WO2020204010A1 - 電力変換装置及び発電システム - Google Patents

電力変換装置及び発電システム Download PDF

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Publication number
WO2020204010A1
WO2020204010A1 PCT/JP2020/014703 JP2020014703W WO2020204010A1 WO 2020204010 A1 WO2020204010 A1 WO 2020204010A1 JP 2020014703 W JP2020014703 W JP 2020014703W WO 2020204010 A1 WO2020204010 A1 WO 2020204010A1
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Prior art keywords
voltage
value
power
phase
command value
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Ceased
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PCT/JP2020/014703
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English (en)
French (fr)
Japanese (ja)
Inventor
加藤　修治
良和 ▲高▼橋
哲郎 遠藤
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Tohoku University NUC
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Tohoku University NUC
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Priority to JP2021512143A priority Critical patent/JP7564552B2/ja
Priority to CN202080025935.9A priority patent/CN113678360B/zh
Priority to EP20782339.4A priority patent/EP3952097A4/en
Priority to US17/598,629 priority patent/US11444552B2/en
Publication of WO2020204010A1 publication Critical patent/WO2020204010A1/ja
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0003—Details of control, feedback or regulation circuits
    • H02M1/0025—Arrangements for modifying reference values, feedback values or error values in the control loop of a converter
    • 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
    • H02M7/5387—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 in a bridge configuration
    • H02M7/53871—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 in a bridge configuration with automatic control of output voltage or current
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0003—Details of control, feedback or regulation circuits
    • H02M1/0016—Control circuits providing compensation of output voltage deviations using feedforward of disturbance parameters
    • H02M1/0022—Control circuits providing compensation of output voltage deviations using feedforward of disturbance parameters the disturbance parameters being input voltage fluctuations
    • 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
    • H02M1/14—Arrangements for reducing ripples from DC input or 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
    • 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
    • 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
    • H02M7/5387—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 in a bridge configuration
    • 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
    • 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
    • H02M7/5395—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 by pulse-width modulation
    • 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
    • H02M1/32—Means for protecting converters other than automatic disconnection

Definitions

  • the present invention relates to a power conversion device and a power generation system.
  • Wind power and solar power are attracting attention as renewable energy.
  • the generated DC power is converted into AC power using a power conversion device called a power conditioner and output to the power system.
  • a power conversion device for photovoltaic power generation is provided with a converter, and the generated DC power is supplied to the DC section of the power conversion device, and the DC voltage is shaped into a predetermined AC waveform by the converter.
  • the converter connected to the system via impedance controls the output voltage so that a predetermined difference voltage is generated between the system voltage and the output voltage of the power converter, so that the power generation device generates electricity. Active power can be supplied to the power system.
  • Patent Document 1 the voltage of the electric power system is detected, based on the detected voltage of the electric power system, it is determined whether or not it is a system accident that should be protected and stopped, and when it is determined that the protection should be stopped, the operation is performed.
  • a power converter that shuts down is disclosed.
  • a normal power converter outputs a pulse voltage or a voltage that is a combination of pulse voltages. Therefore, a vibration component (also referred to as a ripple) is superimposed on the output of the power converter. As a result, ripples are also superimposed on the power system.
  • a vibration component also referred to as a ripple
  • ripples are also superimposed on the power system.
  • the time constant of the low-pass filter is set small, the output of the low-pass filter, that is, the detection delay that occurs in the detection voltage is small, but ripples remain in the detection voltage.
  • the time constant of the low-pass filter is set large, the ripple of the detection voltage becomes small, but the detection delay becomes large.
  • Patent Document 1 does not mention removing the ripple of the detected voltage. Therefore, if the time constant is set large and the current flows from the power converter even if the voltage command of the power converter is set to zero, or if the phase of the system voltage is greatly converted, it cannot follow the sudden voltage change. , Overcurrent may flow. Further, the time constant is set small, the ripple is not removed, and there is a possibility that the ripple may erroneously detect whether or not to stop the power conversion device.
  • an object of the present invention is to provide a power conversion device and a power generation system capable of suppressing the ripple of the detected voltage and the detection delay.
  • the power conversion device is a power conversion device connected to a power system via an interconnection impedance, and a switch switches at a predetermined switching cycle to supply power to the power system via the interconnection impedance.
  • the voltage detector Based on the output converter, the voltage detector that detects the voltage at the interconnection point between the power converter and the power system, and the output voltage of the voltage detector that has been moved and averaged for a predetermined period corresponding to the switching cycle.
  • a control device for controlling the converter is a control device for controlling the converter.
  • the power conversion device is a power conversion device connected to a system that functions as an AC voltage source via an interconnection impedance, and has a switch that switches so as to output pulses having different widths at substantially a fixed cycle.
  • a converter that outputs a predetermined AC voltage, a voltage detector that detects the system voltage of the system, and a control device that controls the converter are provided, and the voltage detector is connected to the converter.
  • the power conversion device is a power conversion device connected to a power system via an interconnection impedance, and is a converter that outputs a predetermined AC voltage and a system voltage detection device that detects the system voltage of the power system. And a control device that controls the converter by pulse width modulation control, and the system voltage detection device moves the detected voltage for one cycle or several cycles of the carrier used for the pulse width modulation control.
  • the system voltage is detected by calculating the average, and the control device has a function of calculating the voltage command value of the converter based on the system voltage calculated by the moving average.
  • the power generation system according to the present invention includes the above power conversion device.
  • the ripple of the detected voltage and the detection delay can be suppressed.
  • ripple and detection delay can be further suppressed by calculating the moving average for one cycle of the carrier wave used for pulse width modulation control and detecting the voltage. Further, by calculating the moving average for a period of several cycles of the carrier wave used for pulse width modulation control and detecting the voltage, ripple and detection delay can be further suppressed.
  • FIG. 2A is a schematic view showing a configuration of an interconnection point voltage detection device by analog calculation
  • FIG. 2B is a schematic view showing a configuration of an interconnection point voltage detection device by digital calculation.
  • FIG. 11A is a graph showing the interconnection point voltage detected by the interconnection point voltage detection device calculated by simulation of the power conversion device of the first embodiment
  • FIG. 11B is a graph of the power conversion device of the first embodiment.
  • First Embodiment (1-1) Overall configuration of a power generation system including the power conversion device of the first embodiment of the present invention
  • the case of being used for a power generation system is taken as an example of the first embodiment.
  • the power conversion device will be described.
  • the configuration of the power generation system will be described.
  • the power generation system 100 is connected to an AC voltage source 55 (which is an infinite bus of three-phase AC) via a power system 50.
  • the power system 50 is a system that functions as an AC voltage source.
  • the power generation system 100 includes an active power source 15 and a power conversion device 10, and the active power source 15 is connected to the power conversion device 10 by DC wiring.
  • the active power source 15 is a power generation device such as a wind power generation device or a solar power generation device.
  • the power conversion device 10 is connected to each phase of the power system 50 by terminals LPR, LPS, and LPT (hereinafter, also referred to as interconnection points) via reactors 17R, 17S, and 17T as interconnection impedances.
  • LPR low-power supply
  • LPS low-power supply
  • LPT LPT
  • reactors 17R, 17S, and 17T as interconnection impedances.
  • the configuration of the power conversion device 10 will be described later. In this embodiment, it is assumed that the AC voltage source 55 and the power system 50 have an AC voltage frequency of 50 Hz.
  • the active power source 15 generates DC power and outputs the DC voltage to the power conversion device 10.
  • the power generation system 100 may be a system that generates power by alternating current and converts it into direct current, such as wind power generation, or a battery system that transfers power.
  • a wind power generator is connected to the power conversion device 10 via AC-DC
  • a rechargeable battery such as a secondary battery is used. It is connected to the power converter 10. In this way, the active power source 15 supplies the active power to the power conversion device 10.
  • the power conversion device 10 converts the DC voltage supplied from the active power source 15 into an AC voltage, and outputs the converted AC voltage to the power system 50. As a result, the power conversion device 10 transfers active power and reactive power to and from the AC voltage source 55 via the power system 50. Further, since the power system 50 is composed of electric wires and the like, it actually has an impedance component. Therefore, in FIG. 1, the impedance components 53R, 53S, 53T of each phase of the power system 50 are shown as the resistance components 51R, 51S, 51T and the reactance components 52R, 52S, 52T.
  • the power converter 10 includes a converter 11, reactors 17R, 17S, 17T, an interconnection point voltage detector 20, a control device 30, and a capacitor voltage detector 43. ..
  • the configuration of the control device 30 will be described later.
  • the converter 11 is a converter having a three-phase full bridge circuit configuration.
  • the converter 11 includes an R-phase conversion unit 11R, an S-phase conversion unit 11S, a T-phase conversion unit 11T, a capacitor (DC capacitor) 14, a positive input terminal P, and a negative input terminal N.
  • the converter 11 has an R-phase conversion unit 11R, an S-phase conversion unit 11S, a T-phase conversion unit 11T, and a capacitor 14 connected in parallel between the positive input terminal P and the negative input terminal N.
  • the active power source 15 is connected to the positive input terminal P and the negative input terminal N.
  • the capacitor 14 is a DC capacitor, and the rated voltage of the capacitor 14 is appropriately selected based on the magnitude of the active power and reactive power to be output.
  • the R phase conversion unit 11R In the R phase conversion unit 11R, the S phase conversion unit 11S and the T phase conversion unit 11T, the high side switch 12H and the low side switch 12L are connected in series, the high side switch 12H side is connected to the positive input terminal P, and the low side switch 12L. The side is connected to the negative input terminal N.
  • the R-phase conversion unit 11R is provided with an output terminal 13R at the connection point between the high-side switch 12H and the low-side switch 12L, and the S-phase conversion unit 11S is provided at the connection point between the high-side switch 12H and the low-side switch 12L.
  • the output terminal 13S is provided, and the T-phase conversion unit 11T is provided with the output terminal 13T at the connection point between the high-side switch 12H and the low-side switch 12L.
  • the output terminal 13R of the R phase conversion unit 11R is connected to the u phase of the power system 50 via the reactor 17R and the terminal LPR, and the output terminal 13S of the S phase conversion unit 11S connects the reactor 17S and the terminal LPS. It is connected to the v-phase of the power system 50 via the reactor, and the output terminal 13T of the T-phase conversion unit 11T is connected to the w-phase of the power system 50 via the reactor 17T and the terminal LPT, and is connected to the power system 50.
  • the high side switch 12H and the low side switch 12L are composed of, for example, a switching element made of an IGBT or the like and a freewheeling diode.
  • the positive side of the switching element (collector of the IGBT) and the negative side of the freewheeling diode are connected, and the negative side of the switching element (emitter of the IGBT) and the freewheeling diode are connected.
  • the switching element and the freewheeling diode are connected in antiparallel to the positive side of the device.
  • the IGBT can be protected by allowing a current to flow through the freewheeling diode and preventing a current from flowing from the emitter of the IGBT, which is a switching element, to the collector.
  • the high side switch 12H and the low side switch 12L are, for example, a SiC (silicon carbide) MOS-FET (Metal Oxide Semiconductor Field Effect Transistor: MOS type field effect transistor) or a FET (field effect transistor) made of GaN (gallium nitride). It may be composed of a switching element such as a type transistor) or a FET formed of GaN formed on Si (silicon). These switches are switched to output pulses of different widths at approximately regular intervals.
  • SiC silicon carbide
  • MOS-FET Metal Oxide Semiconductor Field Effect Transistor: MOS type field effect transistor
  • FET field effect transistor
  • GaN gallium nitride
  • the interconnection point voltage detecting device 20 includes a voltage detector (detecting means) 41 and a filtering means 21.
  • the interconnection point voltage detection device 20 detects the voltage of each phase of the power system 50 with the voltage detector 41, and the voltage of each phase detected by the filtering means 21 is moved and averaged for each phase for a predetermined period and then moved and averaged.
  • the voltage is output to the control device 30 as the system voltage of each phase.
  • the configuration of each part of the interconnection point voltage detection device 20 will be described below.
  • the voltage detector 41 is provided at a predetermined location in the power system 50 and detects the voltage at the predetermined location.
  • the voltage detector 41 has an R phase detection unit, an S phase detection unit, and a T phase detection unit (not shown in FIG. 2A), and has an R phase detection unit, an S phase detection unit, and a T phase detection unit.
  • the unit is connected to the interconnection points of the R phase, S phase and T phase of the power converter 10 and the u phase, v phase and w phase of the power system 50 via the measurement terminal 41a, respectively.
  • the measurement terminal 41a is composed of two terminals, one terminal is connected to an interconnection point and the other terminal is connected to a reference potential. One measurement terminal 41a is provided for each phase, but FIG.
  • the voltage detector 41 shows only one measurement terminal 41a for convenience.
  • the R phase detection unit, the S phase detection unit, and the T phase detection unit detect the potentials of the terminals LPR, LPS, and LPT (hereinafter, also referred to as interconnection points) based on the reference potential, respectively.
  • the voltage detector 41 detects the voltage at the interconnection point.
  • the voltage detected by the voltage detector 41 is a voltage with the AC neutral point as a reference potential, and is a voltage corresponding to the phase voltage of each phase of the power system 50.
  • the voltage detection is not limited to the above, and the line voltage may be detected.
  • the filtering means 21 performs a moving average of the output of the voltage detector 41 for the purpose of removing the ripple component accompanying the switching of the converter 11.
  • the moving average may be performed only by the filtering means 21 or may be performed in combination with the subsequent control device 30. Further, the filtering means 21 may calculate an approximate value of the moving average.
  • the approximate value means a value including an error, for example, when the window (period) of the moving average is not an integral multiple of the calculation cycle of the control device and includes some error (for example, ⁇ 3%). Even in such a case, it is possible to operate the power conversion device, although the operating performance is slightly lowered.
  • the filtering means 21 When each switching of the converter 11 is driven by PWM (pulse width modulation) control of a triangular wave comparison method, the simplest embodiment of the filtering means 21 is to integrate the output of the voltage detector 41 with an analog circuit. Is preferable. For example, as shown in FIG. 2A, the moving average can be calculated by integrating with an integrator circuit using an operational amplifier or the like.
  • the filtering means 21 shown in FIG. 2A is composed of a two-terminal input terminal 21a, a resistor 21b, a capacitor 21c, a two-terminal output terminal 21d, and an operational amplifier 21e.
  • One of the input terminals 21a is connected to the negative terminal of the operational amplifier 21e via a resistor 21b, and the other of the input terminals 21a is connected to one of the positive terminal and the output terminal 21d of the operational amplifier 21e.
  • the output of the operational amplifier 21e is connected to the other of the output terminals 21d and is fed back to the negative terminal of the operational amplifier via the capacitor 21c.
  • the filtering means 21 is configured in the integrating circuit, and the moving average is calculated by integrating the detected voltage.
  • the filtering means 21 has one such integrating circuit for each phase, but only one is shown in FIG. 2A for convenience.
  • the resistance value of the resistor 21b, the capacitance value of the capacitor 21c, the gain of the operational amplifier 21e, and the like may be appropriately set in consideration of the ripple frequency and the like.
  • the capacitor voltage detector 43 is connected to both ends of the capacitor 14 and detects the capacitor voltage of the capacitor 14. The capacitor voltage detector 43 outputs the detection result to the control device 30.
  • the power conversion device 10 outputs a voltage component output by feed forward of the interconnection point voltage V, a voltage component output based on the active power component voltage command value, and an ineffective power component voltage command value. Outputs the sum voltage with the voltage component. Since the operation of the power conversion device 10 is the same for the R phase, the S phase, and the T phase, the R phase will be described as a representative.
  • a gate pulse signal is input from the gate pulse generation unit 37 (see FIG. 3) to the high side switch 12H and the low side switch 12L of the R phase conversion unit 11R. Specifically, for example, a predetermined voltage is input to the gate of the IGBT constituting the high side switch 12H and the low side switch 12L.
  • the R phase conversion unit 11R of the R phase conversion unit 11R A positive capacitor voltage is output to the output terminal 13R.
  • the R phase conversion unit 11R is the R phase conversion unit. A negative capacitor voltage is output to the output terminal 13R of 11R.
  • the converter 11 converts the DC voltage of the capacitor 14 into an AC voltage by switching the on / off of the high side switch 12H and the low side switch 12L of the R phase conversion unit 11R, and u of the power system 50. Outputs AC voltage to the phase.
  • the converter 11 outputs a three-phase AC voltage by controlling each phase so as to output an AC voltage whose phases are 120 degrees out of phase with each other to the power system 50 by the same method.
  • the configuration of the converter 11 is not particularly limited as long as it can convert the input DC voltage into a three-phase AC voltage and output it to the power system, and is a multi-level such as MMC (Modular Multilevel. Converter). It may be a converter or a three-level converter capable of outputting a predetermined three-level voltage, particularly a so-called NPC three-level converter.
  • MMC Modular Multilevel. Converter
  • the interconnection point voltage detection device (voltage detection device) 20 detects the system voltage of the system that functions as an AC voltage source. Specifically, the interconnection point voltage detection device 20 detects the voltage at the interconnection point, that is, the interconnection point voltage V, as the system voltage of the power system 50.
  • the voltage detector 41 detects the voltage of the interconnection points LPR, LPS, and LPT of each phase, and outputs the detected voltage of each phase from the detection terminal 41b to the filtering means 21.
  • the filtering means 21 integrates the detection voltage of each phase input from the input terminal 21a for each phase by the integrator circuit.
  • the filtering means 21 calculates the moving average by integrating the detected voltage over time.
  • the filtering means 21 outputs the moving average result as the interconnection point voltage V of each phase from the output terminal 21d to the control device 30. In this way, the voltage at the interconnection point of each phase is detected, and the detected voltage is moved and averaged by time integration, so that the interconnection point voltage V of each phase is detected.
  • the filtering means 21 filters the interconnection point voltage V by moving average the output voltage of the voltage detector 41 for a predetermined period.
  • the control device 30 detects the current value of the interconnection point voltage V (result of the moving average) and the sequence detected one cycle before the triangular wave (carrier wave) of PMW.
  • the difference from the past value of the system point voltage V is taken, and the magnitude of the difference value is appropriately adjusted (gain adjustment).
  • gain adjustment By taking the difference between the current value and the past value of the interconnection point voltage V, the period between the time when the past value is detected and the present corresponds to the period of the moving average, and the difference value is the sequence detected in that period. It is the average value of the system point voltage V.
  • the moving average for one cycle of the carrier wave (one cycle of the fixed cycle), which is a wave that fluctuates at a fixed cycle used for pulse width control, is calculated.
  • this work may be performed by the interconnection point voltage detection device 20, and the difference value may be output as the interconnection point voltage V.
  • the moving average can be obtained not by such analog calculation but by digital calculation as shown below.
  • the interconnection point voltage detection device 25 shown in FIG. 2B is used.
  • the interconnection point voltage detection device 25 includes a voltage detector 41 and a filtering means 26. Since the configuration of the voltage detector 41 is the same, the description thereof will be omitted.
  • the filtering means 26 is composed of a memory 27 and a calculation unit 28, and filters by moving averaging the output voltage of the voltage detector 41 for a predetermined period.
  • the memory 27 stores the detection voltage of each phase detected by the voltage detector 41 for a predetermined period of time.
  • the memory 27 is a known storage device such as a DRAM, SRAM, flash memory, and hard disk drive.
  • the calculation unit 28 calculates the average value of the detection voltages stored in the memory 27 for each phase, and outputs the calculation result to the control device 30 as the interconnection point voltage V of each phase.
  • the calculation unit 28 may be dedicated hardware for calculating the average value of the detected voltage, may be realized by a general-purpose processor and embedded software, or may be realized by a program using a PC.
  • the voltage detector 41 detects the voltage of the interconnection points LPR, LPS, and LPT of each phase, and outputs the detected voltage to the filtering means 26.
  • the memory 27 sequentially stores the input detection voltage, and is used for one cycle of the triangular wave (carrier wave), which is a wave that fluctuates at a fixed cycle used for PWM control of the triangular wave comparison method in the control device 30 described later. Hold memory for a period of time.
  • the memory 27 sequentially erases the detected voltage holding the memory after the detection voltage has passed for one cycle. That is, in the memory 27, the stored detection voltage is updated with the passage of time, and the memory 27 stores the detection voltage detected between the present and the period before one cycle of the carrier wave.
  • the calculation unit 28 reads out all the detection voltages stored in the memory 27, calculates the average value of the read detection voltages, and outputs the calculated average voltage to the control device 30 as the interconnection point voltage V. Since the memory 27 stores the detection voltage detected during the period from the present to one cycle before the carrier, and the detection voltage is updated with the passage of time, the memory 27 stores the detection voltage in the calculation unit 28. By reading out all the detected voltages and calculating the average value of the detected voltages, the moving average of the detected voltages is calculated in the period of one cycle of the carrier.
  • the configuration of the interconnection point voltage detection devices 20 and 25 is not particularly limited as long as the moving average of the detection voltage can be calculated or a part of the calculation can be performed.
  • the control device 30 controls the on / off state of each switch of the converter 11 based on the interconnection point voltage V and the like detected in this way, and controls the output voltage of the converter 11.
  • the output voltage of the converter 11 is controlled by feedforwarding the interconnection point voltage V detected by performing the moving average to the voltage command value. If the interconnection point voltage V detected by the moving average is fed forward as it is, that is, if PWM of the triangular wave comparison method is performed using the interconnection point voltage V, the converter 11 ideally has an interconnection point. Since the same voltage as the voltage V is output, robustness against voltage fluctuation can be ensured to some extent. In particular, the robustness against voltage fluctuations when the current is zero is extremely high. However, since a signal delay occurs due to the moving average, it is preferable that each switching frequency of the converter 11 is high in order to reduce the signal delay. Therefore, it is preferable to use a switching element having a high switching frequency for each switch of the converter 11.
  • the control device 30 includes an ineffective power component voltage command value generation unit 31, a current calculation unit 32, an active power component current command value generation unit 33, and an active power component voltage command value generation unit 34.
  • a gain control unit 35, a voltage command value generation unit (voltage command value generation means) 36, and a gate pulse generation unit 37 are provided.
  • the reactive power component voltage command value generation unit 31 is composed of a multiplier having a gain of q (real number).
  • the current calculation unit 32 is composed of a divider that divides by the interconnection impedance value.
  • the active power component current command value generation unit 33 is composed of a multiplier having a gain of d (real number).
  • the active power component voltage command value generation unit 34 uses the active power component current command value as a differential calculation means. L ⁇ (dI / dt) + RI ⁇ ⁇ ⁇ (1) It is configured to perform the calculation of the equation (1).
  • the active power component voltage command value generation unit 34 is configured by combining an arithmetic circuit capable of calculating the above equation, for example, a differentiator or an adder.
  • the voltage command value generation unit 36 is composed of an adder.
  • the gate pulse generation unit 37 is configured to generate a gate pulse signal that controls on / off of each switch of the converter 11 by known PWM control.
  • the gain control unit 35 is configured to control the value of the gain d of the active power component current command value generation unit 33 and the value of the gain q of the reactive power component voltage command value generation unit 31.
  • the control device 30 adds a voltage whose phase is advanced by 90 degrees with respect to the interconnection point voltage for outputting the effective voltage and a voltage having the same phase as the interconnection point voltage for outputting the invalid voltage.
  • the interconnection point voltage V is fed forward to calculate the voltage command value Vpp, and the output voltage of the converter 11 is controlled based on the voltage command value Vpp. The operation will be specifically described below.
  • the interconnection point voltage V detected by the interconnection point voltage detection device 20 is the reactive power component voltage command value generation unit 31, the current calculation unit 32, the gain control unit 35, and the voltage command value generation unit. It is input to 36.
  • the reactive power component voltage command value generation unit 31 generates the reactive power component voltage command value Vqp by multiplying the input detection value of the interconnection point voltage V by q, and outputs the reactive power component voltage command value Vqp to the voltage command value generation unit 36.
  • the current calculation unit 32 divides the detected value of the interconnection point voltage V by the interconnection impedance value, that is, the value of the reactor 17R ( ⁇ L, ⁇ is the frequency of the interconnection point voltage V, L is the inductance value of the reactor 17).
  • the detected value of the interconnection point voltage V is converted into a current value, and the converted current value is output to the active power component current command value generation unit 33. Since the resistance component of the reactor 17R is ideally 0, the resistance component of the reactor 17R is ignored in the present embodiment.
  • the active power component current command value generation unit 33 generates the active power component current command value by multiplying the input current value by d.
  • the active power component current command value generation unit 33 outputs the active power component current command value to the active power component voltage command value generation unit 34.
  • the active power component voltage command value generation unit 34 performs the calculation of the above equation (1) on the active power component current command value, converts the current command value calculated from the interconnection point voltage into a voltage command value, and is effective.
  • the power component voltage command value Vdp is calculated and output to the voltage command value generation unit 36. Since the resistance component of the reactor 17 is ideally 0, in the present embodiment, the resistance component of the reactor 17 is set to zero.
  • equation (1) is an equation for calculating the voltage drop in the reactor from the current flowing through the reactor, and is the product of the resistance component of the reactor and the current in the value obtained by time-differentiating the current and multiplying it by the inductance value of the reactor.
  • the phase of the voltage value (active power component voltage command value Vdp) calculated by the equation (1) is 90 degrees ahead of the current value (active power component current command value) used in the calculation.
  • the active power component voltage command value Vdp is advanced by 90 degrees with respect to the interconnection point voltage V having the same phase as the active power component current command value.
  • the control device 30 differentiates the interconnection point voltage V to obtain a voltage (active power component voltage command value Vdp for outputting active power) whose phase is 90 degrees ahead of the interconnection point voltage V. It has a function to calculate.
  • the difference in time from the previous control cycle and the difference in the active power component current command value are calculated, and the difference in the active power component current command value is divided by the time difference to obtain the active power.
  • the differential value of the component current command value may be calculated.
  • the voltage command value generation unit 36 adds the input detection value of the interconnection point voltage V, the reactive power component voltage command value Vqp, and the active power component voltage command value Vdp to generate the voltage command value Vpp.
  • the control device 30 has a function of calculating the voltage command value Vpp of the converter 11 based on the system voltage calculated by the moving average.
  • the voltage command value generation unit 36 outputs the generated voltage command value Vpp to the gate pulse generation unit 37.
  • the gate pulse generation unit 37 generates a carrier wave (for example, a triangular wave) for PWM control, and modulates the input voltage command value Vpp with the carrier wave.
  • the gate pulse generation unit 37 generates a gate pulse signal by standardizing the voltage command value Vpp and comparing the standardized voltage command value Vpp with the carrier wave.
  • the gate pulse generation unit 37 generates a gate pulse signal that controls on / off of the high side switch 12H and the low side switch 12L of the R phase conversion unit 11R of the converter 11 by modulating the voltage command value Vpp with the carrier wave.
  • the gate pulse generation unit 37 outputs the generated gate pulse signal to the switch. In this way, the control device 30 controls the on / off of the high side switch 12H and the low side switch 12L of the R phase conversion unit 11R.
  • the gain control unit 35 controls the value of the gain d of the active power component current command value generation unit 33 and the value of the gain q of the reactive power component voltage command value generation unit 31.
  • the gain control unit 35 detects the interconnection point voltage V detected by the interconnection point voltage detection device 20, the frequency of the power system 50 (AC voltage source 55) calculated from the interconnection point voltage V, and the capacitor voltage detector 43.
  • the values of the gain q and the gain d are determined based on the capacitor voltage of the capacitor 14 of the converter 11 and the ineffective power and the active power output by the power converter 10 are controlled.
  • the gain control unit 35 increases the value of the gain d and increases the active power output by the power conversion device 10, so that the active power flowing into the power conversion device 10 from the active power source 15 and the electric power The active power flowing out from the conversion device 10 to the power system 50 is balanced.
  • the capacitor voltage is reduced by making the active power flowing out from the power conversion device 10 to the power system 50 smaller than the active power flowing into the power conversion device 10 from the active power source 15. Can be raised.
  • the gain control unit 35 reduces the value of the gain d and reduces the active power output by the power conversion device 10, so that the active power flowing into the power conversion device 10 from the active power source 15 and the electric power The active power flowing out from the conversion device 10 to the power system 50 is balanced.
  • the gain control unit 35 increases the value of the gain q, and the interconnection point voltage V, that is, the system voltage. To raise.
  • the gain control unit 35 reduces the value of the gain q and lowers the system voltage.
  • the gain control unit 35 increases the value of the gain d to increase the amount of active power supplied to the power system 50.
  • the gain control unit 35 reduces the value of the gain d, reduces the amount of active power supplied to the power system 50, and reduces the frequency.
  • the gain control unit 35 sets the value of the gain d to a negative real number, and causes the active power to flow from the power system 50 into the power conversion device 10.
  • the power conversion device 10 of the first embodiment is connected to the power system 50 via interconnection impedance (reactors 17R, 17S, 17T), and has a predetermined AC voltage.
  • the converter 11 is controlled by a system voltage detection device (interconnection point voltage detection device 20) that detects the system voltage (interconnection point voltage V) of the power system 50, and a pulse width modulation control.
  • a control device 30 is provided, and the interconnection point voltage detection device 20 calculates a moving average of the detected voltage (detection voltage detected by the voltage detector 41) for one cycle of the carrier used for pulse width control.
  • the interconnection point voltage V was detected in the above, and the control device 30 was configured to calculate the voltage command value of the converter 11 based on the interconnection point voltage V calculated by the moving average.
  • the power conversion device 10 of the first embodiment calculates the moving average of the detection voltage detected by the interconnection point voltage detection device 20 in the voltage detector 41 for one cycle of the carrier wave used for pulse width control. As a result, the interconnection point voltage V is detected, so that the ripple and detection delay of the detected voltage can be suppressed. Therefore, even when a phase jump occurs in the power system 50, the output voltage of the power conversion device 10 can follow the fluctuation of the voltage of the power system 50, and the overcurrent can be suppressed from flowing through the power conversion device 10.
  • the power conversion device 10 of the first embodiment is configured to calculate the active power component voltage command value by time-differentiating the detected interconnection point voltage V, thereby obtaining the active power component voltage command value. It can be calculated quickly, and the flow of overcurrent to the power conversion device 10 can be further suppressed.
  • the interconnection point voltage as the system voltage of the power system detected by the interconnection point voltage detection device as the system voltage detection device is treated as the current command value.
  • the effective current command value is calculated as a real multiple of the interconnection point voltage, and the effective voltage command value (active power component voltage) is calculated from the effective current command value. (Command value) is calculated.
  • the effective current command value is determined with the interconnection point voltage as the current command value 1pu.
  • the effective current command value is determined with the interconnection point voltage as the current command value of 1pu for easy explanation.
  • the effective current command value is a value proportional to the interconnection point voltage, it does not necessarily have to be 1 pu.
  • the effective current command value (pu value) is 0.2 pu
  • the product of the interconnection point voltage and 0.2 is the effective current command value.
  • the reactive current command value the current command value of 1 pu is obtained by shifting the phase of the interconnection point voltage by 90 degrees. Similar to the active current command value, the reactive current command value is determined by multiplying the voltage shifted by 90 degrees from the interconnection point voltage by a real number (multiplier the reactive current command value (pu value)). In this way, the value obtained by multiplying the interconnection point voltage V by the real number is set as the current command value.
  • the configuration of the control device is different from the configuration of the control device 30 of the power conversion device 10 of the first embodiment. Since other configurations are the same as those of the power conversion device 10 of the first embodiment, the description thereof will be omitted.
  • FIG. 4 is a diagram showing a control device 4000 of the power conversion device of the second embodiment.
  • the control device 4000 includes a phase compensation block 4100, a 90-degree phase lead calculation block 4200, an invalid component calculation block (invalid component calculation means) 4300, an effective component calculation block (effective component calculation means) 4400, and a voltage command value generation. It is composed of a block 4001 (voltage command value generating means) and a PWM block 4500. The operation of such a control device 4000 will be described below.
  • the detected interconnection point voltage V is smoothed via the interconnection point voltage detection device 20 and then taken into the control device 4000.
  • the signal of the interconnection point voltage V taken into the control device 4000 is input to the phase compensation block 4100.
  • the output of the phase compensation block 4100 is input to the effective component calculation block 4400, the 90-degree phase lead calculation block 4200, and the voltage command value generation block 4001.
  • the integrated result of the multiplier 4401 is the current converter. It is converted to the effective current command effective value Iref_dr at 4402.
  • the effective current command effective value Iref_dr is input to the voltage estimation unit 4403, and it is necessary to apply the effective current command effective value Iref_dr to the interconnection impedance (reactor) in order to allow the current to flow.
  • a certain voltage value (effective component voltage estimated value Vi_d) is estimated, and the estimation result is output to the voltage command value generation block 4001 as an effective voltage command value.
  • the voltage estimation unit 4403 as a differential calculation means time-differentiates the effective current command effective value Iref_dr calculated from the interconnection point voltage V, and differentiates the effective current command effective value Iref_dr and the inductance of the interconnection impedance.
  • the effective component voltage estimated value Vi_d is estimated by adding the product of the values and the product of the effective current command effective value Iref_dr and the resistance value of the interconnection impedance.
  • phase of the interconnection point voltage V input from the phase compensation block 4100 is advanced by 90 degrees by rotating the phase by 90 degrees using a rotation matrix, and the invalid component calculation is performed.
  • the reactive component calculation block 4300 after the output of the reactive calculation block and the reactive power command value (pu value) are integrated by the multiplier 4301, the output of the multiplier 4301 is the reactive current command effective value by the current converter 4302. Converted to Iref_qr.
  • the reactive current command effective value Iref_qr is input to the voltage estimation unit 4303, and the reactive current command effective value Iref_qr needs to be applied to the interconnection impedance (reactor) in order to allow the current to flow.
  • a certain voltage value (reactive component voltage estimated value Vi_q) is estimated, and the estimation result is output to the voltage command value generation block 4001 as a reactive voltage command value (reactive power component voltage command value).
  • the voltage estimation unit 4303 as a differential calculation means differentiates the reactive current command effective value Imped_qr calculated from the interconnection point voltage V whose phase is advanced by 90 degrees, and differentiates the reactive current command effective value Imped_qr.
  • the control device has a function of calculating the reactive power component voltage command value and the active power component voltage command value by time-differentiating the interconnection point voltage V.
  • the phase-compensated interconnection point voltage V input from the phase compensation block 4100 and the effective voltage command value input from the effective component calculation block 4400 are used.
  • the invalid voltage command value input from the invalid component calculation block 4300 is added, and the voltage command value of the power conversion device is generated.
  • the control device 4000 has a function of calculating the voltage command value of the converter based on the system voltage calculated by the moving average.
  • the voltage command value is input to the PWM block 4500 and standardized in the PWM block 4500.
  • the standardized voltage command value is modulated by the PWM control of the triangular wave comparison method to generate the gate pulse of each switch of the converter, and the gate pulse is output to each switch to drive each switch. ..
  • the phase compensation block 4100 compensates for the phase of the interconnection point voltage V delayed by smoothing with the interconnection point voltage detection device 20. Specifically, the phase of the input interconnection point voltage V is advanced by the phase delayed by the interconnection point voltage detection device 20. More specifically, it is preferable to advance the phase portion corresponding to the time of half the period for calculating the moving average. As a means for advancing the phase, as in the 90-degree phase advance calculation block 4200 described later, after three-phase two-phase conversion, the phase component phase is advanced by a rotation matrix to perform two-phase three-phase conversion. It is preferable to include the phase compensation block 4100, but it may not be provided.
  • the 90-degree phase lead calculation block 4200 converts the interconnection point voltage V of each phase input from the phase compensation block 4100 into three-phase / two-phase conversion by the three-phase / two-phase conversion unit 4201, and the three-phase / two-phase conversion is performed.
  • the point voltage V is advanced by 90 degrees in the rotation matrix by the phase rotating unit 4202.
  • the 90-degree phase advance calculation block 4200 converts the interconnection point voltage V whose phase is advanced by 90 degrees into two-phase and three-phase by the two-phase three-phase conversion unit 4203, and the interconnection point voltage V of each phase whose phase is advanced by 90 degrees. Is output to the invalid portion calculation block 4300.
  • the 90-degree phase advance calculation block 4200 may delay the 90-degree phase. However, in this case, the sign of the reactive current command value is opposite.
  • the current conversion unit 4302 and the current conversion unit 4402 divide the voltage value (output of the multiplier 4301 or the multiplier 4401) by the phase voltage rated voltage and convert it into the current rated value amp value, and the effective current command effective value Iref_dr is invalid.
  • the current command effective value Iref_qr is calculated.
  • the voltage estimation unit 4303 and the voltage estimation unit 4403 calculate the effective component voltage estimated value Vi_d from the active current command effective value Iref_dr, and calculate the reactive current command effective value Iref_qr and the reactive component voltage estimated value Vi_q. This calculation is performed by an instantaneous formula such as the following formulas (2) and (3).
  • Vi_d (Ls + R) ⁇ Iref_dr ...
  • Vi_q (Ls + R) ⁇ Iref_qr ... (3)
  • L is the inductance value of each phase
  • R is the resistance value of the reactor of each phase
  • s is the Laplace operator.
  • the effective current command effective value Iref_dr (invalid current command effective value Iref_qr) is differentiated and the inductance value L is multiplied, and the product of the effective current command effective value Iref_dr (invalid current command effective value Iref_qr) and the resistance value is added to the multiplication result.
  • the effective component voltage estimated value Vi_d (ineffective component voltage estimated value Vi_q) is calculated.
  • the invalid component calculation block 4300 outputs the calculated invalid component voltage estimated value Vi_q as an invalid voltage command value to the voltage command value generation block 4001, and the effective component calculation block 4400 outputs the calculated effective component voltage estimated value Vi_d to the effective voltage command. It is output as a value to the voltage command value generation block 4001.
  • the power conversion device of the second embodiment has the same configuration as the power conversion device of the first embodiment, and the control device 4000 has an interconnection point voltage V calculated by a moving average.
  • the voltage command value of the converter 11 was calculated based on the above.
  • the power conversion device of the second embodiment detects the interconnection point voltage V by calculating the moving average of the period for one cycle of the carrier wave used for the pulse width control, as in the first embodiment. Since the point voltage detection device 20 is provided, ripple of the detected voltage and detection delay can be suppressed. Therefore, even when a phase jump occurs in the power system, the output voltage of the power conversion device can follow the fluctuation of the voltage of the power system, and the overcurrent can be suppressed from flowing to the power conversion device.
  • the power conversion device of the second embodiment has high robustness against phase jump by configuring the control device 4000 to set a current command and calculate the required voltage from the instantaneous type.
  • a limiter block is provided after the invalid portion calculation block 4300 and the effective portion calculation block 4400, and when the outputs of the invalid portion calculation block 4300 and the effective portion calculation block 4400 are out of the predetermined range, the limiter block is preset. Output the limiter value.
  • the limiter value is the same as the voltage (both positive and negative) applied to the interconnection impedance when the rated current flows through the interconnection impedance, or the degree to which a slight margin is provided, for example, 1 of the voltage. It is preferably around 5.5 times.
  • the detected interconnection point voltage V is passed through a notch filter or a filter that attenuates frequencies that are integral multiples of a predetermined frequency
  • high-order harmonics for example, It is preferable that the detected interconnection point voltage V is passed through a low-pass filter to attenuate the harmonics superimposed on the interconnection point voltage V, and the harmonics superimposed on the current command value are attenuated. Harmonics may be attenuated by filtering the effective current command effective value and the reactive current command effective value.
  • the low-pass filter is used as a countermeasure against inexact differential calculation and harmonics by the above equations (4) and (5), a phase delay occurs in the effective voltage command value and the invalid voltage command value.
  • the reactive current command value when passing an active current from the power converter, it is preferable to slightly increase the reactive current command value and add the reactive current to the active current to compensate for the phase lag.
  • the active current means the current for the power converter to output the active power
  • the invalid current means the current for the power converter to output the invalid current, both of which are the currents output by the power converter. It is an ingredient.
  • FIG. 5 is an enlarged view showing a part of the control device of the modified example 4, and corresponds to the region surrounded by the alternate long and short dash line in the control device 4000 shown in FIG. Since the configuration of the control device other than the region shown in FIG. 5 is the same as that of the second embodiment, the description thereof will be omitted.
  • both blocks cannot be completely separated and both blocks interfere with each other.
  • the reactive current command effective value Iref_qr of each phase converted from the reactive current command value by the current conversion unit 4302 is the each phase calculated by the voltage compensation value calculation block described later in the multiplier 4309. The same phases as the voltage compensation value of are multiplied by each other, and the voltage fluctuation is compensated.
  • the reactive current command effective value Iref_qr compensated for the voltage fluctuation is output to the filter block 4305, and the harmonics are attenuated.
  • the filter block 4305 is composed of, for example, a low-pass filter.
  • the reactive current command effective value Iref_qr with the harmonics attenuated is added by the multiplication unit 4307 and the current for phase delay compensation in the filter block 4305 calculated by multiplying the active current command effective value Iref_dr by the real number ⁇ with the multiplier 4406. Is input to the voltage estimation unit 4303. Then, in the voltage estimation unit 4303, the reactive component voltage estimation value Vi_q, which is the voltage of the interconnection impedance required to pass the current corresponding to the reactive current command effective value Iref_qr to which the current for phase delay compensation is added, is described above. It is calculated by the equation (5) and output as a reactive voltage command value.
  • the formula (3) may be used instead of the formula (5).
  • a limiter block 4308 is provided between the voltage estimation unit 4303 of the invalid component calculation block 4300a and the voltage command value generation block 4001, and the voltage estimation section 4403 and the voltage command value generation block 4001 of the effective component calculation block 4400a are provided.
  • a limiter block 4408 is provided between the two. In these limiter blocks 4308 and 4408, it is preferable that the limiter value is a value in which the minimum value and the maximum value of the voltage applied to the interconnection impedance at the time of passing the rated current have a necessary margin.
  • the limiter block 4038 when the invalid voltage command value input from the voltage estimation unit 4303 is within the predetermined range, the invalid voltage command value is output to the voltage command value generation block 4001 as it is, and the invalid voltage command value is out of the predetermined range.
  • the preset limiter value is output to the invalid component calculation block 4300a, that is, the voltage command value generation block 4001 is output as the invalid voltage command value.
  • the reactive current command effective value Iref_qr whose harmonics are attenuated by the filter block 4305 is multiplied by a real number ⁇ by the multiplier 4306, and is effective as a current for phase delay compensation in the filter block 4405. It is output to the minute calculation block 4400a.
  • the effective current command effective value Iref_dr of each phase converted from the effective current command value by the current conversion unit 4402 is the each phase calculated by the voltage compensation value calculation block described later by the multiplier 4409. The same phases as the voltage compensation value of are multiplied by each other, and the voltage fluctuation is compensated.
  • the effective current command effective value Iref_dr in which the voltage fluctuation is compensated is output to the filter block 4405, and the harmonics are attenuated.
  • the filter block 4405 is composed of, for example, a low-pass filter.
  • the active current command effective value Iref_dr with the harmonics attenuated is calculated by multiplying the reactive current command effective value Iref_qr by a real number ⁇ with the multiplier 4306, and the current for phase delay compensation in the filter block 4305 is added by the multiplication unit 4407. , Is input to the voltage estimation unit 4403. Then, in the voltage estimation unit 4403, the effective component voltage estimation value Vi_d, which is the voltage of the interconnection impedance required to pass the current corresponding to the effective current command effective value Iref_dr to which the current for phase delay compensation is added, is described above. It is calculated by the equation (4) and output to the limiter block 4408 as an effective voltage command value.
  • the equation (2) may be used instead of the equation (4).
  • the effective voltage command value when the effective voltage command value is within a predetermined range, the effective voltage command value is output to the voltage command value generation block 4001 as it is, and when the effective voltage command value deviates from the predetermined range, a preset limiter is used.
  • the value is output to the effective portion calculation block 4400a, that is, the voltage command value generation block 4001 as the effective voltage command value.
  • the effective current command effective value Iref_dr whose harmonics are attenuated by the filter block 4405 is multiplied by the real number ⁇ by the multiplier 4306, and is invalid as the current for phase delay compensation in the filter block 4305. It is output to the minute calculation block 4300a.
  • the phase-compensated interconnection point voltage V input from the phase compensation block 4100 and the effective voltage command value input from the effective component calculation block 4400 are invalid.
  • the invalid voltage command value input from the minute calculation block 4300 is added to generate the voltage command value of the power conversion device.
  • FIG. 6 shows a voltage compensation value calculation block (voltage compensation value calculation) for calculating a voltage compensation value for compensating for a current command value (reactive current command effective value, effective current command effective value) when the voltage fluctuates in a steady state. Means) 4700 is shown. In the voltage compensation value calculation block 4700, the voltage compensation value of each phase (u phase, v phase and w phase) is calculated. Since the calculation operation of the voltage compensation value is the same for each phase, the u phase will be described below as a representative.
  • the detection value of the u-phase interconnection point voltage V smoothed by the interconnection point voltage detection device 20 is input, and the square value of the interconnection point voltage is calculated by the multiplier 4701. To.
  • the squared value of the interconnection point voltage is output to the 1/4 cycle delay unit 4702 and the adder 4703.
  • the 1/4 cycle delay unit 4702 is composed of, for example, a memory.
  • the 1/4 cycle delay unit 4702 holds the square value of the interconnection point voltage V in the memory for a period of 1/4 cycle, and after 1/4 cycle elapses, 1/4 of the square value of the interconnection point voltage V. It is output to the adder 4703 as a past value before the cycle.
  • the adder 4703 is a past value of the square value (current value) of the interconnection point voltage V input from the multiplier 4701 and the square value of the interconnection point voltage V input from the 1/4 cycle delay unit 4702. And are added and output to the route calculation unit 4704.
  • the route calculation unit 4704 calculates the route of the output of the adder 4703 and outputs it to the divider 4705.
  • the divider 4705 divides the output of the route calculation unit 4704 by ⁇ 2. This division result is a value corresponding to the effective value of the u-phase interconnection point voltage V.
  • the divider 4705 outputs the division result to the u-phase voltage compensation value calculation unit 4706 as an effective value of the interconnection point voltage V.
  • the value of the rated phase voltage of the u phase is also input to the u-phase voltage compensation value calculation unit 4706.
  • the u-phase voltage compensation value calculation unit 4706 calculates the u-phase voltage compensation value by dividing the rated voltage of the u-phase by the effective value of the interconnection point voltage V of the u-phase.
  • the limiter inserts a limiter block having the same configuration as the above-mentioned limiter block 4308 (the limiter value is different) between the voltage compensation value calculation block 4700 and the multiplier 4309 or between the voltage compensation value calculation block 4700 and the multiplier 4409. It can be carried out by doing.
  • the voltage compensation calculation (calculation with the multipliers 4309 and 4409) is put in the previous stage of the differential calculation (calculation with the voltage estimation unit 4303 and 4403) as in the modification 4, switching with or without voltage fluctuation compensation.
  • the voltage compensation calculation it is preferable to put the voltage compensation calculation in the subsequent stage of the differential calculation.
  • insert a multiplication means such as a multiplier between the voltage compensation value calculation block 4700 and the multipliers 4309 and 4409 so that the voltage compensation is not suddenly stopped. It is necessary to take measures to reduce the gain of the multiplication means.
  • the power converter of the third embodiment feeds back the current output by the power converter to the power converter of the second embodiment to control the output of the power converter. It was done. This current feedback control will be described below.
  • the active current is fed back to control the active power output by the power converter
  • the reactive current is fed back to control the reactive power output by the power converter.
  • the instantaneous active power may be fed back when controlling the active power
  • the instantaneous reactive power may be fed back when controlling the reactive power. This is because in three-phase equilibrium, the instantaneous active power is the three-phase sum of the product of the active current and the interconnection point voltage V, and the instantaneous reactive power is the three-phase sum of the product of the reactive current and the interconnection point voltage V. This is because the active current and the instantaneous reactive power are proportional, and the reactive current and the instantaneous reactive power are also proportional.
  • a subtractor for calculating is provided. Then, the instantaneous active power and the instantaneous reactive power output from the instantaneous power calculation block are multiplied by a predetermined gain with a multiplier to adjust the magnitude, and the difference between the active current command value and the instantaneous reactive power is invalidated with the subtractor.
  • the difference between the current command value and the instantaneous reactive power is calculated, the instantaneous active power is fed back to the active current command value, and the instantaneous reactive power is fed back to the reactive current command value. This operation corresponds to current feedback control.
  • the power conversion device of the third embodiment has the same configuration as that of the second embodiment, it has the same effect, and further feeds back the current (active power or ineffective power) as described above to output the output of the power converter.
  • the current output by the power converter that is, active power or ineffective power
  • the current output by the power converter can be controlled more accurately.
  • the power conversion device 10a of the fourth embodiment is used in the power generation system 100a as in the first embodiment.
  • the power conversion device 10a is different from the power conversion device 10 of the first embodiment in that it includes a control device 60 that performs vector control. More specifically, unlike the control device 30 (see FIG. 3) of the first embodiment, the control device 60 is a vector control means for calculating the voltage command value of the converter 11 by vector control based on the system voltage. Is. Since the configuration other than the control device 60 is the same as that of the power conversion device 10 of the first embodiment, the description thereof will be omitted.
  • the control device 60 uses a known vector control method and converts based on the interconnection point voltage as the system voltage of the power system 50. Generates the voltage command value of the device 11.
  • the control device 60 will be described as a control device to which the vector control method disclosed in Japanese Patent No. 4373040 is applied.
  • the control device 60 Since the control device of the self-excited converter is required to have high-speed control, it is generally composed of a non-interference vector control system by converting a three-phase alternating current into a two-phase direct current component of an active component and an ineffective component by dq conversion. As shown in FIG. 8, the control device 60 includes an effective current command generation unit 61d, an invalid current command generation unit 61q, a phase detection unit 68, and a qd conversion unit 69 (in FIG. 8, only the output terminals represented by circles in the figure). (Shown), inverse qd conversion unit 66, gate pulse generation unit 67, arithmetic amplifier circuits 63d, 63q, adders 62d, 62q, 65d, 65q and multiplier 64d.
  • the effective current command generation unit 61d generates an effective current command value Idp based on the interconnection point voltage V, the frequency of the power system 50 calculated from the interconnection point voltage V, the capacitor voltage of the capacitor 14 of the converter 11, and the like. ..
  • the reactive current command generation unit 61q generates a reactive current command value Iqp based on the interconnection point voltage V, the frequency of the power system 50, the capacitor voltage of the capacitor 14 of the converter 11, and the like.
  • the phase detection unit 68 uses a known calculation method such as PLL (Phase Locked Loop) or DFT (Discrete Fourier transform) from the interconnection point voltage V to determine the phase of the interconnection point voltage V. To detect.
  • the qd conversion unit 69 converts the three-phase alternating current into a two-phase direct current component of an active component and an ineffective component by dq conversion, using the phase detected by the phase detection unit 68 as a reference phase.
  • the inverse qd conversion unit 66 reverse dq-converts the effective component voltage command value and the invalid component voltage command value, and further performs two-phase / three-phase conversion to generate a three-phase output voltage command value (VRp, VSp, VTp). ..
  • the gate pulse generation unit 67 generates a gate pulse signal for controlling on / off of each switch of the converter 11 by a known PWM control based on the voltage command value.
  • the control device 60 controls the converter 11 with active power and reactive power as command values.
  • the interconnection point voltage V detected by the interconnection point voltage detection device 20 is input to the active current command generation unit 61d, the reactive current command generation unit 61q, and the phase detection unit 68.
  • the phase detection unit 68 detects the phase of the interconnection point voltage V from the interconnection point voltage V by PLL, and outputs the detected phase to the qd conversion unit 69 and the inverse qd conversion unit 66 with the detected phase as the reference phase.
  • the qd conversion unit 69 converts the interconnection point voltage V of each phase and the current of each phase detected by a current detector (not shown) into two phases, and makes the active voltage detection value Edf, the active current detection value Idf, and invalid.
  • the voltage detection value Eqf and the reactive current detection value Iqf are calculated.
  • the control device 60 Since the control device 60 performs non-interference control of calculation of the active power component voltage command value and calculation of the reactive power component voltage command value, the operation of these calculations will be described in order. First, the calculation operation of the active power component voltage command value will be described.
  • the effective current command generation unit 61d inputs the capacitor voltage of the capacitor 14 from the capacitor voltage detector 43, further calculates the frequency of the power system 50 from the interconnection point voltage V, and inputs them to these. Based on this, an effective current command value Idp for outputting a predetermined active power is generated and output to the adder 62d.
  • the adder 62d calculates the deviation between the effective current command value Idp and the effective current detection value Idf obtained by the two-phase conversion in the qd conversion unit 69, and outputs the calculated deviation to the arithmetic amplifier circuit 63d.
  • the arithmetic amplifier circuit 63d arithmetically amplifies this deviation.
  • the effective current is feedback-controlled by the calculation by the adder 62d and the arithmetic amplifier circuit 63d.
  • the arithmetic amplifier circuit 63d outputs the amplified difference to the adder 65d.
  • the effective current detection value Idf is input to the multiplier 64d whose gain is the impedance Xt of the interconnection impedance (reactor in this embodiment), multiplied by the gain Xt, and output to the adder 65q.
  • the adder 65d combines the input difference amplified by the arithmetic amplifier circuit 63d, the active voltage detection value Edf obtained by the two-phase conversion in the qd conversion unit 69, and the reactive current detection value Iqf obtained by multiplying by Xt. Add up to generate the active power component voltage command value.
  • the control device 60 performs non-interference control with the calculation of the reactive power component voltage command value by adding a signal obtained by multiplying the reactive current detection value Iqf by the impedance Xt.
  • the adder 65d outputs the generated active power component voltage command value to the inverse qd conversion unit 66.
  • the capacitor voltage of the capacitor 14 is input in addition to the interconnection point voltage V, and the frequency of the power system 50 is calculated from the interconnection point voltage V, and a predetermined reactive current is determined based on these.
  • a reactive current command value Iqp for outputting power is generated and output to the adder 62q.
  • the adder 62q calculates the deviation between the reactive current command value Iqp and the reactive current detection value Iqf obtained by the two-phase conversion in the qd conversion unit 69, and outputs the calculated deviation to the arithmetic amplifier circuit 63q.
  • the arithmetic amplifier circuit 63q arithmetically amplifies this deviation.
  • the reactive current is feedback-controlled by the calculation by the adder 62q and the arithmetic amplifier circuit 63q.
  • the arithmetic amplifier circuit 63q outputs the amplified difference to the adder 65q.
  • the reactive current detection value Iqf is input to the multiplier 64d whose gain is the impedance Xt of the interconnection impedance (reactor in this embodiment), multiplied by the gain Xt, and output to the adder 65d.
  • the adder 65q combines the input difference amplified by the arithmetic amplifier circuit 63q, the reactive voltage detection value Eqf obtained by the two-phase conversion in the qd conversion unit 69, and the active current detection value Idf obtained by multiplying by Xt. Add up to generate the reactive power component voltage command value.
  • the control device 60 performs non-interference control with the calculation of the active power component voltage command value by adding a signal obtained by multiplying the effective current detection value Idf by the impedance Xt.
  • the adder 65d outputs the generated reactive power component voltage command value to the inverse qd conversion unit 66.
  • the inverse qd conversion unit 66 reverse dq converts the input active power component voltage command value and reactive power component voltage command value, and further performs two-phase / three-phase conversion to obtain a voltage command value VRp for each phase of the converter 11.
  • VSSp, VTp are generated and output to the gate pulse generation unit 67.
  • the gate pulse generation unit 67 generates a carrier wave (for example, a triangular wave) for PWM control, and modulates the input voltage command values VRp, VSp, and VTp of each phase with the carrier wave.
  • the gate pulse generation unit 67 turns on the high side switch 12H and the low side switch 12L of the R phase conversion unit 11R, the S phase conversion unit 11S, and the T phase conversion unit 11T of the converter 11 by modulating the voltage command value with the carrier wave. Generates a gate pulse signal to control off.
  • the gate pulse generation unit 67 outputs the generated gate pulse signal to each switch. In this way, the control device 60 controls the on / off of the high-side switch 12H and the low-side switch 12L of the R-phase conversion unit 11R, the S-phase conversion unit 11S, and the T-phase conversion unit 11T of the converter 11.
  • the power conversion device 10a of the fourth embodiment has the same configuration as the power conversion device 10 of the first embodiment, it has the same effect as the power conversion device of the first embodiment. Further, the power conversion device 10a of the fourth embodiment is configured to be a vector control means for calculating a voltage command value by vector control based on the system voltage (interconnection point voltage V). Therefore, even when the power conversion device 10a uses vector control, by providing an interconnection point voltage detection device having a filtering means by moving average, ripples are attenuated, the detection delay is small, and the interconnection point voltage is small. Can be detected and fed forward, and has the same effect as the power conversion device of the first embodiment. There is a merit that it is sufficient to replace the interconnection point detection unit while keeping the vector control device that has been widely used so far. That is, it is easy to modify the ready-made product.
  • the power conversion device of the fifth embodiment has the same configuration as that of FIG. 1 with the same number. Will be explained.
  • the power conversion device 10b of the fifth embodiment is used in the power generation system 100b as in the first embodiment.
  • the power conversion device 10b is different from the power conversion device 10 of the first embodiment in that it includes a voltage compensation unit 70 that compensates for the detected interconnection point voltage V.
  • the voltage compensation unit 70 compensates for the difference between the rated voltage of the power system 50 and the interconnection point voltage V as the system voltage detected by the interconnection point voltage detection device 20 as the system voltage detection device.
  • the other configuration is the power conversion device 10 of the first embodiment. Since they are the same, the description thereof will be omitted.
  • the voltage compensation unit 70 includes a peak value calculation unit 71, a subtractor 72, and an adder 73.
  • the peak value calculation unit 71 utilizes the fact that the peak value Vpeak of the interconnection point voltage can be calculated by the following equation (6). Therefore, the peak value calculation unit 71 includes a square calculation unit 75, a temporary data holding unit 76, an adder 77, and a route calculation unit 78.
  • Vpeak ((Vp 2 + (Vp 2 ) b)) 0.5 ... (6)
  • Vp is the detected value of the interconnection point voltage V
  • (Vp 2 ) b is the past value of the squared value Vp 2 of the detection value before the period of 1/4 cycle of the interconnection point voltage V.
  • the square calculation unit 75 has a configuration in which the signal lines from the interconnection point voltage detection device 20 (see FIG. 10) are branched into two and the two signal lines are connected to the multiplier 75a.
  • the square value of the interconnection point voltage V is calculated from 75a.
  • the configuration of the square calculation unit 75 is not particularly limited as long as the square value of the interconnection point voltage V can be calculated.
  • the temporary data holding unit 76 includes, for example, a known memory such as a DRAM, SRAM, flash memory, or hard disk drive, stores the squared value Vp 2 of the detected value in the memory, and 1 / of the interconnection point voltage V. After holding for a period of 4 cycles, the square value stored in the memory is output.
  • the detected value Vp of the interconnection point voltage V is input to the peak value calculation unit 71 and the adder 73.
  • the peak value calculation unit 71 calculates the square value Vp 2 of the detection value Vp by the square calculation unit 75, and sets the square value into the temporary data holding unit 76 and the adder 77. Output.
  • the temporary data holding unit 76 When the temporary data holding unit 76 receives the squared value Vp 2 of the detected value Vp, it stores the squared value Vp 2 of the detected value in the memory, holds it for a period of 1/4 cycle of the interconnection point voltage V, and then then the squared value Vp 2 stored in the memory is output as the past value (Vp 2 ) b. In other words, the temporary data holding unit 76, from the square value Vp 2 of the detection value Vp, and outputs the 1/4 was calculated prior cycle square value Vp 2 as the past value (Vp 2) b.
  • the temporary data holding unit 76 sequentially stores the squared value Vp 2 of the detected value in the memory, holds it for a period of 1/4 cycle of the interconnection point voltage V, and then stores the past value (Vp 2 ) b in the adder 77. Output sequentially.
  • the adder 77 adds the squared value Vp 2 of the detected value and the past value (Vp 2 ) b 1/4 cycle before the squared value Vp 2 , and adds the addition result (Vp 2 + (Vp 2 ) b. ) Is output to the route calculation unit 78.
  • the route calculation unit 78 outputs the calculated peak value Vpeak to the subtractor 72. In this way, the peak value calculation unit 71 performs the calculation of the equation (6) to calculate the peak value Vpeak of the interconnection point voltage V.
  • the peak value Vpeak of the interconnection point voltage V is a DC amount.
  • the subtractor 72 is input with the rated voltage of the power system 50 and the peak value Vpeak, and calculates the difference between the rated voltage and the peak value Vpeak as the compensation voltage.
  • the subtractor 72 outputs the compensation voltage to the adder 73.
  • the adder 73 receives the compensation voltage and the interconnection point voltage V, adds the compensation voltage to the interconnection point voltage V, and outputs the compensated interconnection point voltage V to the control device 30.
  • the voltage compensation unit 70 calculates the difference between the rated voltage and the peak value Vpeak of the interconnection point voltage V as the compensation voltage, and adds the calculated compensation voltage to the interconnection point voltage V to connect the interconnection point. Compensate for the deviation between the voltage V and the rated voltage.
  • the power conversion device 10b of the fifth embodiment has the same configuration as the power conversion device 10 of the first embodiment, it has the same effect as the power conversion device of the first embodiment.
  • the power conversion device 10b of the fifth embodiment includes a voltage compensation unit 70 that compensates for the difference between the system voltage (interconnection point voltage V) and the rated voltage of the power system 50, and the voltage compensation unit 70 is the interconnection point.
  • the peak value Vpeak of the voltage V was calculated, and the difference between the rated voltage and the peak value Vpeak was added to the interconnection point voltage V to compensate for the interconnection point voltage V.
  • the difference voltage between the interconnection point voltage V and the voltage component output by feedforward of the interconnection point voltage V can be reduced, and the interconnection point voltage V can be reduced. Can be followed by fluctuations in. Further, when the active power component voltage command value and the reactive power component voltage command value are zero, it is possible to suppress the output of current from the power conversion device 10b.
  • Modification example 1 In the power conversion device 10 of the first embodiment, the case where the effective voltage component voltage command value whose phase is advanced by 1/4 cycle from the interconnection point voltage V is calculated by time-differentiating the detected interconnection point voltage V. As described above, the present invention is not limited to this. In this case, for example, the detected interconnection point voltage V is held in a memory or the like for a period of 1/4 cycle to generate a voltage 1/4 cycle behind the interconnection point voltage V, which is delayed by 1/4 cycle. By multiplying the voltage by -1, a voltage that is 1/4 cycle ahead of the interconnection point voltage V is generated. Then, the effective voltage component voltage command value whose phase is advanced by 1/4 cycle from the interconnection point voltage V is calculated based on the voltage which is advanced by 1/4 cycle from the interconnection point voltage V.
  • Verification experiment 1 As the verification experiment 1, the power conversion device 10 shown in FIG. 1 was simulated, the output of the interconnection point voltage detection device 20 was calculated, and the ripple state of the detected interconnection point voltage V was confirmed. Further, the gain q of the ineffective power component voltage command value generation unit 31 and the gain d of the active power component current command value generation unit 33 are set to zero, and the power conversion device 10 sets a voltage substantially equal to the interconnection point voltage V. The current output from the power converter 10 was calculated and the state of the detection delay of the interconnection point voltage V was confirmed when the power was output, that is, only the feed forward of the interconnection point voltage V was performed.
  • the reason why the detection delay state of the interconnection point voltage V can be investigated by using only the feedforward of the interconnection point voltage V as the power conversion device 10 and calculating the output current of the power conversion device 10 will be described.
  • the power conversion device 10 When there is no detection delay in the interconnection point voltage V, the power conversion device 10 outputs a voltage substantially equal to the interconnection point voltage V, and the difference voltage between the output voltage of the power conversion device 10 and the system voltage of the power system 50. Is almost zero, and the output current of the power converter 10 is also almost zero.
  • the horizontal axis is the time (s) and the vertical axis is the voltage value (PU), and shows the calculation result of the detection value of the interconnection point voltage V detected by the interconnection point voltage detection device 20.
  • the solid line 711 in FIG. 11A shows the detected value of the interconnection point voltage V of the R phase
  • the broken line 712 shows the detection value of the interconnection point voltage V of the S phase
  • the dotted line 713 shows the detection value of the interconnection point voltage V of the T phase. Indicates the detected value. Looking at FIG.
  • FIG. 11B shows the calculation result of the output current of the power conversion device 10 when the horizontal axis is the time (s) and the vertical axis is the current value (PU) and only feedforward of the interconnection point voltage V is used. ing.
  • the solid line 711 in FIG. 11B shows the calculated value of the R-phase current
  • the broken line 712 shows the calculated value of the S-phase current
  • the dotted line 713 shows the calculated value of the T-phase current.
  • Verification experiment 2 In the verification experiment 2, as an example, the power conversion device of the modified example 4 of the second embodiment having the control device 4000 shown in FIG. 5 is simulated, and the interconnection point voltage V is caused to cause a phase jump in the simulation to perform power conversion. The changes in the output voltage, output current, active power and ineffective current of the device were investigated, and the robustness of the power converter was investigated. At the same time, as a comparative example, a power converter that controls the output only by conventional vector control is simulated, and the output voltage, output current, active power, and reactive power of the power converter with respect to the phase jump of the interconnection point voltage are as in the embodiment. The change in reactive power was investigated and the robustness was evaluated. The result is shown in FIG.
  • FIG. 12 shows the time change of the system voltage
  • the solid line 1201 is the u-phase voltage
  • the broken line 1202 is the v-phase
  • the dotted line 1203 is the w-phase voltage.
  • (B) in FIG. 12 shows the time change of the phase angle.
  • (C) in FIG. 12 shows the control result of the embodiment, that is, the time change of the output current of the power conversion device of the embodiment
  • the solid line 1211 is the output current to the u phase
  • the broken line 1212 is the output current to the v phase.
  • Dotted line 1213 indicates the output current to the w phase.
  • D in FIG.
  • FIG. 12 shows the time change of the output current of the power converter of the comparative example
  • the solid line 1204 is the output current to the u phase
  • the broken line 1205 is the output current to the v phase
  • the dotted line 1206 is to the w phase.
  • (E) in FIG. 12 shows the time change of the output of the active power of the power conversion device of the example and the power conversion device of the comparative example
  • the dotted line shows the example and the solid line shows the comparative example.
  • (f) shows the time change of the output of the ineffective power of the power conversion device of the example and the power conversion device of the comparative example
  • the dotted line shows the example and the solid line shows the comparative example.
  • the amount of change in the output of the active power and the reactive power changed by the phase jump is smaller in the example than in the comparative example, and the output returns to the control target amount earlier. You can see that.
  • the power conversion device of the modified example 4 of the second embodiment has high robustness as compared with the conventional vector control.
  • the voltage detector serving as the voltage detection device is used to perform a moving average of the output voltage of the detecting means for a period of one cycle of a fixed cycle, or to calculate an approximate value of the moving average.
  • the filtering means 21 is provided in a voltage detector serving as a voltage detection device, the output voltage of the detection means is moved averaged for several cycles of a fixed cycle (that is, more than one cycle of a fixed cycle), or an approximation of the moving average.
  • a filtering means for calculating the value may be provided.
  • the interconnection point voltage detection device 20 calculates a moving average of the detected voltage for one cycle of the carrier wave used for pulse width modulation control, and calculates this.
  • the interconnection point voltage detection device 20 calculates a moving average of the detected voltage for several cycles of the carrier wave (that is, more than one cycle of the carrier wave) used for pulse width modulation control. , This may be detected as a system voltage.
  • the switch switches at a predetermined switching cycle, and as a converter that outputs power to the power system via the interconnection impedance, pulses having different widths are output at substantially a fixed cycle.
  • the converter 11 in which the switch switches and outputs a predetermined AC voltage has been described, various cycles may be applied as the switching cycle (cycle of the carrier used for pulse width modulation control) of the converter.
  • the switching cycle of the converter is more preferably 13 kHz or more, which exceeds the audible range.
  • the converter 11 that switches the switch at a predetermined switching cycle and outputs power to the power system 50 via the interconnection impedance (reactors 17R, 17S, 17T), and this power.
  • a voltage detector interconnection point voltage detection device 20 that detects the voltage at the interconnection point (terminal LPR, LPS, LPT) of the conversion device 10 and the power system 50, and the above-mentioned mobile averaging for a predetermined period corresponding to the switching cycle.
  • the power converters 10 and 10a include control devices 30, 4000 and 60 that control the converter 11 based on the output voltage of the voltage detector. With such a configuration, it is possible to realize a power conversion device and a power generation system capable of suppressing the ripple of the detected voltage and the detection delay.
  • a value obtained by multiplying the output voltage of the voltage detector by moving average for a predetermined period corresponding to the switching cycle as an effective current command value is set as the effective current command value.
  • the converter 11 may be controlled by the voltage command value calculated based on the above.
  • the instantaneous equations of the above equations (2) and (3) and the instantaneous equations of the above equations (2) and (3) are used based on the output voltage of the voltage detector that has been moved and averaged for a predetermined period corresponding to the switching cycle.
  • the instantaneous voltage (effective component voltage estimated value Vi_d, invalid component voltage estimated value Vi_q) is calculated from the instantaneous equations of the above equations (4) and (5), and the voltage command value of the converter 11 is generated from the instantaneous voltage. It may be.
  • the above configurations are combined, and for example, a value that is a real multiple of the output voltage of the voltage detector that has been moved and averaged for a predetermined period corresponding to the switching cycle is set as the current command value.
  • the instantaneous voltage (effective component voltage estimated value Vi_d, invalid component voltage estimation) is obtained from the instantaneous equations of the above equations (2) and (3) and the instantaneous equations of the above equations (4) and (5).
  • the value Vi_q) may be calculated and the voltage command value of the converter 11 may be generated from the instantaneous voltage.
  • any other location in the power system that is not the interconnection point may be used as long as the impedance from the converter can be estimated.
  • the voltage at another location for example, the interconnection impedance may be measured and obtained by calculation or the like.

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