WO2020100372A1 - Electric power converting device, and method for controlling electric power converting device - Google Patents

Electric power converting device, and method for controlling electric power converting device Download PDF

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Publication number
WO2020100372A1
WO2020100372A1 PCT/JP2019/033059 JP2019033059W WO2020100372A1 WO 2020100372 A1 WO2020100372 A1 WO 2020100372A1 JP 2019033059 W JP2019033059 W JP 2019033059W WO 2020100372 A1 WO2020100372 A1 WO 2020100372A1
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Prior art keywords
power
output
generator
value
limit value
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PCT/JP2019/033059
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French (fr)
Japanese (ja)
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輝 菊池
智道 伊藤
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株式会社日立製作所
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P9/00—Arrangements for controlling electric generators for the purpose of obtaining a desired output
    • 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
    • Y02E10/70—Wind energy
    • Y02E10/76—Power conversion electric or electronic aspects

Definitions

  • the present invention relates to the configuration of a power conversion device and its control, and particularly to a technique effective when applied to a power conversion device for a wind power generation system that is connected to a power system.
  • a power conversion device that converts AC power generated by a wind power generator into DC power, converts the DC power into AC power with a commercial frequency, and supplies the power to a power grid is used.
  • the configuration is included.
  • Wind power generation affects the system voltage due to fluctuations in power generation due to fluctuations in wind speed.
  • power supply quality in the grid is required.
  • the wind power generation system is equipped with mechanical system parts such as a wind turbine blade that receives wind and a gear that is connected between the wind turbine blade and the generator to convert the rotation speed. Since mechanical parts such as these are subject to mechanical fluctuations such as torque fluctuations, their lifespan is shortened, so it is important to suppress such torque fluctuations in order to extend the life of the mechanical part. ..
  • Patent Document 1 discloses "a control method in which a resistance chopper circuit composed of a chopper and a resistor is provided in a DC portion and electric power is consumed in the resistance chopper circuit to suppress a sudden change in generator torque".
  • Japanese Patent Laid-Open No. 2004-242242 discloses that "the chopper energization time is changed and controlled for thermal protection according to the output power and rotation speed of the generator, the power consumption level of the chopper and the frequency of its FRT (running continuation function).
  • a power conversion device for wind power generation that enables continuous operation is disclosed.
  • Patent Document 1 described above, if power is consumed in the resistance chopper circuit in order to suppress a sudden change in the generator torque, the power from the wind is converted into heat and consumed. The power utilization rate will decrease. On the other hand, when power is not consumed by the resistance chopper circuit, the generator torque suddenly changes, which shortens the life of mechanical components of the wind turbine.
  • Patent Document 2 when the power characteristic value exceeds the safe power setting value, the power characteristic value of the portion that exceeds the safe power setting value is sent to the generator control system as a generated power suppression request command to limit the power (torque limit). Set to operation mode. Therefore, the utilization factor of wind power is reduced during the power limiting operation mode and during the period from the power limiting operating mode to the return to the steady operation mode.
  • an object of the present invention is to provide a highly efficient and reliable power converter for a wind power generation system that is connected to an electric power system, while suppressing a decrease in the utilization factor of wind power and suppressing a decrease in the life of a wind turbine machine system component.
  • An object is to provide a power converter for a high wind power generation system and a control method thereof.
  • the present invention provides a first power converter that converts variable frequency AC power output from a generator connected to a shaft of a wind turbine into DC power, and the DC power of commercial frequency.
  • a second power converter that converts the AC power to supply to a power system, and a DC power controller that is connected between the first power converter and the second power converter and controls the DC power
  • a control unit that controls the DC power controller based on the variable frequency AC power and the commercial frequency AC power, the control unit based on the variable frequency AC power.
  • Generator operating state detector for detecting the operating state of, the system output detector for detecting the system output of the power system based on the AC power of the commercial frequency, the output of the generator operating state detector, and the Based on the output of the system output detector, a generator output limit value calculator that calculates the output limit value of the generator, the output of the generator output limit value calculator, and based on the output of the system output detector, A power command calculator for calculating a power command to the DC power controller, and based on a power command from the power command calculator, the output of the generator falls within the range of the output limit value.
  • the DC power controller controls the DC power.
  • the present invention is a method for controlling a power converter for a wind power generation system that is connected to an electric power system, wherein the operating state of the generator is detected based on variable frequency AC power output from the generator.
  • An output of the generator based on the detected operating state of the generator and a detected system output to the power system based on the commercial frequency AC power supplied to the power system.
  • a feature is that a power command value for controlling power is calculated, and the DC power is controlled based on the calculated power command value.
  • a highly efficient and highly reliable wind power system that can suppress a reduction in the utilization factor of wind power and a lifespan of a wind turbine machine system component can be suppressed.
  • a power converter for a power generation system and a control method thereof can be realized.
  • FIG. 3 is a diagram showing an example of operation waveforms of the power conversion device according to the first embodiment. It is a figure which shows the structure of the power converter device which concerns on Example 2 of this invention. It is a figure which shows the structure of the charging electric power command calculator in FIG.
  • FIG. 7 is a diagram showing an example of operation waveforms of the power conversion device according to the second embodiment.
  • FIG. 1 is a diagram showing the configuration of the power converter of the present embodiment.
  • the power converter 1 of the present embodiment has, as its main components, a power converter 2, a power converter 3, a power consumer 4, a voltage detector 5, a current detector 6, a voltage detector 7, a current detector 8, It has a control unit 9.
  • the three-phase AC part of the power converter 2 is connected to the three-phase AC terminal of the generator 10.
  • the DC parts of the power converter 2 and the power converter 3 are connected to each other, and the power consumer 4 is connected to the DC part.
  • the three-phase AC part of the power converter 3 is connected to the power system 12.
  • the rotor of the generator 10 is connected to the wind turbine blade 11, and when the rotor of the generator 10 rotates by rotating the wind turbine blade 11 with the power (wind force) received from the wind, the generator 10 has a frequency corresponding to the rotation speed. Outputs three-phase AC power.
  • the power converter 2 converts the three-phase AC power output from the generator 10 into DC power and outputs the DC power to the DC unit.
  • the power converter 3 converts the DC power output from the power converter 2 to the DC unit into three-phase AC power having a commercial frequency, and supplies the power system 12 with the three-phase AC power.
  • the power consumer 4 consumes power from the DC parts of the power converter 2 and the power converter 3 according to the power consumption command.
  • the power consumption device 4 is composed of, for example, a resistance chopper circuit in which a resistance and a chopper are combined, but may have another structure. Further, a gear (speed increaser) that converts the rotation speed may be connected between the generator 10 and the wind turbine blade 11.
  • the voltage detector 5 is connected to the three-phase AC side of the power converter 2 and detects the terminal voltage of the generator 10.
  • the current detector 6 is connected to the three-phase AC side of the power converter 2 and detects the terminal current flowing from the generator 10 to the power converter 2.
  • the voltage detector 7 is connected to the three-phase AC side of the power converter 3 and detects the system voltage of the power system 12.
  • the current detector 8 is connected to the three-phase AC side of the power converter 3 and detects the system current flowing from the power converter 3 to the power system 12.
  • the control unit 9 detects the terminal voltage detection value output by the voltage detector 5, the terminal current detection value output by the current detector 6, the system voltage detection value output by the voltage detector 7, and the system current detection output by the current detector 8. The value is input, and the power consumption command to the power consumer 4 is output.
  • the control unit 9 includes a system output detector 13, a generator operating state detector 14, a generator output limit value calculator 15, and a power consumption command calculator 16.
  • the system output detector 13 receives the system voltage detection value output by the voltage detector 7 and the system current detection value output by the current detector 8 as input, and detects the system output which is the power output by the power converter 3 to the power system 12. The value is output to the generator output limit value calculator 15.
  • the generator operating state detector 14 receives the detected terminal voltage value output from the voltage detector 5 and the detected terminal current value output from the current detector 6 as input, and outputs the detected generator speed value indicating the rotation speed of the generator 10, The generator output detection value representing the electric power output from the machine 10 is output to the generator output limit value calculator 15.
  • the generator output limit value calculator 15 receives the system output detection value output by the system output detector 13, the generator speed detection value and the generator output detection value output by the generator operating state detector 14, and inputs the generator output limit value.
  • the output upper limit value and the output lower limit value are output to the power consumption command calculator 16.
  • the generator output limit value calculator 15 calculates the output upper limit value and the output lower limit value of the generator 10 based on the generator speed detection value and the generator output detection value from the generator operating state detector 14.
  • the power consumption command calculator 16 inputs the output upper limit value and the output lower limit value output from the generator output limit value calculator 15 and the system output detection value output from the system output detector 13 to the power consumption command for the power consumer 4. Is output.
  • FIG. 2 shows the configuration of the generator output limit value calculator 15 in FIG.
  • the generator output limit value calculator 15 has a database 151, a change rate limiter 152, an adder 153, and a subtractor 154.
  • the database 151 receives the generator speed detection value and the generator output detection value as input, and sets the change width setting value and the change rate setting of the change width and the change rate of the generator output permitted by the wind turbine mechanical system such as the wind turbine blade 11 and the gear, respectively. Output as a value.
  • the rate-of-change limiter 152 inputs the rate-of-change setting value and the system output detection value output from the database 151, and performs the rate-of-change limiter processing on the system output detection value so that the output of the rate-of-change limiter 152 becomes equal to or less than the rate-of-change setting value Then, it is output as the generator output reference value.
  • the adder 153 inputs the generator output reference value output by the change rate limiter 152 and the change width set value output by the database 151, and outputs the sum thereof as the output upper limit value of the generator.
  • the subtractor 154 inputs the generator output reference value output by the change rate limiter 152 and the change width set value output by the database 151, and outputs the difference between them as the output lower limit value of the generator.
  • the generator output limit value calculator 15 includes a database 151 that stores the change width setting value and the change rate setting value corresponding to the generator speed detection value and the generator output detection value, and has a predetermined change width setting.
  • the output upper limit value and the output lower limit value of the generator 10 are changed based on the value and the predetermined change rate set value.
  • the change width set value and the change rate set value change according to the operating state of the generator 10.
  • FIG. 3 shows the configuration of the power consumption command calculator 16 in FIG.
  • the power consumption command calculator 16 has an upper / lower limit limiter 161, a subtractor 162, and a lower limit limiter 163.
  • the upper and lower limiter 161 receives the system output detection value, the output upper limit value, and the output lower limit value as input, performs limiter processing on the system output detection value so that the value falls between the output upper limit value and the output lower limit value, and the generator output Output as an output command.
  • the subtractor 162 receives the generator output command output from the upper and lower limit limiter 161 and the system output detection value as input, calculates the difference between them, and outputs the difference to the lower limit limiter 163.
  • the lower limit limiter 163 receives the output of the subtractor 162 as input and performs limiter processing with a lower limit of zero to prevent the power consumption command from becoming a negative value and outputs it as a power consumption command.
  • the generator output command matches the system output detection value, and the power consumption command is zero. If the circuit loss of the power conversion device 1 is neglected as a minute amount, the generator output matches the system output.
  • the power consumption command is given by the difference between the output lower limit value and the system output detection value, and the power consumption of that value is calculated by the power consumer 4. Will be consumed. Since the generator output is almost equal to the sum of the power consumed by the power consumer 4 and the system output, the generator output matches the output lower limit value. That is, the power consumer 4 consumes power so that the generator output does not fall below the output lower limit even if the system output drops below the output lower limit of the upper and lower limiter 161.
  • the generator output matches the system output. Therefore, when the system output rises to the output upper limit value of the upper and lower limiter 161, the generator output also rises to the output upper limit value or more.
  • an element for generating power is required in addition to the generator 10. However, in the present embodiment, there is no such element, so the increase in the generator output cannot be suppressed.
  • the generator output operates so as not to be less than or equal to the output lower limit value, and it is possible to suppress a decrease in the generator output.
  • the system output detection value is equal to or higher than the output upper limit value of the upper and lower limiter 161
  • the configuration will be described.
  • FIG. 4 shows an example of the characteristics of the change width set value and the change rate set value output from the database 151 in FIG.
  • the change width set value and the change rate set value are made small. Since the torque output from the generator is large in this region, it is possible to suppress the torque fluctuation given to the mechanical system parts of the wind turbine within a predetermined range by providing such characteristics, and the mechanical system parts of the wind turbine It is possible to extend the life of the.
  • the torque output from the generator 10 is changed within a range that the mechanical system parts of the wind turbine can tolerate by making the change width set value relatively large.
  • the power consumed by the power consumption device 4 is reduced, and it is possible to suppress a reduction in the utilization rate of power from the wind.
  • the change rate set value and the change rate are changed in the operating region where the torque fluctuation applied to the mechanical system components of the wind turbine is severe.
  • the width setting value small, the torque fluctuation of the generator is suppressed, and in the operating region where the torque fluctuation is not severe, by setting the change rate setting value and the change width setting value large, the power from the wind is used.
  • the rate decrease can be suppressed.
  • the characteristics output from the database 151 are not limited to the characteristics shown in FIG. 4, and other characteristics may be used.
  • FIG. 5 shows an example of operation waveforms of the power conversion device of this embodiment.
  • the system output detection value is P0 until time T1. Due to the configuration of the generator output limit value calculator 15, the generator output reference value is P0 in the steady state.
  • the output upper limit value is a value obtained by adding the change width setting value ⁇ P to the generator output reference value, and the output lower limit value is a value obtained by subtracting the change width setting value ⁇ P from the generator output reference value. Further, since the system output detection value is P0, the generator output command is also P0 due to the configuration of the power consumption command calculator 16.
  • the power consumption command obtained by subtracting the system output detection value from the generator output command is zero, so the power consumed by the power consumer 4 is zero. If the circuit loss of the power converter 1 is neglected as a minute amount, when the power consumed by the power consumer 4 is zero, the generator output and the system output match, so the generator output becomes P0.
  • a grid fault occurs and the grid voltage temporarily becomes zero. Since the system voltage is zero, power cannot be supplied from the power converter 3 to the power system 12, so the system output detection value becomes zero. Since the system output detection value becomes zero, the generator output command matches the output lower limit value P0- ⁇ P of the upper / lower limit limiter 161, and the power consumption command obtained by subtracting the system output detection value from the generator output command is P0. -It becomes ⁇ P. When the power consumer 4 consumes P0- ⁇ P power according to the power consumption command, the generator output becomes P0- ⁇ P because the system output detection value is zero.
  • the generator output reference value decreases according to the change rate setting value, and the output upper limit value and output lower limit value also decrease.
  • the generator output command decreases in accordance with the output lower limit value. Therefore, the power consumption command obtained by subtracting the system output detection value from the generator output command also decreases.
  • the generator output also decreases because the system output detection value is zero.
  • the generator output command rises to the smaller one of the output upper limit value and the value of P0, but in this embodiment, the output upper limit value ⁇ P0 It is assumed that the command rises to the output upper limit value.
  • the value obtained by subtracting the system output detection value from the generator output command becomes a negative value, but the power consumption command becomes zero due to the action of the lower limit limiter 163, and the power consumed by the power consumer 4 becomes zero.
  • the generator output and the system output match, so the generator output is P0.
  • the system output detection value is near P0, so the generator output reference value increases according to the change rate setting value, and the output upper limit value and output lower limit value also increase.
  • the generator output command increases in accordance with the output upper limit value, but since the value obtained by subtracting the system output detection value from the generator output command maintains a negative value, the lower limit limiter 163 acts to reduce the power consumption command. It becomes zero, and the power consumed by the power consumer 4 becomes zero. When the power consumed by the power consumer 4 is zero, the generator output and the system output match, so the generator output matches the system output detection value.
  • the generator output command will match the system output detection value. Since the value obtained by subtracting the system output detection value from the generator output command is zero, the power consumption command becomes zero, and the power consumed by the power consumer 4 becomes zero. When the power consumed by the power consumer 4 is zero, the generator output and the system output match, so the generator output matches the system output detection value. That is, the output upper limit value and the output lower limit value change while maintaining the predetermined difference value ( ⁇ P). Further, the difference value ( ⁇ P) changes according to the operating state of the generator 10.
  • the power converter 1 of the present embodiment is the first power converter (power converter) that converts the variable frequency AC power output from the generator 10 connected to the shaft of the wind turbine into DC power. 2), a second power converter (power converter 3) that converts DC power into AC power of commercial frequency and supplies the power to the power grid 12, a first power converter (power converter 2), and a second power converter (power converter 2).
  • DC power controller connected between two power converters (power converter 3) and controlling DC power (power consumer 4), and DC power based on variable frequency AC power and commercial frequency AC power.
  • a control unit 9 for controlling the controller (power consumption device 4), and the control unit 9 detects the operating state of the generator 10 based on the alternating-current power of a variable frequency;
  • the output of the generator 10 based on the output of the grid output detector 13 that detects the grid output of the grid 12 based on the commercial frequency AC power, the output of the generator operating state detector 14, and the output of the grid output detector 13.
  • a power command to the DC power controller (power consumer 4)
  • a power command calculator (power consumption command calculator 16) for calculating the output of the generator 10 based on the power command (power consumption command) from the power command calculator (power consumption command calculator 16).
  • the DC power is controlled by the DC power controller (power consumer 4) so that the power consumption value is within the range of the output limit value.
  • the power consumption by the power consumption unit 4 suppresses the decrease in the generator output as compared with the system output. It As a result, it is possible to mitigate the fluctuation of torque applied to the wind turbine mechanical system such as the wind turbine blade 11 and the gear, and to extend the life of the wind turbine mechanical system.
  • the power consumption command becomes large, and when the change width set value is set large, the power consumption command becomes small.
  • the change rate set value output from the database 151 is set small, the power consumption command becomes large, and when the change rate set value is set large, the power consumption command becomes small. That is, the power consumed by the power consuming device 4 can be adjusted by adjusting the change width setting value and the change rate setting value.
  • FIG. 6 is a diagram showing the configuration of the power conversion device according to the present embodiment.
  • the power converter 17 of this embodiment has, as its main components, a power converter 2, a power converter 3, a power storage device 18, a voltage detector 5, a current detector 6, a voltage detector 7, a current detector 8, and control. It has a section 19.
  • the difference from the power conversion device 1 of the first embodiment is that a power storage device 18 is provided instead of the power consumption device 4, and a charging power command computing device 20 is provided instead of the power consumption command computing device 16. is there.
  • a power storage device 18 is provided instead of the power consumption device 4
  • a charging power command computing device 20 is provided instead of the power consumption command computing device 16.
  • the power storage device 18 charges electric power from the DC parts of the power converter 2 and the power converter 3 in response to the charging power command from the charging power command calculator 20, or charges the DC parts of the power converter 2 and the power converter 3 to each other. Discharge electricity.
  • the charging power command calculator 20 receives the output upper limit value and the output lower limit value output from the generator output limit value calculator 15, and the system output detection value output from the system output detector 13 as an input, and issues a charging power command to the power storage device 18. Output.
  • FIG. 7 shows the configuration of the charging power command calculator 20 in FIG.
  • the charging power command calculator 20 has an upper and lower limit limiter 201 and a subtractor 202.
  • the upper / lower limit limiter 201 receives the system output detection value, the output upper limit value, and the output lower limit value as input, performs limiter processing on the system output detection value so that the value falls between the output upper limit value and the output lower limit value, and the generator output. Output as an output command.
  • the subtracter 202 receives the generator output command output by the upper and lower limit limiter 201 and the system output detection value, calculates the difference between them, and outputs the charging power command.
  • the charging power command has a positive value, it represents a charging power command, and when it has a negative value, it represents a discharging power command.
  • the generator output command matches the system output detection value, the charging power command becomes zero, and the power charged / discharged by the power storage device 18 becomes zero.
  • the generator output and the system output match.
  • the charging power command becomes a positive value given by the difference between the output lower limit value and the system output detection value, and the power storage device 18 has that value. Will be charged with electricity. Since the generator output is substantially equal to the sum of the electric power charged in the power storage device 18 and the system output, the generator output matches the output lower limit value.
  • the power storage device 18 charges electric power so that the generator output does not fall below the output lower limit even if the system output falls below the output lower limit of the upper / lower limit limiter 201.
  • the charging power command becomes a negative value given by the difference between the output upper limit value and the system output detection value, and the power storage device 18 has that value.
  • the amount of electric power will be discharged. Since the generator output is substantially equal to the difference between the system output and the electric power discharged from the power storage device 18, the generator output matches the output upper limit value.
  • the power storage device 18 discharges electric power so that the generator output does not exceed the output upper limit value even if the system output rises above the output upper limit value of the upper and lower limiter 201.
  • the power storage device 18 when the system output detection value is less than or equal to the output lower limit value of the upper and lower limit limiter 201, the power storage device 18 is charged to operate so that the generator output does not fall below the output lower limit value, and the system output detection value When the output exceeds the output upper limit of the upper / lower limit limiter 201, the power storage device 18 discharges to operate so that the generator output does not exceed the output upper limit. By such an operation, it is possible to suppress a decrease or an increase in the generator output.
  • FIG. 8 shows an example of operation waveforms of the power conversion device of this embodiment.
  • the system output detection value is P0 until time T1.
  • the generator output reference value is P0 in the steady state.
  • the output upper limit value is a value obtained by adding the change width setting value ⁇ P to the generator output reference value
  • the output lower limit value is a value obtained by subtracting the change width setting value ⁇ P from the generator output reference value.
  • the generator output command is also P0 due to the configuration of the charging power command calculator 20.
  • the charging power command obtained by subtracting the system output detection value from the generator output command becomes zero, so the power charged in the power storage device 18 becomes zero. If the circuit loss or the like of the power conversion device 17 is neglected as a minute amount, when the electric power charged in the power storage device 18 is zero, the generator output and the system output match, so the generator output becomes P0.
  • a grid fault occurs and the grid voltage temporarily becomes zero. Since the system voltage is zero, power cannot be supplied from the power converter 3 to the power system 12, so the system output detection value becomes zero. Since the system output detection value becomes zero, the generator output command matches the output lower limit value P0- ⁇ P of the upper / lower limit limiter 201, and the charging power command obtained by subtracting the system output detection value from the generator output command is P0. -It becomes ⁇ P. When the power storage device 18 charges the power of P0- ⁇ P according to the charging power command, the generator output becomes P0- ⁇ P because the system output detection value is zero.
  • the generator output reference value decreases according to the change rate setting value, and the output upper limit value and output lower limit value also decrease.
  • the generator output command decreases in accordance with the output lower limit value. Therefore, the charging power command obtained by subtracting the system output detection value from the generator output command also decreases.
  • the system output detection value is zero, so the generator output also decreases.
  • the generator output command rises to the smaller one of the output upper limit value and the value of P0, but in this embodiment, the output upper limit value ⁇ P0 It is assumed that the command rises to the output upper limit value.
  • the value obtained by subtracting the system output detection value from the generator output command becomes a negative value, and the charging power command becomes a negative value, so it becomes a discharge command.
  • the power output from the power storage device 18 causes the generator output to match the output upper limit value.
  • the system output detection value is near P0, so the generator output reference value increases according to the change rate setting value, and the output upper limit value and output lower limit value also increase.
  • the generator output command increases in accordance with the output upper limit value, but the power output from the power storage device 18 causes the generator output to match the output upper limit value.
  • the generator output command will match the system output detection value. Since the value obtained by subtracting the system output detection value from the generator output command is zero, the charging power command is zero, and the power charged and discharged in the power storage device 18 is zero. When the electric power charged and discharged in the power storage device 18 is zero, the generator output and the system output match, so the generator output matches the system output detection value.
  • the power storage device 18 charges the power, so that the decrease in the generator output is suppressed as compared with the system output. ..
  • the power storage device 18 discharges electric power, so that the increase in the generator output is suppressed as compared with the system output.
  • the present invention is not limited to the above-described embodiments, but includes various modifications.
  • the above-described embodiments have been described in detail in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the configurations described.
  • a part of the configuration of a certain embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of a certain embodiment.
  • other configurations can be added / deleted / replaced.

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  • Power Engineering (AREA)
  • Control Of Eletrric Generators (AREA)
  • Supply And Distribution Of Alternating Current (AREA)

Abstract

Provided are an electricity generating system for a wind power electricity generating system connected to an electric power grid, and a method for controlling the same, wherein the electric power converting device for the wind power electricity generating system is capable of limiting a deterioration in the service life of components of a wind turbine mechanical system while limiting a deterioration in the wind power utilization rate, and has a high efficiency and high reliability.　This electricity generating system for a wind power electricity generating system is characterized by being provided with: a first electric power converter for converting variable frequency alternating-current power output by an electricity generator connected to a shaft of a wind turbine into direct-current power; a second electric power converter for converting the direct-current power into commercial frequency alternating-current power and supplying the same to the electric power grid; a direct-current power controller which is connected between the first electric power converter and the second electric power converter, and which controls the direct-current power; and a control unit which controls the direct-current power controller on the basis of the variable frequency alternating-current power and the commercial frequency alternating-current power.

Description

電力変換装置、電力変換装置の制御方法Power converter and power converter control method
　本発明は、電力変換装置の構成とその制御に係り、特に、電力系統に連系する風力発電システム向け電力変換装置に適用して有効な技術に関する。 The present invention relates to the configuration of a power conversion device and its control, and particularly to a technique effective when applied to a power conversion device for a wind power generation system that is connected to a power system.
　近年、風力発電システムの電力系統への導入が進んでいる。風力発電システムの一例として、風力用発電機で発電された交流電力を直流電力へ変換し、その直流電力を商用周波数の交流電力へ変換して電力系統に電力を供給する電力変換装置を用いた構成が挙げられる。 In recent years, the introduction of wind power generation systems into the electric power system is progressing. As an example of a wind power generation system, a power conversion device that converts AC power generated by a wind power generator into DC power, converts the DC power into AC power with a commercial frequency, and supplies the power to a power grid is used. The configuration is included.
　風力発電は、風速の変動による発電変動があるため系統電圧に影響を与える。風力発電を大量に導入するために、系統における電源品質が要求される。 ∙ Wind power generation affects the system voltage due to fluctuations in power generation due to fluctuations in wind speed. In order to introduce a large amount of wind power generation, power supply quality in the grid is required.
　一方、風力発電システムは、風を受ける風車ブレードや風車ブレードと発電機の間に接続されて回転数を変換するギアなどの機械系部品を備えている。このような機械系部品はトルク変動のような機械的変動を受けることで寿命が低下するため、機械系部品の長寿命化を図るためにはそのようなトルク変動を抑制することが重要である。 On the other hand, the wind power generation system is equipped with mechanical system parts such as a wind turbine blade that receives wind and a gear that is connected between the wind turbine blade and the generator to convert the rotation speed. Since mechanical parts such as these are subject to mechanical fluctuations such as torque fluctuations, their lifespan is shortened, so it is important to suppress such torque fluctuations in order to extend the life of the mechanical part. ..
　本技術分野の背景技術として、例えば、特許文献１のような技術がある。特許文献１には「チョッパと抵抗器で構成される抵抗チョッパ回路を直流部に設け、抵抗チョッパ回路で電力を消費することで発電機トルクの急変を抑制する制御方法」が開示されている。 As a background art in this technical field, there is a technology as disclosed in Patent Document 1, for example. Patent Document 1 discloses "a control method in which a resistance chopper circuit composed of a chopper and a resistor is provided in a DC portion and electric power is consumed in the resistance chopper circuit to suppress a sudden change in generator torque".
　また、特許文献２には「発電機の出力電力と回転数、チョッパの電力消費レベルとそのＦＲＴ（運転継続機能）の頻度に応じて、熱保護のためにチョッパの通電時間を変更制御して運転継続を可能にする風力発電用電力変換装置」が開示されている。 Further, Japanese Patent Laid-Open No. 2004-242242 discloses that "the chopper energization time is changed and controlled for thermal protection according to the output power and rotation speed of the generator, the power consumption level of the chopper and the frequency of its FRT (running continuation function). A power conversion device for wind power generation that enables continuous operation is disclosed.
米国特許第８９８１５８４号明細書US Pat. No. 8,981,584 特開２０１２－２３１６２４号公報JP 2012-231624 A
　しかし、上記特許文献１では、発電機トルクの急変を抑制するために、抵抗チョッパ回路で電力を消費すると、風からのパワーを熱に変換して消費していることになるため、風からのパワーの利用率が低下することになる。一方で、抵抗チョッパ回路で電力を消費しない場合は発電機トルクが急変することで、風車の機械系部品の寿命が低下する。 However, in Patent Document 1 described above, if power is consumed in the resistance chopper circuit in order to suppress a sudden change in the generator torque, the power from the wind is converted into heat and consumed. The power utilization rate will decrease. On the other hand, when power is not consumed by the resistance chopper circuit, the generator torque suddenly changes, which shortens the life of mechanical components of the wind turbine.
　また、上記特許文献２では、電力特性値が安全電力設定値を超えた場合はその超えた部分の電力特性値を発電機制御システムに発電電力抑制要求指令として送出して電力制限（トルク制限）運転モードにする。そのため、電力制限運転モード時および電力制限運転モードから定常運転モードへ復帰するまでの間、風力の利用率が低下する。 Further, in Patent Document 2, when the power characteristic value exceeds the safe power setting value, the power characteristic value of the portion that exceeds the safe power setting value is sent to the generator control system as a generated power suppression request command to limit the power (torque limit). Set to operation mode. Therefore, the utilization factor of wind power is reduced during the power limiting operation mode and during the period from the power limiting operating mode to the return to the steady operation mode.
　そこで、本発明の目的は、電力系統に連系する風力発電システム向け電力変換装置において、風力の利用率低下を抑制しつつ、風車機械系部品の寿命低下を抑制可能な高効率で信頼性の高い風力発電システム向け電力変換装置とその制御方法を提供することにある。 Therefore, an object of the present invention is to provide a highly efficient and reliable power converter for a wind power generation system that is connected to an electric power system, while suppressing a decrease in the utilization factor of wind power and suppressing a decrease in the life of a wind turbine machine system component. An object is to provide a power converter for a high wind power generation system and a control method thereof.
　上記課題を解決するために、本発明は、風車の軸に接続された発電機の出力する可変周波数の交流電力を直流電力に変換する第１の電力変換器と、前記直流電力を商用周波数の交流電力に変換して電力系統に供給する第２の電力変換器と、前記第１の電力変換器と前記第２の電力変換器の間に接続され、前記直流電力を制御する直流電力制御器と、前記可変周波数の交流電力および前記商用周波数の交流電力に基づき、前記直流電力制御器を制御する制御部と、を備え、前記制御部は、前記可変周波数の交流電力に基づき、前記発電機の運転状態を検出する発電機運転状態検出器と、前記商用周波数の交流電力に基づき、前記電力系統の系統出力を検出する系統出力検出器と、前記発電機運転状態検出器の出力、および前記系統出力検出器の出力に基づき、前記発電機の出力制限値を演算する発電機出力制限値演算器と、前記発電機出力制限値演算器の出力、および前記系統出力検出器の出力に基づき、前記直流電力制御器に対する電力指令を演算する電力指令演算器と、を有し、前記電力指令演算器からの電力指令に基づき、前記発電機の出力が前記出力制限値の範囲内に収まるように、前記直流電力制御器により前記直流電力を制御することを特徴とする。 In order to solve the above problems, the present invention provides a first power converter that converts variable frequency AC power output from a generator connected to a shaft of a wind turbine into DC power, and the DC power of commercial frequency. A second power converter that converts the AC power to supply to a power system, and a DC power controller that is connected between the first power converter and the second power converter and controls the DC power And a control unit that controls the DC power controller based on the variable frequency AC power and the commercial frequency AC power, the control unit based on the variable frequency AC power. Generator operating state detector for detecting the operating state of, the system output detector for detecting the system output of the power system based on the AC power of the commercial frequency, the output of the generator operating state detector, and the Based on the output of the system output detector, a generator output limit value calculator that calculates the output limit value of the generator, the output of the generator output limit value calculator, and based on the output of the system output detector, A power command calculator for calculating a power command to the DC power controller, and based on a power command from the power command calculator, the output of the generator falls within the range of the output limit value. The DC power controller controls the DC power.
　また、本発明は、電力系統に連系される風力発電システム向け電力変換装置の制御方法であって、発電機から出力される可変周波数の交流電力に基づき、前記発電機の運転状態を検出し、前記電力系統へ供給される商用周波数の交流電力に基づき、前記電力系統への系統出力を検出し、前記検出した発電機の運転状態、および前記検出した系統出力に基づき、前記発電機の出力制限値を算出し、前記算出した出力制限値、および前記検出した系統出力に基づき、前記発電機から出力される可変周波数の交流電力と前記電力系統へ供給される商用周波数の交流電力間の直流電力を制御する電力指令値を算出し、当該算出した電力指令値に基づき、前記直流電力を制御することを特徴とする。 Further, the present invention is a method for controlling a power converter for a wind power generation system that is connected to an electric power system, wherein the operating state of the generator is detected based on variable frequency AC power output from the generator. An output of the generator based on the detected operating state of the generator and a detected system output to the power system based on the commercial frequency AC power supplied to the power system. A DC value between the variable frequency AC power output from the generator and the commercial frequency AC power supplied to the power system based on the calculated output limit value and the detected system output A feature is that a power command value for controlling power is calculated, and the DC power is controlled based on the calculated power command value.
　本発明によれば、電力系統に連系する風力発電システム向け電力変換装置において、風力の利用率低下を抑制しつつ、風車機械系部品の寿命低下を抑制可能な高効率で信頼性の高い風力発電システム向け電力変換装置とその制御方法を実現することができる。 According to the present invention, in a power conversion device for a wind power generation system that is connected to a power system, a highly efficient and highly reliable wind power system that can suppress a reduction in the utilization factor of wind power and a lifespan of a wind turbine machine system component can be suppressed. A power converter for a power generation system and a control method thereof can be realized.
　上記した以外の課題、構成及び効果は、以下の実施形態の説明により明らかにされる。 The problems, configurations, and effects other than those described above will be clarified by the following description of the embodiments.
本発明の実施例１に係る電力変換装置の構成を示す図である。It is a figure which shows the structure of the power converter device which concerns on Example 1 of this invention. 図１における発電機出力制限値演算器の構成を示す図である。It is a figure which shows the structure of the generator output limit value calculator in FIG. 図１における消費電力指令演算器の構成を示す図である。It is a figure which shows the structure of the power consumption command calculator in FIG. 図２におけるデータベースの出力特性の一例を示す図である。It is a figure which shows an example of the output characteristic of the database in FIG. 実施例１に係る電力変換装置の動作波形の一例を示す図である。FIG. 3 is a diagram showing an example of operation waveforms of the power conversion device according to the first embodiment. 本発明の実施例２に係る電力変換装置の構成を示す図である。It is a figure which shows the structure of the power converter device which concerns on Example 2 of this invention. 図６における充電電力指令演算器の構成を示す図である。It is a figure which shows the structure of the charging electric power command calculator in FIG. 実施例２に係る電力変換装置の動作波形の一例を示す図である。FIG. 7 is a diagram showing an example of operation waveforms of the power conversion device according to the second embodiment.
　以下、図面を用いて本発明の実施例を説明する。なお、各図面において同一の構成については同一の符号を付し、重複する部分についてはその詳細な説明は省略する。 An embodiment of the present invention will be described below with reference to the drawings. In each drawing, the same components are designated by the same reference numerals, and detailed description of overlapping portions will be omitted.
　図１から図５を参照して、本発明の実施例１の電力変換装置とその制御方法について説明する。図１は、本実施例の電力変換装置の構成を示す図である。本実施例の電力変換装置１は、主要な構成として、電力変換器２、電力変換器３、電力消費器４、電圧検出器５、電流検出器６、電圧検出器７、電流検出器８、制御部９を有している。 First Embodiment A power conversion device and a control method thereof according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 5. FIG. 1 is a diagram showing the configuration of the power converter of the present embodiment. The power converter 1 of the present embodiment has, as its main components, a power converter 2, a power converter 3, a power consumer 4, a voltage detector 5, a current detector 6, a voltage detector 7, a current detector 8, It has a control unit 9.
　電力変換器２の三相交流部は発電機１０の三相交流端子に接続している。電力変換器２と電力変換器３の直流部は互いに接続し、その直流部には電力消費器４が接続している。電力変換器３の三相交流部は電力系統１２に接続している。発電機１０の回転子は風車ブレード１１に接続し、風車ブレード１１が風から受けるパワー（風力）で回転することで発電機１０の回転子が回転すると、発電機１０は回転数に応じた周波数の三相交流電力を出力する。電力変換器２は発電機１０の出力する三相交流電力を直流電力に変換し、直流部へ出力する。 The three-phase AC part of the power converter 2 is connected to the three-phase AC terminal of the generator 10. The DC parts of the power converter 2 and the power converter 3 are connected to each other, and the power consumer 4 is connected to the DC part. The three-phase AC part of the power converter 3 is connected to the power system 12. The rotor of the generator 10 is connected to the wind turbine blade 11, and when the rotor of the generator 10 rotates by rotating the wind turbine blade 11 with the power (wind force) received from the wind, the generator 10 has a frequency corresponding to the rotation speed. Outputs three-phase AC power. The power converter 2 converts the three-phase AC power output from the generator 10 into DC power and outputs the DC power to the DC unit.
　電力変換器３は電力変換器２が直流部に出力する直流電力を商用周波数の三相交流電力に変換し、電力系統１２に三相交流電力を供給する。電力消費器４は消費電力指令に応じて電力変換器２と電力変換器３の直流部から電力を消費する。電力消費器４は例えば抵抗とチョッパを組み合わせた抵抗チョッパ回路などで構成されるが、その他の構成であっても良い。また、発電機１０と風車ブレード１１の間に回転数を変換するギア（増速機）が接続されていても良い。 The power converter 3 converts the DC power output from the power converter 2 to the DC unit into three-phase AC power having a commercial frequency, and supplies the power system 12 with the three-phase AC power. The power consumer 4 consumes power from the DC parts of the power converter 2 and the power converter 3 according to the power consumption command. The power consumption device 4 is composed of, for example, a resistance chopper circuit in which a resistance and a chopper are combined, but may have another structure. Further, a gear (speed increaser) that converts the rotation speed may be connected between the generator 10 and the wind turbine blade 11.
　電圧検出器５は電力変換器２の三相交流側に接続し、発電機１０の端子電圧を検出する。電流検出器６は電力変換器２の三相交流側に接続し、発電機１０から電力変換器２へ流れる端子電流を検出する。電圧検出器７は電力変換器３の三相交流側に接続し、電力系統１２の系統電圧を検出する。電流検出器８は電力変換器３の三相交流側に接続し、電力変換器３から電力系統１２へ流れる系統電流を検出する。 -The voltage detector 5 is connected to the three-phase AC side of the power converter 2 and detects the terminal voltage of the generator 10. The current detector 6 is connected to the three-phase AC side of the power converter 2 and detects the terminal current flowing from the generator 10 to the power converter 2. The voltage detector 7 is connected to the three-phase AC side of the power converter 3 and detects the system voltage of the power system 12. The current detector 8 is connected to the three-phase AC side of the power converter 3 and detects the system current flowing from the power converter 3 to the power system 12.
　制御部９は電圧検出器５の出力する端子電圧検出値、電流検出器６の出力する端子電流検出値、電圧検出器７の出力する系統電圧検出値、電流検出器８の出力する系統電流検出値を入力として、電力消費器４への消費電力指令を出力する。制御部９は、系統出力検出器１３、発電機運転状態検出器１４、発電機出力制限値演算器１５、消費電力指令演算器１６を有している。 The control unit 9 detects the terminal voltage detection value output by the voltage detector 5, the terminal current detection value output by the current detector 6, the system voltage detection value output by the voltage detector 7, and the system current detection output by the current detector 8. The value is input, and the power consumption command to the power consumer 4 is output. The control unit 9 includes a system output detector 13, a generator operating state detector 14, a generator output limit value calculator 15, and a power consumption command calculator 16.
　系統出力検出器１３は電圧検出器７の出力する系統電圧検出値、電流検出器８の出力する系統電流検出値を入力として、電力変換器３が電力系統１２へ出力する電力である系統出力検出値を発電機出力制限値演算器１５へ出力する。 The system output detector 13 receives the system voltage detection value output by the voltage detector 7 and the system current detection value output by the current detector 8 as input, and detects the system output which is the power output by the power converter 3 to the power system 12. The value is output to the generator output limit value calculator 15.
　発電機運転状態検出器１４は電圧検出器５の出力する端子電圧検出値、電流検出器６の出力する端子電流検出値を入力として、発電機１０の回転数を表す発電機速度検出値、発電機１０の出力する電力を表す発電機出力検出値を発電機出力制限値演算器１５へ出力する。 The generator operating state detector 14 receives the detected terminal voltage value output from the voltage detector 5 and the detected terminal current value output from the current detector 6 as input, and outputs the detected generator speed value indicating the rotation speed of the generator 10, The generator output detection value representing the electric power output from the machine 10 is output to the generator output limit value calculator 15.
　発電機出力制限値演算器１５は系統出力検出器１３の出力する系統出力検出値、発電機運転状態検出器１４の出力する発電機速度検出値及び発電機出力検出値を入力として、発電機の出力上限値及び出力下限値を消費電力指令演算器１６へ出力する。発電機出力制限値演算器１５は、発電機運転状態検出器１４からの発電機速度検出値及び発電機出力検出値に基づき、発電機１０の出力上限値及び出力下限値を算出する。 The generator output limit value calculator 15 receives the system output detection value output by the system output detector 13, the generator speed detection value and the generator output detection value output by the generator operating state detector 14, and inputs the generator output limit value. The output upper limit value and the output lower limit value are output to the power consumption command calculator 16. The generator output limit value calculator 15 calculates the output upper limit value and the output lower limit value of the generator 10 based on the generator speed detection value and the generator output detection value from the generator operating state detector 14.
　消費電力指令演算器１６は発電機出力制限値演算器１５の出力する出力上限値及び出力下限値、系統出力検出器１３の出力する系統出力検出値を入力として、電力消費器４に対する消費電力指令を出力する。 The power consumption command calculator 16 inputs the output upper limit value and the output lower limit value output from the generator output limit value calculator 15 and the system output detection value output from the system output detector 13 to the power consumption command for the power consumer 4. Is output.
　図２は、図１における発電機出力制限値演算器１５の構成を示す。発電機出力制限値演算器１５は、データベース１５１、変化率リミッタ１５２、加算器１５３、減算器１５４を有している。データベース１５１は発電機速度検出値及び発電機出力検出値を入力として、風車ブレード１１やギアなどの風車機械系が許容する発電機出力の変化幅及び変化率をそれぞれ変化幅設定値及び変化率設定値として出力する。変化率リミッタ１５２はデータベース１５１が出力する変化率設定値と系統出力検出値を入力として、変化率リミッタ１５２の出力が変化率設定値以下になるように変化率リミッタ処理を系統出力検出値に実施して、発電機出力基準値として出力する。 FIG. 2 shows the configuration of the generator output limit value calculator 15 in FIG. The generator output limit value calculator 15 has a database 151, a change rate limiter 152, an adder 153, and a subtractor 154. The database 151 receives the generator speed detection value and the generator output detection value as input, and sets the change width setting value and the change rate setting of the change width and the change rate of the generator output permitted by the wind turbine mechanical system such as the wind turbine blade 11 and the gear, respectively. Output as a value. The rate-of-change limiter 152 inputs the rate-of-change setting value and the system output detection value output from the database 151, and performs the rate-of-change limiter processing on the system output detection value so that the output of the rate-of-change limiter 152 becomes equal to or less than the rate-of-change setting value Then, it is output as the generator output reference value.
　加算器１５３は変化率リミッタ１５２が出力する発電機出力基準値とデータベース１５１が出力する変化幅設定値を入力として、それらの和を発電機の出力上限値として出力する。減算器１５４は変化率リミッタ１５２が出力する発電機出力基準値とデータベース１５１が出力する変化幅設定値を入力として、それらの差を発電機の出力下限値として出力する。 The adder 153 inputs the generator output reference value output by the change rate limiter 152 and the change width set value output by the database 151, and outputs the sum thereof as the output upper limit value of the generator. The subtractor 154 inputs the generator output reference value output by the change rate limiter 152 and the change width set value output by the database 151, and outputs the difference between them as the output lower limit value of the generator.
　つまり、発電機出力制限値演算器１５は、発電機速度検出値及び発電機出力検出値に対応する変化幅設定値及び変化率設定値を記憶したデータベース１５１を備えており、所定の変化幅設定値及び所定の変化率設定値に基づき、発電機１０の出力上限値及び出力下限値を変更する。また、変化幅設定値及び変化率設定値は、発電機１０の運転状態に応じて変化する。 That is, the generator output limit value calculator 15 includes a database 151 that stores the change width setting value and the change rate setting value corresponding to the generator speed detection value and the generator output detection value, and has a predetermined change width setting. The output upper limit value and the output lower limit value of the generator 10 are changed based on the value and the predetermined change rate set value. The change width set value and the change rate set value change according to the operating state of the generator 10.
　このような構成にすることで、発電機１０の速度や出力などの運転状態に応じて、発電機１０の出力上限値及び出力下限値は所定の差を維持しながら、系統出力が変化する方向に所定の変化率以下で変化することになる。発電機１０の出力は出力上限値及び出力下限値の間の領域に制御されるため、発電機１０の出力の急変を抑制することができる。これにより、例えば風車ブレード１１に代表されるような風車の機械系部品に与えるトルク変動を所定の範囲内に抑制し、風車の機械系部品の長寿命化を図ることができる。 With such a configuration, a direction in which the system output changes while maintaining a predetermined difference between the output upper limit value and the output lower limit value of the generator 10 according to operating conditions such as the speed and output of the generator 10 It will change at a predetermined rate or less. Since the output of the generator 10 is controlled in the region between the output upper limit value and the output lower limit value, it is possible to suppress a sudden change in the output of the generator 10. As a result, it is possible to suppress the torque fluctuation applied to the mechanical system components of the wind turbine such as the wind turbine blade 11 within a predetermined range, and to prolong the service life of the mechanical system components of the wind turbine.
　図３は、図１における消費電力指令演算器１６の構成を示す。消費電力指令演算器１６は、上下限リミッタ１６１、減算器１６２、下限リミッタ１６３を有している。上下限リミッタ１６１は系統出力検出値、出力上限値、出力下限値を入力として、出力上限値と出力下限値の間の値になるようにリミッタ処理を系統出力検出値に実施して、発電機出力指令として出力する。減算器１６２は上下限リミッタ１６１が出力する発電機出力指令と系統出力検出値を入力として、それらの差を演算して下限リミッタ１６３へ出力する。下限リミッタ１６３は減算器１６２の出力を入力として、下限が零のリミッタ処理を実施することで消費電力指令が負値にならないようにして、消費電力指令として出力する。 FIG. 3 shows the configuration of the power consumption command calculator 16 in FIG. The power consumption command calculator 16 has an upper / lower limit limiter 161, a subtractor 162, and a lower limit limiter 163. The upper and lower limiter 161 receives the system output detection value, the output upper limit value, and the output lower limit value as input, performs limiter processing on the system output detection value so that the value falls between the output upper limit value and the output lower limit value, and the generator output Output as an output command. The subtractor 162 receives the generator output command output from the upper and lower limit limiter 161 and the system output detection value as input, calculates the difference between them, and outputs the difference to the lower limit limiter 163. The lower limit limiter 163 receives the output of the subtractor 162 as input and performs limiter processing with a lower limit of zero to prevent the power consumption command from becoming a negative value and outputs it as a power consumption command.
　系統出力検出値が上下限リミッタ１６１の範囲内であれば、発電機出力指令は系統出力検出値と一致し、消費電力指令は零となる。電力変換装置１の回路損失等を微小量として無視すると、発電機出力は系統出力と一致する。 If the system output detection value is within the upper / lower limit limiter 161, the generator output command matches the system output detection value, and the power consumption command is zero. If the circuit loss of the power conversion device 1 is neglected as a minute amount, the generator output matches the system output.
　一方、系統出力検出値が低下して、上下限リミッタ１６１の出力下限値以下になると、消費電力指令は出力下限値と系統出力検出値の差で与えられ、電力消費器４でその値の電力が消費されることになる。発電機出力は電力消費器４で消費される電力と系統出力の和にほぼ等しいので、発電機出力は出力下限値と一致する。すなわち、系統出力が上下限リミッタ１６１の出力下限値以下になるまで低下しても、発電機出力は出力下限値以下にならないように、電力消費器４が電力を消費する。 On the other hand, when the system output detection value decreases and becomes less than or equal to the output lower limit value of the upper and lower limit limiter 161, the power consumption command is given by the difference between the output lower limit value and the system output detection value, and the power consumption of that value is calculated by the power consumer 4. Will be consumed. Since the generator output is almost equal to the sum of the power consumed by the power consumer 4 and the system output, the generator output matches the output lower limit value. That is, the power consumer 4 consumes power so that the generator output does not fall below the output lower limit even if the system output drops below the output lower limit of the upper and lower limiter 161.
　一方、系統出力検出値が上昇して、上下限リミッタ１６１の出力上限値以上になっても、消費電力指令は下限リミッタ１６３の影響で零となる。すなわち、発電機出力は系統出力と一致する。したがって、系統出力が上下限リミッタ１６１の出力上限値以上になるまで上昇すると、発電機出力も同様に出力上限値以上になるまで上昇する。発電機出力の上昇を抑制するためには、発電機１０以外に発電する要素が必要であるが、本実施例ではそのような要素はないので、発電機出力の上昇を抑制することはできない。 On the other hand, even if the system output detection value rises and exceeds the output upper limit value of the upper / lower limit limiter 161, the power consumption command becomes zero due to the influence of the lower limit limiter 163. That is, the generator output matches the system output. Therefore, when the system output rises to the output upper limit value of the upper and lower limiter 161, the generator output also rises to the output upper limit value or more. In order to suppress the increase in the generator output, an element for generating power is required in addition to the generator 10. However, in the present embodiment, there is no such element, so the increase in the generator output cannot be suppressed.
　以上より、系統出力検出値が上下限リミッタ１６１の出力下限値以下になる場合は、発電機出力は出力下限値以下にならないように動作し、発電機出力の低下を抑制することができる。系統出力検出値が上下限リミッタ１６１の出力上限値以上になる場合は、本実施例では発電機出力の上昇を抑制することができないが、後述する別の実施例で発電機出力の上昇を抑制する構成について説明する。 From the above, when the system output detection value is less than or equal to the output lower limit value of the upper and lower limit limiter 161, the generator output operates so as not to be less than or equal to the output lower limit value, and it is possible to suppress a decrease in the generator output. When the system output detection value is equal to or higher than the output upper limit value of the upper and lower limiter 161, it is not possible to suppress the increase in the generator output in this embodiment, but it is possible to suppress the increase in the generator output in another embodiment described later. The configuration will be described.
　図４は、図２におけるデータベース１５１の出力する変化幅設定値及び変化率設定値の特性の一例を示す。ここでは、発電機速度が低く、発電機出力が高い領域では、変化幅設定値及び変化率設定値を小さくしている。この領域は発電機の出力するトルクが大きいため、このような特性を持たせることで、風車の機械系部品に与えるトルク変動を所定の範囲内に抑制することが可能となり、風車の機械系部品の長寿命化を図ることができる。 FIG. 4 shows an example of the characteristics of the change width set value and the change rate set value output from the database 151 in FIG. Here, in the region where the generator speed is low and the generator output is high, the change width set value and the change rate set value are made small. Since the torque output from the generator is large in this region, it is possible to suppress the torque fluctuation given to the mechanical system parts of the wind turbine within a predetermined range by providing such characteristics, and the mechanical system parts of the wind turbine It is possible to extend the life of the.
　一方、その他の領域では、変化幅設定値を相対的に大きくすることで、風車の機械系部品が許容できる範囲で発電機１０の出力するトルクを変動させる。その結果、電力消費器４で消費する電力が低減することになり、風からのパワーの利用率低下を抑制することができる。 On the other hand, in other areas, the torque output from the generator 10 is changed within a range that the mechanical system parts of the wind turbine can tolerate by making the change width set value relatively large. As a result, the power consumed by the power consumption device 4 is reduced, and it is possible to suppress a reduction in the utilization rate of power from the wind.
　このように、発電機１０の運転状態に応じて、変化幅設定値及び変化率設定値を変更することで、風車の機械系部品に与えるトルク変動が厳しい運転領域では、変化率設定値及び変化幅設定値を小さく設定することで、発電機のトルク変動を抑制し、トルク変動が厳しくない運転領域では、変化率設定値及び変化幅設定値を大きく設定することで、風からのパワーの利用率低下を抑制することができる。なお、データベース１５１の出力する特性は図４に示す特性に限定するものではなく、それ以外の特性であっても良い。 As described above, by changing the change width set value and the change rate set value according to the operating state of the generator 10, the change rate set value and the change rate are changed in the operating region where the torque fluctuation applied to the mechanical system components of the wind turbine is severe. By setting the width setting value small, the torque fluctuation of the generator is suppressed, and in the operating region where the torque fluctuation is not severe, by setting the change rate setting value and the change width setting value large, the power from the wind is used. The rate decrease can be suppressed. The characteristics output from the database 151 are not limited to the characteristics shown in FIG. 4, and other characteristics may be used.
　図５に、本実施例の電力変換装置の動作波形例を示す。時間T1までは系統出力検出値はP0とする。発電機出力制限値演算器１５の構成から、発電機出力基準値は定常状態ではP0になる。出力上限値は発電機出力基準値に変化幅設定値ΔPを加算した値であり、出力下限値は発電機出力基準値から変化幅設定値ΔPを減算した値である。また、系統出力検出値がP0であることから、消費電力指令演算器１６の構成から発電機出力指令もP0となる。 FIG. 5 shows an example of operation waveforms of the power conversion device of this embodiment. The system output detection value is P0 until time T1. Due to the configuration of the generator output limit value calculator 15, the generator output reference value is P0 in the steady state. The output upper limit value is a value obtained by adding the change width setting value ΔP to the generator output reference value, and the output lower limit value is a value obtained by subtracting the change width setting value ΔP from the generator output reference value. Further, since the system output detection value is P0, the generator output command is also P0 due to the configuration of the power consumption command calculator 16.
　したがって、発電機出力指令から系統出力検出値を減算して求める消費電力指令は零となるため、電力消費器４で消費される電力は零となる。電力変換装置１の回路損失等を微小量として無視すると、電力消費器４で消費される電力が零の場合は発電機出力と系統出力は一致するので、発電機出力はP0となる。 Therefore, the power consumption command obtained by subtracting the system output detection value from the generator output command is zero, so the power consumed by the power consumer 4 is zero. If the circuit loss of the power converter 1 is neglected as a minute amount, when the power consumed by the power consumer 4 is zero, the generator output and the system output match, so the generator output becomes P0.
　次に、時間T1において系統事故が発生して系統電圧が仮に零になったとする。系統電圧が零であることから電力変換器３から電力系統１２へ電力供給することができなくなるため、系統出力検出値は零となる。系統出力検出値が零になることから、発電機出力指令は上下限リミッタ１６１の出力下限値P0-ΔPと一致し、発電機出力指令から系統出力検出値を減算して求める消費電力指令はP0-ΔPとなる。電力消費器４が消費電力指令に従ってP0-ΔPの電力を消費すると、系統出力検出値が零であることから発電機出力はP0-ΔPとなる。 Next, at time T1, a grid fault occurs and the grid voltage temporarily becomes zero. Since the system voltage is zero, power cannot be supplied from the power converter 3 to the power system 12, so the system output detection value becomes zero. Since the system output detection value becomes zero, the generator output command matches the output lower limit value P0-ΔP of the upper / lower limit limiter 161, and the power consumption command obtained by subtracting the system output detection value from the generator output command is P0. -It becomes ΔP. When the power consumer 4 consumes P0-ΔP power according to the power consumption command, the generator output becomes P0-ΔP because the system output detection value is zero.
　時間T1以降は、系統出力検出値が零であることから、発電機出力基準値は変化率設定値に従って減少し、出力上限値及び出力下限値も減少する。この結果、発電機出力指令は出力下限値と一致して減少することになる。したがって、発電機出力指令から系統出力検出値を減算して求める消費電力指令も減少する。電力消費器４が消費する電力が消費電力指令に従って減少すると、系統出力検出値が零であることから発電機出力も減少する。 After time T1, since the system output detection value is zero, the generator output reference value decreases according to the change rate setting value, and the output upper limit value and output lower limit value also decrease. As a result, the generator output command decreases in accordance with the output lower limit value. Therefore, the power consumption command obtained by subtracting the system output detection value from the generator output command also decreases. When the power consumed by the power consumer 4 decreases in accordance with the power consumption command, the generator output also decreases because the system output detection value is zero.
　次に、時間T2において系統事故が復旧して系統電圧が回復したとする。電力変換器３から電力系統１２へ電力供給することが可能となるため、系統出力検出値が上昇する。この系統出力検出値が上昇する挙動に関しては電力変換器３の制御方式に依存するため、いろいろなケースが考えられる。ここではP0まで一旦上昇し、その後動揺しながら定常値P0に向かって収束する波形で説明するが、その限りではない。 Next, at time T2, assume that the system fault has been restored and the system voltage has been restored. Since the power can be supplied from the power converter 3 to the power system 12, the system output detection value increases. The behavior in which the system output detection value rises depends on the control method of the power converter 3, and therefore various cases are possible. Here, a waveform that rises to P0 and then converges toward a steady value P0 while swaying is described, but the waveform is not limited to this.
　また、時間T2において、系統出力検出値がP0まで上昇すると、発電機出力指令は出力上限値とP0の値の小さい方まで上昇するが、本実施例では出力上限値＜P0として、発電機出力指令は出力上限値まで上昇するとする。この時、発電機出力指令から系統出力検出値を減算した値は負値となるが、下限リミッタ１６３の作用により消費電力指令は零となり、電力消費器４で消費される電力は零となる。電力消費器４で消費される電力が零の場合は発電機出力と系統出力は一致するので、発電機出力はP0となる。 Further, at time T2, when the system output detection value rises to P0, the generator output command rises to the smaller one of the output upper limit value and the value of P0, but in this embodiment, the output upper limit value <P0 It is assumed that the command rises to the output upper limit value. At this time, the value obtained by subtracting the system output detection value from the generator output command becomes a negative value, but the power consumption command becomes zero due to the action of the lower limit limiter 163, and the power consumed by the power consumer 4 becomes zero. When the power consumed by the power consumer 4 is zero, the generator output and the system output match, so the generator output is P0.
　時間T2以降は、系統出力検出値がP0付近にあるため、発電機出力基準値は変化率設定値に従って増加し、出力上限値及び出力下限値も上昇する。この結果、発電機出力指令は出力上限値と一致して増加するが、発電機出力指令から系統出力検出値を減算した値は負値を維持するため、下限リミッタ１６３の作用により消費電力指令は零となり、電力消費器４で消費される電力は零となる。電力消費器４で消費される電力が零の場合は発電機出力と系統出力は一致するので、発電機出力は系統出力検出値と一致する。 After time T2, the system output detection value is near P0, so the generator output reference value increases according to the change rate setting value, and the output upper limit value and output lower limit value also increase. As a result, the generator output command increases in accordance with the output upper limit value, but since the value obtained by subtracting the system output detection value from the generator output command maintains a negative value, the lower limit limiter 163 acts to reduce the power consumption command. It becomes zero, and the power consumed by the power consumer 4 becomes zero. When the power consumed by the power consumer 4 is zero, the generator output and the system output match, so the generator output matches the system output detection value.
　次に、時間T3以降において、系統出力検出値が上下限リミッタ１６１の上下限範囲内に入るようになると、発電機出力指令は系統出力検出値と一致するようになる。発電機出力指令から系統出力検出値を減算した値は零であることから消費電力指令は零となり、電力消費器４で消費される電力は零となる。電力消費器４で消費される電力が零の場合は発電機出力と系統出力は一致するので、発電機出力は系統出力検出値と一致する。つまり、出力上限値及び出力下限値は、所定の差分値（ΔP）を維持しながら変化する。また、差分値（ΔP）は、発電機１０の運転状態に応じて変化する。 Next, after time T3, when the system output detection value falls within the upper and lower limit range of the upper and lower limiter 161, the generator output command will match the system output detection value. Since the value obtained by subtracting the system output detection value from the generator output command is zero, the power consumption command becomes zero, and the power consumed by the power consumer 4 becomes zero. When the power consumed by the power consumer 4 is zero, the generator output and the system output match, so the generator output matches the system output detection value. That is, the output upper limit value and the output lower limit value change while maintaining the predetermined difference value (ΔP). Further, the difference value (ΔP) changes according to the operating state of the generator 10.
　以上説明したように、本実施例の電力変換装置１は、風車の軸に接続された発電機１０の出力する可変周波数の交流電力を直流電力に変換する第１の電力変換器（電力変換器２）と、直流電力を商用周波数の交流電力に変換して電力系統１２に供給する第２の電力変換器（電力変換器３）と、第１の電力変換器（電力変換器２）と第２の電力変換器（電力変換器３）の間に接続され、直流電力を制御する直流電力制御器（電力消費器４）と、可変周波数の交流電力および商用周波数の交流電力に基づき、直流電力制御器（電力消費器４）を制御する制御部９と、を備え、制御部９は、可変周波数の交流電力に基づき、発電機１０の運転状態を検出する発電機運転状態検出器１４と、商用周波数の交流電力に基づき、電力系統１２の系統出力を検出する系統出力検出器１３と、発電機運転状態検出器１４の出力、および系統出力検出器１３の出力に基づき、発電機１０の出力制限値を演算する発電機出力制限値演算器１５と、発電機出力制限値演算器１５の出力、および系統出力検出器１３の出力に基づき、直流電力制御器（電力消費器４）に対する電力指令を演算する電力指令演算器（消費電力指令演算器１６）と、を有し、電力指令演算器（消費電力指令演算器１６）からの電力指令（消費電力指令）に基づき、発電機１０の出力が出力制限値の範囲内に収まるように、直流電力制御器（電力消費器４）により直流電力を制御する。 As described above, the power converter 1 of the present embodiment is the first power converter (power converter) that converts the variable frequency AC power output from the generator 10 connected to the shaft of the wind turbine into DC power. 2), a second power converter (power converter 3) that converts DC power into AC power of commercial frequency and supplies the power to the power grid 12, a first power converter (power converter 2), and a second power converter (power converter 2). DC power controller connected between two power converters (power converter 3) and controlling DC power (power consumer 4), and DC power based on variable frequency AC power and commercial frequency AC power. A control unit 9 for controlling the controller (power consumption device 4), and the control unit 9 detects the operating state of the generator 10 based on the alternating-current power of a variable frequency; The output of the generator 10 based on the output of the grid output detector 13 that detects the grid output of the grid 12 based on the commercial frequency AC power, the output of the generator operating state detector 14, and the output of the grid output detector 13. Based on the output of the generator output limit value calculator 15 for calculating the limit value, the output of the generator output limit value calculator 15, and the output of the system output detector 13, a power command to the DC power controller (power consumer 4) And a power command calculator (power consumption command calculator 16) for calculating the output of the generator 10 based on the power command (power consumption command) from the power command calculator (power consumption command calculator 16). The DC power is controlled by the DC power controller (power consumer 4) so that the power consumption value is within the range of the output limit value.
　以上のように、本実施例では、系統出力検出値が急峻に低下するようなケースにおいても、電力消費器４で電力を消費することで、発電機出力の低下は系統出力に比べて抑制される。この結果、風車ブレード１１やギアなどの風車機械系に与えるトルク変動を緩和し、風車機械系の長寿命化を図ることができる。 As described above, in the present embodiment, even in the case where the system output detection value sharply decreases, the power consumption by the power consumption unit 4 suppresses the decrease in the generator output as compared with the system output. It As a result, it is possible to mitigate the fluctuation of torque applied to the wind turbine mechanical system such as the wind turbine blade 11 and the gear, and to extend the life of the wind turbine mechanical system.
　また、本実施例で示すように、データベース１５１が出力する変化幅設定値を小さく設定すると、消費電力指令は大きくなり、変化幅設定値を大きく設定すると、消費電力指令は小さくなる。また、データベース１５１が出力する変化率設定値を小さく設定すると、消費電力指令は大きくなり、変化率設定値を大きく設定すると、消費電力指令は小さくなる。すなわち、変化幅設定値及び変化率設定値を調整することで、電力消費器４で消費する電力を調整することができる。風車機械系部品が許容する範囲で変化幅設定値及び変化率設定値を大きく設定することで、電力消費器４で消費する電力を低減し、風からのパワー（風力）の利用率の低下を抑制することができる。 Further, as shown in the present embodiment, when the change width set value output from the database 151 is set small, the power consumption command becomes large, and when the change width set value is set large, the power consumption command becomes small. Further, when the change rate set value output from the database 151 is set small, the power consumption command becomes large, and when the change rate set value is set large, the power consumption command becomes small. That is, the power consumed by the power consuming device 4 can be adjusted by adjusting the change width setting value and the change rate setting value. By setting the change width setting value and the change rate setting value large within the range permitted by the wind turbine mechanical system parts, the power consumed by the power consumption device 4 is reduced and the utilization rate of the power from the wind (wind force) is reduced. Can be suppressed.
　図６から図８を参照して、本発明の実施例２の電力変換装置とその制御方法について説明する。図６は、本実施例の電力変換装置の構成を示す図である。本実施例の電力変換装置１７は、主要な構成として、電力変換器２、電力変換器３、蓄電装置１８、電圧検出器５、電流検出器６、電圧検出器７、電流検出器８、制御部１９を有している。 A power conversion device and a control method thereof according to a second embodiment of the present invention will be described with reference to FIGS. 6 to 8. FIG. 6 is a diagram showing the configuration of the power conversion device according to the present embodiment. The power converter 17 of this embodiment has, as its main components, a power converter 2, a power converter 3, a power storage device 18, a voltage detector 5, a current detector 6, a voltage detector 7, a current detector 8, and control. It has a section 19.
　実施例１の電力変換装置１と異なる点は、電力消費器４の代わりに蓄電装置１８を備えていること、消費電力指令演算器１６の代わりに充電電力指令演算器２０を備えていることである。それ以外に関しては実施例１の電力変換装置１と同様であるため、繰り返しとなる詳細な説明は省略する。 The difference from the power conversion device 1 of the first embodiment is that a power storage device 18 is provided instead of the power consumption device 4, and a charging power command computing device 20 is provided instead of the power consumption command computing device 16. is there. Other than that, since it is the same as the power conversion device 1 of the first embodiment, detailed description that is repeated will be omitted.
　蓄電装置１８は充電電力指令演算器２０からの充電電力指令に応じて電力変換器２と電力変換器３の直流部から電力を充電したり、電力変換器２と電力変換器３の直流部へ電力を放電したりする。充電電力指令演算器２０は発電機出力制限値演算器１５の出力する出力上限値及び出力下限値、系統出力検出器１３の出力する系統出力検出値を入力として、蓄電装置１８に対する充電電力指令を出力する。 The power storage device 18 charges electric power from the DC parts of the power converter 2 and the power converter 3 in response to the charging power command from the charging power command calculator 20, or charges the DC parts of the power converter 2 and the power converter 3 to each other. Discharge electricity. The charging power command calculator 20 receives the output upper limit value and the output lower limit value output from the generator output limit value calculator 15, and the system output detection value output from the system output detector 13 as an input, and issues a charging power command to the power storage device 18. Output.
　図７は、図６における充電電力指令演算器２０の構成を示す。充電電力指令演算器２０は、上下限リミッタ２０１、減算器２０２を有している。上下限リミッタ２０１は系統出力検出値、出力上限値、出力下限値を入力として、出力上限値と出力下限値の間の値になるようにリミッタ処理を系統出力検出値に実施して、発電機出力指令として出力する。減算器２０２は上下限リミッタ２０１が出力する発電機出力指令と系統出力検出値を入力として、それらの差を演算して充電電力指令として出力する。ここで、充電電力指令が正値の場合は充電の電力指令を、負値の場合は放電の電力指令を表す。 FIG. 7 shows the configuration of the charging power command calculator 20 in FIG. The charging power command calculator 20 has an upper and lower limit limiter 201 and a subtractor 202. The upper / lower limit limiter 201 receives the system output detection value, the output upper limit value, and the output lower limit value as input, performs limiter processing on the system output detection value so that the value falls between the output upper limit value and the output lower limit value, and the generator output. Output as an output command. The subtracter 202 receives the generator output command output by the upper and lower limit limiter 201 and the system output detection value, calculates the difference between them, and outputs the charging power command. Here, when the charging power command has a positive value, it represents a charging power command, and when it has a negative value, it represents a discharging power command.
　系統出力検出値が上下限リミッタ２０１の範囲内であれば、発電機出力指令は系統出力検出値と一致し、充電電力指令は零となり、蓄電装置１８で充放電される電力は零となる。蓄電装置１８で充放電される電力が零の場合は発電機出力と系統出力は一致する。 If the system output detection value is within the range of the upper / lower limit limiter 201, the generator output command matches the system output detection value, the charging power command becomes zero, and the power charged / discharged by the power storage device 18 becomes zero. When the electric power charged and discharged in the power storage device 18 is zero, the generator output and the system output match.
　一方、系統出力検出値が低下して、上下限リミッタ２０１の出力下限値以下になると、充電電力指令は出力下限値と系統出力検出値の差で与えられる正値となり、蓄電装置１８はその値の電力を充電することになる。発電機出力は蓄電装置１８に充電される電力と系統出力の和にほぼ等しいので、発電機出力は出力下限値と一致する。 On the other hand, when the system output detection value decreases and becomes less than or equal to the output lower limit value of the upper / lower limit limiter 201, the charging power command becomes a positive value given by the difference between the output lower limit value and the system output detection value, and the power storage device 18 has that value. Will be charged with electricity. Since the generator output is substantially equal to the sum of the electric power charged in the power storage device 18 and the system output, the generator output matches the output lower limit value.
　すなわち、系統出力が上下限リミッタ２０１の出力下限値以下になるまで低下しても、発電機出力は出力下限値以下にならないように、蓄電装置１８が電力を充電する。 That is, the power storage device 18 charges electric power so that the generator output does not fall below the output lower limit even if the system output falls below the output lower limit of the upper / lower limit limiter 201.
　一方、系統出力検出値が上昇して、上下限リミッタ２０１の出力上限値以上になると、充電電力指令は出力上限値と系統出力検出値の差で与えられる負値となり、蓄電装置１８はその値の大きさの電力を放電することになる。発電機出力は系統出力と蓄電装置１８から放電される電力の差にほぼ等しいので、発電機出力は出力上限値と一致する。 On the other hand, when the system output detection value rises and becomes equal to or higher than the output upper limit value of the upper / lower limit limiter 201, the charging power command becomes a negative value given by the difference between the output upper limit value and the system output detection value, and the power storage device 18 has that value. The amount of electric power will be discharged. Since the generator output is substantially equal to the difference between the system output and the electric power discharged from the power storage device 18, the generator output matches the output upper limit value.
　すなわち、系統出力が上下限リミッタ２０１の出力上限値以上になるまで上昇しても、発電機出力は出力上限値以上にならないように、蓄電装置１８が電力を放電する。 That is, the power storage device 18 discharges electric power so that the generator output does not exceed the output upper limit value even if the system output rises above the output upper limit value of the upper and lower limiter 201.
　以上より、系統出力検出値が上下限リミッタ２０１の出力下限値以下になる場合は、蓄電装置１８が充電することで発電機出力が出力下限値以下にならないように動作し、系統出力検出値が上下限リミッタ２０１の出力上限値以上になる場合は、蓄電装置１８が放電することで発電機出力が出力上限値以上にならないように動作する。このような動作により、発電機出力の低下あるいは上昇を抑制することができる。 From the above, when the system output detection value is less than or equal to the output lower limit value of the upper and lower limit limiter 201, the power storage device 18 is charged to operate so that the generator output does not fall below the output lower limit value, and the system output detection value When the output exceeds the output upper limit of the upper / lower limit limiter 201, the power storage device 18 discharges to operate so that the generator output does not exceed the output upper limit. By such an operation, it is possible to suppress a decrease or an increase in the generator output.
　図８に、本実施例の電力変換装置の動作波形例を示す。時間T1までは系統出力検出値はP0とする。発電機出力制限値演算器１５の構成（図２）から、発電機出力基準値は定常状態ではP0になる。出力上限値は発電機出力基準値に変化幅設定値ΔPを加算した値であり、出力下限値は発電機出力基準値から変化幅設定値ΔPを減算した値である。また、系統出力検出値がP0であることから、充電電力指令演算器２０の構成から発電機出力指令もP0となる。 FIG. 8 shows an example of operation waveforms of the power conversion device of this embodiment. The system output detection value is P0 until time T1. From the configuration of the generator output limit value calculator 15 (FIG. 2), the generator output reference value is P0 in the steady state. The output upper limit value is a value obtained by adding the change width setting value ΔP to the generator output reference value, and the output lower limit value is a value obtained by subtracting the change width setting value ΔP from the generator output reference value. Further, since the system output detection value is P0, the generator output command is also P0 due to the configuration of the charging power command calculator 20.
　したがって、発電機出力指令から系統出力検出値を減算して求める充電電力指令は零となるため、蓄電装置１８で充電される電力は零となる。電力変換装置１７の回路損失等を微小量として無視すると、蓄電装置１８で充電される電力が零の場合は発電機出力と系統出力は一致するので、発電機出力はP0となる。 Therefore, the charging power command obtained by subtracting the system output detection value from the generator output command becomes zero, so the power charged in the power storage device 18 becomes zero. If the circuit loss or the like of the power conversion device 17 is neglected as a minute amount, when the electric power charged in the power storage device 18 is zero, the generator output and the system output match, so the generator output becomes P0.
　次に、時間T1において系統事故が発生して系統電圧が仮に零になったとする。系統電圧が零であることから電力変換器３から電力系統１２へ電力供給することができなくなるため、系統出力検出値は零となる。系統出力検出値が零になることから、発電機出力指令は上下限リミッタ２０１の出力下限値P0-ΔPと一致し、発電機出力指令から系統出力検出値を減算して求める充電電力指令はP0-ΔPとなる。蓄電装置１８が充電電力指令に従ってP0-ΔPの電力を充電すると、系統出力検出値が零であることから発電機出力はP0-ΔPとなる。 Next, at time T1, a grid fault occurs and the grid voltage temporarily becomes zero. Since the system voltage is zero, power cannot be supplied from the power converter 3 to the power system 12, so the system output detection value becomes zero. Since the system output detection value becomes zero, the generator output command matches the output lower limit value P0-ΔP of the upper / lower limit limiter 201, and the charging power command obtained by subtracting the system output detection value from the generator output command is P0. -It becomes ΔP. When the power storage device 18 charges the power of P0-ΔP according to the charging power command, the generator output becomes P0-ΔP because the system output detection value is zero.
　時間T1以降は、系統出力検出値が零であることから、発電機出力基準値は変化率設定値に従って減少し、出力上限値及び出力下限値も減少する。この結果、発電機出力指令は出力下限値と一致して減少することになる。したがって、発電機出力指令から系統出力検出値を減算して求める充電電力指令も減少する。蓄電装置１８が充電する電力が充電電力指令に従って減少すると、系統出力検出値が零であることから発電機出力も減少する。 After time T1, since the system output detection value is zero, the generator output reference value decreases according to the change rate setting value, and the output upper limit value and output lower limit value also decrease. As a result, the generator output command decreases in accordance with the output lower limit value. Therefore, the charging power command obtained by subtracting the system output detection value from the generator output command also decreases. When the electric power charged by power storage device 18 decreases in accordance with the charging power command, the system output detection value is zero, so the generator output also decreases.
　次に、時間T2において系統事故が復旧して系統電圧が回復したとする。電力変換器３から電力系統１２へ電力供給することが可能となるため、系統出力検出値が上昇する。この系統出力検出値が上昇する挙動に関しては電力変換器３の制御方式に依存するため、いろいろなケースが考えられる。ここではP0まで一旦上昇し、その後動揺しながら定常値P0に向かって収束する波形で説明するが、その限りではない。 Next, at time T2, assume that the system fault has been restored and the system voltage has been restored. Since the power can be supplied from the power converter 3 to the power system 12, the system output detection value increases. The behavior in which the system output detection value rises depends on the control method of the power converter 3, and therefore various cases are possible. Here, a waveform that rises to P0 and then converges toward a steady value P0 while swaying is described, but the waveform is not limited to this.
　また、時間T2において、系統出力検出値がP0まで上昇すると、発電機出力指令は出力上限値とP0の値の小さい方まで上昇するが、本実施例では出力上限値＜P0として、発電機出力指令は出力上限値まで上昇するとする。この時、発電機出力指令から系統出力検出値を減算した値は負値となり、充電電力指令は負値であることから放電指令となる。蓄電装置１８から電力が放電されることで、発電機出力は出力上限値と一致する。 Further, at time T2, when the system output detection value rises to P0, the generator output command rises to the smaller one of the output upper limit value and the value of P0, but in this embodiment, the output upper limit value <P0 It is assumed that the command rises to the output upper limit value. At this time, the value obtained by subtracting the system output detection value from the generator output command becomes a negative value, and the charging power command becomes a negative value, so it becomes a discharge command. The power output from the power storage device 18 causes the generator output to match the output upper limit value.
　時間T2以降は、系統出力検出値がP0付近にあるため、発電機出力基準値は変化率設定値に従って増加し、出力上限値及び出力下限値も上昇する。この結果、発電機出力指令は出力上限値と一致して増加するが、蓄電装置１８から電力が放電されることで、発電機出力は出力上限値と一致する。 After time T2, the system output detection value is near P0, so the generator output reference value increases according to the change rate setting value, and the output upper limit value and output lower limit value also increase. As a result, the generator output command increases in accordance with the output upper limit value, but the power output from the power storage device 18 causes the generator output to match the output upper limit value.
　次に、時間T3以降において、系統出力検出値が上下限リミッタ２０１の上下限範囲内に入るようになると、発電機出力指令は系統出力検出値と一致するようになる。発電機出力指令から系統出力検出値を減算した値は零であることから充電電力指令は零となり、蓄電装置１８で充放電される電力は零となる。蓄電装置１８で充放電される電力が零の場合は発電機出力と系統出力は一致するので、発電機出力は系統出力検出値と一致する。 Next, after the time T3, when the system output detection value comes into the upper and lower limit range of the upper and lower limiter 201, the generator output command will match the system output detection value. Since the value obtained by subtracting the system output detection value from the generator output command is zero, the charging power command is zero, and the power charged and discharged in the power storage device 18 is zero. When the electric power charged and discharged in the power storage device 18 is zero, the generator output and the system output match, so the generator output matches the system output detection value.
　以上のように、本実施例では、系統出力検出値が急峻に低下するようなケースにおいては、蓄電装置１８が電力を充電することで、発電機出力の低下は系統出力に比べて抑制される。また、系統出力検出値が急峻に上昇するようなケースにおいては、蓄電装置１８が電力を放電することで、発電機出力の上昇は系統出力に比べて抑制される。この結果、風車ブレード１１やギアなどの風車機械系に与えるトルク変動を緩和し、風車機械系の長寿命化を図ることができる。 As described above, in the present embodiment, in a case where the system output detection value sharply decreases, the power storage device 18 charges the power, so that the decrease in the generator output is suppressed as compared with the system output. .. In addition, in a case where the system output detection value sharply increases, the power storage device 18 discharges electric power, so that the increase in the generator output is suppressed as compared with the system output. As a result, it is possible to mitigate the fluctuation of torque applied to the wind turbine mechanical system such as the wind turbine blade 11 and the gear, and to extend the life of the wind turbine mechanical system.
　また、本実施例では蓄電装置１８で充放電することで、実施例１に比べて風からのパワー（風力）の利用率向上を図ることができる。 In addition, in the present embodiment, by charging and discharging the power storage device 18, it is possible to improve the utilization rate of power from the wind (wind power) compared to the first embodiment.
　なお、本発明は上記した実施例に限定されるものではなく、様々な変形例が含まれる。例えば、上記した実施例は本発明を分かりやすく説明するために詳細に説明したものであり、必ずしも説明した全ての構成を備えるものに限定されるものではない。また、ある実施例の構成の一部を他の実施例の構成に置き換えることが可能であり、また、ある実施例の構成に他の実施例の構成を加えることも可能である。また、各実施例の構成の一部について、他の構成の追加・削除・置換をすることが可能である。 The present invention is not limited to the above-described embodiments, but includes various modifications. For example, the above-described embodiments have been described in detail in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the configurations described. Further, a part of the configuration of a certain embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of a certain embodiment. Further, with respect to a part of the configuration of each embodiment, other configurations can be added / deleted / replaced.
　１…電力変換装置、２…電力変換器、３…電力変換器、４…電力消費器、５…電圧検出器、６…電流検出器、７…電圧検出器、８…電流検出器、９…制御部、１０…発電機、１１…風車ブレード、１２…電力系統、１３…系統出力検出器、１４…発電機運転状態検出器、１５…発電機出力制限値演算器、１５１…データベース、１５２…変化率リミッタ、１５３…加算器、１５４…減算器、１６…消費電力指令演算器、　１６１…上下限リミッ１６２…減算器、１６３…下限リミッタ、１７…電力変換装置、１８…蓄電装置、１９…制御部、２０…充電電力指令演算器、２０１…上下限リミッタ、２０２…減算器 DESCRIPTION OF SYMBOLS 1 ... Power converter device, 2 ... Power converter, 3 ... Power converter, 4 ... Power consumer, 5 ... Voltage detector, 6 ... Current detector, 7 ... Voltage detector, 8 ... Current detector, 9 ... Control unit, 10 ... Generator, 11 ... Wind turbine blade, 12 ... Power system, 13 ... System output detector, 14 ... Generator operating state detector, 15 ... Generator output limit value calculator, 151 ... Database, 152 ... Change rate limiter, 153 ... Adder, 154 ... Subtractor, 16 ... Power consumption command calculator, 161 ... Upper / lower limit limit 162 ... Subtractor, 163 ... Lower limit limiter, 17 ... Power conversion device, 18 ... Power storage device, 19 ... Control unit, 20 ... Charging power command calculator, 201 ... Upper and lower limit limiter, 202 ... Subtractor

Claims (15)

  1. 　風車の軸に接続された発電機の出力する可変周波数の交流電力を直流電力に変換する第１の電力変換器と、
    　前記直流電力を商用周波数の交流電力に変換して電力系統に供給する第２の電力変換器と、
    　前記第１の電力変換器と前記第２の電力変換器の間に接続され、前記直流電力を制御する直流電力制御器と、
    　前記可変周波数の交流電力および前記商用周波数の交流電力に基づき、前記直流電力制御器を制御する制御部と、を備え、
    　前記制御部は、前記可変周波数の交流電力に基づき、前記発電機の運転状態を検出する発電機運転状態検出器と、
    　前記商用周波数の交流電力に基づき、前記電力系統の系統出力を検出する系統出力検出器と、
    　前記発電機運転状態検出器の出力、および前記系統出力検出器の出力に基づき、前記発電機の出力制限値を演算する発電機出力制限値演算器と、
    　前記発電機出力制限値演算器の出力、および前記系統出力検出器の出力に基づき、前記直流電力制御器に対する電力指令を演算する電力指令演算器と、を有し、
    　前記電力指令演算器からの電力指令に基づき、前記発電機の出力が前記出力制限値の範囲内に収まるように、前記直流電力制御器により前記直流電力を制御することを特徴とする電力変換装置。     A first power converter for converting variable frequency AC power output from a generator connected to the shaft of the wind turbine into DC power;
    A second power converter for converting the DC power into AC power having a commercial frequency and supplying the AC power to a power grid;
    A DC power controller connected between the first power converter and the second power converter to control the DC power;
    A control unit for controlling the DC power controller based on the variable frequency AC power and the commercial frequency AC power;
    The control unit is based on the variable frequency AC power, a generator operating state detector that detects the operating state of the generator,
    A system output detector that detects a system output of the power system based on the AC power of the commercial frequency,
    Based on the output of the generator operating state detector, and the output of the system output detector, a generator output limit value calculator that calculates the output limit value of the generator,
    Based on the output of the generator output limit value calculator and the output of the system output detector, a power command calculator for calculating a power command to the DC power controller, and
    Based on a power command from the power command calculator, the DC power controller controls the DC power so that the output of the generator falls within the range of the output limit value. ..
  2. 　請求項１に記載の電力変換装置であって、
    　前記直流電力制御器は、前記直流電力を消費する電力消費器であることを特徴とする電力変換装置。     The power conversion device according to claim 1, wherein
    The DC power controller is a power consumer that consumes the DC power.
  3. 　請求項１に記載の電力変換装置であって、
    　前記直流電力制御器は、前記直流電力を充放電する蓄電装置であることを特徴とする電力変換装置。     The power conversion device according to claim 1, wherein
    The DC power controller is a power storage device that charges and discharges the DC power.
  4. 　請求項１から３のいずれか１項に記載の電力変換装置であって、
    　前記発電機出力制限値演算器は、前記発電機運転状態検出器からの発電機速度検出値及び発電機出力検出値に基づき、前記発電機の出力上限値及び出力下限値を算出することを特徴とする電力変換装置。     The power conversion device according to any one of claims 1 to 3,
    The generator output limit value calculator calculates an output upper limit value and an output lower limit value of the generator based on the generator speed detection value and the generator output detection value from the generator operating state detector. Power conversion device.
  5. 　請求項４に記載の電力変換装置であって、
    　前記発電機出力制限値演算器は、前記発電機速度検出値及び前記発電機出力検出値に対応する変化幅設定値及び変化率設定値を記憶したデータベースを備え、
    　所定の変化幅設定値及び所定の変化率設定値に基づき、前記発電機の出力上限値及び出力下限値を変更することを特徴とする電力変換装置。     The power conversion device according to claim 4, wherein
    The generator output limit value calculator comprises a database that stores a change width set value and a change rate set value corresponding to the generator speed detection value and the generator output detection value,
    An electric power converter characterized by changing an output upper limit value and an output lower limit value of the generator based on a predetermined change width set value and a predetermined change rate set value.
  6. 　請求項５に記載の電力変換装置であって、
    　前記変化幅設定値及び前記変化率設定値は、前記発電機の運転状態に応じて変化することを特徴とする電力変換装置。     The power conversion device according to claim 5, wherein
    The power conversion device, wherein the change width set value and the change rate set value change according to an operating state of the generator.
  7. 　請求項５に記載の電力変換装置であって、
    　前記出力上限値及び前記出力下限値は、所定の差分値を維持しながら変化することを特徴とする電力変換装置。     The power conversion device according to claim 5, wherein
    The power conversion device, wherein the output upper limit value and the output lower limit value change while maintaining a predetermined difference value.
  8. 　請求項７に記載の電力変換装置であって、
    　前記差分値は、前記発電機の運転状態に応じて変化することを特徴とする電力変換装置。     The power conversion device according to claim 7, wherein
    The power converter according to claim 1, wherein the difference value changes according to an operating state of the generator.
  9. 　電力系統に連系される風力発電システム向け電力変換装置の制御方法であって、
    　発電機から出力される可変周波数の交流電力に基づき、前記発電機の運転状態を検出し、
    　前記電力系統へ供給される商用周波数の交流電力に基づき、前記電力系統への系統出力を検出し、
    　前記検出した発電機の運転状態、および前記検出した系統出力に基づき、前記発電機の出力制限値を算出し、
    　前記算出した出力制限値、および前記検出した系統出力に基づき、前記発電機から出力される可変周波数の交流電力と前記電力系統へ供給される商用周波数の交流電力間の直流電力を制御する電力指令値を算出し、
    　当該算出した電力指令値に基づき、前記直流電力を制御することを特徴とする電力変換装置の制御方法。     A method for controlling a power conversion device for a wind power generation system connected to a power system, comprising:
    Based on the variable frequency AC power output from the generator, detects the operating state of the generator,
    Based on the commercial frequency AC power supplied to the power system, detects the system output to the power system,
    Based on the detected operating state of the generator and the detected system output, calculate the output limit value of the generator,
    A power command for controlling direct-current power between variable-frequency alternating-current power output from the generator and commercial-frequency alternating-current power supplied to the power system, based on the calculated output limit value and the detected system output. Calculate the value,
    A method of controlling a power converter, comprising controlling the DC power based on the calculated power command value.
  10. 　請求項９に記載の電力変換装置の制御方法であって、
    　前記電力指令値に基づき、電力消費器により前記直流電力を消費することを特徴とする電力変換装置の制御方法。     The control method of the power converter according to claim 9,
    A method of controlling a power converter, wherein the DC power is consumed by a power consumer based on the power command value.
  11. 　請求項９に記載の電力変換装置の制御方法であって、
    　前記電力指令値に基づき、蓄電装置により前記直流電力を充放電することを特徴とする電力変換装置の制御方法。     The control method of the power converter according to claim 9,
    A method of controlling a power conversion device, comprising charging and discharging the DC power with a power storage device based on the power command value.
  12. 　請求項９から１１のいずれか１項に記載の電力変換装置の制御方法であって、
    　前記発電機の発電機速度及び発電機出力に基づき、前記発電機の出力上限値及び出力下限値を算出することを特徴とする電力変換装置の制御方法。     It is a control method of the power converter according to any one of claims 9 to 11,
    A control method for a power converter, comprising: calculating an output upper limit value and an output lower limit value of the generator based on a generator speed and a generator output of the generator.
  13. 　請求項１２に記載の電力変換装置の制御方法であって、
    　所定の変化幅設定値及び所定の変化率設定値に基づき、前記発電機の出力上限値及び出力下限値を変更することを特徴とする電力変換装置の制御方法。     It is a control method of the power converter according to claim 12,
    A control method for a power converter, comprising changing an output upper limit value and an output lower limit value of the generator based on a predetermined change width set value and a predetermined change rate set value.
  14. 　請求項１３に記載の電力変換装置の制御方法であって、
    　前記変化幅設定値及び前記変化率設定値は、前記発電機の運転状態に応じて変化することを特徴とする電力変換装置の制御方法。     The method of controlling the power conversion device according to claim 13,
    The control method for a power converter, wherein the change width set value and the change rate set value change according to an operating state of the generator.
  15. 　請求項１３に記載の電力変換装置の制御方法であって、
    　前記出力上限値及び前記出力下限値は、所定の差分値を維持しながら変化することを特徴とする電力変換装置の制御方法。     The method of controlling the power conversion device according to claim 13,
    The control method for a power converter, wherein the output upper limit value and the output lower limit value change while maintaining a predetermined difference value.
PCT/JP2019/033059 2018-11-16 2019-08-23 Electric power converting device, and method for controlling electric power converting device WO2020100372A1 (en)

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