JP2011107904A - Voltage setting device, photovoltaic power generation system, and control method of voltage setting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce loss in DC-DC conversion. <P>SOLUTION: A power converter T11 for setting voltage to a current output from a module MOD11, and externally outputting the current with the voltage is provided with: a DC-DC converter 53 for converting the voltage; a secondary-side voltage/current monitoring unit 56 for detecting power output from the DC-DC converter 53; and a maximum power point control unit 54 for determining voltage set by the DC-DC converter 53 so that output power detected by the secondary-side voltage/current monitoring unit 56 may be maximized. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a voltage setting device that performs DCDC conversion (DC voltage conversion), a control management device, a photovoltaic power generation system, and a control method for the voltage setting device.

  In recent years, solar power generation that uses solar energy, which is clean energy that is environmentally friendly and clean, is drawing attention.

  Here, the components of the solar cell used in the photovoltaic power generation system will be described with reference to FIG.

  As shown in FIG. 12, the solar battery cell SEL1000 that generates current by photoelectric effect when irradiated with sunlight is the minimum unit of the configuration of the solar battery.

  The solar cell module MOD1011 is a unit configured by a plurality of solar cells SEL1000.

  The solar cell string STR1001 is configured by a plurality of solar cell modules MOD1011 connected in series.

  The solar cell array ARR1010 includes a plurality of solar cell strings STR1001 connected in parallel.

  Next, a typical configuration of a photovoltaic power generation system for performing photovoltaic power generation will be schematically described with reference to FIG.

  As illustrated in FIG. 13, the photovoltaic power generation system 1001 includes a solar cell array ARR1010, a power conditioner 1020, and a load 1030.

  The power conditioner 1020 is for converting the DC power output from the solar cell array ARR1010 into AC power by the built-in inverter 1021 and supplying the AC power to the load 1030.

  As shown in FIG. 13, the photovoltaic power generation system 1001 is configured to operate in conjunction with a commercial power system 1040 provided by an electric power company, or independently without being linked to the electric power system 1040 of the electric power company. The system is operated as a system.

  Conventionally, in such a solar power generation system, it has been desired to more efficiently convert solar energy into electric power, and various techniques have been proposed to meet such a demand. In the following, four examples of such techniques are presented.

  First, a technique for operating a solar cell in units of strings at a maximum power point has been proposed (Patent Document 1).

  In addition, a communication device for communicating with the management unit is attached to each PV module (panel), and the operation state of the PV module is transmitted from the attached communication device to the management unit. It has been proposed to transmit a control signal for operation to a communication device (Patent Document 2).

  And in patent document 3, even if solar radiation conditions differ partially, or the direction of an installation place, and a temperature environment differ in a photovoltaic power generation system, switching control is performed for every PV module, and operation | movement is carried out. A technique for obtaining electric power more efficiently by adjusting voltage and current is disclosed.

  Finally, in Patent Document 4, the operating voltage of the inverter is manipulated, and various parameters when the output power of the solar cell reaches the maximum power point are registered in the database. In normal operation, they are registered in the database. It is disclosed that the operating voltage is adjusted on the basis of the parameter being set.

International Publication No. 2006/033142 (A1) Specification (published on March 30, 2006) US Patent Application Publication No. 2009/0150005 (published on June 11, 2009) JP 2007-58845 A (published March 8, 2007) JP 2000-181555 A (published June 30, 2000)

  However, in the conventional technology as described above, although the maximum power can be obtained for each PV module, the output power may be greatly lost when the DCDC conversion is performed. There was a problem that the maximum power could not be obtained as a whole photovoltaic system.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a voltage that can suppress a loss (so-called DCDC conversion loss) when power is output from a voltage change circuit capable of changing the voltage. It is to implement a control method for a setting device, a control management device, a photovoltaic power generation system, and a voltage setting device.

  In order to solve the above-described problems, the voltage setting device according to the present invention can set the voltage with respect to the current output from the solar cell, and can change the voltage in the voltage setting device that outputs the voltage to the outside. Voltage changing circuit, output power detecting means for detecting power output from the voltage changing circuit, and voltage set by the voltage changing circuit so that the output power detected by the output power detecting means is maximized. And voltage determining means for determining.

  In order to solve the above-mentioned problem, the voltage setting device control method according to the present invention sets a voltage for the current output from the solar cell, and controls the voltage setting device that outputs the voltage to the outside. In the method, an output power detection step for detecting power output from a voltage change circuit capable of changing the voltage, and the voltage change circuit is set so that the output power detected in the output power detection step is maximized. And a voltage determining step for determining a voltage to be determined.

  According to the said structure, the output electric power after the direct-current voltage input from the solar cell was output from the voltage change circuit is detectable. The solar cell includes any of a cell that is a photovoltaic power generation element, a cluster or module in which a plurality of cells are connected in series, a string in which modules are connected in series, and an array in which strings are connected in parallel.

  Then, while detecting the power output from the voltage change circuit, the voltage set by the voltage change circuit is determined so that the detected output power becomes maximum.

  For this reason, it is possible to suppress a loss when the voltage is set in the voltage changing circuit and output to the outside with the voltage (so-called DCDC conversion). As a result, it is possible to obtain the maximum output power after being output from the voltage changing circuit, which cannot be obtained simply by maximizing the output of the solar cell. In other words, solar energy can be used efficiently with the above configuration.

  The voltage setting device according to the present invention further includes power measuring means for measuring the power output from the solar battery between the solar battery and the voltage changing circuit, and the voltage determining means is controlled by the power measuring means. After determining the provisional voltage set by the voltage changing circuit so that the measured power is maximized, with the provisional voltage as a reference, the output power detected by the output power detection means is maximized. It is preferable to determine a voltage set by the voltage changing circuit.

  According to said structure, first, the electric power output from the solar cell is measured between a solar cell and a voltage change circuit, and the temporary voltage that this electric power becomes the maximum is determined.

  Since the provisional voltage can be determined by MPPT control, the provisional voltage can be determined relatively quickly.

  Thereafter, the voltage is determined with the provisional voltage as a reference so that the output power detected by the output power detection means is maximized, so that the voltage can be determined more quickly.

  In the voltage setting device according to the present invention, the current output from the solar cell bypasses the voltage change circuit and outputs to the outside, and the current output from the solar cell changes the voltage. It is preferable to further include detour determination means for determining whether to output to the outside via the circuit or to the outside via the detour circuit.

  When a voltage is set in the voltage changing circuit with respect to the current output from the solar cell and the voltage is output to the outside with the set voltage, power loss occurs.

  According to the above configuration, it is provided with a bypass circuit for bypassing the voltage change circuit and outputting to the outside, and the current output from the solar cell is output to the outside via the voltage change circuit, Whether to output to the outside through the bypass circuit can be determined.

  Therefore, current can be output to the outside via a bypass circuit as necessary.

  In this manner, by outputting the current to the outside via the bypass circuit as necessary, there is an effect that it is possible to prevent power loss in the voltage changing circuit.

  In the voltage setting device according to the present invention, the detour determination means outputs to the outside via the voltage change circuit based on at least one of temperature and solar radiation intensity in the solar cell, or externally via the detour circuit. It is preferable to determine whether to output to.

  According to the above configuration, whether to output to the outside via the voltage change circuit or to the outside via the bypass circuit is determined based on at least one of the temperature and solar radiation intensity in the solar cell.

  As described above, when the current is output to the outside through the voltage change circuit, power loss is caused in the voltage change circuit. Therefore, even if the voltage is not changed, when sufficiently large power is obtained from the solar cell, the current is output to the outside through the bypass circuit in order to prevent the power loss in the voltage change circuit. It is more preferable.

  Here, the characteristics of the solar cell will be described as follows.

  When the temperature in the solar cell rises, the voltage in power generation drops due to the characteristics of the solar cell. Moreover, the solar radiation intensity in a solar cell influences the power generation efficiency of a solar cell. That is, as the solar radiation intensity increases, the power output from the solar battery tends to increase, and as the solar radiation intensity decreases, the power output from the solar battery tends to decrease.

  That is, the magnitude of power can be estimated using the temperature and solar radiation intensity in the solar cell without directly measuring the magnitude of power from the solar cell.

  Thereby, for example, the current can be output to the outside via the bypass circuit instead of the voltage changing circuit as necessary. That is, if the solar radiation intensity is strong, the current may be output to the outside via the bypass circuit, and if the temperature is high, the current may be output to the outside via the voltage changing circuit.

  As a result, although there is a high possibility that the electric power from the solar cell is sufficiently large, there is an effect that it is possible to prevent the electric power from being lost due to passing through the voltage changing circuit without any darkness.

  The voltage setting device according to the present invention further includes power measuring means for measuring the power output from the solar battery between the solar battery and the voltage changing circuit or the bypass circuit, wherein the bypass determining means is It is preferable to determine whether to output to the outside via the voltage changing circuit or to the outside via the bypass circuit based on the power measured by the power measuring means.

  As described above, when sufficiently large power is obtained from the solar cell without changing the voltage, the current is sent to the outside through the detour circuit in order to prevent the power loss in the voltage change circuit. It is more preferable to output.

  According to the above configuration, first, the power output from the solar cell is measured. Based on the measured power, the current is output to the outside through the voltage changing circuit or output to the outside through the detour circuit. You can decide what to do.

  Therefore, whether the current output path is the voltage changing circuit or the bypass circuit can be determined depending on whether or not sufficiently large electric power is obtained from the solar cell.

  For this reason, there is an effect that it is possible to prevent the power from being lost by passing through the voltage changing circuit even though sufficiently large power is obtained from the solar cell.

  In the voltage setting device according to the present invention, between the solar cell and the voltage changing circuit or the bypass circuit, power measuring means for measuring the power output from the solar cell, and outputting a voltage to the outside A short-circuit switching circuit that switches between the two output terminals to be switched between a short-circuited state and a non-short-circuited state; and a short-circuit determining unit that determines whether to switch the short-circuit switching circuit to a short-circuited state, It is preferable that the short-circuit determining unit determines to switch the short-circuit switching circuit to the short-circuited state when the power measured by the power measuring unit is equal to or less than a predetermined value.

  When the voltage setting device to which the solar cells are connected is connected in series, if the output power is reduced in a certain solar cell, the output power of other solar cells may be greatly reduced.

  According to the above configuration, the power output from the solar cell is measured, and the state of the short circuit switching circuit is switched based on the measured power. Therefore, when the output of the solar cell is reduced, the solar cell Can be bypassed on the circuit, and the current input from one connected voltage setting device can be output to the other voltage setting device. As a result, solar cells that may affect the output power of other solar cells as a whole can be removed on the circuit.

  Thereby, there exists an effect that it can prevent that the solar cell in which the output has fallen affects the output electric power of the other solar cell whole.

  In addition, the current that flows in a short-circuited state is only in one direction and has a backflow prevention function, and usually a backflow prevention element installed in the junction box is unnecessary.

  The voltage setting device according to the present invention further includes receiving means for receiving array output power data indicating the output power of the solar cell array via a communication network, wherein the detour determination means is based on the array output power data. It is preferable to determine whether to output to the outside via the voltage change circuit or to the outside via the bypass circuit.

  According to the above configuration, the array output power data indicating the output power of the solar cell array including the solar cells is received, and the output power of the solar cell array indicated by the received array output power data is passed through the detour circuit. It can be determined whether or not the current is output to the outside.

  In this manner, by outputting the current to the outside via the bypass circuit as necessary, there is an effect that it is possible to prevent power loss in the voltage changing circuit.

The voltage setting device according to the present invention further comprises receiving means for receiving the array output power data indicating the output power of the solar cell array via the communication network,
The short-circuit determining means determines whether or not the power measured by the power measuring means satisfies a predetermined standard based on the ratio of the power measured by the power measuring means and the power indicated by the array output power data. It is preferable.

  According to the said structure, short circuit control can be performed based on the ratio of the electric power of a solar cell, and the electric power of the solar cell array containing this solar cell. Since the short circuit control is performed based on the ratio of the power of the solar cell to the power of the entire solar cell array, for example, when the output of the solar cell is extremely low in the entire solar cell array, the short circuit switching circuit Can be controlled to be in a short-circuited state.

  The voltage setting device according to the present invention preferably includes transmission means for transmitting power data indicating the output power detected by the output power detection means.

  In order to solve the above-described problems, a control management apparatus according to the present invention has a power data receiving unit that receives power data and a maximum output power indicated by the power data received by the power data receiving unit. Voltage determining means for determining a voltage, and control data transmitting means for transmitting the voltage determined by the voltage determining means are provided.

  According to the above configuration, the control management device can determine the voltage based on the power data transmitted from the voltage setting device so as to maximize the output power output from the voltage setting device to the outside. For this reason, the voltage setting device can maximize the power output from the voltage changing circuit in accordance with the voltage determined by the control management device. In other words, solar energy can be used efficiently with the above configuration.

  In addition, by appropriately combining the voltage setting device according to the present invention and the control management device, it is possible to realize a photovoltaic power generation system including the voltage setting device and the control management device, The solar power generation system also falls within the scope of the present invention.

  The voltage setting device according to the present invention includes a voltage changing circuit capable of changing a voltage, output power detecting means for detecting power output from the voltage changing circuit, and output power detected by the output power detecting means being maximum. And voltage determining means for determining a voltage set by the voltage changing circuit.

  Further, the control method of the voltage setting device according to the present invention includes an output power detection step for detecting power output from a voltage change circuit capable of changing voltage, and the output power detected in the output power detection step is maximum. And a voltage determining step for determining a voltage set by the voltage changing circuit.

  Therefore, it is possible to obtain the maximum output power after being output from the voltage change circuit, which could not be obtained simply by maximizing the output of the solar cell, while suppressing the loss of power output from the voltage change circuit. There is an effect of becoming.

  The control management device according to the present invention includes a power data receiving unit that receives output power detected by the power detection unit of the voltage setting device from the voltage setting device, and a power data received by the power data receiving unit. Voltage determining means for determining the voltage of the voltage setting device so that the output power indicated by the reference voltage is maximized, and control data transmitting means for transmitting the voltage determined by the voltage determining means to the voltage setting device. Features.

  According to the above configuration, the control management device can determine the voltage based on the power transmitted from the voltage setting device so as to maximize the output power output from the voltage setting device to the outside. For this reason, the voltage setting device can maximize the power output from the voltage changing circuit in accordance with the voltage determined by the control management device.

It is a functional block diagram shown about the structural example of the module which concerns on one Embodiment of this invention, and an output converter. It is a functional block diagram which shows the schematic structure of the solar energy power generation system which concerns on one Embodiment of this invention. It is a table for demonstrating the relationship between the output of a module, the electric power loss which arises by DCDC conversion, and the output of the secondary side of an output converter. It is the flowchart shown about the flow of the process in the output converter which concerns on one Embodiment of this invention. It is the graph shown about the IV characteristic of the string in case each module which comprises a string has acquired sufficient solar radiation amount. It is the graph shown about the IV characteristic of a string in case one module is shaded among the three modules which comprise a string, and output current is falling. It is the graph which showed the IV characteristic of the string in case two modules are shaded among the three modules which comprise a string, and the output current is falling. It is a block diagram shown about the structural example in the case of connecting an output converter to a cluster. It is a block diagram which shows schematic structure of the solar energy power generation system which concerns on other embodiment of this invention. It is a block diagram which shows schematic structure of the solar energy power generation system which concerns on another embodiment of this invention. It is a block diagram which shows schematic structure of the solar energy power generation system which concerns on other embodiment of this invention. It is a schematic diagram shown about the relationship of the conventional solar cell array, a solar cell string, a solar cell module, and a photovoltaic cell. It is the block diagram shown about the schematic structure of the conventional solar power generation system.

[Embodiment 1]
An embodiment of the present invention will be described below with reference to FIGS.

(About the configuration of the photovoltaic power generation system)
First, the schematic configuration of the photovoltaic power generation system according to the present embodiment will be described with reference to FIG.

  As shown in FIG. 2, the photovoltaic power generation system 1 includes a solar cell array (hereinafter simply referred to as an array) ARR 11, a power conditioner 20, and a load 30.

  The array ARR11 is a unit formed by connecting a plurality of solar cell strings (hereinafter simply referred to as strings) STR11 to STR14 in a connection box 45 in parallel. In FIG. 2, in the photovoltaic power generation system 1, only one array ARR <b> 11 is shown for convenience of explanation, but of course, a configuration including a plurality of arrays may be used.

  Each of the strings STR11 to STR14 is a block configured by connecting a plurality of solar cell modules (hereinafter simply referred to as modules) in series. The string STR11 includes modules MOD11 to MOD13.

  Note that the strings STR12 to STR14 have the same configuration as the configuration of the string STR11 described above, and thus the description thereof is omitted in FIG. Moreover, the structure of the same figure is only one structural example of the photovoltaic power generation system 1 until it gets tired, and the number of strings included in the array ARR11 is not limited to four of the strings STR11 to STR14.

  Modules MOD11 to MOD 13 are obtained by arranging a plurality of solar cells (hereinafter simply referred to as cells).

  The output converters (voltage setting devices) T11 to T13 perform DCDC conversion (DC voltage conversion) on the electric power input from the primary side S1 and output it to the secondary side S2.

  In FIG. 2, the output converters T11 to T13 are connected to the modules MOD11 to MOD13, respectively.

  The connection relationship between the output converters T11 to T13 and the modules MOD11 to MOD13 will be described as follows by taking the output converter T11 as an example. That is, the primary-side positive electrode S1 + of the output converter T11 is connected to the positive electrode of the module MOD11, and the primary-side negative electrode S1- is connected to the negative electrode of the module MOD11.

  The power output from the positive electrode of the module MOD11 is input to the primary side S1 of the output converter T11, DCDC converted in the output converter T11, and output to the secondary side S2 of the output converter T11.

  Note that the module connection relationship between the output converter T12 and the output converter T13 is the same as the module connection relationship of the output converter T11 described above, and a description thereof will be omitted.

  The connection relationship between the output converters T11 to T13 is as follows.

  First, the secondary negative electrode S2- of the output converter T11 is connected to the junction box 45, and the secondary positive electrode S2 + is connected to the secondary negative electrode S2- of the output converter T12.

  The secondary positive electrode S2 + of the output converter T12 is connected to the secondary negative electrode S2- of the output converter T13, and the secondary positive electrode S2 + of the output converter T13 is connected to the connection box 45. Yes.

  The power conditioner 20 is for adjusting the power output from the array ARR11 so that it can be supplied to the load 30.

  The solar power generation system 1 may include a commercial power system 40 and may be configured to be linked to the commercial power system 40 or may be configured to operate independently without being linked to the commercial power system. Also good.

  The load 30 is a target to which power is supplied, and is typically an electric device that is to be operated by supplying power.

(Module and output converter)
Below, the structural example of module MOD11 and output converter T11 is demonstrated using FIG.

[module]
As illustrated in FIG. 1, the module (solar cell) MOD11 includes three clusters CLS11 to CLS13.

  The cluster CLS11 is a unit having six cells SEL111 to SEL116 and a bypass diode 43A as one unit.

  The cells SEL111 to SEL116 are connected in series. Further, a bypass diode 43A is provided in parallel with the cells SEL111 to SEL116.

  The bypass diode 43A bypasses the current flowing through the cluster CLS11 when any one of the six cells SEL111 to SEL116 included in the cluster CLS11 decreases for some reason, and normally generates power in other clusters. It is for making it possible.

  Note that the cluster CLS12 and the cluster CLS13 have the same configuration as the cluster CLS11, and thus the description thereof is omitted. The clusters CLS11 to CLS13 are connected in series in the terminal box 41.

[Output converter]
The output converter T11 will be described with reference to FIG.

  The output converter T11 is for DCDC conversion of the output of the module MOD11. The output converter T11 includes a DCDC short circuit switch (bypass circuit) 51, a module short circuit switch (short circuit switching circuit) 52, a DCDC converter (voltage change circuit) 53, a maximum operating point control unit (voltage determination means, bypass determination means, short circuit). A determination unit) 54, a primary side voltage / current monitoring unit (power measurement unit) 55, and a secondary side voltage / current monitoring unit (output power detection unit) 56.

  The DCDC short-circuit switch 51 bypasses the DCDC conversion unit 53 and transfers the power input from the module MOD11 to the primary side S1 when the output of the module MOD11 is sufficient without performing DCDC conversion. It is for outputting to S2.

  The DCDC short-circuit switch 51 is connected to the primary-side positive electrode S1 + and the secondary-side positive electrode S2 +, and opens between the primary-side positive electrode S1 + and the secondary-side positive electrode S2 + in the off state. In addition, the DCDC short-circuit switch 51 forms a circuit that short-circuits between the primary-side positive electrode S1 + and the secondary-side positive electrode S2 + while bypassing the DCDC converter 53 in the on state.

  The on / off control of the DCDC short-circuit switch 51 is performed by the maximum operating point control unit 54, and details thereof will be described later.

  The module short-circuit switch 52 is a switch for disconnecting the module MOD11 from the circuit when the input power from the module MOD11 is equal to or lower than a predetermined value.

  The predetermined value is, for example, a power value at which the input power is too small to perform DCDC conversion, or a power value at which the input power is too small to provide sufficient output even after DCDC conversion. It can be determined based on the value.

  The module short-circuit switch 52 is connected to the secondary negative electrode S2- and the secondary positive electrode S2 +, and in the off state, releases the space between the secondary negative electrode S2- and the secondary positive electrode S2 +. Further, in the ON state, the module short-circuit switch 52 short-circuits between the secondary-side negative electrode S2- and the secondary-side positive electrode S2 +, and disconnects the module MOD11 from the circuit in the string.

  The on / off control of the module short-circuit switch 52 is performed by the maximum operating point control unit 54, details of which will be described later.

  The DCDC converter 53 is for DCDC conversion of the voltage of the power input from the module MOD11 to the primary side S1 under the control of the maximum operating point control unit 54, and outputs it to the secondary side S2.

  The primary side voltage / current monitoring unit 55 measures the output voltage / output current of the module MOD11, and maximizes the input voltage on the S1 side derived from the measured output voltage / output current of the module MOD11 or the output voltage / output current. The operating point control unit 54 is notified.

  The secondary side voltage / current monitoring unit 56 measures the output voltage / output current of the secondary side S2 of the output converter T11, and the measured output voltage / output current of the secondary side S2 of the output converter T11 or the output thereof. The output power of the secondary side S2 derived from the voltage / output current is notified to the maximum operating point control unit 54.

  The maximum operating point control unit 54 outputs the output of the secondary side S2 of the output converter T11 based on the output voltage / output current measured by the primary side voltage / current monitoring unit 55 and the secondary side voltage / current monitoring unit 56, respectively. Is controlled to be maximized. That is, the maximum operating point control unit 54 adjusts the output voltage / output current of the module MOD11 so that the output of the secondary side S2 is maximized.

  Specifically, the maximum operating point controller 54 controls the DCDC converter 53 so as to perform DCDC conversion with a Duty value that maximizes the output of the secondary side S2 of the output converter T11.

  First, the maximum operating point control unit 54 operates the module MOD11 by MPPT (Maximum Power Point Tracking) control so that the output of the primary side S1 becomes maximum, and then the output of the secondary side S2 becomes maximum. You may control so.

  Since the operating point of the module MOD11 when the output of the secondary side S2 is maximum is in the vicinity of the maximum operating point of the module MOD11, the time until the operating point where the output of the secondary side S2 is maximum is thereby reached. Can be shortened.

  Further, the maximum operating point control unit 54 includes a DCDC short circuit switch 51 and a module short circuit switch 52 based on the output voltage / output current measured by the primary side voltage / current monitoring unit 55 and the secondary side voltage / current monitoring unit 56, respectively. Control the opening and closing of.

  Note that the configurations of the modules MOD12 and MOD13 and the output converters T12 and T13 are the same as the configurations of the module MOD11 and the output converter T11 described above, and thus the description thereof is omitted.

  The configuration described above is merely an example, and the design of the configurations of cells, clusters, modules, strings, and arrays can be changed as appropriate.

(Solar cell characteristics)
Here, the characteristics of the solar cell will be described as follows. If part of the module MOD11 is covered in the shade and the output power of the part covered by the shade is reduced, the power generation efficiency of the entire module is greatly affected, and the output power of the part is more than the reduction. It is known that overall power generation is reduced.

  For example, one or more of the cells SEL111 to SEL116 are partially or entirely covered with the shade, so that the output power of the cell decreases. Thereby, the decrease in the output of the module MOD11 may be larger than the decrease in the output power of the cell.

  Similarly, it is known that if a certain module causes a decrease in output in the string, it greatly affects the entire power generation amount of the string.

(Specific example of control of maximum operating point control unit)
[Control to operate at maximum operating point]
DCDC conversion involves power loss. The width of loss varies depending on the state of input / output control in DCDC conversion. Therefore, in the conventional maximum operating point tracking control (hereinafter referred to as MPPT control), even if the maximum output is obtained for each module, the output after DCDC conversion may be larger when the operation is not performed at the maximum operating point. is there.

  Therefore, the maximum operating point control unit 54 outputs the output of the secondary side S2 as follows when the power output by the module MOD11, that is, when the input power of the primary side S1 is a predetermined power or more. Control to maximize the power.

  That is, the maximum operating point control unit 54 varies the duty value within a range in which DCDC conversion is possible, so that the DCDC conversion unit 53 performs DCDC conversion at a duty value at which the output power of the secondary side S2 becomes maximum. Control. That is, the maximum operating point control unit 54 sets a voltage that maximizes the output power of the secondary side S2, and controls the DCDC conversion unit 53 to perform DCDC conversion with the set voltage.

  At this time, the maximum operating point control unit 54 operates the module MOD11 by MPPT control so that the input power of the primary side S1 becomes maximum, and the output power of the secondary side S2 becomes maximum with reference to this operating point. The Duty value may be searched.

  That is, the maximum operating point control unit 54 operates the DCDC converter 53 with a temporary voltage, sets a voltage that maximizes the output power of the secondary side S2, and performs DCDC conversion with the set voltage. The unit 53 may be controlled to perform DCDC conversion.

  As a result, it is possible to more quickly determine the voltage that maximizes the output power of the secondary side S2.

  Hereinafter, an example of control by the maximum operating point control unit 54 will be described with reference to FIG.

  The relationship between the output of the module MOD11, the power loss caused by DCDC conversion, and the output on the secondary side of the output converter T11 can be expressed by the following equation (1).

  That is, the output on the secondary side of the output converter can be obtained by the following equation (1).

[Secondary output of output converter] = [Output of module (primary side input of output converter)] − [Power loss in output converter] (1)
The power loss in the output converter is a power loss at the time of DCDC conversion in the DCDC converter 53.

  As shown in the equation (1), even if the output of the module MOD11 is maximum, if the power loss in the output converter T11 is large, the output of the secondary side S2 of the output converter T11 is not necessarily maximum. .

  That is, to increase the output of the secondary side S2 of the output converter T11, the power loss in the output converter T11 must be reduced while increasing the output of the module MOD11.

  FIG. 3 shows a case where the outputs of the module MOD11 are “10”, “9”, and “8”. Each value in FIG. 3 is a value in which the maximum output power of the module MOD11 is “10”, but the loss value of the output converter T11 varies depending on the input / output state of the DCDC conversion, and is not necessarily shown in FIG. Not street. In FIG. 3, the output of the module MOD11 is “10”, and is “9” and “8” in order.

  The power loss caused by the DCDC conversion is “4” when the output of the module MOD11 is “10”, and “2” when the output of the module MOD11 is “9” and “8”, respectively. And “3”.

  Then, from the calculation of equation (1), when the output of the module MOD11 is “10”, the output on the secondary side of the output converter is “6”, whereas the output of the module MOD11 is “9”. In this case, the output on the secondary side of the output converter is “7”. As a result, the output on the secondary side of the output converter is “6” and the output of the module MOD11 is “10”. Rather than a large output.

  In this case, the module MOD11 itself operates at the maximum operating point and an output “10” is obtained, but the output after DCDC conversion in the output converter T11 is not maximum.

  Therefore, the maximum operating point control unit 54 controls the module MOD11 so as to obtain the output “9” by changing the duty value with reference to the operating point at which the output “10” is obtained. Thereby, the maximum output “7” after DCDC conversion can be obtained.

  When the output of the module MOD11 is “8”, the output on the secondary side of the output converter is “5”, and among these, the output on the secondary side of the output converter is the smallest.

[Control of DC / DC short-circuit switch]
As described above, since the DCDC conversion involves power loss, if the module has a sufficient output that does not require DCDC conversion, it is rather preferable not to perform DCDC conversion. This is preferable from the viewpoint of the power generation efficiency of the system.

  This is because if the output from the module MOD11 is DCDC converted, an output loss due to the DCDC conversion occurs, and as a result, the output of the output converter T11 may be smaller than when the DCDC conversion is not performed. It is.

  Therefore, the maximum operating point control unit 54 is sufficient so that the output of the module MOD11 does not need to perform DCDC conversion based on the measured values such as the primary side voltage / current and the secondary side voltage / current. If it is determined that the output of the module MOD11 is sufficient to avoid the DCDC conversion, the DCDC short-circuit switch 51 is turned on so that the DCDC conversion can be bypassed. To.

  On the other hand, when it is determined that the output of the module MOD11 needs to perform DCDC conversion, the maximum operating point control unit 54 turns off the DCDC short-circuit switch 51 so as to perform DCDC conversion.

  In addition, the maximum operating point control unit 54 can determine from various viewpoints whether or not the output of the module MOD11 is sufficient to avoid performing DCDC conversion.

  For example, when the output power of the module is equal to or higher than a predetermined ratio of the nominal maximum output of the module, the maximum operating point control unit 54 is sufficient to prevent the output of the module MOD11 from performing DCDC conversion. You may determine that there is.

  Further, in the case where a solar radiation meter that measures the solar radiation intensity is provided in the vicinity of the module MOD11, the maximum operating point control unit 54 receives the measurement value of the solar radiation meter, and based on the received measurement value, the module MOD11. When all the cells SEL111 to 116 are not shaded and it is determined whether or not sufficient sunlight irradiation is obtained by determining whether or not sunlight irradiation is obtained, DCDC conversion is performed. It may be determined that it is not necessary to perform.

  Further, the maximum operating point control unit 54 may further determine whether or not the performance degradation of the cells SEL111 to 116 such as a failure has occurred.

  Even if all of the cells SEL111 to 116 of the module MOD11 are not shaded, if it is determined that the performance of the cells SEL111 to 116 is deteriorated, the maximum operating point control unit 54 determines that the cells SEL111 to 116 are sufficient. DCDC conversion is performed assuming that no power is output. On the other hand, when all of the cells SEL111 to 116 of the module MOD11 are not shaded, the maximum operating point control unit 54 performs DCDC conversion when determining that the performance deterioration of the cells SEL111 to 116 has not occurred. Judge that it is not necessary.

  Thus, when it can be determined that the output of the module MOD11 is sufficient to avoid the need for DCDC conversion, power generation efficiency can be improved by not performing DCDC conversion.

[Control of module short-circuit switch]
In the output converter T11, if the module MOD11 can obtain only power that cannot be DCDC converted, the power generation efficiency of the entire string STR11 is improved by separating the module MOD11 from the circuit of the string STR11. is there.

  Therefore, the maximum operating point control unit 54 determines whether or not the output of the module MOD11 is so small that DCDC conversion cannot be performed. When it is determined that the output of the module MOD11 is so small that DCDC conversion cannot be performed, the maximum operating point control unit 54 turns on the module short-circuit switch 52 to turn the module MOD11 into the circuit of the string STR11. Disconnect from above.

  As a case where the output of the module MOD11 cannot be DCDC converted, specifically, for example, the following case is assumed.

  First, there is a case where most of the cells SEL111 to 116 of the module MOD11 are shaded so that the output of the module MOD11 is extremely lowered.

  Further, there is a case where the module MOD11 is disconnected due to a failure or the like.

  In such a case, the module short-circuit switch 52 short-circuits between the secondary-side negative electrode S2− and the secondary-side positive electrode S2 + and bypasses the module MOD11, thereby connecting other output converters T12 to T12 connected in series. 13 is prevented from affecting the output.

(Process flow)
Next, the flow of processing executed in the output converter T11 will be described with reference to FIG.

  First, in the output converter T11, the maximum operating point control unit 54 calculates the output supplied from the module MOD11 from the primary side output voltage / output current notified from the primary side voltage / current monitoring unit 55, and calculates It is determined whether or not the obtained power is a predetermined power or more (S11).

  Here, when the output supplied from the module MOD11 is not equal to or higher than the predetermined power (NO in S11), the maximum operating point control unit 54 turns on the module short-circuit switch 52 and turns on the secondary side negative electrode S2-2 The secondary positive electrode S2 + is short-circuited (S13). Then, after a predetermined period, the process is restarted from S11.

  On the other hand, when the output supplied from the module MOD11 is a predetermined power or higher (YES in S11), the maximum operating point control unit 54 turns off the module short-circuit switch 52 (S12).

  Subsequently, the maximum operating point control unit 54 causes the primary side voltage / current monitoring unit 55 and the secondary side voltage / current monitoring unit 56 to measure the primary side voltage / current and the secondary side voltage / current, respectively. Then, the output power on the primary side and the output power on the secondary side are monitored. Then, the maximum operating point control unit 54 changes the duty value of the DCDC converting unit 53 to operate the module MOD11 by MPPT control (S14).

  Here, the maximum operating point control unit 54 determines whether the output power on the primary side is equal to or greater than a predetermined ratio of the nominal maximum output of the module MOD11 (S15).

  If the output of module MOD11 is equal to or greater than a predetermined ratio of the nominal maximum output (YES in S15), maximum operating point control unit 54 turns on DCDC short-circuit switch 51 to turn on primary-side positive electrode S1 + and secondary-side positive electrode S2 +. Are short-circuited (S16).

  Then, after a predetermined period, the process is restarted from S15.

  On the other hand, if the output of the module MOD11 is not equal to or greater than the predetermined ratio of the nominal maximum output (NO in S15), the DCDC short-circuit switch 51 is left in the off state and causes the DCDC converter 53 to perform DCDC conversion. Here, the maximum operating point control unit 54 controls the duty value of the DCDC conversion unit 53 so as to maximize the output on the secondary side, thereby causing the DCDC conversion unit 53 to perform DCDC conversion (S17).

  Then, after a predetermined period, the process is restarted from S11.

  Note that the reason for returning from the process of S16 to the process of S15 without returning to the process of S11 is that the output of the module MOD11 is determined to be equal to or greater than a predetermined ratio of the nominal maximum output in the process of S15 immediately before. This is because there is no need to determine whether the module short-circuit switch is on or off if there is no significant output drop.

  However, the present invention is not limited to this, and the process of S16 may be returned to the process of S11.

  In S15, whether the DCDC short-circuit switch 51 is turned on or off is determined based on whether the output of the module MOD11 is equal to or higher than a predetermined ratio of the nominal maximum output. However, the present invention is not limited to this. You may judge by.

  For example, control may be performed such that the DCDC short-circuit switch is turned on when the Duty value becomes equal to or greater than a predetermined value.

  In addition, in the output converter T11, when a solar radiation sensor for detecting the solar radiation intensity is provided to monitor the solar radiation intensity, and when the solar radiation intensity fluctuates (decreases) by a predetermined value or more after the DCDC short-circuit switch is turned on. The DCDC short-circuit switch may be controlled to be turned off.

  In the processing of S17, the output on the secondary side may be calculated by measuring the voltage and current on the secondary side and taking the product of the voltage and current, or the output on the primary side and the DCDC converter 53. May be calculated based on the duty value when DCDC conversion is performed.

  Although the output power on the primary side is calculated from the output voltage and output current on the primary side, the present invention is not limited to this.

(About IV characteristics of strings)
Next, using FIG. 5 to FIG. 7, the IV characteristics of the conventional string and the IV characteristics of the string STR11 including the output converters T11 to T13 and the modules MOD11 to MOD13 according to the present invention are compared. To do.

[IV characteristics of string 1]
First, the IV characteristic of the string STR11 when each module constituting the string STR11 obtains a sufficient amount of solar radiation will be described with reference to FIG.

  A curve M11 shown in FIG. 5 is an IV characteristic of one module, a curve M12 is an IV characteristic of two modules connected in series, and a curve M13 is an equivalent of three modules connected in series. Each of the IV characteristics is shown.

  Here, the modules MOD11 to MOD13 each perform power output at the maximum output operating point by MPPT control, and as a result, the maximum output operating point of the string STR11 is the operating point P1max.

  A rectangular area formed by the origin O and the operating point P1max is the output power W10 of the string STR11.

[IV characteristics of string 2]
Next, with reference to FIG. 6, the IV characteristics of the string in the case where one of the three modules constituting the string is shaded and the output current is reduced will be described.

  The example illustrated in FIG. 6 illustrates a case where the output current of one module among the modules MOD11 to MOD13 is reduced due to reasons such as shade. In the figure, a curve composed of a curve M13A and a curve M12 shows the IV characteristics of three modules connected in series.

  Conventionally, the operating point control is performed on a curve composed of the curve M13A and the curve M12.

  In the example shown in FIG. 6, the MPPT control is performed on the curve composed of the curve M13A and the curve M12, and as a result, control is performed to operate at the operating point P21prev indicating the maximum output. However, the output power obtained is limited to W2prev.

  As for the operating state of each module when W2prev is obtained, only the module with normal output current characteristics operates at the maximum operating point to generate power, and the module with reduced output current does not generate power at all. It is in a state.

  On the other hand, the output converter T13 according to the present invention performs DCDC conversion even when the current output of the module MOD13 decreases, so that not only a normal module but also a module whose output current is decreased. Electric power can be obtained. That is, it is possible to obtain an output that is not on the curve composed of the curve M13A and the curve M12.

  In the present invention, since an output can be obtained at P2max, an output larger than the output at the operating point P21prev can be obtained.

  That is, even if the output is reduced due to the reason that the module MOD13 is shaded or the like, if the output on the secondary side becomes larger when operating at the operating point P2max by DCDC conversion, the maximum operating point control is performed. The unit 54 performs control so that it can operate at the operating point P2max. Thereby, output power W20 can be obtained.

  Note that the relationship between the voltage value at P2max in FIG. 6 and the voltage value at P1max in FIG. 5 is supplemented as follows.

  The voltage value at P2max in FIG. 6 is determined in relation to the voltages of other strings connected in parallel.

  Therefore, depending on the voltage values of other strings connected in parallel, the voltage value at P2max may not be the same as the voltage value at P1max in FIG.

  On the other hand, it is also possible to perform DC-DC conversion so that the voltage value at P2max in FIG. 6 is the same as the voltage value at P1max in FIG. For example, the DCDC conversion may be performed so that the voltage value of the other string becomes the voltage value at P1max.

[IV characteristics of string 3]
Next, with reference to FIG. 7, the IV characteristics of the string in the case where two of the three modules constituting the string are shaded and the output current is reduced will be described.

  The example shown in FIG. 7 shows a case where the output currents of the two modules are reduced among the modules MOD11 to MOD13 due to reasons such as shade. In the figure, a curve composed of curves M11, M12A, and M13A shows the IV characteristics of three modules connected in series.

  Conventionally, the operating point control is performed on the curve formed by the curves M11, M12A, and M13A.

  In the example illustrated in FIG. 7, the MPPT control is performed on the curve including the curves M11, M12A, and M13A, and as a result, control is performed so as to operate at the operating point P32prev indicating the maximum output. For this reason, the output power stayed at W3prev at best.

  On the other hand, each of the output converter T12 and the output converter T13 according to the present invention performs the DCDC conversion even if the current output of the module MOD12 and the module MOD13 is decreased, and thereby curves M11, M12A, and M13A. An output P3max can be obtained at an operating point not on the curve consisting of Thereby, output power W30 larger than W3prev can be obtained.

  The relationship between the voltage value at P3max in FIG. 7 and the voltage value at P1max in FIG. 5 is the same as the relationship between the voltage value at P2max in FIG. 6 supplemented above and the voltage value at P1max in FIG. Since it is, the description is omitted.

(Action / Effect)
As described above, the output converter T11 according to the present invention sets the voltage with respect to the current output from the module MOD11, and in the output converter T11 that outputs the voltage to the outside, the DCDC that can change the voltage. The converter 53, the secondary side voltage / current monitoring unit 56 for detecting the power output from the DCDC converter 53, and the DCDC so that the output power detected by the secondary side voltage / current monitoring unit 56 is maximized. And a maximum operating point control unit 54 that determines a voltage to be set in the conversion unit 53.

  As a result, the DCDC conversion loss is suppressed, and the maximum output power after DCDC conversion, which cannot be obtained simply by maximizing the output of the module MOD11, can be obtained.

(Modification)
Below, the preferable modification of output converter T11 which concerns on this embodiment is demonstrated.

[Modification of output converter]
The DCDC short circuit switch 51 and the module short circuit switch 52 of the output converter T11 can be realized by a known technique such as a relay, a diode, or a MOS. Further, the mounting position in the output converter can be arbitrarily set. For example, the output converter T11 may be incorporated in a junction box on the back side of the module, or may be externally attached from the junction box.

  Further, the control cycle of the maximum operating point control unit 54 may be variable. Thereby, it can prevent receiving the influence of the voltage / current control which other output converters T12-T13 connected in series with the output converter T11 perform. That is, by shifting the voltage / current control cycles executed by the output converters T11 to T13 from each other, it is possible to prevent the controls executed by the output converters T11 to T13 from affecting each other.

[Modification of output converter connection]
Next, a modified example of the connection of the output converter T11 will be described with reference to FIG.

  Differences between the configuration example shown in FIG. 2 and the configuration example shown in the present modification will be briefly described as follows.

  In the configuration example shown using FIG. 2, the output converters T11 to T13 are provided in units of modules. On the other hand, in this modified example, as shown in FIG. 8, output converters T11 to T13 are provided in units of clusters (solar cell clusters).

  This modification will be described in detail as follows.

  As illustrated in FIG. 8, the module MOD21 includes output converters T11 to T13 and clusters CLS11 to CLS13 including six cells.

  The cluster CLS11 is a unit composed of six cells SEL111 to SEL116 connected in series. Similarly, the cluster CLS12 is a unit composed of cells SEL121 to SEL126 connected in series, and the cluster CLS13 is a unit composed of cells SEL131 to SEL136 connected in series.

  The output converter T11 will be described as an example. The primary negative electrode S1- of the output converter T11 is connected to the negative electrode of the cluster CLS11, that is, the cell SEL111. The primary side positive electrode S1 + of the output converter T11 is connected to the positive electrode of the cluster CLS11, that is, the cell SEL116.

  Note that the cluster connection relationship between the output converter T12 and the output converter T13 is the same as the cluster connection relationship of the output converter T11 described above, and a description thereof will be omitted.

  The connection relationship between the output converters T11 to T13 is as follows.

  First, the secondary negative electrode S2- of the output converter T11 is connected to the module input Pow21 of the module MOD21, and the secondary positive electrode S2 + is connected to the secondary negative electrode S2- of the output converter T12. .

  The secondary side positive electrode S2 + of the output converter T12 is connected to the secondary side negative electrode S2- of the output converter T13, and the secondary side positive electrode S2 + of the output converter T13 is connected to the module output Pow22 of the module MOD21. It is connected.

  The output converters T11 to T13 may be connected to each other in the connection box 47.

  According to the configuration according to the modified example, in addition to reducing power loss caused by some clusters having reduced power generation capacity affecting other clusters in the same module, the output converter T11-13 can play the role of the bypass diodes 43A-43C existing in the configuration of the module MOD11 shown in FIG.

  Thereby, the bypass diodes 43A to 43C are unnecessary on the circuit.

  As described above, the output converters T <b> 11 to T <b> 13 are not limited to the configuration connected in module units, and can be connected in cluster units, for example.

  In this modification, the output converters T11 to T13 are connected to the clusters CLS11 to CLS13. However, the present invention is not limited to this, and the output converters T11 to T13 may be connected to each cell.

  That is, the output converters T11 to T13 can be connected to the solar cell to suppress the DCDC conversion loss, and to obtain the maximum output power after the DCDC conversion that cannot be obtained simply by maximizing the output of the solar cell. There is an effect that it can be obtained.

  Note that a solar cell includes a cell that is a photovoltaic power generation element, a cluster or module in which a plurality of cells are connected in series, a string in which modules are connected in series, and an array in which strings are connected in parallel. It is a waste.

[Embodiment 2]
Another embodiment of the present invention is described below with reference to FIG. This embodiment demonstrates the case where various sensors are provided in a solar power generation system, and a control management apparatus controls the output converter in a solar power generation system based on the measurement result of a sensor.

(About the configuration of the photovoltaic power generation system)
First, the schematic configuration of the photovoltaic power generation system 2 according to the present embodiment will be described with reference to FIG. For convenience of explanation, members having the same functions as those in the drawings described in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  The photovoltaic power generation system 2 includes modules MOD11, MOD12, MOD13, output converters T21, T22, T23, a power conditioner 60, and a control management device 61.

  Note that FIG. 9 does not clearly indicate whether the modules MOD11, MOD12, MOD13,... Belong to one array or one string, but are designed as belonging to the same or different arrays / strings as appropriate. Needless to say, changes are possible.

  The output converters T21, T22, T23... Are connected to the modules MOD11, MOD12, MOD13... As an example, but the present invention is not limited to this. Is possible.

  The difference between the photovoltaic power generation system 2 shown in FIG. 9 and the photovoltaic power generation system 1 shown in FIG. 2 is that the photovoltaic power generation system 2 shown in FIG. 9 further includes a control management device 61. The power conditioner 60 includes a power measuring unit 65, and each of the output converters T11 to T13 further includes a control content determining unit (voltage determining unit, detour determining unit, short-circuit determining unit, receiving unit) 70. It is a point that has.

  Moreover, in the photovoltaic power generation system 2, the control management device 61 and the output converters T21, T22, T23... Are connected by a communication network. One-way communication is realized for the output converters T21, T22, T23. Further, the control management device 61 and the power conditioner 60 are also connected by a communication network, and at least communication from the power conditioner 60 to the control management device 61 is realized.

  In FIG. 9, the connection relationship of the power lines and the description of the load are omitted.

(Details of differences)
Hereinafter, the control content determination unit 70 included in each of the control management device 61 and the output converters T21, T22, T23... Will be described in detail with reference to FIG.

  First, the electric power measurement part 65 with which the power conditioner 60 is provided is demonstrated.

  The power measurement unit 65 measures the power output from the entire array connected to the power conditioner 60 or the entire string, and generates power data (array output power data).

  Next, the control management device 61 will be described. The control management device 61 includes a control data acquisition unit 62 and a control data transmission unit 63.

  The control data acquisition unit 62 acquires data for the output converters T21, T22, T23... To determine control contents. The control data acquisition unit 62 acquires power data from the power measurement unit 65.

  The control data acquisition unit 62 is connected to a measurement unit 64 including various measurement sensors, and receives various measurement data from the measurement unit 64.

  The measurement unit 64 typically includes a thermometer 64A and a pyranometer 64B. The thermometer 64A is for measuring the outside air temperature, and is installed in a place not exposed to direct sunlight around the solar cell array. The solar radiation meter 64B is installed in the solar cell array at the same inclination angle as the solar cell array in order to measure the solar radiation intensity applied to the solar cell.

  The control data acquisition unit 62 acquires power data from the power measurement unit 65, temperature data and solar radiation intensity data from the measurement unit 64, and transfers the acquired data to the control data transmission unit 63.

  The control data transmission unit 63 sends the temperature data, solar radiation intensity data, and power data transferred from the control data acquisition unit 62 as control data to the control content determination unit 70 included in each of the output converters T21, T22, T23. To be sent.

  Subsequently, the configuration of the output converters T21, T22, T23... Will be described by taking the output converter T21 as an example. Since the configurations of the output converters T22 and T23 are the same as the configuration of the output converter T21 shown below, the description thereof is omitted.

  The control content determination unit 70 included in the output converter T21 receives various types of control data such as temperature data, solar radiation intensity data, and power data from the control data acquisition unit 62, and performs maximum processing based on the received various types of control data. This is for determining the control content of the operating point control unit 54.

  For example, the maximum operating point control unit 54 determines whether or not an instruction to perform DCDC conversion is given from the control content determination unit 70 in the process of S15 of the flowchart shown in FIG. As a result, if DCDC conversion is instructed, the DCDC converter 53 may be controlled to perform DCDC conversion.

  How the control content determination unit 70 uses the control data to determine the control content will be specifically described below.

[How to use temperature data]
The control content determination unit 70 determines the control content of the maximum operating point control unit 54 by using the temperature data as follows.

  As a premise, in the output converter T22, the temperature and the output voltage of the module MOD11 assumed under the temperature are associated with each other and stored in a storage unit (not shown).

  Then, the control content determination unit 70 reads the output voltage of the module MOD11 corresponding to the temperature indicated by the received temperature data from the storage unit, and compares it with the output voltage actually obtained from the module MOD11.

  As a result of the comparison, if the output voltage obtained from the module MOD11 is smaller than expected, the temperature of the module MOD11 is higher than that around the control management device 61, and the output voltage is likely to be reduced.

  In this case, the control content determination unit 70 determines to perform DCDC conversion control by the DCDC conversion unit 53 and instructs the maximum operating point control unit 54 to perform control with the determined control content.

[How to use sunshine intensity data]
The control content determination unit 70 determines the control content of the maximum operating point control unit 54 by using the sunshine intensity data as follows.

  As a premise, in the output converter T21, the reference value of the sunshine intensity that can be determined to obtain a good solar radiation intensity and the output power of the module MOD11 that is assumed when a good solar radiation intensity is obtained are stored. deep.

  Then, the control content determination unit 70 compares the received solar radiation intensity data with the stored reference value of the solar radiation intensity to determine whether or not a good solar radiation intensity is obtained.

  If it can be determined that good solar radiation intensity is obtained, there is no shadow around the control management device 61, and the solar power generation system 2 as a whole has good solar radiation intensity.

  In this case, the output power of the module MOD11 assumed when a good solar radiation intensity is obtained is compared with the output power actually obtained from the module MOD11.

  As a result of the comparison, if the output power obtained from the module MOD11 is smaller than expected, it can be determined that there is a high possibility that the module MOD11 is shaded and the output power is decreasing.

  In this case, the control content determination unit 70 determines to perform DCDC conversion control by the DCDC conversion unit 53 and instructs the maximum operating point control unit 54 to perform control with the determined control content.

[How to use power data]
The control content determination unit 70 determines the control content of the maximum operating point control unit 54 by using the power data as follows.

  The control content determination unit 70 uses the power data to calculate how much of the output power of the entire array is occupied by the output power of the output converter T21 itself.

  When the calculated ratio is smaller than the assumed ratio, the output converter T21 can output only a small amount of power compared to the other output converters T22, T23.

  In this case, the control content determination unit 70 determines to perform DCDC conversion control by the DCDC conversion unit 53 and instructs the maximum operating point control unit 54 to perform control with the determined control content.

(Modification)
In the above, various control data is transmitted from the control data transmission unit 63 to the control content determination unit 70, and the control content determination unit 70 determines the control content in the output converter T21 from the received various control data. Explained.

  However, the configuration is not limited to the above, and the following configuration is also possible.

  That is, the control content in the output converter T21 may be determined in the control management device 61, and the output converter T21 may perform control according to the control content determined by the control management device 61.

  Specifically, the control management device 61 may determine the control content of the output converter T21 based on various control data acquired by the control data acquisition unit 62.

  Further, the control data transmitted from the control data transmission unit 63 may be a set of current data and voltage data.

  Further, the total power data may be calculated in array units, or may be calculated from any unit of string units, module units, and cluster units.

  In the above description, the control management device 61 and the power conditioner 60 are configured separately, but the power conditioner 60 may be configured to include the control management device 61. In addition, when the control management device 61 is built in the power conditioner 60, the wiring for communication and the wiring for power can be used in common, so that the amount of wiring is reduced and the circuit is simplified. Can do.

[Embodiment 3]
Another embodiment of the present invention will be described as follows. In this embodiment, in the photovoltaic power generation system 2 shown in FIG. 9, various sensors are further provided on the module side, and control management is performed based on the measurement results of the measurement units connected to the module side and the control management device. The case where an apparatus controls the output converter in a solar power generation system is demonstrated.

(About the configuration of the photovoltaic power generation system)
First, the schematic configuration of the photovoltaic power generation system 3 according to the present embodiment will be described with reference to FIG. For convenience of explanation, members having the same functions as those in the drawings described in the first and second embodiments are denoted by the same reference numerals and description thereof is omitted.

  The solar power generation system 3 includes modules MOD11, MOD12, MOD13, output converters (voltage setting devices) T31, T32, T33, a power conditioner 60, and a control management device 80.

  It is arbitrary whether the modules MOD11, MOD12, MOD13,... Belong to the same or different arrays / strings.

  The difference between the photovoltaic power generation system 3 shown in FIG. 10 and the photovoltaic power generation system 2 shown in FIG. 9 is as follows. That is, in the photovoltaic power generation system 3 shown in FIG. 10, the control management device 80 includes a control data receiving unit (power data receiving unit) 81 and a control content determining unit (voltage determining unit, detour determining unit, short circuit determining unit) 82. And a control instruction section (control data transmission means) 83, and output converters T31, T32, T33,... Are each provided with a control data acquisition section (output power detection means, power measurement means) 71, control. The data transmission unit (transmission means) 72 and the output adjustment unit 73 are provided.

  Further, in the photovoltaic power generation system 3, the control management device 80 and the output converters T31, T32, T33,... Are connected by a network capable of bidirectional communication, whereby the power conditioner 60, the module MOD11, MOD12, MOD13, etc. can communicate with each other. The control management device 80 is connected to the power conditioner 60 via a communication network. In addition, in FIG. 10, the connection relation of the power line and the description of the load are omitted.

(Details of differences)
Hereinafter, the control data acquisition unit 71, the control data transmission unit 72, the output adjustment unit 73, and the control management device 80 included in each of the output converters T31, T32, T33... Will be described with reference to FIG.

  First, of the output converters T31, T32, T33..., The control data acquisition unit 71 and the control data transmission unit 72 will be described with the output converter T31 as an example. It is assumed that each of the output converters T31, T32, T33... Is connected to a measurement unit (not shown) including a thermometer and a pyranometer. This measurement part is provided in the vicinity of the module, for example, and measures the temperature and solar radiation intensity near the module.

  The control data acquisition unit 71 acquires various control data and transfers the acquired data to the control data transmission unit 72.

  Examples of data acquired by the control data acquisition unit 71 include temperature data and solar radiation intensity data acquired from the measurement unit. Further, in the output converter T31, power is obtained based on the voltage / current measured by the primary side voltage / current monitoring unit 55 and the secondary side voltage / current monitoring unit, and the obtained primary side / secondary side power is obtained as power. The data acquisition part 71 for control may acquire as data.

  In addition, as the control data acquired by the control data acquisition unit 71, the input current / input voltage of the primary side S1, the output current / output voltage of the secondary side S2, the on / off state of the DCDC short-circuit switch 51 are included. The state, the ON / OFF state of the module short-circuit switch 52, the Duty value at the time of DCDC conversion, and the like can be given.

  The control data transmission unit 72 controls communication of the control management device 80, and the control data reception unit 81 provided in the control management device 80 includes various control data transferred from the control data acquisition unit 71. To send to.

  The output adjustment unit 73 controls communication with the control management device 80, receives the control content transmitted from the control instruction unit 83, and controls the output converter T31 based on the received control content. Is for. Thus, since the output converter T31 includes the output adjustment unit 73, the maximum operating point control unit 54 shown in FIG. 1 is not provided. Unlike the maximum operating point control unit 54, the output adjustment unit 73 does not perform the control content determination. Therefore, in the output converter T31, since the block for determining the control content is not essential, the circuit can be simplified correspondingly.

  That is, the control management device 80 may control all of the output converters T31, T32, T33.

  Next, the control management device 80 will be described.

  The control data receiving unit 81 is for receiving various control data transmitted from the control data transmitting unit 72.

  The control content determination unit 82 collects the various control data acquired by the control data acquisition unit 62 and the various control data received by the control data reception unit 81, and based on the collected various control data, Control contents to be executed in the output converters T31, T32, T33... Are determined. The control content determination unit 82 transfers the determined control content to the control instruction unit 83.

  The control instruction unit 83 transmits the control content transferred from the control content determination unit 82 to the output converters T31, T32, T33,... Connected via the communication network.

(Operation details of the control content determination unit)
Next, how the control content determination unit 82 uses the control data to determine the control content will be specifically described below.

  The control content determination unit 82 determines the control content as follows using the control data collected from the control data transmission unit 72 included in the output converters T31, T32, T33. The control content determination unit 82 collects control data.

  First, the control content determination unit 82 determines whether there is a module whose output is estimated to be reduced among the modules constituting the string.

  For example, if the control content determination unit 82 determines from the temperature data that there is a module whose temperature is extremely high compared to other modules, the control content determination unit 82 determines the control content for performing control to turn on the module short-circuit switch. To do. Then, the control instruction unit 83 instructs the output converter to which the module is connected to perform control based on the control content.

  In addition, it is determined from the output current / output voltage of the secondary side S2 and the solar radiation intensity whether there is any module in which the output is reduced.

  When it is determined that DCDC conversion is preferable based on the estimated output based on various control data collected from the output converter T11, the control content determination unit 82 determines the control content for performing DCDC control. To do.

  When it is determined that it is preferable to turn on the DCDC short-circuit switch 51 from the estimated output based on various control data collected from the output converter T11, the control content determination unit 82 sets the DCDC short-circuit switch 51 to The control content for performing the control to turn on is determined.

  The control content determined by the control content determination unit 82 is transmitted to the output converter T11 by the control instruction unit 83.

(Modification)
In the above, the control content determination unit 82 collects the various control data acquired by the control data acquisition unit 62 and the various control data received by the control data reception unit 81, and the collected various control data Based on this, the determination of the control contents to be executed in the output converters T31, T32, T33.

  However, the present invention is not limited to this, and like the control management device 61 described with reference to FIG. 9, the control data acquired and collected in the control management device 80 is transmitted to the output converters T31, T32, T33. In the output converters T31, T32, T33,..., The control content can be determined based on the received control data.

  Further, a database for recording various control data acquired by the control data acquisition unit 62 and various control data received by the control data receiving unit 81 is provided in the control management device 80 and collected in the control management device 80. The history of the control data may be managed.

  For example, if the transmission source output converter of the collected control data, the collected time, and the control data are recorded in association with each other, for each module, one year unit, one season unit, one month unit It is possible to grasp the power generation tendency for each week or for each time zone.

  Therefore, the control management device 80 can instruct the output converter connected to the module that is known to be shaded in a predetermined time zone to perform control to turn on the module short-circuit switch. it can. In addition, for an output converter connected to a module that is known to have sufficient solar radiation intensity in a predetermined time zone, the control management device 80 controls to turn on the DCDC short-circuit switch. Can be instructed to do.

  The invention according to this embodiment can also be expressed as follows.

  In the control management device, the voltage setting device further includes a bypass circuit for bypassing the voltage change circuit and outputting the current output from the solar cell to the outside, and the voltage is output from the solar cell. The circuit further comprises detour determination means for determining whether the current is output to the outside via the voltage change circuit or to the outside via the detour circuit, and the control data transmission means is determined by the detour determination means. The result is transmitted to the voltage setting device.

  The voltage setting device is a voltage setting device that is connected to the control management device via a communication network, sets a voltage for the current output from the solar cell, and outputs the voltage to the outside. A voltage change circuit configured to be changeable, output power detection means for detecting power output from the voltage change circuit, and transmission for transmitting output power detected by the output power detection means to the control management device Means, a bypass circuit for bypassing the voltage change circuit and outputting the current output from the solar cell to the outside, and a receiving means for receiving the control data transmitted from the control management device. It is characterized by providing.

  In addition, the invention according to the present embodiment can also be expressed as follows.

  The voltage setting device determines the voltage of the voltage setting device so that the received output power is maximized, and detects the output power via a communication network to a control management device that transmits the determined voltage as voltage data. Transmission means for transmitting output power detected by the means, and reception means for receiving the voltage data transmitted from the control management device, wherein the voltage determination means changes the voltage based on the received voltage data. The voltage set by the circuit is determined.

  The control management device sets a voltage with respect to the current output from the solar cell, outputs the voltage to the outside, and outputs a voltage change circuit capable of changing the voltage, and electric power output from the voltage change circuit. A control management device connected via a communication network to a voltage setting device having an output power detection means for detecting, the power receiving the output power detected by the output power detection means from the voltage setting device Data receiving means; voltage determining means for determining the voltage of the voltage setting device so that the output power indicated by the power data received by the power data receiving means is maximized; and the voltage determined by the voltage determining means Control data transmission means for transmitting to the voltage setting device.

  According to the above configuration, the voltage setting device outputs a current to the outside via the bypass circuit according to the control data transmitted from the control management device.

  As a result, in the voltage setting circuit, it is possible to output a current to the outside via a bypass circuit as necessary, thereby producing an effect that power loss can be suppressed.

  In addition, the invention according to the present embodiment can also be expressed as follows.

  In the control management device, the voltage setting device includes a power measuring means for measuring the power output from the solar cell between the solar cell and the voltage changing circuit or the bypass circuit, and a voltage to the outside. A short-circuit switching circuit that switches between two short-circuited states and a non-short-circuited state between two output terminals that output a short-circuit determining means for controlling a switching operation of the short-circuit switching circuit; The short-circuit determining means controls the short-circuit switching circuit to be in the short-circuited state when the power measured by the power measuring means satisfies a predetermined standard, and the control data transmitting means The control result by the short-circuit determining means is transmitted to the voltage setting device.

  The voltage setting device is a voltage setting device that is connected to the control management device via a communication network, sets a voltage for the current output from the solar cell, and outputs the voltage to the outside. Between the voltage change circuit configured to be changeable, output power detection means for detecting the power output from the voltage change circuit, the solar battery, and the solar battery between the voltage change circuit or the bypass circuit A power measuring means for measuring the power output from the power supply, a short-circuit switching circuit for switching between a short-circuited state and a non-short-circuited state between two output terminals that output a voltage to the outside, and the output power Transmitting means for transmitting the output power detected by the detecting means and the power measured by the power measuring means to the control management apparatus; Receiving means for receiving the control data, characterized in that it comprises a.

  According to the said structure, according to the control data transmitted from a control management apparatus, a voltage setting apparatus will be in the state which short-circuited the short circuit switching circuit.

  As a result, in the voltage setting device, it is possible to output a voltage from one output terminal to the other output terminal via two output terminals that are short-circuited as necessary.

[Embodiment 4]
Another embodiment of the present invention is described below with reference to FIG. In this embodiment, in the photovoltaic power generation system, a server for monitoring and recording the state of the power generation system including the power conditioner 22 and the array ARRA is provided so that the power generation amount trend analysis and state management can be performed. is there.

(About the configuration of the photovoltaic power generation system)
The schematic configuration of the photovoltaic power generation system 4 according to the present embodiment will be described with reference to FIG. For convenience of explanation, members having the same functions as those in the drawings described in the first and second embodiments are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIG. 11, the photovoltaic power generation system 4 includes a plurality of arrays ARRA, a power conditioner 22, a server 90, and a display unit 93.

  The array ARRA includes a plurality of strings STR101 to STRX. The string STR101 includes a plurality of sets each including a module and an output converter connected to the module. The output converters TA1 to TAn are connected in series. The same applies to the other strings.

  Each of the output converters TA1 to TAn has the same configuration as the output converters T31, T32, T33... Described with reference to FIG.

  The power conditioner 22 includes a control management device 23 and an inverter 21.

  The server 90 includes a state monitoring device 91 and a storage unit 92, and is connected to the display unit 93.

  The state monitoring device 91 is connected to the power conditioner 22 through a communication network, acquires control data transmitted from each output converter via the control management device 23, and stores it in the storage unit 92. It is. The state monitoring device 91 stores the acquired control data in the storage unit 92 in association with the acquisition source module, string, and array, and the acquired time zone.

  Then, the state monitoring device 91 displays the content stored in the storage unit 92 on the display unit 93 in real time. On the other hand, according to a request from the display unit 93, the contents of past control data and the statistical value of the control data can be displayed.

  The state monitoring device 91 may be connected to a plurality of power conditioners 22.

  According to such a configuration of the photovoltaic power generation system 4, an administrator of the photovoltaic power generation system 4 can refer to control data and statistical data stored in the storage unit 92. The state of the power generation system 4 can be easily grasped, and the power generation tendency can be confirmed.

(Summary)
The present invention is suitably applicable to residential and industrial solar cell modules. However, the present invention is not limited to this, and the present invention can be applied to a small-scale solar battery device. In this case, since the output voltage / output current is small, the output converter can be downsized.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.

  The present invention is widely applicable to solar power generation systems regardless of the scale.

1, 2, 3, 4 Photovoltaic power generation system 30 Load 51 DCDC short-circuit switch (bypass circuit)
52 Module short circuit switch (short circuit switching circuit)
53 DCDC converter (voltage change circuit)
54 Maximum operating point controller (voltage determining means, detour determining means, short circuit determining means)
55 Primary voltage / current monitoring unit (electric power measurement means)
56 Secondary side voltage / current monitor (output power detection means)
60 power conditioner 61 control management device 62 control data acquisition unit 63 control data transmission unit 70 control content determination unit (voltage determination unit, detour determination unit, short-circuit determination unit, reception unit)
71 Control data acquisition unit (output power detection means, power measurement means)
72 Control Data Transmitter (Transmitter)
73 Output adjustment unit (reception means)
80 control management device 81 control data receiving unit (power data receiving means)
82 Control content determination unit (voltage determination means, detour determination means, short circuit determination means)
83 Control instruction section (control data transmission means)
ARR11 Array CLS11 to CLS13 Cluster (solar cell)
MOD11 to MOD13 modules (solar cells)
MOD21 Module STR11 String T11 to T13 Output converter (voltage setting device)
T21, T22, T23 ... Output converter (voltage setting device)
T31, T32, T33 ... Output converter (voltage setting device)

Claims (12)

In the voltage setting device that sets the voltage for the current output from the solar cell and outputs the voltage to the outside,
A voltage changing circuit capable of changing the voltage;
Output power detection means for detecting power output from the voltage changing circuit;
And a voltage determining unit that determines a voltage set by the voltage changing circuit so that the output power detected by the output power detecting unit is maximized. A power measuring means for measuring the power output from the solar cell between the solar cell and the voltage changing circuit;
After the voltage determining means determines the temporary voltage set by the voltage changing circuit so that the power measured by the power measuring means is maximized, the output power detecting means detects the temporary voltage based on the temporary voltage. The voltage setting device according to claim 1, wherein the voltage set by the voltage changing circuit is determined so that output power to be maximized. A detour circuit for bypassing the voltage change circuit and outputting the current output from the solar cell to the outside;
The circuit further comprises detour determining means for determining whether the current output from the solar cell is output to the outside via the voltage change circuit or to the outside via the detour circuit. The voltage setting device according to claim 1.   The detour determination means determines whether to output to the outside via the voltage change circuit or to the outside via the detour circuit based on at least one of temperature and solar radiation intensity in the solar cell. The voltage setting device according to claim 3, wherein: A power measuring means for measuring the power output from the solar battery between the solar battery and the voltage changing circuit or the bypass circuit;
The detour determination unit determines whether to output to the outside via the voltage change circuit or to the outside via the detour circuit based on the power measured by the power measurement unit. The voltage setting device according to claim 3. Power measuring means for measuring the power output from the solar cell between the solar cell and the voltage changing circuit or the bypass circuit;
A short-circuit switching circuit that switches between two output terminals that output a voltage to the outside between a short-circuited state and a non-short-circuited state;
Short-circuit determining means for determining whether to switch the short-circuit switching circuit to a short-circuited state,
4. The voltage according to claim 3, wherein the short-circuit determining unit determines to switch the short-circuit switching circuit to the short-circuited state when the power measured by the power measuring unit is equal to or less than a predetermined value. Setting device. Receiving means for receiving array output power data indicating the output power of the solar cell array via a communication network;
4. The detour determination means determines whether to output to the outside via the voltage change circuit or to the outside via the detour circuit based on the array output power data. The voltage setting device described in 1. Receiving means for receiving array output power data indicating the output power of the solar cell array via a communication network;
The short-circuit determining means determines whether or not the power measured by the power measuring means satisfies a predetermined standard based on the ratio of the power measured by the power measuring means and the power indicated by the array output power data. The voltage setting device according to claim 6.   The voltage setting device according to any one of claims 1 to 6, further comprising transmission means for transmitting power data indicating output power detected by the output power detection means. Power data receiving means for receiving power data;
Voltage determining means for determining the voltage so that the output power indicated by the power data received by the power data receiving means is maximized;
And a control data transmitting means for transmitting the voltage determined by the voltage determining means.   A photovoltaic power generation system comprising the voltage setting device according to claim 9 and the control management device according to claim 10. In the control method of the voltage setting device that sets the voltage for the current output from the solar cell and outputs the voltage to the outside,
An output power detection step for detecting power output from a voltage change circuit capable of changing the voltage;
And a voltage determining step for determining a voltage set by the voltage changing circuit so that the output power detected in the output power detecting step is maximized.

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