WO2021220488A1 - 電力変換装置 - Google Patents

電力変換装置 Download PDF

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Publication number
WO2021220488A1
WO2021220488A1 PCT/JP2020/018323 JP2020018323W WO2021220488A1 WO 2021220488 A1 WO2021220488 A1 WO 2021220488A1 JP 2020018323 W JP2020018323 W JP 2020018323W WO 2021220488 A1 WO2021220488 A1 WO 2021220488A1
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WO
WIPO (PCT)
Prior art keywords
power
voltage
circuit
frequency
distribution system
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/JP2020/018323
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English (en)
French (fr)
Japanese (ja)
Inventor
禎之 井上
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Mitsubishi Electric Corp
Original Assignee
Mitsubishi Electric Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Mitsubishi Electric Corp filed Critical Mitsubishi Electric Corp
Priority to CN202080100113.2A priority Critical patent/CN115428323B/zh
Priority to US17/913,849 priority patent/US12166427B2/en
Priority to PCT/JP2020/018323 priority patent/WO2021220488A1/ja
Priority to JP2022518561A priority patent/JP7345644B2/ja
Publication of WO2021220488A1 publication Critical patent/WO2021220488A1/ja
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of AC power input into DC power output; Conversion of DC power input into AC power output
    • H02M7/42—Conversion of DC power input into AC power output without possibility of reversal
    • H02M7/44—Conversion of DC power input into AC power output without possibility of reversal by static converters
    • H02M7/48—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0067—Converter structures employing plural converter units, other than for parallel operation of the units on a single load
    • H02M1/007—Plural converter units in cascade
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—ELECTRIC POWER NETWORKS; 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 feeding a single network from two or more generators or sources in parallel; Arrangements for feeding already energised networks from additional generators or sources in parallel
    • H02J3/381—Dispersed generators
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—ELECTRIC POWER NETWORKS; 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 feeding a single network from two or more generators or sources in parallel; Arrangements for feeding already energised networks from additional generators or sources in parallel
    • H02J3/40—Synchronisation of generators for connection to a network or to another generator
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—ELECTRIC POWER NETWORKS; 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 feeding a single network from two or more generators or sources in parallel; Arrangements for feeding already energised networks from additional generators or sources in parallel
    • H02J3/46—Controlling the sharing of generated power between the generators, sources or networks
    • H02J3/48—Controlling the sharing of active power
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of DC power input into DC power output
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of AC power input into DC power output; Conversion of DC power input into AC power output
    • H02M7/42—Conversion of DC power input into AC power output without possibility of reversal
    • H02M7/44—Conversion of DC power input into AC power output without possibility of reversal by static converters
    • H02M7/48—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/53—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M7/537—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters
    • H02M7/539—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters with automatic control of output wave form or frequency
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2101/00—Supply or distribution of decentralised, dispersed or local electric power generation
    • H02J2101/20—Dispersed power generation using renewable energy sources
    • H02J2101/22—Solar energy
    • H02J2101/24—Photovoltaics

Definitions

  • This disclosure relates to a power conversion device.
  • thermal power plants as a coordinating power are expected to be closed in the future because the power generation costs including management costs will increase as the amount of power generated by renewable energy increases.
  • Synchronous generators such as thermal power generation have a potential effect of suppressing the fluctuation of the system frequency (inertia force, synchronization force, etc.).
  • the closure of thermal power plants progresses, it becomes difficult to ensure the stability of the system.
  • Patent Document 1 discloses a control method for a static inverter and a control device in which a virtual synchronous generator control technique is implemented. Specifically, Patent Document 1 describes a control method for controlling a virtual synchronous generator during steady operation during grid connection.
  • the inverter unit described in Patent Document 1 is composed of a governor control unit, a mass point system calculation unit, and an AVR (Automatic Voltage Regulator) unit required for controlling a virtual synchronous generator.
  • the mass point system calculation unit uses the static inverter based on the difference information between the active power output from the static inverter and the command value (power target value) output from the energy management device (hereinafter referred to as EMS). Calculate the output angular frequency. Based on the calculated angular frequency, current value, and set voltage, the inverter unit controls so that the target AC voltage becomes the phase-advancing phase when the frequency of the power system drops.
  • the static inverter equipped with the virtual synchronous generator control function described in Patent Document 1 generates an AC voltage of an AC system and operates as a voltage source.
  • This static inverter has the angular frequency of the AC voltage of the AC system output from the static inverter (AC system) based on the difference between the output power target value notified by the EMS and the active power output by the static inverter. Calculate the frequency and phase of the AC voltage).
  • This static inverter is added to the output power target value notified by the EMS based on the difference between the frequency of the AC voltage of the AC system and the frequency target value (for example, 60 Hz) of the AC voltage of the AC system notified by the EMS. Generate an offset value.
  • this static inverter delivers more active power than the output power target value notified by the EMS. Output in the discharge direction).
  • the control for operating the static inverter as a voltage source will be referred to as voltage control.
  • the control of operating the static inverter as a current source in synchronization with the input AC voltage is referred to as current control.
  • the EMS manages the number of static inverters connected to the distribution system according to the power demand. For example, in a distribution system in which three static inverters are installed, if the power demand can be met by the output of one static inverter, three stationary inverters are considered in consideration of the efficiency of the power conversion device including the static inverter. It is better to supply all the power with one inverter than to share the power with the type inverter. However, when the demand power increases and it becomes difficult for one inverter to meet the electric charge demand, the EMS outputs an instruction to add another static inverter to the distribution system.
  • the static inverter which has been instructed to newly join the distribution system, detects the frequency, phase, and amplitude of the AC voltage of the AC system based on the AC voltage of the AC system of its own distribution system. Then, the static inverter generates a target value of the AC voltage of the AC system when performing voltage control using the measured frequency, phase, and amplitude, and outputs the electric power to the AC system.
  • the AC voltage target value is in a slow phase, so immediately after the start of voltage control, the AC system heads toward the static inverter. Power flows in. The flowing power changes depending on the phase difference.
  • the control circuit that controls the static inverter is often composed of a microcomputer.
  • the microcomputer samples the AC voltage of the AC system, the AC system current, and the like in synchronization with the carrier when performing PWM (Power Width Modulation) conversion, which is a reference when controlling the static inverter. More specifically, the microcomputer generates an interrupt signal based on the carrier signal, and calculates a command value based on the generated interrupt signal.
  • PWM Power Width Modulation
  • the sampling position of the AC voltage of the AC system changes depending on the timing at which the carrier interrupt is input.
  • an error in the time axis direction due to sampling also occurs.
  • errors in the linearity and amplitude directions of the voltage sensor also occur. Due to these errors, errors occur in the frequency, phase, and voltage amplitude of the output AC voltage of the newly input static inverter.
  • the static inverter sucks unnecessary power from the system (charging) at the time of new input. When this unnecessary power exceeds the power capacity of the static inverter that has already been turned on, the static inverter that has already been turned on stops due to overload.
  • An object of the present disclosure is to provide a power conversion device capable of suppressing the shutdown of a static inverter originally connected to an AC system when a stopped inverter is newly introduced into the AC system. That is.
  • the power conversion device of the present disclosure includes an inverter that converts power output from a distributed power source into AC power and outputs it to an AC system, an AC voltage measuring instrument that measures the AC voltage of the AC system, and an output of the AC voltage measuring instrument. Based on, an AC frequency detection circuit that detects the frequency and phase of the AC voltage of the AC system, and an inverter control circuit that generates an AC voltage target value when controlling the inverter and generates a command value to control the inverter as a voltage source. And.
  • the inverter control circuit sets the frequency of the AC voltage target value as the frequency of the AC voltage detected by the AC frequency detection circuit when the inverter is input to the AC system, and when the target value of the AC power is in the power running direction,
  • the phase of the AC voltage target value is controlled so that it is at least phase-advanced with respect to the AC voltage of the AC system.
  • the power conversion device of the present disclosure when a stopped inverter is newly introduced into the AC system, it is possible to prevent the stationary inverter originally connected to the AC system from stopping.
  • FIG. 1 It is a block diagram which shows the structure of the distribution system (AC system) to which the power conversion apparatus which concerns on Embodiment 1 is connected. It is a block diagram for further explaining the structure of some equipment including a distribution system storage battery 40 connected to the distribution system 24 shown in FIG. 1 and the distribution system 24. It is a block block diagram of the power conversion device 27 for mega solar shown in FIG. It is a block block diagram of the power conversion apparatus 41 for a power distribution system storage battery shown in FIG. It is a block diagram explaining the structure of the 1st control circuit 204 which controls the 1st DC / DC conversion circuit 203 of the power conversion apparatus 27 for mega solar shown in FIG.
  • FIG. 40 It is a block diagram explaining the structure of the inverter voltage control circuit 4095 shown in FIG. It is a block diagram explaining the structure of the virtual synchronous generator control circuit 4093 shown in FIG. It is a figure for demonstrating the operation of the target power generation circuit 40931. It is a figure for demonstrating the operation of the target frequency generation circuit 40934. It is a block diagram explaining the structure of the governor control circuit 40933 shown in FIG. It is a block diagram explaining the structure of the mass point system arithmetic circuit 40937 shown in FIG. It is a figure which shows the structure of the distribution system simplified for demonstrating the effect at the time of newly inputting the power conversion apparatus 41 for a distribution system storage battery.
  • (A) is an AC voltage waveform of the distribution system 24 at the connection point of the load 31 when the power conversion device 41b for the distribution system storage battery is turned on in a slow phase, and an AC system output by the power conversion device 41b for the distribution system storage battery. It is a figure which shows the AC voltage waveform.
  • (B) is a figure which shows the output current waveform of the power conversion apparatus 41b for a distribution system storage battery. Charge / discharge power (effective value) of the two power conversion devices 41a for the distribution system storage battery and the power conversion device 41b for the distribution system storage battery when the AC voltage phase of the newly introduced power conversion device 41b for the distribution system storage battery is slow. It is a figure which shows.
  • (A) is an AC voltage waveform of the distribution system 24 at the connection point of the load 31 when the power conversion device 41b for the distribution system storage battery is turned on in the phase-advancing phase, and an AC system output by the power conversion device 41b for the distribution system storage battery. It is a figure which shows the AC voltage waveform.
  • (B) is a figure which shows the output current waveform of the power conversion apparatus 41b for a distribution system storage battery. Charge / discharge power (effective value) of the two distribution system storage battery power conversion devices 41a and the distribution system storage battery power conversion device 41b when the AC voltage phase of the newly introduced power distribution system storage battery power conversion device 41b is phase-advanced. It is a figure which shows.
  • FIG. 5 is a flowchart showing a control procedure when a new power conversion device 41 for a power distribution system storage battery of the fourth control circuit 409 in the second embodiment is input.
  • FIGS. (A) to (C) are diagrams for explaining a method of detecting a zero cross point time (phase) of a slow phase phase. It is a figure which shows the charge / discharge power (effective value) of two power distribution system storage battery power conversion apparatus 41 when the AC voltage phase of the newly input distribution system storage battery power conversion apparatus 41 in Embodiment 2 is a slow phase. ..
  • an energy-creating device that uses renewable energy such as a solar cell, and a power converter that interconnects an energy storage device such as a storage battery by alternating current have the characteristics of a synchronous generator. Regarding virtual synchronous generator control to improve stability.
  • FIG. 1 is a block diagram showing a configuration of a power distribution system (AC system) to which the power conversion device according to the first embodiment is connected.
  • AC system power distribution system
  • a single-phase system will be described as an example for the sake of simplicity, but it may be applied to a three-phase system.
  • the distribution system 24 (24a to 24d) is connected to the substation 20, and the distribution system 24 is provided with a plurality of automatic voltage regulators 23 (23a to 23c) in series.
  • each automatic voltage regulator 23 is composed of an SVR, and hereinafter, the automatic voltage regulator 23 is referred to as an SVR 23.
  • the distribution system 24 includes a town 100 (town A100a, town B100b, town C100c, town D100d), a factory 101, a building 102, an apartment 103, a power conversion device 27 for mega solar, and a power conversion device 41 for a distribution system storage battery (hereinafter referred to as power conversion system 24). , Each of these may be referred to as a "customer").
  • a plurality of voltmeters 22 are connected to the distribution system 24.
  • the measurement result of the voltmeter 22 is transmitted to the power distribution automation system 21 (hereinafter, the power distribution automation system 21 is also referred to as DSO 21) at a predetermined cycle.
  • the tap position information of the SVR 23, the primary side voltage information, and the secondary side voltage information are also notified to the power distribution automation system 21.
  • the SVR 23 notifies the power distribution automation system 21 of the tap position information, the primary side, and the secondary side voltage information at a predetermined cycle, and also notifies the power distribution automation system 21 irregularly at the time of tap switching.
  • the DSO21 has a predetermined cycle for each customer (building 102, apartment 103, town 100, factory 101, mega solar power converter 27, synchronous generators 30a and 30b, and distribution system storage battery power converter 41a. , 41b, 41c), and collect information such as various measurement results.
  • a CEMS Common Energy Management System
  • a CEMS Common Energy Management System
  • a CEMS is installed in each customer from a smart meter (not shown) in a predetermined cycle (for example, a 30-minute cycle) in town A100a, town B100b, town C100c, and town D100d.
  • the power consumption of the consumer and the power generated by the energy-creating equipment are collected, and the collection result is notified to the DSO21.
  • the mega solar 26 is connected to the power conversion device 27 for the mega solar.
  • the distribution system storage batteries 40a, 40b, 40c are connected to the power conversion devices 41a, 41b, 41c for the distribution system storage battery.
  • FIG. 2 is a block diagram for further explaining the configuration of some devices including the distribution system storage battery 40 connected to the distribution system 24 shown in FIG. 1 and the distribution system 24.
  • a load 31 an impedance 29 of the distribution system, a distribution system storage battery 40, and a power conversion device 41 for the distribution system storage battery are connected to the distribution system 24.
  • Impedance 29 is represented in a centralized system for the sake of simplicity. In the first embodiment, it is assumed that the impedance 29 of the distribution system is composed of a reactor component and a resistance component.
  • FIG. 3 is a block configuration diagram of the mega solar power conversion device 27 shown in FIG.
  • the mega solar power converter 27 includes a voltmeter 201, a voltmeter 202, a first DC / DC conversion circuit 203, a first control circuit 204, a DC bus 205, a voltmeter 206, and a current.
  • a total of 207, a first DC / AC conversion circuit 208, a second control circuit 209, a voltmeter 210, a current meter 211, and a communication interface circuit 212 are provided.
  • the voltmeter 201 measures the first DC voltage output from the mega solar 26.
  • the ammeter 202 measures the direct current output from the mega solar 26.
  • the first DC / DC conversion circuit 203 converts the DC power of the first DC voltage output from the mega solar 26 into the DC power of the second DC voltage.
  • the first control circuit 204 controls the first DC / DC conversion circuit 203.
  • the DC bus 205 supplies the second DC voltage output from the first DC / DC conversion circuit 203 to the first DC / AC conversion circuit 208 through the DC bus 205.
  • the voltmeter 206 measures the second DC voltage of the DC bus 205.
  • the ammeter 207 measures the direct current output from the first DC / DC conversion circuit 203.
  • the first DC / AC conversion circuit 208 converts the DC power output from the first DC / DC conversion circuit 203 into AC power and outputs it to the distribution system 24.
  • the second control circuit 209 controls the first DC / AC conversion circuit 208.
  • the voltmeter 210 measures the AC voltage output from the first DC / AC conversion circuit 208.
  • the ammeter 211 measures the alternating current output from the first DC / AC conversion circuit 208.
  • the communication interface circuit 212 communicates with the DSO 21.
  • FIG. 4 is a block configuration diagram of the power conversion device 41 for the distribution system storage battery shown in FIG.
  • the power conversion device 41 for the distribution system storage battery includes a voltmeter 401, a current meter 402, a second DC / DC conversion circuit 403, a third control circuit 404, a DC bus 405, and a voltmeter 406. It includes a current meter 407, a second DC / AC conversion circuit 408, a fourth control circuit 409, a voltmeter 410, a current meter 411, and a communication interface circuit 412.
  • the voltmeter 401 measures the third DC voltage output from the distribution system storage battery 40.
  • the ammeter 402 measures the direct current output from the distribution system storage battery 40.
  • the second DC / DC conversion circuit 403 converts the DC power of the third DC voltage output from the distribution system storage battery 40 into the DC power of the fourth DC voltage.
  • the third control circuit 404 controls the second DC / DC conversion circuit 403.
  • the DC bus 405 supplies a fourth DC voltage output from the second DC / DC conversion circuit 403 to the second DC / AC conversion circuit 408.
  • the voltmeter 406 measures the fourth DC voltage of the DC bus 405.
  • the ammeter 407 measures the direct current output from the second DC / DC conversion circuit 403.
  • the second DC / AC conversion circuit 408 converts the DC power output from the second DC / DC conversion circuit 403 into AC power and outputs it to the distribution system 24.
  • the fourth control circuit 409 controls the second DC / AC conversion circuit 408.
  • the voltmeter 410 measures the AC voltage output from the second DC / AC conversion circuit 408.
  • the ammeter 411 measures the alternating current output from the second DC / AC conversion circuit 408.
  • the communication interface circuit 412 communicates between the power conversion device 41 for the distribution system storage battery and the DSO 21.
  • a known DC / DC converter configuration can be appropriately used.
  • a known inverter configuration can be appropriately used.
  • each of the first DC / AC conversion circuit 208 and the second DC / AC conversion circuit 408 "converts the power output from the distributed power supply into AC power and converts the AC power into an AC system.
  • the second control circuit 209 is an "inverter control circuit that generates a command value for controlling the inverter as a current source based on the input AC voltage”.
  • the fourth control circuit 409 corresponds to an embodiment of "an inverter control circuit that generates an AC voltage target value when controlling an inverter and generates a command value for controlling the inverter as a voltage source”.
  • FIG. 5 is a block diagram illustrating the configuration of the first control circuit 204 that controls the first DC / DC conversion circuit 203 of the mega solar power conversion device 27 shown in FIG.
  • the first control circuit 204 includes an MPPT (Maximum Power Point Tracking) control circuit 2041, a voltage control circuit 2042, a first switching circuit 2043, and a fifth control circuit 2044.
  • MPPT Maximum Power Point Tracking
  • the MPPT control circuit 2041 executes so-called maximum power point tracking control.
  • the MPPT control circuit 2041 searches for the maximum power point of the mega solar 26 based on the measured values of the voltmeter 201 and the ammeter 202 in order to extract the electric power generated from the mega solar 26 as much as possible.
  • the MPPT control circuit 2041 sets a control command value of the first DC / DC conversion circuit 203 for controlling the DC voltage measured by the voltmeter 201 so as to be a voltage corresponding to the maximum power point. Generate.
  • the voltage control circuit 2042 is a first DC / DC conversion circuit 203 for maintaining the DC voltage (second DC voltage) of the DC bus 205 at a predetermined voltage target value based on the measured value of the voltmeter 206. Generates the control command value of.
  • the fifth control circuit 2044 controls the MPPT control circuit 2041 and the voltage control circuit 2042 based on the status information of the first DC / DC conversion circuit 203 and the information of the second control circuit 209. It outputs the target value and manages the power generation status of the mega solar 26.
  • the fifth control circuit 2044 further outputs the control signal of the first switching circuit 2043.
  • the first switching circuit 2043 selects one of the output of the MPPT control circuit 2041 and the output of the voltage control circuit 2042 according to the control signal from the fifth control circuit 2044, and performs the first DC / DC conversion. It is output as a control command value of the circuit 203.
  • the first DC / DC conversion circuit 203 is controlled in the MPPT mode or the voltage control mode.
  • the first switching circuit 2043 outputs the control command value generated by the MPPT control circuit 2041 when the mode of the first DC / DC conversion circuit 203 is the MPPT mode.
  • the first switching circuit 2043 is controlled so as to output the control command value generated by the voltage control circuit 2042 when the mode of the first DC / DC conversion circuit 203 is the voltage control mode.
  • FIG. 6 is a block diagram illustrating the configuration of the second control circuit 209 that controls the first DC / AC conversion circuit 208 of the mega solar power conversion device 27 shown in FIG.
  • the second control circuit 209 includes a phase detection circuit 2091, a first sine wave generation circuit 2092, a current control circuit 2090, and a sixth control circuit 2097.
  • the current control circuit 2090 includes a subtractor 2093, a first PI control circuit 2094, a multiplier 2095, a subtractor 2096, a second PI control circuit 2098, and a first PWM conversion circuit 2099.
  • the current control circuit 2090 operates by the control method of a general power conversion device for photovoltaic power generation installed in a home. In this control method, the power conversion device is controlled to output power in synchronization with the AC voltage of the AC system.
  • the phase detection circuit 2091 detects the phase from the AC voltage waveform measured by the voltmeter 210. In the first embodiment, the phase detection circuit 2091 detects the zero cross point from the AC voltage waveform and also detects the frequency of the AC voltage from the detection result of the zero cross point. The phase detection circuit 2091 outputs the frequency of the AC voltage and the zero cross point information as phase information to the first sine wave generation circuit 2092.
  • the first sine wave generation circuit 2092 is a sine wave synchronized with the AC voltage waveform measured by the voltmeter 210 based on the amplitude of the AC voltage measured by the voltmeter 210 and the phase information detected by the phase detection circuit 2091. Occurs.
  • the current control circuit 2090 generates a control command value for controlling the first DC / DC conversion circuit 208 based on the DC voltage of the DC bus 205 output from the voltmeter 206.
  • the DC voltage of the DC bus 205 output from the voltmeter 206 is subtracted from the target value of the DC bus voltage output from the sixth control circuit 2097 by the subtractor 2093, and the subtraction result is the first PI control circuit 2094. Is entered in.
  • the DC voltage of the DC bus 205 is set to a predetermined value based on the control parameters (proportional gain and integration time) output from the sixth control circuit 2097 and the output of the subtractor 2093.
  • the voltage command value is output so that
  • the voltage command value output from the first PI control circuit 2094 is multiplied by the sine wave synchronized with the AC voltage waveform output from the first sine wave generation circuit 2092 by the multiplier 2095 to obtain a current.
  • the command value is generated.
  • the subtractor 2096 subtracts the current value of the AC system measured by the ammeter 211 from the current command value output from the multiplier 2095, and outputs the subtraction result to the second PI control circuit 2098.
  • the second PI control circuit 2098 is a current command so that the subtraction result output from the subtractor 2096 becomes zero based on the control parameters (proportional gain and integration time) output from the sixth control circuit 2097.
  • the value is output to the first PWM conversion circuit 2099.
  • the first PWM conversion circuit 2099 PWM-converts the current command value from the second PI control circuit 2098, generates a control command value, and outputs the control command value to the first DC / AC conversion circuit 208. ..
  • the sixth control circuit 2097 controls the current control circuit 2090.
  • the sixth control circuit 2097 is the first control circuit 204, the measurement result of the DC bus 205 output from the voltmeter 206 and the ammeter 207, and the measurement result of the AC system output from the voltmeter 210 and the ammeter 211.
  • the status information of the first DC / DC conversion circuit 203 output from is collected.
  • the sixth control circuit 2097 notifies the DSO21 and the like of the collected information through the communication interface circuit 212.
  • the control parameters of the first PI control circuit 2094 and the second PI control circuit 2098 are also notified from the sixth control circuit 2097. Furthermore, regarding the effective voltage of the AC system measured by the effective voltage measurement circuit of the AC system (not shown), or the active power measured by the active power measurement circuit and the reactive power measurement circuit of the AC system (not shown), and the active power information. Is also notified to the DSO 21 by the sixth control circuit 2097 via the communication interface circuit 212. The sixth control circuit 2097 also notifies the fifth control circuit 2044 of the measurement results of the effective voltage, active power, etc. of the AC system. For example, when the effective value of the AC voltage of the AC system exceeds a predetermined value, the fifth control circuit 2044 switches the control of the mega solar 26 from the MPPT mode to the voltage control mode to increase the AC voltage of the AC system. Suppress.
  • FIG. 7 is a block diagram illustrating the configuration of the third control circuit 404 that controls the second DC / DC conversion circuit 403 of the power conversion device 41 for the distribution system storage battery shown in FIG.
  • the third control circuit 404 includes a charge control circuit 4041, a discharge control circuit 4042, a second switching circuit 4043, and a seventh control circuit 4044.
  • the charge control circuit 4041 controls the second DC / DC conversion circuit 403 when performing charge control of the distribution system storage battery 40 based on the output of the ammeter 402, the output of the voltmeter 401, and the output of the voltmeter 406. Generate a command value.
  • the seventh control circuit 4044 outputs control parameters, control target values, and the like to the charge control circuit 4041 and the discharge control circuit 4042, and outputs the charge amount, charge current amount, discharge power amount, and the like of the distribution system storage battery 40. to manage.
  • the seventh control circuit 4044 outputs the control signal of the second switching circuit 4043.
  • the second switching circuit 4043 selects one of the output of the charge control circuit 4041 and the output of the discharge control circuit 4042 according to the control signal from the seventh control circuit 4044, and performs a second DC / DC conversion. It is output as a control command value of the circuit 403.
  • the second switching circuit 4043 outputs a control command value generated by the charge control circuit 4041 when the charge of the distribution system storage battery 40 is instructed, and discharge control when the discharge of the distribution system storage battery 40 is instructed.
  • the circuit 4042 is controlled to output the generated control command value.
  • FIG. 8 is a block diagram illustrating the configuration of the fourth control circuit 409 that controls the second DC / AC conversion circuit 408 of the power conversion device 41 for the distribution system storage battery shown in FIG.
  • the fourth control circuit 409 includes an AC frequency detection circuit 4091, an effective power calculation circuit 4092, a virtual synchronous generator control circuit 4093, an inverter current control circuit 4094, an inverter voltage control circuit 4095, and a third control circuit.
  • the switching circuit 4096 is provided.
  • the AC frequency detection circuit 4091 detects the phase from the AC voltage waveform measured by the voltmeter 410.
  • the AC frequency detection circuit 4091 detects the zero cross point from the AC voltage waveform, and detects the frequency from the time interval of the detected zero cross point.
  • the frequency detection method of the AC voltage is not limited to the method using the detection result of the zero cross point.
  • the effective power calculation circuit 4092 calculates the effective power output from the second DC / AC conversion circuit 408 (inverter) from the AC voltage information measured by the voltmeter 410 and the current meter 411 and the AC current information.
  • the effective power calculation circuit 4092 integrates the power for one cycle of the AC voltage waveform by using the zero cross point detection information output from the AC frequency detection circuit 4091 and the AC frequency information, and the effective power. Is calculated.
  • the method for calculating the effective power is not limited to the above method. For example, when the AC system is a three-phase AC, the effective power may be calculated by using DQ conversion or the like.
  • the virtual synchronous generator control circuit 4093 is a second DC / DC conversion circuit 408 (stationary) based on the frequency information of the AC voltage output from the AC frequency detection circuit 4091 and the effective power calculation circuit 4092 and the effective power information.
  • the type inverter executes the virtual synchronous generator control so as to have the inertial force, the synchronous force, and the braking force of the synchronous generator.
  • the virtual synchronous generator control technology will be briefly described. Synchronous generators represented by thermal power generation have a function to adjust the output power according to the frequency (governor function), a function to maintain angular velocity (inertial force), and a function to synchronize with the AC voltage of the AC system (synchronization).
  • the static inverter by controlling the transient response of the static inverter, the static inverter is made to simulate the function of the synchronous generator.
  • the static inverter simulates three functions: a governor function, a function simulating a mass point system model (dynamic characteristics of a rotating machine) based on a sway equation, and an AVR function.
  • the governor function and the function simulating the mass point system model based on the sway equation are implemented. Since the AVR function of the synchronous generator is a function controlled mainly based on the output voltage command notified from the host system (DSO21 in the first embodiment) or the invalid power command value, the first embodiment 1 Will not be implemented.
  • the governor function and the function simulating the mass point system model based on the sway equation will be specifically described.
  • the governor in a power plant has a function of controlling the output power of a generator by controlling the output of a gas turbine or steam turbine of thermal power generation or nuclear power generation, and a guide vane of a water turbine of hydroelectric power generation.
  • the governor In the AC power system, when the demand exceeds the supply, the frequency of the AC voltage of the AC system decreases.
  • the governor In a thermal power generator or a hydroelectric generator capable of output control, the governor has a droop characteristic and is controlled to increase the generated power when the frequency decreases.
  • the governor when the supply exceeds the demand, the frequency of the AC voltage of the AC system rises.
  • the governor has a droop characteristic and is controlled to reduce the generated power as the frequency increases.
  • FIG. 9 is a diagram schematically showing the governor function.
  • the valve 999 that regulates the inflow of energy moves to the right.
  • the energy supplied to the synchronous generator is reduced.
  • the valve 999 that regulates the inflow of energy moves to the left.
  • the energy supplied to the synchronous generator increases.
  • the synchronous generator can independently control the energy output from the synchronous generator by the frequency of the AC voltage of the AC system at the end of the synchronous generator (the angular speed of the synchronous generator).
  • the synchronous generator has a generator rotor 998 having an inertial constant M as shown in FIG.
  • the synchronous generator converts the rotational energy stored in the generator rotor 998 into electric power and outputs it to the AC system. At that time, the angular velocity (rotational speed) of the generator rotor 998 decreases.
  • Equation (2) is a sway equation (energy P divided by angular velocity ⁇ and converted to torque T) simulating a mass system model (generator rotor 998).
  • Dg indicates a braking coefficient
  • M indicates the above-mentioned inertial constant.
  • Tin-Tout M ⁇ d ⁇ / dt + Dg ⁇ ⁇ ⁇ ⁇ ⁇ (2)
  • the static inverter has the inertial force of the synchronous generator. , Synchronizing force, and braking force are simulated.
  • the inverter current control circuit 4094 generates a control command value when the second DC / AC conversion circuit 408 is controlled by current control.
  • the circuit configuration and operation of the inverter current control circuit 4094 are the same as those of the current control circuit 2090 in FIG. The only difference between the inverter current control circuit 4094 and the current control circuit 2090 in FIG. 6 is the control parameters used.
  • the inverter voltage control circuit 4095 sets a control command value when the second DC / AC conversion circuit 408 is controlled by voltage control (a control method for outputting the AC voltage of the AC system from the second DC / AC conversion circuit 408). Generate.
  • the third switching circuit 4096 switches between the control command value from the inverter current control circuit 4094 and the control command value from the inverter voltage control circuit 4095 based on the output of the eighth control circuit 4097.
  • the eighth control circuit 4097 is a measurement result regarding the DC bus 405 output from the voltmeter 406 and the ammeter 407, a measurement result regarding the AC system output from the voltmeter 410 and the ammeter 411, and a third control circuit 404.
  • the status information of the second DC / DC conversion circuit 403 output from is collected.
  • the eighth control circuit 4097 notifies the DSO21 and the like of the collected information via the communication interface circuit 412.
  • the eighth control circuit 4097 also notifies various control parameters of the virtual synchronous generator control circuit 4093, the inverter current control circuit 4094, and the inverter voltage control circuit 4095 described above. Further, the effective voltage of the AC system measured by the effective voltmeter circuit of the AC system (not shown), or the active power and the active power information measured by the effective and ineffective power measurement circuit of the AC system (not shown) are also obtained. The DSO 21 is notified via the communication interface circuit 412. The measurement results of the effective voltage, active power, etc. of the AC system are also notified to the seventh control circuit 4044.
  • FIG. 10 is a block diagram illustrating the configuration of the AC frequency detection circuit 4091 shown in FIG.
  • the AC frequency detection circuit 4091 includes a phase detection circuit 40910, a frequency detection circuit 40911, and a second sine wave generation circuit 40912.
  • the phase detection circuit 40910 detects the zero cross point from the voltage waveform of the AC system output from the voltmeter 410.
  • the phase detection method in the phase detection circuit 40910 is not limited to zero cross point detection.
  • the zero cross point detection error (mainly offset error) in the voltmeter 410
  • the amplitude detection error (mainly linearity error) in the voltmeter 410
  • the sampling cycle when sampling the grid AC voltage waveform. Error etc. occurs.
  • the error of the sampling cycle occurs due to the variation in the time from the carrier interrupt to the actual sampling when sampling is performed using a microcomputer or the like.
  • the frequency detection circuit 40911 detects the frequency of the AC voltage of the AC system from the period of the zero cross point output from the phase detection circuit 40910.
  • the frequency detection method of the AC voltage of the AC system is not limited to the method of detecting from the period of the zero cross point.
  • the second sine wave generation circuit 40912 is based on the zero cross point detection result in the phase detection circuit 40910, the frequency detection result in the frequency detection circuit 40911, and the AC voltage amplitude of the AC system output from the DSO21. Generates a sine wave synchronized with.
  • the AC frequency detection circuit 4091 outputs the zero cross point detection result, the frequency detection result, and the sine wave information.
  • FIG. 11 is a block diagram illustrating the configuration of the inverter voltage control circuit 4095 shown in FIG.
  • the inverter voltage control circuit 4095 includes a third sine wave generation circuit 40951, a subtractor 40952, a third PI control circuit 40953, and a second PWM conversion circuit 40954.
  • the inverter voltage control circuit 4095 is based on frequency information and phase information output from the virtual synchronous generator control circuit 4093, which will be described in detail later, and AC voltage amplitude information of the AC system output from the eighth control circuit 4097. , Outputs a control command value for controlling the second DC / AC conversion circuit 408.
  • the sine wave information from the AC frequency detection circuit 4091 is input to the third sine wave generation circuit 40951.
  • the sine wave information includes frequency information, phase information, and amplitude information.
  • the amplitude information may not be included in the sine wave information. This is because QV control is not performed in the virtual synchronous generator control circuit 4093.
  • the third sine wave generation circuit 40951 generates a target value of the AC voltage of the AC system output from the second DC / AC conversion circuit 408 based on the input frequency information, phase information, and amplitude information.
  • the subtractor 40952 subtracts the AC voltage measured by the voltmeter 410 from the output of the third sine wave generation circuit 40951, and outputs the subtraction result to the third PI control circuit 40953.
  • the third PI control circuit 40953 generates a voltage command value by PI control so that the input subtraction result becomes zero, and outputs the voltage command value to the second PWM conversion circuit 40954.
  • the control parameters (control gain and integration time) of the third PI control circuit are output from the eighth control circuit 4097.
  • the second PWM conversion circuit 40954 PWM-converts the voltage command value output from the third PI control circuit 40953, and outputs the control command value to the third switching circuit 4096.
  • FIG. 12 is a block diagram illustrating the configuration of the virtual synchronous generator control circuit 4093 shown in FIG.
  • the virtual synchronous generator control circuit 4093 includes a target power generation circuit 40931, a subtractor 40932, a governor control circuit 40933, a target frequency generation circuit 40934, an adder 40935, a subtractor 40936, and a mass system arithmetic circuit. 40937 is provided.
  • the target power generation circuit 40931 generates the power target value of the virtual synchronous generator control circuit 4093 (the target value of the AC power output by the second DC / AC conversion circuit 408 which is an inverter).
  • the power target value is input to the mass point system calculation circuit 40937 via the adder 40935 and the subtractor 40936.
  • the target power generation circuit 40931 outputs the charge / discharge power from the distribution system storage battery 40 based on the power command value (power target value) output from the DSO 21.
  • the target power generation circuit 40931 outputs the power command value from the DSO 21.
  • the embodiment is implemented in order to minimize the fluctuation of the system immediately after the input.
  • the target power generation circuit 40931 outputs the power command value as zero immediately after the power is turned on, and then changes the power command value (power target value) Pre specified by the DSO 21 over a predetermined time.
  • the inverter (second DC / AC conversion circuit 408) of the power conversion device 41 for the distribution system storage battery is input to the AC system, and the power conversion device 41 for the distribution system storage battery is input to the system. , And may be described as interconnected.
  • FIG. 13 is a diagram for explaining the operation of the target power generation circuit 40931. With reference to FIG. 13, the operation of the target power generation circuit 40931 when the power conversion device 41 for the distribution system storage battery is newly input to the system will be described.
  • the target power generation circuit 40931 outputs zero. This is because when the newly input power conversion device 41 for the distribution system storage battery that is not charged / discharged is controlled to output the power target value Pref immediately after the input, there are the following problems. Power is supplied in balance with the load by the power generation equipment that has already been connected to the grid to supply power. Even if a new power conversion device 41 for the distribution system storage battery is input there by voltage control, no power is immediately output from the new power conversion device 41 for the distribution system storage battery. Therefore, the virtual synchronous generator control circuit 4093 determines that the power consumption of the load is small, and controls so as to raise the frequency of the AC voltage of the output AC system. As a result, unnecessary disturbance is added to the AC system from the power conversion device 41 for the storage battery of the distribution system newly introduced.
  • the target power generation circuit 40931 changes the power target value from Pref_b to Pref_a. You may receive such a command.
  • the new input information of the power conversion device 41 for the distribution system storage battery is also input to the target power generation circuit 40931.
  • the target power generation circuit 40931 sets the power target value to zero immediately after the power conversion device 41 for the distribution system storage battery to be newly input. After confirming the convergence of the system disturbance, the power target value is gradually increased from zero to Pref (for example, at a constant rate of change) in a predetermined time.
  • the power conversion device 41 for the distribution system storage battery which has already been connected to the grid, has a power target value (Pref_b) before the new power input until the system disturbance immediately after the new power input converges. After the system disturbance has converged, the power target value is gradually reduced (for example, at a constant rate of change) from Pref_b to Pref_a in a predetermined time as shown by the alternate long and short dash line in FIG.
  • the change of the power target value is controlled so as to be performed after the convergence of the disturbance of the AC voltage of the AC system is detected, but the present invention is not limited to this.
  • the same effect can be obtained by configuring the power target value to be changed after a predetermined time has elapsed after receiving the new input command from the DSO 21.
  • the target power generation circuit 40931 when the target power generation circuit 40931 receives a command to change the power target value from Pref_b to Pref_a, the target power generation circuit 40931 maintains the current power target value without switching the power target value for a predetermined time. If a large system disturbance occurs within that time, the target power generation circuit 40931 determines that a new power conversion device 41 for the distribution system storage battery has been turned on, and waits for switching of the power target value until the system disturbance converges. do. After that, the target power generation circuit 40931 controls the power target value as described above. As a result, the same effect can be obtained without exchanging new additional information from the DSO21.
  • the target frequency generation circuit 40934 generates the frequency (frequency target value) of the target AC voltage of the virtual synchronous generator control circuit 4093.
  • the frequency of the target AC voltage is input to the governor control circuit 40933 as a reference AC voltage frequency via the subtractor 40923.
  • FIG. 14 is a diagram for explaining the operation of the target frequency generation circuit 40934.
  • the target value of the frequency of the AC voltage of the AC system is fixed (for example, 50 Hz or 60 Hz). Therefore, in the first embodiment, the target frequency generation circuit 40934 determines the frequency of the AC voltage of the AC system detected by the frequency detection circuit 40911 immediately before the new input of the frequency target value of the power conversion device 41 for the distribution system storage battery to be newly input. Frequency), and the value is maintained until the disturbance immediately after the new input converges (see the solid line in FIG. 14).
  • the target frequency generation circuit 40934 gradually (for example, 60 Hz or 50 Hz) adjusts the frequency target value from the Fmesure to the frequency of the AC voltage of the predetermined AC system over a predetermined time (for example, 60 Hz or 50 Hz). , Constant rate of change).
  • the frequency target value is controlled by the system frequency (for example, 60 Hz or 50 Hz) and does not change significantly. Therefore, the target frequency generation circuit 40934 sets the frequency target value of the power conversion device 41 for the distribution system storage battery, which was originally connected to the system, to the frequency target value output from the eighth control circuit 4097.
  • the target power generation circuit 40931 when the control of the frequency of the AC voltage of the AC system output by the power conversion device 41 for the distribution system storage battery is started immediately after the new power is input, the system is already in the system. Unnecessary disturbance will be given to the state where the power is supplied in a balanced manner with the load by the power generation equipment that has been interconnected and supplied the power. Therefore, the target frequency generation circuit 40934 can be controlled without giving unnecessary disturbance to the AC system by setting the frequency target value to the frequency (Fmesure) of the detected AC voltage of the AC system immediately after the new input.
  • the subtractor 40923 subtracts the output of the target frequency generation circuit 40934 from the actual measurement result of the frequency output from the frequency detection circuit 40911.
  • the output of the subtractor 40923 is input to the governor control circuit 40933.
  • the governor control circuit 40933 is based on the difference between at least the reference AC voltage frequency (frequency target value) output by the target frequency generation circuit 40934 and the AC voltage frequency (measured frequency) output by the AC frequency detection circuit 4091. , The offset to be added to the target value of the AC power output from the inverter output by the target power generation circuit 40931 is output.
  • the adder 40935 generates the control power target value of the mass point system calculation circuit 40937 by adding the offset value output from the governor control circuit 40933 and the power target value output from the target power generation circuit 40931.
  • the subtractor 40936 subtracts the control power target value output from the adder 40935 from the effective power output from the effective power calculation circuit 4092.
  • the output of the subtractor 40936 is input to the mass point system arithmetic circuit 40937.
  • the quality point system calculation circuit 40937 takes the difference (output of the subtractor 40936) between the sum of the offset output from the adder 40935 and the target value of the AC power value and the output of the effective power calculation circuit 4092 as an input, and makes a difference (the output of the subtractor 40936).
  • the frequency and phase of the AC voltage of the AC system output from the inverter of the power conversion device 41 for the distribution system storage battery so that the output of the subtractor 40936) becomes zero are calculated.
  • the mass point system calculation circuit 40937 has an inertial force simulating unit that simulates the inertial force of the synchronous generator and a braking force simulating unit that simulates the braking force.
  • the quality point system calculation circuit 40937 sets the value of the inertial constant given to the inertial force simulation unit at least for a predetermined time immediately after the input, or the effective power output from the inverter within a predetermined range. Until it goes inside, set it to a value larger than the value of the inertial constant during normal operation.
  • the quality point system calculation circuit 40937 informs at least the value of the inertial constant given to the inertial force simulation unit regarding the new input of the other power conversion device by the communication interface circuit 412. Is set to a value larger than the value of the inertial constant during normal operation until a predetermined time after reception or until the effective power output from the inverter falls within a predetermined range.
  • the details of the mass point system arithmetic circuit 40937 will be described later.
  • FIG. 15 is a block diagram illustrating the configuration of the governor control circuit 40933 shown in FIG.
  • the governor control circuit 40933 includes a multiplier 409331, a first-order lag model (denoted as 1 / (1 + s ⁇ Tg) in the figure) 409332, and a limiter circuit 409333.
  • the multiplier 409331 multiplies the output of the subtractor 40932 with the proportional gain (denoted as -1 / Kgd in the figure) output from the eighth control circuit 4097.
  • the output of the multiplier 409331 is output to the first-order lag model 409332.
  • the first-order lag model 409332 implements the first-order lag model (1 / (1 + s ⁇ Tg)) as shown in FIG.
  • the output of the first-order lag model 409332 is output after being subjected to limiter processing by the limiter circuit 409333.
  • the output of the limiter circuit 409333 is sent to the adder 40935 as an offset value.
  • FIG. 16 is a block diagram illustrating the configuration of the mass point system arithmetic circuit 40937 shown in FIG.
  • the quality point system arithmetic circuit 40937 includes a subtractor 409371, an integrator (denoted as 1 / (M ⁇ s) in the figure) 409372, a multiplier 409373, a divider 409374, an adder 409375, and a phase.
  • a calculation circuit 409376 is provided.
  • the subtractor 409371 subtracts the output of the multiplier 409373 from the output of the subtractor 40936 (the result of subtraction between the actually measured effective power and the power target value).
  • the subtraction result is input to the integrator 409372.
  • the integrator 409372 integrates the output of the subtractor 409371 to obtain the target angular velocity of the generator rotor 998 shown in FIG. 9 (2 ⁇ ⁇ ⁇ 60 Hz: the frequency target value is 60 Hz in the first embodiment). A difference value ( ⁇ ) from the angular velocity of the generator rotor 998 is generated. The output of the integrator 409372 is input to the multiplier 409373.
  • the multiplier 409373 multiplies the output of the integrator 409372 by the braking coefficient Dg output from the eighth control circuit 4097.
  • the mass system arithmetic circuit 40937 simulates the braking force of the synchronous generator in the control of the second DC / AC conversion circuit 408.
  • the output ( ⁇ ) of the integrator 409372 is divided by the divider 409374 by 2 ⁇ ⁇ and converted into frequency difference information ( ⁇ f).
  • the adder 409375 outputs the frequency (rotation frequency) of the generator rotor 998 obtained by adding the frequency difference information ( ⁇ f) and the frequency target value (60 Hz) to the inverter voltage control circuit 4095 as the voltage control phase target value. do.
  • the output of the adder 409375 is input to the phase calculation circuit 409376.
  • the phase calculation circuit 409376 calculates the phase of the generator rotor 998 based on the output of the adder 409375 and the information from the eighth control circuit 4097, and sets the voltage control phase target value as the AC frequency detection circuit 4091.
  • the voltage is output to the inverter voltage control circuit 4095 via the second sine wave generation circuit 40912.
  • FIG. 17 is a diagram showing a simplified configuration of the distribution system for explaining the effect of newly inputting the power conversion device 41 for the distribution system storage battery.
  • the power conversion device 41a for the distribution system storage battery is connected to the AC system and supplies power to the load 31 via the impedance 29a.
  • the impedance 29 of the distribution system 24 is actually a resistance component and a capacitance component, but in the first embodiment, only the reactor component is used for the sake of simplicity.
  • the power conversion device 41b for the distribution system storage battery to be newly input is connected to the load 31 via the impedance 29b.
  • the operation when the DSO 21 instructs the power conversion device 41b for the distribution system storage battery to connect with the Pref as the power target value will be described.
  • the power conversion device 41a for the distribution system storage battery is also notified that the power conversion device 41b for the distribution system storage battery is newly input and that the power target value is switched from Pref_b to Pref_a.
  • the fourth control circuit 409 receives the new input instruction via the communication interface circuit 412, the fourth control circuit 409 outputs the start instruction of the second DC / DC conversion circuit 403 to the third control circuit 404, and also outputs the start instruction of the second DC / DC conversion circuit 403.
  • the DC / AC conversion circuit 408 of the above is activated.
  • a relay (not shown) or the like is turned on, the DC bus 405 is boosted to a predetermined voltage, and then the output of the second DC / AC conversion circuit 408 is connected to the AC system. do.
  • the eighth control circuit 4097 in the fourth control circuit 409 starts control for new input. do.
  • the third control circuit 404 also starts control for new input.
  • the AC frequency detection circuit 4091 When the control for new input is started in the fourth control circuit 409, the AC frequency detection circuit 4091 first detects the frequency and phase of the AC voltage of the AC system based on the output of the voltmeter 410. .. At this time, since power (current) is not output from the power conversion device 41b for the distribution system storage battery, the grid interconnection points of the power conversion device 41b for the distribution system storage battery (the power conversion device 41b for the distribution system storage battery and the impedance 29b) The AC voltage waveform at the point in between) becomes equal to the voltage waveform of the AC system input to the load 31.
  • the power conversion device 41b for the distribution system storage battery can be newly introduced at the frequency and phase of the AC voltage of the AC system at the grid interconnection point of the power conversion device 41b for the distribution system storage battery, the power conversion device 41b for the distribution system storage battery can be newly introduced without disturbing the AC system.
  • the power conversion device 41b for the distribution system storage battery can be turned on.
  • the measurement result of the voltmeter 410 includes an error.
  • the measurement result of the voltmeter 410 includes an offset error of the voltmeter 410, an error due to linearity, and the like.
  • the offset error is, for example, when the effective voltage is -5V with respect to 200V, and the zero cross point detected by the AC frequency detection circuit 4091.
  • the AC voltage of the AC system is generated based on the information, the AC voltage of the AC system output by the power conversion device 41b for the distribution system storage battery becomes a slow phase with respect to the AC voltage of the AC system supplied to the load 31.
  • FIG. 18 is a diagram showing the relationship between the AC voltage and the output AC current when the voltage phase of the AC system of the newly introduced power converter 41b for the distribution system storage battery is slow.
  • FIG. 19 shows the charge / discharge power of the two distribution system storage battery power conversion devices 41a and the distribution system storage battery power conversion device 41b when the AC voltage phase of the newly input distribution system storage battery power conversion device 41b is slow. It is a figure which shows (effective value).
  • the time axis scales of FIGS. 18 and 19 are different.
  • the horizontal axis of FIG. 18 is on the order of ms
  • the horizontal axis of FIG. 19 is on the order of seconds (s).
  • FIG. 18A shows the AC voltage waveform of the distribution system 24 at the connection point of the load 31 when the power conversion device 41b for the distribution system storage battery is turned on in a slow phase, and the AC output by the power conversion device 41b for the distribution system storage battery. It is a figure which shows the AC voltage waveform of a system.
  • FIG. 18B is a diagram showing an output current waveform of the power conversion device 41b for the distribution system storage battery.
  • FIG. 19 shows the temporal transition of the effective power output from the power conversion device 41a for the distribution system storage battery and the power conversion device 41b for the distribution system storage battery. As shown in FIG. 19, it can be seen that the power conversion device 41a for the distribution system storage battery covers the charging power of the power conversion device 41b for the distribution system storage battery with its own discharge power.
  • the DSO 21 activates the power conversion device 41b for the distribution system storage battery when it is predicted that the power supplied to the load 31 by the power conversion device 41a for the distribution system storage battery will be insufficient.
  • the charge / discharge power exceeds 90% of the rated capacity of the power conversion device 41a for the distribution system storage battery, it is controlled to newly add the power conversion device 41b for the distribution system storage battery.
  • the rated capacity of the power conversion device 41a for the distribution system storage battery may be exceeded as shown in FIG.
  • the power conversion device 41a for the distribution system storage battery may stop due to an overload, and the power supply to the distribution system 24 may stop.
  • the power charged by the power conversion device 41b for the distribution system storage battery is the difference in voltage phase (the magnitude of the slow phase phase) of the AC voltage waveform of the AC system at the grid interconnection point between the power conversion device 41b for the distribution system storage battery and the load 31. ). Specifically, the larger the phase difference, the larger the charging power.
  • FIG. 20 is a diagram showing the relationship between the AC voltage and the output AC current when the voltage phase of the AC system of the newly introduced power converter 41b for the distribution system storage battery is phase-advanced.
  • FIG. 21 shows the charge / discharge power of the two distribution system storage battery power conversion devices 41a and the distribution system storage battery power conversion device 41b when the AC voltage phase of the newly input distribution system storage battery power conversion device 41b is phase-advancing. It is a figure which shows (effective value).
  • the time axis scales of FIGS. 20 and 21 are different.
  • the horizontal axis of FIG. 20 is on the order of ms
  • the horizontal axis of FIG. 21 is on the order of seconds (s).
  • FIG. 20A shows the AC voltage waveform of the distribution system 24 at the connection point of the load 31 when the power conversion device 41b for the distribution system storage battery is turned on in the phase-advancing phase, and the AC output by the power conversion device 41b for the distribution system storage battery. It is a figure which shows the AC voltage waveform of a system.
  • FIG. 20B is a diagram showing an output current waveform of the power conversion device 41b for a distribution system storage battery. As shown in FIG. 20A, since the phase of the AC voltage of the AC system output by the power conversion device 41b for the distribution system storage battery is phase-advancing, the current flowing through the impedance 29b (the power conversion device 41b for the distribution system storage battery outputs). The current to be generated) is as shown in FIG. 20 (b).
  • the power conversion device 41b for the distribution system storage battery when the power conversion device 41b for the distribution system storage battery is newly introduced in the phase-advancing phase, the power flows in the direction of discharging the power (power running direction) to the power conversion device 41b for the distribution system storage battery as shown in FIG. 20 (b).
  • the fourth control circuit 409 sets the frequency of the AC voltage target value to the AC frequency when the second DC / AC conversion circuit 408 (inverter) is input to the AC system.
  • the frequency of the AC voltage detected by the detection circuit 4091 is used, and when the target value of the AC power is in the power running direction, the phase of the AC voltage target value is controlled so as to be at least phase-advanced with respect to the AC voltage of the AC system. do.
  • FIG. 21 shows the temporal transition of the effective power output from the power conversion device 41a for the distribution system storage battery and the power conversion device 41b for the distribution system storage battery. As shown in FIG. 21, it can be seen that the power conversion device 41a for the distribution system storage battery and the discharge power of the power conversion device 41b for the distribution system storage battery are combined and supplied to the load 31.
  • the power conversion device 41a for the distribution system storage battery and the power conversion device 41b for the distribution system storage battery share the power supply to the load 31, so that it occurs when a new power is input in a slow phase. There is no problem such as stopping due to overload.
  • the power discharged by the power conversion device 41b for the distribution system storage battery is the phase difference between the phase of the voltage of the power conversion device 41b for the distribution system storage battery and the phase of the AC voltage of the AC system at the grid interconnection point of the load 31. It depends on (the magnitude of the phase advance phase). Specifically, the larger the phase difference, the larger the discharge power.
  • the newly input power conversion device outputs the power in the power running direction (discharge direction), so that the voltage before the input It is possible to prevent the power conversion device operating as a source from stopping due to an overload.
  • the power conversion device connected to the grid is operating in the charging direction (charging the surplus power)
  • the power conversion device is newly input in the slow phase.
  • the newly input power conversion device operates in the regeneration direction (charging direction)
  • the new input in the slow phase will be described later.
  • the distribution system has been described as an example, but the present invention is not limited to this, and the same effect can be obtained even if it is applied to the power transmission system. Furthermore, it goes without saying that the same effect can be obtained even when connected to a self-employed line. Further, the same effect can be obtained even with an independent system such as a microgrid.
  • the specific operation of the power conversion device according to the first embodiment will be described with reference to FIGS. 1 to 26.
  • the power distribution system to which the power conversion device according to the first embodiment is connected will be described with reference to FIG. 1 again.
  • the distribution system 24 of the substation 20 and the power conversion device 27 for mega solar or the power conversion device 41 for the distribution system storage battery, Town D100d).
  • Three SVRs 23 are connected in series between them.
  • a power conversion device 41a for a distribution system storage battery is installed near the power conversion device 27 for mega solar.
  • the power conversion device 41a for the distribution system storage battery operates as a voltage source.
  • A100a, town B100b, town C100c, town D100d, factory 101, building 102, and condominium 103 are loads.
  • the load is supplied with power supplied from the substation 20, power generated by the mega solar 26, and power supplied from the distribution system storage battery 40a.
  • a distribution system storage battery 40c and a power conversion device 41c for the distribution system storage battery are arranged near the substation 20.
  • a distribution system storage battery 40b and a power conversion device 41b for the distribution system storage battery are arranged near the town B100b.
  • a synchronous generator 30a is arranged in the factory 101.
  • a synchronous generator 30b is arranged in the building 102 for emergency use.
  • the distribution system 24 is supported by the power supplied from the substation 20, the power generated by the mega solar 26 (the power conversion device 27 for the mega solar operates from the current source), and the discharge power output from the distribution system storage battery 40a.
  • the operation when a new distribution system storage battery 40b is newly added to the existing system will be described.
  • FIG. 22 is a flowchart showing the operation of the DSO 21 when a new power conversion device 41b for a distribution system storage battery is newly introduced into the distribution system.
  • step S101 the DSO 21 confirms whether the current time is the collection time of various measurement results.
  • the DSO21 confirms whether the current time is the collection time of various measurement data, and if it is not the collection time, waits until the current time becomes the collection time.
  • step S102 in the first embodiment, the DSO 21 has the instrumentation information of the substation 20, the measurement information of the voltmeter 22, the information of the SVR 23, the measurement information of the power conversion device 27 for mega solar (power generation, etc.) in a 1-minute cycle. ), Measurement information (charge / discharge power, SOC (State Of Charge), status information, etc.) of the power conversion device 41 for the distribution system storage battery is collected.
  • step S103 the DSO 21 reviews the operation plan of each distribution system storage battery 40.
  • step S104 the DSO 21 determines whether or not it is necessary to newly add the distribution system storage battery 40. Specifically, the DSO21 determines from the collected data that it needs to be added when the current distribution system storage battery 40a cannot cover the power. The case where the current distribution system storage battery 40a cannot cover the power is when the current power distribution system storage battery power conversion device 41a is operating at 90% or more of the rated capacity, or when the SOC is less than 10%. be.
  • step S105 If it is determined that the addition is necessary, the process proceeds to step S105, and if it is not determined that the addition is necessary, the process proceeds to step S106.
  • step S105 the DSO 21 notifies the power conversion device 41b for the distribution system storage battery to be newly added of the new entry request (instruction) and the power target value Pref. After that, the process proceeds to step S108.
  • step S106 the DSO 21 determines whether or not to disconnect the distribution system storage battery 40. Specifically, in the DSO 21, the power supplied to the distribution system 24 is sufficiently supplied, and even if the distribution system storage battery 40a is disconnected, the distribution system 24 is not affected, or the SOC of the distribution system storage battery 40 is increased. It is determined that the power conversion device 41 for the distribution system storage battery is disconnected when the value is equal to or less than the predetermined value (when there is a risk of over-discharging). When it is determined that the distribution system storage battery 40 is disconnected, the process proceeds to step S107. If it is not determined that the distribution system storage battery 40 is disconnected, the process returns to step 101.
  • step S107 the DSO 21 notifies the power conversion device 41 for the distribution system storage battery to be disconnected of the disconnection instruction. After that, the process proceeds to step S108.
  • step S108 the DSO 21 notifies the power conversion device 41 for the distribution system storage battery that is not added or disconnected that another power conversion device 41 for the distribution system storage battery is newly input or disconnected, and is new.
  • the additional power target value Prefa or the power target value after disconnection is notified to all the power conversion devices 41 for the distribution system storage battery connected to the system.
  • FIG. 23 is a flowchart showing the operation procedure of the power conversion device 41a for the distribution system storage battery which is connected to the system.
  • the power conversion device 41a for the distribution system storage battery collects various measurement data. Specifically, the power conversion device 41a for the distribution system storage battery collects the measured voltages of the voltmeters 401, 406, and 410. Since the measurement result of the voltmeter 410 is an AC voltage, the fourth control circuit 409 calculates the effective voltage and uses it as the measured voltage. The power conversion device 41a for the distribution system storage battery collects the measured currents of the ammeters 402, 407, and 411. Since the measurement result of the ammeter 411 is an alternating current, the fourth control circuit 409 calculates the effective current and uses it as the measured current. The power conversion device 41a for the distribution system storage battery collects status information (SOC, etc.) of the distribution system storage battery 40a.
  • SOC status information
  • step S122 when the communication interface circuit 412 receives the data from DSO21, the process proceeds to step S123. If the communication interface circuit 412 does not receive the data from the DSO 21, the process of step S121 continues.
  • step S123 the fourth control circuit 409 in the power conversion device 41a for the distribution system storage battery determines whether or not the received data is a data transmission request. When it is determined that the received data is a data transmission request, the process proceeds to step S124. If it is determined that the received data is not a data transmission request, the process proceeds to step S125.
  • step S124 the fourth control circuit 409 transmits the measurement result to the DSO 21 via the communication interface circuit 412. After that, the process returns to step S121.
  • step S125 the fourth control circuit 409 determines whether or not a disconnection request from the DSO 21 or a notification that there is a distribution system storage battery 40 to be disconnected has been received.
  • a disconnection request or a notification that there is a distribution system storage battery 40 to be disconnected is received, the process proceeds to step S126. If the disconnection request or the notification that there is a distribution system storage battery 40 to be disconnected is not received, the process proceeds to step S127.
  • step S126 the power conversion device 41a for the distribution system storage battery starts the disconnection process. After that, the process returns to step S121.
  • FIG. 24 is a flowchart showing a control process at the time of disconnection of the power conversion device 41 for the distribution system storage battery.
  • step S141 when the fourth control circuit 409 receives a disconnection request or the presence of the distribution system storage battery 40 to be disconnected, the fourth control circuit 409 controls the governor in the virtual synchronous generator control circuit 4093.
  • the control parameters in the circuit 40933 and the mass point system calculation circuit 40937 are changed.
  • the fourth control circuit 409 of the power conversion device 41 for the distribution system storage battery, which is not disconnected, also performs the same processing. Specifically, the fourth control circuit 409 sets the time constant value or the inertial constant value of the control parameters in the governor control circuit 40933 and the mass point system calculation circuit 40937 in order to suppress the system disturbance due to the disconnection. Make it larger than the value during normal operation.
  • the fourth control circuit 409 includes a control parameter of the power conversion device 41 for the distribution system storage battery to be disconnected and a control parameter of the power conversion device 41 for the distribution system storage battery to continue operation without disconnection. Set different values. More specifically, in the fourth control circuit 409, at least the time constant Tg in the governor control circuit 40933 is distributed so that the power conversion device 41 for the distribution system storage battery, which is disconnected, continues to operate without disconnecting. It is set to be larger than the power conversion device 41 for the grid storage battery.
  • the reason for setting this way is as follows.
  • the distribution system 24 is supported by a distributed power supply including the power conversion device 41 for the distribution system storage battery that is not disconnected. Therefore, the power that has been discharged or charged by the power conversion device 41 for the distribution system storage battery that has received the disconnection instruction is handled by the power conversion device 41 for the distribution system storage battery that is not disconnected or the distributed power supply.
  • the DSO 21 is disconnected together with the disconnection information of the power conversion device 41 for the distribution system storage battery. Notify the later power target value.
  • the target value (power target value) of the AC power output by the inverter by the target power generation circuit 40931 is set before the disconnection instruction is received. From the target value, narrow down to "zero" with a predetermined time or a predetermined inclination.
  • the target power generation circuit 40931 sets the power target value at a predetermined time from the target value before receiving the disconnection instruction, or at a predetermined value. The power target value notified when the disconnection information is received by the inclination is set.
  • the distribution system 24 generated by the arrangement can be minimized from shaking.
  • the eighth control circuit 4097 has at least the values of the control parameters (proportional gain and time constant) in the governor control circuit 40933 and the control parameters (inertial constants) in the quality point system arithmetic circuit 40937.
  • the value of braking coefficient is set larger than the value at the time of normal control.
  • the eighth control circuit 4097 determines the values of the time constant Tg in the governor control circuit 40933 and the inertial constant M in the quality point system arithmetic circuit 40937. Is set so that the power conversion device 41 for the distribution system storage battery to be disconnected is larger than the power conversion device 41 for the distribution system storage battery to be disconnected. As a result, the offset value added to the power target value output from the governor control circuit 40933 is suppressed to be smaller in the distribution system storage battery power conversion device 41 that is disconnected than in the distribution system storage battery power conversion device 41 that is not disconnected. Therefore, the disconnection operation can be performed smoothly.
  • the output fluctuation of the power conversion device 41 for the distribution system storage battery that is disconnected can be minimized. It can be suppressed to the limit. Further, since the inertial constant M in the mass point system arithmetic circuit 40937 is increased, the frequency of the AC voltage of the AC system generated by the power conversion device 41 for the distribution system storage battery to be disconnected does not change so much. Therefore, unnecessary disturbance is not given to the distribution system at the time of disconnection.
  • step S141 the process proceeds to step S142.
  • step S142 the eighth control circuit 4097 in the fourth control circuit 409 confirms whether the effective power output from the effective power calculation circuit 4092 is within a predetermined range. If the effective power is not within the predetermined range, the process waits until it falls within the predetermined range. When the effective power falls within the predetermined range, the process proceeds to step S143.
  • step S143 the eighth control circuit 4097 outputs an instruction to the communication interface circuit 412 to notify the DSO 21 that the sequence is to be performed.
  • step S144 the eighth control circuit 4097 disconnects the second DC / AC conversion circuit 408 from the distribution system 24. Specifically, the eighth control circuit 4097 outputs a command value to the second DC / AC conversion circuit 408 so that the output is "zero", and the second control circuit 404 is second. An instruction is output to stop the DC / DC conversion circuit 403.
  • the third control circuit 404 outputs a command value to the second DC / DC conversion circuit 403 (specifically, outputs a command value so that the charge / discharge power becomes “zero”), and then controls the fourth. Notify circuit 409.
  • the third control circuit 404 and the second DC / DC conversion circuit 403 shift to the low power consumption mode.
  • the fourth control circuit 409 receives the stop information of the second DC / DC conversion circuit 403 from the third control circuit 404, the fourth control circuit 409 has some functions other than the fourth control circuit 409 and the communication interface circuit 412. Shifts to the low power consumption mode and ends the disconnection process.
  • step S127 the power conversion device 41a for the distribution system storage battery determines whether or not new additional information has been received. When the newly added information is received, the process proceeds to step S128. If the newly added information is not received, the process returns to step S121.
  • step S1208 the power conversion device 41a for the distribution system storage battery changes the control parameters in the governor control circuit 40933 in the virtual synchronous generator control circuit 4093 and the mass point system calculation circuit 40937.
  • the reason for changing the control parameters in this way is as follows. Similar to the reason for disconnecting the power conversion device 41 for the distribution system storage battery described above, this is to suppress a large disturbance (change in frequency) with respect to the distribution system 24. In the case of a new input, as described above, an error occurs in the phase of the AC voltage of the AC system due to the measurement error (error of linearity, offset, etc.) of the voltmeter 410. As a result, when the power conversion device 41 for the distribution system storage battery is newly input, even if the power target value is "zero" based on the phase error, the phase error is large from the newly input power conversion device 41 for the distribution system storage battery. The power based on this is charged and discharged.
  • the power conversion device 41a for the distribution system storage battery usually sets the values of the control parameters in the governor control circuit 40933 in the virtual synchronous generator control circuit 4093 and the quality point system calculation circuit 40937. Set it larger than the value at the time of operation.
  • the inertial force of the synchronous generator simulated by the mass point system arithmetic circuit 40937 increases, so that the frequency and phase disturbance of the AC voltage of the AC system output from the second DC / AC conversion circuit 408 can be suppressed. can.
  • step S1208 when the change of the control parameters in the governor control circuit 40933 in the virtual synchronous generator control circuit 4093 and the mass point system calculation circuit 40937 is completed, the process proceeds to step S129.
  • step S129 the power conversion device 41 for the distribution system storage battery, which is interconnected to the grid, has a control parameter until the fluctuation of the frequency of the AC voltage of the AC system generated by the new input of the power conversion device 41 for the distribution system storage battery converges. Refrain from changing.
  • the power conversion device 41 for the distribution system storage battery, which is interconnected to the grid determines that this sway has converged by refraining from changing the control parameters for a predetermined time.
  • the determination of convergence of sway is not limited to this, and the power conversion device 41 for the distribution system storage battery, which is interconnected to the grid, has a frequency fluctuation width of the AC voltage of the AC system measured by the voltmeter 410 within a predetermined range. In some cases, it may be determined that the convergence has occurred.
  • the process proceeds to step S130.
  • step S130 the power conversion device 41 for the distribution system storage battery returns the control parameters in the governor control circuit 40933 in the virtual synchronous generator control circuit 4093 and the mass point system calculation circuit 40937 to the values at the time of normal operation. After that, the process returns to step S121.
  • FIG. 25 is a flowchart showing a control procedure when a power conversion device 41 for a distribution system storage battery is newly added.
  • step S161 the power conversion device 41 for the distribution system storage battery, which is on standby in the low power consumption mode, waits until a start request from the DSO 21 is received.
  • the process proceeds to step S162.
  • step S162 the eighth control circuit 4097 in the fourth control circuit 409 outputs an instruction to the third control circuit 404 to activate the second DC / DC conversion circuit 403.
  • the third control circuit 404 activates the second DC / DC conversion circuit 403.
  • the eighth control circuit 4097 sets a relay (not shown) connecting the distribution system storage battery 40 and the second DC / DC conversion circuit 403 to ON, and sets the DC bus 405 to a predetermined voltage. Charge until it becomes.
  • the third control circuit 404 collects various information of the distribution system storage battery 40 and notifies the fourth control circuit 409 of the result.
  • the eighth control circuit 4097 collects information such as SOC and deterioration progress by communicating with a battery management unit (not shown).
  • the fourth control circuit 409 When the fourth control circuit 409 receives various information including the information of the distribution system storage battery 40 from the third control circuit 404 (starting information of the second DC / DC conversion circuit 403, etc.), the fourth control circuit 409 The eighth control circuit 4097 sets the values of the governor control circuit 40933 in the virtual synchronous generator control circuit 4093 and the various control parameters in the quality point system calculation circuit 40937 to the values used at the time of new input.
  • the third switching circuit 4096 is controlled to select the output of the inverter voltage control circuit 4095.
  • the values of the control parameters in the governor control circuit 40933 in the virtual synchronous generator control circuit 4093 and the mass point system calculation circuit 40937 are larger than the values in the normal operation, as in the case of the above-mentioned disconnection.
  • various control parameters are set to values larger than the values at the time of disconnection. Specifically, at least the time constant (Tg) in the governor control circuit 40933 and the inertial constant (M) in the mass point system calculation circuit 40937 are set large. As a result, the response time of the governor control is slowed down, and the inertial force of the generator rotor according to the sway equation is apparently increased to suppress the change in the frequency of the AC voltage of the AC system of the distribution system 24.
  • the power not controlled by the newly introduced power conversion device 41 for the distribution system storage battery is the phase difference between the phase of the AC voltage of the AC system and the phase of the AC voltage output by the power conversion device 41 for the distribution system storage battery. This is the charge / discharge power generated due to the above.
  • the reason why this control method is established is shown below.
  • the power conversion device 41 for the distribution system storage battery is connected (interconnected) to the distribution system 24 by voltage control as described above. Therefore, if the excess or deficiency of the electric power in the distribution system 24 is equal to or less than the electric power capacity of the power conversion device 41 for the distribution system storage battery, the supply and demand balance can be ensured without any particular problem.
  • a power conversion device that controls the frequency of the AC voltage of the AC system as a current source connected to the distribution system 24 For example, you can receive support from a mega solar power converter 27).
  • the control is performed with priority given to reducing the frequency disturbance (frequency disturbance) of the AC voltage of the AC system rather than securing the SOC of the distribution system storage battery 40.
  • the inertial force of the synchronous generator simulated by the quality point system arithmetic circuit 40937 increases, so that the frequency of the AC voltage of the AC system output from the second DC / AC conversion circuit 408, And phase disturbance can be suppressed.
  • Tg time constant
  • the figure shows the governor control at the time when the normal control is started after the power conversion device 41 for the distribution system storage battery is newly input. Normal control can be restored without increasing the cumulative value of the frequency deviation stored in the integrator. As a result, it is possible to shorten the time from the new input to the stabilization of the frequency of the AC voltage of the AC system in the normal interconnection control.
  • step S162 When the process of step S162 is completed, the fourth control circuit 409 detects the frequency and phase of the AC voltage of the AC system.
  • step S163 the phase detection circuit 40910 detects the zero cross point from the measurement result of the AC voltage of the AC system output from the voltmeter 410. Specifically, the phase detection circuit 40910 obtains the time at the zero cross point by linear interpolation using the time information in which the output of the voltmeter 410 changes from negative to positive and the respective amplitudes.
  • the phase detection circuit 40910 calculates the time information of the zero cross point that changes from positive to negative as described above, calculates the offset error of the voltmeter 410 based on the calculation result of the time information of the zero cross point, and obtains the calculation result of the offset error. Based on this, the zero cross point time may be calculated again.
  • the phase detection circuit 40910 obtains the length of time when the AC voltage of the AC system is positive and the length of time when the AC voltage of the AC system is positive from the zero cross point time information which changes from negative to positive and the zero cross point time information which changes from positive to negative.
  • the phase detection circuit 40910 adds a negative offset value to the output of the voltmeter 410 if the length of the positive time is longer than the length of the negative time.
  • the phase detector circuit 40910 adds a positive offset value to the output of the voltmeter 410 if the length of the positive time is shorter than the length of the negative time.
  • the phase detection circuit 40910 repeats this process and corrects the offset value until the difference between the positive time length and the negative time length falls within a predetermined range.
  • the offset error of the voltmeter 410 can be reduced.
  • the method of calculating the offset error is not limited to this, and the same effect can be obtained even if the offset value is obtained so that the absolute values of the positive and negative peak voltages of the AC voltage of the AC system are almost the same, for example. ..
  • the frequency detection circuit 40911 detects the frequency by using the zero cross point information. Specifically, the frequency detection circuit 40911 calculates the frequency based on the time information of two consecutive zero cross points. In the first embodiment, the frequency of the AC voltage of the AC system is obtained by using only the time information of two consecutive zero cross points, but the present invention is not limited to this.
  • the frequency detection circuit 40911 may obtain the frequency of the AC voltage of the AC system based on the plurality of zero crossing point information, and may obtain the average value of the frequencies of the AC voltage of the plurality of AC systems.
  • the AC frequency detection circuit 4091 When the frequency detection is completed, the AC frequency detection circuit 4091 performs phase detection.
  • the phase detection circuit 40910 obtains the zero crossing point time at which the output of the latest voltmeter 410 when the frequency detection is completed changes from negative to positive, and uses it as phase information.
  • step S165 the frequency and phase information of the AC voltage of the AC system are input to the second sine wave generation circuit 40912.
  • the second sine wave generation circuit 40912 controls the voltage based on the detected frequency and phase information and the frequency information and phase information output from the quality point system arithmetic circuit 40937 in the virtual synchronous generator control circuit 4093. Generates sine wave information that serves as a reference. The second sine wave generation circuit 40912 outputs the generated sine wave information to the third sine wave generation circuit 40951 in the inverter voltage control circuit 4095.
  • the detection information of the AC frequency detection circuit 4091 (frequency information and phase information of the AC voltage of the AC system) is also input to the virtual synchronous generator control circuit 4093 and the eighth control circuit 4097.
  • the detection information input to the virtual synchronous generator control circuit 4093 is input to the target frequency generation circuit 40934.
  • the detection information of the AC frequency detection circuit 4091 is input to the mass point system calculation circuit 40937 via the eighth control circuit 4097. Specifically, the initial values of the integrator 409372 in the mass system arithmetic circuit 40937 and the register (not shown) in the phase calculation circuit 409376 are set.
  • step S165 When the setting of the frequency and phase information of the AC voltage of the AC system in step S165 is completed, the process proceeds to step S166.
  • step S166 the eighth control circuit 4097 sets the initial value of the frequency target value and the initial value of the power target value in the target power generation circuit 40931 and the target frequency generation circuit 40934 in the virtual synchronous generator control circuit 4093. ..
  • step S167 the target power generation circuit 40931 sets the time transition of the power target value.
  • the target frequency generation circuit 40934 sets the time transition of the frequency target value.
  • the target power generation circuit 40931 sets the power target value at the time of new input to "zero" as shown by the solid line in FIG. 13, and after the disturbance convergence of the distribution system 24 generated by the new input. It is controlled so that the power target value becomes Pre over a predetermined time. Therefore, the target power generation circuit 40931 calculates the slope of the straight line shown in FIG. 13 when the Pref is input. Then, when the convergence of the disturbance of the distribution system 24 is confirmed by the eighth control circuit 4097 after the target power generation circuit 40931 is newly input, the target power generation circuit 40931 generates a power target value based on the calculation result of the slope of the straight line. Output.
  • the power conversion device 41 for the newly input distribution system storage battery that has not been charged and discharged is controlled to output the power target value Pref immediately after the input, it is already connected to the system originally. This is because power is supplied from each distribution system storage battery power converter 41 in a state where supply and demand are balanced by the distribution system storage battery power converter 41 and the synchronous generator 30 that have been supplying power. be.
  • the power conversion device 41 for the distribution system storage battery (when the power target value is operating at the target value before the new input) and the synchronous generator 30 which have already been connected to the grid judge that the load has become lighter and output. Control to raise the frequency of the AC voltage of the AC system.
  • the power conversion device 41 for the distribution system storage battery newly input to the distribution system 24 increases the AC frequency when the output power (effective power) of the distribution system storage battery is smaller than that of the Pref. To control. Since the rate of frequency increase is determined by the impedance of the distribution system 24, the frequency increase rate of each distribution system storage battery power converter 41 and the synchronous generator 30 is different. As a result, unnecessary disturbance is applied to the distribution system 24. Therefore, the target power generation circuit 40931 in the power conversion device 41 for the distribution system storage battery to be newly input is controlled as described above.
  • the target power generation circuit 40931 is set after the disturbance of the distribution system 24 has converged, as shown by the one-point chain line in FIG.
  • a power target value is generated so as to change from the power target value Pref_b before the new input to the power target value Pref_a after the new input over a predetermined time.
  • the predetermined time in the target power generation circuit 40931 on the new input side and the predetermined time in the target power generation circuit 40931 during grid connection are the same. As a result, unnecessary disturbance (frequency disturbance) generated in the distribution system 24 when the power conversion device 41 for the distribution system storage battery is newly introduced is suppressed.
  • the target power generation circuit 40931 controls the power conversion device 41 for the distribution system storage battery to be newly input with the power target value set to zero immediately after the input, as shown by the solid line shown in FIG. After confirming the convergence of the system disturbance, the power target value is gradually increased from zero to Pre in a predetermined time.
  • the target power generation circuit 40931 sets the power target value (Pref_b) before the new input until the system disturbance immediately after the new input is resolved for the power conversion device 41 for the distribution system storage battery that has already been connected to the system. After confirming the convergence of the system disturbance, the power target value is gradually reduced from Pref_b to Pref_a at a predetermined time as shown by the alternate long and short dash line in FIG.
  • the target frequency generation circuit 40934 When the frequency (Fmesure) detected by the frequency detection circuit 40911 and the Fref are input, the target frequency generation circuit 40934 outputs the Fmesure as a frequency target value until the disturbance of the distribution system 24 converges. Then, when the convergence of the system disturbance is detected by the eighth control circuit 4097, the target frequency generation circuit 40934 outputs a frequency target value that changes from Fmesure to Fref over a predetermined time (see FIG. 14). .. In the virtual synchronous generator control, the frequency of the target AC voltage is controlled to be substantially the system frequency (for example, 60 Hz or 50 Hz) and does not change significantly.
  • the target frequency generation circuit 40934 outputs the frequency target value output from the eighth control circuit 4097 to the power conversion device 41 for the distribution system storage battery that was originally connected to the system. This is done because, as described for the target power generation circuit 40931, when the control of the frequency of the AC voltage of the AC system output by the power conversion device 41 for the distribution system storage battery is started immediately after the new power is input, the system is already in the system. Unnecessary disturbance will be given to the state where the power is supplied in a balanced manner with the load by the power generation equipment that has been interconnected and supplied the power. Therefore, immediately after the power conversion device for the distribution system storage battery is newly input, it can be controlled without giving unnecessary disturbance to the AC system by being controlled by the frequency (Fmesure) of the detected AC voltage of the AC system.
  • step S168 an initialization process for controlling the second DC / AC conversion circuit 408 is performed.
  • the operation of the second DC / AC conversion circuit 408 will be described with reference to FIG. 26.
  • FIG. 26 is a flowchart showing a control procedure of the fourth control circuit 409 when a new power conversion device 41 for a distribution system storage battery is turned on.
  • step S181 when the control of the second DC / AC conversion circuit 408 is started, the effective power calculation circuit 4092 in the fourth control circuit 409 calculates the effective power. That is, the effective power calculation circuit 4092 obtains the effective power by integrating the electric energy for one cycle of the AC voltage of the AC system based on the zero cross point information and the frequency detection information detected by the AC frequency detection circuit 4091. .. Specifically, the effective power calculation circuit 4092 calculates the amount of power for one cycle of the AC voltage of the AC system based on the zero cross point detection information in which the AC voltage of the AC system switches from negative to positive.
  • the effective power calculation circuit 4092 calculates the unit effective power amount by multiplying the output of the voltmeter 410 and the output of the ammeter 411 and dividing the multiplication result by the sampling period. Further, the effective power calculation circuit 4092 integrates the unit effective power amount for one cycle of the AC voltage of the AC system. The effective power calculation circuit 4092 calculates the effective power by multiplying the integration result by the frequency information output from the AC frequency detection circuit 4091.
  • step S182 the eighth control circuit 4097 confirms whether or not the current time is within the control cycle.
  • one cycle of the AC voltage of the AC system is set as the control cycle.
  • the control cycle may be an integral multiple of the cycle of the AC voltage of the AC system, or a predetermined cycle such as a 1-second cycle. If the current time is within the control cycle, the process proceeds to step S183.
  • step S183 the eighth control circuit 4097 outputs an instruction to the target power generation circuit 40931 in the virtual synchronous generator control circuit 4093 to generate an initial value of the power target value.
  • the target power generation circuit 40931 generates an initial value of the power target value as shown in FIG. 13 in the manner described as receiving the instruction.
  • step S184 the eighth control circuit 4097 outputs an instruction to the target frequency generation circuit 40934 in the virtual synchronous generator control circuit 4093 to generate an initial value of the frequency target value.
  • the target frequency generation circuit 40934 Upon receiving the instruction, the target frequency generation circuit 40934 generates an initial value of the frequency target value as shown in FIG. 14 as described above.
  • step S185 the eighth control circuit 4097 generates frequency information and phase information when generating an AC voltage target value when controlling the second DC / AC conversion circuit 408 with respect to the virtual synchronous generator control circuit 4093. Output instructions to generate.
  • the virtual synchronous generator control circuit 4093 detects the frequency and phase of the AC voltage of the AC system of the distribution system 24 with respect to the phase detection circuit 40910 and the frequency detection circuit 40911 in the AC frequency detection circuit 4091. Output instructions to do so.
  • the zero cross point information detected by the AC frequency detection circuit 4091 includes an error due to the influence of the sensor error of the voltmeter 410. Therefore, for example, the power conversion device 41 for the distribution system storage battery is newly introduced for the purpose of using it in the discharge direction (power running direction), and the phase of the AC voltage of the AC system output from the second DC / AC conversion circuit 408 is the distribution system.
  • the phase is slow with respect to the AC voltage phase of 24, as described with reference to FIG. 19, the newly introduced power conversion device 41 for the distribution system storage battery operates in the charging direction (regeneration direction) immediately after the charging.
  • the other distribution system storage battery power conversion device 41 and the synchronous generator 30 that have been system-connected need to supplement the power charged by the newly introduced distribution system storage battery power conversion device 41 by discharging. Due to the addition of the discharge power, the output of the power conversion device 41 for the distribution system storage battery exceeds the power capacity of the power conversion device 41 for the distribution system storage battery. As a result, the power conversion device 41 for the distribution system storage battery may stop due to overpower.
  • the fourth control circuit 409 outputs from the power conversion device 41 for the distribution system storage battery at the time of new input.
  • Phase information detected by the AC frequency detection circuit 4091 so that the phase of the AC voltage of the AC system is the phase advance phase with respect to the AC voltage phase of the distribution system 24 (in the first embodiment, the AC voltage of the AC system is It is controlled so that a predetermined amount of offset is added to (zero cross point time information) when switching from negative to positive. Specifically, a predetermined time is subtracted from the zero crossing point time detected by the AC frequency detection circuit 4091 and output.
  • the method of controlling so as to have a phase-advancing phase is not limited to this method.
  • the second sine wave generation circuit 40912 when controlling the second DC / AC conversion circuit 408 during grid connection, the second sine wave generation circuit 40912 The same applies even if the offset amount given at the time of new input is calculated from the zero cross point time information of the sine wave waveform which is the target value of the voltage control output from and the zero cross point time information detected by the phase detection circuit 40910. The effect is obtained.
  • the second DC / AC conversion is performed so that the phase of the AC voltage of the output AC system is advanced by the fourth control circuit 409.
  • the circuit 408 is controlled, as shown in FIG. 21, the newly input power distribution system storage battery power conversion device 41 outputs electric power in the discharge direction (power running direction) immediately after the circuit 408 is input. Since the other distribution system storage battery power conversion device 41 and the synchronous generator 30 that have been grid-connected operate in the direction of suppressing the discharge power, control can be performed without exceeding the power capacity of the distribution system storage battery power conversion device 41. can. As a result, the power conversion device 41 for the distribution system storage battery in the grid connection can continue to operate.
  • step S169 the eighth control circuit 4097 starts virtual synchronous generator control.
  • the inverter voltage control circuit 4095 performs the power conversion device 41 for the distribution system storage battery based on the frequency and phase (zero cross point detection time information) information detected in step S185 of FIG. 26.
  • the target value of the AC voltage of the AC system output from is generated by using the third sine wave generation circuit 40951.
  • the inverter voltage control circuit 4095 generates and outputs a control signal of the second DC / AC conversion circuit 408 based on the target value of the AC voltage of the generated AC system.
  • the virtual synchronous generator control circuit 4093 starts the virtual synchronous generator control.
  • the subtractor 40923 subtracts the output of the target frequency generation circuit 40934 from the frequency of the measured AC voltage of the AC system output from the frequency detection circuit 40911, and the subtraction result is obtained. Is sent to the governor control circuit 40933.
  • the multiplier 409331 multiplies the output of the subtractor 40923 with the control parameter (-1 / Kgd) output from the eighth control circuit 4097, and sends the multiplication result to the first-order lag model 409332. ..
  • the first-order lag system model 409332 uses the time constant Tg output from the eighth control circuit 4097 to perform an operation simulating the first-order lag system (1 / (1 + s ⁇ Tg)), and obtains the calculation result in the limiter circuit 409333. Send to.
  • the limiter circuit 409333 limits the input data. Specifically, the limiter circuit 409333 limits the output so as not to exceed the power capacity of the second DC / AC conversion circuit 408.
  • the output of the governor control circuit 40933 is added to the power target value output from the target power generation circuit 40931 by the adder 40935.
  • the subtractor 40936 subtracts the output of the adder 40935 from the measured effective power output from the effective power calculation circuit 4092.
  • the output of the subtractor 40936 is input to the mass system arithmetic circuit 40937.
  • the subtractor 409371 subtracts the output of the multiplier 409373 from the output of the subtractor 40936 and sends the subtraction result to the integrator 409372.
  • the integrator 409372 divides the subtraction result by the inertial constant M output from the eighth control circuit 4097, and integrates the division result.
  • the output of the integrator 409372 ( ⁇ : the difference value from the angular velocity of the AC system frequency (2 ⁇ ⁇ ⁇ 60 Hz)) is input to the multiplier 409373 and the divider 409374.
  • the multiplier 409373 multiplies the output ⁇ of the integrator 409372 by the braking coefficient Dg output from the eighth control circuit 4097, and outputs the multiplication result to the subtractor 409371.
  • the divider 409374 divides the output ⁇ of the integrator 409372 by 2 ⁇ ⁇ and converts ⁇ into a ⁇ f (difference value from the AC system frequency (60 Hz)) value.
  • the output of the divider 409374 is added by the adder 409375 to 60 Hz, which is the reference frequency of the AC voltage of the AC system, so that the frequency at which the inverter voltage control circuit 4095 performs voltage control is generated.
  • the frequency information output from the adder 409375 is input to the phase calculation circuit 409376.
  • the operation of the phase calculation circuit 409376 will be described below.
  • the operation of the phase calculation circuit 409376 differs between the time of new input and the time of grid connection.
  • the phase calculation circuit 409376 integrates the frequency information output from the adder 409375, and calculates the phase when the inverter voltage control circuit 4095 performs voltage control from the integration result.
  • the calculated phase information and frequency information are input to the third sine wave generation circuit 40951 in the inverter voltage control circuit 4095 via the second sine wave generation circuit 40912 in the AC frequency detection circuit 4091.
  • the third sine wave generation circuit 40951 uses the received phase information and frequency information to generate a target value of the AC voltage of the AC system output from the power conversion device 41 for the distribution system storage battery.
  • the eighth control circuit 4097 confirms whether or not the predetermined time has elapsed.
  • the predetermined time is the time required for the disturbance convergence of the distribution system after the power conversion device 41 for the distribution system storage battery is newly introduced. Specifically, the predetermined time is equal to or longer than the time required for the output of the target power generation circuit 40931 to become Def and the output of the target frequency generation circuit 40934 to become Def in FIG. 13 or 14. If the predetermined time has not elapsed, the process proceeds to step S171. If the predetermined time has elapsed, the process proceeds to step S172.
  • step S171 the eighth control circuit 4097 collects various measurement data. After that, the process proceeds to step S169.
  • step S172 the eighth control circuit 4097 changes various parameters for virtual synchronous generator control set for new input in S162 to control parameters for normal grid interconnection. After that, the process shifts to normal control (see FIG. 23).
  • the power distribution system when the power conversion device 41 for the power distribution system storage battery is newly applied to the power distribution system 24 in the discharge direction (power running direction) by the voltage source (voltage control), the power distribution system
  • the phase of the AC voltage of the AC system output from the power conversion device 41 for the storage battery is compared with the phase information detected by the phase detection circuit 40910 to be the phase-advancing phase.
  • the power is input at least in the phase-advancing phase.
  • the conversion device 41 can input the electric power from the distribution system 24 without unnecessary charging. As a result, there is an effect that the operation can be surely continued without unnecessarily increasing the discharge power of the power conversion device 41 for the distribution system storage battery in the grid connection.
  • control parameters (time constant Tg) of the governor control circuit 40933 in the virtual synchronous generator control circuit 4093, and the control parameters (time constant Tg) of the governor control circuit 40933 in the virtual synchronous generator control circuit 4093 when the power conversion device 41 for the distribution system storage battery is newly input or disconnected are made larger than the value at the time of normal control. This is carried out not only in the power conversion device 41 for the distribution system storage battery that is newly input or disconnected, but also in the power conversion device 41 for the distribution system storage battery that continues to be connected.
  • At least the inertial constant M in the quality point system calculation circuit 40937 is set to be larger in the power conversion device 41 for the distribution system storage battery during continuous operation. This is because the phase of the AC voltage of the AC system of the power conversion device 41 for the distribution system storage battery to be newly input is advanced in order to suppress the influence of the sensing error of the voltmeter 410.
  • the phase of the AC voltage of the AC system of the newly input distribution system storage battery power conversion device 41 is adjusted. It is necessary to control the phase for grid connection by virtual synchronous generator control.
  • the response performance for frequency and phase control by the quality point system calculation circuit 40937 should be set higher than that for the power conversion device 41 for the distribution system storage battery in the grid interconnection. Therefore, the time during which the frequency disturbance occurs can be shortened.
  • the target power generation circuit 40931 and the target frequency generation circuit 40934 in the virtual synchronous generator control circuit 4093 are controlled as shown in FIGS. 13 and 14.
  • various controls of the governor control circuit 40933 and the mass point system calculation circuit 40937 can be smoothly executed when the power conversion device 41 for the distribution system storage battery is newly introduced.
  • Embodiment 2 In the first embodiment, the case where the power conversion device 41 for the distribution system storage battery is newly input in the discharge direction (power running direction) has been described, but in the second embodiment, the power conversion device 41 for the distribution system storage battery is charged in the charging direction (regeneration direction). ) Will be described for the case of new input. Therefore, the configuration of the power conversion device 41 for the distribution system storage battery in the second embodiment is the same as the configuration of the first embodiment (see FIGS. 4 and 7, 8, 10 to 12, 15, 16). Only the control of the mass point system arithmetic circuit 40937 in the power conversion device 41 for the distribution system storage battery newly added to the system is different. Hereinafter, the operation of different parts will be mainly described.
  • FIG. 27 is a flowchart showing a control procedure at the time of newly adding the power conversion device 41 for the distribution system storage battery (newly input for the purpose of charging direction (regeneration direction)) in the second embodiment.
  • the power conversion device 41 for the distribution system storage battery which is on standby in the low power consumption mode, waits until a start request from the DSO 21 is received (S161).
  • the eighth control circuit 4097 in the fourth control circuit 409 activates the second DC / DC conversion circuit 403 with respect to the third control circuit 404.
  • Output instructions Since the control at the time of starting the third control circuit 404 is the same as that in the first embodiment, the detailed description of the operation will not be repeated.
  • the third control circuit 404 When the third control circuit 404 finishes the start-up process including the distribution system storage battery 40, the third control circuit 404 notifies the fourth control circuit 409 together with the information collected to that effect.
  • the eighth control circuit 4097 in the fourth control circuit 409 is the governor control circuit 40933 in the virtual synchronous generator control circuit 4093, and the mass point system calculation circuit.
  • the various control parameters in 40937 are set to the parameters used at the time of new input.
  • the third switching circuit 4096 controls to select the output of the inverter voltage control circuit 4095.
  • the control parameters of each control circuit in the virtual synchronous generator control circuit 4093 are changed for new input.
  • the eighth control circuit 4097 sets the values of the control parameters in the governor control circuit 40933 in the virtual synchronous generator control circuit 4093 and the mass point system calculation circuit 40937 larger than the values in the normal operation. do. At that time, as in the first embodiment, the eighth control circuit 4097 makes the values of these control parameters even larger than the values of the control parameters set at the time of disconnection. Specifically, the eighth control circuit 4097 increases at least the time constant (Tg) in the governor control circuit 40933 and the inertial constant (M) in the mass system arithmetic circuit 40937.
  • Tg time constant
  • M inertial constant
  • the response time of the governor control becomes slow, and the inertial force of the generator rotor shown in FIG. 9 according to the sway equation becomes apparently large.
  • the power conversion device 41 for the distribution system storage battery is newly input, even if the power not controlled by the newly input power conversion device 41 for the distribution system storage battery is output, the AC voltage of the AC system is changed. The operation can be continued without the frequency being greatly disturbed.
  • the uncontrolled power is charge / discharge power generated due to the phase difference between the phase of the AC voltage of the AC system and the phase of the AC voltage output by the power conversion device 41 for the distribution system storage battery. Since the principle and effect of this method are the same as those in the first embodiment, the description will not be repeated.
  • step S163 similarly to the first embodiment, the fourth control circuit 409 detects the phase (zero cross point time) of the AC voltage of the AC system and outputs the zero cross point time information to the frequency detection circuit 40911.
  • step S164 the frequency detection circuit 40911 detects the frequency of the AC voltage of the AC system based on the zero cross point time information.
  • the phase detection circuit 40910 in the AC frequency detection circuit 4091 uses the time information in which the output of the voltmeter 410 changes from negative to positive and the respective amplitudes to zero cross point time. Is obtained by linear interpolation. Then, the frequency of the AC voltage of the AC system is calculated based on the time information of the zero crossing points of two consecutive points of the frequency detection circuit 40911.
  • the frequency detection circuit 40911 is configured to obtain the frequency of the AC voltage of the AC system by using only the time information of two consecutive zero cross points, but the present invention is not limited to this.
  • the frequency detection circuit 40911 may obtain the frequency of the AC voltage of the AC system based on the plurality of zero crossing point information and take an average value.
  • the phase detection circuit 40910 calculates the time information of the zero cross point that changes from positive to negative as described above, and calculates the offset error of the voltmeter 410 based on the calculation result (details are as follows). , The zero crossing point time may be calculated again based on the offset error.
  • the AC frequency detection circuit 4091 detects the phase of the AC voltage of the AC system. Similar to the first embodiment, the AC frequency detection circuit 4091 uses the zero cross point time at which the output of the latest voltmeter 410 when the frequency detection is completed changes from negative to positive as the phase information.
  • the process proceeds to step S165.
  • step S165 the frequency information and the phase information detected by the AC frequency detection circuit 4091 are input to the second sine wave generation circuit 40912.
  • the second sine wave generation circuit 40912 controls the voltage based on the detected frequency information and phase information and the frequency information and phase information output from the quality point system arithmetic circuit 40937 in the virtual synchronous generator control circuit 4093.
  • the sine wave information that serves as a reference is generated and output to the third sine wave generation circuit 40951 in the inverter voltage control circuit 4095.
  • the detection information of the AC frequency detection circuit 4091 is also input to the virtual synchronous generator control circuit 4093 and the eighth control circuit 4097.
  • the frequency and phase of the AC voltage of the AC system input to the virtual synchronous generator control circuit 4093 are input to the target frequency generation circuit 40934.
  • the detection information of the AC frequency detection circuit 4091 is input to the mass point system calculation circuit 40937 via the eighth control circuit 4097. Specifically, the detection information is set to the initial value of the integrator 409372 in the mass system arithmetic circuit 40937 and the register (not shown) in the phase calculation circuit 409376.
  • step S165 When the setting of the frequency information and the phase information of the AC voltage of the AC system is completed in step S165, the process proceeds to step S166.
  • step S166 the eighth control circuit 4097 has the initial value and the power of the frequency target value in the target power generation circuit 40931 in the virtual synchronous generator control circuit 4093 and the target frequency generation circuit 40934, as in the first embodiment. Set the initial value of the target value.
  • step S167 the target power generation circuit 40931 sets the time transition of the power target value. Since the specific operation (target value generation operation) and effect of the target power generation circuit 40931 and the target frequency generation circuit 40934 are the same as those in the first embodiment, the description will not be repeated.
  • FIG. 28 is a flowchart showing a control procedure when a new power conversion device 41 for a power distribution system storage battery of the fourth control circuit 409 in the second embodiment is input.
  • the operation of the second DC / AC conversion circuit 408 will be described with reference to FIG. 28.
  • step S181 when the control of the second DC / AC conversion circuit 408 is started, the effective power calculation circuit 4092 in the fourth control circuit 409 calculates the effective power.
  • the method of calculating the AC effective electric power is the same as that of the first embodiment.
  • step S182 the eighth control circuit 4097 confirms whether or not the current time is within the control cycle.
  • one cycle of the AC voltage of the AC system is set as the control cycle.
  • the control cycle may be an integral multiple of the cycle of the AC voltage of the AC system, or a predetermined cycle such as a 1-second cycle.
  • step S183 If it is determined that the current time is within the control cycle, the process proceeds to step S183.
  • step S183 The eighth control circuit 4097 outputs an instruction to the target power generation circuit 40931 in the virtual synchronous generator control circuit 4093 to generate an initial value of the power target value.
  • step S184 the eighth control circuit 4097 outputs an instruction to the target frequency generation circuit 40934 in the virtual synchronous generator control circuit 4093 to generate an initial value of the frequency target value.
  • the target frequency generation circuit 40934 Upon receiving the instruction, the target frequency generation circuit 40934 generates an initial value of the frequency target value as described above.
  • the target power generation circuit 40931 and the target frequency generation circuit 40934 are shown in FIGS. 13 and 40 as in the first embodiment. As shown in No. 14, a voltage target value and a frequency target value are generated.
  • the eighth control circuit 4097 is the power conversion device 41 for the distribution system storage battery when the second DC / AC conversion circuit 408 is newly input to the distribution system 24 with respect to the AC frequency detection circuit 4091. Outputs an instruction to generate the target value of the AC voltage of the AC system output from.
  • the AC frequency detection circuit 4091 causes the phase detection circuit 40910 and the frequency detection circuit 40911 to generate the frequency of the AC voltage of the AC system input from the distribution system 24 and the zero cross point time information. Output instructions. Details of the method for detecting the frequency and zero crossing point time information of the AC voltage of the AC system input from the distribution system 24 in the second embodiment will be described later.
  • the second embodiment is different from the first embodiment in that the power conversion device 41 for the distribution system storage battery is operated in the charging direction (regeneration direction) in order to charge the surplus power of the mega solar 26.
  • the device 41 is newly introduced.
  • the phase of the AC voltage of the AC system of the distribution system 24 and the power conversion device 41 for the distribution system storage battery are output.
  • the output power is determined by the phase difference between the AC voltage of the AC system and the phase of the AC voltage.
  • the phase of the AC voltage target value since the phase of the AC voltage target value is set to the phase-advancing phase with respect to the AC voltage of the AC system, the power determined by the phase difference in the discharge direction (force running direction) as shown in FIGS. 20 and 21. Is output.
  • the phase of the AC voltage target value is a slow phase with respect to the AC voltage of the AC system
  • power determined by the phase difference is output in the charging direction (regeneration direction) as shown in FIGS. 18 and 19.
  • This power is actually, in addition to the magnitude of the phase difference, the magnitude of the difference between the amplitude of the AC voltage of the AC system of the distribution system 24 and the amplitude of the AC voltage of the AC system output by the power conversion device 41 for the distribution system storage battery.
  • the fourth control circuit 409 sets the frequency of the AC voltage target value to the AC frequency when the second DC / AC conversion circuit 408 (inverter) is input to the AC system.
  • the frequency of the AC voltage detected by the detection circuit 4091 is used, and when the target value of the AC power is in the regeneration direction, the phase of the AC voltage target value is controlled so as to be at least slower than the AC voltage of the AC system. do.
  • the fourth control circuit 409 adds a predetermined amount offset to the phase information detected by the AC frequency detection circuit 4091, or controls the zero cross point detection time so that the offset is added.
  • the phase information is the zero crossing point time information when the AC voltage of the AC system is switched from negative to positive in the second embodiment, as in the first embodiment.
  • the fourth control circuit 409 adds a predetermined time to the zero crossing point time detected by the AC frequency detection circuit 4091 and outputs the output.
  • the method of controlling the phase of the AC voltage target value so that the phase is delayed with respect to the AC voltage of the AC system is not limited to this method.
  • Zero cross point time information is generated. Specifically, as described in the operation description of the AC frequency detection circuit 4091, the AC frequency detection circuit 4091 calculates three consecutive zero cross point times based on the measurement data of the voltmeter 410.
  • the three consecutive zero-cross point times are the zero-cross point time t1 in which the AC voltage of the AC system switches from negative to positive, the zero-cross point time t2 in which the AC voltage switches from positive to negative, and the zero-cross point time t3 in which the AC voltage switches from negative to positive.
  • FIGS. 29 (a) to 29 (c) are diagrams for explaining a method of detecting the zero cross point time (phase) of the slow phase.
  • FIGS. 29 (a) to 29 (c) show voltage information output from the voltmeter 410.
  • the vertical axis represents voltage and the horizontal axis represents time.
  • the phase detection circuit 40910 in the AC frequency detection circuit 4091 calculates the zero cross point times t1, t2, and t3 as described in the first embodiment. For example, the phase detection circuit 40910 linearly interpolates the zero cross point times t1, t2, and t3 using the time information between two consecutive samples in which the output from the voltmeter 410 switches from negative to positive and the two positive and negative sample values. And calculate.
  • the phase detection circuit 40910 calculates Tu_d and Td_u based on the calculated zero cross point time information. Then, in the second embodiment, the phase detection circuit 40910 sets Tstatic_max and Tstatic_min as the phase-advancing phase when the phase of the AC voltage of the AC system output from the power conversion device 41 for the distribution system storage battery is set as the phase-advancing phase. Assuming that the predetermined value is used for detection, the offset value (phase advance) is determined so that the following equation is established (see FIG. 29 (b)).
  • the time t3 in FIG. 29B is set as the zero cross point detection time of the phase advance phase.
  • the time t3 in FIG. 29 (c) is set as the zero cross point detection time of the late phase.
  • the same effect can be obtained by controlling the phase of the AC voltage of the AC system output from the power conversion device 41 for the distribution system storage battery.
  • the zero cross point time information and the phase of the sine wave waveform which is the target value of the voltage control output from the second sine wave generation circuit 40912 when controlling the second DC / AC conversion circuit 408 during grid connection. The same effect can be obtained even if the offset amount given at the time of new input is calculated from the zero cross point time information detected by the detection circuit 40910.
  • the zero cross point time information t1 and t3 detected by the phase detection circuit 40910 are input to the frequency detection circuit 40911.
  • the frequency detection circuit 40911 calculates the frequency fx of the AC voltage of the AC system of the distribution system 24 by the following formula.
  • the third sine wave generation circuit 40951 generates a target value of the AC system voltage output from the power conversion device 41 for the distribution system storage battery based on the notified sine wave information.
  • the timing at which the power conversion device 41 for the distribution system storage battery is input to the distribution system 24 is the timing of the zero crossing point of the target value of the AC system voltage generated by the third sine wave generation circuit 40951.
  • step S210 When the calculation of the frequency and phase information (zero cross point time information) of the AC voltage of the AC system is completed in step S210, the process proceeds to step S169 of FIG. 27.
  • step S169 the eighth control circuit 4097 outputs an instruction to the virtual synchronous generator control circuit 4093 to start the virtual synchronous generator control.
  • the third sine wave generation circuit 40951 of the inverter voltage control circuit 4095 is a power distribution system based on the frequency and phase (zero cross point detection time information) information detected in step S210.
  • a target value of the AC voltage of the AC system output from the power conversion device 41 for the storage battery is generated.
  • the inverter voltage control circuit 4095 generates and outputs a control signal of the second DC / AC conversion circuit 408 based on the target value of the AC voltage of the generated AC system.
  • the virtual synchronous generator control circuit 4093 starts the virtual synchronous generator control.
  • the governor control circuit 40933 subtracts and subtracts the output of the target frequency generation circuit 40934 from the frequency of the measured AC voltage of the AC system output from the frequency detection circuit 40911. The result is output to the governor control circuit 40933.
  • the multiplier 409331 of the governor control circuit 40933 multiplies the output of the subtractor 40923 with the control parameter (-1 / Kgd) output from the eighth control circuit 4097, and outputs the multiplication result to the first-order lag model 409332. ..
  • the first-order lag system model 409332 performs an operation simulating the first-order lag system (1 / (1 + s ⁇ Tg)) using the time constant Tg output from the eighth control circuit 4097, and transfers the calculation result to the limiter circuit 409333. Output.
  • the limiter circuit 409333 limits the input data. Specifically, the limiter circuit 409333 limits the output so as not to exceed the power capacity of the second DC / AC conversion circuit 408.
  • the adder 40935 adds the output of the governor control circuit 40933 and the power target value output from the target power generation circuit 40931.
  • the subtractor 40936 subtracts the output of the adder 40935 from the measured effective power output from the effective power calculation circuit 4092.
  • the output of the subtractor 40936 is input to the mass system arithmetic circuit 40937.
  • the subtractor 409371 subtracts the output of the multiplier 409373 from the output of the subtractor 40936 and outputs the subtraction result to the integrator 409372.
  • the integrator 409372 divides the subtraction result by the inertial constant M output from the eighth control circuit 4097, and integrates the division result.
  • the output of the integrator 409372 ( ⁇ : the difference value from the angular velocity of the AC system frequency (2 ⁇ ⁇ ⁇ 60 Hz)) is input to the multiplier 409373 and the divider 409374.
  • the multiplier 409373 multiplies the output ⁇ of the integrator 409372 and the braking coefficient Dg output from the eighth control circuit 4097, and outputs the multiplication result to the subtractor 409371.
  • the divider 409374 divides the output ⁇ of the integrator 409372 by 2 ⁇ ⁇ and converts ⁇ into a ⁇ f (difference value from the AC system frequency (60 Hz)) value.
  • the output of the divider 409374 is added by the adder 409375 to 60 Hz, which is the reference frequency of the AC voltage of the AC system. by this.
  • a frequency is generated when voltage control is performed in the inverter voltage control circuit 4095.
  • the frequency information output from the adder 409375 is input to the phase calculation circuit 409376.
  • the operation of the phase calculation circuit 409376 will be described below.
  • the operation of the phase calculation circuit 409376 differs between when it is newly input and when it is connected to the grid.
  • the phase calculation circuit 409376 integrates the frequency information output from the adder 409375, and calculates the phase when the inverter voltage control circuit 4095 performs voltage control from the integration result.
  • the calculated phase information and frequency information are input to the third sine wave generation circuit 40951 in the inverter voltage control circuit 4095 via the second sine wave generation circuit 40912 in the AC frequency detection circuit 4091.
  • the third sine wave generation circuit 40951 generates a target value of the AC voltage of the AC system output from the power conversion device 41 for the distribution system storage battery based on the phase information and the frequency information.
  • the eighth control circuit 4097 confirms whether or not the effective power calculated by the effective power calculation circuit 4092 is within a predetermined power range. That is, the eighth control circuit 4097 confirms whether or not the disturbance of the charge / discharge power of the power conversion device 41 for the distribution system storage battery newly input to the distribution system 24 is within a predetermined range. If the effective power is not within the predetermined range, the process proceeds to step S171. If the effective power is within the predetermined range, the process proceeds to step S204.
  • step S171 the eighth control circuit 4097 collects various measurement data. After that, the process returns to step S169.
  • step S169 the eighth control circuit 4097 again controls the virtual synchronous generator control circuit 4093.
  • the target power generation circuit 40931 and the target frequency generation circuit 40934 in the virtual synchronous generator control circuit 4093 maintain the initial values until the disturbance converges. (See FIGS. 13 and 14).
  • step S204 the eighth control circuit 4097 confirms whether or not the output of the target power generation circuit 40931 in the virtual synchronous generator control circuit 4093 is Pre and the output of the target frequency generation circuit 40934 is Fref.
  • the process proceeds to step S172. If the output of the target power generation circuit 40931 is not Def, or the output of the target frequency generation circuit 40934 is not Def, the process proceeds to step S205.
  • step S205 the eighth control circuit 4097 collects various measurement data. After that, the process returns to step S204.
  • step S172 the eighth control circuit 4097 changes various parameters for virtual synchronous generator control set for new input in step S162 to control parameters for normal grid interconnection. After that, the process shifts to normal control (see FIG. 23).
  • the second embodiment is configured as described above, when the power conversion device 41 for the distribution system storage battery is newly applied to the distribution system 24 in the charging direction (regeneration direction) by the voltage source (voltage control), the power is distributed.
  • the phase of the AC voltage of the AC system output from the power conversion device 41 for the system storage battery is compared with the phase information detected by the phase detection circuit 40910 to be a slow phase phase.
  • the measurement error is superimposed on the phase of the AC voltage waveform of the AC system of the distribution system 24 due to the sensing error of the voltmeter 410 or the like, it is input at least in the slow phase phase, so that it is newly input immediately after the input. It is possible to prevent the power conversion device 41 for the distribution system storage battery from unnecessarily discharging the power to the distribution system 24.
  • FIG. 30 shows the charge / discharge power (effective value) of the two power distribution system storage battery power conversion devices 41 when the AC voltage phase of the newly input power distribution system storage battery power conversion device 41 in the second embodiment is slow. It is a figure which shows.
  • the power conversion device 41a for the distribution system storage battery which has been interconnected to the grid, increases the charging power. As a result, it is possible to prevent the output power of the power conversion device 41a for the distribution system storage battery from exceeding the maximum charging power and the power conversion device 41a for the distribution system storage battery from stopping due to the capacity being exceeded. As a result, there is an effect that the operation can be surely continued without unnecessarily increasing the discharge power of the power conversion device 41a for the distribution system storage battery in the grid connection.
  • the control parameter (time constant) of the governor control circuit 40933 in the virtual synchronous generator control circuit 4093. Tg) and the value of the control parameter (inertial constant M) in the quality point system calculation circuit 40937 are increased as compared with the value at the time of normal control.
  • this also implements the power conversion device 41 for the distribution system storage battery that continues to be connected.
  • At least the inertial constant M in the quality point system arithmetic circuit 40937 is compared with the power conversion device 41 for the distribution system storage battery to be newly input, and the power conversion device for the distribution system storage battery during continuous operation. 41 is set to be larger.
  • the reason for this is as follows.
  • the phase of the AC voltage of the AC system of the power conversion device 41 for the newly input distribution system storage battery is delayed in order to suppress the influence of the sensing error of the voltmeter 410.
  • the phase of the AC voltage of the AC system of the newly input distribution system storage battery power conversion device 41 is adjusted.
  • the response performance of the frequency and phase control by the quality point system calculation circuit 40937 is set higher than that of the power conversion device 41 for the distribution system storage battery in the grid interconnection. This makes it possible to shorten the time during which the frequency disturbance occurs.
  • the target power generation circuit 40931 and the target frequency generation circuit 40934 in the virtual synchronous generator control circuit 4093 are controlled as shown in FIGS. 13 and 14.
  • various controls of the governor control circuit 40933 and the mass point system calculation circuit 40937 can be smoothly executed when the power conversion device 41 for the distribution system storage battery is newly introduced. resulting in. It is possible to prevent an unnecessary frequency disturbance from occurring in the distribution system 24.
  • an offset is added to the zero cross point time detected by the phase detection circuit 40910 even when the voltmeter 410 is not guaranteed the offset error and the linearity at the time of sensing (from DSO21).
  • an offset is added to the voltmeter 410 so that the phase is slow, and the zero cross point time is calculated.
  • the 41 has the effect of being able to reliably continue the operation without unnecessarily increasing the charge / discharge power.
  • the present invention is not limited to this.
  • the same effect can be obtained by similarly controlling the power conversion device 41 for a power distribution system storage battery installed in a factory composed of a power transmission system or a self-employed line, or inside a building.
  • the power conversion device 41 for the distribution system storage battery has been described, but the present invention is not limited to this.
  • a static inverter as a voltage source
  • solar ionization for example, solar ionization
  • a wind power generator or a system that supplies generated power from a fuel cell to the system
  • the same effect can be obtained by controlling.
  • an in-vehicle storage battery such as an electric vehicle (EV: Electric Vehicle), a plug-in type hybrid vehicle (PHEV: Plug-in Hybrid Electric Vehicle), or a fuel cell vehicle (FCV: Fuel Cell Vehicle).
  • EV Electric Vehicle
  • PHEV Plug-in Hybrid Electric Vehicle
  • FCV Fuel Cell Vehicle
  • the case of single-phase alternating current has been described as an example for the sake of simplicity, but the present invention is not limited to this, and for example, three-phase alternating current may be used.
  • the method of calculating the effective power is not limited to this, and for example, in the case of three-phase alternating current, it may be calculated by using an arithmetic method such as DQ conversion.
  • the method of detecting the frequency and phase of the AC voltage of the AC system input from the distribution system 24 is not limited to this, and particularly regarding the phase, at the time of new input, the phase advance phase in the discharge direction and the phase advance phase in the charge direction. It suffices if it can be controlled in the slow phase.
  • the governor model in the governor control circuit 40933 is modeled as a first-order lag system, but the present invention is not limited to this. The same effect can be achieved even if the governor model is composed of a second-order lag system or an LPF (Low Pass Filter).
  • the mass point system arithmetic circuit is modeled by an integrator and a feedback loop, but the present invention is not limited to this.
  • the mass point system arithmetic circuit may be modeled by, for example, a first-order lag system, a second-order lag system, an LPF, or the like.
  • the VQ control widely implemented in the virtual synchronous generator control is omitted for the sake of simplicity, but the VQ control is also implemented as the virtual synchronous generator control. The same effect can be obtained by adopting this method for the power conversion device.
  • control circuits of the power conversion device 27 for mega solar and the power conversion device 41 for the distribution system storage battery are hardware as shown in FIGS. 3 to 13.
  • the functions of each block or a part of the blocks described in each block are realized by the software (S / W) mounted on the CPU (Central Processing Unit).
  • S / W Central Processing Unit

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Supply And Distribution Of Alternating Current (AREA)
  • Inverter Devices (AREA)
  • Charge And Discharge Circuits For Batteries Or The Like (AREA)
PCT/JP2020/018323 2020-04-30 2020-04-30 電力変換装置 Ceased WO2021220488A1 (ja)

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CN202080100113.2A CN115428323B (zh) 2020-04-30 2020-04-30 电力变换装置
US17/913,849 US12166427B2 (en) 2020-04-30 2020-04-30 Power conversion device including an inverter control circuit that controls a phase of an AC voltage target value
PCT/JP2020/018323 WO2021220488A1 (ja) 2020-04-30 2020-04-30 電力変換装置
JP2022518561A JP7345644B2 (ja) 2020-04-30 2020-04-30 電力変換装置

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US20210296883A1 (en) * 2020-03-19 2021-09-23 Fuji Electric Co., Ltd. Grid connected inverter, and method for reducing grid frequency variation
JP7537655B1 (ja) * 2024-02-20 2024-08-21 三菱電機株式会社 制御装置及び制御方法

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WO2023275937A1 (ja) 2021-06-28 2023-01-05 三菱電機株式会社 電力変換装置
CN117318136A (zh) * 2023-08-16 2023-12-29 华为数字能源技术有限公司 一种功率变换器、储能供电系统和功率变换器的功率输出方法
WO2025079180A1 (ja) * 2023-10-11 2025-04-17 三菱電機株式会社 分散電源管理装置および配電系統

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WO2025177400A1 (ja) * 2024-02-20 2025-08-28 三菱電機株式会社 制御装置及び制御方法

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US20230115683A1 (en) 2023-04-13
JP7345644B2 (ja) 2023-09-15

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