JP6160193B2 - Control device, power conditioner, distributed power supply system, program, and control method - Google Patents

Description

  The present invention relates to a control device, a power conditioner, a distributed power supply system, a program, and a control method.

  Patent Document 1 discloses an isolated operation detection device that changes the reactive power supplied to the system power supply side according to the frequency deviation of the system power supply and detects the isolated operation of the power conditioner based on the frequency fluctuation of the reactive power. ing. Patent Document 2 discloses a distributed power supply interconnection system that suppresses an increase in voltage at an interconnection point with a distribution system by increasing reactive power.

Patent Document 1 Japanese Unexamined Patent Application Publication No. 2008-54366 Patent Document 2 Japanese Unexamined Patent Application Publication No. 2010-166759

  In some cases, the reactive power is further increased to change the reactive power in accordance with the frequency deviation of the system power supply after increasing the reactive power to suppress the voltage rise. In such a case, the apparent power is increased, and there is a possibility that the burden on the circuit provided in the power conditioner is increased.

  The control device according to one aspect of the present invention is connected to the system power supply according to a frequency deviation indicating a difference between the latest moving average value of the system cycle of the system power supply and a past moving average value from the latest moving average value. A first reactive power change amount deriving unit for deriving a change amount of the first reactive power which is a fast phase reactive power or a slow phase reactive power to be output by the power conditioner to be connected, and interconnection of the power conditioner and the system power source A second reactive power change amount deriving unit for deriving a change amount of the second reactive power that is the fast reactive power to be output by the power conditioner in order to suppress an increase in the voltage at the point; and a change amount of the first reactive power And a control unit that controls the output of the power conditioner based on at least one of the amount of change in the second reactive power, and the control unit is configured when the voltage corresponding to the output voltage of the power conditioner is equal to or higher than the upper limit voltage. First When changing the direction of increasing phase lead reactive power power conditioner is output based on the amount of change in reactive power, so as to reduce the active power power conditioner is outputted, and controls the output of the power conditioner.

  In the above control device, when the voltage corresponding to the output voltage of the power conditioner is equal to or higher than the upper limit voltage, the control unit increases the phase reactive power based on the amount of change in the second reactive power. The output of the power conditioner may be controlled so as to decrease the active power so that the apparent power corresponding to the active power is made smaller than before increasing the fast reactive power.

  When the voltage corresponding to the output voltage of the power conditioner is equal to or higher than the upper limit voltage, the control unit increases the phase reactive power based on the amount of change in the second reactive power. Regardless of the magnitude of the voltage, the output of the power conditioner may be controlled to reduce the active power.

  When the voltage corresponding to the output voltage of the power conditioner is equal to or higher than the upper limit voltage, the control unit increases the phase reactive power based on the amount of change in the second reactive power so as to decrease the active power. The output of the signal may be controlled.

  When the voltage corresponding to the output voltage of the power conditioner is equal to or higher than the upper limit voltage, the control unit increases the phase reactive power based on the amount of change in the second reactive power, based on the amount of change in the first reactive power. Prior to controlling the output of the power conditioner, the output of the power conditioner may be controlled to reduce the active power.

  The control unit, when changing the voltage corresponding to the output voltage of the power conditioner to increase the phase reactive power output by the power conditioner based on the amount of change of the second reactive power when the voltage corresponding to the output voltage is equal to or higher than the upper limit voltage, The output of the inverter may be stopped by controlling the output of the inverter.

  The power conditioner which concerns on 1 aspect of this invention is equipped with the inverter which connects the electric power from a distributed power supply with the electric power from a system power supply, and the said control apparatus, A control part controls the direct current alternating current conversion operation | movement of an inverter. By doing so, the output of the inverter is controlled.

  The distributed power supply system which concerns on 1 aspect of this invention is equipped with the said power conditioner and the said distributed power supply.

  The program which concerns on 1 aspect of this invention is a program for functioning a computer as said control apparatus.

  The control method according to one aspect of the present invention includes a system power supply connected to a system power supply according to a frequency deviation indicating a difference between the latest moving average value of the system cycle of the system power supply and a past moving average value from the latest moving average value. Deriving the amount of change in the first reactive power that is the fast-phase reactive power or the slow-phase reactive power that should be output by the power conditioner, and suppressing the voltage rise at the connection point between the power conditioner and the system power supply To derive the amount of change of the second reactive power that is the phase reactive power to be output by the power conditioner, and based on at least one of the amount of change of the first reactive power and the amount of change of the second reactive power And controlling the output of the power conditioner, and the controlling step includes power control based on the amount of change in the second reactive power when the voltage corresponding to the output voltage of the power conditioner is equal to or higher than the upper limit voltage. If conditioners alters the direction of increasing phase lead reactive power to be output so as to reduce the active power power conditioner is outputted, and controls the output of the power conditioner.

  It should be noted that the above summary of the invention does not enumerate all the necessary features of the present invention. In addition, a sub-combination of these feature groups can also be an invention.

1 is a system configuration diagram illustrating an example of an overall configuration of a solar cell system according to an embodiment. It is a figure which shows an example of the relationship between the active power P and the reactive power Q. It is a figure which shows an example of the relationship between the active power P and the reactive power Q. It is a figure which shows an example of the functional block of the control apparatus which concerns on this embodiment. It is a figure which shows an example of the reactive power q1-frequency deviation characteristic. It is a flowchart which shows an example of the procedure in which a control apparatus performs voltage rise suppression.

  Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. In addition, not all the combinations of features described in the embodiments are essential for the solving means of the invention.

  FIG. 1 is a system configuration diagram showing an example of the overall configuration of the solar cell system according to the present embodiment. The solar cell system includes a solar cell array 200 and a power conditioner 10. The solar cell array 200 has a plurality of solar cell modules connected in series or in parallel. The solar cell array 200 is an example of a distributed power source. As the distributed power source, a gas engine, a gas turbine, a micro gas turbine, a fuel cell, a wind power generator, an electric vehicle, a power storage system, or the like may be used.

  The power conditioner 10 boosts the DC voltage output from the solar cell array 200, converts the boosted DC voltage into an AC voltage, and outputs the AC voltage to the system power supply 300 side. The power conditioner 10 includes a capacitor C1, a booster circuit 20, a capacitor C2, an inverter 40, a coil L2, a capacitor C3, a relay 50, a power supply 60, and a control device 100. In addition, the control apparatus 100 may be provided outside the power conditioner 10 by modularizing. In this case, the control device 100 communicates with a control unit provided in the power conditioner 10 and outputs a control signal for controlling the output of the power conditioner 10 to the control unit provided in the power conditioner 10. May be.

  One end and the other end of the capacitor C <b> 1 are electrically connected to the positive terminal and the negative terminal of the solar cell array 200 to smooth the DC voltage output from the solar cell array 200. The booster circuit 20 includes a coil L1, a switch Tr, and a diode D1. The booster circuit 20 may be a so-called chopper type switching regulator. The booster circuit 20 boosts the voltage from the solar cell array 200.

  The switch Tr may be, for example, an insulated gate bipolar transistor (IGBT). One end of the coil L1 is connected to one end of the capacitor C1, and the other end of the coil L1 is connected to the collector of the switch Tr. The collector of the switch Tr is connected to the anode of the diode D1, and the emitter of the switch Tr is connected to the other end of the capacitor C1. The coil L1 accumulates energy based on the electric power from the solar cell array 200 while the switch Tr is on, and releases the energy accumulated while the switch Tr is off. As a result, the booster circuit 20 boosts the DC voltage from the solar cell array 200. The diode D1 rectifies the output from the coil L1. The diode D1 prevents the boosted DC voltage from flowing from the output side of the booster circuit 20 to the input side.

  Note that the booster circuit 20 is not limited to the above-described configuration, and may be configured by, for example, an insulating booster circuit having a transformer winding such as a half-bridge booster circuit or a full-bridge booster circuit.

  Capacitor C2 smoothes the DC voltage output from booster circuit 20. The inverter 40 includes a switch. When the switch is turned on / off, the inverter 40 converts the DC voltage output from the booster circuit 20 into an AC voltage and outputs the AC voltage to the system power supply 300 or the load 310. Inverter 40 links the power from solar cell array 200 with the power from system power supply 300. The inverter 40 may be constituted by, for example, a single-phase full-bridge PWM inverter that includes four semiconductor switches that are bridge-connected. Of the four semiconductor switches, one pair of semiconductor switches is connected in series. Of the four semiconductor switches, the other pair of semiconductor switches are connected in series and connected in parallel with the one pair of semiconductor switches.

  A coil L2 and a capacitor C3 are provided between the inverter 40 and the system power supply 300. The coil L2 and the capacitor C3 remove noise from the AC voltage output from the inverter 40. A relay 50 is provided between the capacitor C3 and the system power supply 300. Relay 50 switches whether to electrically disconnect between inverter 40 and system power supply 300 or load 310. When the relay 50 is turned on, the power conditioner 10 and the system power supply 300 or the load 310 are electrically connected. When the relay 50 is turned off, the power conditioner 10 and the system power supply 300 or the load 310 are electrically disconnected. .

  The power supply 60 is constituted by, for example, a power supply IC chip. The supply power source 60 is connected to the output side of the booster circuit 20, generates electric power indicating a predetermined voltage supplied to the control device 100 from a DC voltage extracted from the booster circuit 20, and uses the generated electric power to the control device. 100. The power supply 60 is activated when the output voltage from the booster circuit 20 reaches the reference voltage when the switch Tr of the booster circuit 20 is in the OFF state. After the start-up, the supply power supply 60 generates drive power for driving the control device 100 using the power output from the booster circuit 20 and supplies the drive power to the control device 100. The power supply 60 may generate power to be supplied to the control device 100 by directly using power from the system power supply 300.

  The power conditioner 10 further includes voltage sensors 12, 16 and 22, and current sensors 14 and 18. The voltage sensor 12 detects a voltage V1 corresponding to a potential difference between both ends of the solar cell array 200. The voltage sensor 16 detects a voltage V2 corresponding to a potential difference between both ends on the output side of the booster circuit 20. The voltage sensor 22 detects a voltage V3 corresponding to a potential difference between both output terminals of the power conditioner 10. The current sensor 14 detects a current I1 output from the solar cell array 200 and flowing to the input side of the booster circuit 20. The current sensor 18 detects the current I2 output from the booster circuit 20.

  Based on the voltage detected by the voltage sensors 12, 16 and 22 and the current detected by the current sensors 14 and 18 so that the maximum power can be obtained from the solar cell array 200, the control device 100 includes the booster circuit 20, The switching operation of the inverter 40 is controlled to boost the DC voltage output from the solar cell array 200, and the boosted DC voltage is converted into an AC voltage and output to the system power supply 300 side.

  In the power conditioner 10 configured as described above, when the system power supply 300 is stopped, the relay 50 must be turned off to electrically disconnect the power conditioner 10 and the system power supply 300. Further, the power conditioner 10 must control the voltage output from the power conditioner 10 so that the voltage at the connection point between the power conditioner 10 and the system power supply 300 does not exceed the upper limit voltage.

  The control device 100 adjusts the phase difference between the phase of the current output from the inverter 40 and the phase of the voltage, and the amplitude of the current output from the inverter 40, thereby invalidating the phase advance to the system power supply 300 side. The desired reactive power, which is power or lagging reactive power, is supplied. The control device 100 detects the frequency fluctuation of the output voltage of the power conditioner 10 corresponding to the voltage at the connection point, so that the system power supply 300 is stopped, that is, the power conditioner 10 is operating independently. Is detected.

  In addition, when the voltage output from the power conditioner 10 is equal to or higher than the upper limit voltage, the control device 100 determines the phase difference between the phase of the current output from the inverter 40 and the phase of the voltage, and the inverter 40. The phase advance reactive power supplied to the system power supply 300 side is increased by adjusting the amplitude of the current output from. By increasing the phase advance reactive power, the current flowing from the system power supply 300 side becomes a delayed current, and the voltage at the connection point between the power conditioner 10 and the system power supply 300 decreases due to the action of the distribution line impedance. Accordingly, the control device 100 can control the voltage output from the power conditioner 10 to be smaller than the upper limit voltage.

  Here, after increasing the phase reactive power for the purpose of suppressing the voltage rise, the control device 100 may further increase the phase reactive power in order to change the reactive power in accordance with the frequency deviation. . For example, as illustrated in FIG. 2, the control device 100 attempts to increase the reactive power Q to the reactive power Q ′ according to the frequency deviation while maintaining the active power P. In this case, the control device 100 increases the apparent power W to the apparent power W ′. When the apparent power W increases, the current output from the inverter 40 becomes excessive, which may adversely affect elements such as the coil L2 or the capacitor C3 included in the power conditioner 10.

  Therefore, when the phase advance reactive power is increased to suppress the voltage rise, the control device 100 causes the phase of the current output from the inverter 40 to decrease the active power in response to the increase in the phase advance reactive power. And the phase difference between the phase of the voltage and the amplitude of the current output from the inverter 40 are adjusted. The control device 100 may decrease the active power simultaneously with the increase of the phase advance reactive power for suppressing the voltage rise. The control device 100 may decrease the active power immediately after the increase of the phase advance reactive power for suppressing the voltage rise.

  For example, as shown in FIG. 3, the control device 100 tries to increase the reactive power for suppressing the voltage rise to the reactive power Q ′ in the state of the active power P and the reactive power Q. In this case, the control device 100 may reduce the active power to the active power P ′ in parallel with the increase of the reactive power. Accordingly, when the control device 100 tries to increase the reactive power to the reactive power Q ″ while maintaining the active power P ′ so as to change the reactive power according to the frequency deviation, the active power P is maintained. As compared with the case where the reactive power is increased in the state, the increase in the apparent power can be suppressed, whereby the current output from the inverter 40 becomes excessive, so that the coil L2 or the capacitor included in the power conditioner 10 is provided. An adverse effect on elements such as C3 can be suppressed.

  FIG. 4 shows an example of functional blocks of the control device 100 according to the present embodiment. The control device 100 includes a frequency measurement unit 102, a moving average value derivation unit 104, a frequency deviation derivation unit 106, a first reactive power change amount derivation unit, a first reactive power change amount derivation unit 108, an isolated operation detection unit 110, and a second invalidity. A power change amount deriving unit 112, an output voltage obtaining unit 114, a target reactive power deriving unit 116, a relay control unit 120, and a PWM control unit 130 are provided.

  The frequency measurement unit 102 acquires the voltage of the system power supply 300 via the voltage sensor 22 and measures the system frequency indicating the frequency of the system power supply 300 from the acquired voltage. The frequency measuring unit 102 measures, for example, a time difference between a fall and rise intermediate value of the voltage signal detected from the voltage sensor 22 and a next fall and rise intermediate value as one cycle. When the system period of the system power supply 300 is 50 Hz (one system period is 20 milliseconds), the measurement period of the system period may be 1/3 or less of the system period, for example, 5 milliseconds.

  The moving average value deriving unit 104 sequentially derives the moving average value of the system cycle for a predetermined moving average time based on the system cycle measured by the frequency measuring unit 102. The moving average time may be longer than one cycle of the system cycle, for example, 20 msec, and may be equal to or less than the time allowed until the isolated operation state is detected after entering the isolated operation state. The moving average time may be, for example, shorter than 100 milliseconds, and the moving average time may be, for example, 40 milliseconds.

  The frequency deviation deriving unit 106 includes the latest moving average value derived by the moving average value deriving unit 104 and a past moving average value from the latest moving average value, for example, the moving average value deriving unit 104 includes the latest moving average value. The difference from the past moving average value derived by the moving average value deriving unit 104 before a predetermined time (for example, 200 ms) from the end point of the latest system cycle used to derive the frequency is derived as a frequency deviation. . The frequency deviation deriving unit 106 may derive the frequency deviation every cycle that is the same as the measurement cycle of the system cycle, for example, every 5 milliseconds.

  The first reactive power change amount deriving unit 108 derives the current reactive power q1 based on the frequency deviation of the system power supply 300, and the amount of change in the reactive power q1 indicating the difference between the previous reactive power q1 and the current reactive power q1. Δq1 is derived. The first reactive power variation derivation unit 108 may derive the reactive power q1 variation Δq1 so that the reactive power q1 increases in proportion to the frequency deviation of the system power supply 300. The first reactive power change amount deriving unit 108 derives the change amount Δq1 by deriving the reactive power q1 corresponding to the frequency deviation with reference to, for example, the reactive power q1−frequency deviation characteristic as illustrated in FIG. May be. The first reactive power change amount derivation unit 108 is phase reactive power that causes the power conditioner 10 to output a current whose phase is advanced with respect to the system frequency when the frequency deviation of the system power supply 300 is positive. The reactive power q1 is derived. On the other hand, when the frequency deviation of the system power supply 300 is negative, the first reactive power change amount deriving unit 108 is the slow reactive power that causes the power conditioner 10 to output a current whose phase is delayed with respect to the system frequency. A certain reactive power q1 is derived.

  The isolated operation detection unit 110 detects the isolated operation of the power conditioner 10 connected to the system power supply 300 based on the frequency fluctuation of the output voltage of the power conditioner 10 corresponding to the voltage at the connection point. The isolated operation detection unit 110 does not detect voltage frequency fluctuations based on reactive power fluctuations when the system power supply 300 is operating normally. On the other hand, when an abnormality has occurred such as when the system power supply 300 is stopped, the isolated operation detection unit 110 detects the frequency variation of the voltage based on the variation of the reactive power, so that the power conditioner 10 Detects isolated operation.

  The relay control unit 120 turns off the relay 50 and electrically connects between the power conditioner 10 and the system power supply 300 or the load 310 when the single operation detection unit 110 detects the single operation of the power conditioner 10. Cut off.

  The output voltage acquisition unit 114 detects the voltage V <b> 3 that is the output voltage of the power conditioner 10 corresponding to the voltage at the connection point detected by the voltage sensor 22. The second reactive power change amount deriving unit 112 determines whether or not the detected voltage V3 is equal to or higher than a predetermined upper limit voltage Vth. When the detected voltage V3 is equal to or higher than the upper limit voltage Vth, the second reactive power change amount deriving unit 112 increases the reactive power to be supplied to the system power supply 300 side to increase the output voltage of the power conditioner 10. In order to suppress it, the present reactive power q2 is derived, and a change amount Δq2 of the reactive power q2 indicating the difference between the previous reactive power q2 and the current reactive power q2 is derived.

  The target reactive power deriving unit 116 is derived by the previous target reactive power Qc, the variation Δq1 of the reactive power q1 derived by the first reactive power variation deriving unit 108, and the second reactive power variation deriving unit 112. The current target reactive power Qt is derived by adding the amount of change Δq2 of the reactive power q2. The target reactive power deriving unit 116 provides the derived target reactive power Qt to the PWM control unit 130.

  The PWM control unit 130 performs PWM control on the inverter 40 so that the maximum or maximum active power can be obtained from the solar cell array 200. The PWM control unit 130 functions as a control unit that controls the output of the power conditioner based on at least one of the change amount Δq1 of the reactive power q1 and the change amount Δd2 of the reactive power q2. The PWM control unit 130 is output from the inverter 40 based on the target reactive power Qt derived by the target reactive power deriving unit 116 using at least one of the variation Δq1 of the reactive power q1 and the variation Δd2 of the reactive power q2. The reactive power supplied to the system power supply 300 side is controlled by adjusting the phase difference between the current phase and the voltage phase and the amplitude of the current output from the inverter 40.

  The PWM control unit 130 increases the phase reactive power output from the power conditioner 10 based on the change amount Δq2 of the reactive power q2 when the voltage corresponding to the output voltage of the power conditioner is equal to or higher than the upper limit voltage Vth. When changing, you may control the output of the power conditioner 10 so that the active electric power which the power conditioner 10 outputs may be decreased.

  When the voltage corresponding to the output voltage of the power conditioner 10 is equal to or higher than the upper limit voltage Vth, the PWM control unit 130 increases the phase reactive power and the effective reactive power when the phase reactive power is increased based on the change amount Δq2 of the reactive power q2. The output of the power conditioner 10 may be controlled so as to decrease the active power so that the apparent power corresponding to the power is smaller than before increasing the fast reactive power.

  When the voltage corresponding to the output voltage of the power conditioner 10 is equal to or higher than the upper limit voltage Vth, the PWM control unit 130 increases the phase reactive power when the phase reactive power is increased based on the change amount Δq2 of the reactive power q2. Regardless of the magnitude of the voltage after the operation, the output of the power conditioner 10 may be controlled to reduce the active power.

  When the voltage corresponding to the output voltage of the power conditioner 10 is equal to or higher than the upper limit voltage Vth, the PWM control unit 130 decreases the active power when increasing the phase advance reactive power based on the amount of change in the reactive power q2. The output of the power conditioner 10 may be controlled.

  When the voltage corresponding to the output voltage of the power conditioner 10 is equal to or higher than the upper limit voltage Vth, the PWM control unit 130 increases the phase reactive power based on the amount of change in the reactive power q2, and the amount of change Δq1 in the reactive power q1. Before controlling the output of the power conditioner 10 based on the above, the output of the power conditioner may be controlled to reduce the active power.

  When the voltage corresponding to the output voltage of the power conditioner 10 is equal to or higher than the upper limit voltage Vth, the PWM control unit 130 increases the reactive power q2 that is the phase advance reactive power so as to suppress an increase in the output voltage of the power conditioner 10. Correspondingly, the active power P supplied to the system power supply 300 may be decreased. The PWM control unit 130 decreases the active power P by a predetermined ratio or amount from the current active power P in response to increasing the reactive power q2 when the voltage V3 is equal to or higher than the upper limit voltage Vth. May be.

  In response to increasing the reactive power q2 when the voltage V3 is equal to or higher than the upper limit voltage Vth, the PWM control unit 130 increases the reactive power Q before the apparent power W corresponding to the reactive power Q and the active power P increases. The active power P may be decreased so as to be smaller than that. The PWM control unit 130 may decrease the active power P when the reactive power Q2 is increased by increasing the reactive power q2 when the voltage V3 is equal to or higher than the upper limit voltage Vth.

  Here, although the PWM control unit 130 increases the reactive power q2 in order to suppress the increase in the output voltage of the power conditioner 10, the increase in the output voltage of the power conditioner 10 is insufficiently suppressed. In some cases, the active power P may be reduced. In such a case, the PWM control unit 130 may increase the reactive power q1 to change the reactive power Q according to the frequency deviation of the system power supply 300 before reducing the active power P. As a result, as the reactive power q1 increases, the apparent power increases, which may adversely affect elements such as the coil L2 or the capacitor C3 included in the power conditioner 10.

  Therefore, the PWM control unit 130 responds to increasing the reactive power q2 when the voltage V3 is equal to or higher than the upper limit voltage Vth, and the active power regardless of the magnitude of the voltage V3 after increasing the reactive power Q. P may be decreased in advance. Further, when the reactive power q2 is increased when the voltage V3 is equal to or higher than the upper limit voltage Vth, the PWM control unit 130 increases the reactive power q1 in accordance with the frequency deviation of the system power supply 300 before changing the reactive power Q. The active power P may be reduced in advance.

  When the voltage V3 is equal to or higher than the upper limit voltage Vth, the PWM control unit 130 changes the phase reactive power output by the power conditioner based on the change amount Δq2 of the reactive power q2. The output of the power conditioner 10 may be stopped by controlling the output of 10. When the voltage V3 is equal to or higher than the upper limit voltage Vth, the PWM control unit 130 reduces the active power P to zero when the phase reactive power output from the power conditioner is increased based on the change amount Δq2 of the reactive power q2. It may be. When the voltage V3 is equal to or higher than the upper limit voltage Vth, when changing the phase reactive power output from the power conditioner based on the amount of change Δq2 of the reactive power q2, the PWM control unit 130 is connected to the relay control unit. The relay control unit 120 outputs an off control signal for turning off the relay 50 to the 120, and the relay control unit 120 turns off the relay 50 in accordance with the off control signal, thereby connecting the power conditioner 10 and the system power supply 300 or the load 310. It may be electrically cut off.

  FIG. 6 is a flowchart illustrating an example of a procedure in which the control device 100 performs voltage rise suppression. The control device 100 periodically executes the procedure. The output voltage acquisition unit 114 acquires the voltage V3 output from the power conditioner 10 via the voltage sensor 22 (S100). The second reactive power change amount deriving unit 112 determines whether or not the voltage V3 is equal to or higher than the upper limit voltage Vth (S102). When the voltage V3 is equal to or higher than the upper limit voltage Vth, the second reactive power change amount deriving unit 112 derives the change amount Δq2 of the reactive power q2 so as to suppress an increase in the output voltage of the power conditioner 10. The PWM control unit 130 receives an instruction from the target reactive power deriving unit 116 to output the target reactive power Qt including the change amount Δq2 of the reactive power q2, and increases the phase reactive power output from the power conditioner 10. The active power output from the power conditioner 10 is decreased (S104). When the voltage V3 is equal to or higher than the upper limit voltage Vth, the PWM control unit 130 increases the phase reactive power output from the power conditioner 10 even when the power factor is equal to or higher than the lower limit threshold, for example, 0.85 or higher. In addition, the active power output from the power conditioner 10 is reduced.

  If voltage V3 is smaller than the upper limit voltage, PWM control unit 130 determines whether active power is currently suppressed (S106). If the active power is suppressed, the PWM control unit 130 increases the active power output from the power conditioner 10 so that the active power is maximized or maximized (S108). On the other hand, if the active power is not suppressed, the PWM control unit 130 determines whether or not the reactive power q2 that is the fast reactive power is zero (S110). If reactive power q2 is not zero, second reactive power change amount deriving unit 112 derives a change amount Δq2 in order to reduce reactive power q2. The PWM control unit 130 reduces the reactive power output from the power conditioner 10 so that the reactive power q2 that is the phase advance reactive power becomes zero (S112).

  As described above, according to the control device 100 of the present embodiment, when the phase advance reactive power is increased in order to suppress the voltage increase, the active power is decreased as the phase advance reactive power is increased. As a result, when the reactive power is changed in accordance with the frequency deviation of the system power supply 300 after the control device 100 increases the phase advance reactive power to suppress the voltage rise, the current output from the inverter 40 is excessive. By becoming, it can suppress having a bad influence on elements, such as the coil L2 or the capacitor | condenser C3 with which the power conditioner 10 is provided.

  In addition, each part with which the control apparatus 100 which concerns on this embodiment is provided installs the program recorded on the computer-readable recording medium which performs various processes regarding control of the active power and reactive power of the power conditioner 10, and this program You may comprise by making a computer perform. That is, the control device 100 can be configured by causing the computer to function as each unit included in the control device 100 by causing the computer to execute programs for performing various processes relating to the control of the active power and reactive power of the power conditioner 10. Good.

  The computer has various memories such as a CPU, ROM, RAM, and EEPROM (registered trademark), a communication bus, and an interface. The CPU reads and sequentially executes a processing program stored in the ROM as firmware in advance, and thereby the control device 100. Function as.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

  The order of execution of each process such as operations, procedures, steps, and stages in the apparatus, system, program, and method shown in the claims, the description, and the drawings is particularly “before” or “prior to”. It should be noted that the output can be realized in any order unless the output of the previous process is used in the subsequent process. Regarding the operation flow in the claims, the description, and the drawings, even if it is described using “first”, “next”, etc. for convenience, it means that it is essential to carry out in this order. It is not a thing.

DESCRIPTION OF SYMBOLS 10 Power conditioner 20 Booster circuit 40 Inverter 50 Relay 60 Power supply 100 Controller 102 Frequency measurement part 104 Moving average value derivation part 106 Frequency deviation derivation part 108 1st reactive power variation derivation part 110 Independent operation detection part 112 2nd invalidity Power change amount deriving unit 114 Output voltage obtaining unit 116 Target reactive power deriving unit 120 Relay control unit 130 PWM control unit 200 Solar cell array 300 System power supply 310 Load

Claims (9)

The power conditioner linked to the system power supply should output according to the frequency deviation indicating the difference between the latest moving average value of the system power supply system cycle and the previous moving average value from the latest moving average value. A first reactive power change amount deriving unit for deriving a change amount of the first reactive power that is a fast phase reactive power or a slow phase reactive power;
Second reactive power for deriving an amount of change in second reactive power that is a fast reactive power to be output by the power conditioner in order to suppress an increase in voltage at a connection point between the power conditioner and the system power supply A variation derivation unit;
A control unit that controls an output of the power conditioner based on at least one of a change amount of the first reactive power and a change amount of the second reactive power;
The control unit increases the phase reactive power output by the power conditioner based on the amount of change in the second reactive power when the voltage corresponding to the output voltage of the power conditioner is equal to or higher than the upper limit voltage. In the case of changing, before controlling the output of the power conditioner based on the amount of change in the first reactive power, the output of the power conditioner is controlled so as to reduce the active power output by the power conditioner. To
Control device.   When the voltage corresponding to the output voltage of the power conditioner is equal to or higher than the upper limit voltage, the control unit increases the phase reactive power based on the amount of change in the second reactive power. The output of the power conditioner is controlled so as to decrease the active power so as to make the apparent power corresponding to the active power smaller than before increasing the fast reactive power. Control device.   When the voltage corresponding to the output voltage of the power conditioner is equal to or higher than the upper limit voltage, the control unit increases the phase reactive power based on the amount of change in the second reactive power. 3. The control device according to claim 1, wherein an output of the power conditioner is controlled so as to decrease the active power regardless of the magnitude of the voltage after increasing the power.   When the voltage corresponding to the output voltage of the power conditioner is equal to or higher than the upper limit voltage, the control unit increases the active reactive power when the phase reactive power is increased based on a change amount of the second reactive power. The control device according to any one of claims 1 to 3, wherein an output of the power conditioner is controlled so as to be reduced. The control unit increases the phase reactive power output by the power conditioner based on the amount of change in the second reactive power when the voltage corresponding to the output voltage of the power conditioner is equal to or higher than the upper limit voltage. The control device according to any one of claims 1 to 4 , wherein, when changing, the output of the power conditioner is controlled to stop the output of the power conditioner. An inverter interconnecting power from a distributed power source with power from the system power source;
A control device according to any one of claims 1 to 5 ,
The said control part is a power conditioner which controls the output of the said power conditioner by controlling the direct current | flow alternating current conversion operation | movement of the said inverter. A power conditioner according to claim 6 ;
A distributed power supply system comprising the distributed power supply. The program for functioning a computer as a control apparatus as described in any one of Claims 1-5 . The power conditioner linked to the system power supply should output according to the frequency deviation indicating the difference between the latest moving average value of the system power supply system cycle and the previous moving average value from the latest moving average value. Deriving the amount of change in the first reactive power that is the fast phase reactive power or the slow phase reactive power;
Deriving an amount of change in second reactive power that is a phase reactive power to be output by the power conditioner in order to suppress an increase in voltage at an interconnection point between the power conditioner and the system power supply;
Controlling the output of the power conditioner based on at least one of a change amount of the first reactive power and a change amount of the second reactive power,
The controlling step increases the phase reactive power output from the power conditioner based on the amount of change in the second reactive power when the voltage corresponding to the output voltage of the power conditioner is equal to or higher than the upper limit voltage. In order to reduce the active power output by the power conditioner before the output of the power conditioner is controlled based on the amount of change in the first reactive power, the output of the power conditioner is Control method to control.

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