JP2012129469A - Device for controlling photovoltaic power generation facility - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for controlling a photovoltaic power generation facility, which can efficiently operate at maximum power even if a plurality of maximum values are generated in output power under the influence of clouds.SOLUTION: An output determination section 24 compares a main array output Pm controlled by a main MPPT controller 19 or a wide-sweeping output Pw controlled by a wide-sweeping controller 22 and N times of a pilot output Pp controlled by a pilot MPPT controller 21, and determines whether the main array output Pm or the wide-sweeping output Pw is N times of the pilot output Pp or more. An operation selection switching section 23 selects operation by the main MPPT controller 19 when the output determination section 24 determines that the main array output Pm or the wide-sweeping output Pw is N times of the pilot output Pp or more. When the output determination section 24 determines that the main array output Pm or the wide-sweeping output Pw is lower than N times of the pilot output Pw, the operation selection switching section 23 selects operation by the wide-sweeping controller 22.

Description

  The present invention relates to a control device for a photovoltaic power generation facility provided with an array composed of a plurality of solar cell modules.

  In general, a photovoltaic power generation facility forms solar cell modules by connecting solar cells that photoelectrically convert sunlight into solar cells, converts DC power generated by the solar cell modules into AC power using an inverter, and an electric power system. And AC power is supplied to the power system.

  Solar cells have different operating points that generate maximum power depending on solar radiation intensity and temperature. Therefore, in order to effectively use the power generated by solar cells, follow the optimal operating point at which the maximum power that changes every moment can be extracted. It is important to generate electricity.

  In order to obtain the optimum operating point, maximum power tracking control {MPPT (Maximum Power Point Tracking) control} for tracking control to the optimum operating point at which the output of the solar battery cell becomes maximum is used. For example, the output power obtained at the current operating point is compared with the output power obtained at the operating point slightly moved from the current operating point to determine the direction to the optimal operating point, and to the optimal operating point. The hill-climbing method to follow is used. Thus, the photovoltaic power generation facility is equipped with a maximum power point tracking (MPPT) control function.

  In the case of a large-scale photovoltaic power generation system in which solar cells are connected in series to form a solar cell module, and this solar cell module is connected in series to form a main array, a part of the solar cell module is affected by clouds. And the output characteristic curve (power P-voltage V curve) may have a plurality of peaks (maximum values) when viewed as the main array as a whole, and the true maximum power point cannot be detected by the hill-climbing method. Sometimes.

  Therefore, even if the solar radiation changes and a part of the panel is shaded and multiple maximum values occur in the output power of the solar cell, the maximum power maximum value is not affected by the occurrence of multiple maximum values. There is one that can follow and control the output power value from the solar cell at a substantially maximum value (see, for example, Patent Document 1).

  In addition, a pilot cell whose output characteristics are similar to that of the photovoltaic power generation facility is provided, and the operating voltage of the pilot cell when the output is maximized by changing the load state of the pilot cell is obtained. From this, the input power command value of the power converter Is derived (see, for example, Patent Document 2).

JP 2006-59126 A Japanese Patent Laid-Open No. 62-15617

  However, the one of Patent Document 1 includes a GA controller that regards a set value as a gene and uses an output power value from a solar cell as a gene evaluation value, and performs genetic algorithm processing. It becomes complicated.

  Moreover, since the thing of the patent document 2 always changes the load state of a pilot cell and calculates | requires the operating voltage of a pilot cell when an output becomes the maximum, the driving | operation of a pilot cell is the optimal operation that the output becomes the maximum It is not possible to continue driving at the point. Therefore, the pilot cell output constantly fluctuates, resulting in inefficient operation.

  An object of the present invention is to provide a control device for a photovoltaic power generation facility that can be efficiently operated at the maximum output even when a plurality of local maximum values are generated in the output power due to the influence of clouds.

  The control device for a photovoltaic power generation facility according to the invention of claim 1 is a solar power generation facility having a main array composed of N main modules having the same output characteristics and a pilot module having the same output characteristics as the main modules. In the control device, a main MPPT control unit that performs maximum power tracking control of the main array at a predetermined period and outputs a voltage command determined by the maximum power tracking control to a main inverter, and the pilot module in synchronization with the main MPPT control unit A pilot MPPT control unit that outputs a voltage command determined by the maximum power tracking control to the pilot inverter, and moves the operating voltage of the main array within a predetermined voltage search range to increase the maximum output operating voltage. The main output is searched using the maximum output operating voltage searched for as a voltage command. A wide sweep control unit that sets the searched maximum output operating voltage as a voltage command of the main MPPT control unit, and a main array output controlled by the voltage command of the main MPPT control unit or the wide sweep The wide sweep output controlled by the voltage command of the control unit is compared with N times the pilot output controlled by the voltage command of the pilot MPPT control unit, and the main array output or the wide sweep output is N of the pilot output. An output determination unit for determining whether or not the output is greater than or equal to a multiple, and the main MPPT control unit when the output determination unit determines that the main array output or the wide sweep output is N or more times the pilot output The main output or wide sweep output is selected by the output judgment unit. There when it is determined to be less than N times the pilot output is characterized in that a driver selection switch unit for selecting operation of the wide sweep controller.

  According to a second aspect of the present invention, there is provided a control device for a photovoltaic power generation facility, wherein, in the first aspect of the invention, it is determined whether or not the number of times of operation selection by the wide sweep control unit has continuously exceeded a predetermined number of times. When this is the case, a driving selection monitoring unit that notifies the driving selection switching unit to that effect is provided, and the driving selection switching unit continuously counts the number of driving selections by the wide sweep control unit from the driving selection monitoring unit. When the notification that the predetermined number of times has been reached is received, the selection of the operation of the wide sweep control unit thereafter is prohibited, and the operation of the main MPPT control unit is continued.

  According to a third aspect of the present invention, there is provided a control device for a photovoltaic power generation facility according to the second aspect, wherein the operation selection monitoring unit continuously performs the number of operation selections by the wide sweep control unit in addition to the operation selection switching unit. The output determination unit also notifies the output determination unit that the predetermined number of times has been reached, and the output determination unit has continuously exceeded the predetermined number of times of operation selection by the wide sweep control unit from the operation selection monitoring unit. Is obtained as an offset value by adding a margin value to the absolute value of the difference between the main array output at the predetermined number of times and N times the pilot output, and thereafter the main array output is obtained. It is determined whether or not a value obtained by adding an offset value to the output or wide sweep output is N times or more of the pilot output.

  According to a fourth aspect of the present invention, there is provided the control apparatus for photovoltaic power generation equipment according to the third aspect, wherein the offset value is an absolute value of a difference between the main array output and N times the pilot output at a predetermined number of times. In place of the value obtained by adding the margin value to the margin value, the margin value is set to the average value or minimum value of the absolute value of the difference between the main array output and N times the pilot output at each selection of operation by the wide sweep control unit. It is characterized by the added value.

  According to a fifth aspect of the present invention, there is provided the control apparatus for photovoltaic power generation equipment according to the third aspect, wherein the offset value is an absolute value of a difference between the main array output and N times the pilot output at a predetermined number of times. Instead of a value obtained by adding a margin value to the main MPPT control unit, the main MPPT control unit has a maximum power follow-up control whose fluctuation of the main array output is smaller than a predetermined fluctuation value and any time within a predetermined period after noon The value obtained by adding a margin value to the absolute value of the difference between the main array output at N and the N times the pilot output.

  According to the invention of claim 1, when the main array output is N times or more of the pilot output, the operation of the main MPPT control unit is continued, and when the main array output becomes less than N times the pilot output, the wide output Since the maximum output operating voltage is searched in a predetermined wide voltage range by the operation of the sweep control unit, and the searched maximum output operating voltage is set as the voltage command of the main MPPT control unit, the main array is affected by the cloud. Thus, even when the main array output characteristic becomes an output characteristic having a plurality of maximum values, it is possible to efficiently operate at the maximum output.

  According to the second aspect of the present invention, when the number of times of switching by the wide sweep control unit is continuously equal to or greater than the predetermined number of times, the subsequent switching to the wide sweep control unit is prohibited. When the output of the main array is small due to a failure of some main modules constituting the array, it is possible to prevent operation by an unnecessary wide sweep control unit.

  According to the third aspect of the present invention, when the number of switching operations by the wide sweep control unit continuously exceeds a predetermined number, the difference between the main array output at the predetermined number of times and N times the pilot output is calculated. The value obtained by adding the margin value to the absolute value is obtained as an offset value, and thereafter, it is determined whether the value obtained by adding the offset value to the main array output is N times or more of the pilot output. If the output of the main array is small due to a failure of some of the main modules that make up the main array, the maximum output operating voltage can be increased even if the main array output characteristics are output characteristics having a plurality of maximum values. You can search and operate efficiently with maximum output.

  According to the invention of claim 4, the offset value adds a margin value to the average value or the minimum value of the absolute value of the difference between the main array output and N times the pilot output every time the operation is switched by the wide sweep control unit. Therefore, it can be a value close to the output drop of the failed main module.

  According to the invention of claim 5, when the operation switching to the wide sweep control unit is prohibited and the operation of the main MPPT control unit is continued, the main array output is performed by the maximum power follow-up control in the main MPPT control unit. A value obtained by adding a margin value to the absolute value of the difference between the main array output and N times the pilot output at any point in time within a predetermined period after noon. Since the offset value is obtained, the offset value can be made closer to the output drop of the failed main module.

The block diagram of the control apparatus of the solar power generation facility which concerns on the 1st Embodiment of this invention. The time chart which shows operation | movement of the control apparatus of the solar power generation facility which concerns on the 1st Embodiment of this invention The block diagram of the control apparatus of the solar power generation facility which concerns on the 2nd Embodiment of this invention. The block diagram of the control apparatus of the solar power generation facility which concerns on the 3rd Embodiment of this invention.

  Embodiments of the present invention will be described below. FIG. 1 is a configuration diagram of a control device for a photovoltaic power generation facility according to the first embodiment of the present invention. The photovoltaic power generation facility includes a main array 11 and a pilot module 12. The main array 11 is configured by connecting N main modules 13a to 13n having the same output characteristics in series. The main modules 13a to 13n are solar cell modules, and the solar cell module includes a plurality of solar cells not shown. It is formed by connecting battery cells in series. The pilot module 12 is formed of a solar cell module having the same output characteristics as the main modules 13a to 13n.

  The DC power generated by the main array 11 is converted into AC power by the main inverter 14 and output to the AC system 15. Similarly, DC power generated by the pilot module 12 is converted to AC power by the pilot inverter 16 and output to the AC system 15.

  The operating current Im of the main array 11 is detected by the current detector 17m, and the operating voltage Vm of the main array 11 is detected by the voltage detector 18m and input to the main MPPT control unit 19. The main MPPT control unit 19 performs maximum power tracking control of the main array 11 based on the operating current Im and the operating voltage Vm of the main array 11. For example, the output power Pi obtained at the current operating point and the output power Pi + 1 obtained at the operating point slightly moved from the current operating point are compared to determine the direction to the optimum operating point, and the optimum A hill-climbing method that follows the operating point is used.

  That is, the main MPPT control unit 19 has a VI characteristic between the output voltage V and the output current I of the main array 11 and a VP characteristic between the output voltage V and the output power P of the main array 11 that change depending on the solar radiation intensity. Then, the operating voltage Vm is changed to obtain the maximum operating voltage, and the obtained maximum output operating voltage of the main array 11 is output to the main inverter 14 via the changeover switch 20 as the voltage command sm.

  On the other hand, the operating current Ip of the pilot module 12 is detected by the current detector 17p, and the operating voltage Vp of the pilot module 12 is detected by the voltage detector 18p and input to the pilot MPPT control unit 21. Similarly to the main MPPT control unit 19, the pilot MPPT control unit 21 also performs maximum power tracking control of the pilot module 12 based on the operating current Ip and the operating voltage Vp of the pilot module 12. The maximum output operating voltage of the pilot module 12 is output to the pilot inverter 16 as a voltage command sp.

  Next, the wide sweep control unit 22 receives the operating current Im and the operating voltage Vm of the main array 11, and moves the operating voltage Vm of the main array 11 within a predetermined voltage search range to search for the maximum output operating voltage. The detected maximum output operating voltage is output to the main inverter 14 via the changeover switch 20 as a voltage command sw. At the same time, the searched maximum output operating voltage is set as the voltage command Vw of the main MPPT control unit 19.

  The changeover switch 20 switches between the voltage command sm that is the output of the main MPPT control unit 19 and the voltage command sw that is the output of the wide sweep control unit 22, and is switched by the operation selection switching unit 23. The operation selection switching unit 23 switches the changeover switch 20 based on the determination result of the output determination unit 24.

  The output determination unit 24 includes a main array output Pm controlled by the voltage command sm of the main MPPT control unit 19 or a wide sweep output Pw controlled by the voltage command sw of the wide sweep control unit 22 and the voltage of the pilot MPPT control unit 21. The pilot output Pp controlled by the command sp is compared with N times to determine whether the main array output Pm or the wide sweep output Pw is N times or more of the pilot output Pp. That is, it is determined whether Pm ≧ Pp × N (or Pw ≧ Pp × N) is established, and the determination result is output to the operation selection switching unit 23.

  When the output determination unit 24 determines that the main array output Pm or the wide sweep output Pw is N times or more the pilot output Pp, the operation selection switching unit 23 connects the changeover switch 20 to the main MPPT control unit 19 side. Then, the operation of the main MPPT control unit 19 is selected. Thus, the voltage command sm from the main MPPT control unit 19 is input to the main inverter 14 and the operation of the main MPPT control unit 19 is continued. On the other hand, when the output determination unit 24 determines that the main array output Pm or the wide sweep output Pw is less than N times the pilot output Pp, the changeover switch 20 is connected to the wide sweep control unit 22 side, and the wide sweep control is performed. The operation permission signal c is output to the unit 22 to switch to the operation of the wide sweep control unit 22. As a result, the operation of the wide sweep control unit 22 is selected, the voltage command sp from the wide sweep control unit 22 is input to the main inverter 14, and the operation at the maximum output operating voltage searched by the wide sweep control unit 22 is performed. Become.

  The synchronization circuit 25 outputs a clock signal that determines the operation timing of the main MPPT control unit 19, the pilot MPPT control unit 21, and the wide sweep control unit 22. Normally, the changeover switch 20 is connected to the main MPPT control unit 19 side. Accordingly, since the main MPPT control unit 19 and the pilot MPPT control unit 21 operate in synchronization, the main array output Pm by the main MPPT control unit 19 input to the output determination unit 24 and the pilot output by the pilot MPPT control unit 21 Pp is data at the same time.

  When the changeover switch 20 is connected to the wide sweep control unit 22 side, the pilot MPPT control unit 21 and the wide sweep control unit 22 operate in synchronization with each other, so that the wide sweep control unit input to the output determination unit 24 The main array output Pm by 22 and the pilot output Pp by the pilot MPPT control unit 21 are data at the same time.

  Next, the operation will be described. FIG. 2 is a time chart showing the operation of the control device for the photovoltaic power generation facility according to the first embodiment. Now, it is assumed that the main MPPT control unit 19 performs the MPPT operation of the main array 11, the pilot MPPT control unit 21 performs the MPPT operation of the pilot module 12, and the wide sweep control unit 22 is stopped.

  As shown in FIG. 2, when there is a clock signal from the synchronization circuit 25 at time t1, the main MPPT control unit 19 and the pilot MPPT control unit 21 operate independently by the clock signal from the synchronization circuit 25. The main MPPT control unit 19 performs MPPT operation on the main array 11, and the pilot MPPT control unit 21 performs MPPT operation on the pilot module 12.

  At time t2 when both the main array power Pm at the maximum output operating voltage by the main MPPT control unit 19 and the pilot power Pp at the maximum output operating voltage by the pilot MPPT control unit 21 are obtained, the output determination unit 24 It is determined whether the main array output Pm is N times or more the pilot output Pp. In this determination, when Pm ≧ Pp × N is satisfied, the current state is maintained. FIG. 2 shows a case where Pm ≧ Pp × N is satisfied at time t2. In this case, since the current state is maintained, when the clock signal from the next synchronization circuit 25 is received, the operation in the main MPPT control unit 19 is continued.

  At time t3, when there is a next clock signal from the synchronization circuit 25, the main MPPT control unit 19 performs MPPT operation of the main array 11 and the pilot MPPT control unit 21 sets the pilot module 12 to MPPT as at time t1. drive. At time t4 when both the main array power Pm in the main MPPT control unit 19 and the pilot power Pp in the pilot MPPT control unit 21 are obtained, the output determination unit 24 determines that the main array output Pm is N of the pilot output Pp. Judge whether it is more than double. FIG. 2 shows a case where Pm ≧ Pp × N is satisfied even at time t4. Also in this case, since the current state is maintained, when the clock signal from the next synchronization circuit 25 is received, the operation in the main MPPT control unit 19 is continued.

  Next, at a time t5 when there is a clock signal from the synchronization circuit 25, similarly, the main MPPT control unit 19 performs the MPPT operation of the main array 11, and the pilot MPPT control unit 21 performs the MPPT operation of the pilot module 12. At time t6 when both the main array power Pm in the main MPPT control unit 19 and the pilot power Pp in the pilot MPPT control unit 21 are obtained, the output determination unit 24 determines that the main array output Pm is N of the pilot output Pp. Judge whether it is more than double.

  At time t6, the case where Pm ≧ Pp × N is not satisfied is shown. Since Pm <Pp × N at time t6, the operation selection switching unit 23 switches the changeover switch 20 from the main MPPT control unit 19 side to the wide sweep control unit 22 side at time t7, and the wide sweep control unit 22 To output an operation permission signal c.

  Then, at time t8 when the clock signal from the synchronization circuit 25 is received, the wide sweep control unit 22 starts to operate with the clock signal. That is, since the wide sweep control unit 22 receives the operation permission signal c from the operation selection switching unit 23, the operation starts when the clock signal from the synchronization circuit 25 is input at time t8. At time t8, not only the pilot MPPT control unit 21 but also the main MPPT control unit 19 operates. However, since the changeover switch 20 is switched to the wide sweep control unit 22 side, the voltage command sm of the main MPPT control unit 19 is the main one. There is no output to the inverter 14.

  The wide sweep control unit 22 searches for the maximum output operating voltage in a predetermined wide voltage range. Therefore, even when the main array is affected by clouds and the main array output characteristic becomes an output characteristic having a plurality of maximum values, the maximum output operating voltage can be obtained. Then, the searched maximum output operating voltage is output to the main inverter 14 as a voltage command. Thereby, even when the main array 11 is affected by clouds and the main array output characteristic becomes an output characteristic having a plurality of maximum values, the main array 11 can be efficiently operated at the maximum output.

  The wide sweep control unit 22 sets the searched maximum output operating voltage as a voltage command for the main MPPT control unit 19. Thus, the voltage command sm of the main MPPT control unit 19 is set to the maximum output operating voltage searched by the wide sweep control unit 22, and the main MPPT control unit 19 can operate the main array 11 at the maximum output operating voltage. Become.

  When both pilot power Pp in pilot MPPT control unit 21 and wide sweep output Pw in wide sweep control unit 22 are obtained at time t9, output determination unit 24 determines that wide sweep output Pw is N times pilot output Pp. It is determined whether it is above. When Pw ≧ Pp × N is satisfied, the operation selection switching unit 23 switches the changeover switch 20 from the wide sweep control unit 22 side to the main MPPT control unit 19 side at time t10. Further, the output of the operation permission signal c to the wide sweep control unit 22 is stopped.

  When the output determination unit 24 does not satisfy Pw ≧ Pp × N, the operation selection switching unit 23 changes the changeover switch 20 from the wide sweep control unit 22 side to the main MPPT control unit 19 side at time t10. Do not switch to. The output of the operation permission signal c to the wide sweep control unit 22 is not stopped.

  Next, when there is a next clock signal from the synchronization circuit 25 at time t11, the changeover switch 20 is switched from the wide sweep control unit 22 side to the main MPPT control unit 19 side at time t10. The MPPT control unit 19 performs MPPT operation on the main array 11, and the pilot MPPT control unit 21 performs MPPT operation on the pilot module 12. At time t12 when both the main array power Pm in the main MPPT control unit 19 and the pilot power Pp in the pilot MPPT control unit 21 are obtained, the output determination unit 24 determines that the main array output Pm is N of the pilot output Pp. Judge whether it is more than double. Thereafter, the same operation is performed.

  Thus, in the first embodiment, when the main array output Pm or the wide sweep output Pw is N times or more of the pilot output Pp, the main MPPT control unit 19 is operated, and the main array output Pm is the pilot output Pp. When it is less than N times, the wide sweep control unit 22 is operated. The reason will be described below.

  When some of the main modules 13a to 13n and the pilot module 12 are shaded by the clouds, the main modules 13a to 13n and the pilot module 12 are in a state of being affected by the clouds.

  When both the main array 11 and the pilot module 12 are not affected by clouds, the solar radiation intensity of the main array 11 and the pilot module 12 is the same, so Pm = Pp × N. Further, when the pilot module 12 is affected by clouds and the main array 11 is not affected by clouds, the solar radiation intensity of the pilot module 12 is smaller than the solar radiation intensity of the main array 11, so that Pm> Pp × N. . That is, when Pm ≧ Pp × N, the main array 11 is hardly affected by clouds.

  Therefore, when the main array 11 is hardly affected by the clouds (when Pm ≧ Pp × N), the main array 11 continues the operation by the main MPPT control unit 19 as it is.

  Next, the main array output Pm is less than N times the pilot output Pp (Pm <Pp × N). For example, the pilot module 12 is not affected by the clouds, and the main array 11 is affected by the clouds. When When shadows occur in several places of the main array 11, not only the main array output Pm becomes small, but the main array output Pm has an output characteristic having a plurality of maximum values. In that case, the main array 11 may not be able to be operated with the maximum power.

  The output Pm of the main array is desirably operated at the maximum output among the plurality of maximum values, but the main MPPT control unit 19 does not necessarily operate at the maximum output. Therefore, the wide sweep control unit 22 searches for the maximum output operating voltage at the maximum maximum value among the plurality of maximum values.

  Next, a second embodiment of the present invention will be described. FIG. 3 is a configuration diagram of the control device for the photovoltaic power generation facility according to the second embodiment of the present invention. This second embodiment is different from the first embodiment shown in FIG. 1 in that when the number of times of operation selection by the wide sweep control unit 22 continuously exceeds a predetermined number of times, the operation selection switching unit 23 The operation selection monitoring unit 26 that notifies the effect is provided, and the operation selection switching unit 23 receives a notification from the operation selection monitoring unit 26 that the number of times of operation selection by the wide sweep control unit 22 has continuously exceeded a predetermined number of times. At that time, the operation selection of the wide sweep control unit 22 thereafter is prohibited, and the operation of the main MPPT control unit 19 is continued. The same elements as those in FIG. 1 are denoted by the same reference numerals, and redundant description is omitted.

  The operation selection monitoring unit 26 monitors the number of operation selections by the wide sweep control unit 22 in the operation selection switching unit 23. That is, it is determined whether or not the number of times of operation selection by the wide sweep control unit 22 has continuously exceeded a predetermined number of times. When the number of times of operation selection has exceeded the predetermined number of times, the operation selection switching unit 23 is notified accordingly.

  When the operation selection switching unit 23 receives notification from the operation selection monitoring unit 26 that the number of times of operation selection by the wide sweep control unit 22 has continuously exceeded the predetermined number of times, the operation selection of the wide sweep control unit 22 thereafter is selected. Is prohibited. Thereby, the changeover switch 20 becomes the main MPPT control unit 19 side, and the operation of the main MPPT control unit 19 is continuously performed.

  The reason why the operation selection of the wide sweep control unit 22 is prohibited when the number of operation selections by the wide sweep control unit 22 continuously exceeds a predetermined number of times is as follows.

  When the main array output Pm becomes less than N times the pilot output Pp (Pm <Pp × N), the operation selection switching unit 23 switches to the operation by the wide sweep control unit 22 and selects the maximum of the plurality of maximum values. Although the output point is searched, Pm <Pp × N is not only when the main array 11 is affected by the cloud, but is also one of the N main modules 13a to 13n constituting the main array 11. Even when a failure occurs, Pm <Pp × N.

  It is transient that the main array 11 is affected by the clouds and Pm <Pp × N. When the main array 11 and the pilot module 12 are no longer affected by the clouds, both have the same solar radiation intensity. Return Pm ≧ Pp × N.

  Therefore, when the state of Pm <Pp × N is continuously maintained, it can be determined that any of the N main modules 13a to 13n constituting the main array 11 has failed. Therefore, when the number of driving selections by the wide sweep control unit 22 continuously exceeds a predetermined number, the driving selection monitoring unit 26 notifies the driving selection switching unit 23, and the driving selection switching unit 23 When the notification is received, the main array 11 is fixed to the operation by the main MPPT control unit 19.

  According to the second embodiment, it can be determined that any of the N main modules 13a to 13n constituting the main array 11 has failed, and at that time, the operation by the unnecessary wide sweep control unit 22 is performed. Can be prevented.

  Next, a third embodiment of the present invention will be described. FIG. 4 is a configuration diagram of a control device for a photovoltaic power generation facility according to the third embodiment of the present invention. The third embodiment is different from the second embodiment shown in FIG. 3 in that the operation selection monitoring unit 26 continuously determines the number of times of operation selection by the wide sweep control unit 22 in addition to the operation selection switching unit 23. The output determination unit 24 is also notified that the number of times has been exceeded, and the output determination unit 24 has an offset value calculation unit 27, which is the number of times of operation selection by the wide sweep control unit 22. Is continuously greater than or equal to the predetermined number of times, the margin value ε is added to the absolute value | Pm−Pp × N | of the difference between the main array output Pm and the pilot output Pp times the predetermined number of times. The value is obtained as an offset value ΔPo.

  The operation selection monitoring unit 26 monitors the number of operation selections by the wide sweep control unit 22 in the operation selection switching unit 23. That is, it is determined whether or not the number of times of operation selection by the wide sweep control unit 22 has continuously exceeded a predetermined number of times, and when it has exceeded the predetermined number of times, the output determination unit 24 is notified of this.

  The output determination unit 24 includes an offset value calculation unit 27. The offset value calculation unit 27 notifies the operation selection monitoring unit 26 that the number of operation selections by the wide sweep control unit 22 has continuously exceeded a predetermined number of times. When received, a value obtained by adding a margin value ε to the absolute value | Pm−Pp × N | of the difference between the main array output Pm at the predetermined number of times and N times the pilot output Pp (| Pm−Pp × N | + Ε) is determined as the offset value ΔPo.

  After obtaining the offset value ΔPo, the output determination unit 24 obtains a value (Pm ′ + ΔPo) obtained by adding the offset value ΔPo to the main array output Pm ′ obtained by the operation of the main MPPT control unit 19, and this value is It is determined whether or not a value Pp × N which is N times the pilot output.

  That is, when the number of times of operation selection by the wide sweep control unit 22 is continuously equal to or greater than the predetermined number, it can be determined that a failure has occurred in any of the main modules 13a to 13n of the main array 11, and therefore the failed main module The value obtained by adding the offset value ΔPo to the main array output Pm ′ when power is generated by the remaining main module 13 excluding 13i (Pm ′ + ΔPo) is compared with the value obtained by multiplying the pilot output Pp by N (Pp × N). Then, it is determined whether or not the main array 11 is affected by the cloud. Then, when the main array 11 is affected by the clouds, the operation is switched to the operation by the wide sweep control unit 22 and the maximum output point among the plurality of maximum values is searched. The reason why the margin value ε is added is to suppress unnecessary operation selection of the wide sweep control unit 22.

  In the above description, the offset value ΔPo is obtained by adding the margin value ε to the absolute value | Pm−Pp × N | of the difference between the main array output Pm and the pilot output Pp times N (Pp × N) at a predetermined number of times. The absolute value of the difference between the main array output Pm and N times the pilot output Pp at each operation selection by the wide sweep control unit 22 | Pm−Pp × N The average value of || Pm−Pp × N | ave may be a value obtained by adding a margin value ε to | Pm−Pp × N | ave + ε. In this case, it can be set to an almost average value of the output decrease of the failed main module 13.

  Further, as the offset value ΔPo, the absolute value | Pm−Pp × N | of the difference between the main array output Pm and the N times the pilot output Pp at each operation selection by the wide sweep control unit 22 | Pm−Pp × A value obtained by adding a margin value ε to N | min may be set to | Pm−Pp × N | min + ε. In this case, it can be set to a value close to the output decrease of the failed main module 13.

  Further, as the offset value ΔPo, when the variation ΔPm of the main array output Pm in the maximum power follow-up control of the main MPPT control unit 19 is smaller than the predetermined variation value ΔPm0, and any one within the predetermined period T1 after noon A value | Pm−Pp × N | + ε obtained by adding a margin value ε to the absolute value | Pm−Pp × N | of the difference between the main array output Pm at the time and N times the pilot output Pp.

  For example, when operation switching to the wide sweep control unit 22 is prohibited by the operation selection switching unit 23, the operation is performed by the main MPPT control unit 19. In the operation state of the main MPPT control unit 19, the output determination unit 24 monitors the fluctuation ΔPm of the main array output Pm obtained by the maximum power follow-up control of the main MPPT control unit 19, and the fluctuation of the main array output Pm. A state in which ΔPm is smaller than a predetermined fluctuation value ΔPm0 is determined. This is because the state where the variation ΔPm of the main array output Pm is smaller than the predetermined variation value ΔPm0 is a state where the main array output Pm is stable and it can be determined that the state is not affected by clouds. is there.

  Further, the output determination unit 24 obtains the main array output Pm and the pilot output Pp at any point in time within the predetermined period T1 after noon in the state where the main array output Pm is stable. This is because it can be determined that the predetermined period T1 after noon is when the solar radiation intensity is the highest. Then, a value obtained by adding a margin value to the absolute value of the difference between the main array output Pm at any time within the predetermined period T1 after noon and N times the pilot output Pp (Pp × N) | Pm−Pp XN | + ε is determined as the offset value ΔPo.

  Thus, the offset value ΔPo can be made closer to the output decrease of the failed main module 13.

  According to the third embodiment, when the main array output Pm ′ is small due to a failure of some of the main modules 13 a to 13 n constituting the main array 11, the main array output characteristic has a plurality of maximum values. Even when the output characteristics are the same, the maximum output operating voltage can be searched without unnecessary continuous operation selection by the wide sweep control unit 22, and the operation can be efficiently performed with the maximum output.

DESCRIPTION OF SYMBOLS 11 ... Main array, 12 ... Pilot module, 13 ... Main module, 14 ... Main inverter, 15 ... AC system, 16 ... Pilot inverter, 17 ... Current detector, 18 ... Voltage detector, 19 ... Main MPPT control part, 20 DESCRIPTION OF SYMBOLS ... Changeover switch, 21 ... Pilot MPPT control part, 22 ... Wide sweep control part, 23 ... Operation selection switching part, 24 ... Output determination part, 25 ... Synchronous circuit, 26 ... Operation selection monitoring part, 27 ... Offset value calculation part

Claims (5)

In a control apparatus for a photovoltaic power generation facility, in which the main array is composed of N main modules having the same output characteristics, and has a pilot module having the same output characteristics as the main module, the maximum power follow-up control of the main array is performed at a predetermined cycle. A main MPPT control unit that outputs a voltage command determined by the maximum power tracking control to the main inverter, and a voltage command determined by the maximum power tracking control by performing the maximum power tracking control of the pilot module in synchronization with the main MPPT control unit. A pilot MPPT control unit for outputting the main inverter to the pilot inverter, and searching the maximum output operating voltage by moving the operating voltage of the main array within a predetermined voltage search range, and using the searched maximum output operating voltage as a voltage command, the main inverter At the same time as the maximum output operating power A wide sweep control unit that sets a voltage command of the main MPPT control unit, a main array output controlled by a voltage command of the main MPPT control unit, or a wide sweep output controlled by a voltage command of the wide sweep control unit; An output determination unit that compares N times the pilot output controlled by the voltage command of the pilot MPPT control unit and determines whether the main array output or the wide sweep output is N times or more the pilot output. And when the output determining unit determines that the main array output or the wide sweep output is N times or more of the pilot output, the operation of the main MPPT control unit is selected, and the output determining unit selects the main array When it is determined that the output or wide sweep output is less than N times the pilot output Control device for photovoltaic installations, characterized in that a driver selection switch unit for selecting operation of the wide sweep controller. It is determined whether or not the number of times of operation selection by the wide sweep control unit has continuously exceeded a predetermined number of times, and when it exceeds the predetermined number of times, an operation selection monitoring unit for notifying the operation selection switching unit is provided. When the operation selection switching unit receives a notification from the operation selection monitoring unit that the number of times of operation selection by the wide sweep control unit has continuously exceeded a predetermined number of times, the subsequent wide sweep control unit 2. The control device for photovoltaic power generation equipment according to claim 1, wherein the operation selection is prohibited and the operation of the main MPPT control unit is continued. In addition to the operation selection switching unit, the operation selection monitoring unit also notifies the output determination unit that the number of times of operation selection by the wide sweep control unit has continuously exceeded a predetermined number of times, and the output determination unit When receiving a notification from the operation selection monitoring unit that the number of times of operation selection by the wide sweep control unit has continuously exceeded a predetermined number of times, the main array output and the pilot output at the predetermined number of times A value obtained by adding a margin value to the absolute value of the difference from N times is obtained as an offset value, and thereafter, it is determined whether or not a value obtained by adding the offset value to the main array output is N times or more of the pilot output. The control device for a photovoltaic power generation facility according to claim 2. The offset value is a value obtained by adding a margin value to the absolute value of the difference between the main array output and the pilot output N times at a predetermined number of times. The control device for a photovoltaic power generation facility according to claim 4, wherein a margin value is added to an average value or a minimum value of absolute values of differences between the main array output and N times the pilot output. The offset value is a value obtained by adding a margin value to the absolute value of the difference between the main array output and N times the pilot output at a predetermined number of times, in the maximum power follow-up control of the main MPPT control unit. The absolute value of the difference between the main array output or wide sweep output and N times the pilot output at any time within a predetermined period after noon when the fluctuation of the main array output is smaller than a predetermined fluctuation value The control device for a photovoltaic power generation facility according to claim 4, wherein a margin value is added to the control value.

Images