JP2009225489A - Operation controller for power conditioner and solar light generating system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To operate a plurality of non-insulated power conditioners, which convert the DC power from a plurality of solar cell arrays into AC power, with high efficiency, without using a mechanical switch. <P>SOLUTION: When the generated output of a solar cell is low, it inputs the DC power from the solar cell array 5 of a second power generating system into the power conditioner 4 of a first power generating system by switching on first and second thyristors 20 and 21, and converts the DC power of the solar cell array 2 of the first power generating system and the DC power from the solar cell array 5 of the second power generating system into AC power by a power conditioner 4, and also stops the operation of a power conditioner 7 by switching off an IGBT 22 thereby breaking the supply of the DC power 7 of the second power generating system. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an apparatus for controlling the operation of a power conditioner connected to a system power source by converting DC power generated by a DC power source such as a solar cell or a fuel cell into AC power, and sunlight using the same. The power generation system.

  In a solar power generation system, a power conditioner having an inverter that converts direct-current power generated by a solar cell into alternating-current power and a protection device for system interconnection is used, and such a power conditioner is generally shown in FIG. As shown in FIG. 3, the conversion efficiency is lowered at the time of low output with respect to the rated output power.

For this reason, multiple inverters are connected in parallel, the number of inverters to be operated is switched according to the output power of the solar cell, and when the output power is low, the number of inverters to be operated is reduced to convert at low output There is one that suppresses the decrease in efficiency (for example, see Patent Document 1).
Japanese Patent No. 3112584

  The above-mentioned Patent Document 1 discloses an embodiment in which an insulation transformer is used to electrically insulate a direct current section and an alternating current section. However, as a power conditioner, a non-insulated power conditioner that does not use an insulation transformer is disclosed. Na is often used because of its high efficiency.

  A plurality of such non-insulated power conditioners, for example, two non-insulated power conditioners 40 and 41, are connected to two solar cell arrays 42 and 43 as shown in FIG. , 50 and connection boxes 44, 45 having switches 51, 52, respectively, DC power from each of the solar cell arrays 42, 43 is converted into AC power and linked to the system power supply 46, and solar cells When the output power of the solar cell is low, only one power conditioner 40 is operated. When the output power of the solar cell is high, it is conceivable to operate the two power conditioners 40 and 41.

  However, the DC power line 47 between one solar cell array 42 and the power conditioner 40 and the positive electrodes 47P and 48P of the DC power line 48 between the other solar cell array 43 and the power conditioner 41 and the negative electrode. If the inverters 47N and 48N are simply connected as shown in FIG. 6, the power conditioners 40 and 41 are non-insulated, so that during operation, as indicated by arrows, the DC power line 47 A closed loop is formed through the positive electrode side 47P, the power conditioners 40 and 41, and the negative electrode side 48N of the DC power line 48, and there is a problem that it does not operate normally.

  In addition, it is conceivable to connect the DC power line using a mechanical switch such as an electromagnetic relay, but this is difficult because it is necessary to open and close the DC current with directionality. There are also problems such as the number of times of life and welding of contacts by arc.

  The present invention has been made in view of the above points, and mechanically opens and closes a plurality of non-insulated power conditioners that convert DC power from a plurality of DC power sources into AC power. The purpose is to enable operation with high efficiency without using a vessel.

  (1) A power conditioner operation control device according to the present invention is connected to a plurality of DC power sources, converts a plurality of DC power generated by the DC power source into AC power, and links to a system power source. A device for controlling the operation of the non-insulated power conditioner of the plurality of sets of power generation systems including the DC power supply and the power conditioner individually connected to the DC power supply, or And the other power generation system is a sub power generation system, and the positive side and the negative side of the DC power line between the DC power source and the power conditioner of the main power generation system. Unidirectional switching elements on the positive electrode side and the negative electrode side of the DC power line between the DC power source and the power conditioner of the sub power generation system, respectively. The switching element is inserted on the power conditioner side of the DC power line of the auxiliary power generation system from the connection point of the unidirectional switching element, and the unidirectionality connects the positive electrode side. A switching element is inserted in the direction in which current flows from the sub power generation system to the main power generation system, while the unidirectional switching element that connects the negative electrode side transmits current from the main power generation system to the sub power generation system. Inserted in the flowing direction, and based on the output power of the power conditioner or the output power of the DC power supply, the number of operating the plurality of power conditioners by controlling on / off of the unidirectional switching element and the switching element Is to control.

The DC power source refers to a power source that generates DC power, such as a solar cell, wind power generation, and a fuel cell.
The non-insulated power conditioner refers to a transformer-less power conditioner that does not have a transformer.

  The power conditioner of the main power generation system is operated even when the operation of the power conditioner of the sub power generation system is stopped because the output power of the DC power supply is low. It is the one with the highest priority among na.

  One set may be sufficient as an auxiliary power generation system, and two or more sets may be sufficient as it.

  A unidirectional switching element refers to a semiconductor element for switching, for example, a thyristor, in which a current flows in one direction.

  A switching element refers to a semiconductor element for switching, such as a transistor, an FET, or an IGBT.

  The control function of the operation control device may be incorporated in a power conditioner, for example, a power conditioner of the main power generation system.

  According to the operation control apparatus of the power conditioner of the present invention, when the output power of the DC power source is low, the unidirectional switching element between the main power generation system and the sub power generation system is turned on to turn off the DC power source of the sub power generation system. DC power is input to the power conditioner of the main power generation system, and the power conditioner converts DC power from the DC power sources of both power generation systems into AC power, and the switching elements of the sub power generation system are turned off to generate the sub power generation. By shutting off the supply of DC power to the system power conditioner, the operation of the power conditioner of the secondary power generation system can be stopped. As a result, when the output power of the DC power supply is low, the number of power conditioners to be operated is reduced, and the decrease in conversion efficiency at the time of low output is suppressed, and the power conditioner can be operated with high conversion efficiency. .

  In addition, the switching element of the secondary power generation system is turned off to cut off the supply of DC power to the power conditioner of the secondary power generation system, and the power conditioner is stopped, so that power is not consumed by the power conditioner. The closed loop as shown in FIG. 6 is not configured. Furthermore, since switching is performed by a semiconductor element rather than a mechanical switch, the life is long and the contacts are not welded.

  (2) In one embodiment of the operation controller of the power conditioner of the present invention, the DC power supply is a solar cell array, and the output power of the power conditioner of the main power generation system is equal to or greater than a threshold value. Turns off the unidirectional switching element that connects the positive electrode side and the negative electrode side, and turns on the switching element to operate the power conditioner of the sub power generation system, and the power conditioner of the main power generation system When the output power of the sub power generation system is less than the threshold value, the unidirectional switching element connecting the positive electrode side and the negative electrode side is turned on, and the switching element is turned off to turn on the power conditioner of the sub power generation system. The operation is stopped.

  The unidirectional switching element is turned off, and the threshold value for turning on the switching element and the unidirectional switching element are turned on, and the threshold value for turning off the switching element is different to provide hysteresis. May be.

  When there are a plurality of sets of sub power generation systems, it is preferable to set a threshold value corresponding to each set and to control on / off of the unidirectional switching element and the switching element for each set.

  According to this embodiment, when the output power of the solar cell is high and the output power of the power conditioner of the main power generation system is greater than or equal to the threshold value, the unidirectional switching element between the main power generation system and the sub power generation system is When turning off and turning on the switching element of the secondary power generation system to operate the power conditioner of the secondary power generation system, while the output power of the solar cell is low and the output power of the power conditioner of the main power generation system is less than the threshold value Since the unidirectional switching element between the main power generation system and the sub power generation system is turned on, and the switching element of the sub power generation system is turned off to stop the power conditioner of the sub power generation system. It is possible to operate the inverter with high conversion efficiency by suppressing the decrease in conversion efficiency.

  (3) In the embodiment of (2), each power conditioner has a smoothing capacitor, the unidirectional switching element is a thyristor, and the output power of the power conditioner of the main power generation system is If it is equal to or higher than the threshold value, the switching element may be turned on when the input voltage of the power conditioner of the sub power generation system is reduced to a predetermined voltage or lower.

  The predetermined voltage is preferably a voltage in a state where a smoothing capacitor of a power conditioner of the sub power generation system is discharged.

  To turn the thyristor between the DC power line of the main power generation system and the DC power line of the sub power generation system from on to off, a reverse bias voltage is applied to the thyristor and the current flowing from the anode to the cathode is kept below the holding current. It is necessary to.

  According to this embodiment, the switching element is turned on when the input voltage of the power conditioner of the secondary power generation system is equal to or lower than the predetermined voltage, that is, when the smoothing capacitor of the power conditioner is discharged. When the element is turned on, a charging current flows from the solar battery array of the secondary power generation system to the smoothing capacitor of the inverter, and the output voltage of the solar battery array of the secondary power generation system is lower than the output voltage of the solar battery array of the main power generation system. Thus, the thyristor is reverse-biased, thereby turning off the thyristor and shutting off the DC power line of the main power generation system and the DC power line of the sub power generation system, and a solar cell array for each power generation system. DC power from the converter is converted into AC power by the power conditioner. It is possible.

  (4) The photovoltaic power generation system of the present invention includes a plurality of solar cell arrays and a plurality of non-insulated power conditioners connected to the solar cell arrays, respectively, and is generated by the solar cell array. A photovoltaic power generation system that converts DC power into AC power by the power conditioner and is linked to a system power supply, the solar battery array and the power conditioner individually connected to the solar battery array, A set of power generation systems as a main power generation system, and another set of power generation systems as sub power generation systems, and a solar cell array of the main power generation system, The positive electrode side and the negative electrode side of the DC power line between the power conditioner and the solar cell array of the sub power generation system and the power conditioner Are connected to the positive electrode side and the negative electrode side of the DC power line via a unidirectional switching element, respectively, and the power condition is higher than the connection point of the unidirectional switching element of the DC power line of the sub power generation system. A switching element is inserted on the negative side, and the unidirectional switching element connecting the positive side is inserted in a direction in which a current flows from the sub power generation system to the main power generation system, while connecting the negative side A unidirectional switching element is inserted in a direction in which current flows from the main power generation system to the sub power generation system, and based on the output power of the power conditioner or the output power of the solar cell array, the unidirectional switching element And controlling the on / off of the switching element to control the plurality of power conditioners. And a controller for controlling the number of operating conditioner.

  According to the solar power generation system of the present invention, when the output power of the solar cell is low, the unidirectional switching element between the main power generation system and the sub power generation system is turned on to direct current power from the solar cell array of the sub power generation system. Is input to the power conditioner of the main power generation system, and the power conditioner converts the DC power from the solar cell arrays of both power generation systems into AC power, and the switching element of the sub power generation system is turned off to turn on the sub power generation system. By shutting off the supply of DC power to the power conditioner, the operation of the power conditioner of the secondary power generation system can be stopped. As a result, when the output power of the solar cell is low, the number of power conditioners to be operated is reduced, the reduction in conversion efficiency at the time of low output is suppressed, and the power conditioner can be operated with high conversion efficiency. .

  Moreover, the switching element is turned off to cut off the supply of DC power to the power conditioner of the secondary power generation system, and the power conditioner is stopped. No closed loop as shown in FIG. Furthermore, since switching is performed by a semiconductor element rather than a mechanical switch, the life is long and the contacts are not welded.

   (5) In one embodiment of the photovoltaic power generation system of the present invention, the control device, when the output power of the power conditioner of the main power generation system is greater than or equal to a threshold, And turning off the unidirectional switching element that connects the power source to operate the power conditioner of the sub power generation system, and the output power of the power conditioner of the main power generation system is less than the threshold value. In some cases, the unidirectional switching element connecting the positive electrode side and the negative electrode side is turned on, and the switching element is turned off to stop the operation of the power conditioner of the auxiliary power generation system. Good.

  According to this embodiment, when the generated power of the solar cell is high and the output power of the power conditioner of the main power generation system is greater than or equal to the threshold value, the unidirectional switching element between the main power generation system and the sub power generation system is When turning off and turning on the switching element of the secondary power generation system to operate the power conditioner of the secondary power generation system, while the output power of the solar cell is low and the output power of the power conditioner of the main power generation system is less than the threshold value Since the unidirectional switching element between the main power generation system and the sub power generation system is turned on, and the switching element of the sub power generation system is turned off to stop the power conditioner of the sub power generation system. It is possible to operate the inverter with high conversion efficiency by suppressing the decrease in conversion efficiency.

   (6) In the embodiment of (5), each power conditioner has a smoothing capacitor, the unidirectional switching element is a thyristor, and the control device is a power conditioner of the main power generation system. When the output power of the sub power generation system is equal to or higher than the threshold value, the switching element may be turned on when the input voltage of the power conditioner of the sub power generation system is reduced to a predetermined voltage or lower.

  According to this embodiment, the switching element is turned on when the input voltage of the power conditioner of the secondary power generation system is equal to or lower than the predetermined voltage, that is, when the smoothing capacitor of the power conditioner is discharged. When the element is turned on, a charging current flows from the solar battery array of the secondary power generation system to the smoothing capacitor of the inverter, and the output voltage of the solar battery array of the secondary power generation system is lower than the output voltage of the solar battery array of the main power generation system. Thus, the thyristor is reverse-biased, thereby turning off the thyristor and shutting off the DC power line of the main power generation system and the DC power line of the sub power generation system, and a solar cell array for each power generation system. Can be converted into AC power.

  According to the present invention, when the output power of a DC power source such as a solar battery is low, DC power from the DC power source of the secondary power generation system is input to the power conditioner of the main power generation system, and the power conditioner of the main power generation system The operation of the power conditioner of the sub power generation system is stopped by converting the DC power from the DC power sources of both power generation systems into AC power and shutting off the supply of DC power to the power conditioner of the sub power generation system. As a result, when the output power of the DC power supply is low, the number of power conditioners to be operated can be reduced, the decrease in conversion efficiency at low output can be suppressed, and the power conditioner can be operated with high conversion efficiency. It becomes possible.

  In addition, since the supply of DC power to the power conditioner of the secondary power generation system is cut off and the power conditioner is stopped, power is not consumed by the power conditioner, and normal operation is hindered. A closed loop is not constructed. Furthermore, since switching is performed by a semiconductor element rather than a mechanical switch, the life is long and the contacts are not welded.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
FIG. 1 is a configuration diagram of a photovoltaic power generation system according to an embodiment of the present invention.

  The solar power generation system 1 of this embodiment includes a first power generation system as a main power generation system including a first solar cell array 2, a first connection box 3, and a first power conditioner 4, and a second power generation system. Of the solar cell array 5, the second junction box 6, and the second power conditioner 7 are connected in parallel to the second photovoltaic power generation system as a secondary power generation system, and the control device 8 Thus, as will be described later, the number of operating inverters is controlled.

  Each of the solar cell arrays 2 and 5 is configured to obtain a required generated power by connecting a plurality of solar cell modules in series and in parallel, and its rated output is, for example, 4 kW.

  Each of the connection boxes 3 and 6 has backflow prevention diodes 9 and 10 and switches 11 and 12, respectively, and collects electric power generated by the solar cell arrays 2 and 5, respectively.

  Each of the power conditioners 4 and 7 interposed between the solar cell arrays 2 and 5 and the system power supply 13 is a non-insulated (transformer-less) power conditioner that does not include an insulating transformer, and its rated output is For example, 4 kW.

  As shown in FIG. 2, the power conditioners 4 and 7 include a smoothing electrolytic capacitor C1, a booster circuit 14 having switch elements S1 and S2, an inductor L1, and a smoothing electrolytic capacitor C2, and switch elements S3 to S3. An inverter circuit 15 having S6 and inductors L2 and L3, a system switch 16 and a power conditioner control unit (not shown) are provided.

  In the power conditioners 4 and 7, the input voltage from the solar cell arrays 2 and 5 smoothed by the smoothing electrolytic capacitor C <b> 1 is boosted by the booster circuit 14 and supplied to the inverter circuit 15. It is converted into AC power and output via the system switch 16.

  In this embodiment, when the generated power of the solar cell is high, the first and second power conditioners 4 and 7 are operated to convert the DC power from the first and second solar cell arrays 2 and 5 into AC power, respectively. On the other hand, when the generated power of the solar cell is low, only the first power conditioner 4 is operated to convert the DC power from the first and second solar cell arrays 2 and 5 into AC power. This suppresses a decrease in conversion efficiency at the time of low output.

  For this reason, as shown in FIG. 1, the positive electrode side 18P and the negative electrode side 18N of the DC power line 18 between the first solar cell array 2 and the first power conditioner 4 of the first power generation system are The first and second thyristors 20 and 21 are connected to the positive side 19P and the negative side 19N of the DC power line 19 between the second solar cell array 5 and the second power conditioner 7 of the second power generation system. Connected to each other.

  The first thyristor 20 has a cathode at the first power generation system so that current flows from the positive electrode side 19P of the DC power line 19 of the second power generation system to the positive electrode side 18P of the DC power line 18 of the first power generation system. The DC power line 18 is connected to the positive electrode side 18P, and the anode is connected to the positive electrode side 19P of the DC power line 19 of the second power generation system. In addition, the second thyristor 21 has a cathode connected to the second power supply system so that a current flows from the negative electrode side 18N of the DC power line 18 of the first power generation system to the negative electrode side 19N of the DC power line 19 of the second power generation system. The anode is connected to the negative side 19N of the DC power line 19 of the first power generation system, and the anode is connected to the negative side 18N of the DC power line 18 of the first power generation system. A first control signal sigA from the control device 8 is given to the gates of the thyristors 20 and 21.

  An IGBT 22 is inserted into the positive electrode side 19P of the DC power line 19 of the second power generation system. The IGBT 22 has an emitter connected to the second power conditioner 7 side and a collector connected to the junction box 6. The second control signal sigB from the control device 8 is given to the gate.

  The control device 8 controls the on / off of the first and second thyristors 20 and 21 and the IGBT 22 based on the output power of the first power conditioner 4 measured by the power meter 17 to operate the power conditioner. Control the number. The control device 8 is provided with a detection value DC1 of the input voltage of the second power conditioner 2 as will be described later.

  FIG. 3 is a time chart for explaining the operation of this embodiment. FIG. 3A shows the output power of the first power conditioner 4, and FIG. 3B shows the first and second thyristors 20, 21. The first control signal sigA for the first power conditioner 4, FIG. 2C shows the second control signal sigB for the IGBT 22, FIG. 4D shows the operating state of the first power conditioner 4, and FIG. The operation states of the conditioner 7 are shown.

  When the generated power of the solar cell is low, such as at the time of start-up in the morning, and the output power of the first power conditioner 4 shown in FIG. 5A is less than a preset first threshold L1, for example, less than 4 kW, For example, as shown in the period T1, the first control signal sigA is turned on and the first and second thyristors 20 and 21 are turned on, while the second control signal sigB is turned off and the IGBT 22 is turned off. ing. As a result, the DC power from the first and second solar cell arrays 2 and 5 is input only to the first power conditioner 4 and is converted into AC power by the first power conditioner 4 to be system power supply. Connect to 13. At this time, DC power is not supplied from the solar cell array 5 to the second power conditioner 7 and is stopped as shown in FIG. 6E, and the closed loop shown in FIG. 6 is configured. In addition, the second power conditioner 7 does not consume power.

  Next, when the output power of the first power conditioner 4 shown in FIG. 5A becomes equal to or higher than the first threshold L1, for example, in addition to the first power conditioner 4 as shown in a period T2. The first control signal sigA is turned off as shown in FIG. 5B so that the second power conditioner 7 is also operated, and the second control signal sigB is changed as shown in FIG. Turn on.

  When the second control signal sigB is turned on, the IGBT 22 is turned on and the DC power from the second solar cell array 5 is supplied to the second power conditioner 7 so that the second power conditioner 7 operates. To start. When the IGBT 22 is turned on, as will be described later, the electrolytic capacitors C1 and C2 for smoothing shown in FIG. 2 of the second power conditioner 7 are charged, and the output voltage of the second solar cell array 5 is reduced. One thyristor 20 is reverse biased and turned off, and the second thyristor 21 is also turned off.

  In order to reversely bias the first thyristor 20 off, it is necessary to charge the electrolytic capacitors C1 and C2 for smoothing as will be described later, so the control device 8 causes the electrolytic capacitors C1 and C2 to discharge. After confirming that the detected value DC1 of the input voltage of the second power conditioner 7 has dropped to a predetermined voltage or less, the IGBT 22 is turned on.

  Next, assuming that the output power of the first power conditioner 4 and the second power conditioner 7 is substantially the same, the output power of the first power conditioner 4 is as shown in FIG. When it becomes less than the preset second threshold L2, for example, less than 1 kW, for example, as shown in the period T3, the operation of the second power conditioner 7 is stopped and only the first power conditioner 4 is operated. To control. That is, as shown in FIG. 5B, the first control signal sigA is turned on to turn on the first and second thyristors 20 and 21, while the second control signal sigB is turned off and the IGBT 22 is turned off. To do. Thus, the DC power from the first and second solar cell arrays 2 and 5 is input only to the first power conditioner 4 while the DC power from the solar cell array 5 to the second power conditioner 7 is input. Shut off the power and stop the operation.

  Thus, the number of operating power conditioners can be automatically controlled according to the output power of the first power conditioner 4 corresponding to the generated power of the solar cell.

  As shown in FIG. 5A, the second threshold L2 is set to a value lower than the first threshold L1 so as to have hysteresis, thereby preventing repeated on / off. I have to.

  Next, the operation of the first and second thyristors 20 and 21 will be described.

  When the thyristor is turned on, it cannot be turned off unless a reverse voltage is applied. Therefore, the thyristor cannot be used in a DC circuit. However, in this embodiment, a potential difference is generated due to a voltage drop due to an inrush current to the smoothing electrolytic capacitors C1 and C2 inside the second power conditioner 7, and a reverse voltage is generated. The two thyristors 20 and 21 are turned off. Details will be described below.

  First, when the first control signal sigA for turning on is input to the gates of the first and second thyristors 20 and 21 in the state where the IGBT 22 of FIG. Continue until the negative voltage or current is zero. Therefore, as long as there is a power generation output of the second solar cell array 5 and the first power conditioner 4 is operating, current continues to flow without applying a voltage to the gate.

  From this state, when the power generation output of the solar cell is increased and the second power conditioner 7 is operated, the second control signal sigB that is turned on is supplied to the IGBT 22 to turn on the IGBT 22. A voltage is applied to the smoothing electrolytic capacitors C1 and C2 inside the conditioner 7, and an inrush current flows.

  At this time, the second power generation system is substantially at the same potential as the first power generation system because DC power is supplied to the first power conditioner 4 of the first power generation system.

  When the charge current to the electrolytic capacitors C1 and C2 flows in addition to the current supplied to the first power conditioner 4, the second solar cell array 5 always has the first due to the internal resistance of the solar cell. Since the voltage is lower than that of the solar cell array 2 and the voltage of the second power generation system is low due to the characteristics of the thyristor, the current is cut off, and the first and second thyristors 20 and 21 are kept off.

  Next, when the first and second thyristors 20 and 21 are turned on, the emitter side voltage of the IGBT 22 is checked, and it is confirmed that the voltage has surely dropped when the current is cut by the IGBT 22.

  As described above, in this embodiment, on / off of the first and second thyristors 20 and 21 is controlled.

  The present invention can be similarly applied to control of the operation of three or more power conditioners.

  For example, as shown in FIG. 4, a third power generation system as a sub power generation system including a third solar cell array 25, a third junction box 26, and a third power conditioner 27 is added, The positive side 18p and the negative side 18N of the DC power line 18 of the power generation system and the positive side 28P and the negative side 28N of the DC power line 28 of the third power generation system are connected via the third and fourth thyristors 29 and 30. The IGBT 31 may be inserted into the positive electrode side 28P of the DC power line 28 of the third power generation system.

  In the configuration of FIG. 4, when the generated power of the solar cell is high, the first to third power conditioners 4, 7, and 27 are operated. When the generated power of the solar cell is low, the first and first power conditioners are operated. When the two power conditioners 4 and 7 are operated and the generated power of the solar cell is further reduced, the operation is performed with only one of the first power conditioners 4.

  Other configurations are the same as those in FIG.

  In each of the above-described embodiments, the number of operating power conditioners is controlled based on the output power of the first power conditioner 4, but as another embodiment of the present invention, based on the generated power of the solar cell array. In addition, the number of operating inverters may be controlled.

  The present invention is useful for a photovoltaic power generation system in which generated power fluctuates.

1 is a configuration diagram of a photovoltaic power generation system according to an embodiment of the present invention. It is a block diagram of the power conditioner of FIG. It is a time chart used for operation | movement description. It is a block diagram of the solar energy power generation system of other embodiment of this invention. It is a figure which shows the characteristic of a power conditioner. It is a figure for demonstrating a subject.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photovoltaic power generation system 2,5,25 1st, 2nd, 3rd solar cell array 4,7,27 1st, 2nd, 3rd power conditioner 8,8-1 Control device 20,21, 29, 30 1st to 4th thyristor 22, 31 IGBT

Claims (6)

An apparatus for controlling the operation of a plurality of non-insulated power conditioners that are connected to a plurality of DC power sources, convert DC power generated by the DC power sources into AC power, and are linked to a system power source. There,
Among a plurality of sets of power generation systems including a set of the DC power supply and the power conditioner individually connected to the DC power supply, a set of power generation systems is used as a main power generation system, and at least one other set The power generation system of
The positive side and the negative side of the DC power line between the DC power source and the power conditioner of the main power generation system are on the positive side and the negative side of the DC power line between the DC power source and the power conditioner of the sub power system. , Each connected via a unidirectional switching element, a switching element is inserted on the power conditioner side of the DC power line of the sub power generation system from the connection point of the unidirectional switching element,
The unidirectional switching element connecting the positive electrode side is inserted in a direction in which a current flows from the sub power generation system to the main power generation system, while the unidirectional switching element connecting the negative electrode side is the main directional switching element. Inserted in the direction in which current flows from the power generation system to the sub power generation system,
Based on the output power of the power conditioner or the output power of the DC power supply, the number of operating power conditioners is controlled by controlling on / off of the unidirectional switching element and the switching element. The operation control device of the inverter. The DC power source is a solar cell array;
When the output power of the power conditioner of the main power generation system is greater than or equal to a threshold value, the unidirectional switching element connecting the positive electrode side and the negative electrode side is turned off and the switching element is turned on to When the power conditioner of the sub power generation system is operated, and the output power of the power conditioner of the main power generation system is less than the threshold, the unidirectional switching element that connects the positive electrode side and the negative electrode side is The power conditioner operation control device according to claim 1, wherein the power conditioner operation control device is turned on, and the operation of the power conditioner of the sub power generation system is stopped by turning off the switching element. Each of the power conditioners has a smoothing capacitor, and the unidirectional switching element is a thyristor,
When the output power of the power conditioner of the main power generation system is greater than or equal to a threshold, the switching element is turned on when the input voltage of the power conditioner of the sub power generation system is reduced to a predetermined voltage or less. The operation control device for a power conditioner according to claim 2, which is turned on. A plurality of solar cell arrays and a plurality of non-insulated power conditioners respectively connected to the solar cell array, and direct current power generated by the solar cell array is converted into alternating current power by the power conditioner It is a solar power generation system that converts each and connects to the system power supply,
Of a plurality of sets of power generation systems each including the solar cell array and the power conditioner individually connected to the solar cell array, one set of power generation systems is used as a main power generation system, and the other A power generation system of a pair or more is a sub power generation system,
The positive electrode side and the negative electrode side of the DC power line between the solar cell array and the power conditioner of the main power generation system are the positive electrode side and the negative electrode of the DC power line between the solar cell array and the power conditioner of the sub power generation system. Each side is connected via a unidirectional switching element, and a switching element is inserted on the power conditioner side of the DC power line of the sub power generation system from the connection point of the unidirectional switching element,
The unidirectional switching element connecting the positive electrode side is inserted in a direction in which a current flows from the sub power generation system to the main power generation system, while the unidirectional switching element connecting the negative electrode side is the main directional switching element. Inserted in the direction in which current flows from the power generation system to the sub power generation system,
A control device that controls on / off of the unidirectional switching element and the switching element based on the output power of the power conditioner or the output power of the solar cell array to control the number of operating the plurality of power conditioners. A photovoltaic power generation system comprising:   The control device turns off the unidirectional switching element that connects the positive electrode side and the negative electrode side when the output power of the power conditioner of the main power generation system is greater than or equal to a threshold value, and the switching element Is turned on to operate the power conditioner of the sub power generation system, and when the output power of the power conditioner of the main power generation system is less than the threshold value, the unit that connects the positive electrode side and the negative electrode side is connected. The photovoltaic power generation system according to claim 4, wherein the directional switching element is turned on and the switching element is turned off to stop the operation of the power conditioner of the auxiliary power generation system.   Each of the power conditioners has a smoothing capacitor, the unidirectional switching element is a thyristor, and the control device is configured such that the output power of the power conditioner of the main power generation system is equal to or greater than a threshold value. The photovoltaic power generation system according to claim 5, wherein the switching element is turned on when an input voltage of a power conditioner of the sub power generation system is lowered to a predetermined voltage or less.

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