KR101351748B1 - Controller for solar photovoltaic power generation and control method thereof - Google Patents

Abstract

The present invention relates to a photovoltaic power generator controller and a control method thereof. The control method of the photovoltaic power generator controller for controlling a photovoltaic power generator system to supply maximum power to the load by adjusting the reference value comprises the following steps: determining a partial shade state; and processing a global maximum power point tracking (MPPT) process when a partial shade state is determined. The global MPPT process comprises the following steps: finding an MPPT process point while converting a temporal reference value as much as a preset difference; determining the temporal reference value corresponding to a power peak value and the temporal reference value corresponding to the power peak value by processing a local MPPT process whenever local MPPT process points are found; setting a temporal reference value, as the global reference value, corresponding to the highest peak value as the local MPPT is processed at each local MPPT point; and setting the reference value based on the global reference value set at the previous step. [Reference numerals] (110) Main MPPT processing part; (111) Partial shade state determination part; (112) Counter; (113) Calling part; (120) Global MPPT processing part; (121) Local MPPT process point search part; (122) Local MPPT processing part; (123) Global reference command value determination part; (124) Return part

Description

Photovoltaic power generation control device and its control method {CONTROLLER FOR SOLAR PHOTOVOLTAIC POWER GENERATION AND CONTROL METHOD THEREOF}

The present invention relates to a solar power generation control device and a control method thereof, and more particularly, to a solar power generation control device and a control method that can generate the maximum power quickly even in a partial shadow state.

In general, the voltage and power curves of photovoltaic modules have unique characteristic curves as shown in FIG. 1.

In Figure 1 the horizontal axis on the graph is the voltage axis, the vertical axis is the power axis.

As shown in the figure, the maximum power that the photovoltaic module can generate under the same condition (for example, the condition of the same brightness and temperature of the sun) is the point where the ratio of the change in voltage and the change in power becomes zero, That is, it corresponds to the point (Ppeak) corresponding to the peak.

Therefore, in order for the photovoltaic module to supply maximum power, it is necessary to adjust the terminal voltage of the photovoltaic module to a voltage corresponding to the peak (Vpeak), and such voltage control uses an inverter circuit including a switching element. In this case, a pulse width modulation (PWM) signal having an appropriate duty ratio may be applied to the gate terminal of the switching device.

Here, the inverter circuit is configured to convert the DC voltage generated in the photovoltaic module into an alternating voltage, and it is only a known technique to change the terminal voltage of the photovoltaic module by the configuration and voltage control of the inverter circuit. Therefore, more detailed description will be omitted.

When the characteristics as shown in Figure 1, there are various algorithms for finding the maximum power point, for example, Perturb & Observe (aka P & O) and Incremental Conductance (aka IncCond).

The P & O method periodically increases and decreases the output voltage of the solar cell array and finds the maximum power operating point by comparing the previous output power with the current output power.The IncCond method compares the conductance and the incremental conductance of the solar cell output to the maximum. It is a method of following the power operating point.

Either way is the same in that it starts from a specific starting point and finds the part corresponding to the peak of FIG.

On the other hand, a solar cell, that is, one solar cell has a small output voltage, and thus several tens or in some cases hundreds are connected in series. Thus, a plurality of solar cells are assembled into one panel. It is called a (PHOTOVOLTAIC) module.

However, the photovoltaic module is composed of a plurality of such PV modules, that is, when some of the photovoltaic modules are shadowed, that is, some of the plurality of PV modules reach the sun light, but others do not reach the sun light It may occur that the intensity of light that is lost or reached reaches a considerable extent weaker than other PV modules.

As such, when the entire photovoltaic module is viewed as a whole, shading occurs in some areas is called a partial shading state.

When the partial shadow state occurs, the voltage and power characteristic curves of FIG. 1 are changed. For example, as shown in FIG.

In FIG. 2, an example in which the slope is 0, that is, two peaks on the graph correspond to one example, may be three or four more. Also, the position of the peak representing the highest point may vary depending on the state of partial shadowing. Can vary.

However, when there are several peaks on the voltage and power graphs, the maximum power point tracking method applied when only one peak is used does not allow rapid power point tracking or the wrong position may be determined as the maximum power point.

For example, although Ppeak1 and Ppeak2 points are generated in FIG. 2, even though the power of Ppeak1 point is greater than that of Ppeak2 point, the peak power point is 0 only because the ratio of the power change amount of the voltage change amount at Ppeak2 point is zero. You might be wrong.

However, regardless of whether a partial shadow occurs, scanning the entire area (ie finding the maximum power point by applying the reference voltage across all possible areas) can be a barrier to rapid control throughout the power tracking process.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and an object thereof is to provide a photovoltaic control device and a method of controlling the same, capable of quickly following a maximum power point even when a partial shadow state occurs.

In order to achieve the above object, a control method of a photovoltaic power generation control device for controlling a photovoltaic power generation system to supply maximum power to a load while adjusting a command value according to the present invention includes: determining a partial shadow state; And if it is determined that the partial shadowing state is a result of performing the global MPPT execution process, the global MPPT execution process may include local maximum power point tracking (MPPT) while changing the temporary reference command value by a predetermined interval. Finding an execution point; Whenever the local MPPT execution point is found, executing the local MPPT to determine a power peak value and a temporary reference command value corresponding to the power peak value; Selecting a temporary reference command value corresponding to the largest power peak value among the power peak values determined by executing the local MPPT at each local MPPT execution point, as the global reference command value; And setting the command value based on the global reference command value selected in the step.

Further, in order to achieve the above object, the photovoltaic power generation control device for controlling the photovoltaic power generation system to supply the maximum power to the load while adjusting the command value according to the present invention includes a partial shade state determination unit that determines a partial shade state. Wow; A local MPPT execution point search unit for searching for a local maximum power point tracking (MPPT) execution point while changing the temporary reference command value by a predetermined interval after the partial shadow state determination unit determines that the partial shadow state is determined; A local MPPT execution unit configured to determine a power peak value and a temporary reference command value corresponding to the power peak value by executing a local MPPT whenever the local MPPT execution point search unit finds a local MPPT execution point; The temporary reference command value corresponding to the largest power peak value among the power peak values determined by executing the local MPPT at each local MPPT execution point is selected as the global reference command value, and based on the selected global reference command value, And a global reference command value selection unit for setting a command value.

As described above, according to the present invention, even when a partial shadow state occurs in the photovoltaic power generation system, the maximum power point can be controlled. In particular, when searching for a local MPPT region, change the preset voltage interval (for example, by changing the reference voltage by a large amount) to quickly find the local MPPT region, and after finding the local MPPT region, run the local MPPT to calculate the voltage-power characteristic curve. We can find the exact maximum power point by finding the power peak points of the peaks corresponding to and comparing the power peak points of each peak.

In addition, even when the partial shadow state is gradually progressed and the occurrence of the partial shadow state is not detected, the global MPPT may be forcibly executed at each preset time, thereby reducing the maximum number of power point tracking failures.

1 is an example of a power-voltage characteristic curve of a solar power system in a steady state,
2 is an example of a power-voltage characteristic curve of a photovoltaic system in a partially shaded state,
3 is a functional block diagram of a solar power control apparatus according to an embodiment of the present invention,
4 to 6 is a control flowchart of the solar power control device according to an embodiment of the present invention,
FIG. 7 is a view illustrating a screen of capturing voltage and current waveforms at the time of comparing a result of executing a photovoltaic power generation control device according to an embodiment of the present invention.

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

The photovoltaic power generation control device 100 according to the present invention is a device for maximizing the power supplied by the photovoltaic module while adjusting a kind of command value. The power supplied by the power generation module can be maximized. As described above, the terminal voltage of the photovoltaic module can be changed by the interruption of the switching element of the inverter circuit, and since the configuration of such an inverter circuit and the like is only known in advance, a detailed description thereof will be omitted.

As described above, the solar power control apparatus 100 may perform voltage control, such as changing the terminal voltage of the solar power module, but various control methods may be performed, such as other current control.

However, for convenience of description below, the command value issued by the solar power control device 100 is an example of a voltage value.

The solar power control apparatus 100 according to the exemplary embodiment of the present invention may be configured to include a main MPPT execution unit 110 and a global MPPT execution unit 120 as shown in FIG. 1.

Here, the main MPPT execution unit 110 controls to follow the maximum power point in the normal state in which the partial shadow state does not occur (that is, the main MPPT execution control), and the maximum power when the partial shadow state does not occur in this way. The point tracking method may use a known technique using a P & O method or an IncCond method. All of these known techniques allow the maximum power point to be followed while adjusting the command value (for example, the reference voltage value) according to each algorithm. The following description of the main MPPT execution controlling to follow the maximum power point while adjusting the command value will be omitted as much as possible.

The main MPPT execution unit 110 may include a partial shadow state determination unit 111, a counter 112, and a caller 113.

The partial shadow state determining unit 111 performs a function of determining a partial shadow state, and for example, may determine whether a partial shadow state occurs by tracking a power change.

As another example, the partial shadow state may be determined in various ways, such as by examining the amount of change in conductance or impedance of the photovoltaic system or by using a brightness sensor for each PV module.

In the following description, for example, the partial shadow state determining unit 111 determines the partial shadow state according to the power change.

That is, the partial shadow state determination unit 111 is a case where the change in power supplied by the photovoltaic system at a predetermined interval (voltage interval or time interval) exceeds a preset value, and specifically falls below a preset value. It may be determined that the partial shadow state.

The counter 112 performs a count function, that is, a function of accumulating and storing time elapses. This function of the counter 112 is used by the calling unit 113 described later.

The caller 113 performs a function of calling the execution of the global MPPT execution unit 120 when a predetermined condition is satisfied while the main MPPT execution unit 110 is executed.

For example, the caller 113 may call execution of the global MPPT execution unit 120 when it is determined that the partial shadow state is determined as the partial shadow state. In this case, the call of execution of the global MPPT execution unit 120 means, for example, that each component included in the global MPPT execution unit 120 is controlled to operate.

As another example, the caller 113 detects the elapse of the preset time by the counter 112 even if the partial shaded state determination unit 111 does not make the partial shaded state. 120 may be invoked.

Meanwhile, as described above, the global MPPT execution unit 120 is executed when a partial shadow state occurs, and as illustrated in FIG. 3, the local MPPT execution point search unit 121 and the local MPPT execution unit 122 are executed. And a global reference command value selecting unit 123 and a returning unit 124.

The local MPPT execution point search unit 121 is first executed according to the call of the calling unit 113 after being determined as the partial shadow state as a result of the determination of the partial shadow state determination unit 111. Starts the process of finding the local maximum power point tracking (MPPT) execution point by changing the temporary reference command value (eg, the temporary reference voltage value) by the voltage interval).

Here, the temporary reference command value is a kind of control signal that allows the power supplied by the solar power generation system to be changed during the execution of the global MPPT execution unit 12. For example, the temporary reference command value may be changed according to the change of the temporary reference command value. The terminal voltage of is changed and eventually the power supplied by the photovoltaic system is changed.

The 'temporary reference command value' is the same as the 'command value' of the main MPPT execution unit described above in that it is a control signal for changing the magnitude of power supplied by the photovoltaic device 100, but the control signal is There is only a difference in that the generating subject is the global MPPT execution unit 120 driven according to the determination of the partial shadow state. The temporary reference command value may correspond to a voltage command value for voltage control or a current command value for current control.

As described above, the process of changing the terminal voltage of the photovoltaic system by supplying the temporary reference command value may be performed by controlling the switching element of the inverter circuit.

The local MPPT execution point refers to a point for starting local MPPT execution, and as shown in FIG. 2, when multiple peaks are formed in the voltage and power characteristic graph, the process of finding the peak point at each peak is performed by the local MPPT. This is a run, and such a local MPPT run is started at the local MPPT run point. A more detailed description thereof will be given later.

Specifically, the local MPPT execution point search unit 121 moves (changes) the temporary reference command value from the command value at the time when the partial shadow state is determined to the threshold value of the corresponding direction in either the negative direction or the positive direction. Then, the process of searching for a local MPPT execution point may be performed while moving the temporary reference command value from the command value at the time when the partial shadow state is determined to the threshold value of the corresponding direction in a direction opposite to the previously moved direction.

Hereinafter, the local MPPT execution point search unit 121 sequentially moves (changes) the temporary reference command value by a predetermined size starting from the command value at the time when the partial shadow state is determined and up to a predetermined minimum voltage threshold in the negative direction. Finds the local MPPT execution point, and then sequentially moves (changes) the temporary reference command value by a preset amount starting from the command value at the point where the partial shadow state was previously determined, up to the preset maximum voltage threshold in the positive direction. For example, find a local MPPT execution point.

The negative direction and the positive direction correspond to subtracting and increasing the temporary reference command value, respectively. The starting point of the negative or positive voltage shift with respect to the temporary reference command value is the point in time at which the partial shadow state is determined. It corresponds to the command value of, but the reference point may be changed during the movement.

That is, when the local MPPT execution point 121 finds a local MPPT execution point while the local MPPT execution point search unit 121 changes the temporary reference command value, the local MPPT execution unit 122 operates. Accordingly, when the power peak point is found, the temporary reference command value corresponding to the power peak point may be a reference point for the same direction movement (change).

In determining the local MPPT execution point, when the local MPPT execution point search unit 121 moves the temporary reference command value in the negative direction, the local MPPT execution point search unit 121 changes the command value (voltage) change amount at the corresponding temporary reference command value (voltage value) point. If the amount of power change is less than or equal to 0, it can be determined as a local MPPT execution point, and if the temporary reference command value is moved in the positive direction, the change in command value (voltage) at the corresponding temporary reference command value (voltage value) point If the power change for V is greater than or equal to 0, it can be determined as a local MPPT execution point. This will be described in more detail in the following flowchart.

As mentioned earlier, the local MPPT execution unit 122 executes the local MPPT whenever the local MPPT execution point search unit 121 finds the local MPPT execution point, and thus the power reference value and the temporary reference command value corresponding to the power peak value. To determine the function.

In this case, the power peak value determined by the local MPPT execution unit 122 and the temporary reference command value corresponding to the power peak value may be temporarily stored.

That is, the local MPPT execution unit 122 executes the local MPPT starting from the local MPPT execution point to determine the power peak value in the corresponding local MPPT region.

In this case, finding a local MPPT execution point means that each region where peaks exist is found as shown in FIG. 2. In this sense, an area where peaks exist can be referred to as a corresponding local MPPT region. The unit 122 executes a local MPPT to determine a power peak value in a corresponding peak presence region (ie, a corresponding local MPPT region), that is, a power value at a position corresponding to a peak peak.

In the present embodiment, the local MPPT region is an example including a peak, but the present invention is not limited thereto. The local MPPT region can be changed in various ways starting from the local MPPT execution point. Do.

In executing the local MPPT, a well-known technique using a P & O method or an IncCond method may be used, similar to the execution of the main MPPT described above, and a detailed description thereof will be omitted.

In this embodiment, 'global' and 'local' are terms borrowed to distinguish each other on the premise of the presence of several peaks appearing in a partially shaded state as shown in FIG. 'Global' is a term borrowed to emphasize the fact that the maximum power point is found throughout all available areas, and 'Local' is power for some sections of the whole area (e.g. for each peak containing area). The term is borrowed to highlight the point of finding the peak.

As such, since the local MPPT execution unit 122 is performed every time the local MPPT execution point search unit 121 discovers the local MPPT execution point, the local MPPT execution point search unit is again performed after such local MPPT execution process is terminated. The process of searching for another local MPPT execution point is repeated by 121.

The global reference command value selecting unit 123 selects a temporary reference command value corresponding to the largest power peak value among the power peak values determined in each local MPPT region corresponding to each local MPPT execution point as a global reference command value. Perform.

That is, the command value (voltage value) of the point having the largest power value among the peaks appearing in the partial shadow state is selected as the global reference command value to be reflected in the main MPPT execution process described above. For example, the global reference command value selecting unit 123 sets the command value of the main MPPT execution unit 110 to the same value as the global reference command value, so that the main MPPT execution unit 110 receives the newly set command value. As a basis, the main MPPT execution process is performed.

The return unit 124 ends the execution of the global MPPT execution unit 120 and returns to the main MPPT execution unit 110 when a predetermined condition is satisfied.

For example, the return unit 124 may return when the global reference command value is selected. However, when the difference in power change exceeds a preset value during the global MPPT execution process, the return unit 124 may exit and return to the global MPPT execution process. have.

For example, when there is a large power increase exceeding a preset value during the execution of the global MPPT, the partial shaded state may be regarded as being released, and thus the return unit 124 performs the global premise that the partial shaded state exists. It exits the MPPT execution process and makes the main MPPT execution process corresponding to the original MPPT execution process.

Hereinafter, a control process of the solar power generation control device 100 according to an embodiment of the present invention will be described with reference to FIGS. 4 to 6.

First, Figure 4 shows the process before entering the global MPPT execution.

First, an initial reference value for executing the main MPPT is set (step S1). For example, 85% of the Voc value measured when the solar power system is not connected to any load is referred to as the reference value (reference voltage). Value). However, this is an example and can be changed as much as possible.

The voltage and current generated by the photovoltaic power generation system are measured according to the set command value, and the P & O subroutine is called as an example for performing the main MPPT (step S3).

The execution of the P & O western routine is repeated until the maximum power point following is successful (step S5) (step S3).

After successful tracking of the maximum power point (step S5), a flag, which is a kind of variable, is set to 1, and the last MPP information, for example, Pmax_last (last power maximum measurement value) and Vm_last (voltage value corresponding to Pmax_last) are stored. (Step S7).

Then, the change amount of power ΔP is calculated (step S9), and if the change amount of power is not larger than the preset power change value (ΔP1: a predetermined value for determining whether the state is partially shaded) (step S11), it is normal. Since the state is maintained, the process returns to step S3 again.

If the change amount of power ΔP is greater than the preset power change value ΔP1 (step S11), it is determined that a partial shadow state has occurred, and after setting an initial value of a kind of variables (Vm_init = Vm_last, Vm_peak = Vref) (step S13), the execution of the global MPPT is called (step S15).

Hereinafter, the execution process of the global MPPT will be described with reference to FIG. 5.

First, the photovoltaic power generation control device 100 sets a temporary reference command value (Vref = Vm_last−i × ΔV1 × flag) (step S21), which is determined at the last command value Vm_last at the time when the partial shadow state is determined. It means that the predetermined command value interval ΔV1 is subtracted by the amount multiplied by a predetermined increment (i). The flag is used to determine the direction of movement (change) of the temporary reference command value. The flag is '1' when the temporary reference command value is moved in the negative direction, and '-1' when the temporary reference command value is moved in the positive direction. do.

Subsequently, the photovoltaic control device 100 calculates power after measuring voltage and current. When the change amount of power ΔP is larger than the preset change amount ΔP2 (step S23), the global MPPT control process is performed. It will exit and return to main MPPT control.

If the change amount ΔP of the power is greater than the change amount ΔP2 of the preset power, the solar power generation control device 100 determines that the partial shadow state is released and returns to the main loop (step S25). That is, the preset power change amount ΔP2 is a preset value for determining whether the partial shadow state is released.

If the change amount of power ΔP is not greater than the preset change amount of power ΔP2 (step S23), the conditional expression varies depending on the value of the flag (that is, according to the direction of movement of the reference voltage). If 1, it is determined whether the temporary reference command value is larger than the minimum threshold (step S29). If the flag is -1, it is determined whether the temporary reference command value is smaller than the maximum threshold (step S45).

If it is determined that the conditions are not met, that is, the temporary reference command value is not greater than the minimum threshold, the variables are reset to stop the movement in the negative direction and start the movement in the positive direction (flag = 1, i = 1, Vm_last = Vm_init) (step S43), the process returns to step S21 to move the temporary reference command value in the positive direction, and when the determination result is not smaller than the maximum threshold value (step S45). After determining that all movements in the positive direction are completed, the command value is set to a temporary reference command value (i.e., a global reference command value) corresponding to the maximum power value checked until then (step S47) so that the main MPPT is executed. It returns to (step S25). That is, the final Vm_peak value in step S47 corresponds to the global reference command value, and the command value used in the main MPPT execution process becomes the final determined Vm_peak.

When the determination result satisfies the conditions, that is, when the temporary reference command value is larger than the minimum threshold or the temporary reference command value is smaller than the maximum threshold, the slope at the point of the temporary reference command value (voltage value) (that is, dP / dV) is determined. ) Is calculated (step S31), and if the result of considering the flag value, that is, (flag × dP / dV) is less than or equal to 0 (step S33), the local MPPT execution point is determined to be found. For example, the P & O subroutine is called and stored new MPP information (for example, the new maximum power point size Pmax_new and the voltage value Vm_new at that time) (step S35).

If the new maximum power point size Pmax_new is larger than the existing maximum power point size Pmax_last (step S37), the variables are newly set (step S39) and the process returns to step S21 again.

If the new maximum power point size Pmax_new is not greater than the existing maximum power point size Pmax_last (step S37) or (flag x dP / dV) or the value is not less than 0 (step S33), the variable i is increased by one. After that (step S41), the process returns to step S21 to proceed again.

Accordingly, the photovoltaic control device 100 performs a process of finding a local MPPT execution point, and executes a local MPPT every time the local MPPT execution point is found, so that the power peak value in the local MPPT region and the temporary reference corresponding to the power peak value are found. The process of determining the command value is repeatedly performed.

In particular, it is possible to find the maximum power point in the range of all possible areas (ie, between the minimum threshold and the maximum voltage threshold) by measuring while moving in consideration of both the negative and the positive directions with respect to the reference voltage.

Figure 6 is to force the global MPPT execution even if the conditions described above, that is, the partial shadow state does not occur.

That is, after initializing the timer (step S51), starting the count (step S53), and when a predetermined time has elapsed (step S55), the global MPPT is called (step S57), which causes the occurrence of a partial shadow state. This is in case you don't know exactly.

That is, when the partial shadow state is not detected, the global MPPT is called at a preset time interval, thereby minimizing the maximum power point tracking failure due to the failure to detect the partial shadow state.

7 illustrates a process in which a conventional method and a result are changed according to a control process according to an embodiment of the present invention described above.

First, a voltage-current curve and a voltage-power curve of a photovoltaic system are shown in FIGS. 7 (a) and 7 (b). In particular, the voltage-power curve shows two peaks as a partial shadow state occurs. The first peak of which is shown is an example of a higher form.

According to the conventional method, even if a partial shadow state occurs during voltage control with the command value based on the voltage value of ①, the voltage is controlled to the command value based on the voltage value of the ① and the maximum power cannot be generated. When the partial shadow state occurs as in the present invention, the global MPPT execution process is performed and the entire region is scanned, and the command value based on the voltage value of point ② of FIG. ), The voltage can be controlled to generate the maximum power.

For reference, in FIG. 7B, the region A represents a slope, that is, a region in which dP / dV is greater than zero, and the region B represents a region in which the slope is less than zero. Determining whether to execute the local MPPT according to the slope is as described with reference to FIG. 5.

7 (c) shows an example of signal waveform changes of voltages and currents that appear in the global MPPT execution process according to the present invention. As shown in the figure, during the global MPTT execution, the voltage changes rapidly and the global reference command value is quickly found. It can be seen that.

The processes of each of the above-described embodiments can be made by a software program, which can also be stored in a computer readable recording medium.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the invention. It is to be understood that such variations and modifications are intended to be included in the scope of the appended claims.

100: solar power control device 110: main MPPT execution unit
120: global MPPT execution unit 111: partial shadow state determination unit
112: counter 113: calling part
121: Local MPPT execution point search unit 122: Local MPPT execution unit
123: Global reference command value selector
124: return unit

Claims (13)

In the control method of the photovoltaic power generation control device that controls the photovoltaic power generation system to supply the maximum power to the load while adjusting the command value,
(a) determining a partial shadow state;
(b) performing a global MPPT execution process when it is determined that the partial shadow state is determined as a result of the step (a);
The global MPPT execution process,
(b1) finding a local maximum power point tracking (MPPT) execution point while changing the temporary reference command value by a predetermined interval;
(b2) determining a power peak value and a temporary reference command value corresponding to the power peak value by executing the local MPPT every time the local MPPT execution point is found;
(b3) selecting a temporary reference command value corresponding to the largest power peak value among the power peak values determined by executing the local MPPT at each local MPPT execution point as a global reference command value;
and (b4) setting the command value based on the global reference command value selected in step (b3). The method of claim 1,
And controlling to exit the global MPPT execution process when the difference in power change during the global MPPT execution process exceeds a preset value. The method of claim 1,
(c) counting time;
(d) controlling the solar power generation control device to forcibly enter the global MPPT execution process when it is determined that the predetermined time interval is reached as a result of the time counting of step (c). Way. The method of claim 1,
Finding the local MPPT execution point of the step (b1),
(b11) moving the temporary reference command value from a command value at the time when the partial shadow state is determined to a threshold value in the direction in one of a negative direction and a positive direction;
(b12) moving the temporary reference command value from a command value at the time when the partial shadow state is determined to a threshold value in the direction opposite to the direction determined in the step (b11). Control method of solar power control device. 5. The method of claim 4,
In the step (b1),
When the temporary reference command value is moved in the negative direction, when the power change amount of the command value change amount at the temporary reference command value point is less than or equal to 0, it is determined that the local MPPT execution point. Control method of the device. 5. The method of claim 4,
When the temporary reference command value is moved in the positive direction, when the power change amount of the command value change amount at the temporary reference command value point is greater than or equal to 0, it is determined that the local MPPT execution point. Control method of the device. A computer-readable recording medium storing a program for executing the method according to any one of claims 1 to 6. In the photovoltaic control device for controlling the photovoltaic system to supply the maximum power to the load while adjusting the command value,
A partial shadow state determining unit determining a partial shadow state;
A local MPPT execution point search unit for searching for a local maximum power point tracking (MPPT) execution point while changing the temporary reference command value by a predetermined interval after the partial shadow state determination unit determines that the partial shadow state is determined;
A local MPPT execution unit configured to determine a power peak value and a temporary reference command value corresponding to the power peak value by executing a local MPPT whenever the local MPPT execution point search unit finds a local MPPT execution point;
The temporary reference command value corresponding to the largest power peak value among the power peak values determined by executing the local MPPT at each local MPPT execution point is selected as the global reference command value, and the command is based on the selected global reference command value. And a global reference command value selection unit for setting a value. 9. The method of claim 8,
The partial shadow state determination unit is included in the main MPPT execution unit that performs the main MPPT execution while adjusting the command value according to a preset algorithm,
The local MPPT execution point search unit, the local MPPT execution unit, and the global reference command value selection unit are included in a global MPPT execution unit executed by a call of the main MPPT execution unit,
The global MPPT execution unit further comprises a return unit which exits the global MPPT execution process when the difference in power change during the global MPPT execution process exceeds a preset value. 10. The method of claim 9,
The main MPPT execution unit,
A counter for counting time;
And a caller for calling the global MPPT execution unit when it is determined that the predetermined time interval is reached as a result of the time count of the counter. 9. The method of claim 8,
The local MPPT execution point search unit moves the temporary reference command value from the command value at the time when the partial shadow state is determined to either the negative direction or the positive direction threshold to the threshold value of the corresponding direction, and then partially shades the state. And a local MPPT execution point while moving the reference command value from the command value at the time point at which it is determined to the threshold value of the corresponding direction in a direction opposite to the moved direction. 12. The method of claim 11,
The local MPPT execution point search unit may determine that the local MPPT execution point is less than or equal to 0 when the power change amount of the command value change amount at the temporary reference command value point when the temporary reference command value is moved in the negative direction. Photovoltaic power generation control device, characterized in that. 12. The method of claim 11,
The local MPPT execution point search unit determines that the local MPPT execution point is equal to or greater than 0 when the power change amount corresponding to the change in the command value at the temporary reference command value point when the temporary reference command value is moved in the positive direction. Photovoltaic power generation control device, characterized in that.

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