，获取输出电气量对应的功率限值为多段下垂滞环面中的第N段下垂曲线对应的值，N为大于或等于1的正整数。
在本实施例提供的方案中，在输出电气量大于第二电气量阈值时，功率限值进入N段下垂曲线，功率限值可以根据电气量阈值的大小对应N段下垂曲线中某段下垂曲线对应的值。在不同参考电压区间内采取不同的功率限值，将功率限值与功率变换电路的原功率参考值比较得到目标功率参考值，控制功率变换电路的输出功率值等于目标功率参考值，从而可以实现在高光储比场景下快速调节区域内的功率变换器的输出功率，提高功率变换器的可靠性和安全性。
作为一种可能的实施方式，在输出电气量对应的功率限值为多段下垂滞环面中的N段下垂曲线对应的值时，第一时刻对应的功率限值小于或等于第二时刻对应的功率限值，第一时刻晚于第二时刻。
在本实施例提供的方案中，在N段下垂曲线上，相邻时序上的功率限值只减不增，可以避免功率变换器的输出功率大范围上下波动，从而可以避免功率变换器的输出功率反复持续振荡，提高***稳定性。
作为一种可能的实施方式，该方法还包括：在输出电气量小于第二电气量阈值的时间达到第一阈值时，根据预设时间将功率限值增大至为多段下垂滞环面中的滞环段曲线对应的值。
在本实施例提供的方案中，当检测到功率变换器的输出电气量趋于正常时，功率限值进行恢复。即在输出电气量小于第二电气量阈值的时间达到第一阈值时，可以说明功率变换器的输出电气量处于正常状态，可以根据预定义的一定梯度恢复功率限值，将功率限值恢复至为滞环段曲线对应的值。其中，预定义的一定梯度可以理解为预设一段时间，将功率限值在预设时间内增大至为多段下垂滞环面中滞环段曲线对应的值。
作为一种可能的实施方式，该方法还包括：在输出电气量大于或等于第二电气量阈值的次数超过第二阈值时，增大预设时间。
在本实施例提供的方案中，可以根据进入N段下垂曲线的次数，相应减缓功率限值恢复的速度，为上层功率调度提供充足的调节时间。
作为一种可能的实施方式，目标功率参考值为目标有功功率参考值或者目标无功功率参考值。
第三方面提供一种供电***，该供电***包括供电单元，以及与所述供电单元连接(如直接连接或者间接连接)的上述第一方面或第一方面中任一种可能实施方式中提供的功率变换器，功率变换器还连接交 流负载。
作为一种可能的实施方式，供电单元为光伏阵列，功率变换器为光伏功率变换器。在对交流负载供电的过程中，光伏功率变换器可将光伏阵列提供的直流电压转换为交流电压，并基于交流电压对交流负载供电。在光伏功率变换器中包括功率变换电路和控制器的情况下，控制器可以基于功率变换电路的输出电气量以及多段下垂滞环面得到功率变换电路的目标功率参考值。控制功率变换电路的输出功率值等于目标功率参考值，从而可以实现在高光储比场景下快速调节区域内的功率变换器的输出功率，提高功率变换器的可靠性和安全性。
作为一种可能的实施方式，供电单元为风电发电机或者储能电池，功率变换器为储能功率变换器。在对交流负载供电的过程中，储能功率变换器可将风电发电机或者储能电池提供的直流电压转换为交流电压，并基于交流电压对交流负载供电。在储能功率变换器中包括功率变换电路和控制器的情况下，控制器可以基于功率变换电路的输出电气量以及多段下垂滞环面得到功率变换电路的目标功率参考值。控制功率变换电路的输出功率值等于目标功率参考值，从而可以实现在高光储比场景下快速调节区域内的功率变换器的输出功率，因此可提高供电***的可靠性和供电安全性，适应性更强。
作为一种可能的实施方式，上述供电***还包括直流汇流箱，供电单元可通过直流汇流箱连接功率变换器的输入端，在对交流负载供电的过程中，直流汇流箱可对供电单元提供的直流电压进行汇流并输出至功率变换器，这时，功率变换器(如集中式功率变换器)可基于汇流后的直流电压对交流负载供电。在此供电过程中，由于功率变换器在高光储比场景下可以快速调节区域内的输出功率，因此可提高供电***的可靠性和供电安全性，适应性更强。
作为一种可能的实施方式，上述供电***还包括储能变换器，储能变换器可将供电单元提供的直流电进行存储，在对直流负载供电的过程中，储能变换器可基于存储的电能对直流负载供电。储能变换器还可将提供给功率变换器的多余电能进行存储，以达到节能目的。在此供电过程中，由于功率变换器在高光储比场景下可以快速调节区域内的输出功率，减小对储能变换器的冲击，因此可提高供电***的可靠性和供电安全性，适应性更强。
在本申请中，在功率变换电路的基础上，通过增加控制器来限制功率变换电路的输出功率。控制器的输入为功率变换电路的输出电气量，输出为功率限值，多段下垂滞环面用于表示输出电气量与功率限值的对应关系，即控制器可以根据输出电气量和多段下垂滞环面得到功率限值。将功率限值与功率变换电路的原功率参考值比较得到目标功率参考值，控制功率变换电路的输出功率值等于目标功率参考值，从而可以实现在高光储比场景下快速调节区域内的功率变换器的输出功率，提高功率变换器的可靠性和安全性。
附图说明
图1是本申请提供的功率变换器的应用场景示意图；
图2是本申请提供的供电***的一结构示意图；
图3是本申请提供的供电***的另一结构示意图；
图4是本申请提供的功率变换器的一结构示意图；
图5是本申请提供的功率限值的一曲线示意图；
图6是本申请提供的功率变换器的功率控制方法的流程示意图。
具体实施方式
随着新能源技术的发展，在以新能源为主要电源的微电网场景中，通常以储能变换器作为电压源，光伏变换器、风力变换器等新能源变换器为电流源，共同向微电网内的负载供电。在微电网网架设计与新能源变换器容量配置时，会出现某个断路器控制的区域内，电流源的容量远高于电压源的容量，如光伏变换器与储能变换器装机容量比值为2或者3，甚至更高，从而形成局部高光储比场景。当微电网内发生大扰动或故障，导致高光储比区域的断路器断开时，电流源的输出功率将全部或大部分注入到电压源中，可能导致电压源过压过频，甚至过载，进而被损坏。
本申请可以应用于微电网中的高光储比场景。本申请中的高光储比场景，可以理解为，新能源变换器与储能变换器的装机容量比值大于1。在新能源变换器以及储能变换器满功率放电、负荷突切的场景下，储能变换器由放电转充电，高比例新能源变换器的所有功率注入储能变换器，抬高负载电压与频率，暂态过程中可能导致储能变换器损坏。
本申请提供的功率变换器(一种交直流变换器)适用于新能源智能微网领域、输配电领域或者新能源 领域(如光伏并网领域或者风力并网领域)、光伏发电领域(如光伏功率变换器)，或者风力发电领域，或者大功率变换器领域(如将直流电压转换为大功率的高压交流电)，或者电动设备领域(如多种电动设备)等多种应用领域，具体可根据实际应用场景确定，在此不做限制。
本申请提供的功率变换器可适配于大功率的功率变换器应用场景以及中小功率的功率变换器应用场景，比如，光伏供电应用场景、风力并网供电场景、电动汽车充电场景或者其它应用场景，下面将以光伏供电应用场景为例进行说明，以下不再赘述。请一并参见图1，图1是本申请提供的功率变换器的应用场景示意图。如图1所示，该应用场景可以包括供电单元、正直流母线、负直流母线和功率变换器，供电单元可通过正直流母线和负直流母线连接功率变换器的输入端，功率变换器的输出端可用于连接交流负载。可选地，交流负载可以是交流电网，也可以是其它。其中，供电单元可以为风力发电机、光伏阵列或者储能电池，这里的光伏阵列可以为光伏组件组，一个光伏组件组可以由一个或者多个光伏组串并联组成，一个光伏组串可以由一个或者多个光伏组件串联得到。这里的光伏组件可为太阳能电池板或者光伏板等。功率变换器中包括功率变换电路和控制器的情况下，控制器可以基于功率变换电路的输出电气量以及多段下垂滞环面得到功率变换电路的目标功率参考值。控制功率变换电路的输出功率值等于目标功率参考值，从而可以实现在高光储比场景下快速调节区域内的功率变换器的输出功率，因此可提高供电***的可靠性和供电安全性，适应性强。下面将结合图2至图6对本申请提供的功率变换器、功率变换器的功率控制方法以及供电***及其工作原理进行示例说明。
在一些可行的实施方式中，下面将对包含功率变换器的供电***进行示例说明，请一并参见图2，图2是本申请提供的供电***的一结构示意图。如图2所示，供电***10中包括供电单元101以及与供电单元101连接(如直接连接或者间接连接)的功率变换器102(如下述功率变换器40)，且功率变换器的输出端可以连接(如直接连接或者间接连接)交流负载。在对交流负载供电的过程中，功率变换器102可将供电单元101提供的直流电压转换为交流电压，并基于交流电压对交流负载供电。在功率变换器102中包括控制器和功率变换电路的情况下，控制器可基于功率变换电路的输出电气量以及多段下垂滞环面得到功率变换电路的目标功率参考值，控制功率变换电路的输出功率值等于目标功率参考值，从而可以实现在高光储比场景下快速调节区域内的功率变换器的输出功率，提高功率变换器的可靠性和安全性。
其中，供电单元101可以为光伏阵列，功率变换器102为光伏功率变换器。在对交流负载供电的过程中，光伏功率变换器可将光伏阵列提供的直流电压转换为交流电压，并基于交流电压对交流负载供电。在光伏功率变换器中包括控制器和功率变换电路的情况下，控制器可基于功率变换电路的输出电气量以及多段下垂滞环面得到功率变换电路的目标功率参考值，控制功率变换电路的输出功率值等于目标功率参考值，从而可以实现在高光储比场景下快速调节区域内的功率变换器的输出功率，提高功率变换器的可靠性和安全性。
其中，供电单元101可以为风电发电机或者储能电池，功率变换器102为储能功率变换器。在对交流负载供电的过程中，储能功率变换器可将风电发电机或者储能电池提供的直流电压转换为交流电压，并基于交流电压对交流负载供电。在储能功率变换器中包括控制器和功率变换电路的情况下，控制器可基于功率变换电路的输出电气量以及多段下垂滞环面得到功率变换电路的目标功率参考值，控制功率变换电路的输出功率值等于目标功率参考值，从而可以实现在高光储比场景下快速调节区域内的功率变换器的输出功率，提高功率变换器的可靠性和安全性。
在一些可行的实施方式中，上述图2所示的供电***10还包括直流汇流箱103，上述供电单元101可通过直流汇流箱103连接功率变换器102的输入端，功率变换器102的输出端可连接(如直接连接或者间接连接)交流负载。在对交流负载供电的过程中，直流汇流箱103可对供电单元101中提供的直流电压进行汇流并输出至功率变换器102，这时，功率变换器102(如集中式光伏功率变换器)可基于汇流后的直流电压对交流负载供电。在此供电过程中，由于功率变换器102的可靠性和供电安全性更高，因此可提高供电***10的可靠性和供电安全性，适应性更强。
可选的，请一并参见图3，图3是本申请提供的供电***的另一结构示意图。在一些可行的实施方式中，如图3所示，上述供电***10还包括储能变换器104，上述直流汇流箱103的输出端可以分别连接功率变换器102的输入端和储能变换器104的输入端，功率变换器102的输出端可连接交流负载，储能变换器104的输出端可连接交流负载和直流负载。储能变换器104可将供电单元101提供的直流电进行存储，在对直流负载供电的过程中，储能变换器104可基于存储的电能对直流负载供电。储能变换器104还可将 提供给功率变换器的多余电能进行存储，以达到节能目的。可以理解，在储能变换器104为交流负载供电时，储能变换器104与交流负载之间可通过逆变器进行连接，通过逆变器将储能变换器的提供的直流电压转换为交流电压，并基于交流电压对交流负载供电。在功率变换器102中包括控制器和功率变换电路的情况下，控制器可基于功率变换电路的输出电气量以及多段下垂滞环面得到功率变换电路的目标功率参考值，控制功率变换电路的输出功率值等于目标功率参考值，从而可以实现在高光储比场景下快速调节区域内的功率变换器的输出功率，减小对储能变换器的冲击，提高功率变换器的可靠性和安全性。
参见图4，图4是本申请提供的功率变换器的一结构示意图。如图4所示，功率变换器40包括控制器401和功率变换电路402，控制器401连接功率变换电路402。其中，控制器401用于基于功率变换电路402的输出电气量Xd以及多段下垂滞环面得到功率变换电路402的目标功率参考值P*，控制器401还用于控制功率变换电路402的输出功率等于目标功率参考值P*。
需要说明的是，目标功率参考值P*可以为目标有功功率参考值或者目标无功功率参考值。
输出电气量Xd，可以理解为是交流负载的电气量，即在功率变换器40的交流输出端与交流负载的一个并网接入点相连时，获取的功率变换器40的交流输出端与所述并网接入点之间的电气量。输出电气量Xd可以为输出电压或者输出频率等。可以理解，多段下垂滞环面用于表示输出电气量Xd与功率限值Plmt的对应关系，即控制器可以根据输出电气量Xd和多段下垂滞环面得到功率限值Plmt。
可选地，控制器401采集功率变换器的输出电气量Xd后可以进行低通滤波，得到输出电气量滤波值Xd_flt。基于该输出电气量滤波值Xd_flt以及多段下垂滞环面得到功率变换电路402的目标功率参考值P*。后续描述中的输出电气量Xd也可以替换为输出电气量滤波值Xd_flt。
在一些可行的实施方式中，控制器401用于：根据输出电气量Xd以及多段下垂滞环面得到输出电气量对应的功率限值Plmt。在原功率参考值Pref小于0时，得到目标功率参考值P*等于0；在原功率参考值Pref大于或等于0且小于或等于功率限值Plmt时，得到目标功率参考值P*等于原功率参考值Pref；在原功率参考值Pref大于功率限值Plmt时，得到目标功率参考值P*等于功率限值Plmt。控制器通过比较功率限值Plmt与功率变换电路的原功率参考值Pref得到目标功率参考值P*，可以理解为，通过功率限值Plmt对原功率参考值Pref进行限幅得到目标功率参考值P*。例如限幅的最低值为0，最高值为功率限值Plmt，即原目标功率参考值P*大于或等于0且小于或等于功率限值Plmt。具体地：在原功率参考值Pref小于0时，经过限幅得到目标功率参考值P*等于0；在原功率参考值Pref大于或等于0且小于或等于功率限值Plmt时，经过限幅得到目标功率参考值P*等于原功率参考值Pref；在原功率参考值Pref大于功率限值Plmt时，经过限幅得到目标功率参考值P*等于功率限值Plmt。通过对原功率参考值Pref限幅得到目标功率参考值P*，控制功率变换电路的输出功率值等于目标功率参考值P*，从而可以实现在高光储比场景下快速调节区域内的功率变换器40的输出功率，提高功率变换器的可靠性和安全性。
可选地，控制器401可以包括限幅模块，用于通过功率限值Plmt对原功率参考值Pref进行限幅得到目标功率参考值P*。可以理解，限幅模块可以包含在控制器401中，也可以在控制器401外，即连接在功率变换电路402的输入端，本申请实施例对限幅模块的连接方式不作限定。
在一些可行的实施方式中，控制器401用于：在输出电气量Xd大于或等于第一电气量阈值X1且小于第二电气量阈值X2时，获取输出电气量Xd对应的功率限值Plmt为多段下垂滞环面中的滞环段曲线对应的值。在输出电气量Xd大于或等于第二电气量阈值X2且小于第三电气量阈值X3时，获取输出电气量Xd对应的功率限值Plmt为多段下垂滞环面中的第1段下垂曲线对应的值；在输出电气量Xd大于或等于第三电气量阈值X3且小于第四电气量阈值X4时，获取输出电气量Xd对应的功率限值Plmt为多段下垂滞环面中的第2段下垂曲线对应的值；…；在输出电气量Xd大于或等于第N+1电气量阈值XN+1且小于第N+2电气量阈值XN+2时，获取输出电气量Xd对应的功率限值Plmt为多段下垂滞环面中的第N段下垂曲线对应的值，N为大于或等于1的正整数。
可以理解，在输出电气量Xd小于第一电气量阈值X1时，功率限值Plmt可始终在如图4中的线段ab取值为Pln，例如Pln为标幺值1，表示为功率变换器40的额定功率，如额定有功功率。
在输出电气量Xd大于或等于第一电气量阈值X1时，可以根据多段下垂滞环面得到功率限值Plmt。其中，多段下垂滞环面可以包括一段滞环段曲线和N段下垂曲线。例如，在输出电气量Xd大于或等于第一电气量阈值X1且小于第二电气量阈值X2时，功率限值Plmt可以为该滞环段曲线对应的值，如图4中的线段bc作为滞环段，仍保持功率限值Plmt为标幺值1。
在输出电气量Xd大于第二电气量阈值X2时，功率限值Plmt进入N段下垂曲线，功率限值Plmt可以根据电气量阈值的大小对应N段下垂曲线中某段下垂曲线对应的值。例如，在输出电气量Xd大于或等于第二电气量阈值X2且小于第三电气量阈值X3时，输出电气量Xd对应的功率限值Plmt为N段下垂曲线中的第1段下垂曲线对应的值，即输出电气量Xd对应的功率限值Plmt由如图4中的线段cd决定，取值范围Pln-1～Pln，Pln-1为预定义的当Xd＝X3时的功率限值。在输出电气量Xd大于或等于第三电气量阈值X3且小于第四电气量阈值X4时，输出电气量Xd对应的功率限值Plmt为N段下垂曲线中的第2段下垂曲线对应的值，即输出电气量Xd对应的功率限值Plmt由如图4中的线段de决定，取值范围Pln-2～Pln-1，Pln-2为预定义的当Xd＝X4时的功率限值。…在输出电气量Xd大于或等于第N+1电气量阈值XN+1且小于第N+2电气量阈值XN+2时，输出电气量Xd对应的功率限值Plmt为N段下垂曲线中的第N段下垂曲线对应的值，即输出电气量Xd对应的功率限值Plmt由如图4中的线段gh决定，取值范围Pl0～Pl1，Pl1为预定义的当Xd＝XN+1时的功率限值，Pl0为预定义的当Xd＝XN+2时的功率限值。
在一些可行的实施方式中，在输出电气量Xd对应的功率限值Plmt为多段下垂滞环面中的N段下垂曲线对应的值时，第一时刻对应的功率限值Plmt小于或等于第二时刻对应的功率限值Plmt，其中第一时刻晚于第二时刻。可以理解，在N段下垂曲线上，相邻时序上的功率限值Plmt只减不增，可以避免功率变换器40的输出功率大范围上下波动，从而可以避免功率变换器40的输出功率反复持续振荡，提高***稳定性。结合图4进行进一步说明，当输出电气量Xd对应的功率限值Plmt为cd、de、ef、…、gh中任一下垂曲线上取值时，时序相邻值的变化近似于只减不增。举例说明，设t1＜t2＜t3，若Xd(t2)＞Xd(t1)，则Plmt(t2)＜Plmt(t1)。若Xd(t3)＜Xd(t2)，Plmt(t3)并不取线段cd、de、ef、…、gh上的值，而是按照Plmt(t3)-Plmt(t2)≤ε取值，其中ε为预定值，用于避免电压波动时，Plmt的取值大范围波动。当设定ε为0时，下垂曲线cd、de、ef、…、gh上的Plmt的取值只减不增。以Xd(t1)＝X3为例，当Xd(t2)，Xd(t3)＜X3时，Plmt(t2)，Plmt(t3)将在水平线du上取值。
当输出电气量Xd大于XN+2时，Plmt的取值被限定为Pl0。当时序上后续输出电气量Xd小于XN+2时，Plmt的取值也近似于只减不增。具体方式可以参考上述线段cd、de、ef、…、gh上的取值情况。
从上述描述可以看出，当发生Xd＞X2后，Plmt将在N段下垂滞环面bcdefghiub中取值，平面内的所有点，都可能取到。
在一些可行的实施方式中，控制器401，还用于在输出电气量Xd小于第二电气量阈值的时间达到第一阈值时，根据预设时间将功率限值Plmt增大至为多段下垂滞环面中的滞环段曲线对应的值。当检测到功率变换器40的输出电气量Xd趋于正常时，功率限值Plmt进行恢复。即在输出电气量Xd小于第二电气量阈值的时间达到第一阈值时，可以说明功率变换器40的输出电气量Xd处于正常状态，可以根据预定义的一定梯度恢复功率限值Plmt，将功率限值Plmt恢复至为滞环段曲线对应的值。其中，预定义的一定梯度可以理解为预设一段时间，将功率限值Plmt在预设时间内增大至为多段下垂滞环面中滞环段曲线对应的值。结合图4进一步说明，当***恢复正常或Xd＜X2时，Plmt需要退出该下垂滞环面。若X1＜Xd＜X2且持续时间达到预定值，则以一定梯度恢复Plmt的取值，直到恢复至最大值Pln；若Xd＜X1，则等待预定义时间后，以一定梯度恢复Plmt的取值，直到恢复至最大值Pln，其中，预定义时间可以是大于或等于0的时间。
可以理解地，在Plmt以一定梯度恢复到最大值的过程中，若Xd＞X2，则再次进入N段下垂滞环面bcdefghiub，进行Plmt的调节。需要说明的是，一定梯度可以是预先定义的固定梯度，也可以是根据一定规则的自适应梯度。
进一步可选地，在一些可行的实施方式中，控制器401，还用于在输出电气量Xd大于或等于第二电气量阈值的次数超过第二阈值时，增大上述预设时间。可以根据进入N段下垂滞环面的次数，减小梯度值，相应减缓功率限值Plmt恢复的速度，从而延长恢复时间，避免短时间内多次进出N段下垂滞环面，进而避免输出功率振荡，也可以为上层功率调度提供充足的调节时间。
请参见图5，图5是本申请提供的功率限值的一曲线示意图。以设定ε为0且自定义梯度，当输出电气量突增至恢复正常时，如图5所示，当t＜t1时，输出电气量在正常范围内，根据多段下垂滞环面得到Plmt为功率变换器的额定功率，等价于不限幅；当t∈[t1,t2]时，输出电气量突增，根据多段下垂滞环面的滞环特性出现分段下降曲线；当t∈[t2,t3]时，输出电气量没有进一步增加，Plmt维持恒定；当t∈[t3,t4]时，输出电气量恢复正常，Plmt根据预定义的梯度恢复；在t＝t4时刻，输出电气量突增，再次进入多段下垂滞环面；当t∈[t4,t5]时，输出电气量没有进一步增加，Plmt维持恒定；当t∈[t5,t6]时，输出电气量恢复正常，Plmt根据自适应梯度恢复至最大值；当t＞t6时，输出电气量在正常范围内，Plmt为功率变换器的 额定功率，等价于不限幅。
在本申请实施例提供的方案中，提出通过控制器的基于多段下垂滞环面的快速调频调压方法，可以避免暂态输出功率大范围上下波动；提出通过控制器的基于自适应恢复梯度的功率振荡抑制方法，根据进入下垂滞环面的次数，自适应减小恢复梯度，避免短时间内多次进入下垂滞环面，为上层功率调度提供充足的时间；提出自定义滞环段定时恢复方法，在***处于正常状态区间时，减小下垂滞环面的影响，提高输出功率。
下面对功率变换器的功率控制方法进行示例说明，请一并参见图6，图6是本申请提供的功率变换器的功率控制方法的流程示意图。本申请提供的功率变换器的功率控制方法适用于上述图4所示的功率变换器中的控制器，该控制器连接功率变换器中的功率变换电路。如图6所示，本申请提供的功率变换器的功率控制方法包括步骤：
S601：基于功率变换电路的输出电气量以及多段下垂滞环面得到功率变换电路的目标功率参考值。
在功率变换电路的基础上，通过增加控制器来限制功率变换电路的输出功率。控制器的输入为功率变换电路的输出电气量，输出为功率限值，多段下垂滞环面用于表示输出电气量与功率限值的对应关系，即控制器可以根据输出电气量和多段下垂滞环面得到功率限值。将功率限值与功率变换电路的原功率参考值比较得到目标功率参考值。
在一些可行的实施方式中，基于功率变换电路的输出电气量以及多段下垂滞环面得到功率变换电路的目标功率参考值包括：根据输出电气量以及多段下垂滞环面得到输出电气量对应的功率限值；在原功率参考值小于0时，得到目标功率参考值等于0；在原功率参考值大于或等于0且小于或等于功率限值时，得到目标功率参考值等于原功率参考值；在原功率参考值大于功率限值时，得到目标功率参考值等于功率限值。多段下垂滞环面用于表示输出电气量与功率限值的对应关系，即控制器可以根据输出电气量和多段下垂滞环面得到功率限值。控制器通过比较功率限值与功率变换电路的原功率参考值得到目标功率参考值，可以理解为，通过功率限值对原功率参考值进行限幅得到目标功率参考值。例如限幅的最低值为0，最高值为功率限值，即目标功率参考值大于或等于0且小于或等于功率限值。具体地：在原功率参考值小于0时，经过限幅得到目标功率参考值等于0；在原功率参考值大于或等于0且小于或等于功率限值时，经过限幅得到目标功率参考值等于原功率参考值；在原功率参考值大于功率限值时，经过限幅得到目标功率参考值等于功率限值。通过对原功率参考值限幅得到目标功率参考值，控制功率变换电路的输出功率值等于目标功率参考值，从而可以实现在高光储比场景下快速调节区域内的功率变换器的输出功率，提高功率变换器的可靠性和安全性。
在一些可行的实施方式中，根据输出电气量以及多段下垂滞环面得到输出电气量对应的功率限值包括：在输出电气量大于或等于第一电气量阈值且小于第二电气量阈值时，获取输出电气量对应的功率限值为多段下垂滞环面中的滞环段曲线对应的值。在输出电气量大于或等于第一电气量阈值时，可以根据多段下垂滞环面得到功率限值。其中，多段下垂滞环面可以包括一段滞环段曲线和N段下垂曲线，具体地，在输出电气量大于或等于第一电气量阈值且小于第二电气量阈值时，功率限值可以为该滞环段曲线对应的值，可以理解，该段滞环段曲线可以避免短时间内多次进入功率限值进入下垂曲线，为上层功率调度提供充足的时间，避免输出功率大范围上下波动，从而可以避免功率变换器的输出功率反复持续振荡，提高***稳定性。
在一些可行的实施方式中，该方法还包括：在输出电气量大于或等于第二电气量阈值且小于第三电气量阈值时，获取输出电气量对应的功率限值为多段下垂滞环面中的第一段下垂曲线对应的值；在输出电气量大于或等于第三电气量阈值且小于第四电气量阈值时，获取输出电气量对应的功率限值为多段下垂滞环面中的第二段下垂曲线对应的值；当输出电气量大于或等于第N+1电气量阈值且小于第N+2电气量阈值时，获取输出电气量对应的功率限值为多段下垂滞环面中的第N段下垂曲线对应的值，N为大于或等于1的正整数。在输出电气量大于第二电气量阈值时，功率限值进入N段下垂曲线，功率限值可以根据电气量阈值的大小对应N段下垂曲线中某段下垂曲线对应的值。在不同参考电压区间内采取不同的功率限值，将功率限值与功率变换电路的原功率参考值比较得到目标功率参考值，控制功率变换电路的输出功率值等于目标功率参考值，从而可以实现在高光储比场景下快速调节区域内的功率变换器的输出功率，提高功率变换器的可靠性和安全性。
在一些可行的实施方式中，在输出电气量对应的功率限值为多段下垂滞环面中的N段下垂曲线对应 的值时，第一时刻对应的功率限值小于或等于第二时刻对应的功率限值，第一时刻晚于第二时刻。在N段下垂曲线上，相邻时序上的功率限值只减不增，可以避免功率变换器的输出功率大范围上下波动，从而可以避免功率变换器的输出功率反复持续振荡，提高***稳定性。
在一些可行的实施方式中，在输出电气量小于第二电气量阈值的时间达到第一阈值时，根据预设时间将功率限值增大至为多段下垂滞环面中的滞环段曲线对应的值。当检测到功率变换器的输出电气量趋于正常时，功率限值进行恢复。即在输出电气量小于第二电气量阈值的时间达到第一阈值时，可以说明功率变换器的输出电气量处于正常状态，可以根据预定义的一定梯度恢复功率限值，将功率限值恢复至为滞环段曲线对应的值。其中，预定义的一定梯度可以理解为预设一段时间，将功率限值在预设时间内增大至为多段下垂滞环面中滞环段曲线对应的值。
在一些可行的实施方式中，在输出电气量大于或等于第二电气量阈值的次数超过第二阈值时，增大预设时间。可以根据进入N段下垂曲线的次数，相应减缓功率限值恢复的速度，为上层功率调度提供充足的调节时间。
S602：控制功率变换电路的输出功率等于目标功率参考值。
控制功率变换电路的输出功率值等于目标功率参考值，通过闭环控制功率变换电路的输出功率，可以实现在高光储比场景下快速调节区域内的功率变换器的输出功率，提高功率变换器的可靠性和安全性。
具体实现中，本申请提供的功率变换器的控制方法中控制器所执行的更多操作可参见上述图4所示的功率变换器40及其工作原理中控制器401所执行的实现方式，在此不再赘述。
在本申请提供的方法中，控制器可根据功率变换电路的输出电气量和多段下垂滞环面得到功率限值。将功率限值与功率变换电路的原功率参考值比较得到目标功率参考值，控制功率变换电路的输出功率值等于目标功率参考值，从而可以实现在高光储比场景下快速调节区域内的功率变换器的输出功率，提高功率变换器的可靠性和安全性。
以上所述，仅为本发明的具体实施方式，但本发明的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本发明揭露的技术范围内，可轻易想到变化或替换，都应涵盖在本发明的保护范围之内。因此，本发明的保护范围应以所述权利要求的保护范围为准。

Claims (18)

  1. 一种功率变换器，其特征在于，所述功率变换器包括控制器和功率变换电路，所述控制器连接所述功率变换电路；
    所述控制器用于基于所述功率变换电路的输出电气量以及多段下垂滞环面得到所述功率变换电路的目标功率参考值；
    所述控制器，还用于控制所述功率变换电路的输出功率值等于所述目标功率参考值。
  2. 根据权利要求1所述的功率变换器，其特征在于，所述控制器，用于：
    根据所述输出电气量以及多段下垂滞环面得到所述输出电气量对应的功率限值；
    在原功率参考值小于0时，得到所述目标功率参考值等于0；
    在所述原功率参考值大于或等于0且小于或等于功率限值时，得到所述目标功率参考值等于所述原功率参考值；
    在所述原功率参考值大于所述功率限值时，得到所述目标功率参考值等于所述功率限值。
  3. 根据权利要求2所述的功率变换器，其特征在于，所述控制器，用于在所述输出电气量大于或等于第一电气量阈值且小于第二电气量阈值时，获取所述输出电气量对应的功率限值为所述多段下垂滞环面中的滞环段曲线对应的值。
  4. 根据权利要求3所述的功率变换器，其特征在于，所述控制器，用于：
    在所述输出电气量大于或等于所述第二电气量阈值且小于第三电气量阈值时，获取所述输出电气量对应的功率限值为所述多段下垂滞环面中的第一段下垂曲线对应的值；
    在所述输出电气量大于或等于所述第三电气量阈值且小于第四电气量阈值时，获取所述输出电气量对应的功率限值为所述多段下垂滞环面中的第二段下垂曲线对应的值；
    当所述输出电气量大于或等于第N+1电气量阈值且小于第N+2电气量阈值时，获取所述输出电气量对应的功率限值为所述多段下垂滞环面中的第N段下垂曲线对应的值，N为大于或等于1的正整数。
  5. 根据权利要求4所述的功率变换器，其特征在于，在所述输出电气量对应的功率限值为所述多段下垂滞环面中的N段下垂曲线对应的值时，第一时刻对应的功率限值小于或等于第二时刻对应的功率限值，所述第一时刻晚于所述第二时刻。
  6. 根据权利要求3-5任一所述的功率变换器，其特征在于，所述控制器，用于在所述输出电气量小于所述第二电气量阈值的时间达到第一阈值时，根据预设时间将功率限值增大至为所述多段下垂滞环面中的滞环段曲线对应的值。
  7. 根据权利要求6所述的功率变换器，其特征在于，所述控制器，用于在所述输出电气量大于或等于所述第二电气量阈值的次数超过第二阈值时，增大所述预设时间。
  8. 根据权利要求1-7任一所述的功率变换器，其特征在于，所述目标功率参考值为目标有功功率参考值或者目标无功功率参考值。
  9. 一种功率变换器的功率控制方法，其特征在于，所述方法应用于所述功率变换器中的控制器，所述功率变换器还包括功率变换电路，所述控制器连接所述功率变换电路；所述方法包括：
    基于所述功率变换电路的输出电气量以及多段下垂滞环面得到所述功率变换电路的目标功率参考值；
    控制所述功率变换电路的输出功率值等于所述目标功率参考值。
  10. 根据权利要求9所述的方法，其特征在于，所述基于所述功率变换电路的输出电气量以及多段下垂滞环面得到所述功率变换电路的目标功率参考值包括：
    根据所述输出电气量以及多段下垂滞环面得到所述输出电气量对应的功率限值；
    在所述原功率参考值小于0时，得到所述目标功率参考值等于0；
    在所述原功率参考值大于或等于0且小于或等于功率限值时，得到所述目标功率参考值等于所述原功率参考值；
    在所述原功率参考值大于所述功率限值时，得到所述目标功率参考值等于所述功率限值。
  11. 根据权利要求10所述的方法，其特征在于，所述根据所述输出电气量以及多段下垂滞环面得到所述输出电气量对应的功率限值包括：
    在所述输出电气量大于或等于第一电气量阈值且小于第二电气量阈值时，获取所述输出电气量对应的功率限值为所述多段下垂滞环面中的滞环段曲线对应的值。
  12. 根据权利要求11所述的方法，其特征在于，所述方法还包括：
    在所述输出电气量大于或等于所述第二电气量阈值且小于第三电气量阈值时，获取所述输出电气量对应的功率限值为所述多段下垂滞环面中的第一段下垂曲线对应的值；
    在所述输出电气量大于或等于所述第三电气量阈值且小于第四电气量阈值时，获取所述输出电气量对应的功率限值为所述多段下垂滞环面中的第二段下垂曲线对应的值；
    当所述输出电气量大于或等于第N+1电气量阈值且小于第N+2电气量阈值时，获取所述输出电气量对应的功率限值为所述多段下垂滞环面中的第N段下垂曲线对应的值，N为大于或等于1的正整数。
  13. 根据权利要求12所述的方法，其特征在于，在所述输出电气量对应的功率限值为所述多段下垂滞环面中的N段下垂曲线对应的值时，第一时刻对应的功率限值小于或等于第二时刻对应的功率限值，所述第一时刻晚于所述第二时刻。
  14. 根据权利要求11-13任一所述的方法，其特征在于，所述方法还包括：
    在所述输出电气量小于所述第二电气量阈值的时间达到第一阈值时，根据预设时间将功率限值增大至为所述多段下垂滞环面中的滞环段曲线对应的值。
  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：
    在所述输出电气量大于或等于所述第二电气量阈值的次数超过第二阈值时，增大所述预设时间。
  16. 根据权利要求9-15任一所述的方法，其特征在于，所述目标功率参考值为目标有功功率参考值或者目标无功功率参考值。
  17. 一种供电***，其特征在于，所述供电***包括供电单元和如权利要求1-8任一项所述的功率变换器，所述供电单元连接所述功率变换器，所述功率变换器连接交流负载。
  18. 根据权利要求17所述的供电***，其特征在于，所述供电单元为光伏阵列，所述功率变换器为光伏功率变换器；或者，所述供电单元为风电发电机或者储能电池，所述功率变换器为储能功率变换器。
PCT/CN2023/118636 2022-09-29 2023-09-13 功率控制方法、功率变换器及供电*** WO2024067105A1 (zh)

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CN115528744A (zh) * 2022-09-29 2022-12-27 华为数字能源技术有限公司 功率控制方法、功率变换器及供电***

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104935002A (zh) * 2015-05-29 2015-09-23 国家电网公司 一种分布式光伏电源并网发电过电压调节方法
CN106300394A (zh) * 2016-11-04 2017-01-04 中国电力科学研究院 一种新能源电站的一次调频控制方法及***
US20200313565A1 (en) * 2019-03-29 2020-10-01 Rockwell Automation Technologies, Inc. Multi-segment and nonlinear droop control for parallel operating active front end power converters
CN112928746A (zh) * 2021-01-15 2021-06-08 西安交通大学 一种直流微网变流器的自适应分段下垂控制方法
CN113315166A (zh) * 2021-05-27 2021-08-27 国网河北省电力有限公司电力科学研究院 一种多虚拟同步机惯量配置方法、装置和终端设备
CN113410861A (zh) * 2020-03-17 2021-09-17 内蒙古电力(集团)有限责任公司内蒙古电力科学研究院分公司 一种适用于多端柔性直流***的下垂控制参数优化方法
CN115528744A (zh) * 2022-09-29 2022-12-27 华为数字能源技术有限公司 功率控制方法、功率变换器及供电***

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104935002A (zh) * 2015-05-29 2015-09-23 国家电网公司 一种分布式光伏电源并网发电过电压调节方法
CN106300394A (zh) * 2016-11-04 2017-01-04 中国电力科学研究院 一种新能源电站的一次调频控制方法及***
US20200313565A1 (en) * 2019-03-29 2020-10-01 Rockwell Automation Technologies, Inc. Multi-segment and nonlinear droop control for parallel operating active front end power converters
CN113410861A (zh) * 2020-03-17 2021-09-17 内蒙古电力(集团)有限责任公司内蒙古电力科学研究院分公司 一种适用于多端柔性直流***的下垂控制参数优化方法
CN112928746A (zh) * 2021-01-15 2021-06-08 西安交通大学 一种直流微网变流器的自适应分段下垂控制方法
CN113315166A (zh) * 2021-05-27 2021-08-27 国网河北省电力有限公司电力科学研究院 一种多虚拟同步机惯量配置方法、装置和终端设备
CN115528744A (zh) * 2022-09-29 2022-12-27 华为数字能源技术有限公司 功率控制方法、功率变换器及供电***

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