JP6618870B2 - Power conversion device for solar power generation, control method, and solar power generation system - Google Patents

Description

  The present invention relates to a power conversion device for photovoltaic power generation, a control method, and a photovoltaic power generation system.

  The solar power generation power conversion device is a power conversion device that converts DC power generated by a solar panel into AC power and supplies power to the power system.

  An example of a photovoltaic power converter is an inverter. In this case, the inverter converts the DC power output from the solar panel into AC power having a commercial frequency and transmits it to the power system. Another example includes a chopper and an inverter. In this method, the DC power output from the solar panel is boosted by a chopper, and the inverter converts the DC power output from the chopper into AC power having a commercial frequency and transmits it to the power system.

  In such a power conversion apparatus for photovoltaic power generation, generally, maximum power tracking (MPPT) control is performed so that the output power of the solar panel is maximized. The maximum power follow-up control is control that adjusts the panel voltage of the solar panel so that the output power of the solar panel becomes maximum by following the output characteristics of the solar panel that change depending on the surrounding environment. Such maximum power tracking control is performed by an inverter or chopper adjusting the panel voltage of the solar panel.

  On the other hand, electric power must always balance supply and demand. When there is too much supply for the demand for electric power, there is a risk that a stable supply of electric power may be hindered, such as a power outage. In order to avoid such a situation, the photovoltaic power conversion device is required to control the output of the solar panel in accordance with an output command from an electric power company.

  Patent Document 1 describes a photovoltaic power conversion apparatus that stops maximum power tracking control and suppresses output power according to an output power suppression command when output power suppression is required.

JP 2013-183578 A

  However, when the maximum power tracking control is stopped according to the output power suppression command and the output power is suppressed, the output power suppression may not be achieved depending on the output characteristics of the solar panel. For example, when a part of the solar panel is shaded by the influence of clouds or the like, the output characteristics of the solar panel may change greatly.

  For example, specifically, in a photovoltaic power conversion device connected to a solar panel having output characteristics having a plurality of convex shapes without taking the convex output characteristics having a maximum value of one point, Patent Literature When the maximum power follow-up control is stopped and the control is performed to reduce the output power as in 1, a situation occurs in which the output tends to increase despite the output power suppression command being issued. In addition, since the shadow on the solar panel changes from time to time, the output characteristics of the solar panel change with time, and the output of the power converter for photovoltaic power generation also fluctuates accordingly.

  From the above, in the present invention, in accordance with the output power suppression command, the photovoltaic power conversion device, the control method, and the solar power provided with the control device and the like that can appropriately suppress the output of the photovoltaic power conversion device It aims to provide a power generation system.

  In order to solve the above-described problems, in the present invention, a power converter for photovoltaic power generation that converts DC power output from a solar panel into AC power by a power converter and outputs the AC power to a system, the power converter The control unit for controlling the DC voltage control unit for controlling the panel voltage of the solar panel and the active power control unit for controlling the output power of the power converter, the DC voltage control unit of the DC voltage control unit according to an external command The power converter for photovoltaic power generation is characterized in that the output and the output of the active power control unit are switched to give a gate pulse signal for driving the power converter.

  Furthermore, the present invention is a method for controlling a power converter for photovoltaic power generation that converts DC power output from a solar panel into AC power by a power converter and outputs the AC power to a system, and a control unit that controls the power converter Has a DC voltage control unit that controls the panel voltage of the solar panel and an active power control unit that controls the output power of the power converter, and the output of the DC voltage control unit and active power control according to an external command The output of the unit is switched to give a gate pulse signal for driving the power converter, and the maximum voltage follow-up control is performed by the DC voltage control unit in the steady state, and when the command from the outside is given, the active power control The control method for the photovoltaic power converter is characterized in that the output suppression control is performed by the unit, and then the panel voltage control is performed by the DC voltage control unit after reaching the predetermined output. Than it is.

  Furthermore, the present invention includes a solar panel and a photovoltaic power generation power conversion device that converts DC power output from the solar panel into AC power by a power converter and outputs the AC power to the system, and controls the power converter. The control unit includes a DC voltage control unit that controls the panel voltage of the solar panel and an active power control unit that controls the output power of the power converter, and the output of the DC voltage control unit according to an external command. The solar power generation system is characterized in that the output of the active power control unit is switched to give a gate pulse signal for driving the power converter.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the control apparatus etc. which the power converter device for photovoltaic power generation can suppress output appropriately according to an output electric power suppression instruction | command.

The figure which shows the structure of the power converter device for solar power generation concerning Example 1 of this invention. The figure which shows an example of the characteristic of a solar panel. The figure which shows the operation | movement waveform when the output suppression control of this invention is performed. The figure which shows the structure of the power converter device for solar power generation concerning Example 2 of this invention. The figure which shows an example of the panel characteristic when the solar radiation amount to a solar panel changes. The figure which shows the operation | movement waveform at the time of making it transfer to the operation point G2 instead of the operation point G. The figure which shows the structure of the power converter device for solar power generation concerning Example 3 of this invention. The figure which shows the structure of the power converter device for solar power generation concerning Example 4 of this invention. The figure which shows the structure of the power converter device for solar power generation concerning Example 5 of this invention. The figure which shows the structure of the power converter device for solar power generation concerning Example 6 of this invention.

  DESCRIPTION OF EMBODIMENTS Hereinafter, a photovoltaic power converter according to the present invention and embodiments thereof will be described with reference to the drawings.

  FIG. 1 shows a configuration of a power converter for photovoltaic power generation according to Embodiment 1 of the present invention. The power conversion device 26 for photovoltaic power generation according to the first embodiment includes a solar panel 1, an inverter 2 that is a power converter, a voltage detector 4, a current detector 5, a voltage detector 6, a current detector 7, and a control unit 8. It is composed of

  The solar panel 1 is connected to the DC part of the inverter 2, and the AC part of the inverter 2 is connected to the three-phase power system 3. The inverter 2 converts the DC power supplied from the solar panel 1 into AC power and supplies it to the power system 3.

  The voltage detector 4 is provided on the output side of the solar panel 1 and detects the output voltage of the solar panel 1. The output voltage of the solar panel 1 is the same as the DC voltage of the inverter 2, and the voltage detector 4 can also be said to detect the DC voltage of the inverter 2. The current detector 5 is provided on the output side of the solar panel 1 and detects the output current of the solar panel 1. The output current of the solar panel 1 is the same as the input current to the DC part of the inverter 2, and it can be said that the input current to the DC part of the inverter 2 is detected. The voltage detector 6 is provided on the output side of the inverter 2 and detects a system voltage of a system connected to the inverter 2. The current detector 7 detects an output current output to a system connected to the inverter 2.

  The voltage detection value and the current detection value detected by the voltage detector 4, the current detector 5, the voltage detector 6, and the current detector 7 are input to the control unit 8. An external command 100 is input to the control unit 8. This external command 100 is an output suppression command that is input when the output of the photovoltaic power conversion device 26 is suppressed. The control unit 8 performs a predetermined calculation based on the input voltage detection value, current detection value, and external command 100, and outputs a gate pulse signal 101 for driving the inverter 2.

  The external command receiving unit 9 receives the external command 100 and outputs an output suppression command to the output suppression control unit 10. The output suppression control unit 10 receives the output suppression command output from the external command receiving unit 9 and outputs an output power command to the active power control unit 11 and a switching command to the changeover switch 12.

  The active power control unit 11 receives the voltage detection value of the system voltage of the power system 3, the current detection value of the output current flowing from the inverter 2 to the power system 3, and the output power command output by the output suppression control unit 10. Performs active power control so that the output power output to the power system 3 matches the output power command, and outputs an output current command to the inverter 2.

  The DC voltage control unit 13 receives the voltage detection value of the output voltage of the solar panel 1 and the current detection value of the output current as inputs, and performs maximum power tracking control so that the output power of the solar panel 1 is maximized. The output voltage command of the solar panel 1 is calculated, DC voltage control is performed so that the output voltage of the solar panel 1 matches the output voltage command, and the output current command to the inverter 2 is output.

  The change-over switch 12 receives an output current command output from the active power control unit 11, an output current command output from the DC voltage control unit 13, and a switch command output from the output suppression control unit 10 as input, and a power converter for photovoltaic power generation When the output of 26 is suppressed, the output current command output from the active power control unit 11 is selected and output. Otherwise, the output current command output from the DC voltage control unit 13 is selected and output.

  The current control unit 14 receives the output current command output from the changeover switch 12, the voltage detection value of the system voltage of the power system 3, and the current detection value of the output current flowing from the inverter 2 to the power system 3. Current control is performed so that the output current flowing to 3 matches the output current command, and the output voltage command of the inverter 2 is output.

  The PWM control unit 15 receives the output voltage command output from the current control unit 14, performs PWM (Pulse Width Modulation) control, and outputs a gate pulse signal 101 for driving the inverter 2.

  FIG. 2 shows an example of panel characteristics when the solar panel 1 is partially shaded. The illustrated panel characteristic represents the relationship between the panel voltage (horizontal axis) and the panel output (vertical axis), and has an output characteristic having a plurality of convex shapes. In FIG. 2, an operating point S is an operating point when the maximum power follow-up control is performed by the DC voltage control unit 13 in the solar power generation power converter 26. The operating point G is an operating point when the output suppression control is performed by the active power control unit 11 in the photovoltaic power conversion device 26. P1 and P2 are operating points indicating minimum and maximum output characteristics having a plurality of convex shapes, and P3 is an arbitrary operating point.

In FIG. 2, the relationship between the panel voltage (horizontal axis) and the panel output (vertical axis) at each operating point is shown as a symbol. For example the panel voltage of the operating point S is Vs, the panel output is Ps, the panel voltage of the operating point G is V _G, the panel output is P _G. According to the panel characteristic PN of this figure, when operating at the operating point S, in order to shift the operating point to the operating point G given the output suppression command from the outside, the panel voltage by the DC voltage control unit 13 when equally varied toward the V _G from Vs, can be seen that cause fluctuations in the panel output.

FIG. 3 shows operation waveforms when the output suppression control of the present invention is executed. In FIG. 3, the horizontal axis represents time, and from time 0 to time T _s, maximum power follow-up control is performed by the DC voltage controller 13 in the photovoltaic power converter 26. From time T _s to time T _G, output suppression control is performed by the active power control unit 11 in the photovoltaic power conversion device 26. After the time _TG , the panel voltage control is performed by the DC voltage control unit 13 in the photovoltaic power conversion device 26.

  The vertical axis in FIG. 3 shows the output power and panel voltage of the solar panel 1. In FIG. 3, in the state where the maximum power follow-up control, which is the initial state, is performed, the inverter 2 operates according to the output current command output from the DC voltage control unit 13. The output current command output by the DC voltage controller 13 at this time corresponds to the operating point S in FIG. 2 and realizes the panel voltage Vs and the panel output Ps.

At time T _s , the photovoltaic power conversion device 26 starts an output suppression operation in response to an external command. At this time, the output suppression control unit 10 provides the active power control unit 11 with a target signal (output power command) of active power that decreases at a constant rate of time change from time T _s to time _TG . The active power control unit 11 performs active power control according to the output power command output from the output suppression control unit 10, and the inverter 2 operates according to the output current command output from the active power control unit 11.

  Therefore, when the output power command output from the output suppression control unit 10 is reduced, the output power of the inverter 2 is reduced according to the output power command. When the output power of the inverter 2 is reduced, the difference power between the output power of the solar panel 1 and the output power of the inverter 2 is accumulated in the DC circuit of the inverter 2, so that the DC voltage of the inverter 2, that is, the output of the solar panel 1 The voltage rises, the output power of the solar panel 1 decreases, and becomes equal to the output power of the inverter 2.

In addition, since the said control is implemented with respect to the solar panel which has the output characteristic which has the some convex shape shown in FIG. 2, when the operation | movement of FIG. 3 is described corresponding to each operation point of FIG. It seems to be. First, when the output power command is reduced from P _S to P _P1 from time T _S to time T _P1 , the output power of the inverter 2 and the output power of the solar panel 1 are reduced from P _S to P _P1. the output voltage of the panel 1 rises from _{V S} to _{V P1.} At this time, in FIG. 2, the operating point has shifted from the operating point S to the operating point P1.

Then, when the output power command from time _{T P1} to time _{T P3} reduced from _{P P1} to _{P P3,} the output power of the inverter 2 is reduced from _{P P1} to _{P P3} according to the output power command. On the other hand, the output power of the solar panel 1 transiently increases from P _P1 to P _P2 and then decreases to P _P3 . This is because the output characteristic of the solar panel 1 is a local maximum point at the operating point P2 as shown in FIG.

The output voltage of the solar panel 1 rises from V _P1 to V _P3 via V _P2 . At this time, in FIG. 2, the operating point has shifted from the operating point P1 to the operating point P3 via the operating point P2. In addition, although not shown in figure, it becomes the operation | movement which decreases after the output current of the solar panel 1 also rises transiently.

Then, when the output power command from time _{T P3} to time _{T G} is reduced from _{P P3} to _{P G,} the output power and the output power of the solar panel 1 of the inverter 2 from the _{P P3} according to the output power command to _{P G} reduced, the output voltage of the solar panel 1 rises from _{V P3} to _{V G.} At this time, the operating point in FIG. 2 has shifted from the operating point P3 to the operating point PG.

After time _{TG, the} inverter 2 is operated again in accordance with the output current command output by the DC voltage control unit 13. However, this time not the maximum power follow-up control, the output voltage of the panel 1 is controlled so as to maintain at V _G. In this way, it is possible to maintain the output of the inverter 2 at P _G.

  As described above, by switching the control method from the DC voltage control for controlling the output voltage of the solar panel 1 to the active power control for controlling the output power of the inverter 2, it is possible to follow the output suppression command from the outside. It becomes possible. Moreover, the state which suppressed the output can be maintained by switching to the DC voltage control which controls the output voltage of the solar panel 1 again after that.

  FIG. 4 shows the configuration of a photovoltaic power conversion apparatus according to Embodiment 2 of the present invention. The power conversion device for photovoltaic power generation 26 of the second embodiment is different from FIG. 1 in that the output voltage of the solar panel 1 output from the voltage detector 4 is input, and an output power correction command is issued to the output suppression control unit 10. It is a point provided with the panel voltage monitoring part 16 to output.

  The panel voltage monitoring unit 16 functions to prevent a decrease in the output voltage of the solar panel 1 when the amount of solar radiation decreases during the output suppression operation. The first embodiment is described on the assumption that a sufficient amount of solar radiation is obtained during the output suppression operation period. In practice, however, the amount of solar radiation may suddenly decrease during this period. When the amount of solar radiation decreases, the maximum power that can be output from the solar panel 1 also decreases. Therefore, if the inverter 2 tries to output power that is larger than the maximum power that can be output from the solar panel 1, the shortage of power is converted to the direct current of the inverter 2. Since the compensation is made from the energy stored in the circuit, the DC voltage of the inverter 2, that is, the output voltage of the solar panel 1 is lowered.

  Therefore, the panel voltage monitoring unit 16 monitors the output voltage of the solar panel 1 and outputs an output power correction command to the output suppression control unit 10 when the output voltage of the solar panel 1 falls below a predetermined value. Thus, the correction control is performed so that the output power of the inverter 2 is reduced.

  FIG. 5 shows an example of panel characteristics when the amount of solar radiation on the solar panel changes. In FIG. 5, the panel characteristics PN1 when the amount of solar radiation is large and the panel characteristics PN2 when the amount of solar radiation are small are shown together as panel characteristics. In FIG. 5, an operating point S is an operating point on the panel characteristic PN1 when the maximum power tracking control is performed when the amount of solar radiation is large. On the other hand, on the panel characteristic PN1, when the operation point is shifted from the operation point S to the operation point G to suppress the output and the solar radiation amount is reduced, the operation point is a panel characteristic when the solar radiation amount is small. Transition to PN2. As a result, on the panel characteristic PN2 when the amount of solar radiation is small, it is impossible to shift to the operating point G, and it is only possible to shift to the operating point G2 close to the operating point G.

FIG. 6 shows an operation waveform when shifting to the operation point G2 on the panel characteristic PN2 instead of the operation point G on the panel characteristic PN1. 6, from time 0 to time T _S has performed the maximum power follow-up control, the inverter 2 is operating in accordance with the output current command output from the DC voltage control unit 13.

When starting the output suppression operation from time T _S, the inverter 2 in accordance with the output current command output suppression control unit 10 is active power control unit 11 is implemented active power control according to the output power command for outputting, active power controller 11 outputs Will work. Therefore, when the output power command output from the output suppression control unit 10 is reduced, the output power of the inverter 2 is reduced according to the output power command. When the output power of the inverter 2 is reduced, the difference power between the output power of the solar panel 1 and the output power of the inverter 2 is accumulated in a capacitor provided in the DC circuit of the inverter 2, so that the DC voltage of the inverter 2, that is, the sun The output voltage of the light panel 1 increases, the output power of the solar panel 1 decreases, and becomes equal to the output power of the inverter 2.

Then, the amount of solar radiation is reduced at time T _D, the output of the solar panel 1 and lowered. At this time, the difference power between the output power of the solar panel 1 and the output power of the inverter 2 is compensated from the energy accumulated in the DC circuit of the inverter 2, so that the DC voltage of the inverter 2, that is, the output of the solar panel 1. The voltage drops.

Next, at time T _L, the output voltage of the solar panel 1 when lower than a predetermined value V _L, the panel voltage monitoring unit 16 outputs the output power correction command to the output suppression control unit 10. When receiving the output power correction command output from the panel voltage monitoring unit 16, the output suppression control unit 10 reduces the output power command output to the active power control unit 11 until the decrease in the output voltage of the solar panel 1 is subsided.

Next, at time T _M, the decrease in the output voltage of the solar panel 1 fits, the inverter 2 is operated again in accordance with the output current command output from the DC voltage control unit 13. At this time, the DC voltage control unit 13 performs the maximum power follow-up control to maintain the output voltage of the solar panel 1 at _VG2 . By doing in this way, the output of the inverter 2 can be maintained at _PG2 .

  As described above, by switching the control method from the DC voltage control for controlling the output voltage of the solar panel 1 to the active power control for controlling the output power of the inverter 2, it is possible to follow the output suppression command from the outside. It becomes possible. Further, even when the amount of solar radiation is reduced during active power control, it is possible to suppress a decrease in the output voltage of the solar panel 1 and continue operation.

  FIG. 7: shows the structure of the power converter device for solar power generation concerning Example 3 of this invention. The solar power generation power converter 26 according to the third embodiment is different from FIG. 1 in that the solar radiation amount detection unit 17 that detects the solar radiation amount and the solar radiation amount detection value output by the solar radiation amount detection unit 17 are used as input to suppress output. The solar radiation amount monitoring unit 18 that outputs an output power correction command to the control unit 10 is provided.

  The solar radiation amount monitoring unit 18 functions to prevent a decrease in the output voltage of the solar panel 1 when the solar radiation amount decreases during the output suppression operation. When the amount of solar radiation decreases, the maximum power that can be output from the solar panel 1 also decreases. Therefore, if the inverter 2 tries to output power that is larger than the maximum power that can be output from the solar panel 1, the shortage of power is converted to the DC of the inverter 2. Since the compensation is made from the energy stored in the circuit, the DC voltage of the inverter 2, that is, the output voltage of the solar panel 1 is lowered.

  Therefore, the solar radiation amount monitoring unit 18 monitors the solar radiation amount detection value output from the solar radiation amount detection unit 17, and when the solar radiation amount decreases, outputs an output power correction command to the output suppression control unit 10 to Reduce output power.

  In this way, by monitoring the amount of solar radiation even when the amount of solar radiation is reduced during active power control, the decrease in the output voltage of the solar panel 1 is suppressed and the operation is continued as in the second embodiment. Is possible.

  FIG. 8: shows the structure of the power converter device for solar power generation concerning Example 4 of this invention. In the first to third embodiments, the power converter is configured by the inverter 2, but in the fourth embodiment, the power converter is configured by the chopper 19 and the inverter 2. For this reason, the photovoltaic power generation power converter 29 of the fourth embodiment is different from the first to third embodiments in the configuration of the power main circuit and the control device. This difference is as follows.

  The solar power generation power converter 29 according to the fourth embodiment includes a solar panel 1, a chopper 19, a voltage detector 4, a current detector 5, a voltage detector 20, a current detector 21, an inverter 2, a voltage detector 6, It has a current detector 7 and a control unit 22.

  The solar panel 1 is connected to the input side of the chopper 19, the output side of the chopper 19 is connected to the DC part of the inverter 2, and the AC part of the inverter 2 is connected to the three-phase power system 3. The chopper 19 boosts the DC power supplied from the solar panel 1 and supplies it to the inverter 2. The inverter 2 converts the DC power supplied from the chopper 19 into AC power and supplies it to the power system 3.

  The voltage detector 4 is provided on the output side of the solar panel 1 and detects the output voltage of the solar panel 1. The output voltage of the solar panel 1 is the same as the DC voltage on the input side of the chopper 19, and the voltage detector 4 can also be said to detect the DC voltage on the input side of the chopper 19. The current detector 5 is provided on the output side of the solar panel 1 and detects the output current of the solar panel 1. The output current of the solar panel 1 is the same as the input current to the input side of the chopper 19, and it can be said that the input current to the input side of the chopper 19 is detected. The voltage detector 20 is provided on the output side of the chopper 19 and detects a DC voltage on the output side of the chopper 19. The DC voltage on the output side of the chopper 19 is the same as the DC voltage of the inverter 2, and it can be said that the DC voltage of the inverter 2 is detected. The current detector 21 is provided on the output side of the chopper 19 and detects the output current on the output side of the chopper 19. The output current on the output side of the chopper 19 is the same as the input current to the DC part of the inverter 2, and it can be said that the input current to the DC part of the inverter 2 is detected. The voltage detector 6 is provided on the output side of the inverter 2 and detects a system voltage of a system connected to the inverter 2. The current detector 7 detects an output current output to a system connected to the inverter 2.

  The voltage detection value and the current detection value detected by the voltage detector 4, the current detector 5, the voltage detector 20, the current detector 21, the voltage detector 6, and the current detector 7 are input to the control unit 22. An external command is input to the control unit 22. This external command is an output suppression command that is input when the output of the photovoltaic power converter 29 is suppressed.

  The control unit 22 performs a predetermined calculation based on the input voltage detection value, current detection value, and external command, and outputs a gate pulse signal for driving the chopper 19 and the inverter 2. The external command receiving unit 9 receives the external command and outputs an output suppression command to the output suppression control unit 10. The output suppression control unit 10 receives the output suppression command output from the external command receiving unit 9 and outputs an output power command to the active power control unit 11 and a switching command to the changeover switch 12.

  The active power control unit 11 receives the output side voltage detection value and current detection value of the chopper 19 and the output power command output from the output suppression control unit 10, and the output power output by the chopper 19 to the DC unit of the inverter 2 is output. Active power control is performed so as to coincide with the power command, and an output voltage command to the chopper 19 is output.

  The DC voltage control unit 13 receives the voltage detection value of the output voltage of the solar panel 1 and the current detection value of the output current, and performs maximum power follow-up control so that the output power of the solar panel 1 is maximized. The output voltage command of the optical panel 1 is calculated, DC voltage control is performed so that the output voltage of the solar panel 1 matches the output voltage command, and the output voltage command to the chopper 19 is output.

  The change-over switch 12 receives the output voltage command output from the active power control unit 11, the output voltage command output from the DC voltage control unit 13, and the switch command output from the output suppression control unit 10 as input, and the photovoltaic power generation power conversion device 29. When the output is suppressed, the output voltage command output from the active power control unit 11 is selected and output. In other cases, the output voltage command output from the DC voltage control unit 13 is selected and output. The PWM control unit 15 receives an output voltage command output from the changeover switch 12, performs PWM (Pulse Width Modulation) control, and outputs a gate pulse signal for driving the chopper 19.

  The DC voltage control unit 23 receives the DC voltage detection value of the DC part of the inverter 2 as input, performs DC voltage control so that the DC voltage of the DC part of the inverter 2 becomes constant, and outputs an output current command to the inverter 2 . The current control unit 24 receives the output current command output from the DC voltage control unit 23, the voltage detection value of the system voltage of the power system 3, and the current detection value of the output current flowing from the inverter 2 to the power system 3. Current control is performed so that the output current flowing to the system 3 matches the output current command, and the output voltage command of the inverter 2 is output. The PWM control unit 25 receives the output voltage command output from the current control unit 24, performs PWM (Pulse Width Modulation) control, and outputs a gate pulse signal for driving the inverter 2.

  Thus, also in the configuration of the fourth embodiment including the chopper 19 and the inverter 2, the output of the chopper 19 is controlled from the DC voltage control that controls the output voltage of the solar panel 1 as in the first, second, and third embodiments. By switching the control method to active power control for controlling power, it is possible to follow an output suppression command from the outside. Moreover, the state which suppressed the output can be maintained by switching to the DC voltage control which controls the output voltage of the solar panel 1 again after that.

  FIG. 9 shows a configuration of a photovoltaic power conversion apparatus according to Embodiment 5 of the present invention. What is different from FIG. 8 in the power converter 29 for photovoltaic power generation of the fifth embodiment is that the output voltage of the solar panel 1 output from the voltage detector 4 is input, and an output power correction command is output to the output suppression control unit 10. The panel voltage monitoring unit 16 is provided.

  The panel voltage monitoring unit 16 prevents a decrease in the output voltage of the solar panel 1 when the amount of solar radiation decreases during the output suppression operation. If the amount of solar radiation decreases, the maximum power that can be output from the solar panel 1 also decreases. Since the compensation is made from the energy stored in the DC circuit on the side, the DC voltage on the input side of the chopper 19, that is, the output voltage of the solar panel 1 is lowered.

  Therefore, the panel voltage monitoring unit 16 monitors the output voltage of the solar panel 1, and outputs an output power correction command to the output suppression control unit 10 when the output voltage of the solar panel 1 falls below a predetermined value. The output power of the chopper 19 is made small.

Thus, also in the structure of the present Example comprised from the chopper 19 and the inverter 2,
Even when the amount of solar radiation is reduced during active power control, the DC voltage on the input side of the chopper 19 is monitored to suppress a decrease in the output voltage of the solar panel 1 as in the second embodiment, and the operation is continued. It becomes possible to do.

  FIG. 10: shows the structure of the power converter device for solar power generation concerning Example 6 of this invention. What is different from FIG. 8 in the solar power generation power conversion device 29 of the sixth embodiment is that the solar radiation amount detection unit 17 that detects the solar radiation amount and the solar radiation amount detection value that is output from the solar radiation amount detection unit 17 are input to suppress output. The solar radiation amount monitoring unit 18 that outputs an output power correction command to the control unit 10 is provided.

  The solar radiation amount monitoring unit 18 prevents a decrease in the output voltage of the solar panel 1 when the solar radiation amount decreases during the output suppression operation. When the amount of solar radiation decreases, the maximum power that can be output from the solar panel 1 also decreases. Therefore, when the chopper 19 tries to output a power that is larger than the maximum power that can be output from the solar panel 1, the insufficient power is input to the chopper 19. Since the compensation is made from the energy stored in the DC circuit on the side, the DC voltage on the input side of the chopper 19, that is, the output voltage of the solar panel 1 is lowered.

  Therefore, the solar radiation amount monitoring unit 18 monitors the solar radiation amount detection value output from the solar radiation amount detection unit 17, and when the solar radiation amount decreases, the output suppression correction unit 10 outputs an output power correction command to output the chopper 19. Reduce output power.

  Thus, even in the configuration of the present embodiment including the chopper 19 and the inverter 2, the solar radiation amount is monitored even when the solar radiation amount is reduced while the active power control is in operation, and thus the third embodiment and Similarly, a decrease in the output voltage of the solar panel 1 can be suppressed and the operation can be continued.

  In the first to sixth embodiments, the external command is simply used as time information, and the schedule of the output suppression command is registered in advance in the external command receiving unit 9, and the external command receiving unit 9 outputs in accordance with the schedule. It may be configured to output a suppression command.

  Further, in the fourth to sixth embodiments, a plurality of choppers may be connected to one inverter.

1: Solar panel 2: Inverter 3: Power system 4: Voltage detector 5: Current detector 6: Voltage detector 7: Current detector 8: Control unit 9: External command receiving unit 10: Output suppression control unit 11: Active power control unit 12: changeover switch 13: DC voltage control unit 14: current control unit 15: PWM control unit 16: panel voltage monitoring unit 17: solar radiation amount detection unit 18: solar radiation amount monitoring unit 19: chopper 20: voltage detector 21: Current detector 22: Control unit 23: DC voltage control unit 24: Current control unit 25: PWM control unit 26: Photovoltaic power conversion device 29: Photovoltaic power conversion device 100: External command 101: Gate Pulse signal

Claims (12)

It is a power conversion device for photovoltaic power generation that converts DC power output from a solar panel into AC power by a power converter and outputs it to a system,
The control unit that controls the power converter includes a DC voltage control unit that controls a panel voltage of the solar panel, and an active power control unit that controls output power of the power converter, and according to an external command. And switching the output of the DC voltage control unit and the output of the active power control unit to provide a gate pulse signal for driving the power converter. It is the power converter device for photovoltaic power generation according to claim 1,
When the DC voltage control unit performs DC voltage control for controlling the panel voltage of the solar panel at a constant time and suppresses the output power of the power converter in accordance with an external command, the active power control is performed. An active power control for controlling the output power of the power converter is performed by a unit. It is the power converter device for photovoltaic power generation according to claim 1 or 2,
In the state where the panel voltage of the solar panel is monitored and the active power control unit controls the output power of the power converter by the active power control unit, when the panel voltage decreases, the active power A power converter for photovoltaic power generation, wherein the output power of the power converter by the control unit is suppressed. It is the power converter device for photovoltaic power generation according to claim 1 or 2,
The active power control is performed when the solar radiation amount is reduced in the state in which the active power control is performed by monitoring the solar radiation amount of the solar panel and controlling the output power of the power converter by the active power control unit. The power converter for photovoltaic power generation characterized by suppressing the output electric power of the power converter by a part. It is the power converter device for photovoltaic power generation according to claim 1,
The said power converter has at least one of an inverter or a chopper, The power converter device for photovoltaic power generation characterized by the above-mentioned.
Power conversion device. It is the power converter device for photovoltaic power generation according to claim 1,
The power converter includes a DC circuit having a power storage function, and by storing or discharging the difference between the output power of the solar panel and the output power of the power converter in the DC circuit of the power converter, The said power converter does not output the fluctuation | variation part of the output power of the said solar panel to a system | strain, The power converter device for photovoltaic power generation characterized by the above-mentioned. It is the power converter device for photovoltaic power generation according to claim 6,
A power converter for photovoltaic power generation, wherein a DC voltage of a DC circuit of the power converter varies according to a difference between output power of the solar panel and output power of the power converter. It is the power converter device for photovoltaic power generation according to claim 1,
When performing the active power control, when the output power of the power converter is monotonously decreasing while the solar panel is partially shaded, the output power or output current of the solar panel There is a period in which the power generation increases transiently. It is the power converter device for solar power generation in any one of Claims 1-8,
The active power control unit controls the output power of the power converter to decrease with time in response to a command from the outside. A control method for a photovoltaic power conversion device that converts direct current power output from a solar panel into alternating current power by a power converter and outputs the alternating current power to a system,
The control unit that controls the power converter includes a DC voltage control unit that controls a panel voltage of the solar panel, and an active power control unit that controls output power of the power converter, and according to an external command. Switching the output of the DC voltage control unit and the output of the active power control unit to give a gate pulse signal for driving the power converter,
At regular times, the DC voltage control unit performs maximum power tracking control,
When an external command is given, the active power control unit performs output suppression control,
Thereafter, after reaching a predetermined output, panel voltage control is performed by the DC voltage control unit. It is a control method of the power converter for photovoltaic power generation according to claim 10,
In the said output suppression control, it controls so that the output electric power of the said power converter decreases with time progress, The control method of the power converter device for solar power generation characterized by the above-mentioned. Solar panels,
The solar power generation power conversion device that converts the DC power output from the solar panel into AC power by a power converter and outputs the AC power to the system,
The control unit that controls the power converter includes a DC voltage control unit that controls a panel voltage of the solar panel, and an active power control unit that controls output power of the power converter, and according to an external command. And switching the output of the DC voltage control unit and the output of the active power control unit to provide a gate pulse signal for driving the power converter.

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